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a1217d97 | 1 | /* Target-dependent code for GNU/Linux on Nios II. |
61baf725 | 2 | Copyright (C) 2012-2017 Free Software Foundation, Inc. |
a1217d97 SL |
3 | Contributed by Mentor Graphics, Inc. |
4 | ||
5 | This file is part of GDB. | |
6 | ||
7 | This program is free software; you can redistribute it and/or modify | |
8 | it under the terms of the GNU General Public License as published by | |
9 | the Free Software Foundation; either version 3 of the License, or | |
10 | (at your option) any later version. | |
11 | ||
12 | This program is distributed in the hope that it will be useful, | |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
18 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ | |
19 | ||
20 | #include "defs.h" | |
21 | #include "frame.h" | |
a1217d97 SL |
22 | #include "osabi.h" |
23 | #include "solib-svr4.h" | |
24 | #include "trad-frame.h" | |
25 | #include "tramp-frame.h" | |
26 | #include "symtab.h" | |
27 | #include "regset.h" | |
28 | #include "regcache.h" | |
29 | #include "linux-tdep.h" | |
30 | #include "glibc-tdep.h" | |
31 | #include "nios2-tdep.h" | |
32 | ||
33 | #include "features/nios2-linux.c" | |
34 | ||
35 | /* Core file and register set support. */ | |
36 | ||
37 | /* Map from the normal register enumeration order to the order that | |
38 | registers appear in core files, which corresponds to the order | |
39 | of the register slots in the kernel's struct pt_regs. */ | |
40 | ||
41 | static const int reg_offsets[NIOS2_NUM_REGS] = | |
42 | { | |
43 | -1, 8, 9, 10, 11, 12, 13, 14, /* r0 - r7 */ | |
44 | 0, 1, 2, 3, 4, 5, 6, 7, /* r8 - r15 */ | |
45 | 23, 24, 25, 26, 27, 28, 29, 30, /* r16 - r23 */ | |
0b76b0ce | 46 | -1, -1, 19, 18, 17, 21, -1, 16, /* et bt gp sp fp ea sstatus ra */ |
a1217d97 SL |
47 | 21, /* pc */ |
48 | -1, 20, -1, -1, -1, -1, -1, -1, /* status estatus ... */ | |
49 | -1, -1, -1, -1, -1, -1, -1, -1 | |
50 | }; | |
51 | ||
c5b8d704 AA |
52 | /* General register set size. Should match sizeof (struct pt_regs) + |
53 | sizeof (struct switch_stack) from the NIOS2 Linux kernel patch. */ | |
54 | ||
55 | #define NIOS2_GREGS_SIZE (4 * 34) | |
56 | ||
a1217d97 SL |
57 | /* Implement the supply_regset hook for core files. */ |
58 | ||
59 | static void | |
60 | nios2_supply_gregset (const struct regset *regset, | |
61 | struct regcache *regcache, | |
62 | int regnum, const void *gregs_buf, size_t len) | |
63 | { | |
19ba03f4 | 64 | const gdb_byte *gregs = (const gdb_byte *) gregs_buf; |
a1217d97 SL |
65 | int regno; |
66 | static const gdb_byte zero_buf[4] = {0, 0, 0, 0}; | |
67 | ||
68 | for (regno = NIOS2_Z_REGNUM; regno <= NIOS2_MPUACC_REGNUM; regno++) | |
69 | if (regnum == -1 || regnum == regno) | |
70 | { | |
71 | if (reg_offsets[regno] != -1) | |
72 | regcache_raw_supply (regcache, regno, | |
73 | gregs + 4 * reg_offsets[regno]); | |
74 | else | |
75 | regcache_raw_supply (regcache, regno, zero_buf); | |
76 | } | |
77 | } | |
78 | ||
81580573 AA |
79 | /* Implement the collect_regset hook for core files. */ |
80 | ||
81 | static void | |
82 | nios2_collect_gregset (const struct regset *regset, | |
83 | const struct regcache *regcache, | |
84 | int regnum, void *gregs_buf, size_t len) | |
85 | { | |
19ba03f4 | 86 | gdb_byte *gregs = (gdb_byte *) gregs_buf; |
81580573 AA |
87 | int regno; |
88 | ||
89 | for (regno = NIOS2_Z_REGNUM; regno <= NIOS2_MPUACC_REGNUM; regno++) | |
