diff options
Diffstat (limited to 'libc/sysdeps/linux/xtensa/bits/syscalls.h')
| -rw-r--r-- | libc/sysdeps/linux/xtensa/bits/syscalls.h | 140 |
1 files changed, 140 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/xtensa/bits/syscalls.h b/libc/sysdeps/linux/xtensa/bits/syscalls.h new file mode 100644 index 000000000..76bcf404f --- /dev/null +++ b/libc/sysdeps/linux/xtensa/bits/syscalls.h @@ -0,0 +1,140 @@ +#ifndef _BITS_SYSCALLS_H +#define _BITS_SYSCALLS_H +#ifndef _SYSCALL_H +# error "Never use <bits/syscalls.h> directly; include <sys/syscall.h> instead." +#endif + +/* + Some of the sneaky macros in the code were taken from + glibc .../sysdeps/unix/sysv/linux/xtensa/sysdep.h +*/ + +#define SYS_ify(syscall_name) __NR_##syscall_name + +#ifdef __ASSEMBLER__ + +/* The register layout upon entering the function is: + + return addr stack ptr arg0, arg1, arg2, arg3, arg4, arg5 + ----------- --------- ---------------------------------- + a0 a1 a2, a3, a4, a5, a6, a7 + + (Of course a function with say 3 arguments does not have entries for + arguments 4, 5, and 6.) + + Linux takes system-call arguments in registers. The ABI and Xtensa + software conventions require the system-call number in a2. We move any + argument that was in a2 to a7, and a7 to a8 if we have all 6 arguments. + Note that for improved efficiency, we do NOT shift all parameters down + one register to maintain the original order. + + syscall number arg0, arg1, arg2, arg3, arg4, arg5 + -------------- ---------------------------------- + a2 a6, a3, a4, a5, a8, a9 + + Upon return, a2 and a3 are clobbered; all other registers are preserved. */ + +#undef DO_CALL +#define DO_CALL(syscall_name, nargs) \ + DO_ARGS_##nargs \ + movi a2, SYS_ify (syscall_name); \ + syscall + +#define DO_ARGS_0 +#define DO_ARGS_1 mov a6, a2; +#define DO_ARGS_2 mov a6, a2; +#define DO_ARGS_3 mov a6, a2; +#define DO_ARGS_4 mov a6, a2; +#define DO_ARGS_5 mov a8, a6; mov a6, a2; +#define DO_ARGS_6 mov a9, a7; mov a8, a6; mov a6, a2; + +#else /* not __ASSEMBLER__ */ + +#include <errno.h> + +#define STR(s) #s +#define LD_ARG(n,ar) register int _a##n asm (STR(a##n)) = (int) (ar) + +#define LD_ARGS_0() +#define LD_ARGS_1(a0) LD_ARG(6,a0) +#define LD_ARGS_2(a0,a1) LD_ARGS_1(a0); LD_ARG(3,a1) +#define LD_ARGS_3(a0,a1,a2) LD_ARGS_2(a0,a1); LD_ARG(4,a2) +#define LD_ARGS_4(a0,a1,a2,a3) LD_ARGS_3(a0,a1,a2); LD_ARG(5,a3) +#define LD_ARGS_5(a0,a1,a2,a3,a4) LD_ARGS_4(a0,a1,a2,a3); LD_ARG(8,a4) +#define LD_ARGS_6(a0,a1,a2,a3,a4,a5) LD_ARGS_5(a0,a1,a2,a3,a4); LD_ARG(9,a5) + +#define ASM_ARGS_0 "r"(_a2) +#define ASM_ARGS_1 ASM_ARGS_0, "r"(_a6) +#define ASM_ARGS_2 ASM_ARGS_1, "r"(_a3) +#define ASM_ARGS_3 ASM_ARGS_2, "r"(_a4) +#define ASM_ARGS_4 ASM_ARGS_3, "r"(_a5) +#define ASM_ARGS_5 ASM_ARGS_4, "r"(_a8) +#define ASM_ARGS_6 ASM_ARGS_5, "r"(_a9) + +/* Define a macro which expands into the inline wrapper code for a system + call. */ + +#undef INLINE_SYSCALL +#define INLINE_SYSCALL(name, nr, args...) \ + ({ unsigned long resultvar = INTERNAL_SYSCALL (name, , nr, args); \ + if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (resultvar, ), 0)) \ + { \ + __set_errno (INTERNAL_SYSCALL_ERRNO (resultvar, )); \ + resultvar = (unsigned long) -1; \ + } \ + (long) resultvar; }) + +#undef INTERNAL_SYSCALL_DECL +#define INTERNAL_SYSCALL_DECL(err) do { } while (0) + +#define INTERNAL_SYSCALL_NCS(name, err, nr, args...) \ + ({ LD_ARG(2, name); \ + LD_ARGS_##nr(args); \ + asm volatile ("syscall\n" \ + : "=a" (_a2) \ + : ASM_ARGS_##nr \ + : "memory"); \ + (long) _a2; }) + +#undef INTERNAL_SYSCALL +#define INTERNAL_SYSCALL(name, err, nr, args...) \ + INTERNAL_SYSCALL_NCS (__NR_##name, err, nr, ##args) + +#undef INTERNAL_SYSCALL_ERROR_P +#define INTERNAL_SYSCALL_ERROR_P(val, err) \ + ((unsigned long) (val) >= -4095L) + +#undef INTERNAL_SYSCALL_ERRNO +#define INTERNAL_SYSCALL_ERRNO(val, err) (-(val)) + +#define _syscall0(args...) SYSCALL_FUNC (0, args) +#define _syscall1(args...) SYSCALL_FUNC (1, args) +#define _syscall2(args...) SYSCALL_FUNC (2, args) +#define _syscall3(args...) SYSCALL_FUNC (3, args) +#define _syscall4(args...) SYSCALL_FUNC (4, args) +#define _syscall5(args...) SYSCALL_FUNC (5, args) +#define _syscall6(args...) SYSCALL_FUNC (6, args) + +#define C_DECL_ARGS_0() void +#define C_DECL_ARGS_1(t, v) t v +#define C_DECL_ARGS_2(t, v, args...) t v, C_DECL_ARGS_1(args) +#define C_DECL_ARGS_3(t, v, args...) t v, C_DECL_ARGS_2(args) +#define C_DECL_ARGS_4(t, v, args...) t v, C_DECL_ARGS_3(args) +#define C_DECL_ARGS_5(t, v, args...) t v, C_DECL_ARGS_4(args) +#define C_DECL_ARGS_6(t, v, args...) t v, C_DECL_ARGS_5(args) + +#define C_ARGS_0() +#define C_ARGS_1(t, v) v +#define C_ARGS_2(t, v, args...) v, C_ARGS_1 (args) +#define C_ARGS_3(t, v, args...) v, C_ARGS_2 (args) +#define C_ARGS_4(t, v, args...) v, C_ARGS_3 (args) +#define C_ARGS_5(t, v, args...) v, C_ARGS_4 (args) +#define C_ARGS_6(t, v, args...) v, C_ARGS_5 (args) + +#define SYSCALL_FUNC(nargs, type, name, args...) \ +type name (C_DECL_ARGS_##nargs (args)) { \ + return (type) INLINE_SYSCALL (name, nargs, C_ARGS_##nargs (args)); \ +} + +#endif /* not __ASSEMBLER__ */ +#endif /* _BITS_SYSCALLS_H */ |