[thirdparty/glibc.git] / ports / sysdeps / unix / sysv / linux / arm / sysdep.h

/* Copyright (C) 1992-2013 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper, <drepper@gnu.ai.mit.edu>, August 1995.
   ARM changes by Philip Blundell, <pjb27@cam.ac.uk>, 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, see
   <http://www.gnu.org/licenses/>.  */

#ifndef _LINUX_ARM_SYSDEP_H
#define _LINUX_ARM_SYSDEP_H 1

/* There is some commonality.  */
#include <sysdeps/unix/arm/sysdep.h>

/* Defines RTLD_PRIVATE_ERRNO and USE_DL_SYSINFO.  */
#include <dl-sysdep.h>

#include <tls.h>

/* In order to get __set_errno() definition in INLINE_SYSCALL.  */
#ifndef __ASSEMBLER__
#include <errno.h>
#endif

/* 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 SYS_ify(syscall_name)	(__NR_##syscall_name)

#define _SYS_AUXV_H 1
#include <bits/hwcap.h>

#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 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
# if 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
#  if defined(__ARM_ARCH_4T__) && defined(__THUMB_INTERWORK__)
#   define POP_PC \
  ldr lr, [sp], #4; \
  cfi_adjust_cfa_offset (-4); \
  cfi_restore (lr); \
  bx lr
#  else
#   define POP_PC  \
  ldr pc, [sp], #4
#  endif
#  define SYSCALL_ERROR_HANDLER					\
__local_syscall_error:						\
	str	lr, [sp, #-4]!;					\
	cfi_adjust_cfa_offset (4);				\
	cfi_rel_offset (lr, 0);					\
	str	r0, [sp, #-4]!;					\
	cfi_adjust_cfa_offset (4);				\
	bl	PLTJMP(C_SYMBOL_NAME(__errno_location)); 	\
	ldr	r1, [sp], #4;					\
	cfi_adjust_cfa_offset (-4);				\
	rsb	r1, r1, #0;					\
	str	r1, [r0];					\
	mvn	r0, #0;						\
	POP_PC;
# endif
#else
# define SYSCALL_ERROR_HANDLER	/* Nothing here; code in sysdep.S is used.  */
# define SYSCALL_ERROR __syscall_error
#endif

/* The ARM EABI user interface passes the syscall number in r7, instead
   of in the swi.  This is more efficient, because the kernel does not need
   to fetch the swi from memory to find out the number; which can be painful
   with separate I-cache and D-cache.  Make sure to use 0 for the SWI
   argument; otherwise the (optional) compatibility code for APCS binaries
   may be invoked.  */

/* Linux takes system call args in registers:
	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.

*/

/* We must save and restore r7 (call-saved) for the syscall number.
   We never make function calls from inside here (only potentially
   signal handlers), so we do not bother with doubleword alignment.

   Just like the APCS syscall convention, the EABI syscall convention uses
   r0 through r6 for up to seven syscall arguments.  None are ever passed to
   the kernel on the stack, although incoming arguments are on the stack for
   syscalls with five or more arguments.

   The assembler will convert the literal pool load to a move for most
   syscalls.  */

#undef	DO_CALL
#define DO_CALL(syscall_name, args)		\
    DOARGS_##args;				\
    ldr r7, =SYS_ify (syscall_name);		\
    swi 0x0;					\
    UNDOARGS_##args

