2004-04-24 Randolph Chung <tausq@debian.org>

	* configure.host (hppa*-*-linux*): New target.
	* configure.tgt (hppa*-*-linux*): Likewise.
	* hppa-tdep.c (hppa_gdbarch_init): Set cannot_fetch_register, move
	gdbarch_init_osabi() call earlier so that osabi-specific frame
	unwinders can be registered first.
	* config/djgpp/fnchange.lst: Add entries for hppa-linux-tdep.c and
	hppa-linux-nat.c.
	* config/pa/tm-hppa.h (ISR_REGNUM, PID0_REGNUM, PID1_REGNUM)
	(PID2_REGNUM, PID3_REGNUM): Add definitions of some register numbers.
	* config/pa/linux.mh: New file.
	* config/pa/linux.mt: New file.
	* config/pa/nm-linux.h: New file.
	* config/pa/xm-linux.h: New file.
	* hppa-linux-nat.c: New file.
	* hppa-linux-tdep.c: New file.

1 files changed, 499 insertions, 0 deletions

diff --git a/gdb/hppa-linux-tdep.c b/gdb/hppa-linux-tdep.c
new file mode 100644
index 0000000..bdcb4a7
--- /dev/null
+++ b/gdb/hppa-linux-tdep.c
@@ -0,0 +1,499 @@
+/* Target-dependent code for Linux running on PA-RISC, for GDB.
+
+   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 "osabi.h"
+#include "target.h"
+#include "objfiles.h"
+#include "solib-svr4.h"
+#include "glibc-tdep.h"
+#include "frame-unwind.h"
+#include "trad-frame.h"
+#include "dwarf2-frame.h"
+#include "hppa-tdep.h"
+
+#if 0
+/* Convert DWARF register number REG to the appropriate register
+   number used by GDB.  */
+static int
+hppa_dwarf_reg_to_regnum (int reg)
+{
+  /* registers 0 - 31 are the same in both sets */
+  if (reg < 32)
+    return reg;
+
+  /* dwarf regs 32 to 85 are fpregs 4 - 31 */
+  if (reg >= 32 && reg <= 85)
+    return FP4_REGNUM + (reg - 32);
+
+  warning ("Unmapped DWARF Register #%d encountered\n", reg);
+  return -1;
+}
+#endif
+
+static void
+hppa_linux_target_write_pc (CORE_ADDR v, ptid_t ptid)
+{
+  /* Probably this should be done by the kernel, but it isn't.  */
+  write_register_pid (PCOQ_HEAD_REGNUM, v | 0x3, ptid);
+  write_register_pid (PCOQ_TAIL_REGNUM, (v + 4) | 0x3, ptid);
+}
+
+/* An instruction to match.  */
+struct insn_pattern
+{
+  unsigned int data;            /* See if it matches this....  */
+  unsigned int mask;            /* ... with this mask.  */
+};
+
+/* See bfd/elf32-hppa.c */
+static struct insn_pattern hppa_long_branch_stub[] = {
+  /* ldil LR'xxx,%r1 */
+  { 0x20200000, 0xffe00000 },
+  /* be,n RR'xxx(%sr4,%r1) */
+  { 0xe0202002, 0xffe02002 }, 
+  { 0, 0 }
+};
+
+static struct insn_pattern hppa_long_branch_pic_stub[] = {
+  /* b,l .+8, %r1 */
+  { 0xe8200000, 0xffe00000 },
+  /* addil LR'xxx - ($PIC_pcrel$0 - 4), %r1 */
+  { 0x28200000, 0xffe00000 },
+  /* be,n RR'xxxx - ($PIC_pcrel$0 - 8)(%sr4, %r1) */
+  { 0xe0202002, 0xffe02002 }, 
+  { 0, 0 }
+};
+
+static struct insn_pattern hppa_import_stub[] = {
+  /* addil LR'xxx, %dp */
+  { 0x2b600000, 0xffe00000 },
