user/sven/linux.git/include/linux/compiler.h, branch v5.8.10

rcu: Fixup noinstr warnings

2020-06-25T15:24:32Z

A KCSAN build revealed we have explicit annoations through atomic_*() usage, switch to arch_atomic_*() for the respective functions. vmlinux.o: warning: objtool: rcu_nmi_exit()+0x4d: call to __kcsan_check_access() leaves .noinstr.text section vmlinux.o: warning: objtool: rcu_dynticks_eqs_enter()+0x25: call to __kcsan_check_access() leaves .noinstr.text section vmlinux.o: warning: objtool: rcu_nmi_enter()+0x4f: call to __kcsan_check_access() leaves .noinstr.text section vmlinux.o: warning: objtool: rcu_dynticks_eqs_exit()+0x2a: call to __kcsan_check_access() leaves .noinstr.text section vmlinux.o: warning: objtool: __rcu_is_watching()+0x25: call to __kcsan_check_access() leaves .noinstr.text section Additionally, without the NOP in instrumentation_begin(), objtool would not detect the lack of the 'else instrumentation_begin();' branch in rcu_nmi_enter(). Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Paul E. McKenney

compiler.h: Move function attributes to compiler_types.h

2020-06-11T18:04:04Z

Cleanup and move the KASAN and KCSAN related function attributes to compiler_types.h, where the rest of the same kind live. No functional change intended. Signed-off-by: Marco Elver Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra (Intel) Acked-by: Will Deacon Link: https://lkml.kernel.org/r/20200521142047.169334-11-elver@google.com

compiler.h: Avoid nested statement expression in data_race()

2020-06-11T18:04:03Z

It appears that compilers have trouble with nested statement expressions. Therefore, remove one level of statement expression nesting from the data_race() macro. This will help avoiding potential problems in the future as its usage increases. Reported-by: Borislav Petkov Reported-by: Nathan Chancellor Signed-off-by: Marco Elver Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra (Intel) Acked-by: Will Deacon Tested-by: Nick Desaulniers Link: https://lkml.kernel.org/r/20200520221712.GA21166@zn.tnic Link: https://lkml.kernel.org/r/20200521142047.169334-10-elver@google.com

compiler.h: Remove data_race() and unnecessary checks from {READ,WRITE}_ONCE()

2020-06-11T18:04:03Z

The volatile accesses no longer need to be wrapped in data_race() because compilers that emit instrumentation distinguishing volatile accesses are required for KCSAN. Consequently, the explicit kcsan_check_atomic*() are no longer required either since the compiler emits instrumentation distinguishing the volatile accesses. Finally, simplify __READ_ONCE_SCALAR() and remove __WRITE_ONCE_SCALAR(). [ bp: Convert commit message to passive voice. ] Signed-off-by: Marco Elver Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra (Intel) Acked-by: Will Deacon Link: https://lkml.kernel.org/r/20200521142047.169334-9-elver@google.com

kcsan: Remove 'noinline' from __no_kcsan_or_inline

2020-06-11T18:04:02Z

Some compilers incorrectly inline small __no_kcsan functions, which then results in instrumenting the accesses. For this reason, the 'noinline' attribute was added to __no_kcsan_or_inline. All known versions of GCC are affected by this. Supported versions of Clang are unaffected, and never inline a no_sanitize function. However, the attribute 'noinline' in __no_kcsan_or_inline causes unexpected code generation in functions that are __no_kcsan and call a __no_kcsan_or_inline function. In certain situations it is expected that the __no_kcsan_or_inline function is actually inlined by the __no_kcsan function, and *no* calls are emitted. By removing the 'noinline' attribute, give the compiler the ability to inline and generate the expected code in __no_kcsan functions. Signed-off-by: Marco Elver Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra (Intel) Acked-by: Will Deacon Link: https://lkml.kernel.org/r/CANpmjNNOpJk0tprXKB_deiNAv_UmmORf1-2uajLhnLWQQ1hvoA@mail.gmail.com Link: https://lkml.kernel.org/r/20200521142047.169334-6-elver@google.com

