The following commit has been merged into the x86/entry branch of tip: Commit-ID: f0b67c39c190e19bc1604a13bcc985c4445a4b2f Gitweb: https://git.kernel.org/tip/f0b67c39c190e19bc1604a13bcc985c4445a4b2f Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx> AuthorDate: Wed, 02 Sep 2020 15:25:57 +02:00 Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx> CommitterDate: Fri, 04 Sep 2020 15:12:53 +02:00 x86/debug: Move cond_local_irq_enable() block into exc_debug_user() 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) <peterz@xxxxxxxxxxxxx> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Tested-by: Daniel Thompson <daniel.thompson@xxxxxxxxxx> Link: https://lore.kernel.org/r/20200902133201.094265982@xxxxxxxxxxxxx --- arch/x86/kernel/traps.c | 58 ++++++++++++++++++++-------------------- 1 file changed, 29 insertions(+), 29 deletions(-) diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 2605686..682af24 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -783,17 +783,10 @@ static __always_inline unsigned long debug_read_clear_dr6(void) * * 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; - bool icebp; - - /* - * 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. - */ - icebp = !*dr6; /* Store the virtualized DR6 value */ tsk->thread.debugreg6 = *dr6; @@ -801,26 +794,9 @@ static bool handle_debug(struct pt_regs *regs, unsigned long *dr6) 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 & (DR_STEP | DR_TRAP_BITS) || icebp) - send_sigtrap(regs, 0, get_si_code(*dr6)); - -out: - cond_local_irq_disable(regs); - return false; } @@ -864,7 +840,7 @@ static __always_inline void exc_debug_kernel(struct pt_regs *regs, if (!dr6) goto out; - if (handle_debug(regs, &dr6)) + if (notify_debug(regs, &dr6)) goto out; if (WARN_ON_ONCE(dr6 & DR_STEP)) { @@ -889,6 +865,8 @@ out: static __always_inline void exc_debug_user(struct pt_regs *regs, unsigned long dr6) { + bool icebp; + /* * If something gets miswired and we end up here for a kernel mode * #DB, we will malfunction. @@ -907,8 +885,30 @@ static __always_inline void exc_debug_user(struct pt_regs *regs, irqentry_enter_from_user_mode(regs); instrumentation_begin(); - handle_debug(regs, &dr6); + /* + * 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. + */ + icebp = !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 & (DR_STEP | DR_TRAP_BITS) || icebp) + send_sigtrap(regs, 0, get_si_code(dr6)); + +out_irq: + local_irq_disable(); +out: instrumentation_end(); irqentry_exit_to_user_mode(regs); }
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