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-rw-r--r--libc/sysdeps/linux/arm/sysdep.h285
1 files changed, 278 insertions, 7 deletions
diff --git a/libc/sysdeps/linux/arm/sysdep.h b/libc/sysdeps/linux/arm/sysdep.h
index 3c7a182bb..0c39dfa31 100644
--- a/libc/sysdeps/linux/arm/sysdep.h
+++ b/libc/sysdeps/linux/arm/sysdep.h
@@ -17,8 +17,20 @@
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
+#ifndef _LINUX_ARM_SYSDEP_H
+#define _LINUX_ARM_SYSDEP_H 1
+
#include <common/sysdep.h>
+#include <sys/syscall.h>
+/* 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__
/* Syntactic details of assembler. */
@@ -50,7 +62,7 @@
mov pc, _reg
#endif
#else /* APCS-26 */
-#define LOADREGS(cond, base, reglist...)\
+#define LOADREGS(cond, base, reglist...) \
ldm##cond base,reglist^
#define RETINSTR(cond, reg) \
mov##cond##s pc, reg
@@ -59,15 +71,15 @@
#endif
/* Define an entry point visible from C. */
-#define ENTRY(name) \
- ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(name); \
- ASM_TYPE_DIRECTIVE (C_SYMBOL_NAME(name),function) \
- .align ALIGNARG(4); \
- name##: \
+#define ENTRY(name) \
+ ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(name); \
+ ASM_TYPE_DIRECTIVE (C_SYMBOL_NAME(name),function) \
+ .align ALIGNARG(4); \
+ name##: \
CALL_MCOUNT
#undef END
-#define END(name) \
+#define END(name) \
ASM_SIZE_DIRECTIVE(name)
/* If compiled for profiling, call `mcount' at the start of each function. */
@@ -87,5 +99,264 @@
#define syscall_error __syscall_error
#define mcount _mcount
#endif
+/* 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 safely
+ 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(cc, lr); \
+ b PLTJMP(SYSCALL_ERROR)
+#undef ret
+#define ret PSEUDO_RET
+
+#undef PSEUDO_END
+#define PSEUDO_END(name) \
+ SYSCALL_ERROR_HANDLER \
+ END (name)
+
+#undef PSEUDO_NOERRNO
+#define PSEUDO_NOERRNO(name, syscall_name, args) \
+ .text; \
+ ENTRY (name); \
+ DO_CALL (syscall_name, args);
+
+#define PSEUDO_RET_NOERRNO \
+ DO_RET (lr);
+
+#undef ret_NOERRNO
+#define ret_NOERRNO PSEUDO_RET_NOERRNO
+
+#undef PSEUDO_END_NOERRNO
+#define PSEUDO_END_NOERRNO(name) \
+ END (name)
+
+/* The function has to return the error code. */
+#undef PSEUDO_ERRVAL
+#define PSEUDO_ERRVAL(name, syscall_name, args) \
+ .text; \
+ ENTRY (name) \
+ DO_CALL (syscall_name, args); \
+ rsb r0, r0, #0
+
+#undef PSEUDO_END_ERRVAL
+#define PSEUDO_END_ERRVAL(name) \
+ END (name)
+
+#define ret_ERRVAL PSEUDO_RET_NOERRNO
+
+#if NOT_IN_libc
+# define SYSCALL_ERROR __local_syscall_error
+# ifdef RTLD_PRIVATE_ERRNO
+# define SYSCALL_ERROR_HANDLER \
+__local_syscall_error: \
+ ldr r1, 1f; \
+ rsb r0, r0, #0; \
+0: str r0, [pc, r1]; \
+ mvn r0, #0; \
+ DO_RET(lr); \
+1: .word C_SYMBOL_NAME(rtld_errno) - 0b - 8;
+# else
+# 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;
+# endif
+#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
+#if defined(__ARM_EABI__)
+#define DO_CALL(syscall_name, args) \
+ DOARGS_##args \
+ mov ip, r7; \
+ ldr r7, =SYS_ify (syscall_name); \
+ swi 0x0; \
+ mov r7, ip; \
+ UNDOARGS_##args
+#else
+#define DO_CALL(syscall_name, args) \
+ DOARGS_##args \
+ swi SYS_ify (syscall_name); \
+ UNDOARGS_##args
+#endif
+
+#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_RAW
+#if defined(__thumb__)
+/* Hide the use of r7 from the compiler, this would be a lot
+ * easier but for the fact that the syscalls can exceed 255.
