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linux-aarch64-ipa.c
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1 /* GNU/Linux/AArch64 specific low level interface, for the in-process
2 agent library for GDB.
3
4 Copyright (C) 2015-2018 Free Software Foundation, Inc.
5
6 This file is part of GDB.
7
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
12
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <http://www.gnu.org/licenses/>. */
20
21 #include "server.h"
22 #include <sys/mman.h>
23 #include "tracepoint.h"
24 #include <elf.h>
25 #ifdef HAVE_GETAUXVAL
26 #include <sys/auxv.h>
27 #endif
28 #include "linux-aarch64-tdesc.h"
29
30 /* Each register saved by the jump pad is in a 16 byte cell. */
31 #define FT_CR_SIZE 16
32
33 #define FT_CR_FPCR 0
34 #define FT_CR_FPSR 1
35 #define FT_CR_CPSR 2
36 #define FT_CR_PC 3
37 #define FT_CR_SP 4
38 #define FT_CR_X0 5
39 #define FT_CR_GPR(n) (FT_CR_X0 + (n))
40 #define FT_CR_FPR(n) (FT_CR_GPR (31) + (n))
41
42 /* Mapping between registers collected by the jump pad and GDB's register
43 array layout used by regcache.
44
45 See linux-aarch64-low.c (aarch64_install_fast_tracepoint_jump_pad) for
46 more details. */
47
48 static const int aarch64_ft_collect_regmap[] = {
49 FT_CR_GPR (0),
50 FT_CR_GPR (1),
51 FT_CR_GPR (2),
52 FT_CR_GPR (3),
53 FT_CR_GPR (4),
54 FT_CR_GPR (5),
55 FT_CR_GPR (6),
56 FT_CR_GPR (7),
57 FT_CR_GPR (8),
58 FT_CR_GPR (9),
59 FT_CR_GPR (10),
60 FT_CR_GPR (11),
61 FT_CR_GPR (12),
62 FT_CR_GPR (13),
63 FT_CR_GPR (14),
64 FT_CR_GPR (15),
65 FT_CR_GPR (16),
66 FT_CR_GPR (17),
67 FT_CR_GPR (18),
68 FT_CR_GPR (19),
69 FT_CR_GPR (20),
70 FT_CR_GPR (21),
71 FT_CR_GPR (22),
72 FT_CR_GPR (23),
73 FT_CR_GPR (24),
74 FT_CR_GPR (25),
75 FT_CR_GPR (26),
76 FT_CR_GPR (27),
77 FT_CR_GPR (28),
78 /* FP */
79 FT_CR_GPR (29),
80 /* LR */
81 FT_CR_GPR (30),
82 FT_CR_SP,
83 FT_CR_PC,
84 FT_CR_CPSR,
85 FT_CR_FPR (0),
86 FT_CR_FPR (1),
87 FT_CR_FPR (2),
88 FT_CR_FPR (3),
89 FT_CR_FPR (4),
90 FT_CR_FPR (5),
91 FT_CR_FPR (6),
92 FT_CR_FPR (7),
93 FT_CR_FPR (8),
94 FT_CR_FPR (9),
95 FT_CR_FPR (10),
96 FT_CR_FPR (11),
97 FT_CR_FPR (12),
98 FT_CR_FPR (13),
99 FT_CR_FPR (14),
100 FT_CR_FPR (15),
101 FT_CR_FPR (16),
102 FT_CR_FPR (17),
103 FT_CR_FPR (18),
104 FT_CR_FPR (19),
105 FT_CR_FPR (20),
106 FT_CR_FPR (21),
107 FT_CR_FPR (22),
108 FT_CR_FPR (23),
109 FT_CR_FPR (24),
110 FT_CR_FPR (25),
111 FT_CR_FPR (26),
112 FT_CR_FPR (27),
113 FT_CR_FPR (28),
114 FT_CR_FPR (29),
115 FT_CR_FPR (30),
116 FT_CR_FPR (31),
117 FT_CR_FPSR,
118 FT_CR_FPCR
119 };
120
121 #define AARCH64_NUM_FT_COLLECT_GREGS \
122 (sizeof (aarch64_ft_collect_regmap) / sizeof(aarch64_ft_collect_regmap[0]))
123
124 /* Fill in REGCACHE with registers saved by the jump pad in BUF. */
125
126 void
127 supply_fast_tracepoint_registers (struct regcache *regcache,
128 const unsigned char *buf)
129 {
130 int i;
131
132 for (i = 0; i < AARCH64_NUM_FT_COLLECT_GREGS; i++)
133 supply_register (regcache, i,
134 ((char *) buf)
135 + (aarch64_ft_collect_regmap[i] * FT_CR_SIZE));
136 }
137
138 ULONGEST
139 get_raw_reg (const unsigned char *raw_regs, int regnum)
140 {
141 if (regnum >= AARCH64_NUM_FT_COLLECT_GREGS)
142 return 0;
143
144 return *(ULONGEST *) (raw_regs
145 + aarch64_ft_collect_regmap[regnum] * FT_CR_SIZE);
146 }
147
148 /* Return target_desc to use for IPA, given the tdesc index passed by
149 gdbserver. Index is ignored, since we have only one tdesc
150 at the moment. */
151
152 const struct target_desc *
153 get_ipa_tdesc (int idx)
154 {
155 return aarch64_linux_read_description ();
156 }
157
158 /* Allocate buffer for the jump pads. The branch instruction has a reach
159 of +/- 128MiB, and the executable is loaded at 0x400000 (4MiB).
