iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity
fc37a3b8b4
linux/include
History
Marco Elver 540540d06e kcov: add __no_sanitize_coverage to fix noinstr for all architectures 
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>
2021-07-01 11:06:06 -07:00
..
acpi
asm-generic kernel.h: split out panic and oops helpers 2021-07-01 11:06:04 -07:00
clocksource
crypto
drm
dt-bindings dt-bindings: connector: Add PD rev 2.0 VDO definition 2021-06-04 11:43:01 +02:00
keys integrity-v5.13 2021-05-01 15:32:18 -07:00
kunit kunit: make test->lock irq safe 2021-06-29 10:53:46 -07:00
kvm
linux kcov: add __no_sanitize_coverage to fix noinstr for all architectures 2021-07-01 11:06:06 -07:00
math-emu
media
memory
misc
net net: inline function get_net_ns_by_fd if NET_NS is disabled 2021-06-15 11:00:45 -07:00
pcmcia
ras
rdma
scsi
soc
sound ASoC: Fixes for v5.13 2021-05-25 08:58:01 +02:00
target
trace include/trace/events/vmscan.h: remove mm_vmscan_inactive_list_is_low 2021-06-30 20:47:28 -07:00
uapi mm/madvise: introduce MADV_POPULATE_(READ|WRITE) to prefault page tables 2021-06-30 20:47:30 -07:00
vdso
video
xen xen/arm: move xen_swiotlb_detect to arm/swiotlb-xen.h 2021-05-14 15:52:05 +02:00