diff options
Diffstat (limited to 'gdb/x86-64-linux-tdep.c')
| -rw-r--r-- | gdb/x86-64-linux-tdep.c | 178 |
1 files changed, 58 insertions, 120 deletions
diff --git a/gdb/x86-64-linux-tdep.c b/gdb/x86-64-linux-tdep.c index 932e6d6..5615ebd 100644 --- a/gdb/x86-64-linux-tdep.c +++ b/gdb/x86-64-linux-tdep.c @@ -24,19 +24,21 @@ #include "defs.h" #include "inferior.h" #include "gdbcore.h" -#include "gdb_string.h" #include "regcache.h" -#include "x86-64-tdep.h" -#include "dwarf2cfi.h" #include "osabi.h" -#define LINUX_SIGTRAMP_INSN0 (0x48) /* mov $NNNNNNNN,%rax */ -#define LINUX_SIGTRAMP_OFFSET0 (0) -#define LINUX_SIGTRAMP_INSN1 (0x0f) /* syscall */ -#define LINUX_SIGTRAMP_OFFSET1 (7) +#include "gdb_string.h" -static const unsigned char linux_sigtramp_code[] = { - /* mov $__NR_rt_sigreturn,%rax */ +#include "x86-64-tdep.h" + +#define LINUX_SIGTRAMP_INSN0 0x48 /* mov $NNNNNNNN, %rax */ +#define LINUX_SIGTRAMP_OFFSET0 0 +#define LINUX_SIGTRAMP_INSN1 0x0f /* syscall */ +#define LINUX_SIGTRAMP_OFFSET1 7 + +static const unsigned char linux_sigtramp_code[] = +{ + /* mov $__NR_rt_sigreturn, %rax */ LINUX_SIGTRAMP_INSN0, 0xc7, 0xc0, 0x0f, 0x00, 0x00, 0x00, /* syscall */ LINUX_SIGTRAMP_INSN1, 0x05 @@ -51,6 +53,14 @@ static CORE_ADDR x86_64_linux_sigtramp_start (CORE_ADDR pc) { unsigned char buf[LINUX_SIGTRAMP_LEN]; + + /* We only recognize a signal trampoline if PC is at the start of + one of the two instructions. We optimize for finding the PC at + the start, as will be the case when the trampoline is not the + first frame on the stack. We assume that in the case where the + 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) return 0; @@ -71,133 +81,61 @@ x86_64_linux_sigtramp_start (CORE_ADDR pc) return pc; } -#define LINUX_SIGINFO_SIZE 0 - -/* Offset to struct sigcontext in ucontext, from <asm/ucontext.h>. */ -#define LINUX_UCONTEXT_SIGCONTEXT_OFFSET 40 - -/* Offset to saved PC in sigcontext, from <asm/sigcontext.h>. */ -#define LINUX_SIGCONTEXT_PC_OFFSET 128 -#define LINUX_SIGCONTEXT_FP_OFFSET 120 - -/* Assuming FRAME is for a GNU/Linux sigtramp routine, return the - address of the associated sigcontext structure. */ -static CORE_ADDR -x86_64_linux_sigcontext_addr (struct frame_info *frame) -{ - CORE_ADDR pc; - ULONGEST rsp; - - pc = x86_64_linux_sigtramp_start (get_frame_pc (frame)); - if (pc) - { - if (get_next_frame (frame)) - /* If this isn't the top frame, the next frame must be for the - signal handler itself. The sigcontext structure is part of - the user context. */ - return get_frame_base (get_next_frame (frame)) + LINUX_SIGINFO_SIZE + - LINUX_UCONTEXT_SIGCONTEXT_OFFSET; - - - /* This is the top frame. */ - rsp = read_register (SP_REGNUM); - return rsp + LINUX_SIGINFO_SIZE + LINUX_UCONTEXT_SIGCONTEXT_OFFSET; - - } - - error ("Couldn't recognize signal trampoline."); - return 0; -} - -/* Assuming FRAME is for a GNU/Linux sigtramp routine, return the - saved program counter. */ - -static CORE_ADDR -x86_64_linux_sigtramp_saved_pc (struct frame_info *frame) -{ - CORE_ADDR addr; - - addr = x86_64_linux_sigcontext_addr (frame); - return read_memory_integer (addr + LINUX_SIGCONTEXT_PC_OFFSET, 8); -} - -/* Immediately after a function call, return the saved pc. */ - -CORE_ADDR -x86_64_linux_saved_pc_after_call (struct