* sparc-linux-tdep.c (sparc32_linux_sigtramp_p): Fix

	signal return stub symbol names, __restore and __restore_rt are
	the i386 symbol names not the sparc ones.
	(sparc32_linux_sigtramp_frame_cache): Document bits/sigcontext.h
	as where the offsets were obtained from.
	* sparc64-linux-tdep.c (LINUX64_RT_SIGTRAMP_INSN0,
	LINUX64_RT_SIGTRAMP_INSN1): New defines.
	(sparc64_linux_sigtramp_start, sparc64_linux_sigtramp_p,
	sparc64_linux_sigtramp_frame_cache,
	sparc64_linux_sigtramp_frame_this_id,
	sparc64_linux_sigtramp_frame_prev_register,
	sparc64_linux_sigtramp_frame_sniffer): New functions.
	(sparc64_linux_sigtramp_frame_unwind): New frame unwinder.
	(sparc64_linux_init_abi): Register sigtramp frame sniffer.
	* Makefile.in (sparc64-linux-tdep.o): Update dependencies.

1 files changed, 177 insertions, 0 deletions

diff --git a/gdb/sparc64-linux-tdep.c b/gdb/sparc64-linux-tdep.c
index 45c01939779..0047625b1c9 100644
--- a/gdb/sparc64-linux-tdep.c
+++ b/gdb/sparc64-linux-tdep.c
@@ -20,17 +20,194 @@
    Boston, MA 02111-1307, USA.  */
 
 #include "defs.h"
+#include "frame.h"
+#include "frame-unwind.h"
 #include "gdbarch.h"
 #include "osabi.h"
 #include "solib-svr4.h"
+#include "symtab.h"
+#include "trad-frame.h"
+
+#include "gdb_assert.h"
+#include "gdb_string.h"
 
 #include "sparc64-tdep.h"
 
