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
3f0116c323 ("compiler/gcc4: Add quirk for 'asm goto' miscompilation
bug") and a9f180345f ("compiler/gcc4: Make quirk for
asm_volatile_goto() unconditional").
Then, much later, we ended up removing the workaround in commit
43c249ea0b ("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=98619https://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>
Add DEFINE_FLEX() macro for on-stack allocations of structs with
flexible array member.
Expose __struct_size() macro outside of fortify-string.h, as it could be
used to read size of structs allocated by DEFINE_FLEX().
Move __member_size() alongside it.
-Kees
Using underlying array for on-stack storage lets us to declare
known-at-compile-time structures without kzalloc().
Actual usage for ice driver is in following patches of the series.
Missing __has_builtin() workaround is moved up to serve also assembly
compilation with m68k-linux-gcc, see [1].
Error was (note the .S file extension):
In file included from ../include/linux/linkage.h:5,
from ../arch/m68k/fpsp040/skeleton.S:40:
../include/linux/compiler_types.h:331:5: warning: "__has_builtin" is not defined, evaluates to 0 [-Wundef]
331 | #if __has_builtin(__builtin_dynamic_object_size)
| ^~~~~~~~~~~~~
../include/linux/compiler_types.h:331:18: error: missing binary operator before token "("
331 | #if __has_builtin(__builtin_dynamic_object_size)
| ^
[1] https://lore.kernel.org/netdev/202308112122.OuF0YZqL-lkp@intel.com/
Co-developed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Link: https://lore.kernel.org/r/20230912115937.1645707-2-przemyslaw.kitszel@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
[1]: "On X86-64 and AArch64 targets, this attribute changes the calling
convention of a function. The preserve_most calling convention attempts
to make the code in the caller as unintrusive as possible. This
convention behaves identically to the C calling convention on how
arguments and return values are passed, but it uses a different set of
caller/callee-saved registers. This alleviates the burden of saving and
recovering a large register set before and after the call in the caller.
If the arguments are passed in callee-saved registers, then they will be
preserved by the callee across the call. This doesn't apply for values
returned in callee-saved registers.
* On X86-64 the callee preserves all general purpose registers, except
for R11. R11 can be used as a scratch register. Floating-point
registers (XMMs/YMMs) are not preserved and need to be saved by the
caller.
* On AArch64 the callee preserve all general purpose registers, except
x0-X8 and X16-X18."
[1] https://clang.llvm.org/docs/AttributeReference.html#preserve-most
Introduce the attribute to compiler_types.h as __preserve_most.
Use of this attribute results in better code generation for calls to
very rarely called functions, such as error-reporting functions, or
rarely executed slow paths.
Beware that the attribute conflicts with instrumentation calls inserted
on function entry which do not use __preserve_most themselves. Notably,
function tracing which assumes the normal C calling convention for the
given architecture. Where the attribute is supported, __preserve_most
will imply notrace. It is recommended to restrict use of the attribute
to functions that should or already disable tracing.
Note: The additional preprocessor check against architecture should not
be necessary if __has_attribute() only returns true where supported;
also see https://github.com/ClangBuiltLinux/linux/issues/1908. But until
__has_attribute() does the right thing, we also guard by known-supported
architectures to avoid build warnings on other architectures.
The attribute may be supported by a future GCC version (see
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110899).
Signed-off-by: Marco Elver <elver@google.com>
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: "Steven Rostedt (Google)" <rostedt@goodmis.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20230811151847.1594958-1-elver@google.com
Signed-off-by: Kees Cook <keescook@chromium.org>
include/linux/compiler-intel.h had no update in the past 3 years.
We often forget about the third C compiler to build the kernel.
For example, commit a0a12c3ed0 ("asm goto: eradicate CC_HAS_ASM_GOTO")
only mentioned GCC and Clang.
init/Kconfig defines CC_IS_GCC and CC_IS_CLANG but not CC_IS_ICC,
and nobody has reported any issue.
I guess the Intel Compiler support is broken, and nobody is caring
about it.
Harald Arnesen pointed out ICC (classic Intel C/C++ compiler) is
deprecated:
$ icc -v
icc: remark #10441: The Intel(R) C++ Compiler Classic (ICC) is
deprecated and will be removed from product release in the second half
of 2023. The Intel(R) oneAPI DPC++/C++ Compiler (ICX) is the recommended
compiler moving forward. Please transition to use this compiler. Use
'-diag-disable=10441' to disable this message.
icc version 2021.7.0 (gcc version 12.1.0 compatibility)
Arnd Bergmann provided a link to the article, "Intel C/C++ compilers
complete adoption of LLVM".
lib/zstd/common/compiler.h and lib/zstd/compress/zstd_fast.c were kept
untouched for better sync with https://github.com/facebook/zstd
Link: https://www.intel.com/content/www/us/en/developer/articles/technical/adoption-of-llvm-complete-icx.html
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- Support for arm64 SME 2 and 2.1. SME2 introduces a new 512-bit
architectural register (ZT0, for the look-up table feature) that Linux
needs to save/restore.
- Include TPIDR2 in the signal context and add the corresponding
kselftests.
- Perf updates: Arm SPEv1.2 support, HiSilicon uncore PMU updates, ACPI
support to the Marvell DDR and TAD PMU drivers, reset DTM_PMU_CONFIG
(ARM CMN) at probe time.
- Support for DYNAMIC_FTRACE_WITH_CALL_OPS on arm64.
- Permit EFI boot with MMU and caches on. Instead of cleaning the entire
loaded kernel image to the PoC and disabling the MMU and caches before
branching to the kernel bare metal entry point, leave the MMU and
caches enabled and rely on EFI's cacheable 1:1 mapping of all of
system RAM to populate the initial page tables.
- Expose the AArch32 (compat) ELF_HWCAP features to user in an arm64
kernel (the arm32 kernel only defines the values).
- Harden the arm64 shadow call stack pointer handling: stash the shadow
stack pointer in the task struct on interrupt, load it directly from
this structure.
- Signal handling cleanups to remove redundant validation of size
information and avoid reading the same data from userspace twice.
- Refactor the hwcap macros to make use of the automatically generated
ID registers. It should make new hwcaps writing less error prone.
- Further arm64 sysreg conversion and some fixes.
- arm64 kselftest fixes and improvements.
- Pointer authentication cleanups: don't sign leaf functions, unify
asm-arch manipulation.
- Pseudo-NMI code generation optimisations.
- Minor fixes for SME and TPIDR2 handling.
- Miscellaneous updates: ARCH_FORCE_MAX_ORDER is now selectable, replace
strtobool() to kstrtobool() in the cpufeature.c code, apply dynamic
shadow call stack in two passes, intercept pfn changes in set_pte_at()
without the required break-before-make sequence, attempt to dump all
instructions on unhandled kernel faults.
