Add gdbarch hooks to detect and return tagged addresses

This patch adds a couple gdbarch hooks: gdbarch_tagged_address_p checks if a particular address is tagged or not. gdbarch_address_tag returns the tag for a particular address, if tagged. I've used struct value as opposed to straight CORE_ADDR so other architectures can use the infrastructure without having to rely on fixed types. gdb/ChangeLog: YYYY-MM-DD Luis Machado <luis.machado@linaro.org> * aarch64-linux-tdep.c: Include target.h, arch-utils.h, value.h and arch/aarch64-linux.h. (make_ltag_bits, make_ltag, aarch64_linux_set_ltag) (aarch64_linux_get_ltag, aarch64_linux_get_atag) (value_valid_for_memtag, aarch64_linux_tagged_address_p) (aarch64_linux_memtag_mismatch_p, aarch64_linux_set_memtags) (aarch64_linux_get_memtag, aarch64_linux_memtag_to_string): New functions. (aarch64_linux_init_abi): Initialize MTE-related gdbarch hooks. * arch-utils.c (default_memtag_to_string, +default_tagged_address_p) (default_memtag_mismatch_p, default_set_memtags) (default_get_memtag): New functions. * arch-utils.h (default_memtag_to_string, default_tagged_address_p) (default_memtag_mismatch_p, default_set_memtags) (default_get_memtag): New prototypes. * arch/aarch64-linux.h (MTE_LOGICAL_TAG_START_BIT): Define. (MTE_LOGICAL_MAX_VALUE): Define. * gdbarch.c: Regenerate. * gdbarch.h: Regenerate. * gdbarch.sh (memtag_to_string, tagged_address_p, memtag_mismatch_p) (set_memtags, get_memtag, memtag_granule_size): New gdbarch hooks. (enum memtag_type): New enum.
2025-12-26 09:08:59 +00:00 · 2020-06-15 15:01:14 -03:00
parent 25d36f4a5b
commit 2c7d3af06c
7 changed files with 567 additions and 0 deletions
--- a/gdb/aarch64-linux-tdep.c
+++ b/gdb/aarch64-linux-tdep.c
@@ -30,6 +30,7 @@
 #include "symtab.h"
 #include "tramp-frame.h"
 #include "trad-frame.h"
+#include "target.h"
 #include "target/target.h"

 #include "regcache.h"
@@ -46,6 +47,11 @@

 #include "arch/aarch64-linux.h"

+#include "arch-utils.h"
+#include "value.h"
+
+#include "arch/aarch64-linux.h"
+
 /* Signal frame handling.

      +------------+  ^
@@ -1457,6 +1463,241 @@ aarch64_linux_gcc_target_options (struct gdbarch *gdbarch)
  return {};
 }

