In testing the "Fix non-access data TLB cache flush faults" change,
I noticed a significant improvement in glibc build and check times.
This led me to investigate the parisc_cache_flush_threshold setting.
It determines when we switch from line flushing to whole cache flushing.
It turned out that the parisc_cache_flush_threshold setting on
mako and mako2 machines (PA8800 and PA8900 processors) was way too
small. Adjusting this setting provided almost a factor two improvement
in the glibc build and check time.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
Userspace is up to now limited to 32-bit, so it's sufficient to print
only 32-bit values when showing pointer addresses.
Signed-off-by: Helge Deller <deller@gmx.de>
Convert the inline assembly code to use the automatic EFAULT exception
handler. With that the fixup code can be dropped.
The other change is to allow double-word only when a 64-bit kernel is
used instead of depending on CONFIG_PA20.
Signed-off-by: Helge Deller <deller@gmx.de>
The get_current() code uses the mfctl() macro to get the pointer to the
current task struct from %cr30. The problem with the mfctl() macro is,
that it is marked volatile which is basically correct, because mfctl()
is used to get e.g. the current internal timer or interrupt flags as
well.
But specifically the task struct pointer (%cr30) doesn't change over
time when the kernel executes code for a task.
So, by dropping the volatile when retrieving %cr30 the compiler is now
able to get this value only once and optimize the generated code a lot.
A bloat-o-meter comparism shows that this patch saves ~5kB kernel code
on a 32-bit kernel and ~6kB kernel code on a 64-bit kernel.
Signed-off-by: Helge Deller <deller@gmx.de>
Instead of hardcoding the space registers as strings, use the SR_USER
and SR_KERNEL constants to form the space register in the access
functions.
Signed-off-by: Helge Deller <deller@gmx.de>
Provide defines for space registers (SR_KERNEL, SR_USER, ...) which
should be used instead of hardcoding the values.
Signed-off-by: Helge Deller <deller@gmx.de>
This patch drops the CONFIG_PARISC_SELF_EXTRACT option.
The palo boot loader is able to decompress a kernel which was compressed
with gzip. That possibility was useful when the Linux kernel
self-extracting feature wasn't implemented yet.
Beside the fact that the self-extracting feature offers much better
compression rates, we do support self-extracting kernels already since
kernel v4.14, so now it's really time to get rid of that old option and
always use the self-extractor.
Signed-off-by: Helge Deller <deller@gmx.de>
Add minimal vDSO support, which provides the signal trampoline helpers,
but none of the userspace syscall helpers like time wrappers.
The big benefit of this vDSO implementation is, that we now don't need
an executeable stack any longer. PA-RISC is one of the last
architectures where an executeable stack was needed in oder to implement
the signal trampolines by putting assembly instructions on the stack
which then gets executed. Instead the kernel will provide the relevant
code in the vDSO page and only put the pointers to the signal
information on the stack.
By dropping the need for executable stacks we avoid running into issues
with applications which want non executable stacks for security reasons.
Additionally, alternative stacks on memory areas without exec
permissions are supported too.
This code is based on an initial implementation by Randolph Chung from 2006:
https://lore.kernel.org/linux-parisc/4544A34A.6080700@tausq.org/
I did the porting and lifted the code to current code base. Dave fixed
the unwind code so that gdb and glibc are able to backtrace through the
code. An additional patch to gdb will be pushed upstream by Dave.
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Dave Anglin <dave.anglin@bell.net>
Cc: Randolph Chung <randolph@tausq.org>
Signed-off-by: Helge Deller <deller@gmx.de>
With the latest cache fix for non-access faults and the support for
non-access faults (code 17) in handle_interruption, we can remove
the fast path emulation for fdc, fic, pdc, lpa, probe and probei
instructions.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
Currently, the parisc kernel does not fully support non-access TLB
fault handling for probe instructions. In the fast path, we set the
target register to zero if it is not a shadowed register. The slow
path is not implemented, so we call do_page_fault. The architecture
indicates that non-access faults should not cause a page fault from
disk.
