- Add HOTPLUG_SMT support (/sys/devices/system/cpu/smt) and honour the
configured SMT state when hotplugging CPUs into the system.
- Combine final TLB flush and lazy TLB mm shootdown IPIs when using the Radix
MMU to avoid a broadcast TLBIE flush on exit.
- Drop the exclusion between ptrace/perf watchpoints, and drop the now unused
associated arch hooks.
- Add support for the "nohlt" command line option to disable CPU idle.
- Add support for -fpatchable-function-entry for ftrace, with GCC >= 13.1.
- Rework memory block size determination, and support 256MB size on systems
with GPUs that have hotpluggable memory.
- Various other small features and fixes.
Thanks to: Andrew Donnellan, Aneesh Kumar K.V, Arnd Bergmann, Athira Rajeev,
Benjamin Gray, Christophe Leroy, Frederic Barrat, Gautam Menghani, Geoff Levand,
Hari Bathini, Immad Mir, Jialin Zhang, Joel Stanley, Jordan Niethe, Justin
Stitt, Kajol Jain, Kees Cook, Krzysztof Kozlowski, Laurent Dufour, Liang He,
Linus Walleij, Mahesh Salgaonkar, Masahiro Yamada, Michal Suchanek, Nageswara
R Sastry, Nathan Chancellor, Nathan Lynch, Naveen N Rao, Nicholas Piggin, Nick
Desaulniers, Omar Sandoval, Randy Dunlap, Reza Arbab, Rob Herring, Russell
Currey, Sourabh Jain, Thomas Gleixner, Trevor Woerner, Uwe Kleine-König, Vaibhav
Jain, Xiongfeng Wang, Yuan Tan, Zhang Rui, Zheng Zengkai.
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Merge tag 'powerpc-6.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman:
- Add HOTPLUG_SMT support (/sys/devices/system/cpu/smt) and honour the
configured SMT state when hotplugging CPUs into the system
- Combine final TLB flush and lazy TLB mm shootdown IPIs when using the
Radix MMU to avoid a broadcast TLBIE flush on exit
- Drop the exclusion between ptrace/perf watchpoints, and drop the now
unused associated arch hooks
- Add support for the "nohlt" command line option to disable CPU idle
- Add support for -fpatchable-function-entry for ftrace, with GCC >=
13.1
- Rework memory block size determination, and support 256MB size on
systems with GPUs that have hotpluggable memory
- Various other small features and fixes
Thanks to Andrew Donnellan, Aneesh Kumar K.V, Arnd Bergmann, Athira
Rajeev, Benjamin Gray, Christophe Leroy, Frederic Barrat, Gautam
Menghani, Geoff Levand, Hari Bathini, Immad Mir, Jialin Zhang, Joel
Stanley, Jordan Niethe, Justin Stitt, Kajol Jain, Kees Cook, Krzysztof
Kozlowski, Laurent Dufour, Liang He, Linus Walleij, Mahesh Salgaonkar,
Masahiro Yamada, Michal Suchanek, Nageswara R Sastry, Nathan Chancellor,
Nathan Lynch, Naveen N Rao, Nicholas Piggin, Nick Desaulniers, Omar
Sandoval, Randy Dunlap, Reza Arbab, Rob Herring, Russell Currey, Sourabh
Jain, Thomas Gleixner, Trevor Woerner, Uwe Kleine-König, Vaibhav Jain,
Xiongfeng Wang, Yuan Tan, Zhang Rui, and Zheng Zengkai.
* tag 'powerpc-6.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (135 commits)
macintosh/ams: linux/platform_device.h is needed
powerpc/xmon: Reapply "Relax frame size for clang"
powerpc/mm/book3s64: Use 256M as the upper limit with coherent device memory attached
powerpc/mm/book3s64: Fix build error with SPARSEMEM disabled
powerpc/iommu: Fix notifiers being shared by PCI and VIO buses
powerpc/mpc5xxx: Add missing fwnode_handle_put()
powerpc/config: Disable SLAB_DEBUG_ON in skiroot
powerpc/pseries: Remove unused hcall tracing instruction
powerpc/pseries: Fix hcall tracepoints with JUMP_LABEL=n
powerpc: dts: add missing space before {
powerpc/eeh: Use pci_dev_id() to simplify the code
powerpc/64s: Move CPU -mtune options into Kconfig
powerpc/powermac: Fix unused function warning
powerpc/pseries: Rework lppaca_shared_proc() to avoid DEBUG_PREEMPT
powerpc: Don't include lppaca.h in paca.h
powerpc/pseries: Move hcall_vphn() prototype into vphn.h
powerpc/pseries: Move VPHN constants into vphn.h
cxl: Drop unused detach_spa()
powerpc: Drop zalloc_maybe_bootmem()
powerpc/powernv: Use struct opal_prd_msg in more places
...
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Merge tag 'integrity-v6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity
Pull integrity subsystem updates from Mimi Zohar:
- With commit 099f26f22f ("integrity: machine keyring CA
configuration") certificates may be loaded onto the IMA keyring,
directly or indirectly signed by keys on either the "builtin" or the
"machine" keyrings.
With the ability for the system/machine owner to sign the IMA policy
itself without needing to recompile the kernel, update the IMA
architecture specific policy rules to require the IMA policy itself
be signed.
[ As commit 099f26f22f was upstreamed in linux-6.4, updating the
IMA architecture specific policy now to require signed IMA policies
may break userspace expectations. ]
- IMA only checked the file data hash was not on the system blacklist
keyring for files with an appended signature (e.g. kernel modules,
Power kernel image).
