xref: /illumos-gate/usr/src/lib/libc/i386/threads/machdep.c (revision 88f8b78a88cbdc6d8c1af5c3e54bc49d25095c98)
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, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2005 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_syscall(&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 	ulwp->ul_gs = LWPGS_SEL;
78 	ucp->uc_mcontext.gregs[GS] = (greg_t)ulwp->ul_gs;
79 
80 	/* top-of-stack must be rounded down to STACK_ALIGN */
81 	stack = (uint32_t *)(((uintptr_t)stk + stksize) & ~(STACK_ALIGN-1));
82 
83 	/* set up top stack frame */
84 	*--stack = 0;
85 	*--stack = 0;
86 	*--stack = (uint32_t)ulwp;
87 	*--stack = (uint32_t)_lwp_start;
88 
89 	/* fill in registers of interest */
90 	ucp->uc_flags |= UC_CPU;
91 	ucp->uc_mcontext.gregs[EIP] = (greg_t)func;
92 	ucp->uc_mcontext.gregs[UESP] = (greg_t)stack;
93 	ucp->uc_mcontext.gregs[EBP] = (greg_t)(stack+2);
94 
95 	return (0);
96 }
97 
98 /*
99  * Machine-dependent startup code for a newly-created thread.
100  */
101 void *
102 _thr_setup(ulwp_t *self)
103 {
104 	self->ul_ustack.ss_sp = (void *)(self->ul_stktop - self->ul_stksiz);
105 	self->ul_ustack.ss_size = self->ul_stksiz;
106 	self->ul_ustack.ss_flags = 0;
107 	(void) _private_setustack(&self->ul_ustack);
108 
109 	tls_setup();
110 
111 	/* signals have been deferred until now */
112 	sigon(self);
113 
114 	return (self->ul_startpc(self->ul_startarg));
115 }
116 
117 void
118 _fpinherit(ulwp_t *ulwp)
119 {
120 	ulwp->ul_fpuenv.ftag = 0xffffffff;
121 }
122 
123 void
124 getgregs(ulwp_t *ulwp, gregset_t rs)
125 {
126 	lwpstatus_t status;
127 
128 	if (getlwpstatus(ulwp->ul_lwpid, &status) == 0) {
129 		rs[EIP] = status.pr_reg[EIP];
130 		rs[EDI] = status.pr_reg[EDI];
131 		rs[ESI] = status.pr_reg[ESI];
132 		rs[EBP] = status.pr_reg[EBP];
133 		rs[EBX] = status.pr_reg[EBX];
134 		rs[UESP] = status.pr_reg[UESP];
135 	} else {
136 		rs[EIP] = 0;
137 		rs[EDI] = 0;
138 		rs[ESI] = 0;
139 		rs[EBP] = 0;
140 		rs[EBX] = 0;
141 		rs[UESP] = 0;
142 	}
143 }
144 
145 void
146 setgregs(ulwp_t *ulwp, gregset_t rs)
147 {
148 	lwpstatus_t status;
149 
150 	if (getlwpstatus(ulwp->ul_lwpid, &status) == 0) {
151 		status.pr_reg[EIP] = rs[EIP];
152 		status.pr_reg[EDI] = rs[EDI];
153 		status.pr_reg[ESI] = rs[ESI];
154 		status.pr_reg[EBP] = rs[EBP];
155 		status.pr_reg[EBX] = rs[EBX];
156 		status.pr_reg[UESP] = rs[UESP];
157 		(void) putlwpregs(ulwp->ul_lwpid, status.pr_reg);
158 	}
159 }
160 
161 int
162 __csigsetjmp(greg_t cs, greg_t ss, greg_t gs,
163 	greg_t fs, greg_t es, greg_t ds,
164 	greg_t edi, greg_t esi, greg_t ebp, greg_t esp,
165 	greg_t ebx, greg_t edx, greg_t ecx, greg_t eax, greg_t eip,
166 	sigjmp_buf env, int savemask)
167 {
168 	ucontext_t *ucp = (ucontext_t *)env;
169 	ulwp_t *self = curthread;
170 
171 	ucp->uc_link = self->ul_siglink;
172 	if (self->ul_ustack.ss_flags & SS_ONSTACK)
173 		ucp->uc_stack = self->ul_ustack;
174 	else {
175 		ucp->uc_stack.ss_sp =
176 			(void *)(self->ul_stktop - self->ul_stksiz);
177 		ucp->uc_stack.ss_size = self->ul_stksiz;
178 		ucp->uc_stack.ss_flags = 0;
179 	}
180 	ucp->uc_flags = UC_STACK | UC_CPU;
181 	if (savemask) {
182 		ucp->uc_flags |= UC_SIGMASK;
183 		enter_critical(self);
184 		ucp->uc_sigmask = self->ul_sigmask;
185 		exit_critical(self);
186 	}
187 	ucp->uc_mcontext.gregs[GS] = gs;
188 	ucp->uc_mcontext.gregs[FS] = fs;
189 	ucp->uc_mcontext.gregs[ES] = es;
190 	ucp->uc_mcontext.gregs[DS] = ds;
191 	ucp->uc_mcontext.gregs[EDI] = edi;
192 	ucp->uc_mcontext.gregs[ESI] = esi;
193 	ucp->uc_mcontext.gregs[EBP] = ebp;
194 	ucp->uc_mcontext.gregs[ESP] = esp + 4;
195 	ucp->uc_mcontext.gregs[EBX] = ebx;
196 	ucp->uc_mcontext.gregs[EDX] = edx;
197 	ucp->uc_mcontext.gregs[ECX] = ecx;
198 	ucp->uc_mcontext.gregs[EAX] = eax;
199 	ucp->uc_mcontext.gregs[TRAPNO] = 0;
200 	ucp->uc_mcontext.gregs[ERR] = 0;
201 	ucp->uc_mcontext.gregs[EIP] = eip;
202 	ucp->uc_mcontext.gregs[CS] = cs;
203 	ucp->uc_mcontext.gregs[EFL] = 0;
204 	ucp->uc_mcontext.gregs[UESP] = esp + 4;
205 	ucp->uc_mcontext.gregs[SS] = ss;
206 
207 	return (0);
208 }
209