path: root/sysdeps/unix/sysv/linux/hppa/sysdep.h

/* Assembler macros for PA-RISC.
   Copyright (C) 1999, 2001, 2002, 2003 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper, <drepper@cygnus.com>, August 1999.
   Linux/PA-RISC changes by Philipp Rumpf, <prumpf@tux.org>, March 2000.

   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.  */

#include <asm/unistd.h>
#include <sysdeps/generic/sysdep.h>
#include <sys/syscall.h>
#include "config.h"

#ifndef ASM_LINE_SEP
# define ASM_LINE_SEP ;
#endif

#undef SYS_ify
#define SYS_ify(syscall_name)	(__NR_##syscall_name)

#ifdef PIC
/* WARNING: CANNOT BE USED IN A NOP! */
# define STW_PIC stw %r19, -32(%sr0, %sp) ASM_LINE_SEP
# define LDW_PIC ldw -32(%sr0, %sp), %r19 ASM_LINE_SEP
# define STW_ASM_PIC	"       copy %%r19, %%r4\n"
# define LDW_ASM_PIC	"       copy %%r4, %%r19\n"
# define USING_GR4	"%r4",
#else
# define STW_PIC ASM_LINE_SEP
# define LDW_PIC ASM_LINE_SEP
# define STW_ASM_PIC	" \n"
# define LDW_ASM_PIC	" \n"
# define USING_GR4
#endif

#ifdef __ASSEMBLER__

/* Syntactic details of assembler.  */

#define ALIGNARG(log2) log2

/* 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

/* ELF-like local names start with `.L'.  */
#undef L
#define L(name)	.L##name

/* 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 %eax
   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.  */

/* We don't want the label for the error handle to be global when we define
   it here.  */
#ifdef PIC
# define SYSCALL_ERROR_LABEL 0f
#else
# define SYSCALL_ERROR_LABEL syscall_error
#endif

/* Define an entry point visible from C.

   There is currently a bug in gdb which prevents us from specifying
   incomplete stabs information.  Fake some entries here which specify
   the current source file.  */
#define	ENTRY(name)						\
	.text					ASM_LINE_SEP	\
	.export C_SYMBOL_NAME(name)		ASM_LINE_SEP	\
	.type	C_SYMBOL_NAME(name),@function	ASM_LINE_SEP	\
	C_LABEL(name)				ASM_LINE_SEP	\
	CALL_MCOUNT				ASM_LINE_SEP

#undef	END
#define END(name)							\
1:							ASM_LINE_SEP	\
.size	C_SYMBOL_NAME(name),1b-C_SYMBOL_NAME(name)	ASM_LINE_SEP

/* If compiled for profiling, call `mcount' at the start of each function.  */
/* No, don't bother.  gcc will put the call in for us.  */
#define CALL_MCOUNT		/* Do nothing.  */

/* syscall wrappers consist of
	#include <sysdep.h>
	PSEUDO(...)
	ret
	PSEUDO_END(...)

   which means
	ENTRY(name)
	DO_CALL(...)
	nop
	bv 0(2)
	nop
*/

#define	PSEUDO(name, syscall_name, args)			\
  ENTRY (name)							\
  DO_CALL(syscall_name, args)			ASM_LINE_SEP	\
  nop						ASM_LINE_SEP

#define ret \
	/* Return value set by ERRNO code */	ASM_LINE_SEP	\
	bv 0(2)					ASM_LINE_SEP	\
	nop					ASM_LINE_SEP

#undef	PSEUDO_END
#define	PSEUDO_END(name)					\
  END (name)

/* We don't set the errno on the return from the syscall */
#define	PSEUDO_NOERRNO(name, syscall_name, args)		\
  ENTRY (name)							\
  DO_CALL_NOERRNO(syscall_name, args)		ASM_LINE_SEP	\
  nop						ASM_LINE_SEP

#define ret_NOERRNO ret

#undef	PSEUDO_END_NOERRNO
#define	PSEUDO_END_NOERRNO(name)				\
  END (name)

/* This has to return the error value */
#undef  PSEUDO_ERRVAL
#define PSEUDO_ERRVAL(name, syscall_name, args)			\
	ENTRY(name)						\
	DO_CALL_ERRVAL(syscall_name, args)	ASM_LINE_SEP	\
	nop					ASM_LINE_SEP

