Messages in this thread Patch in this message | | | Date | Mon, 2 May 2022 15:09:16 +0200 | From | Peter Zijlstra <> | Subject | [PATCH v2 3/3] jump_label,noinstr: Avoid instrumentation for JUMP_LABEL=n builds |
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Subject: jump_label,noinstr: Avoid instrumentation for JUMP_LABEL=n builds From: Peter Zijlstra <peterz@infradead.org> Date: Mon May 2 12:30:20 CEST 2022
When building x86_64 with JUMP_LABEL=n it's possible for instrumentation to sneak into noinstr:
vmlinux.o: warning: objtool: exit_to_user_mode+0x14: call to static_key_count.constprop.0() leaves .noinstr.text section vmlinux.o: warning: objtool: syscall_exit_to_user_mode+0x2d: call to static_key_count.constprop.0() leaves .noinstr.text section vmlinux.o: warning: objtool: irqentry_exit_to_user_mode+0x1b: call to static_key_count.constprop.0() leaves .noinstr.text section
Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> --- include/linux/jump_label.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/include/linux/jump_label.h +++ b/include/linux/jump_label.h @@ -256,9 +256,9 @@ extern void static_key_disable_cpuslocke #include <linux/atomic.h> #include <linux/bug.h> -static inline int static_key_count(struct static_key *key) +static __always_inline int static_key_count(struct static_key *key) { - return atomic_read(&key->enabled); + return arch_atomic_read(&key->enabled.count); } static __always_inline void jump_label_init(void)
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