#undef  DOARGS_0
#define DOARGS_0 \
  .fnstart; \
  str r7, [sp, #-4]!; \
  cfi_adjust_cfa_offset (4); \
  cfi_rel_offset (r7, 0); \
  .save { r7 }
#undef  DOARGS_1
#define DOARGS_1 DOARGS_0
#undef  DOARGS_2
#define DOARGS_2 DOARGS_0
#undef  DOARGS_3
#define DOARGS_3 DOARGS_0
#undef  DOARGS_4
#define DOARGS_4 DOARGS_0
#undef  DOARGS_5
#define DOARGS_5 \
  .fnstart; \
  stmfd sp!, {r4, r7}; \
  cfi_adjust_cfa_offset (8); \
  cfi_rel_offset (r4, 0); \
  cfi_rel_offset (r7, 4); \
  .save { r4, r7 }; \
  ldr r4, [sp, #8]
#undef  DOARGS_6
#define DOARGS_6 \
  .fnstart; \
  mov ip, sp; \
  stmfd sp!, {r4, r5, r7}; \
  cfi_adjust_cfa_offset (12); \
  cfi_rel_offset (r4, 0); \
  cfi_rel_offset (r5, 4); \
  cfi_rel_offset (r7, 8); \
  .save { r4, r5, r7 }; \
  ldmia ip, {r4, r5}
#undef  DOARGS_7
#define DOARGS_7 \
  .fnstart; \
  mov ip, sp; \
  stmfd sp!, {r4, r5, r6, r7}; \
  cfi_adjust_cfa_offset (16); \
  cfi_rel_offset (r4, 0); \
  cfi_rel_offset (r5, 4); \
  cfi_rel_offset (r6, 8); \
  cfi_rel_offset (r7, 12); \
  .save { r4, r5, r6, r7 }; \
  ldmia ip, {r4, r5, r6}

#undef  UNDOARGS_0
#define UNDOARGS_0 \
  ldr r7, [sp], #4; \
  cfi_adjust_cfa_offset (-4); \
  cfi_restore (r7); \
  .fnend
#undef  UNDOARGS_1
#define UNDOARGS_1 UNDOARGS_0
#undef  UNDOARGS_2
#define UNDOARGS_2 UNDOARGS_0
#undef  UNDOARGS_3
#define UNDOARGS_3 UNDOARGS_0
#undef  UNDOARGS_4
#define UNDOARGS_4 UNDOARGS_0
#undef  UNDOARGS_5
#define UNDOARGS_5 \
  ldmfd sp!, {r4, r7}; \
  cfi_adjust_cfa_offset (-8); \
  cfi_restore (r4); \
  cfi_restore (r7); \
  .fnend
#undef  UNDOARGS_6
#define UNDOARGS_6 \
  ldmfd sp!, {r4, r5, r7}; \
  cfi_adjust_cfa_offset (-12); \
  cfi_restore (r4); \
  cfi_restore (r5); \
  cfi_restore (r7); \
  .fnend
#undef  UNDOARGS_7
#define UNDOARGS_7 \
  ldmfd sp!, {r4, r5, r6, r7}; \
  cfi_adjust_cfa_offset (-16); \
  cfi_restore (r4); \
  cfi_restore (r5); \
  cfi_restore (r6); \
  cfi_restore (r7); \
  .fnend

#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)

#if defined(__thumb__)
/* We can not expose the use of r7 to the compiler.  GCC (as
   of 4.5) uses r7 as the hard frame pointer for Thumb - although
   for Thumb-2 it isn't obviously a better choice than r11.
   And GCC does not support asms that conflict with the frame
   pointer.

   This would be easier if syscall numbers never exceeded 255,
   but they do.  For the moment the LOAD_ARGS_7 is sacrificed.
   We can't use push/pop inside the asm because that breaks
   unwinding (i.e. thread cancellation) for this frame.  We can't
   locally save and restore r7, because we do not know if this
   function uses r7 or if it is our caller's r7; if it is our caller's,
   then unwinding will fail higher up the stack.  So we move the
   syscall out of line and provide its own unwind information.  */
# undef INTERNAL_SYSCALL_RAW
# define INTERNAL_SYSCALL_RAW(name, err, nr, args...)		\
  ({								\
      register int _a1 asm ("a1");				\
      int _nametmp = name;					\
      LOAD_ARGS_##nr (args)					\
      register int _name asm ("ip") = _nametmp;			\
      asm volatile ("bl      __libc_do_syscall"			\
                    : "=r" (_a1)				\
                    : "r" (_name) ASM_ARGS_##nr			\
                    : "memory", "lr");				\
      _a1; })
#else /* ARM */
# undef INTERNAL_SYSCALL_RAW
# define INTERNAL_SYSCALL_RAW(name, err, nr, args...)		\
  ({								\
       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");				\
       _a1; })
#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))

#define LOAD_ARGS_0()
#define ASM_ARGS_0
#define LOAD_ARGS_1(a1)				\
  int _a1tmp = (int) (a1);			\
  LOAD_ARGS_0 ()				\
  _a1 = _a1tmp;
#define ASM_ARGS_1	ASM_ARGS_0, "r" (_a1)
#define LOAD_ARGS_2(a1, a2)			\
  int _a2tmp = (int) (a2);			\
  LOAD_ARGS_1 (a1)				\
  register int _a2 asm ("a2") = _a2tmp;
#define ASM_ARGS_2	ASM_ARGS_1, "r" (_a2)
#define LOAD_ARGS_3(a1, a2, a3)			\
  int _a3tmp = (int) (a3);			\
  LOAD_ARGS_2 (a1, a2)				\
  register int _a3 asm ("a3") = _a3tmp;
#define ASM_ARGS_3	ASM_ARGS_2, "r" (_a3)
#define LOAD_ARGS_4(a1, a2, a3, a4)		\
  int _a4tmp = (int) (a4);			\
  LOAD_ARGS_3 (a1, a2, a3)			\
  register int _a4 asm ("a4") = _a4tmp;
#define ASM_ARGS_4	ASM_ARGS_3, "r" (_a4)
#define LOAD_ARGS_5(a1, a2, a3, a4, a5)		\
  int _v1tmp = (int) (a5);			\
  LOAD_ARGS_4 (a1, a2, a3, a4)			\
  register int _v1 asm ("v1") = _v1tmp;
#define ASM_ARGS_5	ASM_ARGS_4, "r" (_v1)
#define LOAD_ARGS_6(a1, a2, a3, a4, a5, a6)	\
  int _v2tmp = (int) (a6);			\
  LOAD_ARGS_5 (a1, a2, a3, a4, a5)		\
  register int _v2 asm ("v2") = _v2tmp;
#define ASM_ARGS_6	ASM_ARGS_5, "r" (_v2)
#ifndef __thumb__
# define LOAD_ARGS_7(a1, a2, a3, a4, a5, a6, a7)	\
  int _v3tmp = (int) (a7);				\
  LOAD_ARGS_6 (a1, a2, a3, a4, a5, a6)			\
  register int _v3 asm ("v3") = _v3tmp;
# define ASM_ARGS_7	ASM_ARGS_6, "r" (_v3)
#endif

/* For EABI, non-constant syscalls are actually pretty easy...  */
#undef INTERNAL_SYSCALL_NCS
#define INTERNAL_SYSCALL_NCS(number, err, nr, args...)          \
  INTERNAL_SYSCALL_RAW (number, err, nr, args)

#endif	/* __ASSEMBLER__ */

/* Pointer mangling is not yet supported for ARM.  */
#define PTR_MANGLE(var) (void) (var)
#define PTR_DEMANGLE(var) (void) (var)

