Commit graph

826 commits

Author SHA1 Message Date
Jason A. Donenfeld
7ebcfba533 xtensa: use fallback for random_get_entropy() instead of zero
commit e10e2f5803 upstream.

In the event that random_get_entropy() can't access a cycle counter or
similar, falling back to returning 0 is really not the best we can do.
Instead, at least calling random_get_entropy_fallback() would be
preferable, because that always needs to return _something_, even
falling back to jiffies eventually. It's not as though
random_get_entropy_fallback() is super high precision or guaranteed to
be entropic, but basically anything that's not zero all the time is
better than returning zero all the time.

This is accomplished by just including the asm-generic code like on
other architectures, which means we can get rid of the empty stub
function here.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Acked-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-05-30 09:24:06 +02:00
Linus Torvalds
7203062171 TTY/Serial driver changes for 5.18-rc1
Here are the big set of tty and serial driver changes for 5.18-rc1.
 
 Nothing major, some more good cleanups from Jiri and 2 new serial
 drivers.  Highlights include:
 	- termbits cleanups
 	- export symbol cleanups and other core cleanups from Jiri Slaby
 	- new sunplus and mvebu uart drivers (amazing that people are
 	  still creating new uarts...)
 	- samsung serial driver cleanups
 	- ldisc 29 is now "reserved" for experimental/development line
 	  disciplines
 	- lots of other tiny fixes and cleanups to serial drivers and
 	  bindings
 
 All of these have been in linux-next for a while with no reported
 issues.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'tty-5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty/serial driver updates from Greg KH:
 "Here are the big set of tty and serial driver changes for 5.18-rc1.

  Nothing major, some more good cleanups from Jiri and 2 new serial
  drivers. Highlights include:

   - termbits cleanups

   - export symbol cleanups and other core cleanups from Jiri Slaby

   - new sunplus and mvebu uart drivers (amazing that people are still
     creating new uarts...)

   - samsung serial driver cleanups

   - ldisc 29 is now "reserved" for experimental/development line
     disciplines

   - lots of other tiny fixes and cleanups to serial drivers and
     bindings

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'tty-5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (104 commits)
  vt_ioctl: fix potential spectre v1 in VT_DISALLOCATE
  serial: 8250: fix XOFF/XON sending when DMA is used
  tty: serial: samsung: Add ARTPEC-8 support
  dt-bindings: serial: samsung: Add ARTPEC-8 UART
  serial: sc16is7xx: Clear RS485 bits in the shutdown
  tty: serial: samsung: simplify getting OF match data
  tty: serial: samsung: constify variables and pointers
  tty: serial: samsung: constify s3c24xx_serial_drv_data members
  tty: serial: samsung: constify UART name
  tty: serial: samsung: constify s3c24xx_serial_drv_data
  tty: serial: samsung: reduce number of casts
  tty: serial: samsung: embed s3c2410_uartcfg in parent structure
  tty: serial: samsung: embed s3c24xx_uart_info in parent structure
  serial: 8250_tegra: mark acpi_device_id as unused with !ACPI
  tty: serial: bcm63xx: use more precise Kconfig symbol
  serial: SERIAL_SUNPLUS should depend on ARCH_SUNPLUS
  tty: serial: jsm: fix two assignments in if conditions
  tty: serial: jsm: remove redundant assignments to variable linestatus
  serial: 8250_mtk: make two read-only arrays static const
  serial: samsung_tty: do not unlock port->lock for uart_write_wakeup()
  ...
2022-03-28 13:00:51 -07:00
Linus Torvalds
02e2af20f4 Char/Misc and other driver updates for 5.18-rc1
Here is the big set of char/misc and other small driver subsystem
 updates for 5.18-rc1.
 
 Included in here are merges from driver subsystems which contain:
 	- iio driver updates and new drivers
 	- fsi driver updates
 	- fpga driver updates
 	- habanalabs driver updates and support for new hardware
 	- soundwire driver updates and new drivers
 	- phy driver updates and new drivers
 	- coresight driver updates
 	- icc driver updates
 
 Individual changes include:
 	- mei driver updates
 	- interconnect driver updates
 	- new PECI driver subsystem added
 	- vmci driver updates
 	- lots of tiny misc/char driver updates
 
 There will be two merge conflicts with your tree, one in MAINTAINERS
 which is obvious to fix up, and one in drivers/phy/freescale/Kconfig
 which also should be easy to resolve.
 
 All of these have been in linux-next for a while with no reported
 problems.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'char-misc-5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

Pull char/misc and other driver updates from Greg KH:
 "Here is the big set of char/misc and other small driver subsystem
  updates for 5.18-rc1.

  Included in here are merges from driver subsystems which contain:

   - iio driver updates and new drivers

   - fsi driver updates

   - fpga driver updates

   - habanalabs driver updates and support for new hardware

   - soundwire driver updates and new drivers

   - phy driver updates and new drivers

   - coresight driver updates

   - icc driver updates

  Individual changes include:

   - mei driver updates

   - interconnect driver updates

   - new PECI driver subsystem added

   - vmci driver updates

   - lots of tiny misc/char driver updates

  All of these have been in linux-next for a while with no reported
  problems"

* tag 'char-misc-5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (556 commits)
  firmware: google: Properly state IOMEM dependency
  kgdbts: fix return value of __setup handler
  firmware: sysfb: fix platform-device leak in error path
  firmware: stratix10-svc: add missing callback parameter on RSU
  arm64: dts: qcom: add non-secure domain property to fastrpc nodes
  misc: fastrpc: Add dma handle implementation
  misc: fastrpc: Add fdlist implementation
  misc: fastrpc: Add helper function to get list and page
  misc: fastrpc: Add support to secure memory map
  dt-bindings: misc: add fastrpc domain vmid property
  misc: fastrpc: check before loading process to the DSP
  misc: fastrpc: add secure domain support
  dt-bindings: misc: add property to support non-secure DSP
  misc: fastrpc: Add support to get DSP capabilities
  misc: fastrpc: add support for FASTRPC_IOCTL_MEM_MAP/UNMAP
  misc: fastrpc: separate fastrpc device from channel context
  dt-bindings: nvmem: brcm,nvram: add basic NVMEM cells
  dt-bindings: nvmem: make "reg" property optional
  nvmem: brcm_nvram: parse NVRAM content into NVMEM cells
  nvmem: dt-bindings: Fix the error of dt-bindings check
  ...
2022-03-28 12:27:35 -07:00
Linus Torvalds
29c8c18363 Merge branch 'akpm' (patches from Andrew)
Merge yet more updates from Andrew Morton:
 "This is the material which was staged after willystuff in linux-next.

  Subsystems affected by this patch series: mm (debug, selftests,
  pagecache, thp, rmap, migration, kasan, hugetlb, pagemap, madvise),
  and selftests"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (113 commits)
  selftests: kselftest framework: provide "finished" helper
  mm: madvise: MADV_DONTNEED_LOCKED
  mm: fix race between MADV_FREE reclaim and blkdev direct IO read
  mm: generalize ARCH_HAS_FILTER_PGPROT
  mm: unmap_mapping_range_tree() with i_mmap_rwsem shared
  mm: warn on deleting redirtied only if accounted
  mm/huge_memory: remove stale locking logic from __split_huge_pmd()
  mm/huge_memory: remove stale page_trans_huge_mapcount()
  mm/swapfile: remove stale reuse_swap_page()
  mm/khugepaged: remove reuse_swap_page() usage
  mm/huge_memory: streamline COW logic in do_huge_pmd_wp_page()
  mm: streamline COW logic in do_swap_page()
  mm: slightly clarify KSM logic in do_swap_page()
  mm: optimize do_wp_page() for fresh pages in local LRU pagevecs
  mm: optimize do_wp_page() for exclusive pages in the swapcache
  mm/huge_memory: make is_transparent_hugepage() static
  userfaultfd/selftests: enable hugetlb remap and remove event testing
  selftests/vm: add hugetlb madvise MADV_DONTNEED MADV_REMOVE test
  mm: enable MADV_DONTNEED for hugetlb mappings
  kasan: disable LOCKDEP when printing reports
  ...
2022-03-25 10:21:20 -07:00
Linus Torvalds
744465da70 Xtensa updates for v5.18
- remove dependency on the compiler's libgcc
 - allow selection of internal kernel ABI via Kconfig
 - enable compiler plugins support for gcc-12 or newer
 - various minor cleanups and fixes
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Merge tag 'xtensa-20220325' of https://github.com/jcmvbkbc/linux-xtensa

Pull Xtensa updates from Max Filippov:

 - remove dependency on the compiler's libgcc

 - allow selection of internal kernel ABI via Kconfig

 - enable compiler plugins support for gcc-12 or newer

 - various minor cleanups and fixes

* tag 'xtensa-20220325' of https://github.com/jcmvbkbc/linux-xtensa:
  xtensa: define update_mmu_tlb function
  xtensa: fix xtensa_wsr always writing 0
  xtensa: enable plugin support
  xtensa: clean up kernel exit assembly code
  xtensa: rearrange NMI exit path
  xtensa: merge stack alignment definitions
  xtensa: fix DTC warning unit_address_format
  xtensa: fix stop_machine_cpuslocked call in patch_text
  xtensa: make secondary reset vector support conditional
  xtensa: add kernel ABI selection to Kconfig
  xtensa: don't link with libgcc
  xtensa: add helpers for division, remainder and shifts
  xtensa: add missing XCHAL_HAVE_WINDOWED check
  xtensa: use XCHAL_NUM_AREGS as pt_regs::areg size
  xtensa: rename PT_SIZE to PT_KERNEL_SIZE
  xtensa: Remove unused early_read_config_byte() et al declarations
  xtensa: use strscpy to copy strings
  net: xtensa: use strscpy to copy strings
2022-03-25 09:49:39 -07:00
Johannes Weiner
9457056ac4 mm: madvise: MADV_DONTNEED_LOCKED
MADV_DONTNEED historically rejects mlocked ranges, but with MLOCK_ONFAULT
and MCL_ONFAULT allowing to mlock without populating, there are valid use
cases for depopulating locked ranges as well.

Users mlock memory to protect secrets.  There are allocators for secure
buffers that want in-use memory generally mlocked, but cleared and
invalidated memory to give up the physical pages.  This could be done with
explicit munlock -> mlock calls on free -> alloc of course, but that adds
two unnecessary syscalls, heavy mmap_sem write locks, vma splits and
re-merges - only to get rid of the backing pages.

