[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					\
	it	cc;					\
	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:						\
	rsb	r0, r0, #0;					\
	LDST_PCREL(str, r0, r1, C_SYMBOL_NAME(rtld_errno));	\
	mvn	r0, #0;						\
	DO_RET(lr)
# 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	59	#undef PSEUDO
63cc0e75 RH	60	#define PSEUDO(name, syscall_name, args) \
	61	.text; \
	62	ENTRY (name); \
	63	DO_CALL (syscall_name, args); \
	64	cmn r0, $4096;
	65
	66	#define PSEUDO_RET \
6ccd0107	67	it cc; \
63cc0e75 RH	68	RETINSTR(cc, lr); \
63cc0e75 RH	69	b PLTJMP(SYSCALL_ERROR)
63ac74aa UD	70	#undef ret
63ac74aa UD	71	#define ret PSEUDO_RET
8d2485ed UD	72
8d2485ed UD	73	#undef PSEUDO_END
63cc0e75 RH	74	#define PSEUDO_END(name) \
63cc0e75 RH	75	SYSCALL_ERROR_HANDLER; \
8d2485ed UD	76	END (name)
8d2485ed UD	77
98f7320f	78	#undef PSEUDO_NOERRNO
63cc0e75 RH	79	#define PSEUDO_NOERRNO(name, syscall_name, args) \
	80	.text; \
	81	ENTRY (name); \
	82	DO_CALL (syscall_name, args);
98f7320f	83
63cc0e75 RH	84	#define PSEUDO_RET_NOERRNO \
63cc0e75 RH	85	DO_RET (lr);
44acff5d	86
98f7320f UD	87	#undef ret_NOERRNO
	88	#define ret_NOERRNO PSEUDO_RET_NOERRNO
	89
	90	#undef PSEUDO_END_NOERRNO
63cc0e75	91	#define PSEUDO_END_NOERRNO(name) \
98f7320f UD	92	END (name)
98f7320f UD	93
ae53e7a7 UD	94	/* The function has to return the error code. */
ae53e7a7 UD	95	#undef PSEUDO_ERRVAL
63cc0e75 RH	96	#define PSEUDO_ERRVAL(name, syscall_name, args) \
	97	.text; \
	98	ENTRY (name) \
	99	DO_CALL (syscall_name, args); \
	100	rsb r0, r0, #0
ae53e7a7 UD	101
ae53e7a7 UD	102	#undef PSEUDO_END_ERRVAL
63cc0e75	103	#define PSEUDO_END_ERRVAL(name) \
ae53e7a7 UD	104	END (name)
	105
	106	#define ret_ERRVAL PSEUDO_RET_NOERRNO
	107
2f0910ca UD	108	#if NOT_IN_libc
2f0910ca UD	109	# define SYSCALL_ERROR __local_syscall_error
02a9f771 DJ	110	# if RTLD_PRIVATE_ERRNO
	111	# define SYSCALL_ERROR_HANDLER \
	112	__local_syscall_error: \
cd24e113 RH	113	rsb r0, r0, #0; \
	114	LDST_PCREL(str, r0, r1, C_SYMBOL_NAME(rtld_errno)); \
	115	mvn r0, #0; \
	116	DO_RET(lr)
02a9f771	117	# else
01b32e73 TS	118	# if defined(__ARM_ARCH_4T__) && defined(__THUMB_INTERWORK__)
	119	# define POP_PC \
	120	ldr lr, [sp], #4; \
	121	cfi_adjust_cfa_offset (-4); \
	122	cfi_restore (lr); \
	123	bx lr
	124	# else
	125	# define POP_PC \
	126	ldr pc, [sp], #4
	127	# endif
02a9f771	128	# define SYSCALL_ERROR_HANDLER \
2f0910ca UD	129	__local_syscall_error: \
2f0910ca UD	130	str lr, [sp, #-4]!; \
01b32e73 TS	131	cfi_adjust_cfa_offset (4); \
01b32e73 TS	132	cfi_rel_offset (lr, 0); \
2f0910ca	133	str r0, [sp, #-4]!; \
01b32e73	134	cfi_adjust_cfa_offset (4); \
2f0910ca UD	135	bl PLTJMP(C_SYMBOL_NAME(__errno_location)); \
2f0910ca UD	136	ldr r1, [sp], #4; \
01b32e73	137	cfi_adjust_cfa_offset (-4); \
2f0910ca UD	138	rsb r1, r1, #0; \
	139	str r1, [r0]; \
	140	mvn r0, #0; \
b2b2415f	141	POP_PC;
02a9f771	142	# endif
2f0910ca UD	143	#else
	144	# define SYSCALL_ERROR_HANDLER /* Nothing here; code in sysdep.S is used. */
	145	# define SYSCALL_ERROR __syscall_error
	146	#endif
ff550b1f	147
25593dca JM	148	/* The ARM EABI user interface passes the syscall number in r7, instead
