diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2020-04-06 15:55:06 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2020-06-11 15:14:58 +0200 |
| commit | f051f697955049c7cf10a635ab8149aa619243b2 (patch) | |
| tree | f4d5678ab79116e38137bd3401d2847b20d2a321 /arch/x86/kernel | |
| parent | 6271fef00b3489690e52ce95edbc378357513547 (diff) | |
x86/nmi: Protect NMI entry against instrumentation
Mark all functions in the fragile code parts noinstr or force inlining so
they can't be instrumented.
Also make the hardware latency tracer invocation explicit outside of
non-instrumentable section.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20200505135314.716186134@linutronix.de
Diffstat (limited to 'arch/x86/kernel')
| -rw-r--r-- | arch/x86/kernel/cpu/common.c | 6 | ||||
| -rw-r--r-- | arch/x86/kernel/nmi.c | 15 |
2 files changed, 11 insertions, 10 deletions
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 8be042df12c3..f4645f9ff9cb 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1709,21 +1709,19 @@ void syscall_init(void) DEFINE_PER_CPU(int, debug_stack_usage); DEFINE_PER_CPU(u32, debug_idt_ctr); -void debug_stack_set_zero(void) +noinstr void debug_stack_set_zero(void) { this_cpu_inc(debug_idt_ctr); load_current_idt(); } -NOKPROBE_SYMBOL(debug_stack_set_zero); -void debug_stack_reset(void) +noinstr void debug_stack_reset(void) { if (WARN_ON(!this_cpu_read(debug_idt_ctr))) return; if (this_cpu_dec_return(debug_idt_ctr) == 0) load_current_idt(); } -NOKPROBE_SYMBOL(debug_stack_reset); #else /* CONFIG_X86_64 */ diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c index 3b05cc802abb..3052c78f03aa 100644 --- a/arch/x86/kernel/nmi.c +++ b/arch/x86/kernel/nmi.c @@ -303,7 +303,7 @@ NOKPROBE_SYMBOL(unknown_nmi_error); static DEFINE_PER_CPU(bool, swallow_nmi); static DEFINE_PER_CPU(unsigned long, last_nmi_rip); -static void default_do_nmi(struct pt_regs *regs) +static noinstr void default_do_nmi(struct pt_regs *regs) { unsigned char reason = 0; int handled; @@ -329,6 +329,8 @@ static void default_do_nmi(struct pt_regs *regs) __this_cpu_write(last_nmi_rip, regs->ip); + instrumentation_begin(); + handled = nmi_handle(NMI_LOCAL, regs); __this_cpu_add(nmi_stats.normal, handled); if (handled) { @@ -342,7 +344,7 @@ static void default_do_nmi(struct pt_regs *regs) */ if (handled > 1) __this_cpu_write(swallow_nmi, true); - return; + goto out; } /* @@ -374,7 +376,7 @@ static void default_do_nmi(struct pt_regs *regs) #endif __this_cpu_add(nmi_stats.external, 1); raw_spin_unlock(&nmi_reason_lock); - return; + goto out; } raw_spin_unlock(&nmi_reason_lock); @@ -412,8 +414,10 @@ static void default_do_nmi(struct pt_regs *regs) __this_cpu_add(nmi_stats.swallow, 1); else unknown_nmi_error(reason, regs); + +out: + instrumentation_end(); } -NOKPROBE_SYMBOL(default_do_nmi); /* * NMIs can page fault or hit breakpoints which will cause it to lose @@ -485,7 +489,7 @@ static DEFINE_PER_CPU(unsigned long, nmi_cr2); */ static DEFINE_PER_CPU(int, update_debug_stack); -static bool notrace is_debug_stack(unsigned long addr) +static noinstr bool is_debug_stack(unsigned long addr) { struct cea_exception_stacks *cs = __this_cpu_read(cea_exception_stacks); unsigned long top = CEA_ESTACK_TOP(cs, DB); @@ -500,7 +504,6 @@ static bool notrace is_debug_stack(unsigned long addr) */ return addr >= bot && addr < top; } -NOKPROBE_SYMBOL(is_debug_stack); #endif DEFINE_IDTENTRY_NMI(exc_nmi) |