1 /* SPDX-License-Identifier: LGPL-2.1 OR MIT */
2 /*
3 * Author: Paul Burton <paul.burton@mips.com>
4 * (C) Copyright 2018 MIPS Tech LLC
5 * (C) Copyright 2016-2022 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
6 */
7
8 /*
9 * RSEQ_SIG uses the break instruction. The instruction pattern is:
10 *
11 * On MIPS:
12 * 0350000d break 0x350
13 *
14 * On nanoMIPS:
15 * 00100350 break 0x350
16 *
17 * On microMIPS:
18 * 0000d407 break 0x350
19 *
20 * For nanoMIPS32 and microMIPS, the instruction stream is encoded as 16-bit
21 * halfwords, so the signature halfwords need to be swapped accordingly for
22 * little-endian.
23 */
24 #if defined(__nanomips__)
25 # ifdef __MIPSEL__
26 # define RSEQ_SIG 0x03500010
27 # else
28 # define RSEQ_SIG 0x00100350
29 # endif
30 #elif defined(__mips_micromips)
31 # ifdef __MIPSEL__
32 # define RSEQ_SIG 0xd4070000
33 # else
34 # define RSEQ_SIG 0x0000d407
35 # endif
36 #elif defined(__mips__)
37 # define RSEQ_SIG 0x0350000d
38 #else
39 /* Unknown MIPS architecture. */
40 #endif
41
42 #define rseq_smp_mb() __asm__ __volatile__ ("sync" ::: "memory")
43 #define rseq_smp_rmb() rseq_smp_mb()
44 #define rseq_smp_wmb() rseq_smp_mb()
45
46 #define rseq_smp_load_acquire(p) \
47 __extension__ ({ \
48 rseq_unqual_scalar_typeof(*(p)) ____p1 = RSEQ_READ_ONCE(*(p)); \
49 rseq_smp_mb(); \
50 ____p1; \
51 })
52
53 #define rseq_smp_acquire__after_ctrl_dep() rseq_smp_rmb()
54
55 #define rseq_smp_store_release(p, v) \
56 do { \
57 rseq_smp_mb(); \
58 RSEQ_WRITE_ONCE(*(p), v); \
59 } while (0)
60
61 #if _MIPS_SZLONG == 64
62 # define LONG ".dword"
63 # define LONG_LA "dla"
64 # define LONG_L "ld"
65 # define LONG_S "sd"
66 # define LONG_ADDI "daddiu"
67 # define U32_U64_PAD(x) x
68 #elif _MIPS_SZLONG == 32
69 # define LONG ".word"
70 # define LONG_LA "la"
71 # define LONG_L "lw"
72 # define LONG_S "sw"
73 # define LONG_ADDI "addiu"
74 # ifdef __BIG_ENDIAN
75 # define U32_U64_PAD(x) "0x0, " x
76 # else
77 # define U32_U64_PAD(x) x ", 0x0"
78 # endif
79 #else
80 # error unsupported _MIPS_SZLONG
81 #endif
82
83 #define __RSEQ_ASM_DEFINE_TABLE(label, version, flags, start_ip, \
84 post_commit_offset, abort_ip) \
85 ".pushsection __rseq_cs, \"aw\"\n\t" \
86 ".balign 32\n\t" \
87 __rseq_str(label) ":\n\t" \
88 ".word " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \
89 LONG " " U32_U64_PAD(__rseq_str(start_ip)) "\n\t" \
90 LONG " " U32_U64_PAD(__rseq_str(post_commit_offset)) "\n\t" \
91 LONG " " U32_U64_PAD(__rseq_str(abort_ip)) "\n\t" \
92 ".popsection\n\t" \
93 ".pushsection __rseq_cs_ptr_array, \"aw\"\n\t" \
94 LONG " " U32_U64_PAD(__rseq_str(label) "b") "\n\t" \
95 ".popsection\n\t"
96
97 #define RSEQ_ASM_DEFINE_TABLE(label, start_ip, post_commit_ip, abort_ip) \
98 __RSEQ_ASM_DEFINE_TABLE(label, 0x0, 0x0, start_ip, \
99 (post_commit_ip - start_ip), abort_ip)
100
101 /*
102 * Exit points of a rseq critical section consist of all instructions outside
103 * of the critical section where a critical section can either branch to or
104 * reach through the normal course of its execution. The abort IP and the
105 * post-commit IP are already part of the __rseq_cs section and should not be
106 * explicitly defined as additional exit points. Knowing all exit points is
107 * useful to assist debuggers stepping over the critical section.
