The patch titled
x86-64: slightly streamline 32-bit syscall entry code
has been added to the -mm tree. Its filename is
x86-64-slightly-streamline-32-bit-syscall-entry-code.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: x86-64: slightly streamline 32-bit syscall entry code
From: Jan Beulich <jbeulich@xxxxxxxxxx>
Avoid updating registers or memory twice as well as needlessly loading
or copying registers.
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/x86/ia32/ia32entry.S | 26 ++++++++++----------------
1 file changed, 10 insertions(+), 16 deletions(-)
diff -puN arch/x86/ia32/ia32entry.S~x86-64-slightly-streamline-32-bit-syscall-entry-code arch/x86/ia32/ia32entry.S
--- a/arch/x86/ia32/ia32entry.S~x86-64-slightly-streamline-32-bit-syscall-entry-code
+++ a/arch/x86/ia32/ia32entry.S
@@ -39,11 +39,11 @@
.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
@@ -52,11 +52,10 @@
* We don't reload %eax because syscall_trace_enter() returned
* the value it wants us to use in the table lookup.
*/
- .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
@@ -145,7 +144,7 @@ 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
@@ -157,7 +156,7 @@ ENTRY(ia32_sysenter_target)
cmpl $(IA32_NR_syscalls-1),%eax
ja ia32_badsys
sysenter_do_call:
- IA32_ARG_FIXUP 1
+ IA32_ARG_FIXUP
sysenter_dispatch:
call *ia32_sys_call_table(,%rax,8)
movq %rax,RAX-ARGOFFSET(%rsp)
@@ -234,20 +233,17 @@ sysexit_audit:
#endif
sysenter_tracesys:
- xchgl %r9d,%ebp
#ifdef CONFIG_AUDITSYSCALL
testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags(%r10)
jz sysenter_auditsys
#endif
SAVE_REST
CLEAR_RREGS
- movq %r9,R9(%rsp)
movq $-ENOSYS,RAX(%rsp)/* ptrace can change this for a bad syscall */
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
cmpl $(IA32_NR_syscalls-1),%eax
ja int_ret_from_sys_call /* sysenter_tracesys has set RAX(%rsp) */
jmp sysenter_do_call
@@ -314,9 +310,9 @@ ENTRY(ia32_cstar_target)
testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%r10)
CFI_REMEMBER_STATE
jnz cstar_tracesys
-cstar_do_call:
cmpl $IA32_NR_syscalls-1,%eax
ja ia32_badsys
+cstar_do_call:
IA32_ARG_FIXUP 1
cstar_dispatch:
call *ia32_sys_call_table(,%rax,8)
@@ -357,15 +353,13 @@ cstar_tracesys:
#endif
xchgl %r9d,%ebp
SAVE_REST
- CLEAR_RREGS
- movq %r9,R9(%rsp)
+ CLEAR_RREGS r9
movq $-ENOSYS,RAX(%rsp) /* ptrace can change this for a bad syscall */
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
cmpl $(IA32_NR_syscalls-1),%eax
ja int_ret_from_sys_call /* cstar_tracesys has set RAX(%rsp) */
jmp cstar_do_call
_
Patches currently in -mm which might be from jbeulich@xxxxxxxxxx are
linux-next.patch
x86-init-annotations-in-early_printk-setup.patch
x86-adjust-dependencies-for-config_x86_cmov.patch
x86-pgd_cdtor-cleanup.patch
x86-x86_physvirt_bits-field-also-for-i386.patch
x86-adjust-vmalloc_sync_all-for-xen-2nd-try.patch
x86-fix-ticket-spin-lock-asm-constraints.patch
x86-64-reduce-boot-fixmap-space.patch
x86-64-add-two-__cpuinit-annotations.patch
x86-64-eliminate-dead-code.patch
x86-64-slightly-streamline-32-bit-syscall-entry-code.patch
adjust-init-section-definitions.patch
kconfig-eliminate-def_bool-n-constructs.patch
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