summaryrefslogtreecommitdiff
path: root/src
diff options
context:
space:
mode:
authorRich Felker <dalias@aerifal.cx>2011-03-19 18:51:42 -0400
committerRich Felker <dalias@aerifal.cx>2011-03-19 18:51:42 -0400
commitd00ff2950eacc375d57e44d65c7697f636c67625 (patch)
tree33949c7eb7e75251b3a598f964db558604caf7c6 /src
parent56fd65e861e0ad0ea7677211f8258a8f64233f26 (diff)
downloadmusl-d00ff2950eacc375d57e44d65c7697f636c67625.tar.gz
overhaul syscall interface
this commit shuffles around the location of syscall definitions so that we can make a syscall() library function with both SYS_* and __NR_* style syscall names available to user applications, provides the syscall() library function, and optimizes the code that performs the actual inline syscalls in the library itself. previously on i386 when built as PIC (shared library), syscalls were incurring bus lock (lock prefix) overhead at entry and exit, due to the way the ebx register was being loaded (xchg instruction with a memory operand). now the xchg takes place between two registers. further cleanup to arch/$(ARCH)/syscall.h is planned.
Diffstat (limited to 'src')
-rw-r--r--src/internal/i386/syscall.s21
-rw-r--r--src/internal/syscall.c11
-rw-r--r--src/internal/syscall_ret.c11
-rw-r--r--src/internal/x86_64/syscall.s14
-rw-r--r--src/linux/syscall.c19
-rw-r--r--src/thread/pthread_create.c4
6 files changed, 67 insertions, 13 deletions
diff --git a/src/internal/i386/syscall.s b/src/internal/i386/syscall.s
new file mode 100644
index 00000000..5b19a1b8
--- /dev/null
+++ b/src/internal/i386/syscall.s
@@ -0,0 +1,21 @@
+.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
+ ret
+.size __syscall,.-__syscall
diff --git a/src/internal/syscall.c b/src/internal/syscall.c
index 4f159e0b..e69de29b 100644
--- a/src/internal/syscall.c
+++ b/src/internal/syscall.c
@@ -1,11 +0,0 @@
-#include <errno.h>
-#include <unistd.h>
-
-long __syscall_ret(unsigned long r)
-{
- if (r >= (unsigned long)-1 - 4096) {
- errno = -(long)r;
- return -1;
- }
- return (long)r;
-}
diff --git a/src/internal/syscall_ret.c b/src/internal/syscall_ret.c
new file mode 100644
index 00000000..4f159e0b
--- /dev/null
+++ b/src/internal/syscall_ret.c
@@ -0,0 +1,11 @@
+#include <errno.h>
+#include <unistd.h>
+
+long __syscall_ret(unsigned long r)
+{
+ if (r >= (unsigned long)-1 - 4096) {
+ errno = -(long)r;
+ return -1;
+ }
+ return (long)r;
+}
diff --git a/src/internal/x86_64/syscall.s b/src/internal/x86_64/syscall.s
new file mode 100644
index 00000000..7bec7291
--- /dev/null
+++ b/src/internal/x86_64/syscall.s
@@ -0,0 +1,14 @@
+.global __syscall
+.type __syscall,%function
+__syscall:
+di,si,dx,cx,r8,r9
+ movq %rdi,%rax
+ movq %rsi,%rdi
+ movq %rdx,%rsi
+ movq %rcx,%rdx
+ movq %r8,%r10
+ movq %r9,%r8
+ movq 8(%rsp),%r9
+ syscall
+ ret
+.size __syscall,.-__syscall
diff --git a/src/linux/syscall.c b/src/linux/syscall.c
new file mode 100644
index 00000000..15355609
--- /dev/null
+++ b/src/linux/syscall.c
@@ -0,0 +1,19 @@
+#include "syscall.h"
+#include <stdarg.h>
+
+#undef syscall
+
+long syscall(long n, ...)
+{
+ va_list ap;
+ long a,b,c,d,e,f;
+ va_start(ap, n);
+ a=va_arg(ap, long);
+ b=va_arg(ap, long);
+ c=va_arg(ap, long);
+ d=va_arg(ap, long);
+ e=va_arg(ap, long);
+ f=va_arg(ap, long);
+ va_end(ap);
+ return __syscall_ret(__syscall(n,a,b,c,d,e,f));
+}
diff --git a/src/thread/pthread_create.c b/src/thread/pthread_create.c
index 7494a486..fccfa191 100644
--- a/src/thread/pthread_create.c
+++ b/src/thread/pthread_create.c
@@ -91,7 +91,7 @@ static void rsyscall_handler(int sig, siginfo_t *si, void *ctx)
return;
}
- if (syscall6(rs.nr, rs.arg[0], rs.arg[1], rs.arg[2],
+ if (__syscall(rs.nr, rs.arg[0], rs.arg[1], rs.arg[2],
rs.arg[3], rs.arg[4], rs.arg[5]) < 0 && !rs.err) rs.err=errno;
a_inc(&rs.cnt);
@@ -140,7 +140,7 @@ static int rsyscall(int nr, long a, long b, long c, long d, long e, long f)
while((i=rs.cnt)) __wait(&rs.cnt, 0, i, 1);
if (rs.err) errno = rs.err, ret = -1;
- else ret = syscall6(nr, a, b, c, d, e, f);
+ else ret = __syscall(nr, a, b, c, d, e, f);
UNLOCK(&rs.lock);
return ret;