This change adds to code to provide non-access fault support for
probe instructions. It also modifies the handling of faults on
userspace so that if the address lies in a valid VMA and the access
type matches that for the VMA, the probe target register is set to
one. Otherwise, the target register is set to zero.
This was done to make probe instructions more useful for userspace.
Probe instructions are not very useful if they set the target register
to zero whenever a page is not present in memory. Nominally, the
purpose of the probe instruction is determine whether read or write
access to a given address is allowed.
This fixes a problem in function pointer comparison noticed in the
glibc testsuite (stdio-common/tst-vfprintf-user-type). The same
problem is likely in glibc (_dl_lookup_address).
V2 adds flush and lpa instruction support to handle_nadtlb_fault.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
When a page is not present, we get non-access data TLB faults from
the fdc and fic instructions in flush_user_dcache_range_asm and
flush_user_icache_range_asm. When these occur, the cache line is
not invalidated and potentially we get memory corruption. The
problem was hidden by the nullification of the flush instructions.
These faults also affect performance. With pa8800/pa8900 processors,
there will be 32 faults per 4 KB page since the cache line is 128
bytes. There will be more faults with earlier processors.
The problem is fixed by using flush_cache_pages(). It does the flush
using a tmp alias mapping.
The flush_cache_pages() call in flush_cache_range() flushed too
large a range.
V2: Remove unnecessary preempt_disable() and preempt_enable() calls.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
Fix 3 bugs:
a) emulate_stw() doesn't return the error code value, so faulting
instructions are not reported and aborted.
b) Tell emulate_ldw() to handle fldw_l as floating point instruction
c) Tell emulate_ldw() to handle ldw_m as integer instruction
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org
Usually the kernel provides fixup routines to emulate the fldd and fstd
floating-point instructions if they load or store 8-byte from/to a not
natuarally aligned memory location.
On a 32-bit kernel I noticed that those unaligned handlers didn't worked and
instead the application got a SEGV.
While checking the code I found two problems:
First, the OPCODE_FLDD_L and OPCODE_FSTD_L cases were ifdef'ed out by the
CONFIG_PA20 option, and as such those weren't built on a pure 32-bit kernel.
This is now fixed by moving the CONFIG_PA20 #ifdef to prevent the compilation
of OPCODE_LDD_L and OPCODE_FSTD_L only, and handling the fldd and fstd
instructions.
The second problem are two bugs in the 32-bit inline assembly code, where the
wrong registers where used. The calculation of the natural alignment used %2
(vall) instead of %3 (ior), and the first word was stored back to address %1
(valh) instead of %3 (ior).
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org
After commit 4b9d2a731c ("parisc: Switch user access functions
to signal errors in r29 instead of r8") bash suddenly started
to report those warnings after login:
-bash: cannot set terminal process group (-1): Bad file descriptor
-bash: no job control in this shell
It turned out, that a function call inside a put_user(), e.g.:
put_user(vt_do_kdgkbmode(console), (int __user *)arg);
clobbered the error register (r29) and thus the put_user() call itself
seem to have failed.
Rearrange the C-code to pre-calculate the intermediate value
and then do the put_user().
Additionally prefer the "+" constraint on pu_err and gu_err registers
to tell the compiler that those operands are both read and written by
the assembly instruction.
Reported-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
Fixes: 4b9d2a731c ("parisc: Switch user access functions to signal errors in r29 instead of r8")
Signed-off-by: Helge Deller <deller@gmx.de>
It happens quite often that people use the wrong compiler to build the
kernel:
make ARCH=parisc -> builds the 32-bit kernel
make ARCH=parisc64 -> builds the 64-bit kernel
This patch adds a sanity check which errors out with an instruction how
use the correct ARCH= option.
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org # v5.15+
It's a followup to the previous commit f15309d7ad ("parisc: Add
ioread64_hi_lo() and iowrite64_hi_lo()") which does only half of
the job. Add the rest, so we won't get a new kernel test robot
reports.
