/* Copyright (C) 1992, 93, 1995-2000, 2002, 2003 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Ulrich Drepper, , August 1995. ARM changes by Philip Blundell, , May 1997. 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. */ #ifndef _LINUX_ARM_SYSDEP_H #define _LINUX_ARM_SYSDEP_H 1 /* There is some commonality. */ #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 #define SWI_BASE (0x900000) #define SYS_ify(syscall_name) (__NR_##syscall_name) #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 R0 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. */ #undef PSEUDO #define PSEUDO(name, syscall_name, args) \ .text; \ ENTRY (name); \ DO_CALL (syscall_name, args); \ cmn r0, $4096; #define PSEUDO_RET \ RETINSTR(movcc, pc, lr); \ b PLTJMP(SYSCALL_ERROR) #undef ret #define ret PSEUDO_RET #undef PSEUDO_END #define PSEUDO_END(name) \ SYSCALL_ERROR_HANDLER \ END (name) #if NOT_IN_libc # define SYSCALL_ERROR __local_syscall_error # define SYSCALL_ERROR_HANDLER \ __local_syscall_error: \ str lr, [sp, #-4]!; \ str r0, [sp, #-4]!; \ bl PLTJMP(C_SYMBOL_NAME(__errno_location)); \ ldr r1, [sp], #4; \ rsb r1, r1, #0; \ str r1, [r0]; \ mvn r0, #0; \ ldr pc, [sp], #4; #else # define SYSCALL_ERROR_HANDLER /* Nothing here; code in sysdep.S is used. */ # define SYSCALL_ERROR __syscall_error #endif /* Linux takes system call args in registers: syscall number in the SWI instruction arg 1 r0 arg 2 r1 arg 3 r2 arg 4 r3 arg 5 r4 (this is different from the APCS convention) arg 6 r5 arg 7 r6 The compiler is going to form a call by coming here, through PSEUDO, with arguments syscall number in the DO_CALL macro arg 1 r0 arg 2 r1 arg 3 r2 arg 4 r3 arg 5 [sp] arg 6 [sp+4] arg 7 [sp+8] We need to shuffle values between R4..R6 and the stack so that the caller's v1..v3 and stack frame are not corrupted, and the kernel sees the right arguments. */ #undef DO_CALL #define DO_CALL(syscall_name, args) \ DOARGS_##args \ swi SYS_ify (syscall_name); \ UNDOARGS_##args #define DOARGS_0 /* nothing */ #define DOARGS_1 /* nothing */ #define DOARGS_2 /* nothing */ #define DOARGS_3 /* nothing */ #define DOARGS_4 /* nothing */ #define DOARGS_5 str r4, [sp, $-4]!; ldr r4, [sp, $4]; #define DOARGS_6 mov ip, sp; stmfd sp!, {r4, r5}; ldmia ip, {r4, r5}; #define DOARGS_7 mov ip, sp; stmfd sp!, {r4, r5, r6}; ldmia ip, {r4, r5, r6}; #define UNDOARGS_0 /* nothing */ #define UNDOARGS_1 /* nothing */ #define UNDOARGS_2 /* nothing */ #define UNDOARGS_3 /* nothing */ #define UNDOARGS_4 /* nothing */ #define UNDOARGS_5 ldr r4, [sp], $4; #define UNDOARGS_6 ldmfd sp!, {r4, r5}; #define UNDOARGS_7 ldmfd sp!, {r4, r5, r6}; #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 = INTERNAL_SYSCALL (name, , nr, args); \ if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (_sys_result, ), 0)) \ { \ __set_errno (INTERNAL_SYSCALL_ERRNO (_sys_result, )); \ _sys_result = (unsigned int) -1; \ } \ (int) _sys_result; }) #undef INTERNAL_SYSCALL_DECL #define INTERNAL_SYSCALL_DECL(err) do { } while (0) #undef INTERNAL_SYSCALL #define INTERNAL_SYSCALL(name, err, nr, args...) \ ({ unsigned int _sys_result; \ { \ register int _a1 asm ("a1"); \ LOAD_ARGS_##nr (args) \ asm volatile ("swi %1 @ syscall " #name \ : "=r" (_a1) \ : "i" (SYS_ify(name)) ASM_ARGS_##nr \ : "a1", "memory"); \ _sys_result = _a1; \ } \ (int) _sys_result; }) #undef INTERNAL_SYSCALL_ERROR_P #define INTERNAL_SYSCALL_ERROR_P(val, err) \ ((unsigned int) (val) >= 0xfffff001u) #undef INTERNAL_SYSCALL_ERRNO #define INTERNAL_SYSCALL_ERRNO(val, err) (-(val)) #define LOAD_ARGS_0() #define ASM_ARGS_0 #define LOAD_ARGS_1(a1) \ _a1 = (int) (a1); \ LOAD_ARGS_0 () #define ASM_ARGS_1 ASM_ARGS_0, "r" (_a1) #define LOAD_ARGS_2(a1, a2) \ register int _a2 asm ("a2") = (int) (a2); \ LOAD_ARGS_1 (a1) #define ASM_ARGS_2 ASM_ARGS_1, "r" (_a2) #define LOAD_ARGS_3(a1, a2, a3) \ register int _a3 asm ("a3") = (int) (a3); \ LOAD_ARGS_2 (a1, a2) #define ASM_ARGS_3 ASM_ARGS_2, "r" (_a3) #define LOAD_ARGS_4(a1, a2, a3, a4) \ register int _a4 asm ("a4") = (int) (a4); \ LOAD_ARGS_3 (a1, a2, a3) #define ASM_ARGS_4 ASM_ARGS_3, "r" (_a4) #define LOAD_ARGS_5(a1, a2, a3, a4, a5) \ register int _v1 asm ("v1") = (int) (a5); \ LOAD_ARGS_4 (a1, a2, a3, a4) #define ASM_ARGS_5 ASM_ARGS_4, "r" (_v1) #define LOAD_ARGS_6(a1, a2, a3, a4, a5, a6) \ register int _v2 asm ("v2") = (int) (a6); \ LOAD_ARGS_5 (a1, a2, a3, a4, a5) #define ASM_ARGS_6 ASM_ARGS_5, "r" (_v2) #define LOAD_ARGS_7(a1, a2, a3, a4, a5, a6, a7) \ register int _v3 asm ("v3") = (int) (a7); \ LOAD_ARGS_6 (a1, a2, a3, a4, a5, a6) #define ASM_ARGS_7 ASM_ARGS_6, "r" (_v3) #endif /* __ASSEMBLER__ */ #endif /* linux/arm/sysdep.h */