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

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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
commit 12e9b4faf6
4 changed files with 69 additions and 82 deletions
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73
arch/i386/syscall_arch.h
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@ -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