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 updates from Catalin Marinas:
- Support for arm64 SME 2 and 2.1. SME2 introduces a new 512-bit
architectural register (ZT0, for the look-up table feature) that
Linux needs to save/restore
- Include TPIDR2 in the signal context and add the corresponding
kselftests
- Perf updates: Arm SPEv1.2 support, HiSilicon uncore PMU updates, ACPI
support to the Marvell DDR and TAD PMU drivers, reset DTM_PMU_CONFIG
(ARM CMN) at probe time
- Support for DYNAMIC_FTRACE_WITH_CALL_OPS on arm64
- Permit EFI boot with MMU and caches on. Instead of cleaning the
entire loaded kernel image to the PoC and disabling the MMU and
caches before branching to the kernel bare metal entry point, leave
the MMU and caches enabled and rely on EFI's cacheable 1:1 mapping of
all of system RAM to populate the initial page tables
- Expose the AArch32 (compat) ELF_HWCAP features to user in an arm64
kernel (the arm32 kernel only defines the values)
- Harden the arm64 shadow call stack pointer handling: stash the shadow
stack pointer in the task struct on interrupt, load it directly from
this structure
- Signal handling cleanups to remove redundant validation of size
information and avoid reading the same data from userspace twice
- Refactor the hwcap macros to make use of the automatically generated
ID registers. It should make new hwcaps writing less error prone
- Further arm64 sysreg conversion and some fixes
- arm64 kselftest fixes and improvements
- Pointer authentication cleanups: don't sign leaf functions, unify
asm-arch manipulation
- Pseudo-NMI code generation optimisations
- Minor fixes for SME and TPIDR2 handling
- Miscellaneous updates: ARCH_FORCE_MAX_ORDER is now selectable,
replace strtobool() to kstrtobool() in the cpufeature.c code, apply
dynamic shadow call stack in two passes, intercept pfn changes in
set_pte_at() without the required break-before-make sequence, attempt
to dump all instructions on unhandled kernel faults
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (130 commits)
arm64: fix .idmap.text assertion for large kernels
kselftest/arm64: Don't require FA64 for streaming SVE+ZA tests
kselftest/arm64: Copy whole EXTRA context
arm64: kprobes: Drop ID map text from kprobes blacklist
perf: arm_spe: Print the version of SPE detected
perf: arm_spe: Add support for SPEv1.2 inverted event filtering
perf: Add perf_event_attr::config3
arm64/sme: Fix __finalise_el2 SMEver check
drivers/perf: fsl_imx8_ddr_perf: Remove set-but-not-used variable
arm64/signal: Only read new data when parsing the ZT context
arm64/signal: Only read new data when parsing the ZA context
arm64/signal: Only read new data when parsing the SVE context
arm64/signal: Avoid rereading context frame sizes
arm64/signal: Make interface for restore_fpsimd_context() consistent
arm64/signal: Remove redundant size validation from parse_user_sigframe()
arm64/signal: Don't redundantly verify FPSIMD magic
arm64/cpufeature: Use helper macros to specify hwcaps
arm64/cpufeature: Always use symbolic name for feature value in hwcaps
arm64/sysreg: Initial unsigned annotations for ID registers
arm64/sysreg: Initial annotation of signed ID registers
...
Contemporary versions of GCC (e.g. GCC 12.2.0) drop the alignment
specified by '-falign-functions=N' for functions marked with the
__cold__ attribute, and potentially for callees of __cold__ functions as
these may be implicitly marked as __cold__ by the compiler. LLVM appears
to respect '-falign-functions=N' in such cases.
This has been reported to GCC in bug 88345:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88345
... which also covers alignment being dropped when '-Os' is used, which
will be addressed in a separate patch.
Currently, use of '-falign-functions=N' is limited to
CONFIG_FUNCTION_ALIGNMENT, which is largely used for performance and/or
analysis reasons (e.g. with CONFIG_DEBUG_FORCE_FUNCTION_ALIGN_64B), but
isn't necessary for correct functionality. However, this dropped
alignment isn't great for the performance and/or analysis cases.
Subsequent patches will use CONFIG_FUNCTION_ALIGNMENT as part of arm64's
ftrace implementation, which will require all instrumented functions to
be aligned to at least 8-bytes.
This patch works around the dropped alignment by avoiding the use of the
__cold__ attribute when CONFIG_FUNCTION_ALIGNMENT is non-zero, and by
specifically aligning abort(), which GCC implicitly marks as __cold__.
As the __cold macro is now dependent upon config options (which is
against the policy described at the top of compiler_attributes.h), it is
moved into compiler_types.h.
I've tested this by building and booting a kernel configured with
defconfig + CONFIG_EXPERT=y + CONFIG_DEBUG_FORCE_FUNCTION_ALIGN_64B=y,
and looking for misaligned text symbols in /proc/kallsyms:
* arm64:
Before:
# uname -rm
6.2.0-rc3 aarch64
# grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | wc -l
5009
After:
# uname -rm
6.2.0-rc3-00001-g2a2bedf8bfa9 aarch64
# grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | wc -l
919
* x86_64:
Before:
# uname -rm
6.2.0-rc3 x86_64
# grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | wc -l
11537
After:
# uname -rm
6.2.0-rc3-00001-g2a2bedf8bfa9 x86_64
# grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | wc -l
2805
There's clearly a substantial reduction in the number of misaligned
symbols. From manual inspection, the remaining unaligned text labels are
a combination of ACPICA functions (due to the use of '-Os'), static call
trampolines, and non-function labels in assembly, which will be dealt
with in subsequent patches.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Florent Revest <revest@chromium.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Deacon <will@kernel.org>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20230123134603.1064407-3-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Idle code is very like entry code in that RCU isn't available. As
such, add a little validation.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20230112195540.373461409@infradead.org
Currently, without rcu attribute info in BTF, the verifier treats
rcu tagged pointer as a normal pointer. This might be a problem
for sleepable program where rcu_read_lock()/unlock() is not available.
For example, for a sleepable fentry program, if rcu protected memory
access is interleaved with a sleepable helper/kfunc, it is possible
the memory access after the sleepable helper/kfunc might be invalid
since the object might have been freed then. To prevent such cases,
introducing rcu tagging for memory accesses in verifier can help
to reject such programs.
To enable rcu tagging in BTF, during kernel compilation,
define __rcu as attribute btf_type_tag("rcu") so __rcu information can
be preserved in dwarf and btf, and later can be used for bpf prog verification.
Acked-by: KP Singh <kpsingh@kernel.org>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20221124053206.2373141-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
linux-next for a couple of months without, to my knowledge, any negative
reports (or any positive ones, come to that).
- Also the Maple Tree from Liam R. Howlett. An overlapping range-based
tree for vmas. It it apparently slight more efficient in its own right,
but is mainly targeted at enabling work to reduce mmap_lock contention.
Liam has identified a number of other tree users in the kernel which
could be beneficially onverted to mapletrees.
Yu Zhao has identified a hard-to-hit but "easy to fix" lockdep splat
(https://lkml.kernel.org/r/CAOUHufZabH85CeUN-MEMgL8gJGzJEWUrkiM58JkTbBhh-jew0Q@mail.gmail.com).
This has yet to be addressed due to Liam's unfortunately timed
vacation. He is now back and we'll get this fixed up.
- Dmitry Vyukov introduces KMSAN: the Kernel Memory Sanitizer. It uses
clang-generated instrumentation to detect used-unintialized bugs down to
the single bit level.
KMSAN keeps finding bugs. New ones, as well as the legacy ones.
- Yang Shi adds a userspace mechanism (madvise) to induce a collapse of
memory into THPs.
- Zach O'Keefe has expanded Yang Shi's madvise(MADV_COLLAPSE) to support
file/shmem-backed pages.
- userfaultfd updates from Axel Rasmussen
- zsmalloc cleanups from Alexey Romanov
- cleanups from Miaohe Lin: vmscan, hugetlb_cgroup, hugetlb and memory-failure
- Huang Ying adds enhancements to NUMA balancing memory tiering mode's
page promotion, with a new way of detecting hot pages.
- memcg updates from Shakeel Butt: charging optimizations and reduced
memory consumption.
- memcg cleanups from Kairui Song.
- memcg fixes and cleanups from Johannes Weiner.
- Vishal Moola provides more folio conversions
- Zhang Yi removed ll_rw_block() :(
- migration enhancements from Peter Xu
- migration error-path bugfixes from Huang Ying
- Aneesh Kumar added ability for a device driver to alter the memory
tiering promotion paths. For optimizations by PMEM drivers, DRM
drivers, etc.
- vma merging improvements from Jakub Matěn.
- NUMA hinting cleanups from David Hildenbrand.
- xu xin added aditional userspace visibility into KSM merging activity.
- THP & KSM code consolidation from Qi Zheng.
- more folio work from Matthew Wilcox.
- KASAN updates from Andrey Konovalov.
- DAMON cleanups from Kaixu Xia.
- DAMON work from SeongJae Park: fixes, cleanups.
- hugetlb sysfs cleanups from Muchun Song.
- Mike Kravetz fixes locking issues in hugetlbfs and in hugetlb core.
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Merge tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- Yu Zhao's Multi-Gen LRU patches are here. They've been under test in
linux-next for a couple of months without, to my knowledge, any
negative reports (or any positive ones, come to that).
- Also the Maple Tree from Liam Howlett. An overlapping range-based
tree for vmas. It it apparently slightly more efficient in its own
right, but is mainly targeted at enabling work to reduce mmap_lock
contention.
Liam has identified a number of other tree users in the kernel which
could be beneficially onverted to mapletrees.
Yu Zhao has identified a hard-to-hit but "easy to fix" lockdep splat
at [1]. This has yet to be addressed due to Liam's unfortunately
timed vacation. He is now back and we'll get this fixed up.
