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x86/entry: Fix NMI vs IRQ state tracking

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While the nmi_enter() users did
trace_hardirqs_{off_prepare,on_finish}() there was no matching
lockdep_hardirqs_*() calls to complete the picture.

Introduce idtentry_{enter,exit}_nmi() to enable proper IRQ state
tracking across the NMIs.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/20200623083721.216740948@infradead.org
This commit is contained in:
Peter Zijlstra
2020-05-27 15:50:29 +02:00
parent 859d069ee1
commit ba1f2b2eaa
5 changed files with 70 additions and 29 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
arch/x86/kernel/nmi.c
View File

@@ -330,7 +330,6 @@ static noinstr void default_do_nmi(struct pt_regs *regs)
__this_cpu_write(last_nmi_rip, regs->ip);
instrumentation_begin();
trace_hardirqs_off_finish();
handled = nmi_handle(NMI_LOCAL, regs);
__this_cpu_add(nmi_stats.normal, handled);
@@ -417,8 +416,6 @@ static noinstr void default_do_nmi(struct pt_regs *regs)
unknown_nmi_error(reason, regs);
out:
if (regs->flags & X86_EFLAGS_IF)
trace_hardirqs_on_prepare();
instrumentation_end();
}
@@ -478,6 +475,8 @@ static DEFINE_PER_CPU(unsigned long, nmi_dr7);
DEFINE_IDTENTRY_RAW(exc_nmi)
{
bool irq_state;
if (IS_ENABLED(CONFIG_SMP) && arch_cpu_is_offline(smp_processor_id()))
return;
@@ -491,14 +490,14 @@ nmi_restart:
this_cpu_write(nmi_dr7, local_db_save());
nmi_enter();
irq_state = idtentry_enter_nmi(regs);
inc_irq_stat(__nmi_count);
if (!ignore_nmis)
default_do_nmi(regs);
nmi_exit();
idtentry_exit_nmi(regs, irq_state);
local_db_restore(this_cpu_read(nmi_dr7));

17
arch/x86/kernel/traps.c
View File

@@ -403,7 +403,7 @@ DEFINE_IDTENTRY_DF(exc_double_fault)
}
#endif
nmi_enter();
idtentry_enter_nmi(regs);
instrumentation_begin();
notify_die(DIE_TRAP, str, regs, error_code, X86_TRAP_DF, SIGSEGV);
@@ -649,15 +649,12 @@ DEFINE_IDTENTRY_RAW(exc_int3)
instrumentation_end();
idtentry_exit_user(regs);
} else {
nmi_enter();
bool irq_state = idtentry_enter_nmi(regs);
instrumentation_begin();
trace_hardirqs_off_finish();
if (!do_int3(regs))
die("int3", regs, 0);
if (regs->flags & X86_EFLAGS_IF)
trace_hardirqs_on_prepare();
instrumentation_end();
nmi_exit();
idtentry_exit_nmi(regs, irq_state);
}
}
@@ -865,9 +862,8 @@ out:
static __always_inline void exc_debug_kernel(struct pt_regs *regs,
unsigned long dr6)
{
nmi_enter();
bool irq_state = idtentry_enter_nmi(regs);
instrumentation_begin();
trace_hardirqs_off_finish();
/*
* If something gets miswired and we end up here for a user mode
@@ -884,10 +880,8 @@ static __always_inline void exc_debug_kernel(struct pt_regs *regs,
handle_debug(regs, dr6, false);
if (regs->flags & X86_EFLAGS_IF)
trace_hardirqs_on_prepare();
instrumentation_end();
nmi_exit();
idtentry_exit_nmi(regs, irq_state);
}
static __always_inline void exc_debug_user(struct pt_regs *regs,
@@ -903,6 +897,7 @@ static __always_inline void exc_debug_user(struct pt_regs *regs,
instrumentation_begin();
handle_debug(regs, dr6, true);
instrumentation_end();
idtentry_exit_user(regs);
}