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nios2-linux-tdep.c
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1/* Target-dependent code for GNU/Linux on Nios II.
2 Copyright (C) 2012-2023 Free Software Foundation, Inc.
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"
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#include "gdbarch.h"
33
34/* Core file and register set support. */
35
36/* Map from the normal register enumeration order to the order that
37 registers appear in core files, which corresponds to the order
38 of the register slots in the kernel's struct pt_regs. */
39
40static const int reg_offsets[NIOS2_NUM_REGS] =
41{
42 -1, 8, 9, 10, 11, 12, 13, 14, /* r0 - r7 */
43 0, 1, 2, 3, 4, 5, 6, 7, /* r8 - r15 */
44 23, 24, 25, 26, 27, 28, 29, 30, /* r16 - r23 */
45 -1, -1, 19, 18, 17, 21, -1, 16, /* et bt gp sp fp ea sstatus ra */
46 21, /* pc */
47 -1, 20, -1, -1, -1, -1, -1, -1, /* status estatus ... */
48 -1, -1, -1, -1, -1, -1, -1, -1
49};
50
51/* General register set size. Should match sizeof (struct pt_regs) +
52 sizeof (struct switch_stack) from the NIOS2 Linux kernel patch. */
53
54#define NIOS2_GREGS_SIZE (4 * 34)
55
56/* Implement the supply_regset hook for core files. */
57
58static void
60 struct regcache *regcache,
61 int regnum, const void *gregs_buf, size_t len)
62{
63 const gdb_byte *gregs = (const gdb_byte *) gregs_buf;
64 int regno;
65 static const gdb_byte zero_buf[4] = {0, 0, 0, 0};
66
67 for (regno = NIOS2_Z_REGNUM; regno <= NIOS2_MPUACC_REGNUM; regno++)
68 if (regnum == -1 || regnum == regno)
69 {
70 if (reg_offsets[regno] != -1)
71 regcache->raw_supply (regno, gregs + 4 * reg_offsets[regno]);
72 else
73 regcache->raw_supply (regno, zero_buf);
74 }
75}
76
77/* Implement the collect_regset hook for core files. */
78
79static void
81 const struct regcache *regcache,
82 int regnum, void *gregs_buf, size_t len)
83{
84 gdb_byte *gregs = (gdb_byte *) gregs_buf;
85 int regno;
86
87 for (regno = NIOS2_Z_REGNUM; regno <= NIOS2_MPUACC_REGNUM; regno++)
88 if (regnum == -1 || regnum == regno)
89 {
90 if (reg_offsets[regno] != -1)
91 regcache->raw_collect (regno, gregs + 4 * reg_offsets[regno]);
92 }
93}
94
95static const struct regset nios2_core_regset =
96{
97 NULL,
100};
101
102/* Iterate over core file register note sections. */
103
104static void
107 void *cb_data,
108 const struct regcache *regcache)
109{
111 cb_data);
112}
113
114/* Initialize a trad-frame cache corresponding to the tramp-frame.
115 FUNC is the address of the instruction TRAMP[0] in memory.
116
117 This ABI is not documented. It corresponds to rt_setup_ucontext in
118 the kernel arch/nios2/kernel/signal.c file.
119
120 The key points are:
121 - The kernel creates a trampoline at the hard-wired address 0x1044.
122 - The stack pointer points to an object of type struct rt_sigframe.
123 The definition of this structure is not exported from the kernel.
124 The register save area is located at offset 152 bytes (as determined
125 by inspection of the stack contents in the debugger), and the
126 registers are saved as r1-r23, ra, fp, gp, ea, sp.
127
128 This interface was implemented with kernel version 3.19 (the first
129 official mainline kernel). Older unofficial kernel versions used
130 incompatible conventions; we do not support those here. */
131
132#define NIOS2_SIGRETURN_TRAMP_ADDR 0x1044
133#define NIOS2_SIGRETURN_REGSAVE_OFFSET 152
134
135static void
137 frame_info_ptr next_frame,
138 struct trad_frame_cache *this_cache,
139 CORE_ADDR func)
140{
141 CORE_ADDR sp = get_frame_register_unsigned (next_frame, NIOS2_SP_REGNUM);
142 CORE_ADDR base = sp + NIOS2_SIGRETURN_REGSAVE_OFFSET;
143 int i;
144
145 for (i = 0; i < 23; i++)
146 trad_frame_set_reg_addr (this_cache, i + 1, base + i * 4);
147 trad_frame_set_reg_addr (this_cache, NIOS2_RA_REGNUM, base + 23 * 4);
148 trad_frame_set_reg_addr (this_cache, NIOS2_FP_REGNUM, base + 24 * 4);
149 trad_frame_set_reg_addr (this_cache, NIOS2_GP_REGNUM, base + 25 * 4);
150 trad_frame_set_reg_addr (this_cache, NIOS2_PC_REGNUM, base + 27 * 4);
151 trad_frame_set_reg_addr (this_cache, NIOS2_SP_REGNUM, base + 28 * 4);
152
153 /* Save a frame ID. */
154 trad_frame_set_id (this_cache, frame_id_build (base, func));
155}
156
157/* Trampoline for sigreturn. This has the form
158 movi r2, __NR_rt_sigreturn
159 trap 0
160 appropriately encoded for R1 or R2. */
161
163{
165 4,
166 {
167 { MATCH_R1_MOVI | SET_IW_I_B (2) | SET_IW_I_IMM16 (139), ULONGEST_MAX },
168 { MATCH_R1_TRAP | SET_IW_R_IMM5 (0), ULONGEST_MAX},
170 },
172};
173
175{
177 4,
178 {
179 { MATCH_R2_MOVI | SET_IW_F2I16_B (2) | SET_IW_F2I16_IMM16 (139), ULONGEST_MAX },
180 { MATCH_R2_TRAP | SET_IW_X2L5_IMM5 (0), ULONGEST_MAX},
182 },
184};
185
186/* When FRAME is at a syscall instruction, return the PC of the next
187 instruction to be executed. */
188
189static CORE_ADDR
191 const struct nios2_opcode *op)
192{
193 CORE_ADDR pc = get_frame_pc (frame);
194 ULONGEST syscall_nr = get_frame_register_unsigned (frame, NIOS2_R2_REGNUM);
195
196 /* If we are about to make a sigreturn syscall, use the unwinder to
197 decode the signal frame. */
198 if (syscall_nr == 139 /* rt_sigreturn */)
199 return frame_unwind_caller_pc (frame);
200
201 return pc + op->size;
202}
203
204/* Return true if PC is a kernel helper, a function mapped by the kernel
205 into user space on an unwritable page. Currently the only such function
206 is __kuser_cmpxchg at 0x1004. See arch/nios2/kernel/entry.S in the Linux
207 kernel sources and sysdeps/unix/sysv/linux/nios2/atomic-machine.h in
208 GLIBC. */
209static bool
211{
212 return pc == 0x1004;
213}
214
215/* Hook function for gdbarch_register_osabi. */
216
217static void
219{
220 nios2_gdbarch_tdep *tdep = gdbarch_tdep<nios2_gdbarch_tdep> (gdbarch);
221
222 linux_init_abi (info, gdbarch, 0);
223
224 /* Shared library handling. */
227
230 /* Enable TLS support. */
233 /* Core file support. */
236 /* Linux signal frame unwinders. */
237 if (gdbarch_bfd_arch_info (gdbarch)->mach == bfd_mach_nios2r2)
240 else
243
246
247 /* Index of target address word in glibc jmp_buf. */
248 tdep->jb_pc = 10;
249}
250
252void
254{
255
256 const struct bfd_arch_info *arch_info;
257
258 for (arch_info = bfd_lookup_arch (bfd_arch_nios2, 0);
259 arch_info != NULL;
260 arch_info = arch_info->next)
261 gdbarch_register_osabi (bfd_arch_nios2, arch_info->mach,
263}
int regnum
void raw_collect(int regnum, void *buf) const override
Definition regcache.c:1127
void raw_supply(int regnum, const void *buf) override
Definition regcache.c:1062
ULONGEST get_frame_register_unsigned(frame_info_ptr frame, int regnum)
Definition frame.c:1399
CORE_ADDR frame_unwind_caller_pc(frame_info_ptr this_frame)
Definition frame.c:1042
CORE_ADDR get_frame_pc(frame_info_ptr frame)
Definition frame.c:2712
struct frame_id frame_id_build(CORE_ADDR stack_addr, CORE_ADDR code_addr)
Definition frame.c:736
@ SIGTRAMP_FRAME
Definition frame.h:198
void set_gdbarch_skip_trampoline_code(struct gdbarch *gdbarch, gdbarch_skip_trampoline_code_ftype *skip_trampoline_code)
void set_gdbarch_fetch_tls_load_module_address(struct gdbarch *gdbarch, gdbarch_fetch_tls_load_module_address_ftype *fetch_tls_load_module_address)
const struct bfd_arch_info * gdbarch_bfd_arch_info(struct gdbarch *gdbarch)
Definition gdbarch.c:1387
void set_gdbarch_skip_solib_resolver(struct gdbarch *gdbarch, gdbarch_skip_solib_resolver_ftype *skip_solib_resolver)
void set_gdbarch_iterate_over_regset_sections(struct gdbarch *gdbarch, gdbarch_iterate_over_regset_sections_ftype *iterate_over_regset_sections)
void iterate_over_regset_sections_cb(const char *sect_name, int supply_size, int collect_size, const struct regset *regset, const char *human_name, void *cb_data)
Definition gdbarch.h:104
CORE_ADDR glibc_skip_solib_resolver(struct gdbarch *gdbarch, CORE_ADDR pc)
Definition glibc-tdep.c:38
link_map_offsets * linux_ilp32_fetch_link_map_offsets()
void linux_init_abi(struct gdbarch_info info, struct gdbarch *gdbarch, int num_disp_step_buffers)
CORE_ADDR find_solib_trampoline_target(frame_info_ptr frame, CORE_ADDR pc)
Definition minsyms.c:1554
static const int reg_offsets[NIOS2_NUM_REGS]
static void nios2_collect_gregset(const struct regset *regset, const struct regcache *regcache, int regnum, void *gregs_buf, size_t len)
static bool nios2_linux_is_kernel_helper(CORE_ADDR pc)
static struct tramp_frame nios2_r2_linux_rt_sigreturn_tramp_frame
static void nios2_linux_init_abi(struct gdbarch_info info, struct gdbarch *gdbarch)
static void nios2_iterate_over_regset_sections(struct gdbarch *gdbarch, iterate_over_regset_sections_cb *cb, void *cb_data, const struct regcache *regcache)
#define NIOS2_SIGRETURN_REGSAVE_OFFSET
static void nios2_supply_gregset(const struct regset *regset, struct regcache *regcache, int regnum, const void *gregs_buf, size_t len)
void _initialize_nios2_linux_tdep()
static struct tramp_frame nios2_r1_linux_rt_sigreturn_tramp_frame
static void nios2_linux_rt_sigreturn_init(const struct tramp_frame *self, frame_info_ptr next_frame, struct trad_frame_cache *this_cache, CORE_ADDR func)
static const struct regset nios2_core_regset
#define NIOS2_GREGS_SIZE
static CORE_ADDR nios2_linux_syscall_next_pc(frame_info_ptr frame, const struct nios2_opcode *op)
#define NIOS2_MPUACC_REGNUM
Definition nios2-tdep.h:58
#define NIOS2_FP_REGNUM
Definition nios2-tdep.h:37
#define NIOS2_Z_REGNUM
Definition nios2-tdep.h:29
#define NIOS2_RA_REGNUM
Definition nios2-tdep.h:40
#define NIOS2_R2_REGNUM
Definition nios2-tdep.h:30
#define NIOS2_PC_REGNUM
Definition nios2-tdep.h:41
#define NIOS2_SP_REGNUM
Definition nios2-tdep.h:36
#define NIOS2_GP_REGNUM
Definition nios2-tdep.h:35
#define NIOS2_NUM_REGS
Definition nios2-tdep.h:65
void gdbarch_register_osabi(enum bfd_architecture arch, unsigned long machine, enum gdb_osabi osabi, void(*init_osabi)(struct gdbarch_info, struct gdbarch *))
Definition osabi.c:146
@ GDB_OSABI_LINUX
Definition osabi.h:32
void(* func)(remote_target *remote, char *)
void set_solib_svr4_fetch_link_map_offsets(struct gdbarch *gdbarch, struct link_map_offsets *(*flmo)(void))
CORE_ADDR svr4_fetch_objfile_link_map(struct objfile *objfile)
CORE_ADDR(* syscall_next_pc)(frame_info_ptr frame, const struct nios2_opcode *op)
Definition nios2-tdep.h:76
bool(* is_kernel_helper)(CORE_ADDR pc)
Definition nios2-tdep.h:80
void trad_frame_set_reg_addr(struct trad_frame_cache *this_trad_cache, int regnum, CORE_ADDR addr)
Definition trad-frame.c:110
void trad_frame_set_id(struct trad_frame_cache *this_trad_cache, struct frame_id this_id)
Definition trad-frame.c:220
void tramp_frame_prepend_unwinder(struct gdbarch *gdbarch, const struct tramp_frame *tramp_frame)
#define TRAMP_SENTINEL_INSN
Definition tramp-frame.h:44