linux-kernel - [RFC][PATCH -tip 2/5 V2] x86: fix kernel_trap

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Date:	Fri, 20 Mar 2009 21:33:40 -0400
From:	Masami Hiramatsu <mhiramat@...hat.com>
To:	Ingo Molnar <mingo@...e.hu>,
	Harvey Harrison <harvey.harrison@...il.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Jan Blunck <jblunck@...e.de>
CC:	LKML <linux-kernel@...r.kernel.org>,
	systemtap-ml <systemtap@...rces.redhat.com>,
	Ananth N Mavinakayanahalli <ananth@...ibm.com>,
	Steven Rostedt <rostedt@...dmis.org>,
	Frederic Weisbecker <fweisbec@...il.com>
Subject: [RFC][PATCH -tip 2/5 V2] x86: fix kernel_trap_sp()

Use &regs->sp instead of regs for getting the top of stack in kernel mode.
(on x86-64, regs->sp always points the top of stack)

Signed-off-by: Masami Hiramatsu <mhiramat@...hat.com>
Cc: Harvey Harrison <harvey.harrison@...il.com>
Cc: Ingo Molnar <mingo@...e.hu>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Jan Blunck <jblunck@...e.de>
---

 arch/x86/include/asm/ptrace.h |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)


diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h
index e304b66..aed0894 100644
--- a/arch/x86/include/asm/ptrace.h
+++ b/arch/x86/include/asm/ptrace.h
@@ -187,14 +187,14 @@ static inline int v8086_mode(struct pt_regs *regs)

 /*
  * X86_32 CPUs don't save ss and esp if the CPU is already in kernel mode
- * when it traps.  So regs will be the current sp.
+ * when it traps.  So &regs->sp will be the current sp.
  *
  * This is valid only for kernel mode traps.
  */
 static inline unsigned long kernel_trap_sp(struct pt_regs *regs)
 {
 #ifdef CONFIG_X86_32
-	return (unsigned long)regs;
+	return (unsigned long)&regs->sp;
 #else
 	return regs->sp;
 #endif
-- 
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America) Inc.
Software Solutions Division

e-mail: mhiramat@...hat.com


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