Check all file data hashes regardless of how it was signed
- Code cleanup, and a kernel-doc update
* tag 'integrity-v6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
kexec_lock: Replace kexec_mutex() by kexec_lock() in two comments
ima: require signed IMA policy when UEFI secure boot is enabled
integrity: Always reference the blacklist keyring with appraisal
ima: Remove deprecated IMA_TRUSTED_KEYRING Kconfig
- allow dynamic sizing of the swiotlb buffer, to cater for secure
virtualization workloads that require all I/O to be bounce buffered
(Petr Tesarik)
- move a declaration to a header (Arnd Bergmann)
- check for memory region overlap in dma-contiguous (Binglei Wang)
- remove the somewhat dangerous runtime swiotlb-xen enablement and
unexport is_swiotlb_active (Christoph Hellwig, Juergen Gross)
- per-node CMA improvements (Yajun Deng)
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Merge tag 'dma-mapping-6.6-2023-08-29' of git://git.infradead.org/users/hch/dma-mapping
Pull dma-maping updates from Christoph Hellwig:
- allow dynamic sizing of the swiotlb buffer, to cater for secure
virtualization workloads that require all I/O to be bounce buffered
(Petr Tesarik)
- move a declaration to a header (Arnd Bergmann)
- check for memory region overlap in dma-contiguous (Binglei Wang)
- remove the somewhat dangerous runtime swiotlb-xen enablement and
unexport is_swiotlb_active (Christoph Hellwig, Juergen Gross)
- per-node CMA improvements (Yajun Deng)
* tag 'dma-mapping-6.6-2023-08-29' of git://git.infradead.org/users/hch/dma-mapping:
swiotlb: optimize get_max_slots()
swiotlb: move slot allocation explanation comment where it belongs
swiotlb: search the software IO TLB only if the device makes use of it
swiotlb: allocate a new memory pool when existing pools are full
swiotlb: determine potential physical address limit
swiotlb: if swiotlb is full, fall back to a transient memory pool
swiotlb: add a flag whether SWIOTLB is allowed to grow
swiotlb: separate memory pool data from other allocator data
swiotlb: add documentation and rename swiotlb_do_find_slots()
swiotlb: make io_tlb_default_mem local to swiotlb.c
swiotlb: bail out of swiotlb_init_late() if swiotlb is already allocated
dma-contiguous: check for memory region overlap
dma-contiguous: support numa CMA for specified node
dma-contiguous: support per-numa CMA for all architectures
dma-mapping: move arch_dma_set_mask() declaration to header
swiotlb: unexport is_swiotlb_active
x86: always initialize xen-swiotlb when xen-pcifront is enabling
xen/pci: add flag for PCI passthrough being possible
("refactor Kconfig to consolidate KEXEC and CRASH options").
- kernel.h slimming work from Andy Shevchenko ("kernel.h: Split out a
couple of macros to args.h").
- gdb feature work from Kuan-Ying Lee ("Add GDB memory helper
commands").
- vsprintf inclusion rationalization from Andy Shevchenko
("lib/vsprintf: Rework header inclusions").
- Switch the handling of kdump from a udev scheme to in-kernel handling,
by Eric DeVolder ("crash: Kernel handling of CPU and memory hot
un/plug").
- Many singleton patches to various parts of the tree
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Merge tag 'mm-nonmm-stable-2023-08-28-22-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull non-MM updates from Andrew Morton:
- An extensive rework of kexec and crash Kconfig from Eric DeVolder
("refactor Kconfig to consolidate KEXEC and CRASH options")
- kernel.h slimming work from Andy Shevchenko ("kernel.h: Split out a
couple of macros to args.h")
- gdb feature work from Kuan-Ying Lee ("Add GDB memory helper
commands")
- vsprintf inclusion rationalization from Andy Shevchenko
("lib/vsprintf: Rework header inclusions")
- Switch the handling of kdump from a udev scheme to in-kernel
handling, by Eric DeVolder ("crash: Kernel handling of CPU and memory
hot un/plug")
- Many singleton patches to various parts of the tree
* tag 'mm-nonmm-stable-2023-08-28-22-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (81 commits)
document while_each_thread(), change first_tid() to use for_each_thread()
drivers/char/mem.c: shrink character device's devlist[] array
x86/crash: optimize CPU changes
crash: change crash_prepare_elf64_headers() to for_each_possible_cpu()
crash: hotplug support for kexec_load()
x86/crash: add x86 crash hotplug support
crash: memory and CPU hotplug sysfs attributes
kexec: exclude elfcorehdr from the segment digest
crash: add generic infrastructure for crash hotplug support
crash: move a few code bits to setup support of crash hotplug
kstrtox: consistently use _tolower()
kill do_each_thread()
nilfs2: fix WARNING in mark_buffer_dirty due to discarded buffer reuse
scripts/bloat-o-meter: count weak symbol sizes
treewide: drop CONFIG_EMBEDDED
lockdep: fix static memory detection even more
lib/vsprintf: declare no_hash_pointers in sprintf.h
lib/vsprintf: split out sprintf() and friends
kernel/fork: stop playing lockless games for exe_file replacement
adfs: delete unused "union adfs_dirtail" definition
...
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Merge tag 'v6.6-vfs.fchmodat2' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull fchmodat2 system call from Christian Brauner:
"This adds the fchmodat2() system call. It is a revised version of the
fchmodat() system call, adding a missing flag argument. Support for
both AT_SYMLINK_NOFOLLOW and AT_EMPTY_PATH are included.