#define ret_ERRVAL ret

#undef	PSEUDO_END_ERRVAL
#define PSEUDO_END_ERRVAL(name)					\
	END(name)

#undef JUMPTARGET
#define JUMPTARGET(name)	name
#define SYSCALL_PIC_SETUP	/* Nothing.  */


/* All the syscall assembly macros rely on finding the approriate
   SYSCALL_ERROR_LABEL or rather HANDLER. */

/* int * __errno_location(void) so you have to store your value
   into the return address! */
#define DEFAULT_SYSCALL_ERROR_HANDLER 			\
	.import __errno_location,code	ASM_LINE_SEP	\
	/* branch to errno handler */	ASM_LINE_SEP	\
	bl __errno_location,%rp		ASM_LINE_SEP

/* Here are the myriad of configuration options that the above can
   work for... what we've done is provide the framework for future
   changes if required to each section */

#ifdef PIC
# if RTLD_PRIVATE_ERRNO
#  define SYSCALL_ERROR_HANDLER DEFAULT_SYSCALL_ERROR_HANDLER
# else /* !RTLD_PRIVATE_ERRNO */
#  if defined _LIBC_REENTRANT
#   define SYSCALL_ERROR_HANDLER DEFAULT_SYSCALL_ERROR_HANDLER
#  else /* !_LIBC_REENTRANT */
#   define SYSCALL_ERROR_HANDLER DEFAULT_SYSCALL_ERROR_HANDLER
#  endif /* _LIBC_REENTRANT */
# endif /* RTLD_PRIVATE_ERRNO */
#else
# ifndef _LIBC_REENTRANT
#  define SYSCALL_ERROR_HANDLER DEFAULT_SYSCALL_ERROR_HANDLER
# else
#  define SYSCALL_ERROR_HANDLER DEFAULT_SYSCALL_ERROR_HANDLER
# endif
#endif


/* Linux takes system call arguments in registers:
	syscall number	gr20
	arg 1		gr26
	arg 2		gr25
	arg 3		gr24
	arg 4		gr23
	arg 5		gr22
	arg 6		gr21

   The compiler calls us by the C convention:
	syscall number	in the DO_CALL macro
	arg 1		gr26
	arg 2		gr25
	arg 3		gr24
	arg 4		gr23
	arg 5		-52(gr30)
	arg 6		-56(gr30)

   gr22 and gr21 are caller-saves, so we can just load the arguments
   there and generally be happy. */

/* the cmpb...no_error code below inside DO_CALL
 * is intended to mimic the if (__sys_res...)
 * code inside INLINE_SYSCALL
 */

#undef	DO_CALL
#define DO_CALL(syscall_name, args)				\
	DOARGS_##args				ASM_LINE_SEP	\
	STW_PIC					ASM_LINE_SEP	\
	/* Do syscall, delay loads # */		ASM_LINE_SEP	\
	ble  0x100(%sr2,%r0)			ASM_LINE_SEP	\
	ldi SYS_ify (syscall_name), %r20	ASM_LINE_SEP	\
	ldi -0x1000,%r1				ASM_LINE_SEP	\
	cmpb,>>=,n %r1,%ret0,0f			ASM_LINE_SEP	\
	/* save rp or we get lost */		ASM_LINE_SEP	\
	stw %rp, -20(%sr0,%sp)			ASM_LINE_SEP	\
	/* Restore r19 from frame */		ASM_LINE_SEP	\
	LDW_PIC					ASM_LINE_SEP	\
	stw %ret0, -24(%sr0,%sp)		ASM_LINE_SEP	\
	SYSCALL_ERROR_HANDLER			ASM_LINE_SEP	\
	/* create frame */			ASM_LINE_SEP	\
	ldo 64(%sp), %sp			ASM_LINE_SEP	\
	ldo -64(%sp), %sp			ASM_LINE_SEP	\
	/* OPTIMIZE: Don't reload r19 */	ASM_LINE_SEP	\
	/* do a -1*syscall_ret0 */		ASM_LINE_SEP	\
	ldw -24(%sr0,%sp), %r26			ASM_LINE_SEP	\
	sub %r0, %r26, %r26			ASM_LINE_SEP	\
	/* Store into errno location */		ASM_LINE_SEP	\
	stw %r26, 0(%sr0,%ret0)			ASM_LINE_SEP	\
	/* return -1 as error */		ASM_LINE_SEP	\
	ldo -1(%r0), %ret0			ASM_LINE_SEP	\
	ldw -20(%sr0,%sp), %rp			ASM_LINE_SEP	\
0:						ASM_LINE_SEP	\
	UNDOARGS_##args				ASM_LINE_SEP

