[tip:x86/asm] sched/x86/64, kgdb: Clear GDB_PS on 64-bit

[tip-bot for Brian Gerst]

Commit-ID:  163630191ecb0dd9e4146d3c910045aba1cfeec1
Gitweb:     http://git.kernel.org/tip/163630191ecb0dd9e4146d3c910045aba1cfeec1
Author:     Brian Gerst <brgerst@xxxxxxxxx>
AuthorDate: Sat, 13 Aug 2016 12:38:17 -0400
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
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@xxxxxxxxx>
Reviewed-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Jason Wessel <jason.wessel@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1471106302-10159-3-git-send-email-brgerst@xxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 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;