+ * For the moment the LOAD_ARG_7 is sacrificed.
+ * We can't use push/pop inside the asm because that breaks
+ * unwinding (ie. thread cancellation).
+ */
+#define INTERNAL_SYSCALL_RAW(name, err, nr, args...) \
+ ({ unsigned int _sys_result; \
+ { \
+ int _sys_buf[2]; \
+ register int _a1 __asm__ ("a1"); \
+ register int *_v3 __asm__ ("v3") = _sys_buf; \
+ LOAD_ARGS_##nr (args) \
+ *_v3 = (int) (name); \
+ __asm__ __volatile__ ("str r7, [v3, #4]\n" \
+ "\tldr r7, [v3]\n" \
+ "\tswi 0 @ syscall " #name "\n" \
+ "\tldr r7, [v3, #4]" \
+ : "=r" (_a1) \
+ : "r" (_v3) ASM_ARGS_##nr \
+ : "memory"); \
+ _sys_result = _a1; \
+ } \
+ (int) _sys_result; })
+#elif defined(__ARM_EABI__)
+#define INTERNAL_SYSCALL_RAW(name, err, nr, args...) \
+ ({unsigned int _sys_result; \
+ { \
+ register int _a1 __asm__ ("r0"), _nr __asm__ ("r7"); \
+ LOAD_ARGS_##nr (args) \
+ _nr = name; \
+ __asm__ __volatile__ ("swi 0x0 @ syscall " #name \
+ : "=r" (_a1) \
+ : "r" (_nr) ASM_ARGS_##nr \
+ : "memory"); \
+ _sys_result = _a1; \
+ } \
+ (int) _sys_result; })
+#else /* !defined(__ARM_EABI__) */
+#define INTERNAL_SYSCALL_RAW(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" (name) ASM_ARGS_##nr \
+ : "memory"); \
+ _sys_result = _a1; \
+ } \
+ (int) _sys_result; })
+#endif
+
+#undef INTERNAL_SYSCALL
+#define INTERNAL_SYSCALL(name, err, nr, args...) \
+ INTERNAL_SYSCALL_RAW(SYS_ify(name), err, nr, args)
+
+#undef INTERNAL_SYSCALL_ARM
+#define INTERNAL_SYSCALL_ARM(name, err, nr, args...) \
+ INTERNAL_SYSCALL_RAW(__ARM_NR_##name, err, nr, args)
+
+#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))
+
+#if defined(__ARM_EABI__)
+#undef INTERNAL_SYSCALL_NCS
+#define INTERNAL_SYSCALL_NCS(number, err, nr, args...) \
+ INTERNAL_SYSCALL_RAW(number, err, nr, args)
+#else
+/* We can't implement non-constant syscalls directly since the syscall
+ number is normally encoded in the instruction. So use SYS_syscall. */
+#undef INTERNAL_SYSCALL_NCS
+#define INTERNAL_SYSCALL_NCS(number, err, nr, args...) \
+ INTERNAL_SYSCALL_NCS_##nr (number, err, args)
+
+#define INTERNAL_SYSCALL_NCS_0(number, err, args...) \
+ INTERNAL_SYSCALL (syscall, err, 1, number, args)
+#define INTERNAL_SYSCALL_NCS_1(number, err, args...) \
+ INTERNAL_SYSCALL (syscall, err, 2, number, args)
+#define INTERNAL_SYSCALL_NCS_2(number, err, args...) \
+ INTERNAL_SYSCALL (syscall, err, 3, number, args)
+#define INTERNAL_SYSCALL_NCS_3(number, err, args...) \
+ INTERNAL_SYSCALL (syscall, err, 4, number, args)
+#define INTERNAL_SYSCALL_NCS_4(number, err, args...) \
+ INTERNAL_SYSCALL (syscall, err, 5, number, args)
+#define INTERNAL_SYSCALL_NCS_5(number, err, args...) \
+ INTERNAL_SYSCALL (syscall, err, 6, number, args)
+#endif
#endif /* __ASSEMBLER__ */
+#endif /* linux/arm/sysdep.h */