Re: [PATCH] [34/58] x86_64: ia32entry adjustments

From: Jeff Garzik
Date: Thu Jul 19 2007 - 10:47:32 EST


Andi Kleen wrote:
From: "Jan Beulich" <jbeulich@xxxxxxxxxx>
Consolidate the three 32-bit system call entry points so that they all
treat registers in similar ways.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>
Signed-off-by: Andi Kleen <ak@xxxxxxx>

arch/x86_64/ia32/ia32entry.S | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

Index: linux/arch/x86_64/ia32/ia32entry.S
===================================================================
--- linux.orig/arch/x86_64/ia32/ia32entry.S
+++ linux/arch/x86_64/ia32/ia32entry.S
@@ -104,7 +104,7 @@ ENTRY(ia32_sysenter_target)
pushq %rax
CFI_ADJUST_CFA_OFFSET 8
cld
- SAVE_ARGS 0,0,0
+ SAVE_ARGS 0,0,1
/* no need to do an access_ok check here because rbp has been
32bit zero extended */ 1: movl (%rbp),%r9d
@@ -294,7 +294,7 @@ ia32_badarg:
*/
ENTRY(ia32_syscall)
- CFI_STARTPROC simple
+ CFI_STARTPROC32 simple
CFI_SIGNAL_FRAME
CFI_DEF_CFA rsp,SS+8-RIP
/*CFI_REL_OFFSET ss,SS-RIP*/
@@ -330,6 +330,7 @@ ia32_sysret:
ia32_tracesys: SAVE_REST
+ CLEAR_RREGS
movq $-ENOSYS,RAX(%rsp) /* really needed? */
movq %rsp,%rdi /* &pt_regs -> arg1 */
call syscall_trace_enter

More comments and/or a less vague patch description would be nice.

What registers? What behavior is being made common? Why?

Jeff


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