+  /* ldw RR'xxx(%r1), %r21 */
+  { 0x48350000, 0xffffb000 },
+  /* bv %r0(%r21) */
+  { 0xeaa0c000, 0xffffffff },
+  /* ldw RR'xxx+4(%r1), %r19 */
+  { 0x48330000, 0xffffb000 },
+  { 0, 0 }
+};
+
+static struct insn_pattern hppa_import_pic_stub[] = {
+  /* addil LR'xxx,%r19 */
+  { 0x2a600000, 0xffe00000 },
+  /* ldw RR'xxx(%r1),%r21 */
+  { 0x48350000, 0xffffb000 },
+  /* bv %r0(%r21) */
+  { 0xeaa0c000, 0xffffffff },
+  /* ldw RR'xxx+4(%r1),%r19 */
+  { 0x48330000, 0xffffb000 },
+  { 0, 0 },
+};
+
+static struct insn_pattern hppa_plt_stub[] = {
+  /* b,l 1b, %r20 - 1b is 3 insns before here */
+  { 0xea9f1fdd, 0xffffffff },
+  /* depi 0,31,2,%r20 */
+  { 0xd6801c1e, 0xffffffff },
+  { 0, 0 }
+};
+
+static struct insn_pattern hppa_sigtramp[] = {
+  /* ldi 0, %r25 or ldi 1, %r25 */
+  { 0x34190000, 0xfffffffd },
+  /* ldi __NR_rt_sigreturn, %r20 */
+  { 0x3414015a, 0xffffffff },
+  /* be,l 0x100(%sr2, %r0), %sr0, %r31 */
+  { 0xe4008200, 0xffffffff },
+  /* nop */
+  { 0x08000240, 0xffffffff },
+  { 0, 0 }
+};
+
+#define HPPA_MAX_INSN_PATTERN_LEN (4)
+
+/* Return non-zero if the instructions at PC match the series
+   described in PATTERN, or zero otherwise.  PATTERN is an array of
+   'struct insn_pattern' objects, terminated by an entry whose mask is
+   zero.
+
+   When the match is successful, fill INSN[i] with what PATTERN[i]
+   matched.  */
+static int
+insns_match_pattern (CORE_ADDR pc,
+                     struct insn_pattern *pattern,
+                     unsigned int *insn)
+{
+  int i;
+  CORE_ADDR npc = pc;
+
+  for (i = 0; pattern[i].mask; i++)
+    {
+      insn[i] = read_memory_unsigned_integer (npc, 4);
+      if ((insn[i] & pattern[i].mask) == pattern[i].data)
+        npc += 4;
+      else
+        return 0;
+    }
+  return 1;
+}
+
+static int
+hppa_linux_in_dyncall (CORE_ADDR pc)
+{
+  static CORE_ADDR dyncall = 0;
+
+  /* FIXME: if we switch exec files, dyncall should be reinitialized */
+  if (!dyncall)
+    {
+      struct minimal_symbol *minsym;
+
+      minsym = lookup_minimal_symbol ("$$dyncall", NULL, NULL);
+      if (minsym)
+	dyncall = SYMBOL_VALUE_ADDRESS (minsym);
+      else
+	dyncall = -1;
+    }
+
+  return pc == dyncall;
+}
+
+/* There are several kinds of "trampolines" that we need to deal with:
+   - long branch stubs: these are inserted by the linker when a branch
+     target is too far away for a branch insn to reach
+   - plt stubs: these should go into the .plt section, so are easy to find
+   - import stubs: used to call from object to shared lib or shared lib to 
+     shared lib; these go in regular text sections.  In fact the linker tries
+     to put them throughout the code because branches have limited reachability.
+     We use the same mechanism as ppc64 to recognize the stub insn patterns.
