]> git.baikalelectronics.ru Git - kernel.git/commit
x86/cpu: Elide KCSAN for cpu_has() and friends
authorPeter Zijlstra <peterz@infradead.org>
Mon, 2 May 2022 10:15:23 +0000 (12:15 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Tue, 14 Jun 2022 16:36:23 +0000 (18:36 +0200)
commitc41d03c248d4f07d385996406e4966894d4e5cb3
tree2a192cfb77629e985459d4f235c401aefe31c1da
parentef9b9260e16302191d4d50139927713ba927070c
x86/cpu: Elide KCSAN for cpu_has() and friends

[ Upstream commit 178716709418936a16c364fb8c96d9bbb6915c04 ]

As x86 uses the <asm-generic/bitops/instrumented-*.h> headers, the
regular forms of all bitops are instrumented with explicit calls to
KASAN and KCSAN checks. As these are explicit calls, these are not
suppressed by the noinstr function attribute.

This can result in calls to those check functions in noinstr code, which
objtool warns about:

vmlinux.o: warning: objtool: enter_from_user_mode+0x24: call to __kcsan_check_access() leaves .noinstr.text section
vmlinux.o: warning: objtool: syscall_enter_from_user_mode+0x28: call to __kcsan_check_access() leaves .noinstr.text section
vmlinux.o: warning: objtool: syscall_enter_from_user_mode_prepare+0x24: call to __kcsan_check_access() leaves .noinstr.text section
vmlinux.o: warning: objtool: irqentry_enter_from_user_mode+0x24: call to __kcsan_check_access() leaves .noinstr.text section

Prevent this by using the arch_*() bitops, which are the underlying
bitops without explciit instrumentation.

[null: Changelog]
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220502111216.290518605@infradead.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
arch/x86/include/asm/cpufeature.h