- Dmitry Vyukov introduces KMSAN: the Kernel Memory Sanitizer. It uses
clang-generated instrumentation to detect used-unintialized bugs down
to the single bit level.
KMSAN keeps finding bugs. New ones, as well as the legacy ones.
- Yang Shi adds a userspace mechanism (madvise) to induce a collapse of
memory into THPs.
- Zach O'Keefe has expanded Yang Shi's madvise(MADV_COLLAPSE) to
support file/shmem-backed pages.
- userfaultfd updates from Axel Rasmussen
- zsmalloc cleanups from Alexey Romanov
- cleanups from Miaohe Lin: vmscan, hugetlb_cgroup, hugetlb and
memory-failure
- Huang Ying adds enhancements to NUMA balancing memory tiering mode's
page promotion, with a new way of detecting hot pages.
- memcg updates from Shakeel Butt: charging optimizations and reduced
memory consumption.
- memcg cleanups from Kairui Song.
- memcg fixes and cleanups from Johannes Weiner.
- Vishal Moola provides more folio conversions
- Zhang Yi removed ll_rw_block() :(
- migration enhancements from Peter Xu
- migration error-path bugfixes from Huang Ying
- Aneesh Kumar added ability for a device driver to alter the memory
tiering promotion paths. For optimizations by PMEM drivers, DRM
drivers, etc.
- vma merging improvements from Jakub Matěn.
- NUMA hinting cleanups from David Hildenbrand.
- xu xin added aditional userspace visibility into KSM merging
activity.
- THP & KSM code consolidation from Qi Zheng.
- more folio work from Matthew Wilcox.
- KASAN updates from Andrey Konovalov.
- DAMON cleanups from Kaixu Xia.
- DAMON work from SeongJae Park: fixes, cleanups.
- hugetlb sysfs cleanups from Muchun Song.
- Mike Kravetz fixes locking issues in hugetlbfs and in hugetlb core.
Link: https://lkml.kernel.org/r/CAOUHufZabH85CeUN-MEMgL8gJGzJEWUrkiM58JkTbBhh-jew0Q@mail.gmail.com [1]
* tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (555 commits)
hugetlb: allocate vma lock for all sharable vmas
hugetlb: take hugetlb vma_lock when clearing vma_lock->vma pointer
hugetlb: fix vma lock handling during split vma and range unmapping
mglru: mm/vmscan.c: fix imprecise comments
mm/mglru: don't sync disk for each aging cycle
mm: memcontrol: drop dead CONFIG_MEMCG_SWAP config symbol
mm: memcontrol: use do_memsw_account() in a few more places
mm: memcontrol: deprecate swapaccounting=0 mode
mm: memcontrol: don't allocate cgroup swap arrays when memcg is disabled
mm/secretmem: remove reduntant return value
mm/hugetlb: add available_huge_pages() func
mm: remove unused inline functions from include/linux/mm_inline.h
selftests/vm: add selftest for MADV_COLLAPSE of uffd-minor memory
selftests/vm: add file/shmem MADV_COLLAPSE selftest for cleared pmd
selftests/vm: add thp collapse shmem testing
selftests/vm: add thp collapse file and tmpfs testing
selftests/vm: modularize thp collapse memory operations
selftests/vm: dedup THP helpers
mm/khugepaged: add tracepoint to hpage_collapse_scan_file()
mm/madvise: add file and shmem support to MADV_COLLAPSE
...
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Merge tag 'slab-for-6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab
Pull slab fixes from Vlastimil Babka:
- The "common kmalloc v4" series [1] by Hyeonggon Yoo.
While the plan after LPC is to try again if it's possible to get rid
of SLOB and SLAB (and if any critical aspect of those is not possible
to achieve with SLUB today, modify it accordingly), it will take a
while even in case there are no objections.
Meanwhile this is a nice cleanup and some parts (e.g. to the
tracepoints) will be useful even if we end up with a single slab
implementation in the future:
- Improves the mm/slab_common.c wrappers to allow deleting
duplicated code between SLAB and SLUB.
- Large kmalloc() allocations in SLAB are passed to page allocator
like in SLUB, reducing number of kmalloc caches.
- Removes the {kmem_cache_alloc,kmalloc}_node variants of
tracepoints, node id parameter added to non-_node variants.
- Addition of kmalloc_size_roundup()
The first two patches from a series by Kees Cook [2] that introduce
kmalloc_size_roundup(). This will allow merging of per-subsystem
patches using the new function and ultimately stop (ab)using ksize()
in a way that causes ongoing trouble for debugging functionality and
static checkers.
- Wasted kmalloc() memory tracking in debugfs alloc_traces
A patch from Feng Tang that enhances the existing debugfs
alloc_traces file for kmalloc caches with information about how much
space is wasted by allocations that needs less space than the
particular kmalloc cache provides.
- My series [3] to fix validation races for caches with enabled
debugging:
- By decoupling the debug cache operation more from non-debug
fastpaths, extra locking simplifications were possible and thus
done afterwards.
- Additional cleanup of PREEMPT_RT specific code on top, by Thomas
Gleixner.
- A late fix for slab page leaks caused by the series, by Feng
Tang.
- Smaller fixes and cleanups:
- Unneeded variable removals, by ye xingchen
- A cleanup removing a BUG_ON() in create_unique_id(), by Chao Yu
Link: https://lore.kernel.org/all/20220817101826.236819-1-42.hyeyoo@gmail.com/ [1]
Link: https://lore.kernel.org/all/20220923202822.2667581-1-keescook@chromium.org/ [2]
Link: https://lore.kernel.org/all/20220823170400.26546-1-vbabka@suse.cz/ [3]
* tag 'slab-for-6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab: (30 commits)
mm/slub: fix a slab missed to be freed problem
slab: Introduce kmalloc_size_roundup()
slab: Remove __malloc attribute from realloc functions
mm/slub: clean up create_unique_id()
mm/slub: enable debugging memory wasting of kmalloc
slub: Make PREEMPT_RT support less convoluted
mm/slub: simplify __cmpxchg_double_slab() and slab_[un]lock()
mm/slub: convert object_map_lock to non-raw spinlock
mm/slub: remove slab_lock() usage for debug operations
mm/slub: restrict sysfs validation to debug caches and make it safe
mm/sl[au]b: check if large object is valid in __ksize()
mm/slab_common: move declaration of __ksize() to mm/slab.h
mm/slab_common: drop kmem_alloc & avoid dereferencing fields when not using
mm/slab_common: unify NUMA and UMA version of tracepoints
mm/sl[au]b: cleanup kmem_cache_alloc[_node]_trace()
mm/sl[au]b: generalize kmalloc subsystem
mm/slub: move free_debug_processing() further
mm/sl[au]b: introduce common alloc/free functions without tracepoint
mm/slab: kmalloc: pass requests larger than order-1 page to page allocator
mm/slab_common: cleanup kmalloc_large()
...
This replaces the prior support for Clang's standard Control Flow
Integrity (CFI) instrumentation, which has required a lot of special
conditions (e.g. LTO) and work-arounds. The current implementation
("Kernel CFI") is specific to C, directly designed for the Linux kernel,
and takes advantage of architectural features like x86's IBT. This
series retains arm64 support and adds x86 support. Additional "generic"
architectural support is expected soon:
https://github.com/samitolvanen/llvm-project/commits/kcfi_generic
- treewide: Remove old CFI support details
- arm64: Replace Clang CFI support with Clang KCFI support
- x86: Introduce Clang KCFI support
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Merge tag 'kcfi-v6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull kcfi updates from Kees Cook:
"This replaces the prior support for Clang's standard Control Flow
Integrity (CFI) instrumentation, which has required a lot of special
conditions (e.g. LTO) and work-arounds.
The new implementation ("Kernel CFI") is specific to C, directly
designed for the Linux kernel, and takes advantage of architectural
features like x86's IBT. This series retains arm64 support and adds
x86 support.
GCC support is expected in the future[1], and additional "generic"
architectural support is expected soon[2].