Users also mlockall(MCL_ONFAULT) to suppress sustained paging, but are
okay with on-demand initial population.  It seems valid to selectively
free some memory during the lifetime of such a process, without having to
mess with its overall policy.

Why add a separate flag? Isn't this a pretty niche usecase?

- MADV_DONTNEED has been bailing on locked vmas forever. It's at least
  conceivable that someone, somewhere is relying on mlock to protect
  data from perhaps broader invalidation calls. Changing this behavior
  now could lead to quiet data corruption.

- It also clarifies expectations around MADV_FREE and maybe
  MADV_REMOVE. It avoids the situation where one quietly behaves
  different than the others. MADV_FREE_LOCKED can be added later.

- The combination of mlock() and madvise() in the first place is
  probably niche. But where it happens, I'd say that dropping pages
  from a locked region once they don't contain secrets or won't page
  anymore is much saner than relying on mlock to protect memory from
  speculative or errant invalidation calls. It's just that we can't
  change the default behavior because of the two previous points.

Given that, an explicit new flag seems to make the most sense.

[hannes@cmpxchg.org: fix mips build]

Link: https://lkml.kernel.org/r/20220304171912.305060-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-03-24 19:06:51 -07:00
Linus Torvalds
3ce62cf4dc flexible-array transformations for 5.18-rc1
Hi Linus,
 
 Please, pull the following treewide patch that replaces zero-length arrays with
 flexible-array members. This patch has been baking in linux-next for a
 whole development cycle.
 
 Thanks
 --
 Gustavo
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Merge tag 'flexible-array-transformations-5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux

Pull flexible-array transformations from Gustavo Silva:
 "Treewide patch that replaces zero-length arrays with flexible-array
  members.

  This has been baking in linux-next for a whole development cycle"

* tag 'flexible-array-transformations-5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux:
  treewide: Replace zero-length arrays with flexible-array members
2022-03-24 11:39:32 -07:00
Linus Torvalds
194dfe88d6 asm-generic updates for 5.18
There are three sets of updates for 5.18 in the asm-generic tree:
 
  - The set_fs()/get_fs() infrastructure gets removed for good. This
    was already gone from all major architectures, but now we can
    finally remove it everywhere, which loses some particularly
    tricky and error-prone code.
    There is a small merge conflict against a parisc cleanup, the
    solution is to use their new version.
 
  - The nds32 architecture ends its tenure in the Linux kernel. The
    hardware is still used and the code is in reasonable shape, but
    the mainline port is not actively maintained any more, as all
    remaining users are thought to run vendor kernels that would never
    be updated to a future release.
    There are some obvious conflicts against changes to the removed
    files.
 
  - A series from Masahiro Yamada cleans up some of the uapi header
    files to pass the compile-time checks.
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Merge tag 'asm-generic-5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

Pull asm-generic updates from Arnd Bergmann:
 "There are three sets of updates for 5.18 in the asm-generic tree:

   - The set_fs()/get_fs() infrastructure gets removed for good.

     This was already gone from all major architectures, but now we can
     finally remove it everywhere, which loses some particularly tricky
     and error-prone code. There is a small merge conflict against a
     parisc cleanup, the solution is to use their new version.

   - The nds32 architecture ends its tenure in the Linux kernel.

     The hardware is still used and the code is in reasonable shape, but
     the mainline port is not actively maintained any more, as all
     remaining users are thought to run vendor kernels that would never
     be updated to a future release.

   - A series from Masahiro Yamada cleans up some of the uapi header
     files to pass the compile-time checks"

* tag 'asm-generic-5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: (27 commits)
  nds32: Remove the architecture
  uaccess: remove CONFIG_SET_FS
  ia64: remove CONFIG_SET_FS support
  sh: remove CONFIG_SET_FS support
  sparc64: remove CONFIG_SET_FS support
  lib/test_lockup: fix kernel pointer check for separate address spaces
  uaccess: generalize access_ok()
  uaccess: fix type mismatch warnings from access_ok()
  arm64: simplify access_ok()
  m68k: fix access_ok for coldfire
  MIPS: use simpler access_ok()
  MIPS: Handle address errors for accesses above CPU max virtual user address
  uaccess: add generic __{get,put}_kernel_nofault
  nios2: drop access_ok() check from __put_user()
  x86: use more conventional access_ok() definition
  x86: remove __range_not_ok()
  sparc64: add __{get,put}_kernel_nofault()
  nds32: fix access_ok() checks in get/put_user
  uaccess: fix nios2 and microblaze get_user_8()
  sparc64: fix building assembly files
  ...
2022-03-23 18:03:08 -07:00
Linus Torvalds
9030fb0bb9 Folio changes for 5.18
- Rewrite how munlock works to massively reduce the contention
    on i_mmap_rwsem (Hugh Dickins):
    https://lore.kernel.org/linux-mm/8e4356d-9622-a7f0-b2c-f116b5f2efea@google.com/
  - Sort out the page refcount mess for ZONE_DEVICE pages (Christoph Hellwig):
    https://lore.kernel.org/linux-mm/20220210072828.2930359-1-hch@lst.de/
  - Convert GUP to use folios and make pincount available for order-1
    pages. (Matthew Wilcox)
  - Convert a few more truncation functions to use folios (Matthew Wilcox)
  - Convert page_vma_mapped_walk to use PFNs instead of pages (Matthew Wilcox)
  - Convert rmap_walk to use folios (Matthew Wilcox)
  - Convert most of shrink_page_list() to use a folio (Matthew Wilcox)
  - Add support for creating large folios in readahead (Matthew Wilcox)
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Merge tag 'folio-5.18c' of git://git.infradead.org/users/willy/pagecache

Pull folio updates from Matthew Wilcox:

 - Rewrite how munlock works to massively reduce the contention on
   i_mmap_rwsem (Hugh Dickins):

     https://lore.kernel.org/linux-mm/8e4356d-9622-a7f0-b2c-f116b5f2efea@google.com/

 - Sort out the page refcount mess for ZONE_DEVICE pages (Christoph
   Hellwig):

     https://lore.kernel.org/linux-mm/20220210072828.2930359-1-hch@lst.de/

 - Convert GUP to use folios and make pincount available for order-1
   pages. (Matthew Wilcox)

 - Convert a few more truncation functions to use folios (Matthew
   Wilcox)

 - Convert page_vma_mapped_walk to use PFNs instead of pages (Matthew
   Wilcox)

 - Convert rmap_walk to use folios (Matthew Wilcox)

 - Convert most of shrink_page_list() to use a folio (Matthew Wilcox)

 - Add support for creating large folios in readahead (Matthew Wilcox)

* tag 'folio-5.18c' of git://git.infradead.org/users/willy/pagecache: (114 commits)
  mm/damon: minor cleanup for damon_pa_young
  selftests/vm/transhuge-stress: Support file-backed PMD folios
  mm/filemap: Support VM_HUGEPAGE for file mappings
  mm/readahead: Switch to page_cache_ra_order
  mm/readahead: Align file mappings for non-DAX
  mm/readahead: Add large folio readahead
  mm: Support arbitrary THP sizes
  mm: Make large folios depend on THP
  mm: Fix READ_ONLY_THP warning
  mm/filemap: Allow large folios to be added to the page cache
  mm: Turn can_split_huge_page() into can_split_folio()
  mm/vmscan: Convert pageout() to take a folio
  mm/vmscan: Turn page_check_references() into folio_check_references()
  mm/vmscan: Account large folios correctly
  mm/vmscan: Optimise shrink_page_list for non-PMD-sized folios
  mm/vmscan: Free non-shmem folios without splitting them
  mm/rmap: Constify the rmap_walk_control argument
  mm/rmap: Convert rmap_walk() to take a folio
  mm: Turn page_anon_vma() into folio_anon_vma()
  mm/rmap: Turn page_lock_anon_vma_read() into folio_lock_anon_vma_read()
  ...
2022-03-22 17:03:12 -07:00
Max Filippov
1c4664faa3 xtensa: define update_mmu_tlb function
Before the commit f9ce0be71d ("mm: Cleanup faultaround and finish_fault()
codepaths") there was a call to update_mmu_cache in alloc_set_pte that
used to invalidate TLB entry caching invalid PTE that caused a page
fault. That commit removed that call so now invalid TLB entry survives
causing repetitive page faults on the CPU that took the initial fault
until that TLB entry is occasionally evicted. This issue is spotted by
the xtensa TLB sanity checker.

Fix this issue by defining update_mmu_tlb function that flushes TLB entry
for the faulting address.

Cc: stable@vger.kernel.org # 5.12+
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
2022-03-22 09:45:09 -07:00
Mike Rapoport
7106c51ee9 arch: Add pmd_pfn() where it is missing
We need to use this function in common code, so define it for
architectures and/or configrations that miss it.  The result of
pmd_pfn() will only be used if TRANSPARENT_HUGEPAGE is enabled,
but a function or macro called pmd_pfn() must be defined, even
on machines with two level page tables.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
2022-03-21 12:59:02 -04:00
Max Filippov
a3d0245c58 xtensa: fix xtensa_wsr always writing 0
The commit cad6fade6e ("xtensa: clean up WSR*/RSR*/get_sr/set_sr")
replaced 'WSR' macro in the function xtensa_wsr with 'xtensa_set_sr',
but variable 'v' in the xtensa_set_sr body shadowed the argument 'v'
passed to it, resulting in wrong value written to debug registers.

Fix that by removing intermediate variable from the xtensa_set_sr
macro body.

Cc: stable@vger.kernel.org
Fixes: cad6fade6e ("xtensa: clean up WSR*/RSR*/get_sr/set_sr")
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
2022-03-20 09:53:01 -07:00
Max Filippov
e94dc6bbdf xtensa: merge stack alignment definitions
xtensa currently has two different definitions for stack alignment.
Replace it with single definition usable in both C and assembly.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
2022-03-19 13:08:11 -07:00
Maciej W. Rozycki
66bcd06099 parport_pc: Also enable driver for PCI systems
Nowadays PC-style parallel ports come in the form of PCI and PCIe option
cards and there are some combined parallel/serial option cards as well
that we handle in the parport subsystem.  There is nothing in particular
that would prevent them from being used in any system equipped with PCI
or PCIe connectivity, except that we do not permit the PARPORT_PC config
option to be selected for platforms for which ARCH_MIGHT_HAVE_PC_PARPORT
has not been set for.