#endif /* linux/arm/sysdep.h */
Commit	Line	Data
568035b7	1	/* Copyright (C) 1992-2013 Free Software Foundation, Inc.
c751295f UD	2	This file is part of the GNU C Library.
	3	Contributed by Ulrich Drepper, <drepper@gnu.ai.mit.edu>, August 1995.
	4	ARM changes by Philip Blundell, <pjb27@cam.ac.uk>, May 1997.
8d2485ed	5
c751295f	6	The GNU C Library is free software; you can redistribute it and/or
3214b89b AJ	7	modify it under the terms of the GNU Lesser General Public
	8	License as published by the Free Software Foundation; either
	9	version 2.1 of the License, or (at your option) any later version.
8d2485ed	10
c751295f UD	11	The GNU C Library is distributed in the hope that it will be useful,
	12	but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
3214b89b	14	Lesser General Public License for more details.
8d2485ed	15
3214b89b	16	You should have received a copy of the GNU Lesser General Public
ab84e3ff PE	17	License along with the GNU C Library. If not, see
ab84e3ff PE	18	<http://www.gnu.org/licenses/>. */
8d2485ed UD	19
	20	#ifndef _LINUX_ARM_SYSDEP_H
	21	#define _LINUX_ARM_SYSDEP_H 1
	22
	23	/* There is some commonality. */
16c82ad7	24	#include <sysdeps/unix/arm/sysdep.h>
8d2485ed	25
02a9f771 DJ	26	/* Defines RTLD_PRIVATE_ERRNO and USE_DL_SYSINFO. */
	27	#include <dl-sysdep.h>
	28
a68f927f DJ	29	#include <tls.h>
a68f927f DJ	30
26ed7fb1 JM	31	/* In order to get __set_errno() definition in INLINE_SYSCALL. */
	32	#ifndef __ASSEMBLER__
	33	#include <errno.h>
	34	#endif
	35
8d2485ed UD	36	/* For Linux we can use the system call table in the header file
	37	/usr/include/asm/unistd.h
	38	of the kernel. But these symbols do not follow the SYS_* syntax
	39	so we have to redefine the `SYS_ify' macro here. */
	40	#undef SYS_ify
d2099b0d	41	#define SYS_ify(syscall_name) (__NR_##syscall_name)
8d2485ed	42
c0ddea5a JM	43	#define _SYS_AUXV_H 1
c0ddea5a JM	44	#include <bits/hwcap.h>
4b860fb9	45
e0ebc3b2	46	#ifdef __ASSEMBLER__
8d2485ed UD	47
	48	/* Linux uses a negative return value to indicate syscall errors,
	49	unlike most Unices, which use the condition codes' carry flag.
	50
	51	Since version 2.1 the return value of a system call might be
	52	negative even if the call succeeded. E.g., the `lseek' system call
	53	might return a large offset. Therefore we must not anymore test
0f2a261a	54	for < 0, but test for a real error by making sure the value in R0
8d2485ed	55	is a real error number. Linus said he will make sure the no syscall
02a9f771	56	returns a value in -1 .. -4095 as a valid result so we can safely
8d2485ed	57	test with -4095. */
ff550b1f	58
8d2485ed UD	59	#undef PSEUDO
	60	#define PSEUDO(name, syscall_name, args) \
	61	.text; \
86ffa1b4	62	ENTRY (name); \
631d94cb	63	DO_CALL (syscall_name, args); \
63ac74aa UD	64	cmn r0, $4096;
	65
	66	#define PSEUDO_RET \
47f0752a	67	RETINSTR(cc, lr); \
2f0910ca	68	b PLTJMP(SYSCALL_ERROR)
63ac74aa UD	69	#undef ret
63ac74aa UD	70	#define ret PSEUDO_RET
8d2485ed UD	71
	72	#undef PSEUDO_END
	73	#define PSEUDO_END(name) \
