ILP32: GDB

gdb:

2017-03-06  Andrew Pinski  <apinski@cavium.com>
	    Steve Ellcey  <sellcey@cavium.com>
	    Yao Qi  <yao.qi@linaro.org>

	* aarch64-linux-nat.c (IS_ARM32): New macro.
	(fetch_gregs_from_thread): Use IS_ARM32 macro.
	(store_gregs_to_thread): Ditto.
	(fetch_fpregs_from_thread): Ditto.
	(store_fpregs_to_thread): Ditto.
	(ps_get_thread_area): Ditto.
	(aarch64_linux_siginfo_fixup): Ditto.
	* aarch64-linux-tdep.c (aarch64_linux_init_abi): Set link
	map offsets to 32 or 64 bits.
	* aarch64-tdep.c (aarch64_ilp32_register_type): New function.
	(aarch64_gdbarch_init): Setup ILP32 support.
	Make sure the gdbarches have compatible ilp32 flags.
	Set long and ptr sizes correctly for ilp32.
	* aarch64-tdep.h (gdbarch_tdep) <ilp32>: New field.

gdb/gdbserver:

2017-03-06  Andrew Pinski  <apinski@cavium.com>
	    Steve Ellcey  <sellcey@cavium.com>

	* linux-aarch64-low.c (aarch64_linux_read_description):

bfd/cpu-aarch64.c

@@ -25,7 +25,8 @@
 
 /* This routine is provided two arch_infos and works out which Aarch64
    machine which would be compatible with both and returns a pointer
-   to its info structure.  */
+   to its info structure.  ABI (ilp32 vs. lp64) and endianness compatibility
+   are checked in elfNN_aarch64_merge_private_bfd_data.  */
 
 static const bfd_arch_info_type *
 compatible (const bfd_arch_info_type * a, const bfd_arch_info_type * b)
@@ -38,10 +39,6 @@ compatible (const bfd_arch_info_type * a, const bfd_arch_info_type * b)
   if (a->mach == b->mach)
     return a;
 
-  /* Don't allow mixing ilp32 with lp64.  */
-  if ((a->mach & bfd_mach_aarch64_ilp32) != (b->mach & bfd_mach_aarch64_ilp32))
-    return NULL;
-
   /* Otherwise if either a or b is the 'default' machine
      then it can be polymorphed into the other.  */
   if (a->the_default)

bfd/elfnn-aarch64.c

@@ -6591,11 +6591,26 @@ elfNN_aarch64_merge_private_bfd_data (bfd *ibfd, struct bfd_link_info *info)
 
   /* Check if we have the same endianess.  */
   if (!_bfd_generic_verify_endian_match (ibfd, info))
-    return FALSE;
+    {
+      (*_bfd_error_handler)
+	(_("%B: endianness incompatible with that of the selected emulation"),
+	   ibfd);
+      return FALSE;
+    }
 
   if (!is_aarch64_elf (ibfd) || !is_aarch64_elf (obfd))
     return TRUE;
 
+  /* Don't allow mixing ilp32 with lp64.  */
+  if ((bfd_get_arch_info (ibfd)->mach & bfd_mach_aarch64_ilp32)
+      != (bfd_get_arch_info (obfd)->mach & bfd_mach_aarch64_ilp32))
+    {
+      (*_bfd_error_handler)
+	(_("%B: ABI is incompatible with that of the selected emulation: \"%s\" != \"%s\""),
+	 ibfd, bfd_get_target (ibfd), bfd_get_target (obfd));
+      return FALSE;
+    }
+
   /* The input BFD must have had its flags initialised.  */
   /* The following seems bogus to me -- The flags are initialized in
      the assembler but I don't think an elf_flags_init field is

bfd/elfxx-aarch64.c

@@ -548,7 +548,18 @@ _bfd_aarch64_elf_add_symbol_hook (bfd *abfd, struct bfd_link_info *info,
   return TRUE;
 }
 