The only PCI platforms that actually can't make use of PC-style parallel
port hardware are those newer PCIe systems that have no support for I/O
cycles in the host bridge, required by such parallel ports.  Notably,
this includes the s390 arch, which has port I/O accessors that cause
compilation warnings (promoted to errors with `-Werror'), and there are
other cases such as the POWER9 PHB4 device, though this one has variable
port I/O accessors that depend on the particular system.  Also it is not
clear whether the serial port side of devices enabled by PARPORT_SERIAL
uses port I/O or MMIO.  Finally Super I/O solutions are always either
ISA or platform devices.

Make the PARPORT_PC option selectable also for PCI systems then, except
for the s390 arch, however limit the availability of PARPORT_PC_SUPERIO
to platforms that enable ARCH_MIGHT_HAVE_PC_PARPORT.  Update platforms
accordingly for the required <asm/parport.h> header.

Acked-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2202141955550.34636@angie.orcam.me.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-18 14:01:41 +01:00
Max Filippov
dbf4ed894c xtensa: add helpers for division, remainder and shifts
Don't rely on libgcc presence, build own versions of the helpers with
correct ABI.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
2022-03-09 14:02:40 -08:00
Max Filippov
5b835d4cad xtensa: use XCHAL_NUM_AREGS as pt_regs::areg size
struct pt_regs is used to access both kernel and user exception frames.
User exception frames may contain up to XCHAL_NUM_AREG registers that
task creation and signal delivery code may access, but pt_regs::areg
array has only 16 entries that cover only the kernel exception frame.
This results in the following build error:

arch/xtensa/kernel/process.c: In function 'copy_thread':
arch/xtensa/kernel/process.c:262:52: error: array subscript 53 is above
           array bounds of 'long unsigned int[16]' [-Werror=array-bounds]
  262 |                                 put_user(regs->areg[caller_ars+1],

Change struct pt_regs::areg size to XCHAL_NUM_AREGS so that it covers
the whole user exception frame. Adjust task_pt_regs and drop additional
register copying code from copy_thread now that the whole user exception
stack frame is copied.

Reported-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
2022-03-07 12:02:54 -08:00
Bjorn Helgaas
6496f3a717 xtensa: Remove unused early_read_config_byte() et al declarations
early_read_config_byte() and similar are declared but never defined.
Remove the unused declarations.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Message-Id: <20220121210258.1152803-1-helgaas@kernel.org>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
2022-03-06 20:17:09 -08:00
Kees Cook
92652cf986 xtensa: Implement "current_stack_pointer"
To follow the existing per-arch conventions replace open-coded uses
of asm "sp" as "current_stack_pointer". This will let it be used in
non-arch places (like HARDENED_USERCOPY).

Cc: Chris Zankel <chris@zankel.net>
Cc: Marc Zyngier <maz@kernel.org>
Cc: linux-xtensa@linux-xtensa.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Max Filippov <jcmvbkbc@gmail.com>
Link: https://lore.kernel.org/lkml/CAMo8BfJFJE-n3=AF+pb9_6oF3gzxX7a+7aBrASHjjNX5byqDqw@mail.gmail.com
2022-02-25 18:21:23 -08:00
Arnd Bergmann
dd865f090f
Merge branch 'set_fs-4' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic into asm-generic
Christoph Hellwig and a few others spent a huge effort on removing
set_fs() from most of the important architectures, but about half the
other architectures were never completed even though most of them don't
actually use set_fs() at all.

I did a patch for microblaze at some point, which turned out to be fairly
generic, and now ported it to most other architectures, using new generic
implementations of access_ok() and __{get,put}_kernel_nocheck().

Three architectures (sparc64, ia64, and sh) needed some extra work,
which I also completed.

* 'set_fs-4' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
  uaccess: remove CONFIG_SET_FS
  ia64: remove CONFIG_SET_FS support
  sh: remove CONFIG_SET_FS support
  sparc64: remove CONFIG_SET_FS support
  lib/test_lockup: fix kernel pointer check for separate address spaces
  uaccess: generalize access_ok()
  uaccess: fix type mismatch warnings from access_ok()
  arm64: simplify access_ok()
  m68k: fix access_ok for coldfire
  MIPS: use simpler access_ok()
  MIPS: Handle address errors for accesses above CPU max virtual user address
  uaccess: add generic __{get,put}_kernel_nofault
  nios2: drop access_ok() check from __put_user()
  x86: use more conventional access_ok() definition
  x86: remove __range_not_ok()
  sparc64: add __{get,put}_kernel_nofault()
  nds32: fix access_ok() checks in get/put_user
  uaccess: fix nios2 and microblaze get_user_8()
  uaccess: fix integer overflow on access_ok()
2022-02-25 11:16:58 +01:00
Ilpo Järvinen
787779f8af xtensa: termbits.h is identical to asm-generic one
Remove arch specific termbits.h as there are only trivial space
differences between include/uapi/asm-generic/termbits.h and
arch/xtensa/include/uapi/asm/termbits.h.

$ diff -u0 -b -B include/uapi/asm-generic/termbits.h arch/xtensa/include/uapi/asm/termbits.h
. --- include/uapi/asm-generic/termbits.h       2022-01-10 13:44:42.814107461 +0200
. +++ arch/xtensa/include/uapi/asm/termbits.h   2022-01-10 13:44:42.690106926 +0200
. @@ -2,2 +2,15 @@
. -#ifndef __ASM_GENERIC_TERMBITS_H
. -#define __ASM_GENERIC_TERMBITS_H
. +/*
. + * include/asm-xtensa/termbits.h
. + *
. + * Copied from SH.
. + *
. + * This file is subject to the terms and conditions of the GNU General Public
. + * License.  See the file "COPYING" in the main directory of this archive
. + * for more details.
. + *
. + * Copyright (C) 2001 - 2005 Tensilica Inc.
. + */
. +
. +#ifndef _XTENSA_TERMBITS_H
. +#define _XTENSA_TERMBITS_H
. +
. @@ -200 +221 @@
. -#endif /* __ASM_GENERIC_TERMBITS_H */
. +#endif /* _XTENSA_TERMBITS_H */

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220222115604.7351-3-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-02-25 10:20:37 +01:00
Arnd Bergmann
967747bbc0 uaccess: remove CONFIG_SET_FS
There are no remaining callers of set_fs(), so CONFIG_SET_FS
can be removed globally, along with the thread_info field and
any references to it.

This turns access_ok() into a cheaper check against TASK_SIZE_MAX.

As CONFIG_SET_FS is now gone, drop all remaining references to
set_fs()/get_fs(), mm_segment_t, user_addr_max() and uaccess_kernel().

Acked-by: Sam Ravnborg <sam@ravnborg.org> # for sparc32 changes
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Tested-by: Sergey Matyukevich <sergey.matyukevich@synopsys.com> # for arc changes
Acked-by: Stafford Horne <shorne@gmail.com> # [openrisc, asm-generic]
Acked-by: Dinh Nguyen <dinguyen@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2022-02-25 09:36:06 +01:00
Arnd Bergmann
12700c17fc uaccess: generalize access_ok()
There are many different ways that access_ok() is defined across
architectures, but in the end, they all just compare against the
user_addr_max() value or they accept anything.

Provide one definition that works for most architectures, checking
against TASK_SIZE_MAX for user processes or skipping the check inside
of uaccess_kernel() sections.

For architectures without CONFIG_SET_FS(), this should be the fastest
check, as it comes down to a single comparison of a pointer against a
compile-time constant, while the architecture specific versions tend to
do something more complex for historic reasons or get something wrong.

Type checking for __user annotations is handled inconsistently across
architectures, but this is easily simplified as well by using an inline
function that takes a 'const void __user *' argument. A handful of
callers need an extra __user annotation for this.

Some architectures had trick to use 33-bit or 65-bit arithmetic on the
addresses to calculate the overflow, however this simpler version uses
fewer registers, which means it can produce better object code in the
end despite needing a second (statically predicted) branch.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Mark Rutland <mark.rutland@arm.com> [arm64, asm-generic]
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Stafford Horne <shorne@gmail.com>
Acked-by: Dinh Nguyen <dinguyen@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2022-02-25 09:36:05 +01:00
Gustavo A. R. Silva
5224f79096 treewide: Replace zero-length arrays with flexible-array members
There is a regular need in the kernel to provide a way to declare
having a dynamically sized set of trailing elements in a structure.
Kernel code should always use “flexible array members”[1] for these
cases. The older style of one-element or zero-length arrays should
no longer be used[2].

This code was transformed with the help of Coccinelle:
(next-20220214$ spatch --jobs $(getconf _NPROCESSORS_ONLN) --sp-file script.cocci --include-headers --dir . > output.patch)

@@
identifier S, member, array;
type T1, T2;
@@

struct S {
  ...
  T1 member;
  T2 array[
- 0
  ];
};

UAPI and wireless changes were intentionally excluded from this patch
and will be sent out separately.

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/v5.16/process/deprecated.html#zero-length-and-one-element-arrays

Link: https://github.com/KSPP/linux/issues/78
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2022-02-17 07:00:39 -06:00
Masahiro Yamada
4a3233c1a6
shmbuf.h: add asm/shmbuf.h to UAPI compile-test coverage
asm/shmbuf.h is currently excluded from the UAPI compile-test because of
the errors like follows:

    HDRTEST usr/include/asm/shmbuf.h
  In file included from ./usr/include/asm/shmbuf.h:6,
                   from <command-line>:
  ./usr/include/asm-generic/shmbuf.h:26:33: error: field ‘shm_perm’ has incomplete type
     26 |         struct ipc64_perm       shm_perm;       /* operation perms */
        |                                 ^~~~~~~~
  ./usr/include/asm-generic/shmbuf.h:27:9: error: unknown type name ‘size_t’
     27 |         size_t                  shm_segsz;      /* size of segment (bytes) */
        |         ^~~~~~
  ./usr/include/asm-generic/shmbuf.h:40:9: error: unknown type name ‘__kernel_pid_t’
     40 |         __kernel_pid_t          shm_cpid;       /* pid of creator */
        |         ^~~~~~~~~~~~~~
  ./usr/include/asm-generic/shmbuf.h:41:9: error: unknown type name ‘__kernel_pid_t’
     41 |         __kernel_pid_t          shm_lpid;       /* pid of last operator */
        |         ^~~~~~~~~~~~~~

The errors can be fixed by replacing size_t with __kernel_size_t and by
including proper headers.