01b32e73	74	SYSCALL_ERROR_HANDLER; \
8d2485ed UD	75	END (name)
8d2485ed UD	76
98f7320f UD	77	#undef PSEUDO_NOERRNO
	78	#define PSEUDO_NOERRNO(name, syscall_name, args) \
	79	.text; \
	80	ENTRY (name); \
	81	DO_CALL (syscall_name, args);
	82
	83	#define PSEUDO_RET_NOERRNO \
47f0752a	84	DO_RET (lr);
44acff5d	85
98f7320f UD	86	#undef ret_NOERRNO
	87	#define ret_NOERRNO PSEUDO_RET_NOERRNO
	88
	89	#undef PSEUDO_END_NOERRNO
	90	#define PSEUDO_END_NOERRNO(name) \
	91	END (name)
	92
ae53e7a7 UD	93	/* The function has to return the error code. */
	94	#undef PSEUDO_ERRVAL
	95	#define PSEUDO_ERRVAL(name, syscall_name, args) \
	96	.text; \
	97	ENTRY (name) \
	98	DO_CALL (syscall_name, args); \
	99	rsb r0, r0, #0
	100
	101	#undef PSEUDO_END_ERRVAL
	102	#define PSEUDO_END_ERRVAL(name) \
	103	END (name)
	104
	105	#define ret_ERRVAL PSEUDO_RET_NOERRNO
	106
2f0910ca UD	107	#if NOT_IN_libc
2f0910ca UD	108	# define SYSCALL_ERROR __local_syscall_error
02a9f771 DJ	109	# if RTLD_PRIVATE_ERRNO
	110	# define SYSCALL_ERROR_HANDLER \
	111	__local_syscall_error: \
	112	ldr r1, 1f; \
	113	rsb r0, r0, #0; \
	114	0: str r0, [pc, r1]; \
	115	mvn r0, #0; \
	116	DO_RET(lr); \
	117	1: .word C_SYMBOL_NAME(rtld_errno) - 0b - 8;
	118	# else
01b32e73 TS	119	# if defined(__ARM_ARCH_4T__) && defined(__THUMB_INTERWORK__)
	120	# define POP_PC \
	121	ldr lr, [sp], #4; \
	122	cfi_adjust_cfa_offset (-4); \
	123	cfi_restore (lr); \
	124	bx lr
	125	# else
	126	# define POP_PC \
	127	ldr pc, [sp], #4
	128	# endif
02a9f771	129	# define SYSCALL_ERROR_HANDLER \
2f0910ca UD	130	__local_syscall_error: \
2f0910ca UD	131	str lr, [sp, #-4]!; \
01b32e73 TS	132	cfi_adjust_cfa_offset (4); \
01b32e73 TS	133	cfi_rel_offset (lr, 0); \
2f0910ca	134	str r0, [sp, #-4]!; \
01b32e73	135	cfi_adjust_cfa_offset (4); \
2f0910ca UD	136	bl PLTJMP(C_SYMBOL_NAME(__errno_location)); \
2f0910ca UD	137	ldr r1, [sp], #4; \
01b32e73	138	cfi_adjust_cfa_offset (-4); \
2f0910ca UD	139	rsb r1, r1, #0; \
	140	str r1, [r0]; \
	141	mvn r0, #0; \
b2b2415f	142	POP_PC;
02a9f771	143	# endif
2f0910ca UD	144	#else
	145	# define SYSCALL_ERROR_HANDLER /* Nothing here; code in sysdep.S is used. */
	146	# define SYSCALL_ERROR __syscall_error
	147	#endif
ff550b1f	148
25593dca JM	149	/* The ARM EABI user interface passes the syscall number in r7, instead
	150	of in the swi. This is more efficient, because the kernel does not need
	151	to fetch the swi from memory to find out the number; which can be painful
	152	with separate I-cache and D-cache. Make sure to use 0 for the SWI
	153	argument; otherwise the (optional) compatibility code for APCS binaries
	154	may be invoked. */
	155
ff550b1f	156	/* Linux takes system call args in registers:
ff550b1f UD	157	arg 1 r0
	158	arg 2 r1
	159	arg 3 r2
	160	arg 4 r3
	161	arg 5 r4 (this is different from the APCS convention)
62749187 UD	162	arg 6 r5
62749187 UD	163	arg 7 r6
ff550b1f UD	164
	165	The compiler is going to form a call by coming here, through PSEUDO, with
	166	arguments
