linux-stable.git/arch/mips/include/asm, branch v6.7.8 Linux kernel stable tree ptrace: Introduce exception_ip arch hook 2024-02-23T08:51:28+00:00 Jiaxun Yang jiaxun.yang@flygoat.com 2024-02-02T12:30:26+00:00 94691bddb31cd80233068b28ee6394e24a53f753 [ Upstream commit 11ba1728be3edb6928791f4c622f154ebe228ae6 ] On architectures with delay slot, architecture level instruction pointer (or program counter) in pt_regs may differ from where exception was triggered. Introduce exception_ip hook to invoke architecture code and determine actual instruction pointer to the exception. Link: https://lore.kernel.org/lkml/00d1b813-c55f-4365-8d81-d70258e10b16@app.fastmail.com/ Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Stable-dep-of: 8fa507083388 ("mm/memory: Use exception ip to search exception tables") Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 11ba1728be3edb6928791f4c622f154ebe228ae6 ]

On architectures with delay slot, architecture level instruction
pointer (or program counter) in pt_regs may differ from where
exception was triggered.

Introduce exception_ip hook to invoke architecture code and determine
actual instruction pointer to the exception.

Link: https://lore.kernel.org/lkml/00d1b813-c55f-4365-8d81-d70258e10b16@app.fastmail.com/
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Stable-dep-of: 8fa507083388 ("mm/memory: Use exception ip to search exception tables")
Signed-off-by: Sasha Levin <sashal@kernel.org>
MIPS: Add 'memory' clobber to csum_ipv6_magic() inline assembler 2024-02-23T08:51:27+00:00 Guenter Roeck linux@roeck-us.net 2024-02-11T16:08:37+00:00 7d83e05fdfd97e3f5fcda05f423aaf6459b25fe8 [ Upstream commit d55347bfe4e66dce2e1e7501e5492f4af3e315f8 ] After 'lib: checksum: Use aligned accesses for ip_fast_csum and csum_ipv6_magic tests' was applied, the test_csum_ipv6_magic unit test started failing for all mips platforms, both little and bit endian. Oddly enough, adding debug code into test_csum_ipv6_magic() made the problem disappear. The gcc manual says: "The "memory" clobber tells the compiler that the assembly code performs memory reads or writes to items other than those listed in the input and output operands (for example, accessing the memory pointed to by one of the input parameters) " This is definitely the case for csum_ipv6_magic(). Indeed, adding the 'memory' clobber fixes the problem. Cc: Charlie Jenkins <charlie@rivosinc.com> Cc: Palmer Dabbelt <palmer@rivosinc.com> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Guenter Roeck <linux@roeck-us.net> Reviewed-by: Charlie Jenkins <charlie@rivosinc.com> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit d55347bfe4e66dce2e1e7501e5492f4af3e315f8 ]

After 'lib: checksum: Use aligned accesses for ip_fast_csum and
csum_ipv6_magic tests' was applied, the test_csum_ipv6_magic unit test
started failing for all mips platforms, both little and bit endian.
Oddly enough, adding debug code into test_csum_ipv6_magic() made the
problem disappear.

The gcc manual says:

"The "memory" clobber tells the compiler that the assembly code performs
 memory reads or writes to items other than those listed in the input
 and output operands (for example, accessing the memory pointed to by one
 of the input parameters)
"

This is definitely the case for csum_ipv6_magic(). Indeed, adding the
'memory' clobber fixes the problem.

