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authorH. Peter Anvin <hpa@linux.intel.com>2012-05-08 22:22:37 +0400
committerH. Peter Anvin <hpa@linux.intel.com>2012-05-08 22:48:03 +0400
commite5684ec438a094bec0f7d5c52652c0901b48b613 (patch)
tree8cc3cf787a582977ff08ed578907d6df7dbc7e6e /arch/x86/realmode/rm/trampoline_32.S
parent968ff9ee56f1e3ed4ff4a6d10185865dc77d8f7e (diff)
downloadlinux-e5684ec438a094bec0f7d5c52652c0901b48b613.tar.xz
x86, realmode: Replace open-coded ljmpw with a macro
We cannot code an ljmpw to the real-mode segment directly, because gas refuses to assemble an ljmp with a symbolic segment. Instead of open-coding it everywhere, define a macro and use it for this case. This is specifically an ljmpw from a 16-bit segment. This is okay, as one should never enter real mode from a 32-bit segment: if one do, the CPU ends up in a bizarre (and useless) mode sometimes called "unreal mode" where segments behave like real mode but the default address and operand sizes is 32 bits. Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Link: http://lkml.kernel.org/r/1336501366-28617-15-git-send-email-jarkko.sakkinen@intel.com
Diffstat (limited to 'arch/x86/realmode/rm/trampoline_32.S')
-rw-r--r--arch/x86/realmode/rm/trampoline_32.S5
1 files changed, 2 insertions, 3 deletions
diff --git a/arch/x86/realmode/rm/trampoline_32.S b/arch/x86/realmode/rm/trampoline_32.S
index 1315ef48dbf1..279f82ef7a9e 100644
--- a/arch/x86/realmode/rm/trampoline_32.S
+++ b/arch/x86/realmode/rm/trampoline_32.S
@@ -29,6 +29,7 @@
#include <linux/init.h>
#include <asm/segment.h>
#include <asm/page_types.h>
+#include "realmode.h"
.text
.code16
@@ -38,9 +39,7 @@
trampoline_data:
wbinvd # Needed for NUMA-Q should be harmless for others
- .byte 0xea # ljmpw
- .word 1f # Offset
- .word real_mode_seg # Segment
+ LJMPW_RM(1f)
1:
mov %cs, %ax # Code and data in the same place
mov %ax, %ds