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From: Peter Zijlstra <peterz@infradead.org>
To: x86@kernel.org
Cc: linux-kernel@vger.kernel.org, Kyle Huey <me@kylehuey.com>,
	Alexandre Chartre <alexandre.chartre@oracle.com>,
	Robert O'Callahan <rocallahan@gmail.com>,
	"Paul E. McKenney" <paulmck@kernel.org>,
	Frederic Weisbecker <frederic@kernel.org>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Sean Christopherson <sean.j.christopherson@intel.com>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Petr Mladek <pmladek@suse.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Joel Fernandes <joel@joelfernandes.org>,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	Juergen Gross <jgross@suse.com>, Brian Gerst <brgerst@gmail.com>,
	Andy Lutomirski <luto@kernel.org>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>
Subject: [RFC][PATCH 5/7] x86/debug: Remove handle_debug(.user) argument
Date: Thu, 20 Aug 2020 12:38:37 +0200	[thread overview]
Message-ID: <20200820104905.353155876@infradead.org> (raw)
In-Reply-To: <20200820103832.486877479@infradead.org>


Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 arch/x86/kernel/traps.c |   21 ++++++++++-----------
 1 file changed, 10 insertions(+), 11 deletions(-)

--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -783,25 +783,18 @@ static __always_inline unsigned long deb
  *
  * 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_ke
 		regs->flags &= ~X86_EFLAGS_TF;
 	}
 
-	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_us
 	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);



  parent reply	other threads:[~2020-08-20 10:54 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-20 10:38 [RFC][PATCH 0/7] x86/debug: Untangle handle_debug() Peter Zijlstra
2020-08-20 10:38 ` [PATCH 1/7] x86/debug: Allow a single level of #DB recursion Peter Zijlstra
2020-08-26 13:54   ` Sasha Levin
2020-08-20 10:38 ` [RFC][PATCH 2/7] x86/debug: Sync BTF earlier Peter Zijlstra
2020-08-21  2:25   ` Thomas Gleixner
2020-08-20 10:38 ` [RFC][PATCH 3/7] x86/debug: Move kprobe_debug_handler() into exc_debug_kernel() Peter Zijlstra
2020-08-21 13:54   ` Masami Hiramatsu
2020-08-20 10:38 ` [RFC][PATCH 4/7] x86/debug: Move historical SYSENTER junk " Peter Zijlstra
2020-08-20 14:45   ` Brian Gerst
2020-08-20 15:08     ` peterz
2020-08-20 15:16       ` Josh Poimboeuf
2020-08-20 15:21         ` peterz
2020-08-20 16:17           ` Josh Poimboeuf
2020-08-20 16:34             ` peterz
2020-08-20 16:43               ` Andy Lutomirski
2020-08-20 17:21                 ` Josh Poimboeuf
2020-08-20 18:19                 ` peterz
2020-08-20 15:28   ` Daniel Thompson
2020-08-20 15:51     ` peterz
2020-08-21 10:19     ` peterz
2020-08-21 13:31       ` Daniel Thompson
2020-08-20 10:38 ` Peter Zijlstra [this message]
2020-08-20 10:38 ` [RFC][PATCH 6/7] x86/debug: Simplify #DB signal code Peter Zijlstra
2020-08-20 10:38 ` [RFC][PATCH 7/7] x86/debug: Move cond_local_irq_enable() block into exc_debug_user() Peter Zijlstra
2020-08-21  2:29 ` [RFC][PATCH 0/7] x86/debug: Untangle handle_debug() Thomas Gleixner

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