Then, remove the no-header-test entry from user/include/Makefile.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2022-02-17 09:09:37 +01:00
Masahiro Yamada
72113d0a7d
signal.h: add linux/signal.h and asm/signal.h to UAPI compile-test coverage
linux/signal.h and asm/signal.h are currently excluded from the UAPI
compile-test because of the errors like follows:

    HDRTEST usr/include/asm/signal.h
  In file included from <command-line>:
  ./usr/include/asm/signal.h:103:9: error: unknown type name ‘size_t’
    103 |         size_t ss_size;
        |         ^~~~~~

The errors can be fixed by replacing size_t with __kernel_size_t.

Then, remove the no-header-test entries from user/include/Makefile.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2022-02-17 09:09:36 +01:00
Linus Torvalds
3689f9f8b0 bitmap patches for 5.17-rc1
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Merge tag 'bitmap-5.17-rc1' of git://github.com/norov/linux

Pull bitmap updates from Yury Norov:

 - introduce for_each_set_bitrange()

 - use find_first_*_bit() instead of find_next_*_bit() where possible

 - unify for_each_bit() macros

* tag 'bitmap-5.17-rc1' of git://github.com/norov/linux:
  vsprintf: rework bitmap_list_string
  lib: bitmap: add performance test for bitmap_print_to_pagebuf
  bitmap: unify find_bit operations
  mm/percpu: micro-optimize pcpu_is_populated()
  Replace for_each_*_bit_from() with for_each_*_bit() where appropriate
  find: micro-optimize for_each_{set,clear}_bit()
  include/linux: move for_each_bit() macros from bitops.h to find.h
  cpumask: replace cpumask_next_* with cpumask_first_* where appropriate
  tools: sync tools/bitmap with mother linux
  all: replace find_next{,_zero}_bit with find_first{,_zero}_bit where appropriate
  cpumask: use find_first_and_bit()
  lib: add find_first_and_bit()
  arch: remove GENERIC_FIND_FIRST_BIT entirely
  include: move find.h from asm_generic to linux
  bitops: move find_bit_*_le functions from le.h to find.h
  bitops: protect find_first_{,zero}_bit properly
2022-01-23 06:20:44 +02:00
Yury Norov
47d8c15615 include: move find.h from asm_generic to linux
find_bit API and bitmap API are closely related, but inclusion paths
are different - include/asm-generic and include/linux, correspondingly.
In the past it made a lot of troubles due to circular dependencies
and/or undefined symbols. Fix this by moving find.h under include/linux.

Signed-off-by: Yury Norov <yury.norov@gmail.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
2022-01-15 08:47:31 -08:00
Ingo Molnar
6773cc31a9 Linux 5.16-rc5
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Merge tag 'v5.16-rc5' into locking/core, to pick up fixes

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2021-12-13 10:48:46 +01:00
Arnd Bergmann
0f09c27469 futex: Fix additional regressions
Naresh reported another architecture that was broken by the same typo that
was already fixed for three architectures: mips also refers to the
futex_atomic_op_inuser_local() function by the wrong name and runs into a
missing closing '}' as well.

Going through the source tree the same typo was found in the documentation
as well as in the xtensa code, both of which ended up escaping the
regression testing so far. In the case of xtensa, it appears that the
broken code path is only used when building for platforms that are not
supported by the default gcc configuration, so they are impossible to test
for with default setups.

After going through these more carefully and fixing up the typos, all
architectures have been build-tested again to ensure that this is now
complete.

Fixes: 4e0d846344 ("futex: Fix sparc32/m68k/nds32 build regression")
Fixes: 3f2bedabb6 ("futex: Ensure futex_atomic_cmpxchg_inatomic() is present")
Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20211203080823.2938839-1-arnd@kernel.org
2021-12-11 23:31:51 +01:00
Sebastian Andrzej Siewior
77993b595a locking: Allow to include asm/spinlock_types.h from linux/spinlock_types_raw.h
The printk header file includes ratelimit_types.h for its __ratelimit()
based usage. It is required for the static initializer used in
printk_ratelimited(). It uses a raw_spinlock_t and includes the
spinlock_types.h.

PREEMPT_RT substitutes spinlock_t with a rtmutex based implementation and so
its spinlock_t implmentation (provided by spinlock_rt.h) includes rtmutex.h and
atomic.h which leads to recursive includes where defines are missing.

By including only the raw_spinlock_t defines it avoids the atomic.h
related includes at this stage.

An example on powerpc:

|  CALL    scripts/atomic/check-atomics.sh
|In file included from include/linux/bug.h:5,
|                 from include/linux/page-flags.h:10,
|                 from kernel/bounds.c:10:
|arch/powerpc/include/asm/page_32.h: In function ‘clear_page’:
|arch/powerpc/include/asm/bug.h:87:4: error: implicit declaration of function â=80=98__WARNâ=80=99 [-Werror=3Dimplicit-function-declaration]
|   87 |    __WARN();    \
|      |    ^~~~~~
|arch/powerpc/include/asm/page_32.h:48:2: note: in expansion of macro ‘WARN_ONâ€=99
|   48 |  WARN_ON((unsigned long)addr & (L1_CACHE_BYTES - 1));
|      |  ^~~~~~~
|arch/powerpc/include/asm/bug.h:58:17: error: invalid application of ‘sizeofâ€=99 to incomplete type ‘struct bug_entryâ€=99
|   58 |     "i" (sizeof(struct bug_entry)), \
|      |                 ^~~~~~
|arch/powerpc/include/asm/bug.h:89:3: note: in expansion of macro ‘BUG_ENTRYâ€=99
|   89 |   BUG_ENTRY(PPC_TLNEI " %4, 0",   \
|      |   ^~~~~~~~~
|arch/powerpc/include/asm/page_32.h:48:2: note: in expansion of macro ‘WARN_ONâ€=99
|   48 |  WARN_ON((unsigned long)addr & (L1_CACHE_BYTES - 1));
|      |  ^~~~~~~
|In file included from arch/powerpc/include/asm/ptrace.h:298,
|                 from arch/powerpc/include/asm/hw_irq.h:12,
|                 from arch/powerpc/include/asm/irqflags.h:12,
|                 from include/linux/irqflags.h:16,
|                 from include/asm-generic/cmpxchg-local.h:6,
|                 from arch/powerpc/include/asm/cmpxchg.h:526,
|                 from arch/powerpc/include/asm/atomic.h:11,
|                 from include/linux/atomic.h:7,
|                 from include/linux/rwbase_rt.h:6,
|                 from include/linux/rwlock_types.h:55,
|                 from include/linux/spinlock_types.h:74,
|                 from include/linux/ratelimit_types.h:7,
|                 from include/linux/printk.h:10,
|                 from include/asm-generic/bug.h:22,
|                 from arch/powerpc/include/asm/bug.h:109,
|                 from include/linux/bug.h:5,
|                 from include/linux/page-flags.h:10,
|                 from kernel/bounds.c:10:
|include/linux/thread_info.h: In function â=80=98copy_overflowâ=80=99:
|include/linux/thread_info.h:210:2: error: implicit declaration of function â=80=98WARNâ=80=99 [-Werror=3Dimplicit-function-declaration]
|  210 |  WARN(1, "Buffer overflow detected (%d < %lu)!\n", size, count);
|      |  ^~~~

The WARN / BUG include pulls in printk.h and then ptrace.h expects WARN
(from bug.h) which is not yet complete. Even hw_irq.h has WARN_ON()
statements.

On POWERPC64 there are missing atomic64 defines while building 32bit
VDSO:
|  VDSO32C arch/powerpc/kernel/vdso32/vgettimeofday.o
|In file included from include/linux/atomic.h:80,
|                 from include/linux/rwbase_rt.h:6,
|                 from include/linux/rwlock_types.h:55,
|                 from include/linux/spinlock_types.h:74,
|                 from include/linux/ratelimit_types.h:7,
|                 from include/linux/printk.h:10,
|                 from include/linux/kernel.h:19,
|                 from arch/powerpc/include/asm/page.h:11,
|                 from arch/powerpc/include/asm/vdso/gettimeofday.h:5,
|                 from include/vdso/datapage.h:137,
|                 from lib/vdso/gettimeofday.c:5,
|                 from <command-line>:
|include/linux/atomic-arch-fallback.h: In function ‘arch_atomic64_incâ€=99:
|include/linux/atomic-arch-fallback.h:1447:2: error: implicit declaration of function ‘arch_atomic64_add’; did you mean ‘arch_atomic_add’? [-Werror=3Dimpl
|icit-function-declaration]
| 1447 |  arch_atomic64_add(1, v);
|      |  ^~~~~~~~~~~~~~~~~
|      |  arch_atomic_add

The generic fallback is not included, atomics itself are not used. If
kernel.h does not include printk.h then it comes later from the bug.h
include.

Allow asm/spinlock_types.h to be included from
linux/spinlock_types_raw.h.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20211129174654.668506-12-bigeasy@linutronix.de
2021-12-07 15:14:12 +01:00
Arnd Bergmann
3f2bedabb6 futex: Ensure futex_atomic_cmpxchg_inatomic() is present
The boot-time detection of futex_atomic_cmpxchg_inatomic() has a bug on
some 32-bit arm builds, and Thomas Gleixner suggested that setting
CONFIG_HAVE_FUTEX_CMPXCHG would avoid the problem, as it is always present
anyway.

Looking into which other architectures could do the same showed that almost
all architectures have it, the exceptions being:

 - some old 32-bit MIPS uniprocessor cores without ll/sc
 - one xtensa variant with no SMP
 - 32-bit SPARC when built for SMP

Fix MIPS And Xtensa by rearranging the generic code to let it be used
as a fallback.

For SPARC, the SMP definition just ends up turning off futex anyway, so
this can be done at Kconfig time instead. Note that sparc32 glibc requires
the CASA instruction for its mutexes anyway, which is only available when
running on SPARCv9 or LEON CPUs, but needs to be implemented in the sparc32
kernel for those.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Max Filippov <jcmvbkbc@gmail.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Rich Felker <dalias@libc.org>
Link: https://lore.kernel.org/r/20211026100432.1730393-1-arnd@kernel.org
2021-11-25 00:02:28 +01:00
Matthew Wilcox (Oracle)
522a0032af Add linux/cacheflush.h
Many architectures do not include asm-generic/cacheflush.h, so turn
the includes on their head and add linux/cacheflush.h which includes
asm/cacheflush.h.

Move the flush_dcache_folio() declaration from asm-generic/cacheflush.h
to linux/cacheflush.h and change linux/highmem.h to include
linux/cacheflush.h instead of asm/cacheflush.h so that all necessary
places will see flush_dcache_folio().

