This addresses several points:
- CLEAR_RREGS' clearing of R9 became redundant with the recent change
to cstar_tracesys' saving/restoring %r9
- LOAD_ARGS32 has no need for re-loading %r8-%r11, except in the case
of cstar_tracesys, where %r9 must be re-loaded
- the recent change to sysenter handling aimed for full compatibility
with native i386 code, but didn't go as far as making the code match
that behavior even for the non-traced case (i386 loads %ebp from
(%ebp) in all cases)
- that same recent patch failed to recognize the possibility to
eliminate the re-loading for %r8d in cstar_tracesys
Signed-off-by: Jan Beulich <[email protected]>
Cc: Chuck Ebbert <[email protected]>
arch/x86/ia32/ia32entry.S | 24 +++++++++---------------
1 file changed, 9 insertions(+), 15 deletions(-)
--- linux-2.6.24-rc5/arch/x86/ia32/ia32entry.S 2007-12-12 16:48:17.000000000 +0100
+++ 2.6.24-rc5-x86_64-ia32entry/arch/x86/ia32/ia32entry.S 2007-12-07 14:41:50.000000000 +0100
@@ -30,19 +30,18 @@
.endm
/* clobbers %eax */
- .macro CLEAR_RREGS
+ .macro CLEAR_RREGS _r9=rax
xorl %eax,%eax
movq %rax,R11(%rsp)
movq %rax,R10(%rsp)
- movq %rax,R9(%rsp)
+ movq %\_r9,R9(%rsp)
movq %rax,R8(%rsp)
.endm
- .macro LOAD_ARGS32 offset
- movl \offset(%rsp),%r11d
- movl \offset+8(%rsp),%r10d
+ .macro LOAD_ARGS32 offset, _r9=0
+ .if \_r9
movl \offset+16(%rsp),%r9d
- movl \offset+24(%rsp),%r8d
+ .endif
movl \offset+40(%rsp),%ecx
movl \offset+48(%rsp),%edx
movl \offset+56(%rsp),%esi
@@ -119,7 +118,7 @@ ENTRY(ia32_sysenter_target)
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
+1: movl (%rbp),%ebp
.section __ex_table,"a"
.quad 1b,ia32_badarg
.previous
@@ -131,7 +130,7 @@ ENTRY(ia32_sysenter_target)
sysenter_do_call:
cmpl $(IA32_NR_syscalls-1),%eax
ja ia32_badsys
- IA32_ARG_FIXUP 1
+ IA32_ARG_FIXUP
call *ia32_sys_call_table(,%rax,8)
movq %rax,RAX-ARGOFFSET(%rsp)
GET_THREAD_INFO(%r10)
@@ -159,16 +158,13 @@ sysenter_do_call:
sysenter_tracesys:
CFI_RESTORE_STATE
- xchgl %r9d,%ebp
SAVE_REST
CLEAR_RREGS
- movq %r9,R9(%rsp)
movq $-ENOSYS,RAX(%rsp) /* really needed? */
movq %rsp,%rdi /* &pt_regs -> arg1 */
call syscall_trace_enter
LOAD_ARGS32 ARGOFFSET /* reload args from stack in case ptrace changed it */
RESTORE_REST
- xchgl %ebp,%r9d
jmp sysenter_do_call
CFI_ENDPROC
ENDPROC(ia32_sysenter_target)
@@ -260,15 +256,13 @@ cstar_tracesys:
CFI_RESTORE_STATE
xchgl %r9d,%ebp
SAVE_REST
- CLEAR_RREGS
- movq %r9,R9(%rsp)
+ CLEAR_RREGS r9
movq $-ENOSYS,RAX(%rsp) /* really needed? */
movq %rsp,%rdi /* &pt_regs -> arg1 */
call syscall_trace_enter
- LOAD_ARGS32 ARGOFFSET /* reload args from stack in case ptrace changed it */
+ LOAD_ARGS32 ARGOFFSET, 1 /* reload args from stack in case ptrace changed it */
RESTORE_REST
xchgl %ebp,%r9d
- movl RSP-ARGOFFSET(%rsp), %r8d
jmp cstar_do_call
END(ia32_cstar_target)
--
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