frame_info *frame) -{ - if ((get_frame_type (frame) == SIGTRAMP_FRAME)) - return x86_64_linux_sigtramp_saved_pc (frame); - - return read_memory_integer (read_register (SP_REGNUM), 8); -} - -/* Saved Pc. Get it from sigcontext if within sigtramp. */ -CORE_ADDR -x86_64_linux_frame_saved_pc (struct frame_info *frame) -{ - if ((get_frame_type (frame) == SIGTRAMP_FRAME)) - return x86_64_linux_sigtramp_saved_pc (frame); - return cfi_get_ra (frame); -} - /* Return whether PC is in a GNU/Linux sigtramp routine. */ -int -x86_64_linux_in_sigtramp (CORE_ADDR pc, char *name) +static int +x86_64_linux_pc_in_sigtramp (CORE_ADDR pc, char *name) { - if (name) - return strcmp ("__restore_rt", name) == 0; - - return (x86_64_linux_sigtramp_start (pc) != 0); + /* If we have NAME, we can optimize the search. The trampoline is + named __restore_rt. However, it isn'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 (x86_64_linux_sigtramp_start (pc) != 0); + + return (strcmp ("__restore_rt", name) == 0); } -CORE_ADDR -x86_64_linux_frame_chain (struct frame_info *fi) -{ - ULONGEST addr; - CORE_ADDR fp, pc; - - if (!(get_frame_type (fi) == SIGTRAMP_FRAME)) - { - fp = cfi_frame_chain (fi); - if (fp) - return fp; - else - addr = get_frame_base (fi); - } - else - addr = get_frame_base (get_next_frame (fi)); - - addr += LINUX_SIGINFO_SIZE + LINUX_UCONTEXT_SIGCONTEXT_OFFSET; - - fp = read_memory_integer (addr + LINUX_SIGCONTEXT_FP_OFFSET, 8) + 8; +/* Offset to struct sigcontext in ucontext, from <asm/ucontext.h>. */ +#define X86_64_LINUX_UCONTEXT_SIGCONTEXT_OFFSET 40 - return fp; -} +/* Assuming NEXT_FRAME is a frame following a GNU/Linux sigtramp + routine, return the address of the associated sigcontext structure. */ -CORE_ADDR -x86_64_init_frame_pc (int fromleaf, struct frame_info *fi) +static CORE_ADDR +x86_64_linux_sigcontext_addr (struct frame_info *next_frame) { - CORE_ADDR addr; - - if (get_next_frame (fi) - && (get_frame_type (get_next_frame (fi)) == SIGTRAMP_FRAME)) - { - addr = get_frame_base (get_next_frame (get_next_frame (fi))) - + LINUX_SIGINFO_SIZE + LINUX_UCONTEXT_SIGCONTEXT_OFFSET; - return read_memory_integer (addr + LINUX_SIGCONTEXT_PC_OFFSET, 8); - } - else - return cfi_init_frame_pc (fromleaf, fi); + CORE_ADDR sp; + char buf[8]; + + frame_unwind_register (next_frame, SP_REGNUM, buf); + sp = extract_unsigned_integer (buf, 8); + + /* The sigcontext structure is part of the user context. A pointer + to the user context is passed as the third argument to the signal + handler, i.e. in %rdx. Unfortunately %rdx isn't preserved across + function calls so we can't use it. Fortunately the user context + is part of the signal frame and the unwound %rsp directly points + at it. */ + return sp + X86_64_LINUX_UCONTEXT_SIGCONTEXT_OFFSET; } static void x86_64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) { + struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); x86_64_init_abi (info, gdbarch); + + set_gdbarch_pc_in_sigtramp (gdbarch, x86_64_linux_pc_in_sigtramp); + + tdep->sigcontext_addr = x86_64_linux_sigcontext_addr; + tdep->sc_pc_offset = 16 * 8; /* From <asm/sigcontext.h>. */ + tdep->sc_sp_offset = 15 * 8; } + /* Provide a prototype to silence -Wmissing-prototypes. */ extern void _initialize_x86_64_linux_tdep (void); |