	167	syscall number in the DO_CALL macro
	168	arg 1 r0
	169	arg 2 r1
	170	arg 3 r2
	171	arg 4 r3
	172	arg 5 [sp]
62749187 UD	173	arg 6 [sp+4]
62749187 UD	174	arg 7 [sp+8]
ff550b1f	175
62749187 UD	176	We need to shuffle values between R4..R6 and the stack so that the
	177	caller's v1..v3 and stack frame are not corrupted, and the kernel
	178	sees the right arguments.
ff550b1f UD	179
ff550b1f UD	180	*/
8d2485ed	181
25593dca JM	182	/* We must save and restore r7 (call-saved) for the syscall number.
	183	We never make function calls from inside here (only potentially
	184	signal handlers), so we do not bother with doubleword alignment.
	185
	186	Just like the APCS syscall convention, the EABI syscall convention uses
	187	r0 through r6 for up to seven syscall arguments. None are ever passed to
	188	the kernel on the stack, although incoming arguments are on the stack for
	189	syscalls with five or more arguments.
	190
	191	The assembler will convert the literal pool load to a move for most
	192	syscalls. */
	193
8d2485ed	194	#undef DO_CALL
631d94cb	195	#define DO_CALL(syscall_name, args) \
01b32e73	196	DOARGS_##args; \
25593dca JM	197	ldr r7, =SYS_ify (syscall_name); \
25593dca JM	198	swi 0x0; \
ff550b1f UD	199	UNDOARGS_##args
ff550b1f UD	200
25593dca JM	201	#undef DOARGS_0
	202	#define DOARGS_0 \
	203	.fnstart; \
	204	str r7, [sp, #-4]!; \
01b32e73	205	cfi_adjust_cfa_offset (4); \
25593dca JM	206	cfi_rel_offset (r7, 0); \
	207	.save { r7 }
	208	#undef DOARGS_1
	209	#define DOARGS_1 DOARGS_0
	210	#undef DOARGS_2
	211	#define DOARGS_2 DOARGS_0
	212	#undef DOARGS_3
	213	#define DOARGS_3 DOARGS_0
	214	#undef DOARGS_4
	215	#define DOARGS_4 DOARGS_0
	216	#undef DOARGS_5
	217	#define DOARGS_5 \
	218	.fnstart; \
	219	stmfd sp!, {r4, r7}; \
	220	cfi_adjust_cfa_offset (8); \
01b32e73	221	cfi_rel_offset (r4, 0); \
25593dca JM	222	cfi_rel_offset (r7, 4); \
	223	.save { r4, r7 }; \
	224	ldr r4, [sp, #8]
	225	#undef DOARGS_6
01b32e73	226	#define DOARGS_6 \
25593dca	227	.fnstart; \
01b32e73	228	mov ip, sp; \
25593dca JM	229	stmfd sp!, {r4, r5, r7}; \
25593dca JM	230	cfi_adjust_cfa_offset (12); \
01b32e73 TS	231	cfi_rel_offset (r4, 0); \
01b32e73 TS	232	cfi_rel_offset (r5, 4); \
25593dca JM	233	cfi_rel_offset (r7, 8); \
25593dca JM	234	.save { r4, r5, r7 }; \
01b32e73	235	ldmia ip, {r4, r5}
25593dca	236	#undef DOARGS_7
01b32e73	237	#define DOARGS_7 \
25593dca	238	.fnstart; \
01b32e73	239	mov ip, sp; \
25593dca JM	240	stmfd sp!, {r4, r5, r6, r7}; \
25593dca JM	241	cfi_adjust_cfa_offset (16); \
01b32e73 TS	242	cfi_rel_offset (r4, 0); \
	243	cfi_rel_offset (r5, 4); \
	244	cfi_rel_offset (r6, 8); \
25593dca JM	245	cfi_rel_offset (r7, 12); \
25593dca JM	246	.save { r4, r5, r6, r7 }; \
01b32e73	247	ldmia ip, {r4, r5, r6}
ff550b1f	248
25593dca JM	249	#undef UNDOARGS_0
	250	#define UNDOARGS_0 \
	251	ldr r7, [sp], #4; \
01b32e73	252	cfi_adjust_cfa_offset (-4); \
25593dca JM	253	cfi_restore (r7); \
	254	.fnend
	255	#undef UNDOARGS_1
	256	#define UNDOARGS_1 UNDOARGS_0