+   - $$dyncall: similar to hpux, hppa-linux uses $$dyncall for indirect function
+     calls. $$dyncall is exported by libgcc.a  */
+static int
+hppa_linux_in_solib_call_trampoline (CORE_ADDR pc, char *name)
+{
+  unsigned int insn[HPPA_MAX_INSN_PATTERN_LEN];
+  int r;
+
+  r = in_plt_section (pc, name)
+      || hppa_linux_in_dyncall (pc)
+      || insns_match_pattern (pc, hppa_import_stub, insn)
+      || insns_match_pattern (pc, hppa_import_pic_stub, insn)
+      || insns_match_pattern (pc, hppa_long_branch_stub, insn)
+      || insns_match_pattern (pc, hppa_long_branch_pic_stub, insn);
+
+  return r;
+}
+
+static CORE_ADDR
+hppa_linux_skip_trampoline_code (CORE_ADDR pc)
+{
+  unsigned int insn[HPPA_MAX_INSN_PATTERN_LEN];
+  int dp_rel, pic_rel;
+
+  /* dyncall handles both PLABELs and direct addresses */
+  if (hppa_linux_in_dyncall (pc))
+    {
+      pc = (CORE_ADDR) read_register (22);
+
+      /* PLABELs have bit 30 set; if it's a PLABEL, then dereference it */
+      if (pc & 0x2)
+	pc = (CORE_ADDR) read_memory_integer (pc & ~0x3, TARGET_PTR_BIT / 8);
+
+      return pc;
+    }
+
+  dp_rel = pic_rel = 0;
+  if ((dp_rel = insns_match_pattern (pc, hppa_import_stub, insn))
+      || (pic_rel = insns_match_pattern (pc, hppa_import_pic_stub, insn)))
+    {
+      /* Extract the target address from the addil/ldw sequence.  */
+      pc = hppa_extract_21 (insn[0]) + hppa_extract_14 (insn[1]);
+
+      if (dp_rel)
+        pc += (CORE_ADDR) read_register (27);
+      else
+        pc += (CORE_ADDR) read_register (19);
+
+      /* fallthrough */
+    }
+
+  if (in_plt_section (pc, NULL))
+    {
+      pc = (CORE_ADDR) read_memory_integer (pc, TARGET_PTR_BIT / 8);
+
+      /* if the plt slot has not yet been resolved, the target will
+         be the plt stub */
+      if (in_plt_section (pc, NULL))
+	{
+	  /* Sanity check: are we pointing to the plt stub? */
+  	  if (insns_match_pattern (pc, hppa_plt_stub, insn))
+	    {
+	      /* this should point to the fixup routine */
+      	      pc = (CORE_ADDR) read_memory_integer (pc + 8, TARGET_PTR_BIT / 8);
+	    }
+	  else
+	    {
+	      error ("Cannot resolve plt stub at 0x%s\n",
+		     paddr_nz (pc));
+	      pc = 0;
+	    }
+	}
+    }
+
+  return pc;
+}
+
+/* Signal frames.  */
+
+/* (This is derived from MD_FALLBACK_FRAME_STATE_FOR in gcc.)
+ 
+   Unfortunately, because of various bugs and changes to the kernel,
+   we have several cases to deal with.
+
+   In 2.4, the signal trampoline is 4 bytes, and pc should point directly at 
+   the beginning of the trampoline and struct rt_sigframe.
+
+   In <= 2.6.5-rc2-pa3, the signal trampoline is 9 bytes, and pc points at
+   the 4th word in the trampoline structure.  This is wrong, it should point 
+   at the 5th word.  This is fixed in 2.6.5-rc2-pa4.
+
+   To detect these cases, we first take pc, align it to 64-bytes
+   to get the beginning of the signal frame, and then check offsets 0, 4
+   and 5 to see if we found the beginning of the trampoline.  This will
+   tell us how to locate the sigcontext structure.
