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authorRich Felker <dalias@aerifal.cx>2012-10-11 22:47:07 -0400
committerRich Felker <dalias@aerifal.cx>2012-10-11 22:47:07 -0400
commit12e9b4faf68a1a02ebf5ad69c03ac10f170f14cb (patch)
treef206db332e670791be0120cb21cc5eee9bc23574 /src
parentf2b1f1af83e96f8f98fbf2a5c663d8d058f2a66d (diff)
downloadmusl-12e9b4faf68a1a02ebf5ad69c03ac10f170f14cb.tar.gz
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.
Diffstat (limited to 'src')
-rw-r--r--src/env/__libc_start_main.c3
-rw-r--r--src/internal/i386/syscall.s74
-rw-r--r--src/internal/libc.c1
3 files changed, 62 insertions, 16 deletions
diff --git a/src/env/__libc_start_main.c b/src/env/__libc_start_main.c
index e350fdb8..ee10b0de 100644
--- a/src/env/__libc_start_main.c
+++ b/src/env/__libc_start_main.c
@@ -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);
diff --git a/src/internal/i386/syscall.s b/src/internal/i386/syscall.s
index 327d4cc0..79296ba0 100644
--- a/src/internal/i386/syscall.s
+++ b/src/internal/i386/syscall.s
@@ -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
diff --git a/src/internal/libc.c b/src/internal/libc.c
index 004c1a33..d22d2747 100644
--- a/src/internal/libc.c
+++ b/src/internal/libc.c
@@ -15,3 +15,4 @@ __asm__(".hidden __libc");
#endif
size_t __hwcap;
+size_t __sysinfo;