Adding this system call revision has been a longstanding request but
so far has always fallen through the cracks. While the kernel
implementation of fchmodat() does not have a flag argument the libc
provided POSIX-compliant fchmodat(3) version does. Both glibc and musl
have to implement a workaround in order to support AT_SYMLINK_NOFOLLOW
(see [1] and [2]).
The workaround is brittle because it relies not just on O_PATH and
O_NOFOLLOW semantics and procfs magic links but also on our rather
inconsistent symlink semantics.
This gives userspace a proper fchmodat2() system call that libcs can
use to properly implement fchmodat(3) and allows them to get rid of
their hacks. In this case it will immediately benefit them as the
current workaround is already defunct because of aformentioned
inconsistencies.
In addition to AT_SYMLINK_NOFOLLOW, give userspace the ability to use
AT_EMPTY_PATH with fchmodat2(). This is already possible with
fchownat() so there's no reason to not also support it for
fchmodat2().
The implementation is simple and comes with selftests. Implementation
of the system call and wiring up the system call are done as separate
patches even though they could arguably be one patch. But in case
there are merge conflicts from other system call additions it can be
beneficial to have separate patches"
Link: https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/fchmodat.c;h=17eca54051ee28ba1ec3f9aed170a62630959143;hb=a492b1e5ef7ab50c6fdd4e4e9879ea5569ab0a6c#l35 [1]
Link: https://git.musl-libc.org/cgit/musl/tree/src/stat/fchmodat.c?id=718f363bc2067b6487900eddc9180c84e7739f80#n28 [2]
* tag 'v6.6-vfs.fchmodat2' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
selftests: fchmodat2: remove duplicate unneeded defines
fchmodat2: add support for AT_EMPTY_PATH
selftests: Add fchmodat2 selftest
arch: Register fchmodat2, usually as syscall 452
fs: Add fchmodat2()
Non-functional cleanup of a "__user * filename"
fail_iommu_setup() registers the fail_iommu_bus_notifier struct to both
PCI and VIO buses. struct notifier_block is a linked list node, so this
causes any notifiers later registered to either bus type to also be
registered to the other since they share the same node.
This causes issues in (at least) the vgaarb code, which registers a
notifier for PCI buses. pci_notify() ends up being called on a vio
device, converted with to_pci_dev() even though it's not a PCI device,
and finally makes a bad access in vga_arbiter_add_pci_device() as
discovered with KASAN:
BUG: KASAN: slab-out-of-bounds in vga_arbiter_add_pci_device+0x60/0xe00
Read of size 4 at addr c000000264c26fdc by task swapper/0/1
Call Trace:
dump_stack_lvl+0x1bc/0x2b8 (unreliable)
print_report+0x3f4/0xc60
kasan_report+0x244/0x698
__asan_load4+0xe8/0x250
vga_arbiter_add_pci_device+0x60/0xe00
pci_notify+0x88/0x444
notifier_call_chain+0x104/0x320
blocking_notifier_call_chain+0xa0/0x140
device_add+0xac8/0x1d30
device_register+0x58/0x80
vio_register_device_node+0x9ac/0xce0
vio_bus_scan_register_devices+0xc4/0x13c
__machine_initcall_pseries_vio_device_init+0x94/0xf0
do_one_initcall+0x12c/0xaa8
kernel_init_freeable+0xa48/0xba8
kernel_init+0x64/0x400
ret_from_kernel_thread+0x5c/0x64
Fix this by creating separate notifier_block structs for each bus type.
Fixes: d6b9a81b2a ("powerpc: IOMMU fault injection")
Reported-by: Nageswara R Sastry <rnsastry@linux.ibm.com>
Signed-off-by: Russell Currey <ruscur@russell.cc>
Tested-by: Nageswara R Sastry <rnsastry@linux.ibm.com>
Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>
[mpe: Add #ifdef to fix CONFIG_IBMVIO=n build]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230322035322.328709-1-ruscur@russell.cc
The only callers of zalloc_maybe_bootmem() are PCI setup routines. These
used to be called early during boot before slab setup, and also during
runtime due to hotplug.
But commit 5537fcb319 ("powerpc/pci: Add ppc_md.discover_phbs()")
moved the boot-time calls later, after slab setup, meaning there's no
longer any need for zalloc_maybe_bootmem(), kzalloc() can be used in all
cases.
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230823055430.752550-1-mpe@ellerman.id.au
GCC v13.1 updated support for -fpatchable-function-entry on ppc64le to
emit nops after the local entry point, rather than before it. This
allows us to use this in the kernel for ftrace purposes. A new script is
added under arch/powerpc/tools/ to help detect if nops are emitted after
the function local entry point, or before the global entry point.
With -fpatchable-function-entry, we no longer have the profiling
instructions generated at function entry, so we only need to validate
the presence of two nops at the ftrace location in ftrace_init_nop(). We
patch the preceding instruction with 'mflr r0' to match the
-mprofile-kernel ABI for subsequent ftrace use.
This changes the profiling instructions used on ppc32. The default -pg
option emits an additional 'stw' instruction after 'mflr r0' and before
the branch to _mcount 'bl _mcount'. This is very similar to the original
-mprofile-kernel implementation on ppc64le, where an additional 'std'
instruction was used to save LR to its save location in the caller's
stackframe. Subsequently, this additional store was removed in later
compiler versions for performance reasons. The same reasons apply for
ppc32 so we only patch in a 'mflr r0'.