Summary:
- treewide: Remove old CFI support details
- arm64: Replace Clang CFI support with Clang KCFI support
- x86: Introduce Clang KCFI support"
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107048 [1]
Link: https://github.com/samitolvanen/llvm-project/commits/kcfi_generic [2]
* tag 'kcfi-v6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (22 commits)
x86: Add support for CONFIG_CFI_CLANG
x86/purgatory: Disable CFI
x86: Add types to indirectly called assembly functions
x86/tools/relocs: Ignore __kcfi_typeid_ relocations
kallsyms: Drop CONFIG_CFI_CLANG workarounds
objtool: Disable CFI warnings
objtool: Preserve special st_shndx indexes in elf_update_symbol
treewide: Drop __cficanonical
treewide: Drop WARN_ON_FUNCTION_MISMATCH
treewide: Drop function_nocfi
init: Drop __nocfi from __init
arm64: Drop unneeded __nocfi attributes
arm64: Add CFI error handling
arm64: Add types to indirect called assembly functions
psci: Fix the function type for psci_initcall_t
lkdtm: Emit an indirect call for CFI tests
cfi: Add type helper macros
cfi: Switch to -fsanitize=kcfi
cfi: Drop __CFI_ADDRESSABLE
cfi: Remove CONFIG_CFI_CLANG_SHADOW
...
The __malloc attribute should not be applied to "realloc" functions, as
the returned pointer may alias the storage of the prior pointer. Instead
of splitting __malloc from __alloc_size, which would be a huge amount of
churn, just create __realloc_size for the few cases where it is needed.
Thanks to Geert Uytterhoeven <geert@linux-m68k.org> for reporting build
failures with gcc-8 in earlier version which tried to remove the #ifdef.
While the "alloc_size" attribute is available on all GCC versions, I
forgot that it gets disabled explicitly by the kernel in GCC < 9.1 due
to misbehaviors. Add a note to the compiler_attributes.h entry for it.
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Marco Elver <elver@google.com>
Cc: linux-mm@kvack.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Having most of the new files in place, we now enable Rust support
in the build system, including `Kconfig` entries related to Rust,
the Rust configuration printer and a few other bits.
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
Co-developed-by: Finn Behrens <me@kloenk.de>
Signed-off-by: Finn Behrens <me@kloenk.de>
Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com>
Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com>
Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Co-developed-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com>
Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com>
Co-developed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Gary Guo <gary@garyguo.net>
Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de>
Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de>
Co-developed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Co-developed-by: Douglas Su <d0u9.su@outlook.com>
Signed-off-by: Douglas Su <d0u9.su@outlook.com>
Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl>
Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl>
Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org>
Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org>
Co-developed-by: Daniel Xu <dxu@dxuuu.xyz>
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
CONFIG_CFI_CLANG doesn't use a jump table anymore and therefore,
won't change function references to point elsewhere. Remove the
__cficanonical attribute and all uses of it.
Note that the Clang definition of the attribute was removed earlier,
just clean up the no-op definition and users.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Kees Cook <keescook@chromium.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220908215504.3686827-16-samitolvanen@google.com
The kernel tends to try to avoid conditional locking semantics because
it makes it harder to think about and statically check locking rules,
but we do have a few fundamental locking primitives that take locks
conditionally - most obviously the 'trylock' functions.
That has always been a problem for 'sparse' checking for locking
imbalance, and we've had a special '__cond_lock()' macro that we've used
to let sparse know how the locking works:
# define __cond_lock(x,c) ((c) ? ({ __acquire(x); 1; }) : 0)
so that you can then use this to tell sparse that (for example) the
spinlock trylock macro ends up acquiring the lock when it succeeds, but
not when it fails:
#define raw_spin_trylock(lock) __cond_lock(lock, _raw_spin_trylock(lock))
and then sparse can follow along the locking rules when you have code like
if (!spin_trylock(&dentry->d_lock))
return LRU_SKIP;
.. sparse sees that the lock is held here..
spin_unlock(&dentry->d_lock);
and sparse ends up happy about the lock contexts.
However, this '__cond_lock()' use does result in very ugly header files,
and requires you to basically wrap the real function with that macro
that uses '__cond_lock'. Which has made PeterZ NAK things that try to
fix sparse warnings over the years [1].
To solve this, there is now a very experimental patch to sparse that
basically does the exact same thing as '__cond_lock()' did, but using a
function attribute instead. That seems to make PeterZ happy [2].
Note that this does not replace existing use of '__cond_lock()', but
only exposes the new proposed attribute and uses it for the previously
unannotated 'refcount_dec_and_lock()' family of functions.
For existing sparse installations, this will make no difference (a
negative output context was ignored), but if you have the experimental
sparse patch it will make sparse now understand code that uses those
functions, the same way '__cond_lock()' makes sparse understand the very
similar 'atomic_dec_and_lock()' uses that have the old '__cond_lock()'
annotations.
Note that in some cases this will silence existing context imbalance
warnings. But in other cases it may end up exposing new sparse warnings
for code that sparse just didn't see the locking for at all before.
This is a trial, in other words. I'd expect that if it ends up being
successful, and new sparse releases end up having this new attribute,
we'll migrate the old-style '__cond_lock()' users to use the new-style
'__cond_acquires' function attribute.
The actual experimental sparse patch was posted in [3].
Link: https://lore.kernel.org/all/20130930134434.GC12926@twins.programming.kicks-ass.net/ [1]
Link: https://lore.kernel.org/all/Yr60tWxN4P568x3W@worktop.programming.kicks-ass.net/ [2]
Link: https://lore.kernel.org/all/CAHk-=wjZfO9hGqJ2_hGQG3U_XzSh9_XaXze=HgPdvJbgrvASfA@mail.gmail.com/ [3]
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Alexander Aring <aahringo@redhat.com>
Cc: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In preparation for Clang supporting randstruct, reorganize the Kconfigs,
move the attribute macros, and generalize the feature to be named
CONFIG_RANDSTRUCT for on/off, CONFIG_RANDSTRUCT_FULL for the full
randomization mode, and CONFIG_RANDSTRUCT_PERFORMANCE for the cache-line
sized mode.
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220503205503.3054173-4-keescook@chromium.org
Merge more updates from Andrew Morton:
"Various misc subsystems, before getting into the post-linux-next
material.
41 patches.
Subsystems affected by this patch series: procfs, misc, core-kernel,
lib, checkpatch, init, pipe, minix, fat, cgroups, kexec, kdump,
taskstats, panic, kcov, resource, and ubsan"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (41 commits)
Revert "ubsan, kcsan: Don't combine sanitizer with kcov on clang"
kernel/resource: fix kfree() of bootmem memory again
kcov: properly handle subsequent mmap calls
kcov: split ioctl handling into locked and unlocked parts
panic: move panic_print before kmsg dumpers
panic: add option to dump all CPUs backtraces in panic_print
docs: sysctl/kernel: add missing bit to panic_print
taskstats: remove unneeded dead assignment
kasan: no need to unset panic_on_warn in end_report()
ubsan: no need to unset panic_on_warn in ubsan_epilogue()
panic: unset panic_on_warn inside panic()
docs: kdump: add scp example to write out the dump file
docs: kdump: update description about sysfs file system support
arm64: mm: use IS_ENABLED(CONFIG_KEXEC_CORE) instead of #ifdef
x86/setup: use IS_ENABLED(CONFIG_KEXEC_CORE) instead of #ifdef
riscv: mm: init: use IS_ENABLED(CONFIG_KEXEC_CORE) instead of #ifdef
kexec: make crashk_res, crashk_low_res and crash_notes symbols always visible
cgroup: use irqsave in cgroup_rstat_flush_locked().
fat: use pointer to simple type in put_user()
minix: fix bug when opening a file with O_DIRECT
...
(1) compiler_types.h is unconditionally included via an -include flag
(see scripts/Makefile.lib), and it defines __compiler_offsetof
unconditionally. So testing for definedness of __compiler_offsetof is
mostly pointless.
(2) Every relevant compiler provides __builtin_offsetof (even sparse
has had that for 14 years), and if for whatever reason one would end
up picking up the poor man's fallback definition (C file compiler with
completely custom CFLAGS?), newer clang versions won't treat the
result as an Integer Constant Expression, so if used in place where
such is required (static initializer or static_assert), one would get
errors like
t.c:11:16: error: static_assert expression is not an integral constant expression
t.c:11:16: note: cast that performs the conversions of a reinterpret_cast is not allowed in a constant expression
t.c:4:33: note: expanded from macro 'offsetof'
#define offsetof(TYPE, MEMBER) ((size_t)&((TYPE *)0)->MEMBER)
So just define offsetof unconditionally and directly in terms of
__builtin_offsetof.
Link: https://lkml.kernel.org/r/20220202102147.326672-1-linux@rasmusvillemoes.dk
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Several attributes depend on __CHECKER__, but previously there was no
clue in the tree about when __CHECKER__ might be defined. Add hints at
the most common places (__kernel, __user, __iomem, __bitwise) and in the
sparse documentation.