	257	#undef UNDOARGS_2
	258	#define UNDOARGS_2 UNDOARGS_0
	259	#undef UNDOARGS_3
	260	#define UNDOARGS_3 UNDOARGS_0
	261	#undef UNDOARGS_4
	262	#define UNDOARGS_4 UNDOARGS_0
	263	#undef UNDOARGS_5
	264	#define UNDOARGS_5 \
	265	ldmfd sp!, {r4, r7}; \
01b32e73 TS	266	cfi_adjust_cfa_offset (-8); \
01b32e73 TS	267	cfi_restore (r4); \
25593dca JM	268	cfi_restore (r7); \
	269	.fnend
	270	#undef UNDOARGS_6
	271	#define UNDOARGS_6 \
	272	ldmfd sp!, {r4, r5, r7}; \
01b32e73 TS	273	cfi_adjust_cfa_offset (-12); \
	274	cfi_restore (r4); \
	275	cfi_restore (r5); \
25593dca JM	276	cfi_restore (r7); \
	277	.fnend
	278	#undef UNDOARGS_7
	279	#define UNDOARGS_7 \
	280	ldmfd sp!, {r4, r5, r6, r7}; \
	281	cfi_adjust_cfa_offset (-16); \
	282	cfi_restore (r4); \
	283	cfi_restore (r5); \
	284	cfi_restore (r6); \
	285	cfi_restore (r7); \
	286	.fnend
8d2485ed	287
ba023f01 UD	288	#else /* not __ASSEMBLER__ */
	289
	290	/* Define a macro which expands into the inline wrapper code for a system
	291	call. */
	292	#undef INLINE_SYSCALL
2f0910ca	293	#define INLINE_SYSCALL(name, nr, args...) \
114e7d50 UD	294	({ unsigned int _sys_result = INTERNAL_SYSCALL (name, , nr, args); \
114e7d50 UD	295	if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (_sys_result, ), 0)) \
2f0910ca	296	{ \
114e7d50	297	__set_errno (INTERNAL_SYSCALL_ERRNO (_sys_result, )); \
2f0910ca UD	298	_sys_result = (unsigned int) -1; \
	299	} \
	300	(int) _sys_result; })
	301
aeeec7fb UD	302	#undef INTERNAL_SYSCALL_DECL
	303	#define INTERNAL_SYSCALL_DECL(err) do { } while (0)
	304
25593dca JM	305	#if defined(__thumb__)
	306	/* We can not expose the use of r7 to the compiler. GCC (as
	307	of 4.5) uses r7 as the hard frame pointer for Thumb - although
	308	for Thumb-2 it isn't obviously a better choice than r11.
	309	And GCC does not support asms that conflict with the frame
	310	pointer.
	311
	312	This would be easier if syscall numbers never exceeded 255,
	313	but they do. For the moment the LOAD_ARGS_7 is sacrificed.
	314	We can't use push/pop inside the asm because that breaks
	315	unwinding (i.e. thread cancellation) for this frame. We can't
	316	locally save and restore r7, because we do not know if this
	317	function uses r7 or if it is our caller's r7; if it is our caller's,
	318	then unwinding will fail higher up the stack. So we move the
	319	syscall out of line and provide its own unwind information. */
	320	# undef INTERNAL_SYSCALL_RAW
	321	# define INTERNAL_SYSCALL_RAW(name, err, nr, args...) \
	322	({ \
	323	register int _a1 asm ("a1"); \
	324	int _nametmp = name; \
	325	LOAD_ARGS_##nr (args) \
	326	register int _name asm ("ip") = _nametmp; \
	327	asm volatile ("bl __libc_do_syscall" \
	328	: "=r" (_a1) \
	329	: "r" (_name) ASM_ARGS_##nr \
	330	: "memory", "lr"); \
	331	_a1; })
	332	#else /* ARM */
	333	# undef INTERNAL_SYSCALL_RAW
	334	# define INTERNAL_SYSCALL_RAW(name, err, nr, args...) \
	335	({ \
	336	register int _a1 asm ("r0"), _nr asm ("r7"); \
ba023f01	337	LOAD_ARGS_##nr (args) \