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/68586d22981a2c3bb45f27a2b621173d10a7d092.1687166935.git.naveen@kernel.org
Implement ftrace_replace_code() to consolidate logic from the different
ftrace patching routines: ftrace_make_nop(), ftrace_make_call() and
ftrace_modify_call(). Note that ftrace_make_call() is still required
primarily to handle patching modules during their load time. The other
two routines should no longer be called.
This lays the groundwork to enable better control in patching ftrace
locations, including the ability to nop-out preceding profiling
instructions when ftrace is disabled.
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/c28f852225646b0561bbf3c1d22d03f041ace8e0.1687166935.git.naveen@kernel.org
Now that we validate the ftrace location during initialization in
ftrace_init_nop(), we can simplify ftrace_modify_call() to patch-in the
updated branch instruction without worrying about the instructions
surrounding the ftrace location. Note that we continue to ensure we
have the expected branch instruction at the ftrace location before
patching it with the updated branch destination.
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/06275720939f8ee4c2f61c9e9a3e89b1fa3c441d.1687166935.git.naveen@kernel.org
Now that we validate the ftrace location during initialization in
ftrace_init_nop(), we can simplify ftrace_make_call() to replace the nop
without worrying about the instructions surrounding the ftrace location.
Note that we continue to ensure that we have a nop at the ftrace
location before patching it.
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/2d28866d2f556488a663981abe5621511efb207b.1687166935.git.naveen@kernel.org
Now that we validate the ftrace location during initialization in
ftrace_init_nop(), we can simplify ftrace_make_nop() to patch-in the nop
without worrying about the instructions surrounding the ftrace location.
Note that we continue to ensure that we have a bl to
ftrace_[regs_]caller at the ftrace location before nop-ing it out.
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/e12ccbf28c50c3a07fb614f4d392e55f7098a729.1687166935.git.naveen@kernel.org
Currently, we validate instructions around the ftrace location every
time we have to enable/disable ftrace. Introduce ftrace_init_nop() to
instead perform all the validation during ftrace initialization. This
allows us to simply patch the necessary instructions during
enabling/disabling ftrace.
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/f373684081e8e98be09b7f44d2d93069768324dc.1687166935.git.naveen@kernel.org
Commit 67361cf807 ("powerpc/ftrace: Handle large kernel configs")
added ftrace support for ppc64 kernel images with a text section larger
than 32MB. The patch did two things:
1. Add stubs at the end of .text to branch into ftrace_[regs_]caller for
functions that were out of branch range.
2. Re-purpose linker-generated long branches to _mcount to instead branch
to ftrace_[regs_]caller.
Before that, we only supported kernel .text up to ~32MB. With the above,
we now support up to ~96MB:
- The first 32MB of kernel text can branch directly into
ftrace_[regs_]caller since that symbol is usually at the beginning.
- The modified long_branch from (2) above is used by the next 32MB of
kernel text.
- The next 32MB of kernel text can use the stub at the end of text to
branch back to ftrace_[regs_]caller.
While re-purposing the long branch works in practice, it still restricts
ftrace to kernel text up to ~96MB. The stub at the end of kernel text
from (1) already enables us to extend ftrace support for kernel text
up to 64MB, which fulfils the original requirement. Further, once we
switch to -fpatchable-function-entry, there will not be a long branch
that we can use.
Stop re-purposing the linker-generated long branches for ftrace to
simplify the code. If there are good reasons to support ftrace on
kernels beyond 64MB, we can consider adding support by using
-fpatchable-function-entry.
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/33fa3be97f8e1f2171254ef2e1b0d5c8836c11fd.1687166935.git.naveen@kernel.org
ftrace_low.S has just the _mcount stub and return_to_handler(). Merge
this back into ftrace_mprofile.S and ftrace_64_pg.S to keep all ftrace
code together, and to allow those to evolve independently.
ftrace_mprofile.S is also not an entirely accurate name since this also
holds ppc32 code. This will be all the more incorrect once support for
-fpatchable-function-entry is added. Rename files here to more
accurately describe the code:
- ftrace_mprofile.S is renamed to ftrace_entry.S
- ftrace_pg.c is renamed to ftrace_64_pg.c
- ftrace_64_pg.S is rename to ftrace_64_pg_entry.S
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/b900c9a8bba9d6c3c295e0f99886acf3e5bf6f7b.1687166935.git.naveen@kernel.org
Commit 67361cf807 ("powerpc/ftrace: Handle large kernel configs")
added ftrace support for ppc64 kernel images with a text section larger
than 32MB. The approach itself isn't specific to ppc64, so extend the
same to also work on ppc32.
While at it, reduce the space reserved for the stub from 64 bytes to 32
bytes since the different stub variants are all less than 8
instructions.
To reduce use of #ifdef, a stub implementation is provided for
kernel_toc_address() and -SZ_2G is cast to 'long long' to prevent
errors on ppc32.
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/9fa3258cbb9105cf8a0a8135214d44ffbc75fe84.1687166935.git.naveen@kernel.org
Instead of keying off DYNAMIC_FTRACE_WITH_REGS, use FTRACE_REGS_ADDR to
identify the proper ftrace trampoline address to use.
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/6045a280a57a7ea937a5bb13ccac747026dbfb07.1687166935.git.naveen@kernel.org
Since we now support DYNAMIC_FTRACE_WITH_ARGS across ppc32 and ppc64
ELFv2, we can simplify function_graph tracer support code in ftrace.c
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/4dc92c4b1ed444dc62b748ae7327acdb9e096864.1687166935.git.naveen@kernel.org
ELFv1 support is deprecated and on the way out. Pre -mprofile-kernel
ftrace support (-pg only) is very limited and is retained primarily for
clang builds. It won't be necessary once clang lands support for
-fpatchable-function-entry.