Link: https://lkml.kernel.org/r/20220310220927.245704-3-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: "Michael S . Tsirkin" <mst@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Previous patches have introduced the compiler attribute btf_type_tag for
__user and __percpu. The availability of this attribute depends on
some CONFIGs and compiler support. This patch refactors the use
of btf_type_tag by introducing BTF_TYPE_TAG, which hides all the
dependencies.
No functional change.
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Hao Luo <haoluo@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220310211655.3173786-1-haoluo@google.com
This is similar to commit 7472d5a642 ("compiler_types: define __user as
__attribute__((btf_type_tag("user")))"), where a type tag "user" was
introduced to identify the pointers that point to user memory. With that
change, the newest compile toolchain can encode __user information into
vmlinux BTF, which can be used by the BPF verifier to enforce safe
program behaviors.
Similarly, we have __percpu attribute, which is mainly used to indicate
memory is allocated in percpu region. The __percpu pointers in kernel
are supposed to be used together with functions like per_cpu_ptr() and
this_cpu_ptr(), which perform necessary calculation on the pointer's
base address. Without the btf_type_tag introduced in this patch,
__percpu pointers will be treated as regular memory pointers in vmlinux
BTF and BPF programs are allowed to directly dereference them, generating
incorrect behaviors. Now with "percpu" btf_type_tag, the BPF verifier is
able to differentiate __percpu pointers from regular pointers and forbids
unexpected behaviors like direct load.
The following is an example similar to the one given in commit
7472d5a642c9:
[$ ~] cat test.c
#define __percpu __attribute__((btf_type_tag("percpu")))
int foo(int __percpu *arg) {
return *arg;
}
[$ ~] clang -O2 -g -c test.c
[$ ~] pahole -JV test.o
...
File test.o:
[1] INT int size=4 nr_bits=32 encoding=SIGNED
[2] TYPE_TAG percpu type_id=1
[3] PTR (anon) type_id=2
[4] FUNC_PROTO (anon) return=1 args=(3 arg)
[5] FUNC foo type_id=4
[$ ~]
for the function argument "int __percpu *arg", its type is described as
PTR -> TYPE_TAG(percpu) -> INT
The kernel can use this information for bpf verification or other
use cases.
Like commit 7472d5a642, this feature requires clang (>= clang14) and
pahole (>= 1.23).
Signed-off-by: Hao Luo <haoluo@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220304191657.981240-3-haoluo@google.com
Add a __diag_ignore_all macro, to ignore warnings for both GCC and LLVM,
without having to specify the compiler type and version. By default, GCC
8 and clang 11 are used. This will be used by bpf subsystem to ignore
-Wmissing-prototypes warning for functions that are meant to be global
functions so that they are in vmlinux BTF, but don't have a prototype.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220304224645.3677453-7-memxor@gmail.com
The __user attribute is currently mainly used by sparse for type checking.
The attribute indicates whether a memory access is in user memory address
space or not. Such information is important during tracing kernel
internal functions or data structures as accessing user memory often
has different mechanisms compared to accessing kernel memory. For example,
the perf-probe needs explicit command line specification to indicate a
particular argument or string in user-space memory ([1], [2], [3]).
Currently, vmlinux BTF is available in kernel with many distributions.
If __user attribute information is available in vmlinux BTF, the explicit
user memory access information from users will not be necessary as
the kernel can figure it out by itself with vmlinux BTF.
Besides the above possible use for perf/probe, another use case is
for bpf verifier. Currently, for bpf BPF_PROG_TYPE_TRACING type of bpf
programs, users can write direct code like
p->m1->m2
and "p" could be a function parameter. Without __user information in BTF,
the verifier will assume p->m1 accessing kernel memory and will generate
normal loads. Let us say "p" actually tagged with __user in the source
code. In such cases, p->m1 is actually accessing user memory and direct
load is not right and may produce incorrect result. For such cases,
bpf_probe_read_user() will be the correct way to read p->m1.
To support encoding __user information in BTF, a new attribute
__attribute__((btf_type_tag("<arbitrary_string>")))
is implemented in clang ([4]). For example, if we have
#define __user __attribute__((btf_type_tag("user")))
during kernel compilation, the attribute "user" information will
be preserved in dwarf. After pahole converting dwarf to BTF, __user
information will be available in vmlinux BTF.
The following is an example with latest upstream clang (clang14) and
pahole 1.23:
[$ ~] cat test.c
#define __user __attribute__((btf_type_tag("user")))
int foo(int __user *arg) {
return *arg;
}
[$ ~] clang -O2 -g -c test.c
[$ ~] pahole -JV test.o
...
[1] INT int size=4 nr_bits=32 encoding=SIGNED
[2] TYPE_TAG user type_id=1
[3] PTR (anon) type_id=2
[4] FUNC_PROTO (anon) return=1 args=(3 arg)
[5] FUNC foo type_id=4
[$ ~]
You can see for the function argument "int __user *arg", its type is
described as
PTR -> TYPE_TAG(user) -> INT
The kernel can use this information for bpf verification or other
use cases.
Current btf_type_tag is only supported in clang (>= clang14) and
pahole (>= 1.23). gcc support is also proposed and under development ([5]).
[1] http://lkml.kernel.org/r/155789874562.26965.10836126971405890891.stgit@devnote2
[2] http://lkml.kernel.org/r/155789872187.26965.4468456816590888687.stgit@devnote2
[3] http://lkml.kernel.org/r/155789871009.26965.14167558859557329331.stgit@devnote2
[4] https://reviews.llvm.org/D111199
[5] https://lore.kernel.org/bpf/0cbeb2fb-1a18-f690-e360-24b1c90c2a91@fb.com/
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220127154600.652613-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Clang and GCC behave a little differently when it comes to the
__no_sanitize_thread attribute, which has valid reasons, and depending
on context either one could be right.
Traditionally, user space ThreadSanitizer [1] still expects instrumented
builtin atomics (to avoid false positives) and __tsan_func_{entry,exit}
(to generate meaningful stack traces), even if the function has the
attribute no_sanitize("thread").
[1] https://clang.llvm.org/docs/ThreadSanitizer.html#attribute-no-sanitize-thread
GCC doesn't follow the same policy (for better or worse), and removes
all kinds of instrumentation if no_sanitize is added. Arguably, since
this may be a problem for user space ThreadSanitizer, we expect this may
change in future.
Since KCSAN != ThreadSanitizer, the likelihood of false positives even
without barrier instrumentation everywhere, is much lower by design.
At least for Clang, however, to fully remove all sanitizer
instrumentation, we must add the disable_sanitizer_instrumentation
attribute, which is available since Clang 14.0.
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Merge misc updates from Andrew Morton:
"257 patches.
Subsystems affected by this patch series: scripts, ocfs2, vfs, and
mm (slab-generic, slab, slub, kconfig, dax, kasan, debug, pagecache,
gup, swap, memcg, pagemap, mprotect, mremap, iomap, tracing, vmalloc,
pagealloc, memory-failure, hugetlb, userfaultfd, vmscan, tools,
memblock, oom-kill, hugetlbfs, migration, thp, readahead, nommu, ksm,
vmstat, madvise, memory-hotplug, rmap, zsmalloc, highmem, zram,
cleanups, kfence, and damon)"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (257 commits)
mm/damon: remove return value from before_terminate callback
mm/damon: fix a few spelling mistakes in comments and a pr_debug message
mm/damon: simplify stop mechanism
Docs/admin-guide/mm/pagemap: wordsmith page flags descriptions
Docs/admin-guide/mm/damon/start: simplify the content
Docs/admin-guide/mm/damon/start: fix a wrong link
Docs/admin-guide/mm/damon/start: fix wrong example commands
mm/damon/dbgfs: add adaptive_targets list check before enable monitor_on
mm/damon: remove unnecessary variable initialization
Documentation/admin-guide/mm/damon: add a document for DAMON_RECLAIM
mm/damon: introduce DAMON-based Reclamation (DAMON_RECLAIM)
selftests/damon: support watermarks
mm/damon/dbgfs: support watermarks
mm/damon/schemes: activate schemes based on a watermarks mechanism
tools/selftests/damon: update for regions prioritization of schemes
mm/damon/dbgfs: support prioritization weights
mm/damon/vaddr,paddr: support pageout prioritization
mm/damon/schemes: prioritize regions within the quotas
mm/damon/selftests: support schemes quotas
mm/damon/dbgfs: support quotas of schemes
...
