Print this page
15254 %ymm registers not restored after signal handler
15367 x86 getfpregs() summons corrupting %xmm ghosts
15333 want x86 /proc xregs support (libc_db, libproc, mdb, etc.)
15336 want libc functions for extended ucontext_t
15334 want ps_lwphandle-specific reg routines
15328 FPU_CW_INIT mistreats reserved bit
15335 i86pc fpu_subr.c isn't really platform-specific
15332 setcontext(2) isn't actually noreturn
15331 need <sys/stdalign.h>
Change-Id: I7060aa86042dfb989f77fc3323c065ea2eafa9ad
Conflicts:
usr/src/uts/common/fs/proc/prcontrol.c
usr/src/uts/intel/os/archdep.c
usr/src/uts/intel/sys/ucontext.h
usr/src/uts/intel/syscall/getcontext.c
| Split |
Close |
| Expand all |
| Collapse all |
--- old/usr/src/lib/libc/i386/gen/makectxt.c
+++ new/usr/src/lib/libc/i386/gen/makectxt.c
1 1 /*
2 2 * CDDL HEADER START
3 3 *
4 4 * The contents of this file are subject to the terms of the
5 5 * Common Development and Distribution License (the "License").
6 6 * You may not use this file except in compliance with the License.
7 7 *
8 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 9 * or http://www.opensolaris.org/os/licensing.
10 10 * See the License for the specific language governing permissions
11 11 * and limitations under the License.
12 12 *
13 13 * When distributing Covered Code, include this CDDL HEADER in each
14 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 15 * If applicable, add the following below this CDDL HEADER, with the
16 16 * fields enclosed by brackets "[]" replaced with your own identifying
17 17 * information: Portions Copyright [yyyy] [name of copyright owner]
|
↓ open down ↓ |
17 lines elided |
↑ open up ↑ |
18 18 *
19 19 * CDDL HEADER END
20 20 */
21 21
22 22 /*
23 23 * Copyright 2008 Sun Microsystems, Inc. All rights reserved.
24 24 * Use is subject to license terms.
25 25 */
26 26
27 27 /* Copyright (c) 1988 AT&T */
28 -/* All Rights Reserved */
28 +/* All Rights Reserved */
29 29
30 +/*
31 + * Copyright 2023 Oxide Computer Company
32 + */
33 +
30 34 #pragma weak _makecontext = makecontext
31 35
32 36 #include "lint.h"
33 37 #include <stdarg.h>
34 38 #include <ucontext.h>
35 39 #include <sys/stack.h>
40 +#include <sys/auxv.h>
41 +#include <errno.h>
42 +#include "libc.h"
36 43
37 44 /*
38 45 * The ucontext_t that the user passes in must have been primed with a
39 46 * call to getcontext(2), have the uc_stack member set to reflect the
40 47 * stack which this context will use, and have the uc_link member set
41 48 * to the context which should be resumed when this context returns.
42 49 * When makecontext() returns, the ucontext_t will be set to run the
43 50 * given function with the given parameters on the stack specified by
44 51 * uc_stack, and which will return to the ucontext_t specified by uc_link.
45 52 */
46 53
47 54 /*
48 55 * The original i386 ABI said that the stack pointer need be only 4-byte
49 56 * aligned before a function call (STACK_ALIGN == 4). The ABI supplement
50 57 * version 1.0 changed the required alignment to 16-byte for the benefit of
51 58 * floating point code compiled using sse2. The compiler assumes this
52 59 * alignment and maintains it for calls it generates. If the stack is
53 60 * initially properly aligned, it will continue to be so aligned. If it is
54 61 * not initially so aligned, it will never become so aligned.
55 62 *
56 63 * One slightly confusing detail to keep in mind is that the 16-byte
57 64 * alignment (%esp & 0xf == 0) is true just *before* the call instruction.
58 65 * The call instruction will then push a return value, decrementing %esp by
59 66 * 4. Therefore, if one dumps %esp at the at the very first instruction in
60 67 * a function, it will end with a 0xc. The compiler expects this and
61 68 * compensates for it properly.
62 69 *
63 70 * Note: If you change this value, you need to change it in the following
64 71 * files as well:
65 72 *
66 73 * - lib/libc/i386/threads/machdep.c
67 74 * - lib/crt/i386/crti.s
68 75 * - lib/crt/i386/crt1.s
69 76 */
70 77 #undef STACK_ALIGN
71 78 #define STACK_ALIGN 16
72 79
73 80 static void resumecontext(void);
74 81
75 82 void
76 83 makecontext(ucontext_t *ucp, void (*func)(), int argc, ...)
77 84 {
78 85 long *sp;
79 86 long *tsp;
80 87 va_list ap;
81 88 size_t size;
82 89
83 90 ucp->uc_mcontext.gregs[EIP] = (greg_t)func;
84 91
85 92 size = sizeof (long) * (argc + 1);
86 93
87 94 tsp = (long *)(((uintptr_t)ucp->uc_stack.ss_sp +
88 95 ucp->uc_stack.ss_size - size) & ~(STACK_ALIGN - 1));
89 96
90 97 /*
91 98 * Since we're emulating the call instruction, we must push the
92 99 * return address (which involves adjusting the stack pointer to
93 100 * have the proper 4-byte bias).
94 101 */
95 102 sp = tsp - 1;
96 103
97 104 *sp = (long)resumecontext; /* return address */
98 105
99 106 ucp->uc_mcontext.gregs[UESP] = (greg_t)sp;
100 107
101 108 /*
102 109 * "push" all the arguments
103 110 */
104 111 va_start(ap, argc);
105 112 while (argc-- > 0)
106 113 *tsp++ = va_arg(ap, long);
107 114 va_end(ap);
|
↓ open down ↓ |
62 lines elided |
↑ open up ↑ |
108 115 }
109 116
110 117
111 118 static void
112 119 resumecontext(void)
113 120 {
114 121 ucontext_t uc;
115 122
116 123 (void) getcontext(&uc);
117 124 (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);
118 184 }
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX