1 /* Target-dependent code for GNU/Linux on RISC-V processors.
2 Copyright (C) 2018-2024 Free Software Foundation, Inc.
4 This file is part of GDB.
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>. */
20 #include "riscv-tdep.h"
22 #include "glibc-tdep.h"
23 #include "linux-tdep.h"
24 #include "solib-svr4.h"
26 #include "tramp-frame.h"
27 #include "trad-frame.h"
30 /* The following value is derived from __NR_rt_sigreturn in
31 <include/uapi/asm-generic/unistd.h> from the Linux source tree. */
33 #define RISCV_NR_rt_sigreturn 139
35 /* Define the general register mapping. The kernel puts the PC at offset 0,
36 gdb puts it at offset 32. Register x0 is always 0 and can be ignored.
37 Registers x1 to x31 are in the same place. */
39 static const struct regcache_map_entry riscv_linux_gregmap
[] =
41 { 1, RISCV_PC_REGNUM
, 0 },
42 { 31, RISCV_RA_REGNUM
, 0 }, /* x1 to x31 */
46 /* Define the FP register mapping. The kernel puts the 32 FP regs first, and
49 static const struct regcache_map_entry riscv_linux_fregmap
[] =
51 { 32, RISCV_FIRST_FP_REGNUM
, 0 },
52 { 1, RISCV_CSR_FCSR_REGNUM
, 0 },
56 /* Define the general register regset. */
58 static const struct regset riscv_linux_gregset
=
60 riscv_linux_gregmap
, riscv_supply_regset
, regcache_collect_regset
63 /* Define the FP register regset. */
65 static const struct regset riscv_linux_fregset
=
67 riscv_linux_fregmap
, riscv_supply_regset
, regcache_collect_regset
70 /* Define hook for core file support. */
73 riscv_linux_iterate_over_regset_sections (struct gdbarch
*gdbarch
,
74 iterate_over_regset_sections_cb
*cb
,
76 const struct regcache
*regcache
)
78 cb (".reg", (32 * riscv_isa_xlen (gdbarch
)), (32 * riscv_isa_xlen (gdbarch
)),
79 &riscv_linux_gregset
, NULL
, cb_data
);
80 /* The kernel is adding 8 bytes for FCSR. */
81 cb (".reg2", (32 * riscv_isa_flen (gdbarch
)) + 8,
82 (32 * riscv_isa_flen (gdbarch
)) + 8,
83 &riscv_linux_fregset
, NULL
, cb_data
);
86 /* Signal trampoline support. */
88 static void riscv_linux_sigframe_init (const struct tramp_frame
*self
,
89 const frame_info_ptr
&this_frame
,
90 struct trad_frame_cache
*this_cache
,
93 #define RISCV_INST_LI_A7_SIGRETURN 0x08b00893
94 #define RISCV_INST_ECALL 0x00000073
96 static const struct tramp_frame riscv_linux_sigframe
= {
100 { RISCV_INST_LI_A7_SIGRETURN
, ULONGEST_MAX
},
101 { RISCV_INST_ECALL
, ULONGEST_MAX
},
102 { TRAMP_SENTINEL_INSN
}
104 riscv_linux_sigframe_init
,
108 /* Runtime signal frames look like this:
115 unsigned long __uc_flags;
116 struct ucontext *uclink;
119 char __glibc_reserved[1024 / 8 - sizeof (sigset_t)];
120 mcontext_t uc_mcontext;
123 #define SIGFRAME_SIGINFO_SIZE 128
124 #define UCONTEXT_MCONTEXT_OFFSET 176
127 riscv_linux_sigframe_init (const struct tramp_frame
*self
,
128 const frame_info_ptr
&this_frame
,
129 struct trad_frame_cache
*this_cache
,
132 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
133 int xlen
= riscv_isa_xlen (gdbarch
);
134 int flen
= riscv_isa_flen (gdbarch
);
135 CORE_ADDR frame_sp
= get_frame_sp (this_frame
);
136 CORE_ADDR mcontext_base
;
139 mcontext_base
= frame_sp
+ SIGFRAME_SIGINFO_SIZE
+ UCONTEXT_MCONTEXT_OFFSET
;
141 /* Handle the integer registers. The first one is PC, followed by x1
143 regs_base
= mcontext_base
;
144 trad_frame_set_reg_addr (this_cache
, RISCV_PC_REGNUM
, regs_base
);
145 for (int i
= 1; i
< 32; i
++)
146 trad_frame_set_reg_addr (this_cache
, RISCV_ZERO_REGNUM
+ i
,
147 regs_base
+ (i
* xlen
));
149 /* Handle the FP registers. First comes the 32 FP registers, followed by
151 regs_base
+= 32 * xlen
;
152 for (int i
= 0; i
< 32; i
++)
153 trad_frame_set_reg_addr (this_cache
, RISCV_FIRST_FP_REGNUM
+ i
,
154 regs_base
+ (i
* flen
));
155 regs_base
+= 32 * flen
;
156 trad_frame_set_reg_addr (this_cache
, RISCV_CSR_FCSR_REGNUM
, regs_base
);
158 /* Choice of the bottom of the sigframe is somewhat arbitrary. */
159 trad_frame_set_id (this_cache
, frame_id_build (frame_sp
, func
));
162 /* When FRAME is at a syscall instruction (ECALL), return the PC of the next
163 instruction to be executed. */
166 riscv_linux_syscall_next_pc (const frame_info_ptr
&frame
)
168 const CORE_ADDR pc
= get_frame_pc (frame
);
169 const ULONGEST a7
= get_frame_register_unsigned (frame
, RISCV_A7_REGNUM
);
171 if (a7
== RISCV_NR_rt_sigreturn
)
172 return frame_unwind_caller_pc (frame
);
174 return pc
+ 4 /* Length of the ECALL insn. */;
177 /* Initialize RISC-V Linux ABI info. */
180 riscv_linux_init_abi (struct gdbarch_info info
, struct gdbarch
*gdbarch
)
182 riscv_gdbarch_tdep
*tdep
= gdbarch_tdep
<riscv_gdbarch_tdep
> (gdbarch
);
184 linux_init_abi (info
, gdbarch
, 0);
186 set_gdbarch_software_single_step (gdbarch
, riscv_software_single_step
);
188 set_solib_svr4_fetch_link_map_offsets (gdbarch
,
189 (riscv_isa_xlen (gdbarch
) == 4
190 ? linux_ilp32_fetch_link_map_offsets
191 : linux_lp64_fetch_link_map_offsets
));
193 /* GNU/Linux uses SVR4-style shared libraries. */
194 set_gdbarch_skip_trampoline_code (gdbarch
, find_solib_trampoline_target
);
196 /* GNU/Linux uses the dynamic linker included in the GNU C Library. */
197 set_gdbarch_skip_solib_resolver (gdbarch
, glibc_skip_solib_resolver
);
199 /* Enable TLS support. */
200 set_gdbarch_fetch_tls_load_module_address (gdbarch
,
201 svr4_fetch_objfile_link_map
);
203 set_gdbarch_iterate_over_regset_sections
204 (gdbarch
, riscv_linux_iterate_over_regset_sections
);
206 tramp_frame_prepend_unwinder (gdbarch
, &riscv_linux_sigframe
);
208 tdep
->syscall_next_pc
= riscv_linux_syscall_next_pc
;
211 /* Initialize RISC-V Linux target support. */
213 void _initialize_riscv_linux_tdep ();
215 _initialize_riscv_linux_tdep ()
217 gdbarch_register_osabi (bfd_arch_riscv
, 0, GDB_OSABI_LINUX
,
218 riscv_linux_init_abi
);