/* We do nothing with the return, except hand it back to someone else */
#undef  DO_CALL_NOERRNO
#define DO_CALL_NOERRNO(syscall_name, args)			\
	DOARGS_##args                                           \
	/* No need to store r19 */		ASM_LINE_SEP	\
	ble  0x100(%sr2,%r0)                    ASM_LINE_SEP    \
	ldi SYS_ify (syscall_name), %r20        ASM_LINE_SEP    \
	/* Caller will restore r19 */		ASM_LINE_SEP	\
	UNDOARGS_##args

/* Here, we return the ERRVAL in assembly, note we don't call the
   error handler function, but we do 'negate' the return _IF_
   it's an error. Not sure if this is the right semantic. */

#undef	DO_CALL_ERRVAL
#define DO_CALL_ERRVAL(syscall_name, args)			\
	DOARGS_##args				ASM_LINE_SEP	\
	/* No need to store r19 */		ASM_LINE_SEP	\
	ble  0x100(%sr2,%r0)			ASM_LINE_SEP	\
	ldi SYS_ify (syscall_name), %r20	ASM_LINE_SEP	\
	/* Caller will restore r19 */		ASM_LINE_SEP	\
	ldi -0x1000,%r1				ASM_LINE_SEP	\
	cmpb,>>=,n %r1,%ret0,0f			ASM_LINE_SEP	\
	sub %r0, %ret0, %ret0			ASM_LINE_SEP	\
0:						ASM_LINE_SEP	\
	UNDOARGS_##args				ASM_LINE_SEP

#define DOARGS_0 /* nothing */
#define DOARGS_1 /* nothing */
#define DOARGS_2 /* nothing */
#define DOARGS_3 /* nothing */
#define DOARGS_4 /* nothing */
#define DOARGS_5 ldw -52(%r30), %r22		ASM_LINE_SEP
#define DOARGS_6 ldw -52(%r30), %r22		ASM_LINE_SEP	\
		 ldw -56(%r30), %r21		ASM_LINE_SEP


#define UNDOARGS_0 /* nothing */
#define UNDOARGS_1 /* nothing */
#define UNDOARGS_2 /* nothing */
#define UNDOARGS_3 /* nothing */
#define UNDOARGS_4 /* nothing */
#define UNDOARGS_5 /* nothing */
#define UNDOARGS_6 /* nothing */

#else

/* GCC has to be warned that a syscall may clobber all the ABI
   registers listed as "caller-saves", see page 8, Table 2
   in section 2.2.6 of the PA-RISC RUN-TIME architecture
   document. However! r28 is the result and will conflict with
   the clobber list so it is left out. Also the input arguments
   registers r20 -> r26 will conflict with the list so they
   are treated specially. Although r19 is clobbered by the syscall
   we cannot say this because it would violate ABI, thus we say
   r4 is clobbered and use that register to save/restore r19
   across the syscall. */

#define CALL_CLOB_REGS	"%r1", "%r2", USING_GR4 \
		 	"%r20", "%r29", "%r31"

#undef INLINE_SYSCALL
#define INLINE_SYSCALL(name, nr, args...)	({			\
	long __sys_res;							\
	{								\
		register unsigned long __res asm("r28");		\
		LOAD_ARGS_##nr(args)					\
		/* FIXME: HACK stw/ldw r19 around syscall */		\
		asm volatile(						\
			STW_ASM_PIC					\
			"	ble  0x100(%%sr2, %%r0)\n"		\
			"	ldi %1, %%r20\n"			\
			LDW_ASM_PIC					\
			: "=r" (__res)					\
			: "i" (SYS_ify(name)) ASM_ARGS_##nr		\
			: CALL_CLOB_REGS CLOB_ARGS_##nr			\
		);							\
		__sys_res = (long)__res;				\
	}								\
	if ( (unsigned long)__sys_res >= (unsigned long)-4095 ){	\
		__set_errno(-__sys_res);				\
		__sys_res = -1;						\
	}								\
	__sys_res;							\
})