More functions should have their default implementations moved in the
future, but those are for follow-on patches.  This fixes csky, sparc and
sparc64 which were missed in the commit which added flush_dcache_folio().

Fixes: 08b0b0059b ("mm: Add flush_dcache_folio()")
Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
2021-11-17 10:36:15 -05:00
Linus Torvalds
e8f023caee asm-generic: asm/syscall.h cleanup
This is a single cleanup from Peter Collingbourne, removing
 some dead code.
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Merge tag 'asm-generic-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

Pull asm-generic cleanup from Arnd Bergmann:
 "This is a single cleanup from Peter Collingbourne, removing some dead
  code"

* tag 'asm-generic-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
  arch: remove unused function syscall_set_arguments()
2021-11-10 11:22:03 -08:00
Linus Torvalds
00f178e150 Xtensa updates for v5.16
- add support for xtensa cores witout windowed registers option
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Merge tag 'xtensa-20211105' of git://github.com/jcmvbkbc/linux-xtensa

Pull xtensa updates from Max Filippov:

 - add support for xtensa cores without windowed registers option

* tag 'xtensa-20211105' of git://github.com/jcmvbkbc/linux-xtensa:
  xtensa: move section symbols to asm/sections.h
  xtensa: remove unused variable wmask
  xtensa: only build windowed register support code when needed
  xtensa: use register window specific opcodes only when present
  xtensa: implement call0 ABI support in assembly
  xtensa: definitions for call0 ABI
  xtensa: don't use a12 in __xtensa_copy_user in call0 ABI
  xtensa: don't use a12 in strncpy_user
  xtensa: use a14 instead of a15 in inline assembly
  xtensa: move _SimulateUserKernelVectorException out of WindowVectors
2021-11-06 14:54:03 -07:00
Linus Torvalds
9a7e0a90a4 Scheduler updates:
- Revert the printk format based wchan() symbol resolution as it can leak
    the raw value in case that the symbol is not resolvable.
 
  - Make wchan() more robust and work with all kind of unwinders by
    enforcing that the task stays blocked while unwinding is in progress.
 
  - Prevent sched_fork() from accessing an invalid sched_task_group
 
  - Improve asymmetric packing logic
 
  - Extend scheduler statistics to RT and DL scheduling classes and add
    statistics for bandwith burst to the SCHED_FAIR class.
 
  - Properly account SCHED_IDLE entities
 
  - Prevent a potential deadlock when initial priority is assigned to a
    newly created kthread. A recent change to plug a race between cpuset and
    __sched_setscheduler() introduced a new lock dependency which is now
    triggered. Break the lock dependency chain by moving the priority
    assignment to the thread function.
 
  - Fix the idle time reporting in /proc/uptime for NOHZ enabled systems.
 
  - Improve idle balancing in general and especially for NOHZ enabled
    systems.
 
  - Provide proper interfaces for live patching so it does not have to
    fiddle with scheduler internals.
 
  - Add cluster aware scheduling support.
 
  - A small set of tweaks for RT (irqwork, wait_task_inactive(), various
    scheduler options and delaying mmdrop)
 
  - The usual small tweaks and improvements all over the place
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Merge tag 'sched-core-2021-11-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler updates from Thomas Gleixner:

 - Revert the printk format based wchan() symbol resolution as it can
   leak the raw value in case that the symbol is not resolvable.

 - Make wchan() more robust and work with all kind of unwinders by
   enforcing that the task stays blocked while unwinding is in progress.

 - Prevent sched_fork() from accessing an invalid sched_task_group

 - Improve asymmetric packing logic

 - Extend scheduler statistics to RT and DL scheduling classes and add
   statistics for bandwith burst to the SCHED_FAIR class.

 - Properly account SCHED_IDLE entities

 - Prevent a potential deadlock when initial priority is assigned to a
   newly created kthread. A recent change to plug a race between cpuset
   and __sched_setscheduler() introduced a new lock dependency which is
   now triggered. Break the lock dependency chain by moving the priority
   assignment to the thread function.

 - Fix the idle time reporting in /proc/uptime for NOHZ enabled systems.

 - Improve idle balancing in general and especially for NOHZ enabled
   systems.

 - Provide proper interfaces for live patching so it does not have to
   fiddle with scheduler internals.

 - Add cluster aware scheduling support.

 - A small set of tweaks for RT (irqwork, wait_task_inactive(), various
   scheduler options and delaying mmdrop)

 - The usual small tweaks and improvements all over the place

* tag 'sched-core-2021-11-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (69 commits)
  sched/fair: Cleanup newidle_balance
  sched/fair: Remove sysctl_sched_migration_cost condition
  sched/fair: Wait before decaying max_newidle_lb_cost
  sched/fair: Skip update_blocked_averages if we are defering load balance
  sched/fair: Account update_blocked_averages in newidle_balance cost
  x86: Fix __get_wchan() for !STACKTRACE
  sched,x86: Fix L2 cache mask
  sched/core: Remove rq_relock()
  sched: Improve wake_up_all_idle_cpus() take #2
  irq_work: Also rcuwait for !IRQ_WORK_HARD_IRQ on PREEMPT_RT
  irq_work: Handle some irq_work in a per-CPU thread on PREEMPT_RT
  irq_work: Allow irq_work_sync() to sleep if irq_work() no IRQ support.
  sched/rt: Annotate the RT balancing logic irqwork as IRQ_WORK_HARD_IRQ
  sched: Add cluster scheduler level for x86
  sched: Add cluster scheduler level in core and related Kconfig for ARM64
  topology: Represent clusters of CPUs within a die
  sched: Disable -Wunused-but-set-variable
  sched: Add wrapper for get_wchan() to keep task blocked
  x86: Fix get_wchan() to support the ORC unwinder
  proc: Use task_is_running() for wchan in /proc/$pid/stat
  ...
2021-11-01 13:48:52 -07:00
Linus Torvalds
49f8275c7d Memory folios
Add memory folios, a new type to represent either order-0 pages or
 the head page of a compound page.  This should be enough infrastructure
 to support filesystems converting from pages to folios.
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Merge tag 'folio-5.16' of git://git.infradead.org/users/willy/pagecache

Pull memory folios from Matthew Wilcox:
 "Add memory folios, a new type to represent either order-0 pages or the
  head page of a compound page. This should be enough infrastructure to
  support filesystems converting from pages to folios.

  The point of all this churn is to allow filesystems and the page cache
  to manage memory in larger chunks than PAGE_SIZE. The original plan
  was to use compound pages like THP does, but I ran into problems with
  some functions expecting only a head page while others expect the
  precise page containing a particular byte.

  The folio type allows a function to declare that it's expecting only a
  head page. Almost incidentally, this allows us to remove various calls
  to VM_BUG_ON(PageTail(page)) and compound_head().

  This converts just parts of the core MM and the page cache. For 5.17,
  we intend to convert various filesystems (XFS and AFS are ready; other
  filesystems may make it) and also convert more of the MM and page
  cache to folios. For 5.18, multi-page folios should be ready.

  The multi-page folios offer some improvement to some workloads. The
  80% win is real, but appears to be an artificial benchmark (postgres
  startup, which isn't a serious workload). Real workloads (eg building
  the kernel, running postgres in a steady state, etc) seem to benefit
  between 0-10%. I haven't heard of any performance losses as a result
  of this series. Nobody has done any serious performance tuning; I
  imagine that tweaking the readahead algorithm could provide some more
  interesting wins. There are also other places where we could choose to
  create large folios and currently do not, such as writes that are
  larger than PAGE_SIZE.

  I'd like to thank all my reviewers who've offered review/ack tags:
  Christoph Hellwig, David Howells, Jan Kara, Jeff Layton, Johannes
  Weiner, Kirill A. Shutemov, Michal Hocko, Mike Rapoport, Vlastimil
  Babka, William Kucharski, Yu Zhao and Zi Yan.

  I'd also like to thank those who gave feedback I incorporated but
  haven't offered up review tags for this part of the series: Nick
  Piggin, Mel Gorman, Ming Lei, Darrick Wong, Ted Ts'o, John Hubbard,
  Hugh Dickins, and probably a few others who I forget"

* tag 'folio-5.16' of git://git.infradead.org/users/willy/pagecache: (90 commits)
  mm/writeback: Add folio_write_one
  mm/filemap: Add FGP_STABLE
  mm/filemap: Add filemap_get_folio
  mm/filemap: Convert mapping_get_entry to return a folio
  mm/filemap: Add filemap_add_folio()
  mm/filemap: Add filemap_alloc_folio
  mm/page_alloc: Add folio allocation functions
  mm/lru: Add folio_add_lru()
  mm/lru: Convert __pagevec_lru_add_fn to take a folio
  mm: Add folio_evictable()
  mm/workingset: Convert workingset_refault() to take a folio
  mm/filemap: Add readahead_folio()
  mm/filemap: Add folio_mkwrite_check_truncate()
  mm/filemap: Add i_blocks_per_folio()
  mm/writeback: Add folio_redirty_for_writepage()
  mm/writeback: Add folio_account_redirty()
  mm/writeback: Add folio_clear_dirty_for_io()
  mm/writeback: Add folio_cancel_dirty()
  mm/writeback: Add folio_account_cleaned()
  mm/writeback: Add filemap_dirty_folio()
  ...
2021-11-01 08:47:59 -07:00
Max Filippov
bd47cdb789 xtensa: move section symbols to asm/sections.h
Introduce asm/sections.h and move section declarations to this header
from setup.c. Assign section symbols char array type uniformly and drop
address operator from section symbol references in code.
Sort headers in setup.c while at it.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
2021-10-18 22:19:35 -07:00
Max Filippov
da0a4e5c8f xtensa: only build windowed register support code when needed
There's no need in window overflow/underflow/alloca exception handlers
or window spill code when neither kernel nor userspace support windowed
registers. Don't build or link it.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
2021-10-18 22:19:35 -07:00
Max Filippov
5cce39b6aa xtensa: definitions for call0 ABI
Add assembly macros for calls, call arguments, preserved registers,
function entry and return for windowed and call0 ABIs.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
2021-10-18 22:19:34 -07:00
Max Filippov
eda8dd1224 xtensa: use a14 instead of a15 in inline assembly
a15 is a frame pointer in the call0 xtensa ABI, don't use it explicitly
in the inline assembly. Use a14 instead, as it has the same properties
as a15 w.r.t. window overflow.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
2021-10-18 22:19:34 -07:00
Matthew Wilcox (Oracle)
08b0b0059b mm: Add flush_dcache_folio()
This is a default implementation which calls flush_dcache_page() on
each page in the folio.  If architectures can do better, they should
implement their own version of it.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
2021-10-18 07:49:36 -04:00
Kees Cook
42a20f86dc sched: Add wrapper for get_wchan() to keep task blocked
Having a stable wchan means the process must be blocked and for it to
stay that way while performing stack unwinding.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> [arm]
Tested-by: Mark Rutland <mark.rutland@arm.com> [arm64]
Link: https://lkml.kernel.org/r/20211008111626.332092234@infradead.org
2021-10-15 11:25:14 +02:00
Randy Dunlap
d67ed2510d xtensa: use CONFIG_USE_OF instead of CONFIG_OF
CONFIG_OF can be set by a randconfig or by a user -- without setting the
early flattree option (OF_EARLY_FLATTREE).  This causes build errors.
However, if randconfig or a user sets USE_OF in the Xtensa config,
the right kconfig symbols are set to fix the build.