Copy the existing ftrace code supporting these into ftrace_pg.c.
ftrace.c can then be refactored and enhanced with a focus on ppc32 and
ppc64 ELFv2.
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/1eb6cc6c3141ddb77a2a25f8a9e83d83ff312b02.1687166935.git.naveen@kernel.org
The APIs that allow backtracing across CPUs have always had a way to
exclude the current CPU. This convenience means callers didn't need to
find a place to allocate a CPU mask just to handle the common case.
Let's extend the API to take a CPU ID to exclude instead of just a
boolean. This isn't any more complex for the API to handle and allows the
hardlockup detector to exclude a different CPU (the one it already did a
trace for) without needing to find space for a CPU mask.
Arguably, this new API also encourages safer behavior. Specifically if
the caller wants to avoid tracing the current CPU (maybe because they
already traced the current CPU) this makes it more obvious to the caller
that they need to make sure that the current CPU ID can't change.
[akpm@linux-foundation.org: fix trigger_allbutcpu_cpu_backtrace() stub]
Link: https://lkml.kernel.org/r/20230804065935.v4.1.Ia35521b91fc781368945161d7b28538f9996c182@changeid
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: kernel test robot <lkp@intel.com>
Cc: Lecopzer Chen <lecopzer.chen@mediatek.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Pingfan Liu <kernelfans@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Invoke ibm,os-term call with rtas_call_unlocked(), without using the
RTAS spinlock, to avoid deadlock in the unlikely event of a machine
crash while making an RTAS call.
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Reviewed-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230609071404.425529-1-hbathini@linux.ibm.com
In case fadump_reserve_mem() fails to reserve memory, the
reserve_dump_area_size variable will retain the reserve area size. This
will lead to /sys/kernel/fadump/mem_reserved node displaying an incorrect
memory reserved by fadump.
To fix this problem, reserve dump area size variable is set to 0 if fadump
failed to reserve memory.
Fixes: 8255da95e5 ("powerpc/fadump: release all the memory above boot memory size")
Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Acked-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230704050715.203581-1-sourabhjain@linux.ibm.com
Building ppc40x_defconfig throws the following error:
CC arch/powerpc/kernel/traps.o
arch/powerpc/kernel/traps.c:2232:29: warning: no previous prototype for 'WatchdogHandler' [-Wmissing-prototypes]
2232 | void __attribute__ ((weak)) WatchdogHandler(struct pt_regs *regs)
| ^~~~~~~~~~~~~~~
This function was imported by commit 14cf11af6c ("powerpc: Merge
enough to start building in arch/powerpc.") as a weak function but
never defined and/or called outside traps.c
As it has only one caller fold it inside its caller and remove it.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/38fe1078eb403eef74dc8f29387636fd7ecdf43c.1692276041.git.christophe.leroy@csgroup.eu
With hardened usercopy enabled (CONFIG_HARDENED_USERCOPY=y), using the
/proc/powerpc/rtas/firmware_update interface to prepare a system
firmware update yields a BUG():
kernel BUG at mm/usercopy.c:102!
Oops: Exception in kernel mode, sig: 5 [#1]
LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
Modules linked in:
CPU: 0 PID: 2232 Comm: dd Not tainted 6.5.0-rc3+ #2
Hardware name: IBM,8408-E8E POWER8E (raw) 0x4b0201 0xf000004 of:IBM,FW860.50 (SV860_146) hv:phyp pSeries
NIP: c0000000005991d0 LR: c0000000005991cc CTR: 0000000000000000
REGS: c0000000148c76a0 TRAP: 0700 Not tainted (6.5.0-rc3+)
MSR: 8000000000029033 <SF,EE,ME,IR,DR,RI,LE> CR: 24002242 XER: 0000000c
CFAR: c0000000001fbd34 IRQMASK: 0
[ ... GPRs omitted ... ]
NIP usercopy_abort+0xa0/0xb0
LR usercopy_abort+0x9c/0xb0
Call Trace:
usercopy_abort+0x9c/0xb0 (unreliable)
__check_heap_object+0x1b4/0x1d0
__check_object_size+0x2d0/0x380
rtas_flash_write+0xe4/0x250
proc_reg_write+0xfc/0x160
vfs_write+0xfc/0x4e0
ksys_write+0x90/0x160
system_call_exception+0x178/0x320
system_call_common+0x160/0x2c4
The blocks of the firmware image are copied directly from user memory
to objects allocated from flash_block_cache, so flash_block_cache must
be created using kmem_cache_create_usercopy() to mark it safe for user
access.
Fixes: 6d07d1cd30 ("usercopy: Restrict non-usercopy caches to size 0")
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
[mpe: Trim and indent oops]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230810-rtas-flash-vs-hardened-usercopy-v2-1-dcf63793a938@linux.ibm.com
objtool reports the following warning:
arch/powerpc/kernel/ptrace/ptrace-view.o: warning: objtool:
gpr32_set_common+0x23c (.text+0x860): redundant UACCESS disable
gpr32_set_common() conditionally opens and closes UACCESS based on
whether kbuf pointer is NULL or not. This is wackelig.
