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Subject[PATCH 1/7] x86/vm86: Clean up saved_fs/gs
Date
There is no need to save FS and non-lazy GS outside the 32-bit regs.  Lazy GS
still needs to be saved because it wasn't saved on syscall entry. Save it in
the gs slot of regs32, which is present but unused.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
---
arch/x86/include/asm/processor.h | 2 --
arch/x86/kernel/vm86_32.c | 6 ++----
2 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 43e6519..f4e4e3f 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -410,8 +410,6 @@ struct thread_struct {
unsigned long v86flags;
unsigned long v86mask;
unsigned long saved_sp0;
- unsigned int saved_fs;
- unsigned int saved_gs;
#endif
/* IO permissions: */
unsigned long *io_bitmap_ptr;
diff --git a/arch/x86/kernel/vm86_32.c b/arch/x86/kernel/vm86_32.c
index fc9db6e..761a2f9 100644
--- a/arch/x86/kernel/vm86_32.c
+++ b/arch/x86/kernel/vm86_32.c
@@ -159,8 +159,7 @@ struct pt_regs *save_v86_state(struct kernel_vm86_regs *regs)

ret = KVM86->regs32;

- ret->fs = current->thread.saved_fs;
- set_user_gs(ret, current->thread.saved_gs);
+ lazy_load_gs(ret->gs);

return ret;
}
@@ -315,8 +314,7 @@ static void do_sys_vm86(struct kernel_vm86_struct *info, struct task_struct *tsk
*/
info->regs32->ax = VM86_SIGNAL;
tsk->thread.saved_sp0 = tsk->thread.sp0;
- tsk->thread.saved_fs = info->regs32->fs;
- tsk->thread.saved_gs = get_user_gs(info->regs32);
+ lazy_save_gs(info->regs32->gs);

tss = &per_cpu(cpu_tss, get_cpu());
tsk->thread.sp0 = (unsigned long) &info->VM86_TSS_ESP0;
--
2.4.3


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