lkml.org 
[lkml]   [2015]   [Mar]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[tip:x86/asm] x86/asm/entry/64/compat: Change the 32-bit sysenter code to use sp0
Commit-ID:  9d0c914c60f4d3123debb653340dc1f7cf44939d
Gitweb: http://git.kernel.org/tip/9d0c914c60f4d3123debb653340dc1f7cf44939d
Author: Andy Lutomirski <luto@amacapital.net>
AuthorDate: Thu, 5 Mar 2015 19:19:04 -0800
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 6 Mar 2015 08:32:58 +0100

x86/asm/entry/64/compat: Change the 32-bit sysenter code to use sp0

The ia32 sysenter code loaded the top of the kernel stack into
rsp by loading kernel_stack and then adjusting it. It can be
simplified to just read sp0 directly.

This requires the addition of a new asm-offsets entry for sp0.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/88ff9006163d296a0665338585c36d9bfb85235d.1425611534.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/ia32/ia32entry.S | 3 +--
arch/x86/kernel/asm-offsets_64.c | 1 +
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index ed97463..719db63 100644
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -113,8 +113,7 @@ ENTRY(ia32_sysenter_target)
CFI_DEF_CFA rsp,0
CFI_REGISTER rsp,rbp
SWAPGS_UNSAFE_STACK
- movq PER_CPU_VAR(kernel_stack), %rsp
- addq $(KERNEL_STACK_OFFSET),%rsp
+ movq PER_CPU_VAR(init_tss + TSS_sp0), %rsp
/*
* No need to follow this irqs on/off section: the syscall
* disabled irqs, here we enable it straight after entry:
diff --git a/arch/x86/kernel/asm-offsets_64.c b/arch/x86/kernel/asm-offsets_64.c
index fdcbb4d..5ce6f2d 100644
--- a/arch/x86/kernel/asm-offsets_64.c
+++ b/arch/x86/kernel/asm-offsets_64.c
@@ -81,6 +81,7 @@ int main(void)
#undef ENTRY

OFFSET(TSS_ist, tss_struct, x86_tss.ist);
+ OFFSET(TSS_sp0, tss_struct, x86_tss.sp0);
BLANK();

DEFINE(__NR_syscall_max, sizeof(syscalls_64) - 1);

\
 
 \ /
  Last update: 2015-03-06 10:01    [W:0.102 / U:0.688 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site