i386 vsyscall support (vdso-provided sysenter/syscall instruction based)

this doubles the performance of the fastest syscalls on the atom I
tested it on; improvement is reportedly much more dramatic on
worst-case cpus. cannot be used for cancellable syscalls.
This commit is contained in:
Rich Felker 2012-10-11 22:47:07 -04:00
parent f2b1f1af83
commit 12e9b4faf6
4 changed files with 69 additions and 82 deletions

View File

@ -8,111 +8,52 @@
static inline long __syscall0(long n)
{
unsigned long __ret;
__asm__ __volatile__ ("int $128" : "=a"(__ret) : "a"(n) : "memory");
__asm__ __volatile__ ("call __vsyscall" : "=a"(__ret) : "a"(n) : "memory");
return __ret;
}
#ifndef __PIC__
static inline long __syscall1(long n, long a1)
{
unsigned long __ret;
__asm__ __volatile__ ("int $128" : "=a"(__ret) : "a"(n), "b"(a1) : "memory");
__asm__ __volatile__ ("call __vsyscall" : "=a"(__ret) : "a"(n), "d"(a1) : "memory");
return __ret;
}
static inline long __syscall2(long n, long a1, long a2)
{
unsigned long __ret;
__asm__ __volatile__ ("int $128" : "=a"(__ret) : "a"(n), "b"(a1), "c"(a2) : "memory");
__asm__ __volatile__ ("call __vsyscall" : "=a"(__ret) : "a"(n), "d"(a1), "c"(a2) : "memory");
return __ret;
}
static inline long __syscall3(long n, long a1, long a2, long a3)
{
unsigned long __ret;
__asm__ __volatile__ ("int $128" : "=a"(__ret) : "a"(n), "b"(a1), "c"(a2), "d"(a3) : "memory");
__asm__ __volatile__ ("call __vsyscall" : "=a"(__ret) : "a"(n), "d"(a1), "c"(a2), "D"(a3) : "memory");
return __ret;
}
static inline long __syscall4(long n, long a1, long a2, long a3, long a4)
{
unsigned long __ret;
__asm__ __volatile__ ("int $128" : "=a"(__ret) : "a"(n), "b"(a1), "c"(a2), "d"(a3), "S"(a4) : "memory");
__asm__ __volatile__ ("call __vsyscall" : "=a"(__ret) : "a"(n), "d"(a1), "c"(a2), "D"(a3), "S"(a4) : "memory");
return __ret;
}
static inline long __syscall5(long n, long a1, long a2, long a3, long a4, long a5)
{
unsigned long __ret;
__asm__ __volatile__ ("int $128" : "=a"(__ret) : "a"(n), "b"(a1), "c"(a2), "d"(a3), "S"(a4), "D"(a5) : "memory");
__asm__ __volatile__ ("push %6 ; call __vsyscall ; add $4,%%esp" : "=a"(__ret) : "a"(n), "d"(a1), "c"(a2), "D"(a3), "S"(a4), "g"(a5) : "memory");
return __ret;
}
static inline long __syscall6(long n, long a1, long a2, long a3, long a4, long a5, long a6)
{
unsigned long __ret;
__asm__ __volatile__ ("pushl %7 ; pushl %%ebp ; mov 4(%%esp),%%ebp ; int $128 ; popl %%ebp ; popl %%ecx"
: "=a"(__ret) : "a"(n), "b"(a1), "c"(a2), "d"(a3), "S"(a4), "D"(a5), "g"(a6) : "memory");
__asm__ __volatile__ ("push %6 ; call __vsyscall6 ; add $4,%%esp" : "=a"(__ret) : "a"(n), "d"(a1), "c"(a2), "D"(a3), "S"(a4), "g"((long[]){a5, a6}) : "memory");
return __ret;
}
#else
static inline long __syscall1(long n, long a1)
{
unsigned long __ret;
__asm__ __volatile__ ("xchg %2,%%ebx ; int $128 ; xchg %2,%%ebx"
: "=a"(__ret) : "a"(n), "d"(a1) : "memory");
return __ret;
}
static inline long __syscall2(long n, long a1, long a2)
{
unsigned long __ret;
__asm__ __volatile__ ("xchg %2,%%ebx ; int $128 ; xchg %2,%%ebx"
: "=a"(__ret) : "a"(n), "d"(a1), "c"(a2) : "memory");
return __ret;
}
static inline long __syscall3(long n, long a1, long a2, long a3)
{
unsigned long __ret;
__asm__ __volatile__ ("xchg %2,%%ebx ; int $128 ; xchg %2,%%ebx"
: "=a"(__ret) : "a"(n), "S"(a1), "c"(a2), "d"(a3) : "memory");
return __ret;
}
static inline long __syscall4(long n, long a1, long a2, long a3, long a4)
{
unsigned long __ret;
__asm__ __volatile__ ("xchg %2,%%ebx ; int $128 ; xchg %2,%%ebx"
: "=a"(__ret) : "a"(n), "D"(a1), "c"(a2), "d"(a3), "S"(a4) : "memory");
return __ret;
}
#if 0
static inline long __syscall5(long n, long a1, long a2, long a3, long a4, long a5)
{
unsigned long __ret;
__asm__ __volatile__ ("pushl %2 ; pushl %%ebx ; mov 4(%%esp),%%ebx ; int $128 ; popl %%ebx ; popl %%ecx"
: "=a"(__ret) : "a"(n), "g"(a1), "c"(a2), "d"(a3), "S"(a4), "D"(a5) : "memory");
return __ret;
}
#else
static inline long __syscall5(long n, long a1, long a2, long a3, long a4, long a5)
{
return (__syscall)(n, a1, a2, a3, a4, a5);
}
#endif
static inline long __syscall6(long n, long a1, long a2, long a3, long a4, long a5, long a6)
{
return (__syscall)(n, a1, a2, a3, a4, a5, a6);
}
#endif
#define __SC_socket 1
#define __SC_bind 2

