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386c036b MK |
1 | /* Target-dependent code for GNU/Linux SPARC. |
2 | ||
197e01b6 | 3 | Copyright (C) 2003, 2004, 2005 Free Software Foundation, Inc. |
386c036b MK |
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 2 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, write to the Free Software | |
197e01b6 EZ |
19 | Foundation, Inc., 51 Franklin Street, Fifth Floor, |
20 | Boston, MA 02110-1301, USA. */ | |
386c036b MK |
21 | |
22 | #include "defs.h" | |
faea95b1 | 23 | #include "dwarf2-frame.h" |
386c036b MK |
24 | #include "floatformat.h" |
25 | #include "frame.h" | |
26 | #include "frame-unwind.h" | |
27 | #include "gdbarch.h" | |
28 | #include "gdbcore.h" | |
29 | #include "osabi.h" | |
30 | #include "regcache.h" | |
31 | #include "solib-svr4.h" | |
32 | #include "symtab.h" | |
33 | #include "trad-frame.h" | |
70f1dc74 | 34 | #include "tramp-frame.h" |
386c036b | 35 | |
386c036b MK |
36 | #include "sparc-tdep.h" |
37 | ||
81f726ab | 38 | /* Signal trampoline support. */ |
386c036b | 39 | |
70f1dc74 MK |
40 | static void sparc32_linux_sigframe_init (const struct tramp_frame *self, |
41 | struct frame_info *next_frame, | |
42 | struct trad_frame_cache *this_cache, | |
43 | CORE_ADDR func); | |
44 | ||
386c036b MK |
45 | /* GNU/Linux has two flavors of signals. Normal signal handlers, and |
46 | "realtime" (RT) signals. The RT signals can provide additional | |
47 | information to the signal handler if the SA_SIGINFO flag is set | |
48 | when establishing a signal handler using `sigaction'. It is not | |
49 | unlikely that future versions of GNU/Linux will support SA_SIGINFO | |
50 | for normal signals too. */ | |
51 | ||
52 | /* When the sparc Linux kernel calls a signal handler and the | |
53 | SA_RESTORER flag isn't set, the return address points to a bit of | |
70f1dc74 MK |
54 | code on the stack. This code checks whether the PC appears to be |
55 | within this bit of code. | |
386c036b | 56 | |
70f1dc74 | 57 | The instruction sequence for normal signals is encoded below. |
386c036b MK |
58 | Checking for the code sequence should be somewhat reliable, because |
59 | the effect is to call the system call sigreturn. This is unlikely | |
70f1dc74 | 60 | to occur anywhere other than a signal trampoline. */ |
386c036b | 61 | |
70f1dc74 MK |
62 | static const struct tramp_frame sparc32_linux_sigframe = |
63 | { | |
81f726ab DM |
64 | SIGTRAMP_FRAME, |
65 | 4, | |
66 | { | |
70f1dc74 MK |
67 | { 0x821020d8, -1 }, /* mov __NR_sugreturn, %g1 */ |
68 | { 0x91d02010, -1 }, /* ta 0x10 */ | |
81f726ab DM |
69 | { TRAMP_SENTINEL_INSN, -1 } |
70 | }, | |
71 | sparc32_linux_sigframe_init | |
72 | }; | |
386c036b | 73 | |
70f1dc74 MK |
74 | /* The instruction sequence for RT signals is slightly different. The |
75 | effect is to call the system call rt_sigreturn. */ | |
76 | ||
77 | static const struct tramp_frame sparc32_linux_rt_sigframe = | |
78 | { | |
81f726ab DM |
79 | SIGTRAMP_FRAME, |
80 | 4, | |
81 | { | |
70f1dc74 MK |
82 | { 0x82102065, -1 }, /* mov __NR_rt_sigreturn, %g1 */ |
83 | { 0x91d02010, -1 }, /* ta 0x10 */ | |
81f726ab DM |
84 | { TRAMP_SENTINEL_INSN, -1 } |
85 | }, | |
86 | sparc32_linux_sigframe_init | |
87 | }; | |
386c036b | 88 | |
81f726ab DM |
89 | static void |
90 | sparc32_linux_sigframe_init (const struct tramp_frame *self, | |
91 | struct frame_info *next_frame, | |
92 | struct trad_frame_cache *this_cache, | |
93 | CORE_ADDR func) | |
386c036b | 94 | { |
80f9e3aa | 95 | CORE_ADDR base, addr, sp_addr; |
386c036b MK |
96 | int regnum; |
97 | ||
81f726ab DM |
98 | base = frame_unwind_register_unsigned (next_frame, SPARC_O1_REGNUM); |
99 | if (self == &sparc32_linux_rt_sigframe) | |
100 | base += 128; | |
386c036b | 101 | |
70f1dc74 | 102 | /* Offsets from <bits/sigcontext.h>. */ |
78a0fd57 | 103 | |
70f1dc74 MK |
104 | trad_frame_set_reg_addr (this_cache, SPARC32_PSR_REGNUM, base + 0); |
105 | trad_frame_set_reg_addr (this_cache, SPARC32_PC_REGNUM, base + 4); | |
106 | trad_frame_set_reg_addr (this_cache, SPARC32_NPC_REGNUM, base + 8); | |
107 | trad_frame_set_reg_addr (this_cache, SPARC32_Y_REGNUM, base + 12); | |
386c036b MK |