-/* Support for core dump NOTE sections.  */
+/* Support for core dump NOTE sections.
+
+   note->descsz should be the size of elf_prstatus, defined in 
+   usr/include/linux/elfcore.h.  The size is 352 in ILP32 mode
+   and 392 in LP64 mode. elf_tdata (abfd)->core->signal is set from the
+   pr_cursig field of elf_prstatus which is at an offset of 12 in the
+   elf_prstatus structure in both ILP32 and LP64 modes.
+
+   elf_tdata (abfd)->core->lwpid is set from the pr_pid field of the
+   elf_prstatus structure.  It has an offset of 24 in ILP32 mode and
+   32 in LP64 mode due to two long fields in the structure that are in
+   front of the pr_pid field.  */
 
 bfd_boolean
 _bfd_aarch64_elf_grok_prstatus (bfd *abfd, Elf_Internal_Note *note)
@@ -561,14 +572,27 @@ _bfd_aarch64_elf_grok_prstatus (bfd *abfd, Elf_Internal_Note *note)
       default:
 	return FALSE;
 
-      case 392:		/* sizeof(struct elf_prstatus) on Linux/arm64.  */
+      case 352:	/* sizeof(struct elf_prstatus) on Linux/aarch64 ilp32.  */
 	/* pr_cursig */
 	elf_tdata (abfd)->core->signal
 	  = bfd_get_16 (abfd, note->descdata + 12);
 
 	/* pr_pid */
-	elf_tdata (abfd)->core->lwpid
-	  = bfd_get_32 (abfd, note->descdata + 32);
+	elf_tdata (abfd)->core->lwpid = bfd_get_32 (abfd, note->descdata + 24);
+
+	/* pr_reg */
+	offset = 72;
+	size = 272;
+
+	break;
+
+      case 392:	/* sizeof(struct elf_prstatus) on Linux/aarch64.  */
+	/* pr_cursig */
+	elf_tdata (abfd)->core->signal
+	  = bfd_get_16 (abfd, note->descdata + 12);
+
+	/* pr_pid */
+	elf_tdata (abfd)->core->lwpid = bfd_get_32 (abfd, note->descdata + 32);
 
 	/* pr_reg */
 	offset = 112;
@@ -590,12 +614,21 @@ _bfd_aarch64_elf_grok_psinfo (bfd *abfd, Elf_Internal_Note *note)
     default:
       return FALSE;
 
-    case 136:        /* This is sizeof(struct elf_prpsinfo) on Linux/aarch64.  */
+    case 124:         /* sizeof(struct elf_prpsinfo) on Linux/aarch64 ilp32.  */
+      elf_tdata (abfd)->core->pid = bfd_get_32 (abfd, note->descdata + 12);
+      elf_tdata (abfd)->core->program
+	= _bfd_elfcore_strndup (abfd, note->descdata + 28, 16);
+      elf_tdata (abfd)->core->command
+	= _bfd_elfcore_strndup (abfd, note->descdata + 44, 80);
+      break;
+
+    case 136:        /* sizeof(struct elf_prpsinfo) on Linux/aarch64.  */
       elf_tdata (abfd)->core->pid = bfd_get_32 (abfd, note->descdata + 24);
       elf_tdata (abfd)->core->program
 	= _bfd_elfcore_strndup (abfd, note->descdata + 40, 16);
       elf_tdata (abfd)->core->command
 	= _bfd_elfcore_strndup (abfd, note->descdata + 56, 80);
+      break;
     }
 
   /* Note that for some reason, a spurious space is tacked

gdb/aarch64-linux-nat.c

@@ -49,6 +49,10 @@
 #define TRAP_HWBKPT 0x0004
 #endif
 
+/* Check if we are on arm (as opposed to aarch64).  */
+#define IS_ARM32(gdbarch) \
+  (gdbarch_bfd_arch_info(gdbarch)->arch == bfd_arch_arm)
+
 /* Per-process data.  We don't bind this to a per-inferior registry
    because of targets like x86 GNU/Linux that need to keep track of
    processes that aren't bound to any inferior (e.g., fork children,
@@ -166,7 +170,7 @@ fetch_gregs_from_thread (struct regcache *regcache)
   tid = ptid_get_lwp (regcache_get_ptid (regcache));
 
   iovec.iov_base = &regs;
-  if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
+  if (IS_ARM32 (gdbarch))
     iovec.iov_len = 18 * 4;
   else
     iovec.iov_len = sizeof (regs);
@@ -175,7 +179,7 @@ fetch_gregs_from_thread (struct regcache *regcache)
   if (ret < 0)
     perror_with_name (_("Unable to fetch general registers."));
 