GCC and Clang can use the "alloc_size" attribute to better inform the
results of __builtin_object_size() (for compile-time constant values).
Clang can additionally use alloc_size to inform the results of
__builtin_dynamic_object_size() (for run-time values).
Because GCC sees the frequent use of struct_size() as an allocator size
argument, and notices it can return SIZE_MAX (the overflow indication),
it complains about these call sites overflowing (since SIZE_MAX is
greater than the default -Walloc-size-larger-than=PTRDIFF_MAX). This
isn't helpful since we already know a SIZE_MAX will be caught at
run-time (this was an intentional design). To deal with this, we must
disable this check as it is both a false positive and redundant. (Clang
does not have this warning option.)
Unfortunately, just checking the -Wno-alloc-size-larger-than is not
sufficient to make the __alloc_size attribute behave correctly under
older GCC versions. The attribute itself must be disabled in those
situations too, as there appears to be no way to reliably silence the
SIZE_MAX constant expression cases for GCC versions less than 9.1:
In file included from ./include/linux/resource_ext.h:11,
from ./include/linux/pci.h:40,
from drivers/net/ethernet/intel/ixgbe/ixgbe.h:9,
from drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c:4:
In function 'kmalloc_node',
inlined from 'ixgbe_alloc_q_vector' at ./include/linux/slab.h:743:9:
./include/linux/slab.h:618:9: error: argument 1 value '18446744073709551615' exceeds maximum object size 9223372036854775807 [-Werror=alloc-size-larger-than=]
return __kmalloc_node(size, flags, node);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./include/linux/slab.h: In function 'ixgbe_alloc_q_vector':
./include/linux/slab.h:455:7: note: in a call to allocation function '__kmalloc_node' declared here
void *__kmalloc_node(size_t size, gfp_t flags, int node) __assume_slab_alignment __malloc;
^~~~~~~~~~~~~~
Specifically:
'-Wno-alloc-size-larger-than' is not correctly handled by GCC < 9.1
https://godbolt.org/z/hqsfG7q84 (doesn't disable)
https://godbolt.org/z/P9jdrPTYh (doesn't admit to not knowing about option)
https://godbolt.org/z/465TPMWKb (only warns when other warnings appear)
'-Walloc-size-larger-than=18446744073709551615' is not handled by GCC < 8.2
https://godbolt.org/z/73hh1EPxz (ignores numeric value)
Since anything marked with __alloc_size would also qualify for marking
with __malloc, just include __malloc along with it to avoid redundant
markings. (Suggested by Linus Torvalds.)
Finally, make sure checkpatch.pl doesn't get confused about finding the
__alloc_size attribute on functions. (Thanks to Joe Perches.)
Link: https://lkml.kernel.org/r/20210930222704.2631604-3-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Daniel Micay <danielmicay@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Dwaipayan Ray <dwaipayanray1@gmail.com>
Cc: Joe Perches <joe@perches.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Alexandre Bounine <alex.bou9@gmail.com>
Cc: Gustavo A. R. Silva <gustavoars@kernel.org>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jing Xiangfeng <jingxiangfeng@huawei.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: kernel test robot <lkp@intel.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
`__compiletime_assert` declares a fake `extern` function
which appears (to the compiler) to be called when the test fails.
Therefore, compilers may emit possibly-uninitialized warnings
in some cases, even if it will be an error anyway (for compilers
supporting the `error` attribute, e.g. GCC and Clang >= 14)
or a link failure (for those that do not, e.g. Clang < 14).
Annotating the fake function as `__noreturn` gives them
the information they need to avoid the warning,
e.g. see https://godbolt.org/z/x1v69jjYY.
Link: https://lore.kernel.org/llvm/202110100514.3h9CI4s0-lkp@intel.com/
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Since all compilers support __builtin_object_size(), and there is only
one user of __compiletime_object_size, remove it to avoid the needless
indirection. This lets Clang reason about check_copy_size() correctly.
Link: https://github.com/ClangBuiltLinux/linux/issues/1179
Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Sedat Dilek <sedat.dilek@gmail.com>
Cc: Will Deacon <will@kernel.org>
Cc: Marco Elver <elver@google.com>
Cc: Arvind Sankar <nivedita@alum.mit.edu>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Gabriel Krisman Bertazi <krisman@collabora.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Clang 14 will add support for __attribute__((__error__(""))) and
__attribute__((__warning__(""))). To make use of these in
__compiletime_error and __compiletime_warning (as used by BUILD_BUG and
friends) for newer clang and detect/fallback for older versions of
clang, move these to compiler_attributes.h and guard them with
__has_attribute preprocessor guards.
Link: https://reviews.llvm.org/D106030
Link: https://bugs.llvm.org/show_bug.cgi?id=16428
Link: https://github.com/ClangBuiltLinux/linux/issues/1173
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
[Reworded, landed in Clang 14]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Merge more updates from Andrew Morton:
"190 patches.
Subsystems affected by this patch series: mm (hugetlb, userfaultfd,
vmscan, kconfig, proc, z3fold, zbud, ras, mempolicy, memblock,
migration, thp, nommu, kconfig, madvise, memory-hotplug, zswap,
zsmalloc, zram, cleanups, kfence, and hmm), procfs, sysctl, misc,
core-kernel, lib, lz4, checkpatch, init, kprobes, nilfs2, hfs,
signals, exec, kcov, selftests, compress/decompress, and ipc"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (190 commits)
ipc/util.c: use binary search for max_idx
ipc/sem.c: use READ_ONCE()/WRITE_ONCE() for use_global_lock
ipc: use kmalloc for msg_queue and shmid_kernel
ipc sem: use kvmalloc for sem_undo allocation
lib/decompressors: remove set but not used variabled 'level'
selftests/vm/pkeys: exercise x86 XSAVE init state
selftests/vm/pkeys: refill shadow register after implicit kernel write
selftests/vm/pkeys: handle negative sys_pkey_alloc() return code
selftests/vm/pkeys: fix alloc_random_pkey() to make it really, really random
kcov: add __no_sanitize_coverage to fix noinstr for all architectures
exec: remove checks in __register_bimfmt()
x86: signal: don't do sas_ss_reset() until we are certain that sigframe won't be abandoned
hfsplus: report create_date to kstat.btime
hfsplus: remove unnecessary oom message
nilfs2: remove redundant continue statement in a while-loop
kprobes: remove duplicated strong free_insn_page in x86 and s390
init: print out unknown kernel parameters
checkpatch: do not complain about positive return values starting with EPOLL
checkpatch: improve the indented label test
checkpatch: scripts/spdxcheck.py now requires python3
...
Until now no compiler supported an attribute to disable coverage
instrumentation as used by KCOV.
To work around this limitation on x86, noinstr functions have their
coverage instrumentation turned into nops by objtool. However, this
solution doesn't scale automatically to other architectures, such as
arm64, which are migrating to use the generic entry code.
Clang [1] and GCC [2] have added support for the attribute recently.
[1] 280333021e
[2] https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=cec4d4a6782c9bd8d071839c50a239c49caca689
The changes will appear in Clang 13 and GCC 12.
Add __no_sanitize_coverage for both compilers, and add it to noinstr.
Note: In the Clang case, __has_feature(coverage_sanitizer) is only true if
the feature is enabled, and therefore we do not require an additional
defined(CONFIG_KCOV) (like in the GCC case where __has_attribute(..) is
always true) to avoid adding redundant attributes to functions if KCOV is
off. That being said, compilers that support the attribute will not
generate errors/warnings if the attribute is redundantly used; however,
where possible let's avoid it as it reduces preprocessed code size and
associated compile-time overheads.
