[RFA] sighandler backtrace on x86-64

Michal Ludvig
2002-09-18T12:56:17Z

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Hi all,
the attached patch enables backtrace through signal handlers on x86-64.
It isn't yet complete, but this is the part that works.
Can someone approve it please?

Michal Ludvig
--
* SuSE CR, s.r.o * mludvig@suse.cz
* +420 2 9654 5373 * http://www.suse.cz

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2002-09-18 Michal Ludvig <mludvig@suse.cz>

* dwarf2cfi.c (struct context)
(struct context_reg): Moved to dwarf2cfi.h
(context_alloc, frame_state_alloc, context_cpy):
Made extern instead of static, removed prototypes.
* dwarf2cfi.h (struct context)
(struct context_reg): New, moved from dwarf2cfi.c
(context_alloc, frame_state_alloc, context_cpy):
New prototypes.
* x86-64-linux-tdep.c (x86_64_linux_sigtramp_saved_pc):
Changed from static to extern.
(LINUX_SIGINFO_SIZE, LINUX_SIGCONTEXT_PC_OFFSET)
(LINUX_SIGCONTEXT_FP_OFFSET)
(LINUX_UCONTEXT_SIGCONTEXT_OFFSET): Adjusted.
(x86_64_linux_in_sigtramp, x86_64_linux_frame_chain)
(x86_64_init_frame_pc, x86_64_init_extra_frame_info): New.
* x86-64-tdep.c (x86_64_gdbarch_init): Several
set_gdbarch_*() calls now use x86-64 specific functions
instead of DWARF2 CFI ones.
* x86-64-tdep.h (x86_64_linux_in_sigtramp)
(x86_64_linux_frame_chain, x86_64_init_frame_pc)
(x86_64_init_extra_frame_info): New prototypes.

Index: dwarf2cfi.c
===================================================================
RCS file: /cvs/src/src/gdb/dwarf2cfi.c,v
retrieving revision 1.16
diff -u -p -r1.16 dwarf2cfi.c
--- dwarf2cfi.c 19 Jul 2002 09:40:51 -0000 1.16
+++ dwarf2cfi.c 18 Sep 2002 11:11:02 -0000
@@ -90,37 +90,6 @@ struct fde_array
int array_size;
};

-struct context_reg
-{
- union
- {
- unsigned int reg;
- long offset;
- CORE_ADDR addr;
- }
- loc;
- enum
- {
- REG_CTX_UNSAVED,
- REG_CTX_SAVED_OFFSET,
- REG_CTX_SAVED_REG,
- REG_CTX_SAVED_ADDR,
- REG_CTX_VALUE,
- }
- how;
-};
-
-/* This is the register and unwind state for a particular frame. */
-struct context
-{
- struct context_reg *reg;
-
- CORE_ADDR cfa;
- CORE_ADDR ra;
- void *lsda;
- int args_size;
-};
-
struct frame_state_reg
{
union
@@ -208,11 +177,8 @@ static struct fde_unit *fde_unit_alloc (
static struct cie_unit *cie_unit_alloc (void);
static void fde_chunks_need_space ();

-static struct context *context_alloc ();
-static struct frame_state *frame_state_alloc ();
static void unwind_tmp_obstack_init ();
static void unwind_tmp_obstack_free ();
-static void context_cpy (struct context *dst, struct context *src);

static unsigned int read_1u (bfd * abfd, char **p);
static int read_1s (bfd * abfd, char **p);
@@ -286,7 +252,7 @@ fde_chunks_need_space (void)
}

/* Alocate a new `struct context' on temporary obstack. */
-static struct context *
+struct context *
context_alloc (void)
{
struct context *context;
@@ -303,7 +269,7 @@ context_alloc (void)
}

/* Alocate a new `struct frame_state' on temporary obstack. */
-static struct frame_state *
+struct frame_state *
frame_state_alloc (void)
{
struct frame_state *fs;
@@ -332,7 +298,7 @@ unwind_tmp_obstack_free (void)
unwind_tmp_obstack_init ();
}

-static void
+void
context_cpy (struct context *dst, struct context *src)
{
int regs_size = sizeof (struct context_reg) * NUM_REGS;
Index: dwarf2cfi.h
===================================================================
RCS file: /cvs/src/src/gdb/dwarf2cfi.h,v
retrieving revision 1.1
diff -u -p -r1.1 dwarf2cfi.h
--- dwarf2cfi.h 7 Dec 2001 12:10:15 -0000 1.1
+++ dwarf2cfi.h 18 Sep 2002 11:11:02 -0000
@@ -22,6 +22,37 @@
#ifndef DWARF2CFI_H
#define DWARF2CFI_H