-  if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
+  if (IS_ARM32 (gdbarch))
     aarch32_gp_regcache_supply (regcache, (uint32_t *) regs, 1);
   else
     {
@@ -203,7 +207,7 @@ store_gregs_to_thread (const struct regcache *regcache)
   tid = ptid_get_lwp (regcache_get_ptid (regcache));
 
   iovec.iov_base = &regs;
-  if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
+  if (IS_ARM32 (gdbarch))
     iovec.iov_len = 18 * 4;
   else
     iovec.iov_len = sizeof (regs);
@@ -212,7 +216,7 @@ store_gregs_to_thread (const struct regcache *regcache)
   if (ret < 0)
     perror_with_name (_("Unable to fetch general registers."));
 
-  if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
+  if (IS_ARM32 (gdbarch))
     aarch32_gp_regcache_collect (regcache, (uint32_t *) regs, 1);
   else
     {
@@ -248,7 +252,7 @@ fetch_fpregs_from_thread (struct regcache *regcache)
 
   iovec.iov_base = &regs;
 
-  if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
+  if (IS_ARM32 (gdbarch))
     {
       iovec.iov_len = VFP_REGS_SIZE;
 
@@ -295,7 +299,7 @@ store_fpregs_to_thread (const struct regcache *regcache)
 
   iovec.iov_base = &regs;
 
-  if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
+  if (IS_ARM32 (gdbarch))
     {
       iovec.iov_len = VFP_REGS_SIZE;
 
@@ -328,7 +332,7 @@ store_fpregs_to_thread (const struct regcache *regcache)
 			      (char *) &regs.fpcr);
     }
 
-  if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
+  if (IS_ARM32 (gdbarch))
     {
       ret = ptrace (PTRACE_SETREGSET, tid, NT_ARM_VFP, &iovec);
       if (ret < 0)
@@ -460,10 +464,9 @@ ps_err_e
 ps_get_thread_area (struct ps_prochandle *ph,
 		    lwpid_t lwpid, int idx, void **base)
 {
-  int is_64bit_p
-    = (gdbarch_bfd_arch_info (target_gdbarch ())->bits_per_word == 64);
+  int is_aarch64_p = !IS_ARM32 (target_gdbarch ());
 
-  return aarch64_ps_get_thread_area (ph, lwpid, idx, base, is_64bit_p);
+  return aarch64_ps_get_thread_area (ph, lwpid, idx, base, is_aarch64_p);
 }
 
 
@@ -517,7 +520,7 @@ aarch64_linux_siginfo_fixup (siginfo_t *native, gdb_byte *inf, int direction)
 
   /* Is the inferior 32-bit?  If so, then do fixup the siginfo
      object.  */
-  if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
+  if (IS_ARM32 (gdbarch))
     {
       if (direction == 0)
 	aarch64_compat_siginfo_from_siginfo ((struct compat_siginfo *) inf,

gdb/aarch64-linux-tdep.c

@@ -131,13 +131,13 @@
   ucontext.uc_mcontext.  */
 
 /* These magic numbers need to reflect the layout of the kernel
-   defined struct rt_sigframe and ucontext.  */
+   defined struct rt_sigframe and ucontext in LP64 mode.  */
 #define AARCH64_SIGCONTEXT_REG_SIZE             8
 #define AARCH64_RT_SIGFRAME_UCONTEXT_OFFSET     128
 #define AARCH64_UCONTEXT_SIGCONTEXT_OFFSET      176
 #define AARCH64_SIGCONTEXT_XO_OFFSET            8
 
-/* Implement the "init" method of struct tramp_frame.  */
+/* Implement the "init" method of struct tramp_frame for LP64.  */
 
 static void
 aarch64_linux_sigframe_init (const struct tramp_frame *self,
@@ -186,6 +186,62 @@ static const struct tramp_frame aarch64_linux_rt_sigframe =
   aarch64_linux_sigframe_init
 };
 