Fixes: f15309d7ad ("parisc: Add ioread64_hi_lo() and iowrite64_hi_lo()")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Helge Deller <deller@gmx.de>
With huge kernel pages, we randomly eat a SPARC in map_pages(). This
is fixed by dropping __init from the declaration.
However, map_pages references the __init routine memblock_alloc_try_nid
via memblock_alloc. Thus, it needs to be marked with __ref.
memblock_alloc is only called before the kernel text is set to readonly.
The __ref on free_initmem is no longer needed.
Comment regarding map_pages being in the init section is removed.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: Helge Deller <deller@gmx.de>
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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
- a memory leak fix in an error path in pdc_stable (Miaoqian Lin)
- two compiler warning fixes in the TOC code
- added autodetection for currently used console type (serial or graphics)
which inserts console=<type> if it's missing
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Merge tag 'for-5.17/parisc-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux
Pull more parisc architecture updates from Helge Deller:
"Fixes and enhancements:
- a memory leak fix in an error path in pdc_stable (Miaoqian Lin)
- two compiler warning fixes in the TOC code
- added autodetection for currently used console type (serial or
graphics) which inserts console=<type> if it's missing"
* tag 'for-5.17/parisc-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
parisc: pdc_stable: Fix memory leak in pdcs_register_pathentries
parisc: Fix missing prototype for 'toc_intr' warning in toc.c
parisc: Autodetect default output device and set console= kernel parameter
parisc: Use safer strscpy() in setup_cmdline()
parisc: Add visible flag to toc_stack variable
Fix a missing prototype warning noticed by the kernel test robot.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Usually palo (the PA-RISC boot loader) will check at boot time if the
machine/firmware was configured to use the serial line (ttyS0, SERIAL_x)
or the graphical display (tty0, graph) as default output device and add
the correct "console=ttyS0" or "console=tty0" Linux kernel parameter to
the kernel command line when starting the Linux kernel.
But the kernel could also have been started via the HP-UX boot loader
or directly in qemu, in which cases the console parameter is missing.
This patch fixes this problem by adding the correct console= parameter
if it's missing in the current kernel command line.
Signed-off-by: Helge Deller <deller@gmx.de>
- Add new kconfig target 'make mod2noconfig', which will be useful to
speed up the build and test iteration.
- Raise the minimum supported version of LLVM to 11.0.0
- Refactor certs/Makefile
- Change the format of include/config/auto.conf to stop double-quoting
string type CONFIG options.
- Fix ARCH=sh builds in dash
- Separate compression macros for general purposes (cmd_bzip2 etc.) and
the ones for decompressors (cmd_bzip2_with_size etc.)
- Misc Makefile cleanups
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Merge tag 'kbuild-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
- Add new kconfig target 'make mod2noconfig', which will be useful to
speed up the build and test iteration.
- Raise the minimum supported version of LLVM to 11.0.0
- Refactor certs/Makefile
- Change the format of include/config/auto.conf to stop double-quoting
string type CONFIG options.
- Fix ARCH=sh builds in dash
- Separate compression macros for general purposes (cmd_bzip2 etc.) and
the ones for decompressors (cmd_bzip2_with_size etc.)
- Misc Makefile cleanups
* tag 'kbuild-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (34 commits)
kbuild: add cmd_file_size
arch: decompressor: remove useless vmlinux.bin.all-y
kbuild: rename cmd_{bzip2,lzma,lzo,lz4,xzkern,zstd22}
kbuild: drop $(size_append) from cmd_zstd
sh: rename suffix-y to suffix_y
doc: kbuild: fix default in `imply` table
microblaze: use built-in function to get CPU_{MAJOR,MINOR,REV}
certs: move scripts/extract-cert to certs/
kbuild: do not quote string values in include/config/auto.conf
kbuild: do not include include/config/auto.conf from shell scripts
certs: simplify $(srctree)/ handling and remove config_filename macro
kbuild: stop using config_filename in scripts/Makefile.modsign
certs: remove misleading comments about GCC PR
certs: refactor file cleaning
certs: remove unneeded -I$(srctree) option for system_certificates.o
certs: unify duplicated cmd_extract_certs and improve the log
certs: use $< and $@ to simplify the key generation rule
kbuild: remove headers_check stub
kbuild: move headers_check.pl to usr/include/
certs: use if_changed to re-generate the key when the key type is changed
...
