/*      $OpenBSD: SYS.h,v 1.18 2023/12/11 22:24:15 kettenis Exp $       */
/*      $NetBSD: SYS.h,v 1.4 1996/10/17 03:03:53 cgd Exp $      */

/*
 * Copyright (c) 1994, 1995 Carnegie-Mellon University.
 * All rights reserved.
 *
 * Author: Chris G. Demetriou
 * 
 * Permission to use, copy, modify and distribute this software and
 * its documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 * 
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 
 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 * 
 * Carnegie Mellon requests users of this software to return to
 *
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 *
 * any improvements or extensions that they make and grant Carnegie the
 * rights to redistribute these changes.
 */

#include <machine/asm.h>
#include <machine/pal.h>                /* for PAL_rdunique */
#include <sys/syscall.h>


/* offsetof(struct tib, tib_errno) - offsetof(struct tib, __tib_tcb) */
#define TCB_OFFSET_ERRNO        (-12)

/*
 * We define a hidden alias with the prefix "_libc_" for each global symbol
 * that may be used internally.  By referencing _libc_x instead of x, other
 * parts of libc prevent overriding by the application and avoid unnecessary
 * relocations.
 */
#define _HIDDEN(x)              _libc_##x
#define _HIDDEN_ALIAS(x,y)                      \
        STRONG_ALIAS(_HIDDEN(x),y);             \
        .hidden _HIDDEN(x)
#define _HIDDEN_FALIAS(x,y)                     \
        _HIDDEN_ALIAS(x,y);                     \
        .type _HIDDEN(x),@function

/*
 * END() uses the alpha .end pseudo-op which requires a matching .ent,
 * so here's a short hand for just doing .size
 */
#define _END(x)         .size x, . - x

#define PINSYSCALL(sysno, label)                                        \
        .pushsection .openbsd.syscalls,"",@progbits;                    \
        .p2align 2;                                                     \
        .long label;                                                    \
        .long sysno;                                                    \
        .popsection;

/*
 * For functions implemented in ASM that aren't syscalls.
 *   END_STRONG(x)      Like DEF_STRONG() in C; for standard/reserved C names
 *   END_WEAK(x)        Like DEF_WEAK() in C; for non-ISO C names
 */
#define END_STRONG(x)   END(x); _HIDDEN_FALIAS(x,x);            \
                        _END(_HIDDEN(x))
#define END_WEAK(x)     END_STRONG(x); .weak x

#define CALLSYS_NOERROR(name)                                   \
        ldiq    v0, ___CONCAT(SYS_,name);                       \
97:     call_pal PAL_OSF1_callsys;                              \
        PINSYSCALL(___CONCAT(SYS_,name), 97b)

#define CALLSYS_ERROR(name)                                     \
        CALLSYS_NOERROR(name);                                  \
        beq     a3, LLABEL(name,1);                             \
        mov     v0, t0;                                         \
        call_pal PAL_rdunique;                                  \
        stl     t0, TCB_OFFSET_ERRNO(v0);                       \
        ldiq    v0, -1;                                         \
        RET;                                                    \
LLABEL(name,1):

#define __LEAF(p,n,e)                                           \
        LEAF(___CONCAT(p,n),e)
#define __END(p,n)                                              \
        END(___CONCAT(p,n));                                    \
        _HIDDEN_FALIAS(n,___CONCAT(p,n));                       \
        _END(_HIDDEN(n))

#define __SYSCALL(p,name)                                       \
__LEAF(p,name,0);                       /* XXX # of args? */    \
        CALLSYS_ERROR(name)

#define __SYSCALL_NOERROR(p,name)                               \
__LEAF(p,name,0);                       /* XXX # of args? */    \
        CALLSYS_NOERROR(name)


#define __RSYSCALL(p,name)                                      \
        __SYSCALL(p,name);                                      \
        RET;                                                    \
__END(p,name)

#define __RSYSCALL_NOERROR(p,name)                              \
        __SYSCALL_NOERROR(p,name);                              \
        RET;                                                    \
__END(p,name)


#define __PSEUDO(p,label,name)                                  \
__LEAF(p,label,0);                      /* XXX # of args? */    \
        CALLSYS_ERROR(name);                                    \
        RET;                                                    \
__END(p,label);

#define __PSEUDO_NOERROR(p,label,name)                          \
__LEAF(p,label,0);                      /* XXX # of args? */    \
        CALLSYS_NOERROR(name);                                  \
        RET;                                                    \
__END(p,label);

#define ALIAS(prefix,name) WEAK_ALIAS(name, ___CONCAT(prefix,name));

/*
 * For the thread_safe versions, we prepend _thread_sys_ to the function
 * name so that the 'C' wrapper can go around the real name.
 */
# define SYSCALL(x)             ALIAS(_thread_sys_,x) \
                                __SYSCALL(_thread_sys_,x)
# define SYSCALL_NOERROR(x)     ALIAS(_thread_sys_,x) \
                                __SYSCALL_NOERROR(_thread_sys_,x)
# define RSYSCALL(x)            ALIAS(_thread_sys_,x) \
                                __RSYSCALL(_thread_sys_,x); \
                                _END(x)
# define RSYSCALL_HIDDEN(x)     __RSYSCALL(_thread_sys_,x)
# define RSYSCALL_NOERROR(x)    ALIAS(_thread_sys_,x) \
                                __RSYSCALL_NOERROR(_thread_sys_,x); \
                                _END(x)
# define PSEUDO(x,y)            ALIAS(_thread_sys_,x) \
                                __PSEUDO(_thread_sys_,x,y); \
                                _END(x)
# define PSEUDO_NOERROR(x,y)    ALIAS(_thread_sys_,x) \
                                __PSEUDO_NOERROR(_thread_sys_,x,y); \
                                _END(x)
# define SYSLEAF_HIDDEN(x,e)    __LEAF(_thread_sys_,x,e)
# define SYSLEAF(x,e)           ALIAS(_thread_sys_,x) \
                                SYSLEAF_HIDDEN(x,e)
# define SYSCALL_END_HIDDEN(x)  __END(_thread_sys_,x)
# define SYSCALL_END(x)         SYSCALL_END_HIDDEN(x); \
                                _END(x)