	149	of in the swi. This is more efficient, because the kernel does not need
	150	to fetch the swi from memory to find out the number; which can be painful
	151	with separate I-cache and D-cache. Make sure to use 0 for the SWI
	152	argument; otherwise the (optional) compatibility code for APCS binaries
	153	may be invoked. */
	154
ff550b1f	155	/* Linux takes system call args in registers:
ff550b1f UD	156	arg 1 r0
	157	arg 2 r1
	158	arg 3 r2
	159	arg 4 r3
	160	arg 5 r4 (this is different from the APCS convention)
62749187 UD	161	arg 6 r5
62749187 UD	162	arg 7 r6
ff550b1f UD	163
	164	The compiler is going to form a call by coming here, through PSEUDO, with
	165	arguments
	166	syscall number in the DO_CALL macro
	167	arg 1 r0
	168	arg 2 r1
	169	arg 3 r2
	170	arg 4 r3
	171	arg 5 [sp]
62749187 UD	172	arg 6 [sp+4]
62749187 UD	173	arg 7 [sp+8]
ff550b1f	174
62749187 UD	175	We need to shuffle values between R4..R6 and the stack so that the
	176	caller's v1..v3 and stack frame are not corrupted, and the kernel
	177	sees the right arguments.
ff550b1f UD	178
ff550b1f UD	179	*/
8d2485ed	180
25593dca JM	181	/* We must save and restore r7 (call-saved) for the syscall number.
	182	We never make function calls from inside here (only potentially
	183	signal handlers), so we do not bother with doubleword alignment.
	184
	185	Just like the APCS syscall convention, the EABI syscall convention uses
	186	r0 through r6 for up to seven syscall arguments. None are ever passed to
	187	the kernel on the stack, although incoming arguments are on the stack for
	188	syscalls with five or more arguments.
	189
	190	The assembler will convert the literal pool load to a move for most
	191	syscalls. */
	192
8d2485ed	193	#undef DO_CALL
63cc0e75 RH	194	#define DO_CALL(syscall_name, args) \
	195	DOARGS_##args; \
	196	ldr r7, =SYS_ify (syscall_name); \
	197	swi 0x0; \
	198	UNDOARGS_##args
ff550b1f	199
25593dca	200	#undef DOARGS_0
63cc0e75 RH	201	#define DOARGS_0 \
	202	.fnstart; \
	203	str r7, [sp, #-4]!; \
	204	cfi_adjust_cfa_offset (4); \
	205	cfi_rel_offset (r7, 0); \
	206	.save { r7 }
25593dca JM	207	#undef DOARGS_1
	208	#define DOARGS_1 DOARGS_0
	209	#undef DOARGS_2
	210	#define DOARGS_2 DOARGS_0
	211	#undef DOARGS_3
	212	#define DOARGS_3 DOARGS_0
	213	#undef DOARGS_4
	214	#define DOARGS_4 DOARGS_0
	215	#undef DOARGS_5
63cc0e75 RH	216	#define DOARGS_5 \
	217	.fnstart; \
	218	stmfd sp!, {r4, r7}; \
	219	cfi_adjust_cfa_offset (8); \
	220	cfi_rel_offset (r4, 0); \
	221	cfi_rel_offset (r7, 4); \
	222	.save { r4, r7 }; \
	223	ldr r4, [sp, #8]
25593dca	224	#undef DOARGS_6
63cc0e75 RH	225	#define DOARGS_6 \
	226	.fnstart; \
	227	mov ip, sp; \
	228	stmfd sp!, {r4, r5, r7}; \
	229	cfi_adjust_cfa_offset (12); \
	230	cfi_rel_offset (r4, 0); \
	231	cfi_rel_offset (r5, 4); \
	232	cfi_rel_offset (r7, 8); \
	233	.save { r4, r5, r7 }; \
	234	ldmia ip, {r4, r5}
25593dca	235	#undef DOARGS_7
63cc0e75 RH	236	#define DOARGS_7 \
	237	.fnstart; \
	238	mov ip, sp; \
	239	stmfd sp!, {r4, r5, r6, r7}; \
	240	cfi_adjust_cfa_offset (16); \
	241	cfi_rel_offset (r4, 0); \
	242	cfi_rel_offset (r5, 4); \
	243	cfi_rel_offset (r6, 8); \
	244	cfi_rel_offset (r7, 12); \
