From: Gayatri Vasudevan <gayatri.vasudevan@oracle.com>
Date: Mon, 17 Sep 2018 18:03:30 +0000 (-0700)
Subject: x86/ia32: Restore r8 correctly in 32bit SYSCALL instruction entry.
X-Git-Tag: v4.1.12-124.31.3~506
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=af7594868ae722ef5abdfba2aa61fbd02aa2e67a;p=users%2Fjedix%2Flinux-maple.git

x86/ia32: Restore r8 correctly in 32bit SYSCALL instruction entry.

This commit fixes a bug in a previous commit
8e69671028ac ("x86/ia32: Adds code hygiene for 32bit SYSCALL instruction
entry.")

SAVE_EXTRA_REGS does not save the r8 register. r8 is rather saved in
pt_regs->sp before it is cleared. So, retrieve r8 from pt_regs->sp.

Orabug: 28529706

Signed-off-by: Gayatri Vasudevan <gayatri.vasudevan@oracle.com>
Reviewed-by: Bert Barbe <bert.barbe@oracle.com>
Signed-off-by: Brian Maly <brian.maly@oracle.com>
---

diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index 6a52527eac06..bf4cd7336c6d 100644
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -410,7 +410,7 @@ ENTRY(ia32_cstar_target)
 	 * 32bit zero extended
 	 */
 	ASM_STAC
-	movq	R8(%rsp),%r8
+	movq	RSP(%rsp),%r8
 1:	movl	(%r8),%r9d
 	_ASM_EXTABLE(1b,ia32_badarg)
 	ASM_CLAC