+
+   Note that with a 2.4 64-bit kernel, the signal context is not properly
+   passed back to userspace so the unwind will not work correctly.  */
+static CORE_ADDR
+hppa_linux_sigtramp_find_sigcontext (CORE_ADDR sp)
+{
+  unsigned int dummy[HPPA_MAX_INSN_PATTERN_LEN];
+  int offs = 0;
+  int try;
+  /* offsets to try to find the trampoline */
+  static int pcoffs[] = { 0, 4*4, 5*4 };
+  /* offsets to the rt_sigframe structure */
+  static int sfoffs[] = { 4*4, 10*4, 10*4 };
+
+  /* rt_sigreturn trampoline:
+     3419000x ldi 0, %r25 or ldi 1, %r25   (x = 0 or 2)
+     3414015a ldi __NR_rt_sigreturn, %r20 
+     e4008200 be,l 0x100(%sr2, %r0), %sr0, %r31
+     08000240 nop  */
+
+  for (try = 0; try < ARRAY_SIZE (pcoffs); try++)
+    {
+      if (insns_match_pattern (sp + pcoffs[try], hppa_sigtramp, dummy))
+	{
+          offs = sfoffs[try];
+	  break;
+	}
+    }
+
+  if (offs == 0)
+    return 0;
+
+  /* sp + sfoffs[try] points to a struct rt_sigframe, which contains
+     a struct siginfo and a struct ucontext.  struct ucontext contains
+     a struct sigcontext. Return an offset to this sigcontext here.  Too 
+     bad we cannot include system specific headers :-(.  
+     sizeof(struct siginfo) == 128
+     offsetof(struct ucontext, uc_mcontext) == 24.  */
+  return sp + sfoffs[try] + 128 + 24;
+}
+
+struct hppa_linux_sigtramp_unwind_cache
+{
+  CORE_ADDR base;
+  struct trad_frame_saved_reg *saved_regs;
+};
+
+static struct hppa_linux_sigtramp_unwind_cache *
+hppa_linux_sigtramp_frame_unwind_cache (struct frame_info *next_frame,
+					void **this_cache)
+{
+  struct gdbarch *gdbarch = get_frame_arch (next_frame);
+  struct hppa_linux_sigtramp_unwind_cache *info;
+  CORE_ADDR sp, pc, scptr;
+  int i;
+
+  if (*this_cache)
+    return *this_cache;
+
+  info = FRAME_OBSTACK_ZALLOC (struct hppa_linux_sigtramp_unwind_cache);
+  *this_cache = info;
+  info->saved_regs = trad_frame_alloc_saved_regs (next_frame);
+
+  pc = frame_pc_unwind (next_frame);
+  sp = (pc & ~63);
+  scptr = hppa_linux_sigtramp_find_sigcontext (sp);
+
+  /* structure of struct sigcontext:
+   
+     struct sigcontext {
+	unsigned long sc_flags;
+	unsigned long sc_gr[32]; 
+	unsigned long long sc_fr[32];
+	unsigned long sc_iasq[2];
+	unsigned long sc_iaoq[2];
+	unsigned long sc_sar;           */
+
+  /* Skip sc_flags.  */
+  scptr += 4;
+
+  /* GR[0] is the psw, we don't restore that.  */
+  scptr += 4;
+
+  /* General registers.  */
+  for (i = 1; i < 32; i++)
+    {
+      info->saved_regs[R0_REGNUM + i].addr = scptr;
+      scptr += 4;
+    }
+
+  /* Pad.  */
+  scptr += 4;
+
+  /* FP regs; FP0-3 are not restored.  */
+  scptr += (8 * 4);
+
+  for (i = 4; i < 32; i++)
+    {
+      info->saved_regs[HPPA_FP0_REGNUM + (i * 2)].addr = scptr;
+      scptr += 4;
+      info->saved_regs[HPPA_FP0_REGNUM + (i * 2) + 1].addr = scptr;
+      scptr += 4;
+    }
+
+  /* IASQ/IAOQ. */
+  info->saved_regs[PCSQ_HEAD_REGNUM].addr = scptr;
+  scptr += 4;
+  info->saved_regs[PCSQ_TAIL_REGNUM].addr = scptr;
+  scptr += 4;
+
+  info->saved_regs[PCOQ_HEAD_REGNUM].addr = scptr;
+  scptr += 4;
+  info->saved_regs[PCOQ_TAIL_REGNUM].addr = scptr;
+  scptr += 4;
+
+  info->base = read_memory_unsigned_integer (
+		  info->saved_regs[HPPA_SP_REGNUM].addr, 4);
+
+  return info;
+}
+
+static void
+hppa_linux_sigtramp_frame_this_id (struct frame_info *next_frame,