Cc: Charlie Jenkins <charlie@rivosinc.com>
Cc: Palmer Dabbelt <palmer@rivosinc.com>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
work around gcc bugs with 'asm goto' with outputs 2024-02-23T08:51:20+00:00 Linus Torvalds torvalds@linux-foundation.org 2024-02-09T20:39:31+00:00 1bfa8bc86cc788c9c30430f52011c06f11abccd0 commit 4356e9f841f7fbb945521cef3577ba394c65f3fc upstream. We've had issues with gcc and 'asm goto' before, and we created a 'asm_volatile_goto()' macro for that in the past: see commits 3f0116c3238a ("compiler/gcc4: Add quirk for 'asm goto' miscompilation bug") and a9f180345f53 ("compiler/gcc4: Make quirk for asm_volatile_goto() unconditional"). Then, much later, we ended up removing the workaround in commit 43c249ea0b1e ("compiler-gcc.h: remove ancient workaround for gcc PR 58670") because we no longer supported building the kernel with the affected gcc versions, but we left the macro uses around. Now, Sean Christopherson reports a new version of a very similar problem, which is fixed by re-applying that ancient workaround. But the problem in question is limited to only the 'asm goto with outputs' cases, so instead of re-introducing the old workaround as-is, let's rename and limit the workaround to just that much less common case. It looks like there are at least two separate issues that all hit in this area: (a) some versions of gcc don't mark the asm goto as 'volatile' when it has outputs: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98619 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110420 which is easy to work around by just adding the 'volatile' by hand. (b) Internal compiler errors: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110422 which are worked around by adding the extra empty 'asm' as a barrier, as in the original workaround. but the problem Sean sees may be a third thing since it involves bad code generation (not an ICE) even with the manually added 'volatile'. but the same old workaround works for this case, even if this feels a bit like voodoo programming and may only be hiding the issue. Reported-and-tested-by: Sean Christopherson <seanjc@google.com> Link: https://lore.kernel.org/all/20240208220604.140859-1-seanjc@google.com/ Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Uros Bizjak <ubizjak@gmail.com> Cc: Jakub Jelinek <jakub@redhat.com> Cc: Andrew Pinski <quic_apinski@quicinc.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 4356e9f841f7fbb945521cef3577ba394c65f3fc upstream.

We've had issues with gcc and 'asm goto' before, and we created a
'asm_volatile_goto()' macro for that in the past: see commits
3f0116c3238a ("compiler/gcc4: Add quirk for 'asm goto' miscompilation
bug") and a9f180345f53 ("compiler/gcc4: Make quirk for
asm_volatile_goto() unconditional").

Then, much later, we ended up removing the workaround in commit
43c249ea0b1e ("compiler-gcc.h: remove ancient workaround for gcc PR
58670") because we no longer supported building the kernel with the
affected gcc versions, but we left the macro uses around.

Now, Sean Christopherson reports a new version of a very similar
problem, which is fixed by re-applying that ancient workaround.  But the
problem in question is limited to only the 'asm goto with outputs'
cases, so instead of re-introducing the old workaround as-is, let's
rename and limit the workaround to just that much less common case.

It looks like there are at least two separate issues that all hit in
this area:

 (a) some versions of gcc don't mark the asm goto as 'volatile' when it
     has outputs:

        https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98619
        https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110420

     which is easy to work around by just adding the 'volatile' by hand.

 (b) Internal compiler errors:

        https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110422

     which are worked around by adding the extra empty 'asm' as a
     barrier, as in the original workaround.

but the problem Sean sees may be a third thing since it involves bad
code generation (not an ICE) even with the manually added 'volatile'.

but the same old workaround works for this case, even if this feels a
bit like voodoo programming and may only be hiding the issue.

Reported-and-tested-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/all/20240208220604.140859-1-seanjc@google.com/
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Uros Bizjak <ubizjak@gmail.com>
Cc: Jakub Jelinek <jakub@redhat.com>
Cc: Andrew Pinski <quic_apinski@quicinc.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mm: Introduce flush_cache_vmap_early() 2024-02-16T18:14:25+00:00 Alexandre Ghiti alexghiti@rivosinc.com 2023-12-12T21:34:56+00:00 2b89c3f9d3d069924dc1bedd400cd6e93435980c [ Upstream commit 7a92fc8b4d20680e4c20289a670d8fca2d1f2c1b ] The pcpu setup when using the page allocator sets up a new vmalloc mapping very early in the boot process, so early that it cannot use the flush_cache_vmap() function which may depend on structures not yet initialized (for example in riscv, we currently send an IPI to flush other cpus TLB). But on some architectures, we must call flush_cache_vmap(): for example, in riscv, some uarchs can cache invalid TLB entries so we need to flush the new established mapping to avoid taking an exception. So fix this by introducing a new function flush_cache_vmap_early() which is called right after setting the new page table entry and before accessing this new mapping. This new function implements a local flush tlb on riscv and is no-op for other architectures (same as today). Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Dennis Zhou <dennis@kernel.org> Stable-dep-of: d9807d60c145 ("riscv: mm: execute local TLB flush after populating vmemmap") Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 7a92fc8b4d20680e4c20289a670d8fca2d1f2c1b ]

The pcpu setup when using the page allocator sets up a new vmalloc
mapping very early in the boot process, so early that it cannot use the
flush_cache_vmap() function which may depend on structures not yet
initialized (for example in riscv, we currently send an IPI to flush
other cpus TLB).

