2004-09-30 Kei Sakamoto <sakamoto.kei@renesas.com>

        Add m32r-linux support.
        * configure.tgt: Add m32r*-*-linux*.
        * Makefile.in (ALLDEPFILES): Add m32r-tdep.c, m32r-linux-nat.c
        and m32r-linux-tdep.c.
        (m32r-linux-nat.o, m32r-linux-tdep.o): New dependencies.
        * m32r-tdep.c: Move some definitions to m32r-tdep.h.
        * config/djgpp/fnchange.lst: Add m32r-linux-nat.c and
        m32r-linux-tdep.c.
        * m32r-tdep.h, m32r-linux-nat.c, m32r-linux-tdep.c,
        config/m32r/linux.mh, config/m32r/linux.mt,
        config/m32r/nm-linux.h: New files.

1 files changed, 336 insertions, 0 deletions

diff --git a/gdb/m32r-linux-tdep.c b/gdb/m32r-linux-tdep.c
new file mode 100644
index 0000000..d2ca1a9
--- /dev/null
+++ b/gdb/m32r-linux-tdep.c
@@ -0,0 +1,336 @@
+/* Target-dependent code for GNU/Linux m32r.
+
+   Copyright 2004 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include "defs.h"
+#include "gdbcore.h"
+#include "frame.h"
+#include "value.h"
+#include "regcache.h"
+#include "inferior.h"
+#include "osabi.h"
+#include "reggroups.h"
+
+#include "gdb_string.h"
+
+#include "glibc-tdep.h"
+#include "solib-svr4.h"
+
+#include "trad-frame.h"
+#include "frame-unwind.h"
+
+#include "m32r-tdep.h"
+
+
+/* Recognizing signal handler frames.  */
+
+/* GNU/Linux has two flavors of signals.  Normal signal handlers, and
+   "realtime" (RT) signals.  The RT signals can provide additional
+   information to the signal handler if the SA_SIGINFO flag is set
+   when establishing a signal handler using `sigaction'.  It is not
+   unlikely that future versions of GNU/Linux will support SA_SIGINFO
+   for normal signals too.  */
+
+/* When the m32r Linux kernel calls a signal handler and the
+   SA_RESTORER flag isn't set, the return address points to a bit of
+   code on the stack.  This function returns whether the PC appears to
+   be within this bit of code.
+
+   The instruction sequence for normal signals is
+       ldi    r7, #__NR_sigreturn
+       trap   #2
+   or 0x67 0x77 0x10 0xf2.
+
+   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 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.  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
+   what the GNU C Library has been doing for quite some time now.
+   However, as of version 2.1.2, the GNU C Library uses signal
+   trampolines (named __restore and __restore_rt) that are identical
+   to the ones used by the kernel.  Therefore, these trampolines are
+   supported too.  */
+
+static const unsigned char linux_sigtramp_code[] = {
+  0x67, 0x77, 0x10, 0xf2,
+};
+
+/* If PC is in a sigtramp routine, return the address of the start of
+   the routine.  Otherwise, return 0.  */
+
+static CORE_ADDR
+m32r_linux_sigtramp_start (CORE_ADDR pc, struct frame_info *next_frame)
+{
+  unsigned char buf[4];
+
+  /* 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 (pc % 2 != 0)
+    {
+      if (!safe_frame_unwind_memory (next_frame, pc, buf, 2))
+	return 0;
+
+      if (memcmp (buf, linux_sigtramp_code, 2) == 0)
+	pc -= 2;
+      else
+	return 0;
+    }
+
+  if (!safe_frame_unwind_memory (next_frame, pc, buf, 4))
+    return 0;
+
+  if (memcmp (buf, linux_sigtramp_code, 4) != 0)
+    return 0;
+
+  return pc;
+}
+
+/* This function does the same for RT signals.  Here the instruction
+   sequence is
+       ldi    r7, #__NR_rt_sigreturn
+       trap   #2
+   or 0x97 0xf0 0x00 0xad 0x10 0xf2 0xf0 0x00.
+
+   The effect is to call the system call rt_sigreturn.  */
+
+static const unsigned char linux_rt_sigtramp_code[] = {
+  0x97, 0xf0, 0x00, 0xad, 0x10, 0xf2, 0xf0, 0x00,
+};
+
+/* If PC is in a RT sigtramp routine, return the address of the start
+   of the routine.  Otherwise, return 0.  */
+
+static CORE_ADDR
+m32r_linux_rt_sigtramp_start (CORE_ADDR pc, struct frame_info *next_frame)
+{
+  unsigned char buf[4];
+
+  /* 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 (pc % 2 != 0)
+    return 0;
+
+  if (!safe_frame_unwind_memory (next_frame, pc, buf, 4))
+    return 0;
+
+  if (memcmp (buf, linux_rt_sigtramp_code, 4) == 0)
+    {
+      if (!safe_frame_unwind_memory (next_frame, pc + 4, buf, 4))
+	return 0;
+
+      if (memcmp (buf, linux_rt_sigtramp_code + 4, 4) == 0)