90 | if (regnum == -1 || regnum == regno) | |
91 | { | |
92 | if (reg_offsets[regno] != -1) | |
93 | regcache_raw_collect (regcache, regno, | |
94 | gregs + 4 * reg_offsets[regno]); | |
95 | } | |
96 | } | |
97 | ||
3ca7dae4 | 98 | static const struct regset nios2_core_regset = |
a1217d97 SL |
99 | { |
100 | NULL, | |
101 | nios2_supply_gregset, | |
81580573 | 102 | nios2_collect_gregset |
a1217d97 SL |
103 | }; |
104 | ||
c5b8d704 | 105 | /* Iterate over core file register note sections. */ |
a1217d97 | 106 | |
c5b8d704 AA |
107 | static void |
108 | nios2_iterate_over_regset_sections (struct gdbarch *gdbarch, | |
109 | iterate_over_regset_sections_cb *cb, | |
110 | void *cb_data, | |
111 | const struct regcache *regcache) | |
a1217d97 | 112 | { |
c5b8d704 | 113 | cb (".reg", NIOS2_GREGS_SIZE, &nios2_core_regset, NULL, cb_data); |
a1217d97 SL |
114 | } |
115 | ||
a1217d97 | 116 | /* Initialize a trad-frame cache corresponding to the tramp-frame. |
35d54293 SL |
117 | FUNC is the address of the instruction TRAMP[0] in memory. |
118 | ||
119 | This ABI is not documented. It corresponds to rt_setup_ucontext in | |
120 | the kernel arch/nios2/kernel/signal.c file. | |
121 | ||
122 | The key points are: | |
123 | - The kernel creates a trampoline at the hard-wired address 0x1044. | |
124 | - The stack pointer points to an object of type struct rt_sigframe. | |
125 | The definition of this structure is not exported from the kernel. | |
126 | The register save area is located at offset 152 bytes (as determined | |
127 | by inspection of the stack contents in the debugger), and the | |
128 | registers are saved as r1-r23, ra, fp, gp, ea, sp. | |
129 | ||
130 | This interface was implemented with kernel version 3.19 (the first | |
131 | official mainline kernel). Older unofficial kernel versions used | |
132 | incompatible conventions; we do not support those here. */ | |
133 | ||
134 | #define NIOS2_SIGRETURN_TRAMP_ADDR 0x1044 | |
135 | #define NIOS2_SIGRETURN_REGSAVE_OFFSET 152 | |
a1217d97 SL |
136 | |
137 | static void | |
138 | nios2_linux_rt_sigreturn_init (const struct tramp_frame *self, | |
139 | struct frame_info *next_frame, | |
140 | struct trad_frame_cache *this_cache, | |
141 | CORE_ADDR func) | |
142 | { | |
35d54293 SL |
143 | CORE_ADDR sp = get_frame_register_unsigned (next_frame, NIOS2_SP_REGNUM); |
144 | CORE_ADDR base = sp + NIOS2_SIGRETURN_REGSAVE_OFFSET; | |
a1217d97 SL |
145 | int i; |
146 | ||
147 | for (i = 0; i < 23; i++) | |
148 | trad_frame_set_reg_addr (this_cache, i + 1, base + i * 4); | |
149 | trad_frame_set_reg_addr (this_cache, NIOS2_RA_REGNUM, base + 23 * 4); | |
150 | trad_frame_set_reg_addr (this_cache, NIOS2_FP_REGNUM, base + 24 * 4); | |
151 | trad_frame_set_reg_addr (this_cache, NIOS2_GP_REGNUM, base + 25 * 4); | |
152 | trad_frame_set_reg_addr (this_cache, NIOS2_PC_REGNUM, base + 27 * 4); | |
153 | trad_frame_set_reg_addr (this_cache, NIOS2_SP_REGNUM, base + 28 * 4); | |
154 | ||
155 | /* Save a frame ID. */ | |
156 | trad_frame_set_id (this_cache, frame_id_build (base, func)); | |
157 | } | |
158 | ||
af60a1ef SL |
159 | /* Trampoline for sigreturn. This has the form |
160 | movi r2, __NR_rt_sigreturn | |
161 | trap 0 | |
162 | appropriately encoded for R1 or R2. */ | |
163 | ||
164 | static struct tramp_frame nios2_r1_linux_rt_sigreturn_tramp_frame = | |
165 | { | |