But on some architectures, we must call flush_cache_vmap(): for example,
in riscv, some uarchs can cache invalid TLB entries so we need to flush
the new established mapping to avoid taking an exception.

So fix this by introducing a new function flush_cache_vmap_early() which
is called right after setting the new page table entry and before
accessing this new mapping. This new function implements a local flush
tlb on riscv and is no-op for other architectures (same as today).

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Stable-dep-of: d9807d60c145 ("riscv: mm: execute local TLB flush after populating vmemmap")
Signed-off-by: Sasha Levin <sashal@kernel.org>
mips: dmi: Fix early remap on MIPS32 2024-01-25T23:45:18+00:00 Serge Semin fancer.lancer@gmail.com 2023-12-02T11:14:18+00:00 12e6ba21af24022ff7917ae1718c0a1f8a44ee2c [ Upstream commit 0d0a3748a2cb38f9da1f08d357688ebd982eb788 ] dmi_early_remap() has been defined as ioremap_cache() which on MIPS32 gets to be converted to the VM-based mapping. DMI early remapping is performed at the setup_arch() stage with no VM available. So calling the dmi_early_remap() for MIPS32 causes the system to crash at the early boot time. Fix that by converting dmi_early_remap() to the uncached remapping which is always available on both 32 and 64-bits MIPS systems. Note this change shall not cause any regressions on the current DMI support implementation because on the early boot-up stage neither MIPS32 nor MIPS64 has the cacheable ioremapping support anyway. Fixes: be8fa1cb444c ("MIPS: Add support for Desktop Management Interface (DMI)") Signed-off-by: Serge Semin <fancer.lancer@gmail.com> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 0d0a3748a2cb38f9da1f08d357688ebd982eb788 ]

dmi_early_remap() has been defined as ioremap_cache() which on MIPS32 gets
to be converted to the VM-based mapping. DMI early remapping is performed
at the setup_arch() stage with no VM available. So calling the
dmi_early_remap() for MIPS32 causes the system to crash at the early boot
time. Fix that by converting dmi_early_remap() to the uncached remapping
which is always available on both 32 and 64-bits MIPS systems.

Note this change shall not cause any regressions on the current DMI
support implementation because on the early boot-up stage neither MIPS32
nor MIPS64 has the cacheable ioremapping support anyway.

Fixes: be8fa1cb444c ("MIPS: Add support for Desktop Management Interface (DMI)")
Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Merge tag 'mm-hotfixes-stable-2023-12-15-07-11' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm 2023-12-15T20:00:54+00:00 Linus Torvalds torvalds@linux-foundation.org 2023-12-15T20:00:54+00:00 a62aa88ba1a386e9b6953083b1ceb2fe027238b9 Pull misc fixes from Andrew Morton: "17 hotfixes. 8 are cc:stable and the other 9 pertain to post-6.6 issues" * tag 'mm-hotfixes-stable-2023-12-15-07-11' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: mm/mglru: reclaim offlined memcgs harder mm/mglru: respect min_ttl_ms with memcgs mm/mglru: try to stop at high watermarks mm/mglru: fix underprotected page cache mm/shmem: fix race in shmem_undo_range w/THP Revert "selftests: error out if kernel header files are not yet built" crash_core: fix the check for whether crashkernel is from high memory x86, kexec: fix the wrong ifdeffery CONFIG_KEXEC sh, kexec: fix the incorrect ifdeffery and dependency of CONFIG_KEXEC mips, kexec: fix the incorrect ifdeffery and dependency of CONFIG_KEXEC m68k, kexec: fix the incorrect ifdeffery and build dependency of CONFIG_KEXEC loongarch, kexec: change dependency of object files mm/damon/core: make damon_start() waits until kdamond_fn() starts selftests/mm: cow: print ksft header before printing anything else mm: fix VMA heap bounds checking riscv: fix VMALLOC_START definition kexec: drop dependency on ARCH_SUPPORTS_KEXEC from CRASH_DUMP 
Pull misc fixes from Andrew Morton:
 "17 hotfixes. 8 are cc:stable and the other 9 pertain to post-6.6
  issues"