	245	.save { r4, r5, r6, r7 }; \
	246	ldmia ip, {r4, r5, r6}
ff550b1f	247
25593dca	248	#undef UNDOARGS_0
63cc0e75 RH	249	#define UNDOARGS_0 \
	250	ldr r7, [sp], #4; \
	251	cfi_adjust_cfa_offset (-4); \
	252	cfi_restore (r7); \
	253	.fnend
25593dca JM	254	#undef UNDOARGS_1
	255	#define UNDOARGS_1 UNDOARGS_0
	256	#undef UNDOARGS_2
	257	#define UNDOARGS_2 UNDOARGS_0
	258	#undef UNDOARGS_3
	259	#define UNDOARGS_3 UNDOARGS_0
	260	#undef UNDOARGS_4
	261	#define UNDOARGS_4 UNDOARGS_0
	262	#undef UNDOARGS_5
63cc0e75 RH	263	#define UNDOARGS_5 \
	264	ldmfd sp!, {r4, r7}; \
	265	cfi_adjust_cfa_offset (-8); \
	266	cfi_restore (r4); \
	267	cfi_restore (r7); \
	268	.fnend
25593dca	269	#undef UNDOARGS_6
63cc0e75 RH	270	#define UNDOARGS_6 \
	271	ldmfd sp!, {r4, r5, r7}; \
	272	cfi_adjust_cfa_offset (-12); \
	273	cfi_restore (r4); \
	274	cfi_restore (r5); \
	275	cfi_restore (r7); \
	276	.fnend
25593dca	277	#undef UNDOARGS_7
63cc0e75 RH	278	#define UNDOARGS_7 \
	279	ldmfd sp!, {r4, r5, r6, r7}; \
	280	cfi_adjust_cfa_offset (-16); \
	281	cfi_restore (r4); \
	282	cfi_restore (r5); \
	283	cfi_restore (r6); \
	284	cfi_restore (r7); \
	285	.fnend
8d2485ed	286
ba023f01 UD	287	#else /* not __ASSEMBLER__ */
	288
	289	/* Define a macro which expands into the inline wrapper code for a system
	290	call. */
	291	#undef INLINE_SYSCALL
2f0910ca	292	#define INLINE_SYSCALL(name, nr, args...) \
114e7d50 UD	293	({ unsigned int _sys_result = INTERNAL_SYSCALL (name, , nr, args); \
114e7d50 UD	294	if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (_sys_result, ), 0)) \
2f0910ca	295	{ \
114e7d50	296	__set_errno (INTERNAL_SYSCALL_ERRNO (_sys_result, )); \
2f0910ca UD	297	_sys_result = (unsigned int) -1; \
	298	} \
	299	(int) _sys_result; })
	300
aeeec7fb UD	301	#undef INTERNAL_SYSCALL_DECL
	302	#define INTERNAL_SYSCALL_DECL(err) do { } while (0)
	303
25593dca JM	304	#if defined(__thumb__)
	305	/* We can not expose the use of r7 to the compiler. GCC (as
	306	of 4.5) uses r7 as the hard frame pointer for Thumb - although
	307	for Thumb-2 it isn't obviously a better choice than r11.
	308	And GCC does not support asms that conflict with the frame
	309	pointer.
	310
	311	This would be easier if syscall numbers never exceeded 255,
	312	but they do. For the moment the LOAD_ARGS_7 is sacrificed.
	313	We can't use push/pop inside the asm because that breaks
	314	unwinding (i.e. thread cancellation) for this frame. We can't
	315	locally save and restore r7, because we do not know if this
	316	function uses r7 or if it is our caller's r7; if it is our caller's,
	317	then unwinding will fail higher up the stack. So we move the
	318	syscall out of line and provide its own unwind information. */
	319	# undef INTERNAL_SYSCALL_RAW
	320	# define INTERNAL_SYSCALL_RAW(name, err, nr, args...) \
	321	({ \
	322	register int _a1 asm ("a1"); \
	323	int _nametmp = name; \
	324	LOAD_ARGS_##nr (args) \
	325	register int _name asm ("ip") = _nametmp; \
	326	asm volatile ("bl __libc_do_syscall" \
	327	: "=r" (_a1) \
	328	: "r" (_name) ASM_ARGS_##nr \
	329	: "memory", "lr"); \
	330	_a1; })
	331	#else /* ARM */
	332	# undef INTERNAL_SYSCALL_RAW
