1/* libunwind - a platform-independent unwind library
2   Copyright (C) 2008 Google, Inc
3	Contributed by Paul Pluzhnikov <ppluzhnikov@google.com>
4   Copyright (C) 2010 Konstantin Belousov <kib@freebsd.org>
5
6This file is part of libunwind.
7
8Permission is hereby granted, free of charge, to any person obtaining
9a copy of this software and associated documentation files (the
10"Software"), to deal in the Software without restriction, including
11without limitation the rights to use, copy, modify, merge, publish,
12distribute, sublicense, and/or sell copies of the Software, and to
13permit persons to whom the Software is furnished to do so, subject to
14the following conditions:
15
16The above copyright notice and this permission notice shall be
17included in all copies or substantial portions of the Software.
18
19THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
20EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
21MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
22NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
23LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
24OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
25WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
26
27#include "ucontext_i.h"
28
29/*  int _Ux86_64_getcontext (ucontext_t *ucp)
30
31  Saves the machine context in UCP necessary for libunwind.
32  Unlike the libc implementation, we don't save the signal mask
33  and hence avoid the cost of a system call per unwind.
34
35*/
36
37	.global _Ux86_64_getcontext
38	.type _Ux86_64_getcontext, @function
39_Ux86_64_getcontext:
40	.cfi_startproc
41
42	/* Callee saved: RBX, RBP, R12-R15  */
43	movq %r12, UC_MCONTEXT_GREGS_R12(%rdi)
44	movq %r13, UC_MCONTEXT_GREGS_R13(%rdi)
45	movq %r14, UC_MCONTEXT_GREGS_R14(%rdi)
46	movq %r15, UC_MCONTEXT_GREGS_R15(%rdi)
47	movq %rbp, UC_MCONTEXT_GREGS_RBP(%rdi)
48	movq %rbx, UC_MCONTEXT_GREGS_RBX(%rdi)
49
50	/* Save argument registers (not strictly needed, but setcontext
51	   restores them, so don't restore garbage).  */
52	movq %r8,  UC_MCONTEXT_GREGS_R8(%rdi)
53	movq %r9,  UC_MCONTEXT_GREGS_R9(%rdi)
54	movq %rdi, UC_MCONTEXT_GREGS_RDI(%rdi)
55	movq %rsi, UC_MCONTEXT_GREGS_RSI(%rdi)
56	movq %rdx, UC_MCONTEXT_GREGS_RDX(%rdi)
57	movq %rax, UC_MCONTEXT_GREGS_RAX(%rdi)
58	movq %rcx, UC_MCONTEXT_GREGS_RCX(%rdi)
59
60#if defined __linux__
61	/* Save fp state (not needed, except for setcontext not
62	   restoring garbage).  */
63	leaq UC_MCONTEXT_FPREGS_MEM(%rdi),%r8
64	movq %r8, UC_MCONTEXT_FPREGS_PTR(%rdi)
65	fnstenv (%r8)
66	stmxcsr FPREGS_OFFSET_MXCSR(%r8)
67#elif defined __FreeBSD__
68	fxsave UC_MCONTEXT_FPSTATE(%rdi)
69	movq $UC_MCONTEXT_FPOWNED_FPU,UC_MCONTEXT_OWNEDFP(%rdi)
70	movq $UC_MCONTEXT_FPFMT_XMM,UC_MCONTEXT_FPFORMAT(%rdi)
71	/* Save rflags and segment registers, so that sigreturn(2)
72	does not complain. */
73	pushfq
74	.cfi_adjust_cfa_offset 8
75	popq UC_MCONTEXT_RFLAGS(%rdi)
76	.cfi_adjust_cfa_offset -8
77	movl $0, UC_MCONTEXT_FLAGS(%rdi)
78	movw %cs, UC_MCONTEXT_CS(%rdi)
79	movw %ss, UC_MCONTEXT_SS(%rdi)
80#if 0
81	/* Setting the flags to 0 above disables restore of segment
82	   registers from the context */
83	movw %ds, UC_MCONTEXT_DS(%rdi)
84	movw %es, UC_MCONTEXT_ES(%rdi)
85	movw %fs, UC_MCONTEXT_FS(%rdi)
86	movw %gs, UC_MCONTEXT_GS(%rdi)
87#endif
88	movq $UC_MCONTEXT_MC_LEN_VAL, UC_MCONTEXT_MC_LEN(%rdi)
89#else
90#error Port me
91#endif
92
93	leaq 8(%rsp), %rax /* exclude this call.  */
94	movq %rax, UC_MCONTEXT_GREGS_RSP(%rdi)
95
96	movq 0(%rsp), %rax
97	movq %rax, UC_MCONTEXT_GREGS_RIP(%rdi)
98
99	xorq	%rax, %rax
100	retq
101	.cfi_endproc
102	.size _Ux86_64_getcontext, . - _Ux86_64_getcontext
103
104/*  int _Ux86_64_getcontext_trace (ucontext_t *ucp)
105
106  Saves limited machine context in UCP necessary for libunwind.
107  Unlike _Ux86_64_getcontext, saves only the parts needed for
108  fast trace. If fast trace fails, caller will have to get the
109  full context.
110*/
111
112	.global _Ux86_64_getcontext_trace
113	.hidden _Ux86_64_getcontext_trace
114	.type _Ux86_64_getcontext_trace, @function
115_Ux86_64_getcontext_trace:
116	.cfi_startproc
117
118	/* Save only RBP, RBX, RSP, RIP - exclude this call. */
119	movq %rbp, UC_MCONTEXT_GREGS_RBP(%rdi)
120	movq %rbx, UC_MCONTEXT_GREGS_RBX(%rdi)
121
122	leaq 8(%rsp), %rax
123	movq %rax, UC_MCONTEXT_GREGS_RSP(%rdi)
124
125	movq 0(%rsp), %rax
126	movq %rax, UC_MCONTEXT_GREGS_RIP(%rdi)
127
128	xorq	%rax, %rax
129	retq
130	.cfi_endproc
131	.size _Ux86_64_getcontext_trace, . - _Ux86_64_getcontext_trace
132
133      /* We do not need executable stack.  */
134      .section        .note.GNU-stack,"",@progbits
135