* tag 'mm-hotfixes-stable-2023-12-15-07-11' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  mm/mglru: reclaim offlined memcgs harder
  mm/mglru: respect min_ttl_ms with memcgs
  mm/mglru: try to stop at high watermarks
  mm/mglru: fix underprotected page cache
  mm/shmem: fix race in shmem_undo_range w/THP
  Revert "selftests: error out if kernel header files are not yet built"
  crash_core: fix the check for whether crashkernel is from high memory
  x86, kexec: fix the wrong ifdeffery CONFIG_KEXEC
  sh, kexec: fix the incorrect ifdeffery and dependency of CONFIG_KEXEC
  mips, kexec: fix the incorrect ifdeffery and dependency of CONFIG_KEXEC
  m68k, kexec: fix the incorrect ifdeffery and build dependency of CONFIG_KEXEC
  loongarch, kexec: change dependency of object files
  mm/damon/core: make damon_start() waits until kdamond_fn() starts
  selftests/mm: cow: print ksft header before printing anything else
  mm: fix VMA heap bounds checking
  riscv: fix VMALLOC_START definition
  kexec: drop dependency on ARCH_SUPPORTS_KEXEC from CRASH_DUMP
mips, kexec: fix the incorrect ifdeffery and dependency of CONFIG_KEXEC 2023-12-13T01:20:18+00:00 Baoquan He bhe@redhat.com 2023-12-08T07:30:34+00:00 8cd2accb71f5eb8e92d775fc1978d3779875c2e5 The select of KEXEC for CRASH_DUMP in kernel/Kconfig.kexec will be dropped, then compiling errors will be triggered if below config items are set: === CONFIG_CRASH_CORE=y CONFIG_KEXEC_CORE=y CONFIG_CRASH_DUMP=y === -------------------------------------------------------------------- mipsel-linux-ld: kernel/kexec_core.o: in function `kimage_free': kernel/kexec_core.c:(.text+0x2200): undefined reference to `machine_kexec_cleanup' mipsel-linux-ld: kernel/kexec_core.o: in function `__crash_kexec': kernel/kexec_core.c:(.text+0x2480): undefined reference to `machine_crash_shutdown' mipsel-linux-ld: kernel/kexec_core.c:(.text+0x2488): undefined reference to `machine_kexec' mipsel-linux-ld: kernel/kexec_core.o: in function `kernel_kexec': kernel/kexec_core.c:(.text+0x29b8): undefined reference to `machine_shutdown' mipsel-linux-ld: kernel/kexec_core.c:(.text+0x29c0): undefined reference to `machine_kexec' -------------------------------------------------------------------- Here, change the dependency of building kexec_core related object files, and the ifdeffery in mips from CONFIG_KEXEC to CONFIG_KEXEC_CORE. Link: https://lkml.kernel.org/r/20231208073036.7884-4-bhe@redhat.com Signed-off-by: Baoquan He <bhe@redhat.com> Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202311302042.sn8cDPIX-lkp@intel.com/ Cc: Eric DeVolder <eric_devolder@yahoo.com> Cc: Ignat Korchagin <ignat@cloudflare.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> 
The select of KEXEC for CRASH_DUMP in kernel/Kconfig.kexec will be
dropped, then compiling errors will be triggered if below config items are
set:

===
CONFIG_CRASH_CORE=y
CONFIG_KEXEC_CORE=y
CONFIG_CRASH_DUMP=y
===

--------------------------------------------------------------------
mipsel-linux-ld: kernel/kexec_core.o: in function `kimage_free':
kernel/kexec_core.c:(.text+0x2200): undefined reference to `machine_kexec_cleanup'
mipsel-linux-ld: kernel/kexec_core.o: in function `__crash_kexec':
kernel/kexec_core.c:(.text+0x2480): undefined reference to `machine_crash_shutdown'
mipsel-linux-ld: kernel/kexec_core.c:(.text+0x2488): undefined reference to `machine_kexec'
mipsel-linux-ld: kernel/kexec_core.o: in function `kernel_kexec':
kernel/kexec_core.c:(.text+0x29b8): undefined reference to `machine_shutdown'
mipsel-linux-ld: kernel/kexec_core.c:(.text+0x29c0): undefined reference to `machine_kexec'
--------------------------------------------------------------------

Here, change the dependency of building kexec_core related object files,
and the ifdeffery in mips from CONFIG_KEXEC to CONFIG_KEXEC_CORE.

