Add support for people calling syscall()

 -Erik

diff --git a/libc/sysdeps/linux/i386/Makefile b/libc/sysdeps/linux/i386/Makefile
index c15751ee12ee001c9da5e7f2ee231abb1ef874e3..28c64991e7b5e4d48aa8a2bb897500de73f9e27d 100644 (file)
--- a/libc/sysdeps/linux/i386/Makefile
+++ b/libc/sysdeps/linux/i386/Makefile
@@ -36,10 +36,8 @@ CRT0_OBJ=$(patsubst %.S,%.o, $(CRT0))
 endif
 
 
-SSRC=__longjmp.S vfork.S clone.S setjmp.S bsd-setjmp.S bsd-_setjmp.S
-ifeq ($(UNIFIED_SYSCALL),true)
-       SSRC += __uClibc_syscall.S
-endif
+SSRC=__longjmp.S vfork.S clone.S setjmp.S bsd-setjmp.S \
+       bsd-_setjmp.S syscall.S
 SOBJS=$(patsubst %.S,%.o, $(SSRC))
 
 CSRC=brk.c

diff --git a/libc/sysdeps/linux/i386/__uClibc_syscall.S b/libc/sysdeps/linux/i386/__uClibc_syscall.S
deleted file mode 100644 (file)
index b79d266..0000000
--- a/libc/sysdeps/linux/i386/__uClibc_syscall.S
+++ /dev/null
@@ -1,72 +0,0 @@
-/*
- * June 27, 2001             Manuel Novoa III
- *
- * This is a heavily modified version of gcc's output for the syscall5 macro.
- * The idea (originally from dietlibc) is that all syscall functions simply
- * set the syscall number in %al (since <= 255) and then jump here.  All the
- * common work is done by __uClibc_syscall, saving a fair amount of generated
- * code where a number of syscalls are used.  The (potential) cost is some 
- * unnecessary pushes, pops, and movs but the execution time penalty should
- * be relatively small compared to the cost of the syscall itself.
- *
- * WARNING: If the startup code for uClibc changes, I suppose it is possible
- *          that this code might try to access memory under the bottom of
- *          the stack.
- * WARNING: This will need to be modified if the number of syscalls ever
- *          exceeds 255.  So will the associated syscall macros.
- */
-       
-.text
-       .align 4
-.globl __uClibc_syscall
-       .type    __uClibc_syscall,@function
-__uClibc_syscall:
-       pushl %edi
-       pushl %esi
-       pushl %ebx
-       and $0xff,%eax
-       movl 16(%esp),%ebx
-       movl 20(%esp),%ecx
-       movl 24(%esp),%edx
-       movl 28(%esp),%esi
-       movl 32(%esp),%edi
-#APP
-       int $0x80
-#NO_APP
-       cmpl $-4095,%eax
-       jbe .Ldone
-
-#ifdef PIC
-       call Lhere
-Lhere:
-       popl %ebx
-       addl $_GLOBAL_OFFSET_TABLE_+[.-Lhere],%ebx
-       negl %eax
-       movl %eax,%ecx
-#ifdef _LIBC_REENTRANT
-       call __errno_location@PLT
-#else
-       movl errno@GOT(%ebx),%eax
-#endif /* _LIBC_REENTRANT */
-       movl %ecx,(%eax)
-#else
-       negl %eax
-#ifdef _LIBC_REENTRANT
-       movl %eax,%ecx
-       call __errno_location
-       movl %ecx,(%eax)
-#else
-       movl %eax,errno
-#endif /* _LIBC_REENTRANT */
-
-#endif /* PIC */
-
-       movl $-1,%eax
-       .p2align 4,,7
-.Ldone:
-       popl %ebx
-       popl %esi
-       popl %edi
-       ret
-.Lsize:
-       .size    __uClibc_syscall,.Lsize-__uClibc_syscall

diff --git a/libc/sysdeps/linux/i386/syscall.S b/libc/sysdeps/linux/i386/syscall.S
new file mode 100644 (file)
index 0000000..c67b39e
--- /dev/null
+++ b/libc/sysdeps/linux/i386/syscall.S
@@ -0,0 +1,76 @@
+/*
+ * June 27, 2001             Manuel Novoa III
+ *
+ * This is a heavily modified version of gcc's output for the _syscall5 macro.
+ * The idea (originally from dietlibc) is that all syscall functions simply set
+ * the syscall number as the first argument, then set the syscall arguments as
+ * the next up-to-five arguments, and then jump here.  All the common work is
+ * done by syscall(), saving a fair amount of generated code when a number of
+ * syscalls are used.  The (potential) cost is some unnecessary pushes, pops,
+ * and movs but the execution time penalty should be relatively small compared
+ * to the cost of the syscall itself.
+ *
+ * July 24, 2002 
+ *
+ * Modified by Erik Andersen to take all function parameters from off the stack
+ * like a proper function and eliminates the old 255 syscall number limit.  So
+ * now we can just call this as a function as syscall() per the function
+ * prototype in unistd.h, so to call _exit(42) you can just call.
+ *         syscall(__NR_exit, 42);
+ * and things will just work.
+ */
+       
+.text
+       .align 4
+.globl syscall
+       .type    syscall,@function
+syscall:
+       pushl %edi
+       pushl %esi
+       pushl %ebx
+       movl  36(%esp),%edi;    /* Load the 5 syscall argument registers */
+       movl  32(%esp),%esi;
+       movl  28(%esp),%edx;
+       movl  24(%esp),%ecx;
+       movl  20(%esp),%ebx;
+       movl  16(%esp),%eax     /* Load syscall number into %eax.  */
+#APP
+       int $0x80
+#NO_APP
+       cmpl $-4095,%eax
+       jbe .Ldone
+
+#ifdef PIC
+       call Lhere
+Lhere:
+       popl %ebx
+       addl $_GLOBAL_OFFSET_TABLE_+[.-Lhere],%ebx
+       negl %eax
+       movl %eax,%ecx
+#ifdef _LIBC_REENTRANT
+       call __errno_location@PLT
+#else
+       movl errno@GOT(%ebx),%eax
+#endif /* _LIBC_REENTRANT */
+       movl %ecx,(%eax)
+#else
+       negl %eax
+#ifdef _LIBC_REENTRANT
+       movl %eax,%ecx
+       call __errno_location
+       movl %ecx,(%eax)
+#else
+       movl %eax,errno
+#endif /* _LIBC_REENTRANT */
+
+#endif /* PIC */
+
+       movl $-1,%eax
+       .p2align 4,,7
+.Ldone:
+       popl %ebx
+       popl %esi
+       popl %edi
+       ret
+.Lsize:
+       .size    syscall,.Lsize-syscall