+struct context_reg
+{
+ union
+ {
+ unsigned int reg;
+ long offset;
+ CORE_ADDR addr;
+ }
+ loc;
+ enum
+ {
+ REG_CTX_UNSAVED,
+ REG_CTX_SAVED_OFFSET,
+ REG_CTX_SAVED_REG,
+ REG_CTX_SAVED_ADDR,
+ REG_CTX_VALUE,
+ }
+ how;
+};
+
+/* This is the register and unwind state for a particular frame. */
+struct context
+{
+ struct context_reg *reg;
+
+ CORE_ADDR cfa;
+ CORE_ADDR ra;
+ void *lsda;
+ int args_size;
+};
+
/* Return the frame address. */
CORE_ADDR cfi_read_fp ();

@@ -63,4 +94,7 @@ void cfi_get_saved_register (char *raw_b
void cfi_virtual_frame_pointer (CORE_ADDR pc, int *frame_regnum,
LONGEST * frame_offset);

+struct context *context_alloc ();
+void context_cpy (struct context *dst, struct context *src);
+struct frame_state *frame_state_alloc ();
#endif
Index: x86-64-linux-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/x86-64-linux-tdep.c,v
retrieving revision 1.5
diff -u -p -r1.5 x86-64-linux-tdep.c
--- x86-64-linux-tdep.c 3 Sep 2002 13:06:33 -0000 1.5
+++ x86-64-linux-tdep.c 18 Sep 2002 11:11:02 -0000
@@ -35,8 +35,10 @@
#define LINUX_SIGTRAMP_OFFSET1 (7)

static const unsigned char linux_sigtramp_code[] = {
- LINUX_SIGTRAMP_INSN0, 0xc7, 0xc0, 0x89, 0x00, 0x00, 0x00, /* mov $0x89,%rax */
- LINUX_SIGTRAMP_INSN1, 0x05 /* syscall */
+ /* mov $__NR_rt_sigreturn,%rax */
+ LINUX_SIGTRAMP_INSN0, 0xc7, 0xc0, 0x0f, 0x00, 0x00, 0x00,
+ /* syscall */
+ LINUX_SIGTRAMP_INSN1, 0x05
};

#define LINUX_SIGTRAMP_LEN (sizeof linux_sigtramp_code)
@@ -68,17 +70,22 @@ x86_64_linux_sigtramp_start (CORE_ADDR p
return pc;
}

-#define LINUX_SIGINFO_SIZE 128
+#define LINUX_SIGINFO_SIZE 0

/* Offset to struct sigcontext in ucontext, from <asm/ucontext.h>. */
-#define LINUX_UCONTEXT_SIGCONTEXT_OFFSET (36)
+#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. */
-CORE_ADDR
+static CORE_ADDR
x86_64_linux_sigcontext_addr (struct frame_info *frame)
{
CORE_ADDR pc;
+ ULONGEST rsp;

pc = x86_64_linux_sigtramp_start (frame->pc);
if (pc)
@@ -92,7 +99,8 @@ x86_64_linux_sigcontext_addr (struct fra

/* This is the top frame. */
- return read_register (SP_REGNUM) + LINUX_SIGINFO_SIZE +
+ rsp = read_register (SP_REGNUM);
+ return rsp + LINUX_SIGINFO_SIZE +
LINUX_UCONTEXT_SIGCONTEXT_OFFSET;

}
@@ -101,13 +109,10 @@ x86_64_linux_sigcontext_addr (struct fra
return 0;
}

-/* Offset to saved PC in sigcontext, from <asm/sigcontext.h>. */
-#define LINUX_SIGCONTEXT_PC_OFFSET (136)
-
/* Assuming FRAME is for a GNU/Linux sigtramp routine, return the
saved program counter. */

