xref: /titanic_50/usr/src/lib/libc/i386/threads/machdep.c (revision c7158ae983f5a04c4a998f468ecefba6d23ba721)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 #include "thr_uberdata.h"
30 #include <procfs.h>
31 #include <ucontext.h>
32 #include <setjmp.h>
33 
34 extern int getlwpstatus(thread_t, lwpstatus_t *);
35 extern int putlwpregs(thread_t, prgregset_t);
36 
37 int
38 setup_context(ucontext_t *ucp, void *(*func)(ulwp_t *),
39 	ulwp_t *ulwp, caddr_t stk, size_t stksize)
40 {
41 	static int initialized;
42 	static greg_t fs, es, ds, cs, ss;
43 
44 	uint32_t *stack;
45 
46 	if (!initialized) {
47 		ucontext_t uc;
48 
49 		/* do this once to load the segment registers */
50 		uc.uc_flags = UC_CPU;
51 		(void) __getcontext(&uc);
52 		fs = uc.uc_mcontext.gregs[FS];
53 		es = uc.uc_mcontext.gregs[ES];
54 		ds = uc.uc_mcontext.gregs[DS];
55 		cs = uc.uc_mcontext.gregs[CS];
56 		ss = uc.uc_mcontext.gregs[SS];
57 		initialized = 1;
58 	}
59 	/* clear the context and set the segment registers */
60 	(void) memset(ucp, 0, sizeof (*ucp));
61 	ucp->uc_mcontext.gregs[FS] = fs;
62 	ucp->uc_mcontext.gregs[ES] = es;
63 	ucp->uc_mcontext.gregs[DS] = ds;
64 	ucp->uc_mcontext.gregs[CS] = cs;
65 	ucp->uc_mcontext.gregs[SS] = ss;
66 
67 	/*
68 	 * Yuck.
69 	 * Use unused kernel pointer field in ucontext
70 	 * to pass down self pointer and set %gs selector
71 	 * value so __lwp_create() can setup %gs atomically.
72 	 * Without this we would need to block all signals
73 	 * and directly call __lwp_setprivate() in _thr_setup
74 	 * on the other side of __lwp_create().
75 	 */
76 	ucp->uc_mcontext.gregs[ESP] = (greg_t)ulwp;
77 	ucp->uc_mcontext.gregs[GS] = (greg_t)LWPGS_SEL;
78 
79 	/* top-of-stack must be rounded down to STACK_ALIGN */
80 	stack = (uint32_t *)(((uintptr_t)stk + stksize) & ~(STACK_ALIGN-1));
81 
82 	/* set up top stack frame */
83 	*--stack = 0;
84 	*--stack = 0;
85 	*--stack = (uint32_t)ulwp;
86 	*--stack = (uint32_t)_lwp_start;
87 
88 	/* fill in registers of interest */
89 	ucp->uc_flags |= UC_CPU;
90 	ucp->uc_mcontext.gregs[EIP] = (greg_t)func;
91 	ucp->uc_mcontext.gregs[UESP] = (greg_t)stack;
92 	ucp->uc_mcontext.gregs[EBP] = (greg_t)(stack+2);
93 
94 	return (0);
95 }
96 
97 /*
98  * Machine-dependent startup code for a newly-created thread.
