x86/debug: Simplify #DB signal code (4182e943) · Commits · 戴 / test

arch/x86/kernel/traps.c

+9 −6

Original line number	Diff line number	Diff line
		@@ -786,15 +786,14 @@ static __always_inline unsigned long debug_read_clear_dr6(void)
		static void handle_debug(struct pt_regs *regs, unsigned long dr6)
		{
		struct task_struct *tsk = current;
		bool user_icebp;
		int si_code;
		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.
		*/
		user_icebp = !dr6;
		icebp = !dr6;

		/* Store the virtualized DR6 value */
		tsk->thread.debugreg6 = dr6;
		@@ -813,6 +812,11 @@ static void handle_debug(struct pt_regs *regs, unsigned long dr6)
		goto out;
		}

		/*
		* Reload dr6, the notifier might have changed it.
		*/
		dr6 = tsk->thread.debugreg6;

		if (WARN_ON_ONCE((dr6 & DR_STEP) && !user_mode(regs))) {
		/*
		* Historical junk that used to handle SYSENTER single-stepping.
		@@ -825,9 +829,8 @@ static void handle_debug(struct pt_regs *regs, unsigned long dr6)
		regs->flags &= ~X86_EFLAGS_TF;
		}

		si_code = get_si_code(tsk->thread.debugreg6);
		if (tsk->thread.debugreg6 & (DR_STEP \| DR_TRAP_BITS) \|\| user_icebp)
		send_sigtrap(regs, 0, si_code);
		if (dr6 & (DR_STEP \| DR_TRAP_BITS) \|\| icebp)
		send_sigtrap(regs, 0, get_si_code(dr6));

		out:
		cond_local_irq_disable(regs);