/* Copyright (C) 1996, 1997, 1998, 2000 Free Software Foundation, Inc. This file is part of the GNU C Library. Written by Andreas Schwab, , December 1995. 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 #include /* For Linux we can use the system call table in the header file /usr/include/asm/unistd.h of the kernel. But these symbols do not follow the SYS_* syntax so we have to redefine the `SYS_ify' macro here. */ #undef SYS_ify #ifdef __STDC__ # define SYS_ify(syscall_name) __NR_##syscall_name #else # define SYS_ify(syscall_name) __NR_/**/syscall_name #endif #ifdef __ASSEMBLER__ /* Linux uses a negative return value to indicate syscall errors, unlike most Unices, which use the condition codes' carry flag. Since version 2.1 the return value of a system call might be negative even if the call succeeded. E.g., the `lseek' system call might return a large offset. Therefore we must not anymore test for < 0, but test for a real error by making sure the value in %d0 is a real error number. Linus said he will make sure the no syscall returns a value in -1 .. -4095 as a valid result so we can savely test with -4095. */ /* We don't want the label for the error handler to be visible in the symbol table when we define it here. */ #ifdef PIC #define SYSCALL_ERROR_LABEL .Lsyscall_error #else #define SYSCALL_ERROR_LABEL __syscall_error #endif #undef PSEUDO #define PSEUDO(name, syscall_name, args) \ .text; \ ENTRY (name) \ DO_CALL (syscall_name, args); \ cmp.l &-4095, %d0; \ jcc SYSCALL_ERROR_LABEL #undef PSEUDO_END #define PSEUDO_END(name) \ SYSCALL_ERROR_HANDLER; \ END (name) #ifdef PIC /* Store (- %d0) into errno through the GOT. */ #ifdef _LIBC_REENTRANT #define SYSCALL_ERROR_HANDLER \ SYSCALL_ERROR_LABEL: \ neg.l %d0; \ move.l %d0, -(%sp); \ jbsr __errno_location@PLTPC; \ move.l (%sp)+, (%a0); \ move.l &-1, %d0; \ /* Copy return value to %a0 for syscalls that are declared to return \ a pointer (e.g., mmap). */ \ move.l %d0, %a0; \ rts; #else /* !_LIBC_REENTRANT */ #define SYSCALL_ERROR_HANDLER \ SYSCALL_ERROR_LABEL: \ move.l (errno@GOTPC, %pc), %a0; \ neg.l %d0; \ move.l %d0, (%a0); \ move.l &-1, %d0; \ /* Copy return value to %a0 for syscalls that are declared to return \ a pointer (e.g., mmap). */ \ move.l %d0, %a0; \ rts; #endif /* _LIBC_REENTRANT */ #else #define SYSCALL_ERROR_HANDLER /* Nothing here; code in sysdep.S is used. */ #endif /* PIC */ /* Linux takes system call arguments in registers: syscall number %d0 call-clobbered arg 1 %d1 call-clobbered arg 2 %d2 call-saved arg 3 %d3 call-saved arg 4 %d4 call-saved arg 5 %d5 call-saved The stack layout upon entering the function is: 20(%sp) Arg# 5 16(%sp) Arg# 4 12(%sp) Arg# 3 8(%sp) Arg# 2 4(%sp) Arg# 1 (%sp) Return address (Of course a function with say 3 arguments does not have entries for arguments 4 and 5.) Separate move's are faster than movem, but need more space. Since speed is more important, we don't use movem. Since %a0 and %a1 are scratch registers, we can use them for saving as well. */ #define DO_CALL(syscall_name, args) \ move.l &SYS_ify(syscall_name), %d0; \ DOARGS_##args \ trap &0; \ UNDOARGS_##args #define DOARGS_0 /* No arguments to frob. */ #define UNDOARGS_0 /* No arguments to unfrob. */ #define _DOARGS_0(n) /* No arguments to frob. */ #define DOARGS_1 _DOARGS_1 (4) #define _DOARGS_1(n) move.l n(%sp), %d1; _DOARGS_0 (n) #define UNDOARGS_1 UNDOARGS_0 #define DOARGS_2 _DOARGS_2 (8) #define _DOARGS_2(n) move.l %d2, %a0; move.l n(%sp), %d2; _DOARGS_1 (n-4) #define UNDOARGS_2 UNDOARGS_1; move.l %a0, %d2 #define DOARGS_3 _DOARGS_3 (12) #define _DOARGS_3(n) move.l %d3, %a1; move.l n(%sp), %d3; _DOARGS_2 (n-4) #define UNDOARGS_3 UNDOARGS_2; move.l %a1, %d3 #define DOARGS_4 _DOARGS_4 (16) #define _DOARGS_4(n) move.l %d4, -(%sp); move.l n+4(%sp), %d4; _DOARGS_3 (n) #define UNDOARGS_4 UNDOARGS_3; move.l (%sp)+, %d4 #define DOARGS_5 _DOARGS_5 (20) #define _DOARGS_5(n) move.l %d5, -(%sp); move.l n+4(%sp), %d5; _DOARGS_4 (n) #define UNDOARGS_5 UNDOARGS_4; move.l (%sp)+, %d5 #define ret rts #if 0 /* Not used by Linux */ #define r0 %d0 #define r1 %d1 #define MOVE(x,y) movel x , y #endif #else /* not __ASSEMBLER__ */ /* Define a macro which expands into the inline wrapper code for a system call. */ #undef INLINE_SYSCALL #define INLINE_SYSCALL(name, nr, args...) \ ({ unsigned int _sys_result; \ { \ LOAD_ARGS_##nr (args) \ register int _d0 asm ("%d0") = __NR_##name; \ asm volatile ("trap #0" \ : "=d" (_d0) \ : "0" (_d0) ASM_ARGS_##nr \ : "memory"); \ _sys_result = _d0; \ } \ if (_sys_result >= (unsigned int) -4095) \ { \ __set_errno (-_sys_result); \ _sys_result = (unsigned int) -1; \ } \ (int) _sys_result; }) #define LOAD_ARGS_0() #define ASM_ARGS_0 #define LOAD_ARGS_1(a1) \ register int _d1 asm ("d1") = (int) (a1); \ LOAD_ARGS_0 () #define ASM_ARGS_1 ASM_ARGS_0, "d" (_d1) #define LOAD_ARGS_2(a1, a2) \ register int _d2 asm ("d2") = (int) (a2); \ LOAD_ARGS_1 (a1) #define ASM_ARGS_2 ASM_ARGS_1, "d" (_d2) #define LOAD_ARGS_3(a1, a2, a3) \ register int _d3 asm ("d3") = (int) (a3); \ LOAD_ARGS_2 (a1, a2) #define ASM_ARGS_3 ASM_ARGS_2, "d" (_d3) #define LOAD_ARGS_4(a1, a2, a3, a4) \ register int _d4 asm ("d4") = (int) (a4); \ LOAD_ARGS_3 (a1, a2, a3) #define ASM_ARGS_4 ASM_ARGS_3, "d" (_d4) #define LOAD_ARGS_5(a1, a2, a3, a4, a5) \ register int _d5 asm ("d5") = (int) (a5); \ LOAD_ARGS_4 (a1, a2, a3, a4) #define ASM_ARGS_5 ASM_ARGS_4, "d" (_d5) #define LOAD_ARGS_6(a1, a2, a3, a4, a5, a6) \ register int _a0 asm ("a0") = (int) (a6); \ LOAD_ARGS_5 (a1, a2, a3, a4, a5) #define ASM_ARGS_6 ASM_ARGS_5, "a" (_a0) #endif /* not __ASSEMBLER__ */