+/* Return the 4-bit tag made from VALUE.  */
+
+static CORE_ADDR
+make_ltag_bits (CORE_ADDR value)
+{
+  return value & MTE_LOGICAL_MAX_VALUE;
+}
+
+/* Return the 4-bit tag that can be OR-ed to an address.  */
+
+static CORE_ADDR
+make_ltag (CORE_ADDR value)
+{
+  return make_ltag_bits (value) << MTE_LOGICAL_TAG_START_BIT;
+}
+
+/* Helper to set the logical TAG for a 64-bit ADDRESS.
+
+   It is always possible to set the logical tag.  */
+
+static CORE_ADDR
+aarch64_linux_set_ltag (CORE_ADDR address, CORE_ADDR tag)
+{
+  /* Remove the existing tag.  */
+  address &= ~make_ltag (MTE_LOGICAL_MAX_VALUE);
+
+  /* Return the new tagged address.  */
+  return address | make_ltag (tag);
+}
+
+/* Helper to get the logical tag from a 64-bit ADDRESS.
+
+   It is always possible to get the logical tag.  */
+
+static CORE_ADDR
+aarch64_linux_get_ltag (CORE_ADDR address)
+{
+  return make_ltag_bits (address >> MTE_LOGICAL_TAG_START_BIT);
+}
+
+/* Helper to get the allocation tag from a 64-bit ADDRESS.
+
+   Return 0 for success and non-zero otherwise.  */
+
+static int
+aarch64_linux_get_atag (CORE_ADDR address, CORE_ADDR *tag)
+{
+  gdb::byte_vector tags;
+
+  /* Attempt to fetch the allocation tag.  */
+  if (target_fetch_memtags (address, 0, tags) != 0)
+    return 1;
+
+  /* Empty tag vector is an error.  */
+  if (tags.empty ())
+    return 1;
+
+  /* Although our tags are 4 bits in size, they are stored in a
+     byte.  */
+  *tag = tags[0];
+
+  return 0;
+}
+
+/* Helper to validate VALUE for a memtag operation.  */
+
+static bool
+value_valid_for_memtag (struct value *value)
+{
+  if (value != nullptr && VALUE_LVAL (value) == not_lval
+      && value_contents_raw (value) != nullptr)
+    return true;
+
+  return false;
+}
+
+/* Implement the tagged_address_p gdbarch method.  */
+
+static bool
+aarch64_linux_tagged_address_p (struct gdbarch *gdbarch, struct value *address)
+{
+  if (!value_valid_for_memtag (address))
+    return false;
+
+  CORE_ADDR addr = value_as_address (address);
+
+  /* Check if the page that contains ADDRESS is mapped with PROT_MTE.  */
+  if (!linux_address_in_memtag_page (addr))
+    return false;
+
+  /* We have a valid tag in the top byte of the 64-bit address.  */
+  return true;
+}
+
+/* Implement the memtag_mismatch_p gdbarch method.  */
+
+static bool
+aarch64_linux_memtag_mismatch_p (struct gdbarch *gdbarch,
+				 struct value *address)
+{
+  if (!value_valid_for_memtag (address))
+    return false;
+
+  /* Make sure we are dealing with a tagged address to begin with.  */
+  if (!aarch64_linux_tagged_address_p (gdbarch, address))
+    return false;
+
+  CORE_ADDR addr = value_as_address (address);
+
+  /* Fetch the allocation tag for ADDRESS.  */
+  CORE_ADDR atag = 0;
+
+  if (aarch64_linux_get_atag (addr, &atag) != 0)
+    return false;
+
+  /* Fetch the logical tag for ADDRESS.  */
+  gdb_byte ltag = aarch64_linux_get_ltag (addr);
+
+  /* Are the tags the same?  */
+  if (ltag == atag)
+    return false;
+
+  return true;
+}
+
+/* Implement the set_memtags gdbarch method.  */
+
+static int
+aarch64_linux_set_memtags (struct gdbarch *gdbarch, struct value *address,
+			   size_t length, const gdb::byte_vector &tags,
+			   enum memtag_type tag_type)
+{
+  if (!value_valid_for_memtag (address))
+    return 1;
+
+  /* Make sure we are dealing with a tagged address to begin with.  */
+  if (!aarch64_linux_tagged_address_p (gdbarch, address))
+    return 1;
+
+  CORE_ADDR addr = value_as_address (address);
+
+  /* Set the logical tag or the allocation tag.  */
+  if (tag_type == tag_logical)
+    {
+      /* When setting logical tags, we don't care about the length, since
+	 we are only setting a single logical tag.  */
+      addr = aarch64_linux_set_ltag (addr, tags[0]);
+
+      /* Update the value's content with the tag.  */
+      enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+      gdb_byte *srcbuf = value_contents_raw (address);
+      store_unsigned_integer (srcbuf, sizeof (addr), byte_order, addr);
+    }
+  else
+    {
+      /* With G being the number of tag granules and N the number of tags
+	 passed in, we can have the following cases:
+
+	 1 - G == N: Store all the N tags to memory.
+
+	 2 - G < N : Warn about having more tags than granules, but write G
+		     tags.
+
+	 3 - G > N : This is a "fill tags" operation.  We should use the tags
+		     as a pattern to fill the granules repeatedly until we have
+		     written G tags to memory.
+      */
+
+      size_t g = get_tag_granules (addr, length, MTE_GRANULE_SIZE);
+      size_t n = tags.size ();
+
+      if (g < n)
+	{
+	  warning (_("Got more tags than memory granules.  Tags will be "
+		     "truncated."));
+	}
+      else if (g > n)
+	warning (_("Using tag pattern to fill memory range."));
+
+      if (target_store_memtags (addr, length, tags) != 0)
+	return 1;
+    }
+  return 0;
+}
+
+/* Implement the get_memtag gdbarch method.  */
+
+static struct value *
+aarch64_linux_get_memtag (struct gdbarch *gdbarch, struct value *address,
+			  enum memtag_type tag_type)
+{
+  if (!value_valid_for_memtag (address))
+    return nullptr;
+
+  /* Make sure we are dealing with a tagged address to begin with.  */
+  if (!aarch64_linux_tagged_address_p (gdbarch, address))
+    return nullptr;
+
+  CORE_ADDR addr = value_as_address (address);
+  CORE_ADDR tag = 0;
+
+  /* Get the logical tag or the allocation tag.  */
+  if (tag_type == tag_logical)
+    tag = aarch64_linux_get_ltag (addr);
+  else
+    {
+      if (aarch64_linux_get_atag (addr, &tag) != 0)
+	return nullptr;
+    }
+
+  /* Convert the tag to a value.  */
+  return value_from_ulongest (builtin_type (gdbarch)->builtin_unsigned_int,
+			      tag);
+}
+
+/* Implement the memtag_to_string gdbarch method.  */
+
+static std::string
+aarch64_linux_memtag_to_string (struct gdbarch *gdbarch,
+				struct value *address,
+				enum memtag_type tag_type)
+{
+  if (!value_valid_for_memtag (address))
+    return "";
+
+  struct value *v_tag = aarch64_linux_get_memtag (gdbarch, address, tag_type);
+
+  if (v_tag == nullptr && tag_allocation)
+    error (_("Error getting tag from target"));
+
+  CORE_ADDR tag = value_as_address (v_tag);
+
+  return string_printf ("0x%s", phex_nz (tag, sizeof (tag)));
+}
+
 static void
 aarch64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
@@ -1514,6 +1755,31 @@ aarch64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
     data associated with the address.  */
  set_gdbarch_significant_addr_bit (gdbarch, 56);

