linux-kernel - [PATCH v3 2/7] x86-64, kgdb: clear GDB

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Date:	Sat, 13 Aug 2016 12:38:17 -0400
From:	Brian Gerst <brgerst@...il.com>
To:	x86@...nel.org, linux-kernel@...r.kernel.org
Cc:	Ingo Molnar <mingo@...nel.org>, "H. Peter Anvin" <hpa@...or.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Denys Vlasenko <dvlasenk@...hat.com>,
	Andy Lutomirski <luto@...capital.net>,
	Borislav Petkov <bp@...e.de>,
	Thomas Gleixner <tglx@...utronix.de>,
	Josh Poimboeuf <jpoimboe@...hat.com>
Subject: [PATCH v3 2/7] 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>
---
 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;
-- 
2.5.5