25593dca JM	338	_nr = name; \
25593dca JM	339	asm volatile ("swi 0x0 @ syscall " #name \
ba023f01	340	: "=r" (_a1) \
25593dca	341	: "r" (_nr) ASM_ARGS_##nr \
cf666e4b	342	: "memory"); \
25593dca JM	343	_a1; })
25593dca JM	344	#endif
ba023f01	345
485a9bb9 DJ	346	#undef INTERNAL_SYSCALL
	347	#define INTERNAL_SYSCALL(name, err, nr, args...) \
	348	INTERNAL_SYSCALL_RAW(SYS_ify(name), err, nr, args)
	349
	350	#undef INTERNAL_SYSCALL_ARM
	351	#define INTERNAL_SYSCALL_ARM(name, err, nr, args...) \
	352	INTERNAL_SYSCALL_RAW(__ARM_NR_##name, err, nr, args)
	353
2f0910ca	354	#undef INTERNAL_SYSCALL_ERROR_P
aeeec7fb UD	355	#define INTERNAL_SYSCALL_ERROR_P(val, err) \
aeeec7fb UD	356	((unsigned int) (val) >= 0xfffff001u)
2f0910ca UD	357
2f0910ca UD	358	#undef INTERNAL_SYSCALL_ERRNO
aeeec7fb	359	#define INTERNAL_SYSCALL_ERRNO(val, err) (-(val))
2f0910ca	360
ba023f01 UD	361	#define LOAD_ARGS_0()
	362	#define ASM_ARGS_0
	363	#define LOAD_ARGS_1(a1) \
9806fbba JM	364	int _a1tmp = (int) (a1); \
	365	LOAD_ARGS_0 () \
	366	_a1 = _a1tmp;
ba023f01 UD	367	#define ASM_ARGS_1 ASM_ARGS_0, "r" (_a1)
ba023f01 UD	368	#define LOAD_ARGS_2(a1, a2) \
9806fbba JM	369	int _a2tmp = (int) (a2); \
	370	LOAD_ARGS_1 (a1) \
	371	register int _a2 asm ("a2") = _a2tmp;
ba023f01 UD	372	#define ASM_ARGS_2 ASM_ARGS_1, "r" (_a2)
ba023f01 UD	373	#define LOAD_ARGS_3(a1, a2, a3) \
9806fbba JM	374	int _a3tmp = (int) (a3); \
	375	LOAD_ARGS_2 (a1, a2) \
	376	register int _a3 asm ("a3") = _a3tmp;
ba023f01 UD	377	#define ASM_ARGS_3 ASM_ARGS_2, "r" (_a3)
ba023f01 UD	378	#define LOAD_ARGS_4(a1, a2, a3, a4) \
9806fbba JM	379	int _a4tmp = (int) (a4); \
	380	LOAD_ARGS_3 (a1, a2, a3) \
	381	register int _a4 asm ("a4") = _a4tmp;
ba023f01 UD	382	#define ASM_ARGS_4 ASM_ARGS_3, "r" (_a4)
ba023f01 UD	383	#define LOAD_ARGS_5(a1, a2, a3, a4, a5) \
9806fbba JM	384	int _v1tmp = (int) (a5); \
	385	LOAD_ARGS_4 (a1, a2, a3, a4) \
	386	register int _v1 asm ("v1") = _v1tmp;
ba023f01	387	#define ASM_ARGS_5 ASM_ARGS_4, "r" (_v1)
62749187	388	#define LOAD_ARGS_6(a1, a2, a3, a4, a5, a6) \
9806fbba JM	389	int _v2tmp = (int) (a6); \
	390	LOAD_ARGS_5 (a1, a2, a3, a4, a5) \
	391	register int _v2 asm ("v2") = _v2tmp;
62749187	392	#define ASM_ARGS_6 ASM_ARGS_5, "r" (_v2)
25593dca JM	393	#ifndef __thumb__
	394	# define LOAD_ARGS_7(a1, a2, a3, a4, a5, a6, a7) \
	395	int _v3tmp = (int) (a7); \
	396	LOAD_ARGS_6 (a1, a2, a3, a4, a5, a6) \
9806fbba	397	register int _v3 asm ("v3") = _v3tmp;
25593dca JM	398	# define ASM_ARGS_7 ASM_ARGS_6, "r" (_v3)
	399	#endif
	400
	401	/* For EABI, non-constant syscalls are actually pretty easy... */
	402	#undef INTERNAL_SYSCALL_NCS
	403	#define INTERNAL_SYSCALL_NCS(number, err, nr, args...) \
	404	INTERNAL_SYSCALL_RAW (number, err, nr, args)
02a9f771	405
e0ebc3b2	406	#endif /* __ASSEMBLER__ */
8d2485ed	407
908afa83 DJ	408	/* Pointer mangling is not yet supported for ARM. */
	409	#define PTR_MANGLE(var) (void) (var)
	410	#define PTR_DEMANGLE(var) (void) (var)
	411
8d2485ed	412	#endif /* linux/arm/sysdep.h */