Pull signal/exit/ptrace updates from Eric Biederman:
"This set of changes deletes some dead code, makes a lot of cleanups
which hopefully make the code easier to follow, and fixes bugs found
along the way.
The end-game which I have not yet reached yet is for fatal signals
that generate coredumps to be short-circuit deliverable from
complete_signal, for force_siginfo_to_task not to require changing
userspace configured signal delivery state, and for the ptrace stops
to always happen in locations where we can guarantee on all
architectures that the all of the registers are saved and available on
the stack.
Removal of profile_task_ext, profile_munmap, and profile_handoff_task
are the big successes for dead code removal this round.
A bunch of small bug fixes are included, as most of the issues
reported were small enough that they would not affect bisection so I
simply added the fixes and did not fold the fixes into the changes
they were fixing.
There was a bug that broke coredumps piped to systemd-coredump. I
dropped the change that caused that bug and replaced it entirely with
something much more restrained. Unfortunately that required some
rebasing.
Some successes after this set of changes: There are few enough calls
to do_exit to audit in a reasonable amount of time. The lifetime of
struct kthread now matches the lifetime of struct task, and the
pointer to struct kthread is no longer stored in set_child_tid. The
flag SIGNAL_GROUP_COREDUMP is removed. The field group_exit_task is
removed. Issues where task->exit_code was examined with
signal->group_exit_code should been examined were fixed.
There are several loosely related changes included because I am
cleaning up and if I don't include them they will probably get lost.
The original postings of these changes can be found at:
https://lkml.kernel.org/r/87a6ha4zsd.fsf@email.froward.int.ebiederm.orghttps://lkml.kernel.org/r/87bl1kunjj.fsf@email.froward.int.ebiederm.orghttps://lkml.kernel.org/r/87r19opkx1.fsf_-_@email.froward.int.ebiederm.org
I trimmed back the last set of changes to only the obviously correct
once. Simply because there was less time for review than I had hoped"
* 'signal-for-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (44 commits)
ptrace/m68k: Stop open coding ptrace_report_syscall
ptrace: Remove unused regs argument from ptrace_report_syscall
ptrace: Remove second setting of PT_SEIZED in ptrace_attach
taskstats: Cleanup the use of task->exit_code
exit: Use the correct exit_code in /proc/<pid>/stat
exit: Fix the exit_code for wait_task_zombie
exit: Coredumps reach do_group_exit
exit: Remove profile_handoff_task
exit: Remove profile_task_exit & profile_munmap
signal: clean up kernel-doc comments
signal: Remove the helper signal_group_exit
signal: Rename group_exit_task group_exec_task
coredump: Stop setting signal->group_exit_task
signal: Remove SIGNAL_GROUP_COREDUMP
signal: During coredumps set SIGNAL_GROUP_EXIT in zap_process
signal: Make coredump handling explicit in complete_signal
signal: Have prepare_signal detect coredumps using signal->core_state
signal: Have the oom killer detect coredumps using signal->core_state
exit: Move force_uaccess back into do_exit
exit: Guarantee make_task_dead leaks the tsk when calling do_task_exit
...
Merge misc updates from Andrew Morton:
"146 patches.
