11.11Sriastrad/*	$NetBSD: _lwp.c,v 1.11 2025/04/25 01:18:24 riastradh Exp $	*/
21.2Sthorpej
31.2Sthorpej/*
41.2Sthorpej * Copyright (c) 2001 The NetBSD Foundation, Inc.
51.2Sthorpej * All rights reserved.
61.2Sthorpej *
71.2Sthorpej * This code is derived from software contributed to The NetBSD Foundation
81.2Sthorpej * by Wayne Knowles
91.2Sthorpej *
101.2Sthorpej * Redistribution and use in source and binary forms, with or without
111.2Sthorpej * modification, are permitted provided that the following conditions
121.2Sthorpej * are met:
131.2Sthorpej * 1. Redistributions of source code must retain the above copyright
141.2Sthorpej *    notice, this list of conditions and the following disclaimer.
151.2Sthorpej * 2. Redistributions in binary form must reproduce the above copyright
161.2Sthorpej *    notice, this list of conditions and the following disclaimer in the
171.2Sthorpej *    documentation and/or other materials provided with the distribution.
181.2Sthorpej *
191.2Sthorpej * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
201.2Sthorpej * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
211.2Sthorpej * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
221.2Sthorpej * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
231.2Sthorpej * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
241.2Sthorpej * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
251.2Sthorpej * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
261.2Sthorpej * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
271.2Sthorpej * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
281.2Sthorpej * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
291.2Sthorpej * POSSIBILITY OF SUCH DAMAGE.
301.2Sthorpej */
311.2Sthorpej
321.4Slukem#include <sys/cdefs.h>
331.4Slukem#if defined(LIBC_SCCS) && !defined(lint)
341.11Sriastrad__RCSID("$NetBSD: _lwp.c,v 1.11 2025/04/25 01:18:24 riastradh Exp $");
351.4Slukem#endif /* LIBC_SCCS and not lint */
361.4Slukem
371.3Skleink#include "namespace.h"
381.10Sriastrad
391.11Sriastrad#include <sys/param.h>
401.2Sthorpej#include <sys/types.h>
411.10Sriastrad
421.2Sthorpej#include <lwp.h>
431.2Sthorpej#include <stdlib.h>
441.10Sriastrad#include <ucontext.h>
451.2Sthorpej
461.9Schristos#include <machine/lwp_private.h>
471.9Schristos
481.8Smatt#if defined(__mips_o32) || defined(__mips_o64)
491.8Smatt#define CALLFRAME_SIZ	(6 * sizeof(void *))
501.8Smatt#else
511.8Smatt#define CALLFRAME_SIZ	(4 * sizeof(uint64_t))
521.8Smatt#endif
531.2Sthorpej
541.7Smattvoid
551.7Smatt_lwp_makecontext(ucontext_t *u, void (*start)(void *),
561.7Smatt	void *arg, void *tcb, caddr_t stack_base, size_t stack_size)
571.2Sthorpej{
581.2Sthorpej	caddr_t sp;
591.2Sthorpej	__greg_t *gr;
601.2Sthorpej
611.2Sthorpej	getcontext(u);
621.2Sthorpej	gr = u->uc_mcontext.__gregs;
631.2Sthorpej	u->uc_link = NULL;
641.2Sthorpej
651.2Sthorpej	u->uc_stack.ss_sp = stack_base;
661.2Sthorpej	u->uc_stack.ss_size = stack_size;
671.2Sthorpej	sp = stack_base + stack_size - CALLFRAME_SIZ;
681.2Sthorpej
691.7Smatt	gr[_REG_EPC] = (uintptr_t) start;
701.7Smatt	gr[_REG_T9] = (uintptr_t) start; /* required for .abicalls */
711.7Smatt	gr[_REG_RA] = (uintptr_t) _lwp_exit;
721.7Smatt	gr[_REG_A0] = (uintptr_t) arg;
731.11Sriastrad	gr[_REG_SP] = (uintptr_t) sp & ~STACK_ALIGNBYTES;
741.7Smatt	u->uc_mcontext._mc_tlsbase =
751.7Smatt	    (uintptr_t)tcb + TLS_TP_OFFSET + sizeof(struct tls_tcb);
761.6Sjoerg	u->uc_flags |= _UC_TLSBASE;
771.2Sthorpej}
78