Link: https://lkml.kernel.org/r/20231208073036.7884-4-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202311302042.sn8cDPIX-lkp@intel.com/
Cc: Eric DeVolder <eric_devolder@yahoo.com>
Cc: Ignat Korchagin <ignat@cloudflare.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
MIPS: Loongson64: Handle more memory types passed from firmware 2023-12-05T17:45:24+00:00 Jiaxun Yang jiaxun.yang@flygoat.com 2023-11-07T11:15:20+00:00 c7206e7bd214ebb3ca6fa474a4423662327d9beb There are many types of revsered memory passed from firmware that should be reserved in memblock, and UMA memory passed from firmware that should be added to system memory for system to use. Also for memblock there is no need to align those space into page, which actually cause problems. Handle them properly to prevent memory corruption on some systems. Cc: stable@vger.kernel.org Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> 
There are many types of revsered memory passed from firmware
that should be reserved in memblock, and UMA memory passed
from firmware that should be added to system memory for system
to use.

Also for memblock there is no need to align those space into page,
which actually cause problems.

Handle them properly to prevent memory corruption on some systems.

Cc: stable@vger.kernel.org
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
MIPS: Loongson64: Enable DMA noncoherent support 2023-12-05T17:45:14+00:00 Jiaxun Yang jiaxun.yang@flygoat.com 2023-11-07T11:15:19+00:00 edc0378eee00200a5bedf1bb9f00ad390e0d1bd4 There are some Loongson64 systems come with broken coherent DMA support, firmware will set a bit in boot_param and pass nocoherentio in cmdline. However nonconherent support was missed out when spin off Loongson-2EF form Loongson64, and that boot_param change never made itself into upstream. Support DMA noncoherent properly to get those systems working. Cc: stable@vger.kernel.org Fixes: 71e2f4dd5a65 ("MIPS: Fork loongson2ef from loongson64") Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> 
There are some Loongson64 systems come with broken coherent DMA
support, firmware will set a bit in boot_param and pass nocoherentio
in cmdline.

However nonconherent support was missed out when spin off Loongson-2EF
form Loongson64, and that boot_param change never made itself into
upstream.

Support DMA noncoherent properly to get those systems working.

Cc: stable@vger.kernel.org
Fixes: 71e2f4dd5a65 ("MIPS: Fork loongson2ef from loongson64")
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Merge tag 'probes-fixes-v6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace 2023-11-11T00:35:04+00:00 Linus Torvalds torvalds@linux-foundation.org 2023-11-11T00:35:04+00:00 3ca112b71f35dd5d99fc4571a56b5fc6f0c15814 Pull probes fixes from Masami Hiramatsu: - Documentation update: Add a note about argument and return value fetching is the best effort because it depends on the type. - objpool: Fix to make internal global variables static in test_objpool.c. - kprobes: Unify kprobes_exceptions_nofify() prototypes. There are the same prototypes in asm/kprobes.h for some architectures, but some of them are missing the prototype and it causes a warning. So move the prototype into linux/kprobes.h. - tracing: Fix to check the tracepoint event and return event at parsing stage. The tracepoint event doesn't support %return but if $retval exists, it will be converted to %return silently. This finds that case and rejects it. - tracing: Fix the order of the descriptions about the parameters of __kprobe_event_gen_cmd_start() to be consistent with the argument list of the function. * tag 'probes-fixes-v6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: tracing/kprobes: Fix the order of argument descriptions tracing: fprobe-event: Fix to check tracepoint event and return kprobes: unify kprobes_exceptions_nofify() prototypes lib: test_objpool: make global variables static Documentation: tracing: Add a note about argument and retval access 
Pull probes fixes from Masami Hiramatsu:

 - Documentation update: Add a note about argument and return value
   fetching is the best effort because it depends on the type.

 - objpool: Fix to make internal global variables static in
   test_objpool.c.

 - kprobes: Unify kprobes_exceptions_nofify() prototypes. There are the
   same prototypes in asm/kprobes.h for some architectures, but some of
   them are missing the prototype and it causes a warning. So move the
   prototype into linux/kprobes.h.

 - tracing: Fix to check the tracepoint event and return event at
   parsing stage. The tracepoint event doesn't support %return but if
   $retval exists, it will be converted to %return silently. This finds
   that case and rejects it.

 - tracing: Fix the order of the descriptions about the parameters of
   __kprobe_event_gen_cmd_start() to be consistent with the argument
   list of the function.

* tag 'probes-fixes-v6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing/kprobes: Fix the order of argument descriptions
  tracing: fprobe-event: Fix to check tracepoint event and return
  kprobes: unify kprobes_exceptions_nofify() prototypes
  lib: test_objpool: make global variables static
  Documentation: tracing: Add a note about argument and retval access