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@ -6,6 +6,8 @@ void __init_security(size_t *);
#define AUX_CNT 38
extern size_t __hwcap, __sysinfo;
void __init_libc(char **envp)
{
size_t i, *auxv, aux[AUX_CNT] = { 0 };
@ -14,6 +16,7 @@ void __init_libc(char **envp)
libc.auxv = auxv = (void *)(envp+i+1);
for (i=0; auxv[i]; i+=2) if (auxv[i]<AUX_CNT) aux[auxv[i]] = auxv[i+1];
__hwcap = aux[AT_HWCAP];
__sysinfo = aux[AT_SYSINFO];
__init_tls(aux);
__init_security(aux);

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@ -1,20 +1,62 @@
.hidden __sysinfo
.global __vsyscall
.type __vsyscall,@function
__vsyscall:
push %edi
push %ebx
mov %edx,%ebx
mov %edi,%edx
mov 12(%esp),%edi
push %eax
call 1f
2: pop %ebx
pop %ebx
pop %edi
ret
1: mov (%esp),%eax
add $[__sysinfo-2b],%eax
mov (%eax),%eax
test %eax,%eax
jz 1f
push %eax
mov 8(%esp),%eax
ret
1: mov 4(%esp),%eax
int $128
ret
.global __vsyscall6
.type __vsyscall6,@function
__vsyscall6:
push %ebp
push %eax
mov 12(%esp), %ebp
mov (%ebp), %eax
mov 4(%ebp), %ebp
push %eax
mov 4(%esp),%eax
call __vsyscall
pop %ebp
pop %ebp
pop %ebp
ret
.global __syscall
.type __syscall,@function
__syscall:
pushl %ebx
pushl %esi
pushl %edi
pushl %ebp
movl 20(%esp),%eax
movl 24(%esp),%ebx
movl 28(%esp),%ecx
movl 32(%esp),%edx
movl 36(%esp),%esi
movl 40(%esp),%edi
movl 44(%esp),%ebp
int $128
popl %ebp
popl %edi
popl %esi
popl %ebx
lea 24(%esp),%eax
push %esi
push %edi
push %eax
mov 16(%esp),%eax
mov 20(%esp),%edx
mov 24(%esp),%ecx
mov 28(%esp),%edi
mov 32(%esp),%esi
call __vsyscall6
pop %edi
pop %edi
pop %esi
ret

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@ -15,3 +15,4 @@ __asm__(".hidden __libc");
#endif
size_t __hwcap;
size_t __sysinfo;