* config/m68k/tm-linux.h (FRAME_SAVED_PC): Define as

	m68k_linux_frame_saved_pc.
	(IN_SIGTRAMP): Define as m68k_linux_in_sigtramp instead of
	in_sigtramp.
	(SIGCONTEXT_PC_OFFSET): Remove.
	* m68klinux-nat.c (m68k_linux_frame_saved_pc,
	m68k_linux_sigtramp_saved_pc): New functions.
	(IS_SIGTRAMP, IS_RT_SIGTRAMP): Define.
	(SIGCONTEXT_PC_OFFSET): Moved here from config/m68k/tm-linux.h.
	(UCONTEXT_PC_OFFSET): Define.
	(m68k_linux_in_sigtramp): Renamed from in_sigtramp, handle both
	non-RT and RT signal trampolines.

3 files changed, 101 insertions, 31 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 6d536cb..a48f90d 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,18 @@
+2002-02-26  Andreas Schwab  <schwab@suse.de>
+
+	* config/m68k/tm-linux.h (FRAME_SAVED_PC): Define as
+	m68k_linux_frame_saved_pc.
+	(IN_SIGTRAMP): Define as m68k_linux_in_sigtramp instead of
+	in_sigtramp.
+	(SIGCONTEXT_PC_OFFSET): Remove.
+	* m68klinux-nat.c (m68k_linux_frame_saved_pc,
+	m68k_linux_sigtramp_saved_pc): New functions.
+	(IS_SIGTRAMP, IS_RT_SIGTRAMP): Define.
+	(SIGCONTEXT_PC_OFFSET): Moved here from config/m68k/tm-linux.h.
+	(UCONTEXT_PC_OFFSET): Define.
+	(m68k_linux_in_sigtramp): Renamed from in_sigtramp, handle both
+	non-RT and RT signal trampolines.
+
 2002-02-26  Richard Earnshaw  <rearnsha@arm.com>
 
 	* config/arm/tm-embed.h (TARGET_UPAGES): Delete.
diff --git a/gdb/config/m68k/tm-linux.h b/gdb/config/m68k/tm-linux.h
index 78e732c..94b2c2c 100644
--- a/gdb/config/m68k/tm-linux.h
+++ b/gdb/config/m68k/tm-linux.h
@@ -99,16 +99,9 @@
 
 #define GET_LONGJMP_TARGET(ADDR) m68k_get_longjmp_target(ADDR)
 
-/* Offset to saved PC in sigcontext, from <asm/sigcontext.h>.  */
-#define SIGCONTEXT_PC_OFFSET 26
-
 #undef FRAME_SAVED_PC
-#define FRAME_SAVED_PC(FRAME) \
-  (((FRAME)->signal_handler_caller \
-    ? sigtramp_saved_pc (FRAME) \
-    : read_memory_integer ((FRAME)->frame + 4, 4)))
-
-extern CORE_ADDR sigtramp_saved_pc (struct frame_info *);
+#define FRAME_SAVED_PC(frame) m68k_linux_frame_saved_pc (frame)
+extern CORE_ADDR m68k_linux_frame_saved_pc (struct frame_info *);
 
-#define IN_SIGTRAMP(pc,name) in_sigtramp (pc)
-extern int in_sigtramp (CORE_ADDR pc);
+#define IN_SIGTRAMP(pc,name) m68k_linux_in_sigtramp (pc)
+extern int m68k_linux_in_sigtramp (CORE_ADDR pc);
diff --git a/gdb/m68klinux-nat.c b/gdb/m68klinux-nat.c
index ffb5532..10f4a19 100644
--- a/gdb/m68klinux-nat.c
+++ b/gdb/m68klinux-nat.c
@@ -594,40 +594,102 @@ kernel_u_size (void)
   return (sizeof (struct user));
 }
 
-/* Return non-zero if PC points into the signal trampoline.  */
+/* Check whether insn1 and insn2 are parts of a signal trampoline.  */
+
+#define IS_SIGTRAMP(insn1, insn2)					\
+  (/* addaw #20,sp; moveq #119,d0; trap #0 */				\
+   (insn1 == 0xdefc0014 && insn2 == 0x70774e40)				\
+   /* moveq #119,d0; trap #0 */						\
+   || insn1 == 0x70774e40)
+
+#define IS_RT_SIGTRAMP(insn1, insn2)					\
+  (/* movel #173,d0; trap #0 */						\
+   (insn1 == 0x203c0000 && insn2 == 0x00ad4e40)				\
+   /* moveq #82,d0; notb d0; trap #0 */					\
+   || (insn1 == 0x70524600 && (insn2 >> 16) == 0x4e40))
+
+/* Return non-zero if PC points into the signal trampoline.  For the sake
+   of m68k_linux_frame_saved_pc we also distinguish between non-RT and RT
+   signal trampolines.  */
 
 int
-in_sigtramp (CORE_ADDR pc)
+m68k_linux_in_sigtramp (CORE_ADDR pc)
 {
   CORE_ADDR sp;
-  char buf[TARGET_SHORT_BIT / TARGET_CHAR_BIT];
-  int insn;
+  char buf[12];
+  unsigned long insn0, insn1, insn2;
 