	333	# define INTERNAL_SYSCALL_RAW(name, err, nr, args...) \
	334	({ \
	335	register int _a1 asm ("r0"), _nr asm ("r7"); \
ba023f01	336	LOAD_ARGS_##nr (args) \
25593dca JM	337	_nr = name; \
25593dca JM	338	asm volatile ("swi 0x0 @ syscall " #name \
ba023f01	339	: "=r" (_a1) \
25593dca	340	: "r" (_nr) ASM_ARGS_##nr \
cf666e4b	341	: "memory"); \
25593dca JM	342	_a1; })
25593dca JM	343	#endif
ba023f01	344
485a9bb9 DJ	345	#undef INTERNAL_SYSCALL
	346	#define INTERNAL_SYSCALL(name, err, nr, args...) \
	347	INTERNAL_SYSCALL_RAW(SYS_ify(name), err, nr, args)
	348
	349	#undef INTERNAL_SYSCALL_ARM
	350	#define INTERNAL_SYSCALL_ARM(name, err, nr, args...) \
	351	INTERNAL_SYSCALL_RAW(__ARM_NR_##name, err, nr, args)
	352
2f0910ca	353	#undef INTERNAL_SYSCALL_ERROR_P
aeeec7fb UD	354	#define INTERNAL_SYSCALL_ERROR_P(val, err) \
aeeec7fb UD	355	((unsigned int) (val) >= 0xfffff001u)
2f0910ca UD	356
2f0910ca UD	357	#undef INTERNAL_SYSCALL_ERRNO
aeeec7fb	358	#define INTERNAL_SYSCALL_ERRNO(val, err) (-(val))
2f0910ca	359
ba023f01 UD	360	#define LOAD_ARGS_0()
	361	#define ASM_ARGS_0
	362	#define LOAD_ARGS_1(a1) \
9806fbba JM	363	int _a1tmp = (int) (a1); \
	364	LOAD_ARGS_0 () \
	365	_a1 = _a1tmp;
ba023f01 UD	366	#define ASM_ARGS_1 ASM_ARGS_0, "r" (_a1)
ba023f01 UD	367	#define LOAD_ARGS_2(a1, a2) \
9806fbba JM	368	int _a2tmp = (int) (a2); \
	369	LOAD_ARGS_1 (a1) \
	370	register int _a2 asm ("a2") = _a2tmp;
ba023f01 UD	371	#define ASM_ARGS_2 ASM_ARGS_1, "r" (_a2)
ba023f01 UD	372	#define LOAD_ARGS_3(a1, a2, a3) \
9806fbba JM	373	int _a3tmp = (int) (a3); \
	374	LOAD_ARGS_2 (a1, a2) \
	375	register int _a3 asm ("a3") = _a3tmp;
ba023f01 UD	376	#define ASM_ARGS_3 ASM_ARGS_2, "r" (_a3)
ba023f01 UD	377	#define LOAD_ARGS_4(a1, a2, a3, a4) \
9806fbba JM	378	int _a4tmp = (int) (a4); \
	379	LOAD_ARGS_3 (a1, a2, a3) \
	380	register int _a4 asm ("a4") = _a4tmp;
ba023f01 UD	381	#define ASM_ARGS_4 ASM_ARGS_3, "r" (_a4)
ba023f01 UD	382	#define LOAD_ARGS_5(a1, a2, a3, a4, a5) \
9806fbba JM	383	int _v1tmp = (int) (a5); \
	384	LOAD_ARGS_4 (a1, a2, a3, a4) \
	385	register int _v1 asm ("v1") = _v1tmp;
ba023f01	386	#define ASM_ARGS_5 ASM_ARGS_4, "r" (_v1)
62749187	387	#define LOAD_ARGS_6(a1, a2, a3, a4, a5, a6) \
9806fbba JM	388	int _v2tmp = (int) (a6); \
	389	LOAD_ARGS_5 (a1, a2, a3, a4, a5) \
	390	register int _v2 asm ("v2") = _v2tmp;
62749187	391	#define ASM_ARGS_6 ASM_ARGS_5, "r" (_v2)
25593dca JM	392	#ifndef __thumb__
	393	# define LOAD_ARGS_7(a1, a2, a3, a4, a5, a6, a7) \
	394	int _v3tmp = (int) (a7); \
	395	LOAD_ARGS_6 (a1, a2, a3, a4, a5, a6) \
9806fbba	396	register int _v3 asm ("v3") = _v3tmp;
25593dca JM	397	# define ASM_ARGS_7 ASM_ARGS_6, "r" (_v3)
	398	#endif
	399
	400	/* For EABI, non-constant syscalls are actually pretty easy... */
	401	#undef INTERNAL_SYSCALL_NCS
	402	#define INTERNAL_SYSCALL_NCS(number, err, nr, args...) \
	403	INTERNAL_SYSCALL_RAW (number, err, nr, args)
02a9f771	404
e0ebc3b2	405	#endif /* __ASSEMBLER__ */
8d2485ed	406
908afa83 DJ	407	/* Pointer mangling is not yet supported for ARM. */
	408	#define PTR_MANGLE(var) (void) (var)
	409	#define PTR_DEMANGLE(var) (void) (var)
	410
8d2485ed	411	#endif /* linux/arm/sysdep.h */