+/* The instruction sequence for RT signals is
+       mov __NR_rt_sigreturn, %g1	! hex: 0x82102065
+       ta  0x6d				! hex: 0x91d0206d
+
+   The effect is to call the system call rt_sigreturn.
+   Note that 64-bit binaries only use this RT signal return method.  */
+
+#define LINUX64_RT_SIGTRAMP_INSN0	0x82102065
+#define LINUX64_RT_SIGTRAMP_INSN1	0x91d0206d
+
+/* If PC is in a sigtramp routine consisting of the instructions
+   LINUX64_RT_SIGTRAMP_INSN0 and LINUX64_RT_SIGTRAMP_INSN1, return
+   the address of the start of the routine.  Otherwise, return 0.  */
+
+static CORE_ADDR
+sparc64_linux_sigtramp_start (struct frame_info *next_frame)
+{
+  CORE_ADDR pc = frame_pc_unwind (next_frame);
+  ULONGEST word0, word1;
+  unsigned char buf[8];		/* Two instructions.  */
+
+  /* We only recognize a signal trampoline if PC is at the start of
+     one of the instructions.  We optimize for finding the PC at the
+     start of the instruction sequence, 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 (!safe_frame_unwind_memory (next_frame, pc, buf, sizeof buf))
+    return 0;
+
+  word0 = extract_unsigned_integer (buf, 4);
+  if (word0 != LINUX64_RT_SIGTRAMP_INSN0)
+    {
+      if (word0 != LINUX64_RT_SIGTRAMP_INSN1)
+	return 0;
+
+      pc -= 4;
+      if (!safe_frame_unwind_memory (next_frame, pc, buf, sizeof buf))
+	return 0;
+
+      word0 = extract_unsigned_integer (buf, 4);
+    }
+
+  word1 = extract_unsigned_integer (buf + 4, 4);
+  if (word0 != LINUX64_RT_SIGTRAMP_INSN0
+      || word1 != LINUX64_RT_SIGTRAMP_INSN1)
+    return 0;
+
+  return pc;
+}
+
+static int
+sparc64_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 is
+     named __rt_sigreturn_stub.  However, is 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 (sparc64_linux_sigtramp_start (next_frame) != 0);
+
+  return (strcmp ("__rt_sigreturn_stub", name) == 0);
+}
+
+static struct sparc_frame_cache *
+sparc64_linux_sigtramp_frame_cache (struct frame_info *next_frame,
+				    void **this_cache)
+{
+  struct sparc_frame_cache *cache;
+  CORE_ADDR sigcontext_addr, addr;
+  int regnum;
+
+  if (*this_cache)
+    return *this_cache;
+
+  cache = sparc_frame_cache (next_frame, this_cache);
+  gdb_assert (cache == *this_cache);
+
+  regnum = SPARC_SP_REGNUM;
+  cache->base = frame_unwind_register_unsigned (next_frame, regnum);
+  if (cache->base & 1)
+    cache->base += BIAS;
+
+  regnum = SPARC_O1_REGNUM;
+  sigcontext_addr = frame_unwind_register_unsigned (next_frame, regnum);
+
+  /* If this is a RT signal trampoline, adjust SIGCONTEXT_ADDR
+     accordingly.  */
+  addr = sparc64_linux_sigtramp_start (next_frame);
+  if (addr)
+    sigcontext_addr += 128;
+  else
+    addr = frame_func_unwind (next_frame);
+
+  cache->pc = addr;
+
+  cache->saved_regs = trad_frame_alloc_saved_regs (next_frame);
+
+  /* Offsets from <bits/sigcontext.h> */
+
+  /* Since %g0 is always zero, keep the identity encoding.  */
+  for (addr = sigcontext_addr + 8, regnum = SPARC_G1_REGNUM;
+       regnum <= SPARC_O7_REGNUM; regnum++, addr += 8)
+    cache->saved_regs[regnum].addr = addr;
+
+  cache->saved_regs[SPARC64_STATE_REGNUM].addr = addr + 0;
+  cache->saved_regs[SPARC64_PC_REGNUM].addr = addr + 8;
+  cache->saved_regs[SPARC64_NPC_REGNUM].addr = addr + 16;
+  cache->saved_regs[SPARC64_Y_REGNUM].addr = addr + 24;
+  cache->saved_regs[SPARC64_FPRS_REGNUM].addr = addr + 28;
+
+  for (regnum = SPARC_L0_REGNUM, addr = cache->base;
+       regnum <= SPARC_I7_REGNUM; regnum++, addr += 8)
+    cache->saved_regs[regnum].addr = addr;
+
+  return cache;
+}
+
+static void
+sparc64_linux_sigtramp_frame_this_id (struct frame_info *next_frame,
+				      void **this_cache,
+				      struct frame_id *this_id)
+{
+  struct sparc_frame_cache *cache =
+    sparc64_linux_sigtramp_frame_cache (next_frame, this_cache);
+
+  (*this_id) = frame_id_build (cache->base, cache->pc);
+}
+
+static void
+sparc64_linux_sigtramp_frame_prev_register (struct frame_info *next_frame,
+					    void **this_cache,
+					    int regnum, int *optimizedp,
+					    enum lval_type *lvalp,
+					    CORE_ADDR *addrp,
+					    int *realnump, void *valuep)
+{
+  struct sparc_frame_cache *cache =
+    sparc64_linux_sigtramp_frame_cache (next_frame, this_cache);
+
+  trad_frame_get_prev_register (next_frame, cache->saved_regs, regnum,
+				optimizedp, lvalp, addrp, realnump, valuep);
+}
+
+static const struct frame_unwind sparc64_linux_sigtramp_frame_unwind =
+{
+  SIGTRAMP_FRAME,
+  sparc64_linux_sigtramp_frame_this_id,
+  sparc64_linux_sigtramp_frame_prev_register
+};
+
+static const struct frame_unwind *
+sparc64_linux_sigtramp_frame_sniffer (struct frame_info *next_frame)
+{
+  if (sparc64_linux_sigtramp_p (next_frame))
+    return &sparc64_linux_sigtramp_frame_unwind;
+
+  return NULL;
+}
+
 static void
 sparc64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 
+  frame_unwind_append_sniffer (gdbarch, sparc64_linux_sigtramp_frame_sniffer);
+
   /* GNU/Linux is very similar to Solaris ...  */
   sparc64_sol2_init_abi (info, gdbarch);