Fixes these build errors:

../arch/xtensa/kernel/setup.c:67:19: error: ‘__dtb_start’ undeclared here (not in a function); did you mean ‘dtb_start’?
   67 | void *dtb_start = __dtb_start;
      |                   ^~~~~~~~~~~
../arch/xtensa/kernel/setup.c: In function 'xtensa_dt_io_area':
../arch/xtensa/kernel/setup.c:201:14: error: implicit declaration of function 'of_flat_dt_is_compatible'; did you mean 'of_machine_is_compatible'? [-Werror=implicit-function-declaration]
  201 |         if (!of_flat_dt_is_compatible(node, "simple-bus"))
../arch/xtensa/kernel/setup.c:204:18: error: implicit declaration of function 'of_get_flat_dt_prop' [-Werror=implicit-function-declaration]
  204 |         ranges = of_get_flat_dt_prop(node, "ranges", &len);
../arch/xtensa/kernel/setup.c:204:16: error: assignment to 'const __be32 *' {aka 'const unsigned int *'} from 'int' makes pointer from integer without a cast [-Werror=int-conversion]
  204 |         ranges = of_get_flat_dt_prop(node, "ranges", &len);
      |                ^
../arch/xtensa/kernel/setup.c: In function 'early_init_devtree':
../arch/xtensa/kernel/setup.c:228:9: error: implicit declaration of function 'early_init_dt_scan'; did you mean 'early_init_devtree'? [-Werror=implicit-function-declaration]
  228 |         early_init_dt_scan(params);
../arch/xtensa/kernel/setup.c:229:9: error: implicit declaration of function 'of_scan_flat_dt' [-Werror=implicit-function-declaration]
  229 |         of_scan_flat_dt(xtensa_dt_io_area, NULL);

xtensa-elf-ld: arch/xtensa/mm/mmu.o:(.text+0x0): undefined reference to `xtensa_kio_paddr'

Fixes: da844a8177 ("xtensa: add device trees support")
Fixes: 6cb971114f ("xtensa: remap io area defined in device tree")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
2021-09-27 06:08:58 -07:00
Peter Collingbourne
7962c2eddb
arch: remove unused function syscall_set_arguments()
This function appears to have been unused since it was first introduced in
commit 828c365cc8 ("tracehook: asm/syscall.h").

Signed-off-by: Peter Collingbourne <pcc@google.com>
Link: https://linux-review.googlesource.com/id/I8ce04f002903a37c0b6c1d16e9b2a3afa716c097
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2021-09-14 16:06:20 +02:00
Arnd Bergmann
e6226997ec asm-generic: reverse GENERIC_{STRNCPY_FROM,STRNLEN}_USER symbols
Most architectures do not need a custom implementation, and in most
cases the generic implementation is preferred, so change the polariy
on these Kconfig symbols to require architectures to select them when
they provide their own version.

The new name is CONFIG_ARCH_HAS_{STRNCPY_FROM,STRNLEN}_USER.

The remaining architectures at the moment are: ia64, mips, parisc,
um and xtensa. We should probably convert these as well, but
I was not sure how far to take this series. Thomas Bogendoerfer
had some concerns about converting mips but may still do some
more detailed measurements to see which version is better.

Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: linux-ia64@vger.kernel.org
Cc: linux-mips@vger.kernel.org
Cc: linux-parisc@vger.kernel.org
Cc: linux-s390@vger.kernel.org
Cc: linux-um@lists.infradead.org
Cc: linux-xtensa@linux-xtensa.org
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Helge Deller <deller@gmx.de> # parisc
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2021-07-30 10:30:21 +02:00
Linus Torvalds
4cad671979 asm-generic/unaligned: Unify asm/unaligned.h around struct helper
The get_unaligned()/put_unaligned() helpers are traditionally architecture
 specific, with the two main variants being the "access-ok.h" version
 that assumes unaligned pointer accesses always work on a particular
 architecture, and the "le-struct.h" version that casts the data to a
 byte aligned type before dereferencing, for architectures that cannot
 always do unaligned accesses in hardware.
 
 Based on the discussion linked below, it appears that the access-ok
 version is not realiable on any architecture, but the struct version
 probably has no downsides. This series changes the code to use the
 same implementation on all architectures, addressing the few exceptions
 separately.
 
 Link: https://lore.kernel.org/lkml/75d07691-1e4f-741f-9852-38c0b4f520bc@synopsys.com/
 Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100363
 Link: https://lore.kernel.org/lkml/20210507220813.365382-14-arnd@kernel.org/
 Link: git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic.git unaligned-rework-v2
 Link: https://lore.kernel.org/lkml/CAHk-=whGObOKruA_bU3aPGZfoDqZM1_9wBkwREp0H0FgR-90uQ@mail.gmail.com/
 Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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Merge tag 'asm-generic-unaligned-5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

Pull asm/unaligned.h unification from Arnd Bergmann:
 "Unify asm/unaligned.h around struct helper

  The get_unaligned()/put_unaligned() helpers are traditionally
  architecture specific, with the two main variants being the
  "access-ok.h" version that assumes unaligned pointer accesses always
  work on a particular architecture, and the "le-struct.h" version that
  casts the data to a byte aligned type before dereferencing, for
  architectures that cannot always do unaligned accesses in hardware.

  Based on the discussion linked below, it appears that the access-ok
  version is not realiable on any architecture, but the struct version
  probably has no downsides. This series changes the code to use the
  same implementation on all architectures, addressing the few
  exceptions separately"

Link: https://lore.kernel.org/lkml/75d07691-1e4f-741f-9852-38c0b4f520bc@synopsys.com/
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100363
Link: https://lore.kernel.org/lkml/20210507220813.365382-14-arnd@kernel.org/
Link: git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic.git unaligned-rework-v2
Link: https://lore.kernel.org/lkml/CAHk-=whGObOKruA_bU3aPGZfoDqZM1_9wBkwREp0H0FgR-90uQ@mail.gmail.com/

* tag 'asm-generic-unaligned-5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
  asm-generic: simplify asm/unaligned.h
  asm-generic: uaccess: 1-byte access is always aligned
  netpoll: avoid put_unaligned() on single character
  mwifiex: re-fix for unaligned accesses
  apparmor: use get_unaligned() only for multi-byte words
  partitions: msdos: fix one-byte get_unaligned()
  asm-generic: unaligned always use struct helpers
  asm-generic: unaligned: remove byteshift helpers
  powerpc: use linux/unaligned/le_struct.h on LE power7
  m68k: select CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
  sh: remove unaligned access for sh4a
  openrisc: always use unaligned-struct header
  asm-generic: use asm-generic/unaligned.h for most architectures
2021-07-02 12:43:40 -07:00
Linus Torvalds
71bd934101 Merge branch 'akpm' (patches from Andrew)
Merge more updates from Andrew Morton:
 "190 patches.

  Subsystems affected by this patch series: mm (hugetlb, userfaultfd,
  vmscan, kconfig, proc, z3fold, zbud, ras, mempolicy, memblock,
  migration, thp, nommu, kconfig, madvise, memory-hotplug, zswap,
  zsmalloc, zram, cleanups, kfence, and hmm), procfs, sysctl, misc,
  core-kernel, lib, lz4, checkpatch, init, kprobes, nilfs2, hfs,
  signals, exec, kcov, selftests, compress/decompress, and ipc"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (190 commits)
  ipc/util.c: use binary search for max_idx
  ipc/sem.c: use READ_ONCE()/WRITE_ONCE() for use_global_lock
  ipc: use kmalloc for msg_queue and shmid_kernel
  ipc sem: use kvmalloc for sem_undo allocation
  lib/decompressors: remove set but not used variabled 'level'
  selftests/vm/pkeys: exercise x86 XSAVE init state
  selftests/vm/pkeys: refill shadow register after implicit kernel write
  selftests/vm/pkeys: handle negative sys_pkey_alloc() return code
  selftests/vm/pkeys: fix alloc_random_pkey() to make it really, really random
  kcov: add __no_sanitize_coverage to fix noinstr for all architectures
  exec: remove checks in __register_bimfmt()
  x86: signal: don't do sas_ss_reset() until we are certain that sigframe won't be abandoned
  hfsplus: report create_date to kstat.btime
  hfsplus: remove unnecessary oom message
  nilfs2: remove redundant continue statement in a while-loop
  kprobes: remove duplicated strong free_insn_page in x86 and s390
  init: print out unknown kernel parameters
  checkpatch: do not complain about positive return values starting with EPOLL
  checkpatch: improve the indented label test
  checkpatch: scripts/spdxcheck.py now requires python3
  ...
2021-07-02 12:08:10 -07:00
Anshuman Khandual
1c2f7d14d8 mm/thp: define default pmd_pgtable()
Currently most platforms define pmd_pgtable() as pmd_page() duplicating
the same code all over.  Instead just define a default value i.e
pmd_page() for pmd_pgtable() and let platforms override when required via
<asm/pgtable.h>.  All the existing platform that override pmd_pgtable()
have been moved into their respective <asm/pgtable.h> header in order to
precede before the new generic definition.  This makes it much cleaner
with reduced code.

Link: https://lkml.kernel.org/r/1623646133-20306-1-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Stafford Horne <shorne@gmail.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Chris Zankel <chris@zankel.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:03 -07:00
Anshuman Khandual
fac7757e1f mm: define default value for FIRST_USER_ADDRESS
Currently most platforms define FIRST_USER_ADDRESS as 0UL duplication the
same code all over.  Instead just define a generic default value (i.e 0UL)
for FIRST_USER_ADDRESS and let the platforms override when required.  This
makes it much cleaner with reduced code.