[elver@google.com: Implement __has_feature(coverage_sanitizer) in Clang]
Link: https://lkml.kernel.org/r/20210527162655.3246381-1-elver@google.com
[elver@google.com: add comment explaining __has_feature() in Clang]
Link: https://lkml.kernel.org/r/20210527194448.3470080-1-elver@google.com
Link: https://lkml.kernel.org/r/20210525175819.699786-1-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Will Deacon <will@kernel.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Cc: Arvind Sankar <nivedita@alum.mit.edu>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With CONFIG_CFI_CLANG, the compiler replaces a function address taken
in C code with the address of a local jump table entry, which passes
runtime indirect call checks. However, the compiler won't replace
addresses taken in assembly code, which will result in a CFI failure
if we later jump to such an address in instrumented C code. The code
generated for the non-canonical jump table looks this:
<noncanonical.cfi_jt>: /* In C, &noncanonical points here */
jmp noncanonical
...
<noncanonical>: /* function body */
...
This change adds the __cficanonical attribute, which tells the
compiler to use a canonical jump table for the function instead. This
means the compiler will rename the actual function to <function>.cfi
and points the original symbol to the jump table entry instead:
<canonical>: /* jump table entry */
jmp canonical.cfi
...
<canonical.cfi>: /* function body */
...
As a result, the address taken in assembly, or other non-instrumented
code always points to the jump table and therefore, can be used for
indirect calls in instrumented code without tripping CFI checks.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Bjorn Helgaas <bhelgaas@google.com> # pci.h
Tested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210408182843.1754385-3-samitolvanen@google.com
This change adds support for Clang’s forward-edge Control Flow
Integrity (CFI) checking. With CONFIG_CFI_CLANG, the compiler
injects a runtime check before each indirect function call to ensure
the target is a valid function with the correct static type. This
restricts possible call targets and makes it more difficult for
an attacker to exploit bugs that allow the modification of stored
function pointers. For more details, see:
https://clang.llvm.org/docs/ControlFlowIntegrity.html
Clang requires CONFIG_LTO_CLANG to be enabled with CFI to gain
visibility to possible call targets. Kernel modules are supported
with Clang’s cross-DSO CFI mode, which allows checking between
independently compiled components.
With CFI enabled, the compiler injects a __cfi_check() function into
the kernel and each module for validating local call targets. For
cross-module calls that cannot be validated locally, the compiler
calls the global __cfi_slowpath_diag() function, which determines
the target module and calls the correct __cfi_check() function. This
patch includes a slowpath implementation that uses __module_address()
to resolve call targets, and with CONFIG_CFI_CLANG_SHADOW enabled, a
shadow map that speeds up module look-ups by ~3x.
Clang implements indirect call checking using jump tables and
offers two methods of generating them. With canonical jump tables,
the compiler renames each address-taken function to <function>.cfi
and points the original symbol to a jump table entry, which passes
__cfi_check() validation. This isn’t compatible with stand-alone
assembly code, which the compiler doesn’t instrument, and would
result in indirect calls to assembly code to fail. Therefore, we
default to using non-canonical jump tables instead, where the compiler
generates a local jump table entry <function>.cfi_jt for each
address-taken function, and replaces all references to the function
with the address of the jump table entry.
Note that because non-canonical jump table addresses are local
to each component, they break cross-module function address
equality. Specifically, the address of a global function will be
different in each module, as it's replaced with the address of a local
jump table entry. If this address is passed to a different module,
it won’t match the address of the same function taken there. This
may break code that relies on comparing addresses passed from other
components.
CFI checking can be disabled in a function with the __nocfi attribute.
Additionally, CFI can be disabled for an entire compilation unit by
filtering out CC_FLAGS_CFI.
By default, CFI failures result in a kernel panic to stop a potential
exploit. CONFIG_CFI_PERMISSIVE enables a permissive mode, where the
kernel prints out a rate-limited warning instead, and allows execution
to continue. This option is helpful for locating type mismatches, but
should only be enabled during development.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210408182843.1754385-2-samitolvanen@google.com
- Remove CONFIG_ENABLE_MUST_CHECK (Masahiro Yamada)
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Merge tag 'compiler-attributes-for-linus-v5.11' of git://github.com/ojeda/linux
Pull ENABLE_MUST_CHECK removal from Miguel Ojeda:
"Remove CONFIG_ENABLE_MUST_CHECK (Masahiro Yamada)"
Note that this removes the config option by making the must-check
unconditional, not by removing must check itself.
* tag 'compiler-attributes-for-linus-v5.11' of git://github.com/ojeda/linux:
Compiler Attributes: remove CONFIG_ENABLE_MUST_CHECK
These are a couple of compiler warning fixes to make 'make W=2'
less noisy, as well as some fixes to code comments in asm-generic.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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Merge tag 'asm-generic-cleanup-5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic
Pull asm-generic cleanups from Arnd Bergmann:
"These are a couple of compiler warning fixes to make 'make W=2' less
noisy, as well as some fixes to code comments in asm-generic"
* tag 'asm-generic-cleanup-5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
syscalls: Fix file comments for syscalls implemented in kernel/sys.c
ctype.h: remove duplicate isdigit() helper
qspinlock: use signed temporaries for cmpxchg
asm-generic: fix ffs -Wshadow warning
asm-generic: percpu: avoid Wshadow warning
asm-generic/sembuf: Update architecture related information in comment
Revert commit cebc04ba9a ("add CONFIG_ENABLE_MUST_CHECK").
A lot of warn_unused_result warnings existed in 2006, but until now
they have been fixed thanks to people doing allmodconfig tests.
Our goal is to always enable __must_check where appropriate, so this
CONFIG option is no longer needed.
I see a lot of defconfig (arch/*/configs/*_defconfig) files having:
# CONFIG_ENABLE_MUST_CHECK is not set
I did not touch them for now since it would be a big churn. If arch
maintainers want to clean them up, please go ahead.
While I was here, I also moved __must_check to compiler_attributes.h
from compiler_types.h
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Jason A. Donenfeld <Jason@zx2c4.com>
Acked-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
[Moved addition in compiler_attributes.h to keep it sorted]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Commit 3193c0836 ("bpf: Disable GCC -fgcse optimization for
___bpf_prog_run()") introduced a __no_fgcse macro that expands to a
function scope __attribute__((optimize("-fno-gcse"))), to disable a
GCC specific optimization that was causing trouble on x86 builds, and
was not expected to have any positive effect in the first place.
However, as the GCC manual documents, __attribute__((optimize))
is not for production use, and results in all other optimization
options to be forgotten for the function in question. This can
cause all kinds of trouble, but in one particular reported case,
it causes -fno-asynchronous-unwind-tables to be disregarded,
resulting in .eh_frame info to be emitted for the function.
This reverts commit 3193c0836, and instead, it disables the -fgcse
optimization for the entire source file, but only when building for
X86 using GCC with CONFIG_BPF_JIT_ALWAYS_ON disabled. Note that the
original commit states that CONFIG_RETPOLINE=n triggers the issue,
whereas CONFIG_RETPOLINE=y performs better without the optimization,
so it is kept disabled in both cases.
Fixes: 3193c0836f ("bpf: Disable GCC -fgcse optimization for ___bpf_prog_run()")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/lkml/CAMuHMdUg0WJHEcq6to0-eODpXPOywLot6UD2=GFHpzoj_hCoBQ@mail.gmail.com/
Link: https://lore.kernel.org/bpf/20201028171506.15682-2-ardb@kernel.org
gcc warns a few thousand times about the isdigit() shadow:
include/linux/ctype.h:26:19: warning: declaration of 'isdigit' shadows a built-in function [-Wshadow]
As there is already a compiler builtin, just use that, and make
it clear we do that by defining a macro. Unfortunately, clang
does not have the isdigit() builtin, so this has to be conditional.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
__chk_user_ptr() & __chk_io_ptr() are dummy extern functions which
only exist to enforce the typechecking of __user or __iomem pointers
in macros when using sparse.
This typechecking is done by inserting a call to these functions.
But the presence of these calls can inhibit some simplifications
and so influence the result of sparse's analysis of context/locking.
