linux-kernel - [tip:x86/asm] sched/x86/64, kgdb: Clear GDB

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Message-ID: <tip-163630191ecb0dd9e4146d3c910045aba1cfeec1@git.kernel.org>
Date:   Wed, 24 Aug 2016 06:07:44 -0700
From:   tip-bot for Brian Gerst <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, dvlasenk@...hat.com, hpa@...or.com,
        peterz@...radead.org, brgerst@...il.com, luto@...nel.org,
        bp@...en8.de, jason.wessel@...driver.com, mingo@...nel.org,
        jpoimboe@...hat.com, tglx@...utronix.de,
        torvalds@...ux-foundation.org
Subject: [tip:x86/asm] sched/x86/64, kgdb: Clear GDB_PS on 64-bit

Commit-ID:  163630191ecb0dd9e4146d3c910045aba1cfeec1
Gitweb:     http://git.kernel.org/tip/163630191ecb0dd9e4146d3c910045aba1cfeec1
Author:     Brian Gerst <brgerst@...il.com>
AuthorDate: Sat, 13 Aug 2016 12:38:17 -0400
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Wed, 24 Aug 2016 12:27:40 +0200

sched/x86/64, kgdb: Clear GDB_PS on 64-bit

switch_to() no longer saves EFLAGS, so it's bogus to look for it on the
stack.  Set it to zero like 32-bit.

Signed-off-by: Brian Gerst <brgerst@...il.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@...hat.com>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Denys Vlasenko <dvlasenk@...hat.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Jason Wessel <jason.wessel@...driver.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Link: http://lkml.kernel.org/r/1471106302-10159-3-git-send-email-brgerst@gmail.com
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/kernel/kgdb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c
index fe649a5..5e3f294 100644
--- a/arch/x86/kernel/kgdb.c
+++ b/arch/x86/kernel/kgdb.c
@@ -176,7 +176,7 @@ void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
 	gdb_regs[GDB_FS]	= 0xFFFF;
 	gdb_regs[GDB_GS]	= 0xFFFF;
 #else
-	gdb_regs32[GDB_PS]	= *(unsigned long *)(p->thread.sp + 8);
+	gdb_regs32[GDB_PS]	= 0;
 	gdb_regs32[GDB_CS]	= __KERNEL_CS;
 	gdb_regs32[GDB_SS]	= __KERNEL_DS;
 	gdb_regs[GDB_R8]	= 0;