[PATCH v2 08/10] x86/entry: Only allocate space for SYSENTER_stack if needed

From: Andy Lutomirski
Date: Sun Mar 06 2016 - 00:53:18 EST


The SYSENTER stack is only used on 32-bit kernels. Remove it in
64-bit kernels.

(We may end up using it down the road on 64-bit kernels. If so,
we'll re-enable it for CONFIG_IA32_EMULATION.)

Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>
---
arch/x86/include/asm/processor.h | 2 ++
1 file changed, 2 insertions(+)

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index ecb410310e70..7cd01b71b5bd 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -297,10 +297,12 @@ struct tss_struct {
*/
unsigned long io_bitmap[IO_BITMAP_LONGS + 1];

+#ifdef CONFIG_X86_32
/*
* Space for the temporary SYSENTER stack:
*/
unsigned long SYSENTER_stack[64];
+#endif

} ____cacheline_aligned;

--
2.5.0