Split gpr32_set_common() in two fonctions, one for user one for
kernel.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
[mpe: Fix oops in gpr32_set_common_user() due to NULL kbuf]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/b8d6ae4483fcfd17524e79d803c969694a85cc02.1687428075.git.christophe.leroy@csgroup.eu
ptrace and perf watchpoints were considered incompatible in
commit 29da4f91c0 ("powerpc/watchpoint: Don't allow concurrent perf
and ptrace events"), but the logic in that commit doesn't really apply.
Ptrace doesn't automatically single step; the ptracer must request this
explicitly. And the ptracer can do so regardless of whether a
ptrace/perf watchpoint triggered or not: it could single step every
instruction if it wanted to. Whatever stopped the ptracee before
executing the instruction that would trigger the perf watchpoint is no
longer relevant by this point.
To get correct behaviour when perf and ptrace are watching the same
data we must ignore the perf watchpoint. After all, ptrace has
before-execute semantics, and perf is after-execute, so perf doesn't
actually care about the watchpoint trigger at this point in time.
Pausing before execution does not mean we will actually end up executing
the instruction.
Importantly though, we don't remove the perf watchpoint yet. This is
key.
The ptracer is free to do whatever it likes right now. E.g., it can
continue the process, single step. or even set the child PC somewhere
completely different.
If it does try to execute the instruction though, without reinserting
the watchpoint (in which case we go back to the start of this example),
the perf watchpoint would immediately trigger. This time there is no
ptrace watchpoint, so we can safely perform a single step and increment
the perf counter. Upon receiving the single step exception, the existing
code already handles propagating or consuming it based on whether
another subsystem (e.g. ptrace) requested a single step. Again, this is
needed with or without perf/ptrace exclusion, because ptrace could be
single stepping this instruction regardless of if a watchpoint is
involved.
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230801011744.153973-6-bgray@linux.ibm.com
We only remove watchpoints when they have the perf_single_step flag set,
so we can reinsert them during the first iteration.
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230801011744.153973-5-bgray@linux.ibm.com
There is a bug in the current watchpoint tracking logic, where the
teardown in arch_unregister_hw_breakpoint() uses bp->ctx->task, which it
does not have a reference of and parallel threads may be in the process
of destroying. This was partially addressed in commit fb822e6076
("powerpc/hw_breakpoint: Fix oops when destroying hw_breakpoint event"),
but the underlying issue of accessing a struct member in an unknown
state still remained. Syzkaller managed to trigger a null pointer
derefernce due to the race between the task destructor and checking the
pointer and dereferencing it in the loop.
While this null pointer dereference could be fixed by using READ_ONCE
to access the task up front, that just changes the error to manipulating
possbily freed memory.
Instead, the breakpoint logic needs to be reworked to remove any
dependency on a context or task struct during breakpoint removal.
The reason we have this currently is to clear thread.last_hit_ubp. This
member is used to differentiate the perf DAWR single-step sequence from
other causes of single-step, such as userspace just calling
ptrace(PTRACE_SINGLESTEP, ...). We need to differentiate them because,
when the single step interrupt is received, we need to know whether to
re-insert the DAWR breakpoint (perf) or not (ptrace / other).
arch_unregister_hw_breakpoint() needs to clear this information to
prevent dangling pointers to possibly freed memory. These pointers are
dereferenced in single_step_dabr_instruction() without a way to check
their validity.
This patch moves the tracking of this information to the breakpoint
itself. This means we no longer have to do anything special to clean up.
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230801011744.153973-4-bgray@linux.ibm.com
info is cheap to retrieve, and is likely optimised by the compiler
anyway. On the other hand, propagating it across the functions makes it
possible to be inconsistent and adds needless complexity.
Remove it, and invoke counter_arch_bp() when we need to work with it.
As we don't persist it, we just use the local bp array to track whether
we are ignoring a breakpoint.
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230801011744.153973-3-bgray@linux.ibm.com
The behaviour of the thread_change_pc() function is a bit cryptic
without being more familiar with how the watchpoint logic handles
perf's after-execute semantics.
Expand the comment to explain why we can re-insert the breakpoint and
unset the perf_single_step flag.
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230801011744.153973-2-bgray@linux.ibm.com
Commit ddb5cdbafa ("kbuild: generate KSYMTAB entries by modpost")
deprecated <asm/export.h>, which is now a wrapper of <linux/export.h>.
Replace #include <asm/export.h> with #include <linux/export.h>.
After all the <asm/export.h> lines are converted, <asm/export.h> and
<asm-generic/export.h> will be removed.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
[mpe: Fixup selftests that stub asm/export.h]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230806150954.394189-2-masahiroy@kernel.org
There is no EXPORT_SYMBOL line there, hence #include <asm/export.h>
is unneeded.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230806150954.394189-1-masahiroy@kernel.org
Add support for HOTPLUG_SMT, which enables the generic sysfs SMT support
files in /sys/devices/system/cpu/smt, as well as the "nosmt" boot
parameter.
Implement the recently added hooks to allow partial SMT states, allow
any number of threads per core.
