The cond_local_irq_enable() block, dealing with vm86 and sending signals is only relevant for #DB-from-user, move it there.
This then reduces handle_debug() to only the notifier call, so rename it to notify_debug(). Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> --- arch/x86/kernel/traps.c | 51 +++++++++++++++++++++++------------------------- 1 file changed, 25 insertions(+), 26 deletions(-) --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -783,7 +783,8 @@ static __always_inline unsigned long deb * * May run on IST stack. */ -static bool handle_debug(struct pt_regs *regs, unsigned long *dr6) + +static bool notify_debug(struct pt_regs *regs, unsigned long *dr6) { struct task_struct *tsk = current; @@ -793,31 +794,9 @@ static bool handle_debug(struct pt_regs if (notify_die(DIE_DEBUG, "debug", regs, (long)dr6, 0, SIGTRAP) == NOTIFY_STOP) return true; - /* It's safe to allow irq's after DR6 has been saved */ - cond_local_irq_enable(regs); - - if (v8086_mode(regs)) { - handle_vm86_trap((struct kernel_vm86_regs *) regs, 0, - X86_TRAP_DB); - goto out; - } - - /* - * Reload dr6, the notifier might have changed it. - */ + /* Reload the DR6 value, the notifier might have changed it */ *dr6 = tsk->thread.debugreg6; - /* - * If dr6 has no reason to give us about the origin of this trap, - * then it's very likely the result of an icebp/int01 trap. - * User wants a sigtrap for that. - */ - if (*dr6 & (DR_STEP | DR_TRAP_BITS) || !*dr6) - send_sigtrap(regs, 0, get_si_code(*dr6)); - -out: - cond_local_irq_disable(regs); - return false; } @@ -861,7 +840,7 @@ static __always_inline void exc_debug_ke if (!dr6) goto out; - if (handle_debug(regs, &dr6)) + if (notify_debug(regs, &dr6)) goto out; if (WARN_ON_ONCE(dr6 & DR_STEP)) { @@ -904,8 +883,28 @@ static __always_inline void exc_debug_us irqentry_enter_from_user_mode(regs); instrumentation_begin(); - handle_debug(regs, &dr6); + if (notify_debug(regs, &dr6)) + goto out; + + /* It's safe to allow irq's after DR6 has been saved */ + local_irq_enable(); + + if (v8086_mode(regs)) { + handle_vm86_trap((struct kernel_vm86_regs *)regs, 0, X86_TRAP_DB); + goto out_irq; + } + /* + * If dr6 has no reason to give us about the origin of this trap, + * then it's very likely the result of an icebp/int01 trap. + * User wants a sigtrap for that. + */ + if (dr6 & (DR_STEP | DR_TRAP_BITS) || !dr6) + send_sigtrap(regs, 0, get_si_code(dr6)); + +out_irq: + local_irq_disable(); +out: instrumentation_end(); irqentry_exit_to_user_mode(regs); }