Subsystems affected by this patch series: kthread, ia64, scripts,
ntfs, squashfs, ocfs2, vfs, and mm (slab-generic, slab, kmemleak,
dax, kasan, debug, pagecache, gup, shmem, frontswap, memremap,
memcg, selftests, pagemap, dma, vmalloc, memory-failure, hugetlb,
userfaultfd, vmscan, mempolicy, oom-kill, hugetlbfs, migration, thp,
ksm, page-poison, percpu, rmap, zswap, zram, cleanups, hmm, and
damon)"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (146 commits)
mm/damon: hide kernel pointer from tracepoint event
mm/damon/vaddr: hide kernel pointer from damon_va_three_regions() failure log
mm/damon/vaddr: use pr_debug() for damon_va_three_regions() failure logging
mm/damon/dbgfs: remove an unnecessary variable
mm/damon: move the implementation of damon_insert_region to damon.h
mm/damon: add access checking for hugetlb pages
Docs/admin-guide/mm/damon/usage: update for schemes statistics
mm/damon/dbgfs: support all DAMOS stats
Docs/admin-guide/mm/damon/reclaim: document statistics parameters
mm/damon/reclaim: provide reclamation statistics
mm/damon/schemes: account how many times quota limit has exceeded
mm/damon/schemes: account scheme actions that successfully applied
mm/damon: remove a mistakenly added comment for a future feature
Docs/admin-guide/mm/damon/usage: update for kdamond_pid and (mk|rm)_contexts
Docs/admin-guide/mm/damon/usage: mention tracepoint at the beginning
Docs/admin-guide/mm/damon/usage: remove redundant information
Docs/admin-guide/mm/damon/usage: update for scheme quotas and watermarks
mm/damon: convert macro functions to static inline functions
mm/damon: modify damon_rand() macro to static inline function
mm/damon: move damon_rand() definition into damon.h
...
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>
Since commit 4064b98270 ("mm: allow VM_FAULT_RETRY for multiple
times") allowed VM_FAULT_RETRY for multiple times, the
FAULT_FLAG_ALLOW_RETRY bit of fault_flag will not be changed in the page
fault path, so the following check is no longer needed:
flags & FAULT_FLAG_ALLOW_RETRY
So just remove it.
[akpm@linux-foundation.org: coding style fixes]
Link: https://lkml.kernel.org/r/20211110123358.36511-1-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Kirill Shutemov <kirill@shutemov.name>
Cc: Peter Xu <peterx@redhat.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Presumably, arch/{parisc,s390,sh}/boot/compressed/Makefile copied
arch/x86/boot/compressed/Makefile, but vmlinux.bin.all-y is useless
here because it is the same as $(obj)/vmlinux.bin.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <n.schier@avm.de>
GZIP-compressed files end with 4 byte data that represents the size
of the original input. The decompressors (the self-extracting kernel)
exploit it to know the vmlinux size beforehand. To mimic the GZIP's
trailer, Kbuild provides cmd_{bzip2,lzma,lzo,lz4,xzkern,zstd22}.
Unfortunately these macros are used everywhere despite the appended
size data is only useful for the decompressors.
There is no guarantee that such hand-crafted trailers are safely ignored.
In fact, the kernel refuses compressed initramdfs with the garbage data.
That is why usr/Makefile overrides size_append to make it no-op.
To limit the use of such broken compressed files, this commit renames
the existing macros as follows:
cmd_bzip2 --> cmd_bzip2_with_size
cmd_lzma --> cmd_lzma_with_size
cmd_lzo --> cmd_lzo_with_size
cmd_lz4 --> cmd_lz4_with_size
cmd_xzkern --> cmd_xzkern_with_size
cmd_zstd22 --> cmd_zstd22_with_size
To keep the decompressors working, I updated the following Makefiles
accordingly:
arch/arm/boot/compressed/Makefile
arch/h8300/boot/compressed/Makefile
arch/mips/boot/compressed/Makefile
arch/parisc/boot/compressed/Makefile
arch/s390/boot/compressed/Makefile
arch/sh/boot/compressed/Makefile
arch/x86/boot/compressed/Makefile
I reused the current macro names for the normal usecases; they produce
the compressed data in the proper format.
I did not touch the following:
arch/arc/boot/Makefile
arch/arm64/boot/Makefile
arch/csky/boot/Makefile
arch/mips/boot/Makefile
arch/riscv/boot/Makefile
arch/sh/boot/Makefile
kernel/Makefile
This means those Makefiles will stop appending the size data.
