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 /* Copyright (c) 1988 AT&T */
28 /* All Rights Reserved */
29
30 #pragma weak _makecontext = makecontext
31
32 #include "lint.h"
33 #include <stdarg.h>
34 #include <ucontext.h>
35 #include <sys/stack.h>
36
37 /*
38 * The ucontext_t that the user passes in must have been primed with a
39 * call to getcontext(2), have the uc_stack member set to reflect the
40 * stack which this context will use, and have the uc_link member set
41 * to the context which should be resumed when this context returns.
42 * When makecontext() returns, the ucontext_t will be set to run the
43 * given function with the given parameters on the stack specified by
44 * uc_stack, and which will return to the ucontext_t specified by uc_link.
45 */
46
47 /*
48 * The original i386 ABI said that the stack pointer need be only 4-byte
49 * aligned before a function call (STACK_ALIGN == 4). The ABI supplement
50 * version 1.0 changed the required alignment to 16-byte for the benefit of
51 * floating point code compiled using sse2. The compiler assumes this
52 * alignment and maintains it for calls it generates. If the stack is
53 * initially properly aligned, it will continue to be so aligned. If it is
54 * not initially so aligned, it will never become so aligned.
55 *
98
99 ucp->uc_mcontext.gregs[UESP] = (greg_t)sp;
100
101 /*
102 * "push" all the arguments
103 */
104 va_start(ap, argc);
105 while (argc-- > 0)
106 *tsp++ = va_arg(ap, long);
107 va_end(ap);
108 }
109
110
111 static void
112 resumecontext(void)
113 {
114 ucontext_t uc;
115
116 (void) getcontext(&uc);
117 (void) setcontext(uc.uc_link);
118 }
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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 /* Copyright (c) 1988 AT&T */
28 /* All Rights Reserved */
29
30 /*
31 * Copyright 2023 Oxide Computer Company
32 */
33
34 #pragma weak _makecontext = makecontext
35
36 #include "lint.h"
37 #include <stdarg.h>
38 #include <ucontext.h>
39 #include <sys/stack.h>
40 #include <sys/auxv.h>
41 #include <errno.h>
42 #include "libc.h"
43
44 /*
45 * The ucontext_t that the user passes in must have been primed with a
46 * call to getcontext(2), have the uc_stack member set to reflect the
47 * stack which this context will use, and have the uc_link member set
48 * to the context which should be resumed when this context returns.
49 * When makecontext() returns, the ucontext_t will be set to run the
50 * given function with the given parameters on the stack specified by
51 * uc_stack, and which will return to the ucontext_t specified by uc_link.
52 */
53
54 /*
55 * The original i386 ABI said that the stack pointer need be only 4-byte
56 * aligned before a function call (STACK_ALIGN == 4). The ABI supplement
57 * version 1.0 changed the required alignment to 16-byte for the benefit of
58 * floating point code compiled using sse2. The compiler assumes this
59 * alignment and maintains it for calls it generates. If the stack is
60 * initially properly aligned, it will continue to be so aligned. If it is
61 * not initially so aligned, it will never become so aligned.
62 *
105
106 ucp->uc_mcontext.gregs[UESP] = (greg_t)sp;
107
108 /*
109 * "push" all the arguments
110 */
111 va_start(ap, argc);
112 while (argc-- > 0)
113 *tsp++ = va_arg(ap, long);
114 va_end(ap);
115 }
116
117
118 static void
119 resumecontext(void)
120 {
121 ucontext_t uc;
122
123 (void) getcontext(&uc);
124 (void) setcontext(uc.uc_link);
125 }
126
127 /*
128 * This is the ISA-specific allocation logic for allocating and setting up an
129 * extended ucontext_t. In particular, right now we need to allocate and add
130 * space for the UC_XSAVE member if we have the appropriate hardware support.
131 * The i386 / amd64 versions could be consolidated in a single x86 impl, but we
132 * don't have that right now.
133 */
134 ucontext_t *
135 ucontext_alloc(uint32_t flags)
136 {
137 boolean_t do_xsave = B_FALSE;
138 size_t to_alloc = sizeof (ucontext_t);
139 ucontext_t *ucp;
140
141 if (flags != 0) {
142 errno = EINVAL;
143 return (NULL);
144 }
145
146 /*
147 * This value isn't really 100% accurate. The xsave size is basically
148 * the worst case that we can have. The XMM / xsave structures aren't
149 * included in here, but are going to be enough to cover this. We can
150 * probably try to do a little better and should consider asking the
151 * kernel for something more accurate. In particular, the problem with
152 * tis is that it doesn't account for the right size of future-looking
153 * dynamic things, but then again neither does rtld. We'll deal with
154 * this when we have support for the xfd MSR and actually use it. For
155 * more information see uts/intel/os/fpu.c's big theory statement.
156 */
157 switch (___getauxval(AT_SUN_FPTYPE)) {
158 case AT_386_FPINFO_XSAVE:
159 case AT_386_FPINFO_XSAVE_AMD:
160 do_xsave = B_TRUE;
161 to_alloc += ___getauxval(AT_SUN_FPSIZE);
162 break;
163 default:
164 break;
165 }
166
167 ucp = calloc(1, to_alloc);
168 if (ucp == NULL) {
169 return (NULL);
170 }
171
172 if (do_xsave) {
173 uintptr_t addr = (uintptr_t)ucp;
174 ucp->uc_xsave = addr + sizeof (ucontext_t);
175 }
176
177 return (ucp);
178 }
179
180 void
181 ucontext_free(ucontext_t *ucp)
182 {
183 free(ucp);
184 }
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