-CORE_ADDR
+static CORE_ADDR
x86_64_linux_sigtramp_saved_pc (struct frame_info *frame)
{
CORE_ADDR addr;
@@ -134,4 +139,62 @@ x86_64_linux_frame_saved_pc (struct fram
if (frame->signal_handler_caller)
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)
+{
+ if (name)
+ return STREQ ("__restore_rt", name);
+
+ return (x86_64_linux_sigtramp_start (pc) != 0);
+}
+
+CORE_ADDR
+x86_64_linux_frame_chain (struct frame_info *fi)
+{
+ ULONGEST addr;
+ CORE_ADDR fp, pc;
+
+ if (! fi->signal_handler_caller)
+ {
+ fp = cfi_frame_chain (fi);
+ if(fp)
+ return fp;
+ else
+ addr = fi->frame;
+ }
+ else
+ addr = fi->next->frame;
+
+ addr += LINUX_SIGINFO_SIZE + LINUX_UCONTEXT_SIGCONTEXT_OFFSET;
+
+ fp = read_memory_integer (addr + LINUX_SIGCONTEXT_FP_OFFSET, 8)+8;
+
+ return fp;
+}
+
+void
+x86_64_init_frame_pc (int fromleaf, struct frame_info *fi)
+{
+ CORE_ADDR addr;
+
+ if(fi->next && fi->next->signal_handler_caller)
+ {
+ addr = fi->next->next->frame
+ + LINUX_SIGINFO_SIZE
+ + LINUX_UCONTEXT_SIGCONTEXT_OFFSET;
+ fi->pc = read_memory_integer (addr
+ + LINUX_SIGCONTEXT_PC_OFFSET, 8);
+ }
+ else
+ cfi_init_frame_pc (fromleaf, fi);
+}
+
+void
+x86_64_init_extra_frame_info (int fromleaf, struct frame_info *fi)
+{
+ cfi_init_extra_frame_info (fromleaf, fi);
}
Index: x86-64-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/x86-64-tdep.c,v
retrieving revision 1.27
diff -u -p -r1.27 x86-64-tdep.c
--- x86-64-tdep.c 12 Sep 2002 08:39:26 -0000 1.27
+++ x86-64-tdep.c 18 Sep 2002 11:11:03 -0000
@@ -1026,7 +1026,7 @@ x86_64_gdbarch_init (struct gdbarch_info

/* FRAME_CHAIN takes a frame's nominal address and produces the frame's
chain-pointer. */
- set_gdbarch_frame_chain (gdbarch, cfi_frame_chain);
+ set_gdbarch_frame_chain (gdbarch, x86_64_linux_frame_chain);

set_gdbarch_frameless_function_invocation (gdbarch,
x86_64_frameless_function_invocation);
@@ -1041,10 +1041,10 @@ x86_64_gdbarch_init (struct gdbarch_info
set_gdbarch_frame_init_saved_regs (gdbarch, x86_64_frame_init_saved_regs);

/* Frame pc initialization is handled by unwind informations. */
- set_gdbarch_init_frame_pc (gdbarch, cfi_init_frame_pc);
+ set_gdbarch_init_frame_pc (gdbarch, x86_64_init_frame_pc);

/* Initialization of unwind informations. */
- set_gdbarch_init_extra_frame_info (gdbarch, cfi_init_extra_frame_info);
+ set_gdbarch_init_extra_frame_info (gdbarch, x86_64_init_extra_frame_info);

/* Getting saved registers is handled by unwind informations. */
set_gdbarch_get_saved_register (gdbarch, cfi_get_saved_register);
@@ -1054,8 +1054,7 @@ x86_64_gdbarch_init (struct gdbarch_info
/* Cons up virtual frame pointer for trace */
set_gdbarch_virtual_frame_pointer (gdbarch, cfi_virtual_frame_pointer);

-
- set_gdbarch_frame_chain_valid (gdbarch, generic_file_frame_chain_valid);
+ set_gdbarch_frame_chain_valid (gdbarch, file_frame_chain_valid);

set_gdbarch_use_generic_dummy_frames (gdbarch, 1);
set_gdbarch_call_dummy_location (gdbarch, AT_ENTRY_POINT);
@@ -1121,6 +1120,8 @@ x86_64_gdbarch_init (struct gdbarch_info
/* Use dwarf2 debug frame informations. */
set_gdbarch_dwarf2_build_frame_info (gdbarch, dwarf2_build_frame_info);
set_gdbarch_dwarf2_reg_to_regnum (gdbarch, x86_64_dwarf2_reg_to_regnum);
+
+ set_gdbarch_pc_in_sigtramp (gdbarch, x86_64_linux_in_sigtramp);

return gdbarch;
}
Index: x86-64-tdep.h
===================================================================
RCS file: /cvs/src/src/gdb/x86-64-tdep.h,v
retrieving revision 1.5
diff -u -p -r1.5 x86-64-tdep.h
--- x86-64-tdep.h 20 Jun 2002 13:08:12 -0000 1.5
+++ x86-64-tdep.h 18 Sep 2002 11:11:03 -0000
@@ -31,8 +31,12 @@ extern int x86_64_num_gregs;
int x86_64_register_number (const char *name);
const char *x86_64_register_name (int reg_nr);

-
gdbarch_frame_saved_pc_ftype x86_64_linux_frame_saved_pc;
gdbarch_saved_pc_after_call_ftype x86_64_linux_saved_pc_after_call;
+gdbarch_pc_in_sigtramp_ftype x86_64_linux_in_sigtramp;
+CORE_ADDR x86_64_linux_frame_chain (struct frame_info *fi);
+void x86_64_init_frame_pc (int fromleaf, struct frame_info *fi);
+void x86_64_init_extra_frame_info (int fromleaf, struct frame_info *fi);
+

#endif