Tie the config symbol to HOTPLUG_CPU, which enables it on the major
platforms that support SMT. If there are other platforms that want the
SMT support that can be tweaked in future.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
[ldufour: remove topology_smt_supported]
[ldufour: remove topology_smt_threads_supported]
[ldufour: select CONFIG_SMT_NUM_THREADS_DYNAMIC]
[ldufour: update kernel-parameters.txt]
Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>
Link: https://msgid.link/20230705145143.40545-10-ldufour@linux.ibm.com
There are a few warnings in powerpc64 defconfig builds after -Wmissing-prototypes
gets promoted from W=1 to the default warning set:
arch/powerpc/mm/book3s64/pgtable.c:422:6: error: no previous prototype for 'arch_report_meminfo' [-Werror=missing-prototypes]
arch/powerpc/platforms/cell/ras.c:275:5: error: no previous prototype for 'cbe_sysreset_hack' [-Werror=missing-prototypes]
arch/powerpc/platforms/cell/spu_manage.c:29:21: error: no previous prototype for 'spu_devnode' [-Werror=missing-prototypes]
arch/powerpc/platforms/pasemi/time.c:12:17: error: no previous prototype for 'pas_get_boot_time' [-Werror=missing-prototypes]
arch/powerpc/platforms/powermac/feature.c:1532:13: error: no previous prototype for 'g5_phy_disable_cpu1' [-Werror=missing-prototypes]
arch/powerpc/platforms/86xx/pic.c:28:13: error: no previous prototype for 'mpc86xx_init_irq' [-Werror=missing-prototypes]
drivers/pci/pci-sysfs.c:936:13: error: no previous prototype for 'pci_adjust_legacy_attr' [-Werror=missing-prototypes]
Address these by including the right header files or marking the
functions static. The audit.c one is a bit tricky since compat_audit.h
cannot include regular kernel headers tht have conflicting types on
32-bit powerpc.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
[mpe: Drop change to __vmemmap_free() which only exists in mm]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230727122720.2558065-1-arnd@kernel.org
The DT of_device.h and of_platform.h date back to the separate
of_platform_bus_type before it as merged into the regular platform bus.
As part of that merge prepping Arm DT support 13 years ago, they
"temporarily" include each other. They also include platform_device.h
and of.h. As a result, there's a pretty much random mix of those include
files used throughout the tree. In order to detangle these headers and
replace the implicit includes with struct declarations, users need to
explicitly include the correct includes.
Signed-off-by: Rob Herring <robh@kernel.org>
[mpe: Fixup maple/setup.c which needs platform_device]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230724210247.778034-1-robh@kernel.org
init_mm mm_cpumask and context.active_cpus is not maintained at boot
and hotplug. This seems to be harmless because init_mm does not have a
userspace and so never gets user TLBs flushed, but it looks odd and it
prevents some sanity checks being added.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230524060821.148015-2-npiggin@gmail.com
On book3s/32 KUAP is performed at segment level. At the moment,
when enabling userspace access, only current segment is modified.
Then if a write is performed on another user segment, a fault is
taken and all other user segments get enabled for userspace
access. This then require special attention when disabling
userspace access.
Having a userspace write access crossing a segment boundary is
unlikely. Having a userspace write access crossing a segment boundary
back and forth is even more unlikely. So, instead of enabling
userspace access on all segments when a write fault occurs, just
change which segment has userspace access enabled in order to
eliminate the case when more than one segment has userspace access
enabled. That simplifies userspace access deactivation.
There is however a corner case which is even more unlikely but has
to be handled anyway: an unaligned access which is crossing a
segment boundary. That would definitely require at least having
userspace access enabled on the two segments. To avoid complicating
the likely case for a so unlikely happening, handle such situation
like an alignment exception and emulate the store.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/8de8580513c1a6e880bad1ba9a69d3efad3d4fa5.1689091022.git.christophe.leroy@csgroup.eu
All but book3s/64 use a static branch key for disabling kuap.
book3s/64 uses an mmu feature.
Refactor all targets to use MMU_FTR_KUAP like book3s/64.
For PPC32 that implies updating mmu features fixups once KUAP
has been initialised.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/6b3d7c977bad73378ea368bc6818e9c94ea95ab0.1689091022.git.christophe.leroy@csgroup.eu
Commit 273df864cf ("ima: Check against blacklisted hashes for files with
modsig") introduced an appraise_flag option for referencing the blacklist
keyring. Any matching binary found on this keyring fails signature
validation. This flag only works with module appended signatures.
An important part of a PKI infrastructure is to have the ability to do
revocation at a later time should a vulnerability be found. Expand the
revocation flag usage to all appraisal functions. The flag is now
enabled by default. Setting the flag with an IMA policy has been
deprecated. Without a revocation capability like this in place, only
authenticity can be maintained. With this change, integrity can now be
achieved with digital signature based IMA appraisal.
Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com>
Reviewed-by: Nayna Jain <nayna@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
When booting on e6500 with an ELF v2 ABI kernel, the secondary threads do
not start correctly:
[ 0.051118] smp: Bringing up secondary CPUs ...
[ 5.072700] Processor 1 is stuck.
This occurs because the startup code is written to use function
descriptors when loading the entry point for the secondary threads. When
building with ELF v2 ABI there are no function descriptors, and the code
loads junk values for the entry point address.
Fix it by using ppc_function_entry() in C, and DOTSYM() in asm, both of
which work correctly for ELF v2 ABI as well as ELF v1 ABI kernels.
Fixes: 8c5fa3b5c4 ("powerpc/64: Make ELFv2 the default for big-endian builds")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230801102650.48705-1-mpe@ellerman.id.au
This function has a __weak definition and an override that is only used on
freescale powerpc chips. The powerpc definition however does not see the
declaration that is in a .c file:
arch/powerpc/kernel/dma-mask.c:7:6: error: no previous prototype for 'arch_dma_set_mask' [-Werror=missing-prototypes]
Move it into the linux/dma-map-ops.h header where the other arch_dma_* functions
are declared.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
With ppc64 -mprofile-kernel and ppc32 -pg, profiling instructions to
call into ftrace are emitted right at function entry. The instruction
sequence used is minimal to reduce overhead. Crucially, a stackframe is
not created for the function being traced. This breaks stack unwinding
since the function being traced does not have a stackframe for itself.