108 | |
109 | /* Since %g0 is always zero, keep the identity encoding. */ | |
70f1dc74 | 110 | addr = base + 20; |
80f9e3aa | 111 | sp_addr = base + 16 + ((SPARC_SP_REGNUM - SPARC_G0_REGNUM) * 4); |
81f726ab DM |
112 | for (regnum = SPARC_G1_REGNUM; regnum <= SPARC_O7_REGNUM; regnum++) |
113 | { | |
114 | trad_frame_set_reg_addr (this_cache, regnum, addr); | |
115 | addr += 4; | |
116 | } | |
386c036b | 117 | |
80f9e3aa DM |
118 | base = frame_unwind_register_unsigned (next_frame, SPARC_SP_REGNUM); |
119 | addr = get_frame_memory_unsigned (next_frame, sp_addr, 4); | |
120 | ||
81f726ab DM |
121 | for (regnum = SPARC_L0_REGNUM; regnum <= SPARC_I7_REGNUM; regnum++) |
122 | { | |
123 | trad_frame_set_reg_addr (this_cache, regnum, addr); | |
124 | addr += 4; | |
125 | } | |
126 | trad_frame_set_id (this_cache, frame_id_build (base, func)); | |
386c036b | 127 | } |
386c036b | 128 | \f |
0b4294d3 DM |
129 | /* Return the address of a system call's alternative return |
130 | address. */ | |
131 | ||
132 | static CORE_ADDR | |
133 | sparc32_linux_step_trap (unsigned long insn) | |
134 | { | |
135 | if (insn == 0x91d02010) | |
136 | { | |
137 | ULONGEST sc_num; | |
138 | ||
139 | regcache_cooked_read_unsigned (current_regcache, | |
140 | SPARC_G1_REGNUM, &sc_num); | |
141 | ||
142 | /* __NR_rt_sigreturn is 101 and __NR_sigreturn is 216 */ | |
143 | if (sc_num == 101 || sc_num == 216) | |
144 | { | |
145 | ULONGEST sp, pc_offset; | |
146 | ||
147 | regcache_cooked_read_unsigned (current_regcache, | |
148 | SPARC_SP_REGNUM, &sp); | |
149 | ||
150 | /* The kernel puts the sigreturn registers on the stack, | |
151 | and this is where the signal unwinding state is take from | |
152 | when returning from a signal. | |
153 | ||
154 | For __NR_sigreturn, this register area sits 96 bytes from | |
155 | the base of the stack. The saved PC sits 4 bytes into the | |
156 | sigreturn register save area. | |
157 | ||
158 | For __NR_rt_sigreturn a siginfo_t, which is 128 bytes, sits | |
159 | right before the sigreturn register save area. */ | |
160 | ||
161 | pc_offset = 96 + 4; | |
162 | if (sc_num == 101) | |
163 | pc_offset += 128; | |
164 | ||
165 | return read_memory_unsigned_integer (sp + pc_offset, 4); | |
166 | } | |
167 | } | |
168 | ||
169 | return 0; | |
170 | } | |
171 | \f | |
386c036b | 172 | |
386c036b MK |
173 | static void |
174 | sparc32_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) | |
175 | { | |
a33e488c MK |
176 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
177 | ||
81f726ab DM |
178 | tramp_frame_prepend_unwinder (gdbarch, &sparc32_linux_sigframe); |
179 | tramp_frame_prepend_unwinder (gdbarch, &sparc32_linux_rt_sigframe); | |
180 | ||
a33e488c MK |
181 | /* GNU/Linux has SVR4-style shared libraries... */ |
182 | set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target); | |
183 | set_solib_svr4_fetch_link_map_offsets | |
184 | (gdbarch, svr4_ilp32_fetch_link_map_offsets); | |
386c036b | 185 | |
a33e488c MK |
186 | /* ...which means that we need some special handling when doing |
187 | prologue analysis. */ | |
188 | tdep->plt_entry_size = 12; | |
386c036b MK |
189 | |
190 | /* GNU/Linux doesn't support the 128-bit `long double' from the psABI. */ | |
191 | set_gdbarch_long_double_bit (gdbarch, 64); | |
192 | set_gdbarch_long_double_format (gdbarch, &floatformat_ieee_double_big); | |
193 | ||
b2756930 KB |
194 | /* Enable TLS support. */ |
195 | set_gdbarch_fetch_tls_load_module_address (gdbarch, | |
196 | svr4_fetch_objfile_link_map); | |
faea95b1 | 197 | |
0b4294d3 DM |
198 | /* Make sure we can single-step over signal return system calls. */ |
199 | tdep->step_trap = sparc32_linux_step_trap; | |
200 | ||
faea95b1 DM |
201 | /* Hook in the DWARF CFI frame unwinder. */ |
202 | frame_unwind_append_sniffer (gdbarch, dwarf2_frame_sniffer); | |
386c036b MK |
203 | } |
204 | ||
205 | /* Provide a prototype to silence -Wmissing-prototypes. */ | |
206 | extern void _initialize_sparc_linux_tdep (void); | |
207 | ||
208 | void | |
209 | _initialize_sparc_linux_tdep (void) | |
210 | { | |
211 | gdbarch_register_osabi (bfd_arch_sparc, 0, GDB_OSABI_LINUX, | |
212 | sparc32_linux_init_abi); | |
213 | } |