The default FIRST_USER_ADDRESS here would be skipped in <linux/pgtable.h>
when the given platform overrides its value via <asm/pgtable.h>.

Link: https://lkml.kernel.org/r/1620615725-24623-1-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>	[m68k]
Acked-by: Guo Ren <guoren@kernel.org>			[csky]
Acked-by: Stafford Horne <shorne@gmail.com>		[openrisc]
Acked-by: Catalin Marinas <catalin.marinas@arm.com>	[arm64]
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Palmer Dabbelt <palmerdabbelt@google.com>	[RISC-V]
Cc: Richard Henderson <rth@twiddle.net>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Stafford Horne <shorne@gmail.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Chris Zankel <chris@zankel.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:02 -07:00
David Hildenbrand
4ca9b3859d mm/madvise: introduce MADV_POPULATE_(READ|WRITE) to prefault page tables
I. Background: Sparse Memory Mappings

When we manage sparse memory mappings dynamically in user space - also
sometimes involving MAP_NORESERVE - we want to dynamically populate/
discard memory inside such a sparse memory region.  Example users are
hypervisors (especially implementing memory ballooning or similar
technologies like virtio-mem) and memory allocators.  In addition, we want
to fail in a nice way (instead of generating SIGBUS) if populating does
not succeed because we are out of backend memory (which can happen easily
with file-based mappings, especially tmpfs and hugetlbfs).

While MADV_DONTNEED, MADV_REMOVE and FALLOC_FL_PUNCH_HOLE allow for
reliably discarding memory for most mapping types, there is no generic
approach to populate page tables and preallocate memory.

Although mmap() supports MAP_POPULATE, it is not applicable to the concept
of sparse memory mappings, where we want to populate/discard dynamically
and avoid expensive/problematic remappings.  In addition, we never
actually report errors during the final populate phase - it is best-effort
only.

fallocate() can be used to preallocate file-based memory and fail in a
safe way.  However, it cannot really be used for any private mappings on
anonymous files via memfd due to COW semantics.  In addition, fallocate()
does not actually populate page tables, so we still always get pagefaults
on first access - which is sometimes undesired (i.e., real-time workloads)
and requires real prefaulting of page tables, not just a preallocation of
backend storage.  There might be interesting use cases for sparse memory
regions along with mlockall(MCL_ONFAULT) which fallocate() cannot satisfy
as it does not prefault page tables.

II. On preallcoation/prefaulting from user space

Because we don't have a proper interface, what applications (like QEMU and
databases) end up doing is touching (i.e., reading+writing one byte to not
overwrite existing data) all individual pages.

However, that approach
1) Can result in wear on storage backing, because we end up reading/writing
   each page; this is especially a problem for dax/pmem.
2) Can result in mmap_sem contention when prefaulting via multiple
   threads.
3) Requires expensive signal handling, especially to catch SIGBUS in case
   of hugetlbfs/shmem/file-backed memory. For example, this is
   problematic in hypervisors like QEMU where SIGBUS handlers might already
   be used by other subsystems concurrently to e.g, handle hardware errors.
   "Simply" doing preallocation concurrently from other thread is not that
   easy.

III. On MADV_WILLNEED

Extending MADV_WILLNEED is not an option because
1. It would change the semantics: "Expect access in the near future." and
   "might be a good idea to read some pages" vs. "Definitely populate/
   preallocate all memory and definitely fail on errors.".
2. Existing users (like virtio-balloon in QEMU when deflating the balloon)
   don't want populate/prealloc semantics. They treat this rather as a hint
   to give a little performance boost without too much overhead - and don't
   expect that a lot of memory might get consumed or a lot of time
   might be spent.

IV. MADV_POPULATE_READ and MADV_POPULATE_WRITE

Let's introduce MADV_POPULATE_READ and MADV_POPULATE_WRITE, inspired by
MAP_POPULATE, with the following semantics:
1. MADV_POPULATE_READ can be used to prefault page tables just like
   manually reading each individual page. This will not break any COW
   mappings. The shared zero page might get mapped and no backend storage
   might get preallocated -- allocation might be deferred to
   write-fault time. Especially shared file mappings require an explicit
   fallocate() upfront to actually preallocate backend memory (blocks in
   the file system) in case the file might have holes.
2. If MADV_POPULATE_READ succeeds, all page tables have been populated
   (prefaulted) readable once.
3. MADV_POPULATE_WRITE can be used to preallocate backend memory and
   prefault page tables just like manually writing (or
   reading+writing) each individual page. This will break any COW
   mappings -- e.g., the shared zeropage is never populated.
4. If MADV_POPULATE_WRITE succeeds, all page tables have been populated
   (prefaulted) writable once.
5. MADV_POPULATE_READ and MADV_POPULATE_WRITE cannot be applied to special
   mappings marked with VM_PFNMAP and VM_IO. Also, proper access
   permissions (e.g., PROT_READ, PROT_WRITE) are required. If any such
   mapping is encountered, madvise() fails with -EINVAL.
6. If MADV_POPULATE_READ or MADV_POPULATE_WRITE fails, some page tables
   might have been populated.
7. MADV_POPULATE_READ and MADV_POPULATE_WRITE will return -EHWPOISON
   when encountering a HW poisoned page in the range.
8. Similar to MAP_POPULATE, MADV_POPULATE_READ and MADV_POPULATE_WRITE
   cannot protect from the OOM (Out Of Memory) handler killing the
   process.

While the use case for MADV_POPULATE_WRITE is fairly obvious (i.e.,
preallocate memory and prefault page tables for VMs), one issue is that
whenever we prefault pages writable, the pages have to be marked dirty,
because the CPU could dirty them any time.  while not a real problem for
hugetlbfs or dax/pmem, it can be a problem for shared file mappings: each
page will be marked dirty and has to be written back later when evicting.

MADV_POPULATE_READ allows for optimizing this scenario: Pre-read a whole
mapping from backend storage without marking it dirty, such that eviction
won't have to write it back.  As discussed above, shared file mappings
might require an explciit fallocate() upfront to achieve
preallcoation+prepopulation.

Although sparse memory mappings are the primary use case, this will also
be useful for other preallocate/prefault use cases where MAP_POPULATE is
not desired or the semantics of MAP_POPULATE are not sufficient: as one
example, QEMU users can trigger preallocation/prefaulting of guest RAM
after the mapping was created -- and don't want errors to be silently
suppressed.

Looking at the history, MADV_POPULATE was already proposed in 2013 [1],
however, the main motivation back than was performance improvements --
which should also still be the case.

V. Single-threaded performance comparison

I did a short experiment, prefaulting page tables on completely *empty
mappings/files* and repeated the experiment 10 times.  The results
correspond to the shortest execution time.  In general, the performance
benefit for huge pages is negligible with small mappings.

V.1: Private mappings

POPULATE_READ and POPULATE_WRITE is fastest.  Note that
Reading/POPULATE_READ will populate the shared zeropage where applicable
-- which result in short population times.

The fastest way to allocate backend storage (here: swap or huge pages) and
prefault page tables is POPULATE_WRITE.

V.2: Shared mappings

fallocate() is fastest, however, doesn't prefault page tables.
POPULATE_WRITE is faster than simple writes and read/writes.
POPULATE_READ is faster than simple reads.

Without a fd, the fastest way to allocate backend storage and prefault
page tables is POPULATE_WRITE.  With an fd, the fastest way is usually
FALLOCATE+POPULATE_READ or FALLOCATE+POPULATE_WRITE respectively; one
exception are actual files: FALLOCATE+Read is slightly faster than
FALLOCATE+POPULATE_READ.

The fastest way to allocate backend storage prefault page tables is
FALLOCATE+POPULATE_WRITE -- except when dealing with actual files; then,
FALLOCATE+POPULATE_READ is fastest and won't directly mark all pages as
dirty.

