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| author | Dmitry Vyukov <dvyukov@google.com> | 2024-06-11 10:50:30 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-10-04 17:29:58 +0300 |
| commit | 32e93cae4dc456ad731ff9cd8b29bc8e9716ad5f (patch) | |
| tree | 3de625a5b2aa6ef4f5b9fb9fde7e7c4695bcefc9 /arch | |
| parent | d5c5afdb9e1efe7e7061e3688356bdae50bfd174 (diff) | |
| download | linux-32e93cae4dc456ad731ff9cd8b29bc8e9716ad5f.tar.xz | |
x86/entry: Remove unwanted instrumentation in common_interrupt()
[ Upstream commit 477d81a1c47a1b79b9c08fc92b5dea3c5143800b ]
common_interrupt() and related variants call kvm_set_cpu_l1tf_flush_l1d(),
which is neither marked noinstr nor __always_inline.
So compiler puts it out of line and adds instrumentation to it. Since the
call is inside of instrumentation_begin/end(), objtool does not warn about
it.
The manifestation is that KCOV produces spurious coverage in
kvm_set_cpu_l1tf_flush_l1d() in random places because the call happens when
preempt count is not yet updated to say that the kernel is in an interrupt.
Mark kvm_set_cpu_l1tf_flush_l1d() as __always_inline and move it out of the
instrumentation_begin/end() section. It only calls __this_cpu_write()
which is already safe to call in noinstr contexts.
Fixes: 6368558c3710 ("x86/entry: Provide IDTENTRY_SYSVEC")
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexander Potapenko <glider@google.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/3f9a1de9e415fcb53d07dc9e19fa8481bb021b1b.1718092070.git.dvyukov@google.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/include/asm/hardirq.h | 8 | ||||
| -rw-r--r-- | arch/x86/include/asm/idtentry.h | 6 |
2 files changed, 9 insertions, 5 deletions
diff --git a/arch/x86/include/asm/hardirq.h b/arch/x86/include/asm/hardirq.h index 66837b8c67f1..f2e245741afc 100644 --- a/arch/x86/include/asm/hardirq.h +++ b/arch/x86/include/asm/hardirq.h @@ -63,7 +63,11 @@ extern u64 arch_irq_stat(void); #define local_softirq_pending_ref pcpu_hot.softirq_pending #if IS_ENABLED(CONFIG_KVM_INTEL) -static inline void kvm_set_cpu_l1tf_flush_l1d(void) +/* + * This function is called from noinstr interrupt contexts + * and must be inlined to not get instrumentation. + */ +static __always_inline void kvm_set_cpu_l1tf_flush_l1d(void) { __this_cpu_write(irq_stat.kvm_cpu_l1tf_flush_l1d, 1); } @@ -78,7 +82,7 @@ static __always_inline bool kvm_get_cpu_l1tf_flush_l1d(void) return __this_cpu_read(irq_stat.kvm_cpu_l1tf_flush_l1d); } #else /* !IS_ENABLED(CONFIG_KVM_INTEL) */ -static inline void kvm_set_cpu_l1tf_flush_l1d(void) { } +static __always_inline void kvm_set_cpu_l1tf_flush_l1d(void) { } #endif /* IS_ENABLED(CONFIG_KVM_INTEL) */ #endif /* _ASM_X86_HARDIRQ_H */ diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h index e2585f61082c..10603e185111 100644 --- a/arch/x86/include/asm/idtentry.h +++ b/arch/x86/include/asm/idtentry.h @@ -212,8 +212,8 @@ __visible noinstr void func(struct pt_regs *regs, \ irqentry_state_t state = irqentry_enter(regs); \ u32 vector = (u32)(u8)error_code; \ \ + kvm_set_cpu_l1tf_flush_l1d(); \ instrumentation_begin(); \ - kvm_set_cpu_l1tf_flush_l1d(); \ run_irq_on_irqstack_cond(__##func, regs, vector); \ instrumentation_end(); \ irqentry_exit(regs, state); \ @@ -250,7 +250,6 @@ static void __##func(struct pt_regs *regs); \ \ static __always_inline void instr_##func(struct pt_regs *regs) \ { \ - kvm_set_cpu_l1tf_flush_l1d(); \ run_sysvec_on_irqstack_cond(__##func, regs); \ } \ \ @@ -258,6 +257,7 @@ __visible noinstr void func(struct pt_regs *regs) \ { \ irqentry_state_t state = irqentry_enter(regs); \ \ + kvm_set_cpu_l1tf_flush_l1d(); \ instrumentation_begin(); \ instr_##func (regs); \ instrumentation_end(); \ @@ -288,7 +288,6 @@ static __always_inline void __##func(struct pt_regs *regs); \ static __always_inline void instr_##func(struct pt_regs *regs) \ { \ __irq_enter_raw(); \ - kvm_set_cpu_l1tf_flush_l1d(); \ __##func (regs); \ __irq_exit_raw(); \ } \ @@ -297,6 +296,7 @@ __visible noinstr void func(struct pt_regs *regs) \ { \ irqentry_state_t state = irqentry_enter(regs); \ \ + kvm_set_cpu_l1tf_flush_l1d(); \ instrumentation_begin(); \ instr_##func (regs); \ instrumentation_end(); \ |