diff options
Diffstat (limited to 'gdb/i386-linux-tdep.c')
| -rw-r--r-- | gdb/i386-linux-tdep.c | 56 |
1 files changed, 30 insertions, 26 deletions
diff --git a/gdb/i386-linux-tdep.c b/gdb/i386-linux-tdep.c index e177d59d75d..f42f6b7bddf 100644 --- a/gdb/i386-linux-tdep.c +++ b/gdb/i386-linux-tdep.c @@ -83,13 +83,13 @@ i386_linux_register_reggroup_p (struct gdbarch *gdbarch, int regnum, Checking for the code sequence should be somewhat reliable, because the effect is to call the system call sigreturn. This is unlikely - to occur anywhere other than a signal trampoline. + to occur anywhere other than in a signal trampoline. It kind of sucks that we have to read memory from the process in order to identify a signal trampoline, but there doesn't seem to be - any other way. The DEPRECATED_PC_IN_SIGTRAMP macro in tm-linux.h - arranges to only call us if no function name could be identified, - which should be the case since the code is on the stack. + any other way. Therefore we only do the memory reads if no + function name could be identified, which should be the case since + the code is on the stack. Detection of signal trampolines for handlers that set the SA_RESTORER flag is in general not possible. Unfortunately this is @@ -115,12 +115,13 @@ static const unsigned char linux_sigtramp_code[] = #define LINUX_SIGTRAMP_LEN (sizeof linux_sigtramp_code) -/* If PC is in a sigtramp routine, return the address of the start of - the routine. Otherwise, return 0. */ +/* If NEXT_FRAME unwinds into a sigtramp routine, return the address + of the start of the routine. Otherwise, return 0. */ static CORE_ADDR -i386_linux_sigtramp_start (CORE_ADDR pc) +i386_linux_sigtramp_start (struct frame_info *next_frame) { + CORE_ADDR pc = frame_pc_unwind (next_frame); unsigned char buf[LINUX_SIGTRAMP_LEN]; /* We only recognize a signal trampoline if PC is at the start of @@ -130,7 +131,7 @@ i386_linux_sigtramp_start (CORE_ADDR pc) PC is not at the start of the instruction sequence, there will be a few trailing readable bytes on the stack. */ - if (read_memory_nobpt (pc, (char *) buf, LINUX_SIGTRAMP_LEN) != 0) + if (!safe_frame_unwind_memory (next_frame, pc, buf, LINUX_SIGTRAMP_LEN)) return 0; if (buf[0] != LINUX_SIGTRAMP_INSN0) @@ -151,7 +152,7 @@ i386_linux_sigtramp_start (CORE_ADDR pc) pc -= adjust; - if (read_memory_nobpt (pc, (char *) buf, LINUX_SIGTRAMP_LEN) != 0) + if (!safe_frame_unwind_memory (next_frame, pc, buf, LINUX_SIGTRAMP_LEN)) return 0; } @@ -182,12 +183,13 @@ static const unsigned char linux_rt_sigtramp_code[] = #define LINUX_RT_SIGTRAMP_LEN (sizeof linux_rt_sigtramp_code) -/* If PC is in a RT sigtramp routine, return the address of the start - of the routine. Otherwise, return 0. */ +/* If NEXT_FRAME unwinds into an RT sigtramp routine, return the + address of the start of the routine. Otherwise, return 0. */ static CORE_ADDR -i386_linux_rt_sigtramp_start (CORE_ADDR pc) +i386_linux_rt_sigtramp_start (struct frame_info *next_frame) { + CORE_ADDR pc = frame_pc_unwind (next_frame); unsigned char buf[LINUX_RT_SIGTRAMP_LEN]; /* We only recognize a signal trampoline if PC is at the start of @@ -197,7 +199,7 @@ i386_linux_rt_sigtramp_start (CORE_ADDR pc) PC is not at the start of the instruction sequence, there will be a few trailing readable bytes on the stack. */ - if (read_memory_nobpt (pc, (char *) buf, LINUX_RT_SIGTRAMP_LEN) != 0) + if (!safe_frame_unwind_memory (next_frame, pc, buf, LINUX_RT_SIGTRAMP_LEN)) return 0; if (buf[0] != LINUX_RT_SIGTRAMP_INSN0) @@ -207,7 +209,8 @@ i386_linux_rt_sigtramp_start (CORE_ADDR pc) pc -= LINUX_RT_SIGTRAMP_OFFSET1; - if (read_memory_nobpt (pc, (char *) buf, LINUX_RT_SIGTRAMP_LEN) != 0) + if (!safe_frame_unwind_memory (next_frame, pc, buf, + LINUX_RT_SIGTRAMP_LEN)) return 0; } @@ -217,19 +220,25 @@ i386_linux_rt_sigtramp_start (CORE_ADDR pc) return pc; } -/* Return whether PC is in a GNU/Linux sigtramp routine. */ +/* Return whether the frame preceding NEXT_FRAME corresponds to a + GNU/Linux sigtramp routine. */ static int -i386_linux_pc_in_sigtramp (CORE_ADDR pc, char *name) +i386_linux_sigtramp_p (struct frame_info *next_frame) { + CORE_ADDR pc = frame_pc_unwind (next_frame); + char *name; + + find_pc_partial_function (pc, &name, NULL, NULL); + /* If we have NAME, we can optimize the search. The trampolines are named __restore and __restore_rt. However, they aren't dynamically exported from the shared C library, so the trampoline may appear to be part of the preceding function. This should always be sigaction, __sigaction, or __libc_sigaction (all aliases to the same function). */ if (name == NULL || strstr (name, "sigaction") != NULL) - return (i386_linux_sigtramp_start (pc) != 0 - || i386_linux_rt_sigtramp_start (pc) != 0); + return (i386_linux_sigtramp_start (next_frame) != 0 + || i386_linux_rt_sigtramp_start (next_frame) != 0); return (strcmp ("__restore", name) == 0 || strcmp ("__restore_rt", name) == 0); @@ -251,7 +260,7 @@ i386_linux_sigcontext_addr (struct frame_info *next_frame) frame_unwind_register (next_frame, I386_ESP_REGNUM, buf); sp = extract_unsigned_integer (buf, 4); - pc = i386_linux_sigtramp_start (frame_pc_unwind (next_frame)); + pc = i386_linux_sigtramp_start (next_frame); if (pc) { /* The sigcontext structure lives on the stack, right after @@ -265,7 +274,7 @@ i386_linux_sigcontext_addr (struct frame_info *next_frame) return sp; } - pc = i386_linux_rt_sigtramp_start (frame_pc_unwind (next_frame)); + pc = i386_linux_rt_sigtramp_start (next_frame); if (pc) { CORE_ADDR ucontext_addr; @@ -394,16 +403,11 @@ i386_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) tdep->jb_pc_offset = 20; /* From <bits/setjmp.h>. */ + tdep->sigtramp_p = i386_linux_sigtramp_p; tdep->sigcontext_addr = i386_linux_sigcontext_addr; tdep->sc_reg_offset = i386_linux_sc_reg_offset; tdep->sc_num_regs = ARRAY_SIZE (i386_linux_sc_reg_offset); - /* When the i386 Linux kernel calls a signal handler, the return - address points to a bit of code on the stack. This function is - used to identify this bit of code as a signal trampoline in order - to support backtracing through calls to signal handlers. */ - set_gdbarch_deprecated_pc_in_sigtramp (gdbarch, i386_linux_pc_in_sigtramp); - /* GNU/Linux uses SVR4-style shared libraries. */ set_solib_svr4_fetch_link_map_offsets (gdbarch, svr4_ilp32_fetch_link_map_offsets); |