1 /* Target-dependent code for GNU/Linux SPARC.
3 Copyright (C) 2003, 2004, 2005 Free Software Foundation, Inc.
5 This file is part of GDB.
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.
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.
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
19 Foundation, Inc., 51 Franklin Street, Fifth Floor,
20 Boston, MA 02110-1301, USA. */
23 #include "dwarf2-frame.h"
24 #include "floatformat.h"
26 #include "frame-unwind.h"
31 #include "solib-svr4.h"
33 #include "trad-frame.h"
34 #include "tramp-frame.h"
36 #include "sparc-tdep.h"
38 /* Signal trampoline support. */
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,
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. */
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
54 code on the stack. This code checks whether the PC appears to be
55 within this bit of code.
57 The instruction sequence for normal signals is encoded below.
58 Checking for the code sequence should be somewhat reliable, because
59 the effect is to call the system call sigreturn. This is unlikely
60 to occur anywhere other than a signal trampoline. */
62 static const struct tramp_frame sparc32_linux_sigframe =
67 { 0x821020d8, -1 }, /* mov __NR_sugreturn, %g1 */
68 { 0x91d02010, -1 }, /* ta 0x10 */
69 { TRAMP_SENTINEL_INSN, -1 }
71 sparc32_linux_sigframe_init
74 /* The instruction sequence for RT signals is slightly different. The
75 effect is to call the system call rt_sigreturn. */
77 static const struct tramp_frame sparc32_linux_rt_sigframe =
82 { 0x82102065, -1 }, /* mov __NR_rt_sigreturn, %g1 */
83 { 0x91d02010, -1 }, /* ta 0x10 */
84 { TRAMP_SENTINEL_INSN, -1 }
86 sparc32_linux_sigframe_init
90 sparc32_linux_sigframe_init (const struct tramp_frame *self,
91 struct frame_info *next_frame,
92 struct trad_frame_cache *this_cache,
95 CORE_ADDR base, addr, sp_addr;
98 base = frame_unwind_register_unsigned (next_frame, SPARC_O1_REGNUM);
99 if (self == &sparc32_linux_rt_sigframe)
102 /* Offsets from <bits/sigcontext.h>. */
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);
109 /* Since %g0 is always zero, keep the identity encoding. */
111 sp_addr = base + 16 + ((SPARC_SP_REGNUM - SPARC_G0_REGNUM) * 4);
112 for (regnum = SPARC_G1_REGNUM; regnum <= SPARC_O7_REGNUM; regnum++)
114 trad_frame_set_reg_addr (this_cache, regnum, addr);
118 base = frame_unwind_register_unsigned (next_frame, SPARC_SP_REGNUM);
119 addr = get_frame_memory_unsigned (next_frame, sp_addr, 4);
121 for (regnum = SPARC_L0_REGNUM; regnum <= SPARC_I7_REGNUM; regnum++)
123 trad_frame_set_reg_addr (this_cache, regnum, addr);
126 trad_frame_set_id (this_cache, frame_id_build (base, func));
129 /* Return the address of a system call's alternative return
133 sparc32_linux_step_trap (unsigned long insn)
135 if (insn == 0x91d02010)
139 regcache_cooked_read_unsigned (current_regcache,
140 SPARC_G1_REGNUM, &sc_num);
142 /* __NR_rt_sigreturn is 101 and __NR_sigreturn is 216 */
143 if (sc_num == 101 || sc_num == 216)
145 ULONGEST sp, pc_offset;
147 regcache_cooked_read_unsigned (current_regcache,
148 SPARC_SP_REGNUM, &sp);
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.
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.
158 For __NR_rt_sigreturn a siginfo_t, which is 128 bytes, sits
159 right before the sigreturn register save area. */
165 return read_memory_unsigned_integer (sp + pc_offset, 4);
174 sparc32_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
176 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
178 tramp_frame_prepend_unwinder (gdbarch, &sparc32_linux_sigframe);
179 tramp_frame_prepend_unwinder (gdbarch, &sparc32_linux_rt_sigframe);
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);
186 /* ...which means that we need some special handling when doing
187 prologue analysis. */
188 tdep->plt_entry_size = 12;
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);
194 /* Enable TLS support. */
195 set_gdbarch_fetch_tls_load_module_address (gdbarch,
196 svr4_fetch_objfile_link_map);
198 /* Make sure we can single-step over signal return system calls. */
199 tdep->step_trap = sparc32_linux_step_trap;
201 /* Hook in the DWARF CFI frame unwinder. */
202 frame_unwind_append_sniffer (gdbarch, dwarf2_frame_sniffer);
205 /* Provide a prototype to silence -Wmissing-prototypes. */
206 extern void _initialize_sparc_linux_tdep (void);
209 _initialize_sparc_linux_tdep (void)
211 gdbarch_register_osabi (bfd_arch_sparc, 0, GDB_OSABI_LINUX,
212 sparc32_linux_init_abi);