Rebase locking/kcsan to locking/urgent

2020-06-11T18:02:46Z

Merge the state of the locking kcsan branch before the read/write_once() and the atomics modifications got merged. Squash the fallout of the rebase on top of the read/write once and atomic fallback work into the merge. The history of the original branch is preserved in tag locking-kcsan-2020-06-02. Signed-off-by: Thomas Gleixner

Merge branch 'rwonce/rework' of git://git.kernel.org/pub/scm/linux/kernel/git/will/linux

2020-06-10T21:46:54Z

Pull READ/WRITE_ONCE rework from Will Deacon: "This the READ_ONCE rework I've been working on for a while, which bumps the minimum GCC version and improves code-gen on arm64 when stack protector is enabled" [ Side note: I'm _really_ tempted to raise the minimum gcc version to 4.9, so that we can just say that we require _Generic() support. That would allow us to more cleanly handle a lot of the cases where we depend on very complex macros with 'sizeof' or __builtin_choose_expr() with __builtin_types_compatible_p() etc. This branch has a workaround for sparse not handling _Generic(), either, but that was already fixed in the sparse development branch, so it's really just gcc-4.9 that we'd require. - Linus ] * 'rwonce/rework' of git://git.kernel.org/pub/scm/linux/kernel/git/will/linux: compiler_types.h: Use unoptimized __unqual_scalar_typeof for sparse compiler_types.h: Optimize __unqual_scalar_typeof compilation time compiler.h: Enforce that READ_ONCE_NOCHECK() access size is sizeof(long) compiler-types.h: Include naked type in __pick_integer_type() match READ_ONCE: Fix comment describing 2x32-bit atomicity gcov: Remove old GCC 3.4 support arm64: barrier: Use '__unqual_scalar_typeof' for acquire/release macros locking/barriers: Use '__unqual_scalar_typeof' for load-acquire macros READ_ONCE: Drop pointer qualifiers when reading from scalar types READ_ONCE: Enforce atomicity for {READ,WRITE}_ONCE() memory accesses READ_ONCE: Simplify implementations of {READ,WRITE}_ONCE() arm64: csum: Disable KASAN for do_csum() fault_inject: Don't rely on "return value" from WRITE_ONCE() net: tls: Avoid assigning 'const' pointer to non-const pointer netfilter: Avoid assigning 'const' pointer to non-const pointer compiler/gcc: Raise minimum GCC version for kernel builds to 4.8

compiler.h: Enforce that READ_ONCE_NOCHECK() access size is sizeof(long)

2020-06-05T10:19:46Z

READ_ONCE_NOCHECK() unconditionally performs a sizeof(long)-sized access, so enforce that the size of the pointed-to object that we are loading from is the same size as 'long'. Reported-by: Marco Elver Signed-off-by: Will Deacon

READ_ONCE: Fix comment describing 2x32-bit atomicity

2020-06-05T10:02:44Z

READ_ONCE() permits 64-bit accesses on 32-bit architectures, since this crops up in a few places and is generally harmless because either the upper bits are always zero (e.g. for a virtual address or 32-bit time_t) or the architecture provides 64-bit atomicity anyway. Update the corresponding comment above compiletime_assert_rwonce_type(), which incorrectly states that 32-bit x86 provides 64-bit atomicity, and instead reference 32-bit Armv7 with LPAE. Cc: Thomas Gleixner Cc: Peter Zijlstra Reported-by: Jann Horn Signed-off-by: Will Deacon

Merge tag 'core-kprobes-2020-06-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2020-06-01T19:45:04Z

Pull kprobes updates from Ingo Molnar: "Various kprobes updates, mostly centered around cleaning up the no-instrumentation logic. Instead of the current per debug facility blacklist, use the more generic .noinstr.text approach, combined with a 'noinstr' marker for functions. Also add instrumentation_begin()/end() to better manage the exact place in entry code where instrumentation may be used. And add a kprobes blacklist for modules" * tag 'core-kprobes-2020-06-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: kprobes: Prevent probes in .noinstr.text section vmlinux.lds.h: Create section for protection against instrumentation samples/kprobes: Add __kprobes and NOKPROBE_SYMBOL() for handlers. kprobes: Support NOKPROBE_SYMBOL() in modules kprobes: Support __kprobes blacklist in modules kprobes: Lock kprobe_mutex while showing kprobe_blacklist