diff options
| -rw-r--r-- | libc/sysdeps/linux/alpha/Makefile.arch | 4 | ||||
| -rw-r--r-- | libc/sysdeps/linux/alpha/syscall.S | 71 |
2 files changed, 73 insertions, 2 deletions
diff --git a/libc/sysdeps/linux/alpha/Makefile.arch b/libc/sysdeps/linux/alpha/Makefile.arch index 91636c71a..4d33cef26 100644 --- a/libc/sysdeps/linux/alpha/Makefile.arch +++ b/libc/sysdeps/linux/alpha/Makefile.arch @@ -5,10 +5,10 @@ # Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball. # -CSRC := sysdep.c #brk.c +CSRC := sysdep.c SSRC := \ __longjmp.S brk.S bsd-_setjmp.S bsd-setjmp.S clone.S \ - divl.S divq.S reml.S remq.S setjmp.S + divl.S divq.S reml.S remq.S setjmp.S syscall.S include $(top_srcdir)libc/sysdeps/linux/Makefile.commonarch diff --git a/libc/sysdeps/linux/alpha/syscall.S b/libc/sysdeps/linux/alpha/syscall.S new file mode 100644 index 000000000..1ccb5815f --- /dev/null +++ b/libc/sysdeps/linux/alpha/syscall.S @@ -0,0 +1,71 @@ +/* Copyright (C) 1996 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by David Mosberger <davidm@azstarnet.com>, 1996. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#include <features.h> +#include <asm/regdef.h> +#include <asm/pal.h> + +/* + * This is for COMPATIBILITY with Linux/x86 only. Linux/Alpha system + * calls return an error indication in a3. This allows arbitrary 64bit + * values to be returned in v0 (because negative values are not + * mistaken as error numbers). However, C allows only one value to + * be returned, so the interface below folds the error indication passed in + * a3 back into v0: it sets v0 to -errno if an error occurs. Thus, + * no negative 64bit numbers can be returned. To avoid this problem, + * use assembly stubs wherever possible/convenient. + * + * Usage: + * + * long syscall(syscall_number, arg1, arg2, arg3, arg4, arg5) + * + * syscall_number = the index of the system call we're invoking + * arg1-arg5 = up to 5 integer arguments to the system call + * + * We need to do some arg shifting: the kernel expects the + * syscall number in v0 and the first five args in a0-a4. + * + */ + +.globl __syscall; +.align 4; +.ent __syscall, 0; +__syscall: +.frame sp, 0, ra + .prologue 0 + + mov a0, v0 /* Syscall number -> v0 */ + mov a1, a0 /* arg1-arg5 -> a0-a4 */ + mov a2, a1 + mov a3, a2 + mov a4, a3 + mov a5, a4 + + call_pal PAL_callsys /* Invoke system call */ + bne a3, $error + ret + +$error: + br gp, 2f +2: ldgp gp, 0(gp) + jmp zero,__syscall_error + +.end __syscall + +weak_alias (__syscall, syscall) |