I dropped the 'override size_append' hack from usr/Makefile.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <n.schier@avm.de>
Add the visible flag to the toc_stack variable to make it visible for
assembly code and to avoid a sparse warning.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Qemu currently supports up to 16 CPUs, so increase the default from 4 to 16.
Bload-o-meter shows only an increase of 800 bytes with this change.
Signed-off-by: Helge Deller <deller@gmx.de>
No need to have an own hpmc_stack. Just re-use the toc_stack of the
monarch CPU as either a TOC or a HPMC will happen at the same time.
This reduces the kernel memory footprint by 16k.
Signed-off-by: Helge Deller <deller@gmx.de>
Before this patch, the TOC code used a pre-allocated stack of 16kb for
each possible CPU. That space overhead was the reason why the TOC
feature wasn't enabled by default for 32-bit kernels.
This patch rewrites the TOC code to use a per-cpu stack. That way we use
much less memory now and as such we enable the TOC feature by default on
all kernels.
Additionally the dump of the registers and the stacktrace wasn't
serialized, which led to multiple CPUs printing the stack backtrace at
once which rendered the output unreadable.
Now the backtraces are nicely serialized by a lock.
Signed-off-by: Helge Deller <deller@gmx.de>
This patch fixes the following build error for source file
drivers/scsi/pcmcia/sym53c500_cs.c:
In file included from ./include/linux/bug.h:5,
from ./include/linux/cpumask.h:14,
from ./include/linux/mm_types_task.h:14,
from ./include/linux/mm_types.h:5,
from ./include/linux/buildid.h:5,
from ./include/linux/module.h:14,
from drivers/scsi/pcmcia/sym53c500_cs.c:42:
drivers/scsi/pcmcia/sym53c500_cs.c: In function ‘SYM53C500_intr’:
./arch/parisc/include/asm/bug.h:28:2: error: expected expression before ‘do’
28 | do { \
| ^~
./arch/parisc/include/asm/io.h:276:20: note: in expansion of macro ‘BUG’
276 | #define outb(x, y) BUG()
| ^~~
drivers/scsi/pcmcia/sym53c500_cs.c:124:19: note: in expansion of macro ‘outb’
124 | #define REG0(x) (outb(C4_IMG, (x) + CONFIG4))
| ^~~~
drivers/scsi/pcmcia/sym53c500_cs.c:362:2: note: in expansion of macro ‘REG0’
362 | REG0(port_base);
| ^~~~
Cc: James E.J. Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: linux-parisc@vger.kernel.org
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Helge Deller <deller@gmx.de>
Add a simplistic keyboard driver for usage of PDC I/O functions
with kgdb. This driver makes it possible to use KGDB with QEMU.
Signed-off-by: Helge Deller <deller@gmx.de>
The definitions for pdc_toc_pim_11 and pdc_toc_pim_20 are wrong since they
include an entry for a hversion field which doesn't exist in the specification.
Fix this and clean up some whitespaces so that the whole file will be in
sync with it's copy in the SeaBIOS-hppa sources.
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org # v5.16
This patch adds two new LWS routines - lws_atomic_xchg and lws_atomic_store.
These are simpler than the CAS routines. Currently, we use the CAS
routines for atomic stores. This is inefficient since it requires
both winning the spinlock and a successful CAS operation.
Change has been tested on c8000 and rp3440.
In v2, I moved the code to disble/enable page faults inside the spinlocks.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
The parisc architecture lacks general hardware support for compare and swap.
Particularly for userspace, it is difficult to implement software atomic
support. Page faults in critical regions can cause processes to sleep and
block the forward progress of other processes. Thus, it is essential that
page faults be disabled in critical regions. For performance reasons, we
also need to disable external interrupts in critical regions.
In order to do this, we need a mechanism to trigger COW breaks outside the
critical region. Fortunately, parisc has the "stbys,e" instruction. When
the leftmost byte of a word is addressed, this instruction triggers all
the exceptions of a normal store but it does not write to memory. Thus,
we can use it to trigger COW breaks outside the critical region without
modifying the data that is to be updated atomically.