108 */
109 #define RSEQ_ASM_DEFINE_EXIT_POINT(start_ip, exit_ip) \
110 ".pushsection __rseq_exit_point_array, \"aw\"\n\t" \
111 LONG " " U32_U64_PAD(__rseq_str(start_ip)) "\n\t" \
112 LONG " " U32_U64_PAD(__rseq_str(exit_ip)) "\n\t" \
113 ".popsection\n\t"
114
115 #define RSEQ_ASM_STORE_RSEQ_CS(label, cs_label, rseq_cs) \
116 RSEQ_INJECT_ASM(1) \
117 LONG_LA " $4, " __rseq_str(cs_label) "\n\t" \
118 LONG_S " $4, %[" __rseq_str(rseq_cs) "]\n\t" \
119 __rseq_str(label) ":\n\t"
120
121 #define RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, label) \
122 RSEQ_INJECT_ASM(2) \
123 "lw $4, %[" __rseq_str(current_cpu_id) "]\n\t" \
124 "bne $4, %[" __rseq_str(cpu_id) "], " __rseq_str(label) "\n\t"
125
126 #define __RSEQ_ASM_DEFINE_ABORT(table_label, label, teardown, \
127 abort_label, version, flags, \
128 start_ip, post_commit_offset, abort_ip) \
129 ".balign 32\n\t" \
130 __rseq_str(table_label) ":\n\t" \
131 ".word " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \
132 LONG " " U32_U64_PAD(__rseq_str(start_ip)) "\n\t" \
133 LONG " " U32_U64_PAD(__rseq_str(post_commit_offset)) "\n\t" \
134 LONG " " U32_U64_PAD(__rseq_str(abort_ip)) "\n\t" \
135 ".word " __rseq_str(RSEQ_SIG) "\n\t" \
136 __rseq_str(label) ":\n\t" \
137 teardown \
138 "b %l[" __rseq_str(abort_label) "]\n\t"
139
140 #define RSEQ_ASM_DEFINE_ABORT(table_label, label, teardown, abort_label, \
141 start_ip, post_commit_ip, abort_ip) \
142 __RSEQ_ASM_DEFINE_ABORT(table_label, label, teardown, \
143 abort_label, 0x0, 0x0, start_ip, \
144 (post_commit_ip - start_ip), abort_ip)
145
146 #define RSEQ_ASM_DEFINE_CMPFAIL(label, teardown, cmpfail_label) \
147 __rseq_str(label) ":\n\t" \
148 teardown \
149 "b %l[" __rseq_str(cmpfail_label) "]\n\t"
150
151 /* Per-cpu-id indexing. */
152
153 #define RSEQ_TEMPLATE_CPU_ID
154 #define RSEQ_TEMPLATE_MO_RELAXED
155 #include "rseq-mips-bits.h"
156 #undef RSEQ_TEMPLATE_MO_RELAXED
157
158 #define RSEQ_TEMPLATE_MO_RELEASE
159 #include "rseq-mips-bits.h"
160 #undef RSEQ_TEMPLATE_MO_RELEASE
161 #undef RSEQ_TEMPLATE_CPU_ID
162
163 /* Per-mm-cid indexing. */
164
165 #define RSEQ_TEMPLATE_MM_CID
166 #define RSEQ_TEMPLATE_MO_RELAXED
167 #include "rseq-mips-bits.h"
168 #undef RSEQ_TEMPLATE_MO_RELAXED
169
170 #define RSEQ_TEMPLATE_MO_RELEASE
171 #include "rseq-mips-bits.h"
172 #undef RSEQ_TEMPLATE_MO_RELEASE
173 #undef RSEQ_TEMPLATE_MM_CID
174
175 /* APIs which are not based on cpu ids. */
176
177 #define RSEQ_TEMPLATE_CPU_ID_NONE
178 #define RSEQ_TEMPLATE_MO_RELAXED
179 #include "rseq-mips-bits.h"
180 #undef RSEQ_TEMPLATE_MO_RELAXED
181 #undef RSEQ_TEMPLATE_CPU_ID_NONE
182
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