-  sp = read_register (SP_REGNUM);
-  if (pc - 2 < sp)
+  if (read_memory_nobpt (pc - 4, buf, sizeof (buf)))
     return 0;
+  insn1 = extract_unsigned_integer (buf + 4, 4);
+  insn2 = extract_unsigned_integer (buf + 8, 4);
+  if (IS_SIGTRAMP (insn1, insn2))
+    return 1;
+  if (IS_RT_SIGTRAMP (insn1, insn2))
+    return 2;
 
-  if (read_memory_nobpt (pc, buf, sizeof (buf)))
-    return 0;
-  insn = extract_unsigned_integer (buf, sizeof (buf));
-  if (insn == 0xdefc		/* addaw #,sp */
-      || insn == 0x7077		/* moveq #119,d0 */
-      || insn == 0x4e40		/* trap #0 */
-      || insn == 0x203c /* movel #,d0 */ )
+  insn0 = extract_unsigned_integer (buf, 4);
+  if (IS_SIGTRAMP (insn0, insn1))
     return 1;
+  if (IS_RT_SIGTRAMP (insn0, insn1))
+    return 2;
 
-  if (read_memory_nobpt (pc - 2, buf, sizeof (buf)))
-    return 0;
-  insn = extract_unsigned_integer (buf, sizeof (buf));
-  if (insn == 0xdefc		/* addaw #,sp */
-      || insn == 0x7077		/* moveq #119,d0 */
-      || insn == 0x4e40		/* trap #0 */
-      || insn == 0x203c /* movel #,d0 */ )
+  insn0 = (insn0 << 16) | (insn1 >> 16);
+  insn1 = (insn1 << 16) | (insn2 >> 16);
+  if (IS_SIGTRAMP (insn0, insn1))
     return 1;
+  if (IS_RT_SIGTRAMP (insn0, insn1))
+    return 2;
 
   return 0;
 }
 
+/* Offset to saved PC in sigcontext, from <asm/sigcontext.h>.  */
+#define SIGCONTEXT_PC_OFFSET 26
+
+/* Offset to saved PC in ucontext, from <asm/ucontext.h>.  */
+#define UCONTEXT_PC_OFFSET 88
+
+/* Get saved user PC for sigtramp from sigcontext or ucontext.  */
+
+static CORE_ADDR
+m68k_linux_sigtramp_saved_pc (struct frame_info *frame)
+{
+  CORE_ADDR sigcontext_addr;
+  char buf[TARGET_PTR_BIT / TARGET_CHAR_BIT];
+  int ptrbytes = TARGET_PTR_BIT / TARGET_CHAR_BIT;
+  int sigcontext_offs = (2 * TARGET_INT_BIT) / TARGET_CHAR_BIT;
+
+  /* Get sigcontext address, it is the third parameter on the stack.  */
+  if (frame->next)
+    sigcontext_addr = read_memory_integer (FRAME_ARGS_ADDRESS (frame->next)
+					   + FRAME_ARGS_SKIP
+					   + sigcontext_offs,
+					   ptrbytes);
+  else
+    sigcontext_addr = read_memory_integer (read_register (SP_REGNUM)
+					   + sigcontext_offs,
+					   ptrbytes);
+
+  /* Don't cause a memory_error when accessing sigcontext in case the
+     stack layout has changed or the stack is corrupt.  */
+  if (m68k_linux_in_sigtramp (frame->pc) == 2)
+    target_read_memory (sigcontext_addr + UCONTEXT_PC_OFFSET, buf, ptrbytes);
+  else
+    target_read_memory (sigcontext_addr + SIGCONTEXT_PC_OFFSET, buf, ptrbytes);
+  return extract_unsigned_integer (buf, ptrbytes);
+}
+
+/* Return the saved program counter for FRAME.  */
+
+CORE_ADDR
+m68k_linux_frame_saved_pc (struct frame_info *frame)
+{
+  if (frame->signal_handler_caller)
+    return m68k_linux_sigtramp_saved_pc (frame);
+
+  return read_memory_integer (frame->frame + 4, 4);
+}
 
 /* Register that we are able to handle GNU/Linux ELF core file
    formats.  */