COW breaks occur randomly. So even if we have priviously executed a "stbys,e"
instruction, we still need to disable pagefaults around the critical region.
If a fault occurs in the critical region, we return -EAGAIN. I had to add
a wrapper around _arch_futex_atomic_op_inuser() as I found in testing that
returning -EAGAIN caused problems for some processes even though it is
listed as a possible return value.
The patch implements the above. The code no longer attempts to sleep with
interrupts disabled and I haven't seen any stalls with the change.
I have attempted to merge common code and streamline the fast path. In the
futex code, we only compute the spinlock address once.
I eliminated some debug code in the original CAS routine that just made the
flow more complicated.
I don't clip the arguments when called from wide mode. As a result, the LWS
routines should work when called from 64-bit processes.
I defined TASK_PAGEFAULT_DISABLED offset for use in the lws_pagefault_disable
and lws_pagefault_enable macros.
Since we now disable interrupts on the gateway page where necessary, it
might be possible to allow processes to be scheduled when they are on the
gateway page.
Change has been tested on c8000 and rp3440. It improves glibc build and test
time by about 10%.
In v2, I removed the lws_atomic_xchg and and lws_atomic_store calls. I
also removed the bug fixes that were not directly related to this patch.
In v3, I removed the code to force interruptions from
arch_futex_atomic_op_inuser(). It is always called with page faults
disabled, so this code had no effect.
In v4, I fixed a typo in depi_safe line.
In v5, I moved the code to disable/enable page faults inside the spinlocks.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
In debugging kernel panics, I believe it is useful to know what type
of page fault caused the termination. "Bad Address" is too vague.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
It is dangerous to call faulthandler_disabled() when user_mode(regs)
is true. The task pagefault_disabled counter is racy and it is not
updated atomically on parisc. As a result, calling faulthandler_disabled()
may cause erroneous termination.
We now handle execption fixups and termination when user_mode(regs) is
false in handle_interruption(). Thus, we can just remove the
faulthandler_disabled() check from do_page_fault().
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
Use register r29 instead of register r8 to signal faults when accessing
user memory. In case of faults, the fixup routine will store -EFAULT in
this register.
This change saves up to 752 bytes on a 32bit kernel, partly because the
compiler doesn't need to save and restore the old r8 value on the stack.
bloat-o-meter results for usage with r29 register:
add/remove: 0/0 grow/shrink: 23/86 up/down: 228/-980 (-752)
bloat-o-meter results for usage with r28 register:
add/remove: 0/0 grow/shrink: 28/83 up/down: 296/-956 (-660)
Signed-off-by: Helge Deller <deller@gmx.de>
In handle_interruption(), we call faulthandler_disabled() to check whether the
fault handler is not disabled. If the fault handler is disabled, we immediately
call do_page_fault(). It then calls faulthandler_disabled(). If disabled,
do_page_fault() attempts to fixup the exception by jumping to no_context:
no_context:
if (!user_mode(regs) && fixup_exception(regs)) {
return;
}
parisc_terminate("Bad Address (null pointer deref?)", regs, code, address);
Apart from the error messages, the two blocks of code perform the same
function.
We can avoid two calls to faulthandler_disabled() by a simple revision
to the code in handle_interruption().
Note: I didn't try to fix the formatting of this code block.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
While working on the rewrite to the light-weight syscall and futex code, I
experimented with using a hash index based on the user physical address of
atomic variable. This exposed two problems with the lpa and lpa_user defines.
Because of the copy instruction, the pa argument needs to be an early clobber
argument. This prevents gcc from allocating the va and pa arguments to the same
register.
Secondly, the lpa instruction can cause a page fault so we need to catch
exceptions.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Fixes: 116d753308 ("parisc: Use lpa instruction to load physical addresses in driver code")
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org # v5.2+
The depi instruction is similar to the extru instruction on 64-bit machines.
It leaves the most-significant 32 bits of the target register in an undefined
state. On 64-bit machines, the macro uses depdi to perform safe deposits in
the least-significant 32 bits.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