160 To maximize the area of executable that can use tracepoints, try
161 allocating at 0x400000 - size initially, decreasing until we hit
162 a free area. */
163
164 void *
165 alloc_jump_pad_buffer (size_t size)
166 {
167 uintptr_t addr;
168 uintptr_t exec_base = getauxval (AT_PHDR);
169 int pagesize;
170 void *res;
171
172 if (exec_base == 0)
173 exec_base = 0x400000;
174
175 pagesize = sysconf (_SC_PAGE_SIZE);
176 if (pagesize == -1)
177 perror_with_name ("sysconf");
178
179 addr = exec_base - size;
180
181 /* size should already be page-aligned, but this can't hurt. */
182 addr &= ~(pagesize - 1);
183
184 /* Search for a free area. If we hit 0, we're out of luck. */
185 for (; addr; addr -= pagesize)
186 {
187 /* No MAP_FIXED - we don't want to zap someone's mapping. */
188 res = mmap ((void *) addr, size,
189 PROT_READ | PROT_WRITE | PROT_EXEC,
190 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
191
192 /* If we got what we wanted, return. */
193 if ((uintptr_t) res == addr)
194 return res;
195
196 /* If we got a mapping, but at a wrong address, undo it. */
197 if (res != MAP_FAILED)
198 munmap (res, size);
199 }
200
201 return NULL;
202 }
203
204 void
205 initialize_low_tracepoint (void)
206 {
207 aarch64_linux_read_description ();
208 }
FT_CR_FPCR
#define FT_CR_FPCR
Definition: linux-aarch64-ipa.c:33
AARCH64_NUM_FT_COLLECT_GREGS
#define AARCH64_NUM_FT_COLLECT_GREGS
Definition: linux-aarch64-ipa.c:121
FT_CR_CPSR
#define FT_CR_CPSR
Definition: linux-aarch64-ipa.c:35
regnum
regnum
Definition: linux-xtensa-low.c:34
regcache
Definition: regcache.h:31
FT_CR_FPSR
#define FT_CR_FPSR
Definition: linux-aarch64-ipa.c:34
FT_CR_PC
#define FT_CR_PC
Definition: linux-aarch64-ipa.c:36
FT_CR_SP
#define FT_CR_SP
Definition: linux-aarch64-ipa.c:37
FT_CR_GPR
#define FT_CR_GPR(n)
Definition: linux-aarch64-ipa.c:39
FT_CR_SIZE
#define FT_CR_SIZE
Definition: linux-aarch64-ipa.c:31
alloc_jump_pad_buffer
void * alloc_jump_pad_buffer(size_t size)
Definition: linux-aarch64-ipa.c:165
tracepoint.h
server.h
get_raw_reg
ULONGEST get_raw_reg(const unsigned char *raw_regs, int regnum)
Definition: linux-aarch64-ipa.c:139
aarch64_linux_read_description
const target_desc * aarch64_linux_read_description()
Definition: linux-aarch64-tdesc.c:28
FT_CR_FPR
#define FT_CR_FPR(n)
Definition: linux-aarch64-ipa.c:40
initialize_low_tracepoint
void initialize_low_tracepoint(void)
Definition: linux-aarch64-ipa.c:205
target_desc
Definition: tdesc.h:33
perror_with_name
void perror_with_name(const char *string)
Definition: utils.c:57
ULONGEST
unsigned long long ULONGEST
Definition: common-types.h:53
aarch64_ft_collect_regmap
static const int aarch64_ft_collect_regmap[]
Definition: linux-aarch64-ipa.c:48
supply_register
void supply_register(struct regcache *regcache, int n, const void *buf)
Definition: regcache.c:318
get_ipa_tdesc
const struct target_desc * get_ipa_tdesc(int idx)
Definition: linux-aarch64-ipa.c:153
linux-aarch64-tdesc.h
supply_fast_tracepoint_registers
void supply_fast_tracepoint_registers(struct regcache *regcache, const unsigned char *buf)
Definition: linux-aarch64-ipa.c:127