diff options
author | Marco Elver <elver@google.com> | 2020-05-21 16:20:42 +0200 |
---|---|---|
committer | Thomas Gleixner <tglx@linutronix.de> | 2020-06-11 20:04:00 +0200 |
commit | 0e1aa5b62160500bb2ed3150367fba83c0a194e5 (patch) | |
tree | c892fcffdfdab1e1406cb4ee0aa43c031e335ae3 /scripts/Makefile.kcsan | |
parent | 17168f5c1bef4ec7c239e2dd5e3e60b862727dd4 (diff) | |
download | linux-0e1aa5b62160500bb2ed3150367fba83c0a194e5.tar.gz linux-0e1aa5b62160500bb2ed3150367fba83c0a194e5.tar.bz2 linux-0e1aa5b62160500bb2ed3150367fba83c0a194e5.zip |
kcsan: Restrict supported compilers
The first version of Clang that supports -tsan-distinguish-volatile will
be able to support KCSAN. The first Clang release to do so, will be
Clang 11. This is due to satisfying all the following requirements:
1. Never emit calls to __tsan_func_{entry,exit}.
2. __no_kcsan functions should not call anything, not even
kcsan_{enable,disable}_current(), when using __{READ,WRITE}_ONCE => Requires
leaving them plain!
3. Support atomic_{read,set}*() with KCSAN, which rely on
arch_atomic_{read,set}*() using __{READ,WRITE}_ONCE() => Because of
#2, rely on Clang 11's -tsan-distinguish-volatile support. We will
double-instrument atomic_{read,set}*(), but that's reasonable given
it's still lower cost than the data_race() variant due to avoiding 2
extra calls (kcsan_{en,dis}able_current() calls).
4. __always_inline functions inlined into __no_kcsan functions are never
instrumented.
5. __always_inline functions inlined into instrumented functions are
instrumented.
6. __no_kcsan_or_inline functions may be inlined into __no_kcsan functions =>
Implies leaving 'noinline' off of __no_kcsan_or_inline.
7. Because of #6, __no_kcsan and __no_kcsan_or_inline functions should never be
spuriously inlined into instrumented functions, causing the accesses of the
__no_kcsan function to be instrumented.
Older versions of Clang do not satisfy #3. The latest GCC currently
doesn't support at least #1, #3, and #7.
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lkml.kernel.org/r/CANpmjNMTsY_8241bS7=XAfqvZHFLrVEkv_uM4aDUWE_kh3Rvbw@mail.gmail.com
Link: https://lkml.kernel.org/r/20200521142047.169334-7-elver@google.com
Diffstat (limited to 'scripts/Makefile.kcsan')
0 files changed, 0 insertions, 0 deletions