Commit 7043679a authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Thomas Gleixner
Browse files

x86/debug: Remove handle_debug(.user) argument 



The handle_debug(.user) argument is used to terminate the #DB handler early
for the INT1-from-kernel case, since the kernel doesn't use INT1.

Remove the argument and handle this explicitly in #DB-from-kernel.

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Tested-by: default avatarDaniel Thompson <daniel.thompson@linaro.org>
Acked-by: default avatarAndy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20200902133200.907020598@infradead.org
parent 20a6e35a

arch/x86/kernel/traps.c

+10 −11
Original line number Diff line number Diff line
@@ -783,25 +783,18 @@ static __always_inline unsigned long debug_read_clear_dr6(void) 
 *

 * May run on IST stack.

 */

static void handle_debug(struct pt_regs *regs, unsigned long dr6, bool user)

static void handle_debug(struct pt_regs *regs, unsigned long dr6)

{

	struct task_struct *tsk = current;

	bool user_icebp;

	int si_code;



	/*

	 * If DR6 is zero, no point in trying to handle it. The kernel is

	 * not using INT1.

	 */

	if (!user && !dr6)

		return;



	/*

	 * 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 = user && !dr6;

	user_icebp = !dr6;



	/* Store the virtualized DR6 value */

	tsk->thread.debugreg6 = dr6;
@@ -874,7 +867,13 @@ static __always_inline void exc_debug_kernel(struct pt_regs *regs, 
	if (kprobe_debug_handler(regs))

		goto out;



	handle_debug(regs, dr6, false);

	/*

	 * The kernel doesn't use INT1

	 */

	if (!dr6)

		goto out;



	handle_debug(regs, dr6);



out:

	instrumentation_end();
@@ -904,7 +903,7 @@ static __always_inline void exc_debug_user(struct pt_regs *regs, 
	irqentry_enter_from_user_mode(regs);

	instrumentation_begin();



	handle_debug(regs, dr6, true);

	handle_debug(regs, dr6);



	instrumentation_end();

	irqentry_exit_to_user_mode(regs);

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