As such, it never shows up in the backtrace:
/sys/kernel/debug/tracing # echo 1 > /proc/sys/kernel/stack_tracer_enabled
/sys/kernel/debug/tracing # cat stack_trace
Depth Size Location (17 entries)
----- ---- --------
0) 4144 32 ftrace_call+0x4/0x44
1) 4112 432 get_page_from_freelist+0x26c/0x1ad0
2) 3680 496 __alloc_pages+0x290/0x1280
3) 3184 336 __folio_alloc+0x34/0x90
4) 2848 176 vma_alloc_folio+0xd8/0x540
5) 2672 272 __handle_mm_fault+0x700/0x1cc0
6) 2400 208 handle_mm_fault+0xf0/0x3f0
7) 2192 80 ___do_page_fault+0x3e4/0xbe0
8) 2112 160 do_page_fault+0x30/0xc0
9) 1952 256 data_access_common_virt+0x210/0x220
10) 1696 400 0xc00000000f16b100
11) 1296 384 load_elf_binary+0x804/0x1b80
12) 912 208 bprm_execve+0x2d8/0x7e0
13) 704 64 do_execveat_common+0x1d0/0x2f0
14) 640 160 sys_execve+0x54/0x70
15) 480 64 system_call_exception+0x138/0x350
16) 416 416 system_call_common+0x160/0x2c4
Fix this by having ftrace create a dummy stackframe for the function
being traced. With this, backtraces now capture the function being
traced:
/sys/kernel/debug/tracing # cat stack_trace
Depth Size Location (17 entries)
----- ---- --------
0) 3888 32 _raw_spin_trylock+0x8/0x70
1) 3856 576 get_page_from_freelist+0x26c/0x1ad0
2) 3280 64 __alloc_pages+0x290/0x1280
3) 3216 336 __folio_alloc+0x34/0x90
4) 2880 176 vma_alloc_folio+0xd8/0x540
5) 2704 416 __handle_mm_fault+0x700/0x1cc0
6) 2288 96 handle_mm_fault+0xf0/0x3f0
7) 2192 48 ___do_page_fault+0x3e4/0xbe0
8) 2144 192 do_page_fault+0x30/0xc0
9) 1952 608 data_access_common_virt+0x210/0x220
10) 1344 16 0xc0000000334bbb50
11) 1328 416 load_elf_binary+0x804/0x1b80
12) 912 64 bprm_execve+0x2d8/0x7e0
13) 848 176 do_execveat_common+0x1d0/0x2f0
14) 672 192 sys_execve+0x54/0x70
15) 480 64 system_call_exception+0x138/0x350
16) 416 416 system_call_common+0x160/0x2c4
This results in two additional stores in the ftrace entry code, but
produces reliable backtraces.
Fixes: 153086644f ("powerpc/ftrace: Add support for -mprofile-kernel ftrace ABI")
Cc: stable@vger.kernel.org
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230621051349.759567-1-naveen@kernel.org
This registers the new fchmodat2 syscall in most places as nuber 452,
with alpha being the exception where it's 562. I found all these sites
by grepping for fspick, which I assume has found me everything.
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
Signed-off-by: Alexey Gladkov <legion@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Message-Id: <a677d521f048e4ca439e7080a5328f21eb8e960e.1689092120.git.legion@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
This partly reverts commit 1e688dd2a3.
That commit aimed at optimising the code around generation of
WARN_ON/BUG_ON but this leads to a lot of dead code erroneously
generated by GCC.
That dead code becomes a problem when we start using objtool validation
because objtool will abort validation with a warning as soon as it
detects unreachable code. This is because unreachable code might
be the indication that objtool doesn't properly decode object text.
text data bss dec hex filename
9551585 3627834 224376 13403795 cc8693 vmlinux.before
9535281 3628358 224376 13388015 cc48ef vmlinux.after
Once this change is reverted, in a standard configuration (pmac32 +
function tracer) the text is reduced by 16k which is around 1.7%
We already had problem with it when starting to use objtool on powerpc
as a replacement for recordmcount, see commit 93e3f45a26 ("powerpc:
Fix __WARN_FLAGS() for use with Objtool")
There is also a problem with at least GCC 12, on ppc64_defconfig +
CONFIG_CC_OPTIMIZE_FOR_SIZE=y + CONFIG_DEBUG_SECTION_MISMATCH=y :
LD .tmp_vmlinux.kallsyms1
powerpc64-linux-ld: net/ipv4/tcp_input.o:(__ex_table+0xc4): undefined reference to `.L2136'
make[2]: *** [scripts/Makefile.vmlinux:36: vmlinux] Error 1
make[1]: *** [/home/chleroy/linux-powerpc/Makefile:1238: vmlinux] Error 2
Taking into account that other problems are encountered with that
'asm goto' in WARN_ON(), including build failures, keeping that
change is not worth it allthough it is primarily a compiler bug.
Revert it for now.
mpe: Retain EMIT_WARN_ENTRY as a synonym for EMIT_BUG_ENTRY to reduce
churn, as there are now nearly as many uses of EMIT_WARN_ENTRY as
EMIT_BUG_ENTRY.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Naveen N Rao <naveen@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230712134552.534955-1-mpe@ellerman.id.au