+/* These magic numbers need to reflect the layout of the kernel
+   defined struct rt_sigframe and ucontext in LP64 mode.  */
+#define AARCH64_ILP32_SIGCONTEXT_REG_SIZE             8
+#define AARCH64_ILP32_RT_SIGFRAME_UCONTEXT_OFFSET     128
+#define AARCH64_ILP32_UCONTEXT_SIGCONTEXT_OFFSET      160
+#define AARCH64_ILP32_SIGCONTEXT_XO_OFFSET            8
+
+/* Implement the "init" method of struct tramp_frame for ILP32.  */
+
+static void
+aarch64_ilp32_linux_sigframe_init (const struct tramp_frame *self,
+				   struct frame_info *this_frame,
+				   struct trad_frame_cache *this_cache,
+				   CORE_ADDR func)
+{
+  CORE_ADDR sp = get_frame_register_unsigned (this_frame, AARCH64_SP_REGNUM);
+  CORE_ADDR sigcontext_addr =
+    sp
+    + AARCH64_RT_SIGFRAME_UCONTEXT_OFFSET
+    + AARCH64_ILP32_UCONTEXT_SIGCONTEXT_OFFSET;
+  int i;
+
+  for (i = 0; i < 31; i++)
+    {
+      trad_frame_set_reg_addr (this_cache,
+			       AARCH64_X0_REGNUM + i,
+			       sigcontext_addr + AARCH64_SIGCONTEXT_XO_OFFSET
+			       + i * AARCH64_SIGCONTEXT_REG_SIZE);
+    }
+  trad_frame_set_reg_addr (this_cache, AARCH64_SP_REGNUM,
+			   sigcontext_addr + AARCH64_SIGCONTEXT_XO_OFFSET
+			     + 31 * AARCH64_SIGCONTEXT_REG_SIZE);
+  trad_frame_set_reg_addr (this_cache, AARCH64_PC_REGNUM,
+			   sigcontext_addr + AARCH64_SIGCONTEXT_XO_OFFSET
+			     + 32 * AARCH64_SIGCONTEXT_REG_SIZE);
+
+  trad_frame_set_id (this_cache, frame_id_build (sp, func));
+}
+
+static const struct tramp_frame aarch64_ilp32_linux_rt_sigframe =
+{
+  SIGTRAMP_FRAME,
+  4,
+  {
+    /* movz x8, 0x8b (S=1,o=10,h=0,i=0x8b,r=8)
+       Soo1 0010 1hhi iiii iiii iiii iiir rrrr  */
+    {0xd2801168, -1},
+
+    /* svc  0x0      (o=0, l=1)
+       1101 0100 oooi iiii iiii iiii iii0 00ll  */
+    {0xd4000001, -1},
+    {TRAMP_SENTINEL_INSN, -1}
+  },
+  aarch64_ilp32_linux_sigframe_init
+};
+
 /* Register maps.  */
 
 static const struct regcache_map_entry aarch64_linux_gregmap[] =
@@ -1016,8 +1072,12 @@ aarch64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 
   linux_init_abi (info, gdbarch);
 
-  set_solib_svr4_fetch_link_map_offsets (gdbarch,
-					 svr4_lp64_fetch_link_map_offsets);
+  if (tdep->ilp32)
+    set_solib_svr4_fetch_link_map_offsets (gdbarch,
+					   svr4_ilp32_fetch_link_map_offsets);
+  else
+    set_solib_svr4_fetch_link_map_offsets (gdbarch,
+					   svr4_lp64_fetch_link_map_offsets);
 
   /* Enable TLS support.  */
   set_gdbarch_fetch_tls_load_module_address (gdbarch,
@@ -1027,7 +1087,10 @@ aarch64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
   set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
   set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver);
 
-  tramp_frame_prepend_unwinder (gdbarch, &aarch64_linux_rt_sigframe);
+  if (tdep->ilp32)
+    tramp_frame_prepend_unwinder (gdbarch, &aarch64_ilp32_linux_rt_sigframe);
+  else
+    tramp_frame_prepend_unwinder (gdbarch, &aarch64_linux_rt_sigframe);
 