/* INTERNAL_SYSCALL_DECL - Allows us to setup some function static
   value to use within the context of the syscall
   INTERNAL_SYSCALL_ERROR_P - Returns 0 if it wasn't an error, 1 otherwise
   You are allowed to use the syscall result (val) and the DECL error variable
   to determine what went wrong.
   INTERLAL_SYSCALL_ERRNO - Munges the val/err pair into the error number.
   In our case we just flip the sign. */

#undef INTERNAL_SYSCALL_DECL
#define INTERNAL_SYSCALL_DECL(err) do { } while (0)

/* Equivalent to  (val < 0)&&(val > -4095) which is what we want */
#undef INTERNAL_SYSCALL_ERROR_P
#define INTERNAL_SYSCALL_ERROR_P(val, err) \
	((unsigned long)val >= (unsigned long)-4095)

#undef INTERNAL_SYSCALL_ERRNO
#define INTERNAL_SYSCALL_ERRNO(val, err) (-(val))

/* Similar to INLINE_SYSCALL but we don't set errno */
#undef INTERNAL_SYSCALL
#define INTERNAL_SYSCALL(name, err, nr, args...) 		\
({								\
	long __sys_res;						\
	{							\
		register unsigned long __res asm("r28");	\
		LOAD_ARGS_##nr(args)				\
		/* FIXME: HACK stw/ldw r19 around syscall */	\
		asm volatile(					\
			STW_ASM_PIC				\
			"	ble  0x100(%%sr2, %%r0)\n"	\
			"	ldi %1, %%r20\n"		\
			LDW_ASM_PIC				\
			: "=r" (__res)				\
			: "i" (SYS_ify(name)) ASM_ARGS_##nr	\
			 );					\
			: CALL_CLOB_REGS CLOB_ARGS_##nr		\
		);						\
		__sys_res = (long)__res;			\
	}							\
	__sys_res;						\
 })

#define LOAD_ARGS_0()
#define LOAD_ARGS_1(r26)					\
	register unsigned long __r26 __asm__("r26") = (unsigned long)r26;     \
	LOAD_ARGS_0()
#define LOAD_ARGS_2(r26,r25)					\
	register unsigned long __r25 __asm__("r25") = (unsigned long)r25;     \
	LOAD_ARGS_1(r26)
#define LOAD_ARGS_3(r26,r25,r24)				\
	register unsigned long __r24 __asm__("r24") = (unsigned long)r24;     \
	LOAD_ARGS_2(r26,r25)
#define LOAD_ARGS_4(r26,r25,r24,r23)				\
	register unsigned long __r23 __asm__("r23") = (unsigned long)r23;     \
	LOAD_ARGS_3(r26,r25,r24)
#define LOAD_ARGS_5(r26,r25,r24,r23,r22)			\
	register unsigned long __r22 __asm__("r22") = (unsigned long)r22;     \
	LOAD_ARGS_4(r26,r25,r24,r23)
#define LOAD_ARGS_6(r26,r25,r24,r23,r22,r21)			\
	register unsigned long __r21 __asm__("r21") = (unsigned long)r21;     \
	LOAD_ARGS_5(r26,r25,r24,r23,r22)

/* Even with zero args we use r20 for the syscall number */
#define ASM_ARGS_0
#define ASM_ARGS_1 ASM_ARGS_0, "r" (__r26)
#define ASM_ARGS_2 ASM_ARGS_1, "r" (__r25)
#define ASM_ARGS_3 ASM_ARGS_2, "r" (__r24)
#define ASM_ARGS_4 ASM_ARGS_3, "r" (__r23)
#define ASM_ARGS_5 ASM_ARGS_4, "r" (__r22)
#define ASM_ARGS_6 ASM_ARGS_5, "r" (__r21)

/* The registers not listed as inputs but clobbered */
#define CLOB_ARGS_6
#define CLOB_ARGS_5 CLOB_ARGS_6, "%r21"
#define CLOB_ARGS_4 CLOB_ARGS_5, "%r22"
#define CLOB_ARGS_3 CLOB_ARGS_4, "%r23"
#define CLOB_ARGS_2 CLOB_ARGS_3, "%r24"
#define CLOB_ARGS_1 CLOB_ARGS_2, "%r25"
#define CLOB_ARGS_0 CLOB_ARGS_1, "%r26"

#endif	/* __ASSEMBLER__ */