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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@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Daniel Thompson <daniel.thompson@linaro.org> Link: https://lore.kernel.org/r/20200902133201.094265982@infradead.org
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parent
4eb5acc391
commit
f0b67c39c1
1 changed files with 29 additions and 29 deletions
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@ -783,17 +783,10 @@ static __always_inline unsigned long debug_read_clear_dr6(void)
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*
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* May run on IST stack.
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*/
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static bool handle_debug(struct pt_regs *regs, unsigned long *dr6)
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static bool notify_debug(struct pt_regs *regs, unsigned long *dr6)
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{
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struct task_struct *tsk = current;
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bool icebp;
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/*
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* If dr6 has no reason to give us about the origin of this trap,
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* then it's very likely the result of an icebp/int01 trap.
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* User wants a sigtrap for that.
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*/
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icebp = !*dr6;
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/* Store the virtualized DR6 value */
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tsk->thread.debugreg6 = *dr6;
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@ -801,26 +794,9 @@ static bool handle_debug(struct pt_regs *regs, unsigned long *dr6)
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if (notify_die(DIE_DEBUG, "debug", regs, (long)dr6, 0, SIGTRAP) == NOTIFY_STOP)
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return true;
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/* It's safe to allow irq's after DR6 has been saved */
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cond_local_irq_enable(regs);
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if (v8086_mode(regs)) {
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handle_vm86_trap((struct kernel_vm86_regs *) regs, 0,
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X86_TRAP_DB);
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goto out;
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}
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/*
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* Reload dr6, the notifier might have changed it.
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*/
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/* Reload the DR6 value, the notifier might have changed it */
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*dr6 = tsk->thread.debugreg6;
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if (*dr6 & (DR_STEP | DR_TRAP_BITS) || icebp)
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send_sigtrap(regs, 0, get_si_code(*dr6));
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out:
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cond_local_irq_disable(regs);
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return false;
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}
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@ -864,7 +840,7 @@ static __always_inline void exc_debug_kernel(struct pt_regs *regs,
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if (!dr6)
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goto out;
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if (handle_debug(regs, &dr6))
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if (notify_debug(regs, &dr6))
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goto out;
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if (WARN_ON_ONCE(dr6 & DR_STEP)) {
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@ -889,6 +865,8 @@ static __always_inline void exc_debug_kernel(struct pt_regs *regs,
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static __always_inline void exc_debug_user(struct pt_regs *regs,
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unsigned long dr6)
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{
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bool icebp;
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/*
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* If something gets miswired and we end up here for a kernel mode
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* #DB, we will malfunction.
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@ -907,8 +885,30 @@ static __always_inline void exc_debug_user(struct pt_regs *regs,
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irqentry_enter_from_user_mode(regs);
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instrumentation_begin();
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handle_debug(regs, &dr6);
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/*
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* If dr6 has no reason to give us about the origin of this trap,
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* then it's very likely the result of an icebp/int01 trap.
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* User wants a sigtrap for that.
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*/
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icebp = !dr6;
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if (notify_debug(regs, &dr6))
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goto out;
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/* It's safe to allow irq's after DR6 has been saved */
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local_irq_enable();
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if (v8086_mode(regs)) {
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handle_vm86_trap((struct kernel_vm86_regs *)regs, 0, X86_TRAP_DB);
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goto out_irq;
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}
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if (dr6 & (DR_STEP | DR_TRAP_BITS) || icebp)
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send_sigtrap(regs, 0, get_si_code(dr6));
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out_irq:
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local_irq_disable();
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out:
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instrumentation_end();
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irqentry_exit_to_user_mode(regs);
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}
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