   /* Enable longjmp.  */
   tdep->jb_pc = 11;

gdb/aarch64-tdep.c

@@ -2086,6 +2086,22 @@ aarch64_gen_return_address (struct gdbarch *gdbarch,
 }
 
 
+/* Implement the "register_type" gdbarch method.
+   Adjust the register type of $PC and $SP on ILP32.  */
+
+static struct type *
+aarch64_ilp32_register_type (struct gdbarch *gdbarch, int regnum)
+{
+  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+
+  gdb_assert (tdep->ilp32);
+
+  if (regnum == AARCH64_SP_REGNUM || regnum == AARCH64_PC_REGNUM)
+    return builtin_type (gdbarch)->builtin_uint64;
+  else
+    return tdesc_register_type (gdbarch, regnum);
+}
+
 /* Return the pseudo register name corresponding to register regnum.  */
 
 static const char *
@@ -2848,6 +2864,10 @@ aarch64_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   const struct tdesc_feature *feature;
   int num_regs = 0;
   int num_pseudo_regs = 0;
+  bool ilp32 = false;
+
+  if (info.bfd_arch_info->mach == bfd_mach_aarch64_ilp32)
+    ilp32 = true;
 
   /* Ensure we always have a target descriptor.  */
   if (!tdesc_has_registers (tdesc))
@@ -2905,6 +2925,9 @@ aarch64_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
        best_arch != NULL;
        best_arch = gdbarch_list_lookup_by_info (best_arch->next, &info))
     {
+      /* ILP32 and LP64 are incompatible. */
+      if (gdbarch_tdep (arches->gdbarch)->ilp32 != ilp32)
+	continue;
       /* Found a match.  */
       break;
     }
@@ -2923,6 +2946,7 @@ aarch64_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   tdep->lowest_pc = 0x20;
   tdep->jb_pc = -1;		/* Longjump support not enabled by default.  */
   tdep->jb_elt_size = 8;
+  tdep->ilp32 = ilp32;
 
   set_gdbarch_push_dummy_call (gdbarch, aarch64_push_dummy_call);
   set_gdbarch_frame_align (gdbarch, aarch64_frame_align);
@@ -2965,9 +2989,9 @@ aarch64_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   set_gdbarch_float_bit (gdbarch, 32);
   set_gdbarch_double_bit (gdbarch, 64);
   set_gdbarch_long_double_bit (gdbarch, 128);
-  set_gdbarch_long_bit (gdbarch, 64);
+  set_gdbarch_long_bit (gdbarch, ilp32 ? 32 : 64);
   set_gdbarch_long_long_bit (gdbarch, 64);
-  set_gdbarch_ptr_bit (gdbarch, 64);
+  set_gdbarch_ptr_bit (gdbarch, ilp32 ? 32 : 64);
   set_gdbarch_char_signed (gdbarch, 0);
   set_gdbarch_wchar_signed (gdbarch, 0);
   set_gdbarch_float_format (gdbarch, floatformats_ieee_single);
@@ -3010,6 +3034,13 @@ aarch64_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 
   tdesc_use_registers (gdbarch, tdesc, tdesc_data);
 
+  if (ilp32)
+    {
+      /* Override tdesc_register_type to adjust the types of $PC and
+	 $SP in ILP32.  */
+      set_gdbarch_register_type (gdbarch, aarch64_ilp32_register_type);
+    }
+
   /* Add standard register aliases.  */
   for (i = 0; i < ARRAY_SIZE (aarch64_register_aliases); i++)
     user_reg_add (gdbarch, aarch64_register_aliases[i].name,

gdb/aarch64-tdep.h

@@ -97,6 +97,9 @@ struct gdbarch_tdep
 
   /* syscall record.  */
   int (*aarch64_syscall_record) (struct regcache *regcache, unsigned long svc_number);
+  /* If this is ILP32 or LP64.  */
+  bool ilp32;
+
 };
 
 extern struct target_desc *tdesc_aarch64;

gdb/gdbserver/linux-aarch64-low.c

@@ -492,7 +492,12 @@ aarch64_linux_read_description (void)
 
   is_elf64 = linux_pid_exe_is_elf_64_file (tid, &machine);
 
-  if (is_elf64)
+  /* There are problems with ptrace when gdbserver is 32 bits and the
+     program being debugged is 64 bits.  */
+  if (sizeof (void *) == 4 && is_elf64)
+    error (_("Can't debug 64-bit process with 32-bit GDBserver"));
+
+  if (machine == EM_AARCH64)
     return tdesc_aarch64;
   else
     return tdesc_arm_with_neon;