diff options
Diffstat (limited to 'gdb/sparc-linux-tdep.c')
| -rw-r--r-- | gdb/sparc-linux-tdep.c | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/gdb/sparc-linux-tdep.c b/gdb/sparc-linux-tdep.c index ef7f370..446f05e 100644 --- a/gdb/sparc-linux-tdep.c +++ b/gdb/sparc-linux-tdep.c @@ -126,6 +126,49 @@ sparc32_linux_sigframe_init (const struct tramp_frame *self, trad_frame_set_id (this_cache, frame_id_build (base, func)); } +/* Return the address of a system call's alternative return + address. */ + +static CORE_ADDR +sparc32_linux_step_trap (unsigned long insn) +{ + if (insn == 0x91d02010) + { + ULONGEST sc_num; + + regcache_cooked_read_unsigned (current_regcache, + SPARC_G1_REGNUM, &sc_num); + + /* __NR_rt_sigreturn is 101 and __NR_sigreturn is 216 */ + if (sc_num == 101 || sc_num == 216) + { + ULONGEST sp, pc_offset; + + regcache_cooked_read_unsigned (current_regcache, + SPARC_SP_REGNUM, &sp); + + /* The kernel puts the sigreturn registers on the stack, + and this is where the signal unwinding state is take from + when returning from a signal. + + For __NR_sigreturn, this register area sits 96 bytes from + the base of the stack. The saved PC sits 4 bytes into the + sigreturn register save area. + + For __NR_rt_sigreturn a siginfo_t, which is 128 bytes, sits + right before the sigreturn register save area. */ + + pc_offset = 96 + 4; + if (sc_num == 101) + pc_offset += 128; + + return read_memory_unsigned_integer (sp + pc_offset, 4); + } + } + + return 0; +} + static void sparc32_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) @@ -152,6 +195,9 @@ sparc32_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) set_gdbarch_fetch_tls_load_module_address (gdbarch, svr4_fetch_objfile_link_map); + /* Make sure we can single-step over signal return system calls. */ + tdep->step_trap = sparc32_linux_step_trap; + /* Hook in the DWARF CFI frame unwinder. */ frame_unwind_append_sniffer (gdbarch, dwarf2_frame_sniffer); } |