Fix this by changing these calls into static inline calls with
an empty body.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
- Removal of the tremendously unpopular read_barrier_depends() barrier,
which is a NOP on all architectures apart from Alpha, in favour of
allowing architectures to override READ_ONCE() and do whatever dance
they need to do to ensure address dependencies provide LOAD ->
LOAD/STORE ordering. This work also offers a potential solution if
compilers are shown to convert LOAD -> LOAD address dependencies into
control dependencies (e.g. under LTO), as weakly ordered architectures
will effectively be able to upgrade READ_ONCE() to smp_load_acquire().
The latter case is not used yet, but will be discussed further at LPC.
- Make the MSI/IOMMU input/output ID translation PCI agnostic, augment
the MSI/IOMMU ACPI/OF ID mapping APIs to accept an input ID
bus-specific parameter and apply the resulting changes to the device
ID space provided by the Freescale FSL bus.
- arm64 support for TLBI range operations and translation table level
hints (part of the ARMv8.4 architecture version).
- Time namespace support for arm64.
- Export the virtual and physical address sizes in vmcoreinfo for
makedumpfile and crash utilities.
- CPU feature handling cleanups and checks for programmer errors
(overlapping bit-fields).
- ACPI updates for arm64: disallow AML accesses to EFI code regions and
kernel memory.
- perf updates for arm64.
- Miscellaneous fixes and cleanups, most notably PLT counting
optimisation for module loading, recordmcount fix to ignore
relocations other than R_AARCH64_CALL26, CMA areas reserved for
gigantic pages on 16K and 64K configurations.
- Trivial typos, duplicate words.
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 and cross-arch updates from Catalin Marinas:
"Here's a slightly wider-spread set of updates for 5.9.
Going outside the usual arch/arm64/ area is the removal of
read_barrier_depends() series from Will and the MSI/IOMMU ID
translation series from Lorenzo.
The notable arm64 updates include ARMv8.4 TLBI range operations and
translation level hint, time namespace support, and perf.
Summary:
- Removal of the tremendously unpopular read_barrier_depends()
barrier, which is a NOP on all architectures apart from Alpha, in
favour of allowing architectures to override READ_ONCE() and do
whatever dance they need to do to ensure address dependencies
provide LOAD -> LOAD/STORE ordering.
This work also offers a potential solution if compilers are shown
to convert LOAD -> LOAD address dependencies into control
dependencies (e.g. under LTO), as weakly ordered architectures will
effectively be able to upgrade READ_ONCE() to smp_load_acquire().
The latter case is not used yet, but will be discussed further at
LPC.
- Make the MSI/IOMMU input/output ID translation PCI agnostic,
augment the MSI/IOMMU ACPI/OF ID mapping APIs to accept an input ID
bus-specific parameter and apply the resulting changes to the
device ID space provided by the Freescale FSL bus.
- arm64 support for TLBI range operations and translation table level
hints (part of the ARMv8.4 architecture version).
- Time namespace support for arm64.
- Export the virtual and physical address sizes in vmcoreinfo for
makedumpfile and crash utilities.
- CPU feature handling cleanups and checks for programmer errors
(overlapping bit-fields).
- ACPI updates for arm64: disallow AML accesses to EFI code regions
and kernel memory.
- perf updates for arm64.
- Miscellaneous fixes and cleanups, most notably PLT counting
optimisation for module loading, recordmcount fix to ignore
relocations other than R_AARCH64_CALL26, CMA areas reserved for
gigantic pages on 16K and 64K configurations.
- Trivial typos, duplicate words"
Link: http://lkml.kernel.org/r/20200710165203.31284-1-will@kernel.org
Link: http://lkml.kernel.org/r/20200619082013.13661-1-lorenzo.pieralisi@arm.com
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (82 commits)
arm64: use IRQ_STACK_SIZE instead of THREAD_SIZE for irq stack
arm64/mm: save memory access in check_and_switch_context() fast switch path
arm64: sigcontext.h: delete duplicated word
arm64: ptrace.h: delete duplicated word
arm64: pgtable-hwdef.h: delete duplicated words
bus: fsl-mc: Add ACPI support for fsl-mc
bus/fsl-mc: Refactor the MSI domain creation in the DPRC driver
of/irq: Make of_msi_map_rid() PCI bus agnostic
of/irq: make of_msi_map_get_device_domain() bus agnostic
dt-bindings: arm: fsl: Add msi-map device-tree binding for fsl-mc bus
of/device: Add input id to of_dma_configure()
of/iommu: Make of_map_rid() PCI agnostic
ACPI/IORT: Add an input ID to acpi_dma_configure()
ACPI/IORT: Remove useless PCI bus walk
ACPI/IORT: Make iort_msi_map_rid() PCI agnostic
ACPI/IORT: Make iort_get_device_domain IRQ domain agnostic
ACPI/IORT: Make iort_match_node_callback walk the ACPI namespace for NC
arm64: enable time namespace support
arm64/vdso: Restrict splitting VVAR VMA
arm64/vdso: Handle faults on timens page
...
The kernel test robot reports that moving READ_ONCE() out into its own
header breaks a W=1 build for parisc, which is relying on the definition
of compiletime_assert() being available:
| In file included from ./arch/parisc/include/generated/asm/rwonce.h:1,
| from ./include/asm-generic/barrier.h:16,
| from ./arch/parisc/include/asm/barrier.h:29,
| from ./arch/parisc/include/asm/atomic.h:11,
| from ./include/linux/atomic.h:7,
| from kernel/locking/percpu-rwsem.c:2:
| ./arch/parisc/include/asm/atomic.h: In function 'atomic_read':
| ./include/asm-generic/rwonce.h:36:2: error: implicit declaration of function 'compiletime_assert' [-Werror=implicit-function-declaration]
| 36 | compiletime_assert(__native_word(t) || sizeof(t) == sizeof(long long), \
| | ^~~~~~~~~~~~~~~~~~
| ./include/asm-generic/rwonce.h:49:2: note: in expansion of macro 'compiletime_assert_rwonce_type'
| 49 | compiletime_assert_rwonce_type(x); \
| | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| ./arch/parisc/include/asm/atomic.h:73:9: note: in expansion of macro 'READ_ONCE'
| 73 | return READ_ONCE((v)->counter);
| | ^~~~~~~~~
Move these macros into compiler_types.h, so that they are available to
READ_ONCE() and friends.
Link: http://lists.infradead.org/pipermail/linux-arm-kernel/2020-July/587094.html
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Will Deacon <will@kernel.org>
I realize that we fairly recently raised it to 4.8, but the fact is, 4.9
is a much better minimum version to target.
We have a number of workarounds for actual bugs in pre-4.9 gcc versions
(including things like internal compiler errors on ARM), but we also
have some syntactic workarounds for lacking features.
In particular, raising the minimum to 4.9 means that we can now just
assume _Generic() exists, which is likely the much better replacement
for a lot of very convoluted built-time magic with conditionals on
sizeof and/or __builtin_choose_expr() with same_type() etc.
Using _Generic also means that you will need to have a very recent
version of 'sparse', but thats easy to build yourself, and much less of
a hassle than some old gcc version can be.
The latest (in a long string) of reasons for minimum compiler version
upgrades was commit 5435f73d5c ("efi/x86: Fix build with gcc 4").
Ard points out that RHEL 7 uses gcc-4.8, but the people who stay back on
old RHEL versions persumably also don't build their own kernels anyway.
And maybe they should cross-built or just have a little side affair with
a newer compiler?
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently, address spaces in warnings are displayed as '<asn:X>' with
'X' being the address space's arbitrary number.
But since sparse v0.6.0-rc1 (late December 2018), sparse allows you to
define the address spaces using an identifier instead of a number. This
identifier is then directly used in the warnings.
So, use the identifiers '__user', '__iomem', '__percpu' & '__rcu' for
the corresponding address spaces. The default address space, __kernel,
being not displayed in warnings, stays defined as '0'.
With this change, warnings that used to be displayed as:
cast removes address space '<asn:1>' of expression
... void [noderef] <asn:2> *
will now be displayed as:
cast removes address space '__user' of expression
... void [noderef] __iomem *
This also moves the __kernel annotation to be the first one, since it is
quite different from the others because it's the default one, and so:
- it's never displayed
- it's normally not needed, nor in type annotations, nor in cast
between address spaces. The only time it's needed is when it's
combined with a typeof to express "the same type as this one but
without the address space"
- it can't be defined with a name, '0' must be used.
So, it seemed strange to me to have it in the middle of the other
ones.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Acked-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Linus Torvalds