+  /* MTE-specific settings and hooks.  */
+  if (tdep->has_mte ())
+    {
+      /* Register a hook for checking if an address is tagged or not.  */
+      set_gdbarch_tagged_address_p (gdbarch, aarch64_linux_tagged_address_p);
+
+      /* Register a hook for checking if there is a memory tag mismatch.  */
+      set_gdbarch_memtag_mismatch_p (gdbarch,
+				     aarch64_linux_memtag_mismatch_p);
+
+      /* Register a hook for setting the logical/allocation tags for
+	 a range of addresses.  */
+      set_gdbarch_set_memtags (gdbarch, aarch64_linux_set_memtags);
+
+      /* Register a hook for extracting the logical/allocation tag from an
+	 address.  */
+      set_gdbarch_get_memtag (gdbarch, aarch64_linux_get_memtag);
+
+      /* Set the allocation tag granule size to 16 bytes.  */
+      set_gdbarch_memtag_granule_size (gdbarch, MTE_GRANULE_SIZE);
+
+      /* Register a hook for converting a memory tag to a string.  */
+      set_gdbarch_memtag_to_string (gdbarch, aarch64_linux_memtag_to_string);
+    }
+
  /* Initialize the aarch64_linux_record_tdep.  */
  /* These values are the size of the type that will be used in a system
     call.  They are obtained from Linux Kernel source.  */
--- a/gdb/arch-utils.c
+++ b/gdb/arch-utils.c
@@ -78,6 +78,56 @@ legacy_register_sim_regno (struct gdbarch *gdbarch, int regnum)
    return LEGACY_SIM_REGNO_IGNORE;
 }