+				   void **this_prologue_cache,
+				   struct frame_id *this_id)
+{
+  struct hppa_linux_sigtramp_unwind_cache *info
+    = hppa_linux_sigtramp_frame_unwind_cache (next_frame, this_prologue_cache);
+  *this_id = frame_id_build (info->base, frame_pc_unwind (next_frame));
+}
+
+static void
+hppa_linux_sigtramp_frame_prev_register (struct frame_info *next_frame,
+					 void **this_prologue_cache,
+					 int regnum, int *optimizedp,
+					 enum lval_type *lvalp, 
+					 CORE_ADDR *addrp,
+					 int *realnump, void *bufferp)
+{
+  struct hppa_linux_sigtramp_unwind_cache *info
+    = hppa_linux_sigtramp_frame_unwind_cache (next_frame, this_prologue_cache);
+  int pcoqt = (regnum == PCOQ_TAIL_REGNUM);
+
+  if (pcoqt)
+    regnum = PCOQ_HEAD_REGNUM;
+
+  trad_frame_prev_register (next_frame, info->saved_regs, regnum,
+                            optimizedp, lvalp, addrp, realnump, bufferp);
+
+  if (pcoqt)
+    store_unsigned_integer (bufferp, 4, 
+		      	    extract_unsigned_integer (bufferp, 4) + 4);
+}
+
+static const struct frame_unwind hppa_linux_sigtramp_frame_unwind = {
+  SIGTRAMP_FRAME,
+  hppa_linux_sigtramp_frame_this_id,
+  hppa_linux_sigtramp_frame_prev_register
+};
+
+/* hppa-linux always uses "new-style" rt-signals.  The signal handler's return
+   address should point to a signal trampoline on the stack.  The signal
+   trampoline is embedded in a rt_sigframe structure that is aligned on
+   the stack.  We take advantage of the fact that sp must be 64-byte aligned,
+   and the trampoline is small, so by rounding down the trampoline address
+   we can find the beginning of the struct rt_sigframe.  */
+static const struct frame_unwind *
+hppa_linux_sigtramp_unwind_sniffer (struct frame_info *next_frame)
+{
+  CORE_ADDR pc = frame_pc_unwind (next_frame);
+  CORE_ADDR sp = (pc & ~63);
+
+  if (hppa_linux_sigtramp_find_sigcontext (sp))
+    return &hppa_linux_sigtramp_frame_unwind;
+
+  return NULL;
+}
+
+/* Forward declarations.  */
+extern initialize_file_ftype _initialize_hppa_linux_tdep;
+
+static void
+hppa_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
+{
+  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+
+  /* Linux is always ELF.  */
+  tdep->is_elf = 1;
+
+  set_gdbarch_write_pc (gdbarch, hppa_linux_target_write_pc);
+
+  frame_unwind_append_sniffer (gdbarch, hppa_linux_sigtramp_unwind_sniffer);
+
+  /* GNU/Linux uses SVR4-style shared libraries.  */
+  set_solib_svr4_fetch_link_map_offsets
+    (gdbarch, svr4_ilp32_fetch_link_map_offsets);
+
+  set_gdbarch_in_solib_call_trampoline
+        (gdbarch, hppa_linux_in_solib_call_trampoline);
+  set_gdbarch_skip_trampoline_code
+	(gdbarch, hppa_linux_skip_trampoline_code);
+
+  /* GNU/Linux uses the dynamic linker included in the GNU C Library.  */
+  set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver);
+
+#if 0
+  /* Dwarf-2 unwinding support.  Not yet working.  */
+  set_gdbarch_dwarf_reg_to_regnum (gdbarch, hppa_dwarf_reg_to_regnum);
+  set_gdbarch_dwarf2_reg_to_regnum (gdbarch, hppa_dwarf_reg_to_regnum);
+  frame_unwind_append_sniffer (gdbarch, dwarf2_frame_sniffer);
+  frame_base_append_sniffer (gdbarch, dwarf2_frame_base_sniffer);
+#endif
+}
+
+void
+_initialize_hppa_linux_tdep (void)
+{
+  gdbarch_register_osabi (bfd_arch_hppa, 0, GDB_OSABI_LINUX, hppa_linux_init_abi);
+}