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Change the syscall stub branch orders so that the static branch prediction

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will assume that syscalls will succeed rather than fail.
This commit is contained in:
peter 2004-02-22 02:11:39 +00:00
parent ce2cfa1a8b
commit 025be3a06b
4 changed files with 51 additions and 12 deletions
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15
lib/libc/amd64/SYS.h
View File

@ -41,26 +41,23 @@
#include <machine/asm.h>
#ifdef PIC
#define SYSCALL(x) 2: movq PIC_GOT(HIDENAME(cerror)),%rcx; \
jmp *%rcx; \
ENTRY(__CONCAT(__sys_,x)); \
#define RSYSCALL(x) ENTRY(__CONCAT(__sys_,x)); \
.weak CNAME(x); \
.set CNAME(x),CNAME(__CONCAT(__sys_,x)); \
.weak CNAME(__CONCAT(_,x)); \
.set CNAME(__CONCAT(_,x)),CNAME(__CONCAT(__sys_,x)); \
mov __CONCAT($SYS_,x),%rax; KERNCALL; jb 2b
mov __CONCAT($SYS_,x),%rax; KERNCALL; jb 2f; ret; \
2: movq PIC_GOT(HIDENAME(cerror)),%rcx; jmp *%rcx
#else
#define SYSCALL(x) 2: jmp HIDENAME(cerror); \
ENTRY(__CONCAT(__sys_,x)); \
#define RSYSCALL(x) ENTRY(__CONCAT(__sys_,x)); \
.weak CNAME(x); \
.set CNAME(x),CNAME(__CONCAT(__sys_,x)); \
.weak CNAME(__CONCAT(_,x)); \
.set CNAME(__CONCAT(_,x)),CNAME(__CONCAT(__sys_,x)); \
mov __CONCAT($SYS_,x),%rax; KERNCALL; jb 2b
mov __CONCAT($SYS_,x),%rax; KERNCALL; jb 2f; ret; \
2: jmp HIDENAME(cerror)
#endif
#define RSYSCALL(x) SYSCALL(x); ret
#define PSEUDO(x) ENTRY(__CONCAT(__sys_,x)); \
.weak CNAME(__CONCAT(_,x)); \
.set CNAME(__CONCAT(_,x)),CNAME(__CONCAT(__sys_,x)); \

16
lib/libc/amd64/sys/pipe.S
View File

@ -42,8 +42,22 @@ __FBSDID("$FreeBSD$");
#include "SYS.h"
SYSCALL(pipe)
.weak _pipe
.set _pipe,__sys_pipe
.weak pipe
.set pipe,__sys_pipe
ENTRY(__sys_pipe)
mov $SYS_pipe,%rax
KERNCALL
jb 1f
movl %eax,(%rdi) /* %rdi is preserved by syscall */
movl %edx,4(%rdi)
movq $0,%rax
ret
1:
#ifdef PIC
movq PIC_GOT(HIDENAME(cerror)),%rdx
jmp *%rdx
#else
jmp HIDENAME(cerror)
#endif

16
lib/libc/amd64/sys/reboot.S
View File

@ -42,5 +42,19 @@ __FBSDID("$FreeBSD$");
#include "SYS.h"
SYSCALL(reboot)
.weak _reboot
.set _reboot,__sys_reboot
.weak reboot
.set reboot,__sys_reboot
ENTRY(__sys_reboot)
mov $SYS_reboot,%rax
KERNCALL
jb 1f
iretq
1:
#ifdef PIC
movq PIC_GOT(HIDENAME(cerror)),%rdx
jmp *%rdx
#else
jmp HIDENAME(cerror)
#endif

16
lib/libc/amd64/sys/setlogin.S
View File

@ -44,7 +44,14 @@ __FBSDID("$FreeBSD$");
.globl CNAME(_logname_valid) /* in _getlogin() */
SYSCALL(setlogin)
.weak _setlogin
.set _setlogin,__sys_setlogin
.weak setlogin
.set setlogin,__sys_setlogin
ENTRY(__sys_setlogin)
mov $SYS_setlogin,%rax
KERNCALL
jb 1f
#ifdef PIC
movq PIC_GOT(CNAME(_logname_valid)),%rdx
movl $0,(%rdx)
@ -52,3 +59,10 @@ SYSCALL(setlogin)
movl $0,CNAME(_logname_valid)(%rip)
#endif
ret /* setlogin(name) */
1:
#ifdef PIC
movq PIC_GOT(HIDENAME(cerror)),%rdx
jmp *%rdx
#else
jmp HIDENAME(cerror)
#endif