v.3: Detailed results

==================================================
2 MiB MAP_PRIVATE:
**************************************************
Anon 4 KiB     : Read                     :     0.119 ms
Anon 4 KiB     : Write                    :     0.222 ms
Anon 4 KiB     : Read/Write               :     0.380 ms
Anon 4 KiB     : POPULATE_READ            :     0.060 ms
Anon 4 KiB     : POPULATE_WRITE           :     0.158 ms
Memfd 4 KiB    : Read                     :     0.034 ms
Memfd 4 KiB    : Write                    :     0.310 ms
Memfd 4 KiB    : Read/Write               :     0.362 ms
Memfd 4 KiB    : POPULATE_READ            :     0.039 ms
Memfd 4 KiB    : POPULATE_WRITE           :     0.229 ms
Memfd 2 MiB    : Read                     :     0.030 ms
Memfd 2 MiB    : Write                    :     0.030 ms
Memfd 2 MiB    : Read/Write               :     0.030 ms
Memfd 2 MiB    : POPULATE_READ            :     0.030 ms
Memfd 2 MiB    : POPULATE_WRITE           :     0.030 ms
tmpfs          : Read                     :     0.033 ms
tmpfs          : Write                    :     0.313 ms
tmpfs          : Read/Write               :     0.406 ms
tmpfs          : POPULATE_READ            :     0.039 ms
tmpfs          : POPULATE_WRITE           :     0.285 ms
file           : Read                     :     0.033 ms
file           : Write                    :     0.351 ms
file           : Read/Write               :     0.408 ms
file           : POPULATE_READ            :     0.039 ms
file           : POPULATE_WRITE           :     0.290 ms
hugetlbfs      : Read                     :     0.030 ms
hugetlbfs      : Write                    :     0.030 ms
hugetlbfs      : Read/Write               :     0.030 ms
hugetlbfs      : POPULATE_READ            :     0.030 ms
hugetlbfs      : POPULATE_WRITE           :     0.030 ms
**************************************************
4096 MiB MAP_PRIVATE:
**************************************************
Anon 4 KiB     : Read                     :   237.940 ms
Anon 4 KiB     : Write                    :   708.409 ms
Anon 4 KiB     : Read/Write               :  1054.041 ms
Anon 4 KiB     : POPULATE_READ            :   124.310 ms
Anon 4 KiB     : POPULATE_WRITE           :   572.582 ms
Memfd 4 KiB    : Read                     :   136.928 ms
Memfd 4 KiB    : Write                    :   963.898 ms
Memfd 4 KiB    : Read/Write               :  1106.561 ms
Memfd 4 KiB    : POPULATE_READ            :    78.450 ms
Memfd 4 KiB    : POPULATE_WRITE           :   805.881 ms
Memfd 2 MiB    : Read                     :   357.116 ms
Memfd 2 MiB    : Write                    :   357.210 ms
Memfd 2 MiB    : Read/Write               :   357.606 ms
Memfd 2 MiB    : POPULATE_READ            :   356.094 ms
Memfd 2 MiB    : POPULATE_WRITE           :   356.937 ms
tmpfs          : Read                     :   137.536 ms
tmpfs          : Write                    :   954.362 ms
tmpfs          : Read/Write               :  1105.954 ms
tmpfs          : POPULATE_READ            :    80.289 ms
tmpfs          : POPULATE_WRITE           :   822.826 ms
file           : Read                     :   137.874 ms
file           : Write                    :   987.025 ms
file           : Read/Write               :  1107.439 ms
file           : POPULATE_READ            :    80.413 ms
file           : POPULATE_WRITE           :   857.622 ms
hugetlbfs      : Read                     :   355.607 ms
hugetlbfs      : Write                    :   355.729 ms
hugetlbfs      : Read/Write               :   356.127 ms
hugetlbfs      : POPULATE_READ            :   354.585 ms
hugetlbfs      : POPULATE_WRITE           :   355.138 ms
**************************************************
2 MiB MAP_SHARED:
**************************************************
Anon 4 KiB     : Read                     :     0.394 ms
Anon 4 KiB     : Write                    :     0.348 ms
Anon 4 KiB     : Read/Write               :     0.400 ms
Anon 4 KiB     : POPULATE_READ            :     0.326 ms
Anon 4 KiB     : POPULATE_WRITE           :     0.273 ms
Anon 2 MiB     : Read                     :     0.030 ms
Anon 2 MiB     : Write                    :     0.030 ms
Anon 2 MiB     : Read/Write               :     0.030 ms
Anon 2 MiB     : POPULATE_READ            :     0.030 ms
Anon 2 MiB     : POPULATE_WRITE           :     0.030 ms
Memfd 4 KiB    : Read                     :     0.412 ms
Memfd 4 KiB    : Write                    :     0.372 ms
Memfd 4 KiB    : Read/Write               :     0.419 ms
Memfd 4 KiB    : POPULATE_READ            :     0.343 ms
Memfd 4 KiB    : POPULATE_WRITE           :     0.288 ms
Memfd 4 KiB    : FALLOCATE                :     0.137 ms
Memfd 4 KiB    : FALLOCATE+Read           :     0.446 ms
Memfd 4 KiB    : FALLOCATE+Write          :     0.330 ms
Memfd 4 KiB    : FALLOCATE+Read/Write     :     0.454 ms
Memfd 4 KiB    : FALLOCATE+POPULATE_READ  :     0.379 ms
Memfd 4 KiB    : FALLOCATE+POPULATE_WRITE :     0.268 ms
Memfd 2 MiB    : Read                     :     0.030 ms
Memfd 2 MiB    : Write                    :     0.030 ms
Memfd 2 MiB    : Read/Write               :     0.030 ms
Memfd 2 MiB    : POPULATE_READ            :     0.030 ms
Memfd 2 MiB    : POPULATE_WRITE           :     0.030 ms
Memfd 2 MiB    : FALLOCATE                :     0.030 ms
Memfd 2 MiB    : FALLOCATE+Read           :     0.031 ms
Memfd 2 MiB    : FALLOCATE+Write          :     0.031 ms
Memfd 2 MiB    : FALLOCATE+Read/Write     :     0.031 ms
Memfd 2 MiB    : FALLOCATE+POPULATE_READ  :     0.030 ms
Memfd 2 MiB    : FALLOCATE+POPULATE_WRITE :     0.030 ms
tmpfs          : Read                     :     0.416 ms
tmpfs          : Write                    :     0.369 ms
tmpfs          : Read/Write               :     0.425 ms
tmpfs          : POPULATE_READ            :     0.346 ms
tmpfs          : POPULATE_WRITE           :     0.295 ms
tmpfs          : FALLOCATE                :     0.139 ms
tmpfs          : FALLOCATE+Read           :     0.447 ms
tmpfs          : FALLOCATE+Write          :     0.333 ms
tmpfs          : FALLOCATE+Read/Write     :     0.454 ms
tmpfs          : FALLOCATE+POPULATE_READ  :     0.380 ms
tmpfs          : FALLOCATE+POPULATE_WRITE :     0.272 ms
file           : Read                     :     0.191 ms
file           : Write                    :     0.511 ms
file           : Read/Write               :     0.524 ms
file           : POPULATE_READ            :     0.196 ms
file           : POPULATE_WRITE           :     0.434 ms
file           : FALLOCATE                :     0.004 ms
file           : FALLOCATE+Read           :     0.197 ms
file           : FALLOCATE+Write          :     0.554 ms
file           : FALLOCATE+Read/Write     :     0.480 ms
file           : FALLOCATE+POPULATE_READ  :     0.201 ms
file           : FALLOCATE+POPULATE_WRITE :     0.381 ms
hugetlbfs      : Read                     :     0.030 ms
hugetlbfs      : Write                    :     0.030 ms
hugetlbfs      : Read/Write               :     0.030 ms
hugetlbfs      : POPULATE_READ            :     0.030 ms
hugetlbfs      : POPULATE_WRITE           :     0.030 ms
hugetlbfs      : FALLOCATE                :     0.030 ms
hugetlbfs      : FALLOCATE+Read           :     0.031 ms
hugetlbfs      : FALLOCATE+Write          :     0.031 ms
hugetlbfs      : FALLOCATE+Read/Write     :     0.030 ms
hugetlbfs      : FALLOCATE+POPULATE_READ  :     0.030 ms
hugetlbfs      : FALLOCATE+POPULATE_WRITE :     0.030 ms
**************************************************
4096 MiB MAP_SHARED:
**************************************************
Anon 4 KiB     : Read                     :  1053.090 ms
Anon 4 KiB     : Write                    :   913.642 ms
Anon 4 KiB     : Read/Write               :  1060.350 ms
Anon 4 KiB     : POPULATE_READ            :   893.691 ms
Anon 4 KiB     : POPULATE_WRITE           :   782.885 ms
Anon 2 MiB     : Read                     :   358.553 ms
Anon 2 MiB     : Write                    :   358.419 ms
Anon 2 MiB     : Read/Write               :   357.992 ms
Anon 2 MiB     : POPULATE_READ            :   357.533 ms
Anon 2 MiB     : POPULATE_WRITE           :   357.808 ms
Memfd 4 KiB    : Read                     :  1078.144 ms
Memfd 4 KiB    : Write                    :   942.036 ms
Memfd 4 KiB    : Read/Write               :  1100.391 ms
Memfd 4 KiB    : POPULATE_READ            :   925.829 ms
Memfd 4 KiB    : POPULATE_WRITE           :   804.394 ms
Memfd 4 KiB    : FALLOCATE                :   304.632 ms
Memfd 4 KiB    : FALLOCATE+Read           :  1163.359 ms
Memfd 4 KiB    : FALLOCATE+Write          :   933.186 ms
Memfd 4 KiB    : FALLOCATE+Read/Write     :  1187.304 ms
Memfd 4 KiB    : FALLOCATE+POPULATE_READ  :  1013.660 ms
Memfd 4 KiB    : FALLOCATE+POPULATE_WRITE :   794.560 ms
Memfd 2 MiB    : Read                     :   358.131 ms
Memfd 2 MiB    : Write                    :   358.099 ms
Memfd 2 MiB    : Read/Write               :   358.250 ms
Memfd 2 MiB    : POPULATE_READ            :   357.563 ms
Memfd 2 MiB    : POPULATE_WRITE           :   357.334 ms
Memfd 2 MiB    : FALLOCATE                :   356.735 ms
Memfd 2 MiB    : FALLOCATE+Read           :   358.152 ms
Memfd 2 MiB    : FALLOCATE+Write          :   358.331 ms
Memfd 2 MiB    : FALLOCATE+Read/Write     :   358.018 ms
Memfd 2 MiB    : FALLOCATE+POPULATE_READ  :   357.286 ms
Memfd 2 MiB    : FALLOCATE+POPULATE_WRITE :   357.523 ms
tmpfs          : Read                     :  1087.265 ms
tmpfs          : Write                    :   950.840 ms
tmpfs          : Read/Write               :  1107.567 ms
tmpfs          : POPULATE_READ            :   922.605 ms
tmpfs          : POPULATE_WRITE           :   810.094 ms
tmpfs          : FALLOCATE                :   306.320 ms
tmpfs          : FALLOCATE+Read           :  1169.796 ms
tmpfs          : FALLOCATE+Write          :   933.730 ms
tmpfs          : FALLOCATE+Read/Write     :  1191.610 ms
tmpfs          : FALLOCATE+POPULATE_READ  :  1020.474 ms
tmpfs          : FALLOCATE+POPULATE_WRITE :   798.945 ms
file           : Read                     :   654.101 ms
file           : Write                    :  1259.142 ms
file           : Read/Write               :  1289.509 ms
file           : POPULATE_READ            :   661.642 ms
file           : POPULATE_WRITE           :  1106.816 ms
file           : FALLOCATE                :     1.864 ms
file           : FALLOCATE+Read           :   656.328 ms
file           : FALLOCATE+Write          :  1153.300 ms
file           : FALLOCATE+Read/Write     :  1180.613 ms
file           : FALLOCATE+POPULATE_READ  :   668.347 ms
file           : FALLOCATE+POPULATE_WRITE :   996.143 ms
hugetlbfs      : Read                     :   357.245 ms
hugetlbfs      : Write                    :   357.413 ms
hugetlbfs      : Read/Write               :   357.120 ms
hugetlbfs      : POPULATE_READ            :   356.321 ms
hugetlbfs      : POPULATE_WRITE           :   356.693 ms
hugetlbfs      : FALLOCATE                :   355.927 ms
hugetlbfs      : FALLOCATE+Read           :   357.074 ms
hugetlbfs      : FALLOCATE+Write          :   357.120 ms
hugetlbfs      : FALLOCATE+Read/Write     :   356.983 ms
hugetlbfs      : FALLOCATE+POPULATE_READ  :   356.413 ms
hugetlbfs      : FALLOCATE+POPULATE_WRITE :   356.266 ms
**************************************************

[1] https://lkml.org/lkml/2013/6/27/698

[akpm@linux-foundation.org: coding style fixes]

Link: https://lkml.kernel.org/r/20210419135443.12822-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Chris Zankel <chris@zankel.net>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rolf Eike Beer <eike-kernel@sf-tec.de>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30 20:47:30 -07:00