+
+/* See arch-utils.h */
+
+std::string
+default_memtag_to_string (struct gdbarch *gdbarch, struct value *address,
+			  enum memtag_type tag_type)
+{
+  /* By default, assume the address is untagged.  */
+  return "";
+}
+
+/* See arch-utils.h */
+
+bool
+default_tagged_address_p (struct gdbarch *gdbarch, struct value *address)
+{
+  /* By default, assume the address is untagged.  */
+  return false;
+}
+
+/* See arch-utils.h */
+
+bool
+default_memtag_mismatch_p (struct gdbarch *gdbarch, struct value *address)
+{
+  /* By default, assume there is no mismatch.  */
+  return false;
+}
+
+/* See arch-utils.h */
+
+int
+default_set_memtags (struct gdbarch *gdbarch, struct value *address,
+		     size_t length, const gdb::byte_vector &tags,
+		     enum memtag_type tag_type)
+{
+  /* By default, return 0;  */
+  return 0;
+}
+
+/* See arch-utils.h */
+
+struct value *
+default_get_memtag (struct gdbarch *gdbarch, struct value *address,
+		    enum memtag_type tag_type)
+{
+  /* By default, return no tag.  */
+  return NULL;
+}
+
 CORE_ADDR
 generic_skip_trampoline_code (struct frame_info *frame, CORE_ADDR pc)
 {
--- a/gdb/arch-utils.h
+++ b/gdb/arch-utils.h
@@ -134,6 +134,29 @@ extern const struct floatformat **
  default_floatformat_for_type (struct gdbarch *gdbarch,
 				const char *name, int len);

+/* Default implementation of gdbarch_tagged_address_p.  */
+extern std::string default_memtag_to_string (struct gdbarch *gdbarch,
+					     struct value *address,
+					     enum memtag_type tag_type);
+
+/* Default implementation of gdbarch_tagged_address_p.  */
+bool default_tagged_address_p (struct gdbarch *gdbarch, struct value *address);
+
+/* Default implementation of gdbarch_memtag_mismatch_p.  */
+extern bool default_memtag_mismatch_p (struct gdbarch *gdbarch,
+				       struct value *address);
+
+/* Default implementation of gdbarch_set_memtags.  */
+int default_set_memtags (struct gdbarch *gdbarch,
+			 struct value *address, size_t length,
+			 const gdb::byte_vector &tags,
+			 enum memtag_type tag_type);
+
+/* Default implementation of gdbarch_get_memtag.  */
+struct value *default_get_memtag (struct gdbarch *gdbarch,
+				  struct value *address,
+				  enum memtag_type tag_type);
+
 extern CORE_ADDR generic_skip_trampoline_code (struct frame_info *frame,
 					       CORE_ADDR pc);

--- a/gdb/arch/aarch64-linux.h
+++ b/gdb/arch/aarch64-linux.h
@@ -32,6 +32,8 @@

 /* We have one tag per 16 bytes of memory.  */
 #define MTE_GRANULE_SIZE 16
+#define MTE_LOGICAL_TAG_START_BIT   56
+#define MTE_LOGICAL_MAX_VALUE	    0xf