99  */
100 void *
101 _thr_setup(ulwp_t *self)
102 {
103 	self->ul_ustack.ss_sp = (void *)(self->ul_stktop - self->ul_stksiz);
104 	self->ul_ustack.ss_size = self->ul_stksiz;
105 	self->ul_ustack.ss_flags = 0;
106 	(void) setustack(&self->ul_ustack);
107 
108 	update_sched(self);
109 	tls_setup();
110 
111 	/* signals have been deferred until now */
112 	sigon(self);
113 
114 	if (self->ul_cancel_pending == 2 && !self->ul_cancel_disabled)
115 		return (NULL);	/* cancelled by pthread_create() */
116 	return (self->ul_startpc(self->ul_startarg));
117 }
118 
119 void
120 _fpinherit(ulwp_t *ulwp)
121 {
122 	ulwp->ul_fpuenv.ftag = 0xffffffff;
123 }
124 
125 void
126 getgregs(ulwp_t *ulwp, gregset_t rs)
127 {
128 	lwpstatus_t status;
129 
130 	if (getlwpstatus(ulwp->ul_lwpid, &status) == 0) {
131 		rs[EIP] = status.pr_reg[EIP];
132 		rs[EDI] = status.pr_reg[EDI];
133 		rs[ESI] = status.pr_reg[ESI];
134 		rs[EBP] = status.pr_reg[EBP];
135 		rs[EBX] = status.pr_reg[EBX];
136 		rs[UESP] = status.pr_reg[UESP];
137 	} else {
138 		rs[EIP] = 0;
139 		rs[EDI] = 0;
140 		rs[ESI] = 0;
141 		rs[EBP] = 0;
142 		rs[EBX] = 0;
143 		rs[UESP] = 0;
144 	}
145 }
146 
147 void
148 setgregs(ulwp_t *ulwp, gregset_t rs)
149 {
150 	lwpstatus_t status;
151 
152 	if (getlwpstatus(ulwp->ul_lwpid, &status) == 0) {
153 		status.pr_reg[EIP] = rs[EIP];
154 		status.pr_reg[EDI] = rs[EDI];
155 		status.pr_reg[ESI] = rs[ESI];
156 		status.pr_reg[EBP] = rs[EBP];
157 		status.pr_reg[EBX] = rs[EBX];
158 		status.pr_reg[UESP] = rs[UESP];
159 		(void) putlwpregs(ulwp->ul_lwpid, status.pr_reg);
160 	}
161 }
162 
163 int
164 __csigsetjmp(greg_t cs, greg_t ss, greg_t gs,
165 	greg_t fs, greg_t es, greg_t ds,
166 	greg_t edi, greg_t esi, greg_t ebp, greg_t esp,
167 	greg_t ebx, greg_t edx, greg_t ecx, greg_t eax, greg_t eip,
168 	sigjmp_buf env, int savemask)
169 {
170 	ucontext_t *ucp = (ucontext_t *)env;
171 	ulwp_t *self = curthread;
172 
173 	ucp->uc_link = self->ul_siglink;
174 	if (self->ul_ustack.ss_flags & SS_ONSTACK)
175 		ucp->uc_stack = self->ul_ustack;
176 	else {
177 		ucp->uc_stack.ss_sp =
178 		    (void *)(self->ul_stktop - self->ul_stksiz);
179 		ucp->uc_stack.ss_size = self->ul_stksiz;
180 		ucp->uc_stack.ss_flags = 0;
181 	}
182 	ucp->uc_flags = UC_STACK | UC_CPU;
183 	if (savemask) {
184 		ucp->uc_flags |= UC_SIGMASK;
185 		enter_critical(self);
186 		ucp->uc_sigmask = self->ul_sigmask;
187 		exit_critical(self);
188 	}
189 	ucp->uc_mcontext.gregs[GS] = gs;
190 	ucp->uc_mcontext.gregs[FS] = fs;
191 	ucp->uc_mcontext.gregs[ES] = es;
192 	ucp->uc_mcontext.gregs[DS] = ds;
193 	ucp->uc_mcontext.gregs[EDI] = edi;
194 	ucp->uc_mcontext.gregs[ESI] = esi;
195 	ucp->uc_mcontext.gregs[EBP] = ebp;
196 	ucp->uc_mcontext.gregs[ESP] = esp + 4;
197 	ucp->uc_mcontext.gregs[EBX] = ebx;
198 	ucp->uc_mcontext.gregs[EDX] = edx;
199 	ucp->uc_mcontext.gregs[ECX] = ecx;
200 	ucp->uc_mcontext.gregs[EAX] = eax;
201 	ucp->uc_mcontext.gregs[TRAPNO] = 0;
202 	ucp->uc_mcontext.gregs[ERR] = 0;
203 	ucp->uc_mcontext.gregs[EIP] = eip;
204 	ucp->uc_mcontext.gregs[CS] = cs;
205 	ucp->uc_mcontext.gregs[EFL] = 0;
206 	ucp->uc_mcontext.gregs[UESP] = esp + 4;
207 	ucp->uc_mcontext.gregs[SS] = ss;
208 
209 	return (0);
210 }
211