+	return pc;
+    }
+  else if (memcmp (buf, linux_rt_sigtramp_code + 4, 4) == 0)
+    {
+      if (!safe_frame_unwind_memory (next_frame, pc - 4, buf, 4))
+	return 0;
+
+      if (memcmp (buf, linux_rt_sigtramp_code, 4) == 0)
+	return pc - 4;
+    }
+
+  return 0;
+}
+
+static int
+m32r_linux_pc_in_sigtramp (CORE_ADDR pc, char *name,
+			   struct frame_info *next_frame)
+{
+  /* 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 (m32r_linux_sigtramp_start (pc, next_frame) != 0
+	    || m32r_linux_rt_sigtramp_start (pc, next_frame) != 0);
+
+  return (strcmp ("__restore", name) == 0
+	  || strcmp ("__restore_rt", name) == 0);
+}
+
+/* From <asm/sigcontext.h>.  */
+static int m32r_linux_sc_reg_offset[] = {
+  4 * 4,			/* r0 */
+  5 * 4,			/* r1 */
+  6 * 4,			/* r2 */
+  7 * 4,			/* r3 */
+  0 * 4,			/* r4 */
+  1 * 4,			/* r5 */
+  2 * 4,			/* r6 */
+  8 * 4,			/* r7 */
+  9 * 4,			/* r8 */
+  10 * 4,			/* r9 */
+  11 * 4,			/* r10 */
+  12 * 4,			/* r11 */
+  13 * 4,			/* r12 */
+  21 * 4,			/* fp */
+  22 * 4,			/* lr */
+  -1 * 4,			/* sp */
+  16 * 4,			/* psw */
+  -1 * 4,			/* cbr */
+  23 * 4,			/* spi */
+  20 * 4,			/* spu */
+  19 * 4,			/* bpc */
+  17 * 4,			/* pc */
+  15 * 4,			/* accl */
+  14 * 4			/* acch */
+};
+
+struct m32r_frame_cache
+{
+  CORE_ADDR base, pc;
+  struct trad_frame_saved_reg *saved_regs;
+};
+
+static struct m32r_frame_cache *
+m32r_linux_sigtramp_frame_cache (struct frame_info *next_frame,
+				 void **this_cache)
+{
+  struct m32r_frame_cache *cache;
+  CORE_ADDR sigcontext_addr, addr;
+  int regnum;
+
+  if ((*this_cache) != NULL)
+    return (*this_cache);
+  cache = FRAME_OBSTACK_ZALLOC (struct m32r_frame_cache);
+  (*this_cache) = cache;
+  cache->saved_regs = trad_frame_alloc_saved_regs (next_frame);
+
+  cache->base = frame_unwind_register_unsigned (next_frame, M32R_SP_REGNUM);
+  sigcontext_addr = cache->base + 4;
+
+  cache->pc = frame_pc_unwind (next_frame);
+  addr = m32r_linux_sigtramp_start (cache->pc, next_frame);
+  if (addr == 0)
+    {
+      /* If this is a RT signal trampoline, adjust SIGCONTEXT_ADDR
+         accordingly.  */
+      addr = m32r_linux_rt_sigtramp_start (cache->pc, 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);
+
+  for (regnum = 0; regnum < sizeof (m32r_linux_sc_reg_offset) / 4; regnum++)
+    {
+      if (m32r_linux_sc_reg_offset[regnum] >= 0)
+	cache->saved_regs[regnum].addr =
+	  sigcontext_addr + m32r_linux_sc_reg_offset[regnum];
+    }
+
+  return cache;
+}
+
+static void
+m32r_linux_sigtramp_frame_this_id (struct frame_info *next_frame,
+				   void **this_cache,
+				   struct frame_id *this_id)
+{
+  struct m32r_frame_cache *cache =
+    m32r_linux_sigtramp_frame_cache (next_frame, this_cache);
+
+  (*this_id) = frame_id_build (cache->base, cache->pc);
+}
+
+static void
+m32r_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 m32r_frame_cache *cache =
+    m32r_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 m32r_linux_sigtramp_frame_unwind = {
+  SIGTRAMP_FRAME,
+  m32r_linux_sigtramp_frame_this_id,
+  m32r_linux_sigtramp_frame_prev_register
+};
+
+static const struct frame_unwind *
+m32r_linux_sigtramp_frame_sniffer (struct frame_info *next_frame)
+{
+  CORE_ADDR pc = frame_pc_unwind (next_frame);
+  char *name;
+
+  find_pc_partial_function (pc, &name, NULL, NULL);
+  if (m32r_linux_pc_in_sigtramp (pc, name, next_frame))
+    return &m32r_linux_sigtramp_frame_unwind;
+
+  return NULL;
+}
+
+static void
+m32r_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
+{
+  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+
+  /* Since EVB register is not available for native debug, we reduce
+     the number of registers.  */
+  set_gdbarch_num_regs (gdbarch, M32R_NUM_REGS - 1);
+
+  frame_unwind_append_sniffer (gdbarch, m32r_linux_sigtramp_frame_sniffer);
+
+  /* GNU/Linux uses SVR4-style shared libraries.  */
+  set_solib_svr4_fetch_link_map_offsets
+    (gdbarch, svr4_ilp32_fetch_link_map_offsets);
+}
+
+/* Provide a prototype to silence -Wmissing-prototypes.  */
+extern void _initialize_m32r_linux_tdep (void);
+
+void
+_initialize_m32r_linux_tdep (void)
+{
+  gdbarch_register_osabi (bfd_arch_m32r, 0, GDB_OSABI_LINUX,
+			  m32r_linux_init_abi);
+}