166 | SIGTRAMP_FRAME, | |
167 | 4, | |
168 | { | |
169 | { MATCH_R1_MOVI | SET_IW_I_B (2) | SET_IW_I_IMM16 (139), -1 }, | |
170 | { MATCH_R1_TRAP | SET_IW_R_IMM5 (0), -1}, | |
171 | { TRAMP_SENTINEL_INSN } | |
172 | }, | |
173 | nios2_linux_rt_sigreturn_init | |
174 | }; | |
175 | ||
176 | static struct tramp_frame nios2_r2_linux_rt_sigreturn_tramp_frame = | |
a1217d97 SL |
177 | { |
178 | SIGTRAMP_FRAME, | |
179 | 4, | |
180 | { | |
af60a1ef SL |
181 | { MATCH_R2_MOVI | SET_IW_F2I16_B (2) | SET_IW_F2I16_IMM16 (139), -1 }, |
182 | { MATCH_R2_TRAP | SET_IW_X2L5_IMM5 (0), -1}, | |
a1217d97 SL |
183 | { TRAMP_SENTINEL_INSN } |
184 | }, | |
185 | nios2_linux_rt_sigreturn_init | |
186 | }; | |
187 | ||
188 | /* When FRAME is at a syscall instruction, return the PC of the next | |
189 | instruction to be executed. */ | |
190 | ||
191 | static CORE_ADDR | |
af60a1ef SL |
192 | nios2_linux_syscall_next_pc (struct frame_info *frame, |
193 | const struct nios2_opcode *op) | |
a1217d97 SL |
194 | { |
195 | CORE_ADDR pc = get_frame_pc (frame); | |
196 | ULONGEST syscall_nr = get_frame_register_unsigned (frame, NIOS2_R2_REGNUM); | |
197 | ||
198 | /* If we are about to make a sigreturn syscall, use the unwinder to | |
199 | decode the signal frame. */ | |
21986715 | 200 | if (syscall_nr == 139 /* rt_sigreturn */) |
a1217d97 SL |
201 | return frame_unwind_caller_pc (frame); |
202 | ||
af60a1ef | 203 | return pc + op->size; |
a1217d97 SL |
204 | } |
205 | ||
206 | /* Hook function for gdbarch_register_osabi. */ | |
207 | ||
208 | static void | |
209 | nios2_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) | |
210 | { | |
211 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); | |
212 | ||
213 | linux_init_abi (info, gdbarch); | |
214 | ||
215 | /* Shared library handling. */ | |
216 | set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target); | |
217 | set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver); | |
218 | ||
219 | set_solib_svr4_fetch_link_map_offsets (gdbarch, | |
220 | svr4_ilp32_fetch_link_map_offsets); | |
221 | /* Enable TLS support. */ | |
222 | set_gdbarch_fetch_tls_load_module_address (gdbarch, | |
223 | svr4_fetch_objfile_link_map); | |
224 | /* Core file support. */ | |
c5b8d704 AA |
225 | set_gdbarch_iterate_over_regset_sections |
226 | (gdbarch, nios2_iterate_over_regset_sections); | |
a1217d97 | 227 | /* Linux signal frame unwinders. */ |
af60a1ef SL |
228 | if (gdbarch_bfd_arch_info (gdbarch)->mach == bfd_mach_nios2r2) |
229 | tramp_frame_prepend_unwinder (gdbarch, | |
230 | &nios2_r2_linux_rt_sigreturn_tramp_frame); | |
231 | else | |
232 | tramp_frame_prepend_unwinder (gdbarch, | |
233 | &nios2_r1_linux_rt_sigreturn_tramp_frame); | |
a1217d97 SL |
234 | |
235 | tdep->syscall_next_pc = nios2_linux_syscall_next_pc; | |
236 | ||
237 | /* Index of target address word in glibc jmp_buf. */ | |
238 | tdep->jb_pc = 10; | |
239 | } | |
240 | ||
a1217d97 SL |
241 | void |
242 | _initialize_nios2_linux_tdep (void) | |
243 | { | |
8d6dbeb4 SL |
244 | |
245 | const struct bfd_arch_info *arch_info; | |
246 | ||
247 | for (arch_info = bfd_lookup_arch (bfd_arch_nios2, 0); | |
248 | arch_info != NULL; | |
249 | arch_info = arch_info->next) | |
250 | gdbarch_register_osabi (bfd_arch_nios2, arch_info->mach, | |
251 | GDB_OSABI_LINUX, nios2_linux_init_abi); | |
a1217d97 SL |
252 | |
253 | initialize_tdesc_nios2_linux (); | |
254 | } |