 /* Return the number of tag granules in the memory range
   [ADDR, ADDR + LEN) given GRANULE_SIZE.  */
--- a/gdb/gdbarch.c
+++ b/gdb/gdbarch.c
@@ -251,6 +251,12 @@ struct gdbarch
  gdbarch_convert_from_func_ptr_addr_ftype *convert_from_func_ptr_addr;
  gdbarch_addr_bits_remove_ftype *addr_bits_remove;
  int significant_addr_bit;
+  gdbarch_memtag_to_string_ftype *memtag_to_string;
+  gdbarch_tagged_address_p_ftype *tagged_address_p;
+  gdbarch_memtag_mismatch_p_ftype *memtag_mismatch_p;
+  gdbarch_set_memtags_ftype *set_memtags;
+  gdbarch_get_memtag_ftype *get_memtag;
+  CORE_ADDR memtag_granule_size;
  gdbarch_software_single_step_ftype *software_single_step;
  gdbarch_single_step_through_delay_ftype *single_step_through_delay;
  gdbarch_print_insn_ftype *print_insn;
@@ -427,6 +433,11 @@ gdbarch_alloc (const struct gdbarch_info *info,
  gdbarch->stabs_argument_has_addr = default_stabs_argument_has_addr;
  gdbarch->convert_from_func_ptr_addr = convert_from_func_ptr_addr_identity;
  gdbarch->addr_bits_remove = core_addr_identity;
+  gdbarch->memtag_to_string = default_memtag_to_string;
+  gdbarch->tagged_address_p = default_tagged_address_p;
+  gdbarch->memtag_mismatch_p = default_memtag_mismatch_p;
+  gdbarch->set_memtags = default_set_memtags;
+  gdbarch->get_memtag = default_get_memtag;
  gdbarch->print_insn = default_print_insn;
  gdbarch->skip_trampoline_code = generic_skip_trampoline_code;
  gdbarch->skip_solib_resolver = generic_skip_solib_resolver;
@@ -616,6 +627,12 @@ verify_gdbarch (struct gdbarch *gdbarch)
  /* Skip verify of convert_from_func_ptr_addr, invalid_p == 0 */
  /* Skip verify of addr_bits_remove, invalid_p == 0 */
  /* Skip verify of significant_addr_bit, invalid_p == 0 */
+  /* Skip verify of memtag_to_string, invalid_p == 0 */
+  /* Skip verify of tagged_address_p, invalid_p == 0 */
+  /* Skip verify of memtag_mismatch_p, invalid_p == 0 */
+  /* Skip verify of set_memtags, invalid_p == 0 */
+  /* Skip verify of get_memtag, invalid_p == 0 */
+  /* Skip verify of memtag_granule_size, invalid_p == 0 */
  /* Skip verify of software_single_step, has predicate.  */
  /* Skip verify of single_step_through_delay, has predicate.  */
  /* Skip verify of print_insn, invalid_p == 0 */
@@ -1055,6 +1072,9 @@ gdbarch_dump (struct gdbarch *gdbarch, struct ui_file *file)
  fprintf_unfiltered (file,
                      "gdbarch_dump: get_longjmp_target = <%s>\n",
                      host_address_to_string (gdbarch->get_longjmp_target));
+  fprintf_unfiltered (file,
+                      "gdbarch_dump: get_memtag = <%s>\n",
+                      host_address_to_string (gdbarch->get_memtag));
  fprintf_unfiltered (file,
                      "gdbarch_dump: get_pc_address_flags = <%s>\n",
                      host_address_to_string (gdbarch->get_pc_address_flags));
@@ -1190,6 +1210,15 @@ gdbarch_dump (struct gdbarch *gdbarch, struct ui_file *file)
  fprintf_unfiltered (file,
                      "gdbarch_dump: memory_remove_breakpoint = <%s>\n",
                      host_address_to_string (gdbarch->memory_remove_breakpoint));
+  fprintf_unfiltered (file,
+                      "gdbarch_dump: memtag_granule_size = %s\n",
+                      core_addr_to_string_nz (gdbarch->memtag_granule_size));
+  fprintf_unfiltered (file,
+                      "gdbarch_dump: memtag_mismatch_p = <%s>\n",
+                      host_address_to_string (gdbarch->memtag_mismatch_p));
+  fprintf_unfiltered (file,
+                      "gdbarch_dump: memtag_to_string = <%s>\n",
+                      host_address_to_string (gdbarch->memtag_to_string));
  fprintf_unfiltered (file,
                      "gdbarch_dump: num_pseudo_regs = %s\n",
                      plongest (gdbarch->num_pseudo_regs));
@@ -1334,6 +1363,9 @@ gdbarch_dump (struct gdbarch *gdbarch, struct ui_file *file)
  fprintf_unfiltered (file,
                      "gdbarch_dump: sdb_reg_to_regnum = <%s>\n",
                      host_address_to_string (gdbarch->sdb_reg_to_regnum));
+  fprintf_unfiltered (file,
+                      "gdbarch_dump: set_memtags = <%s>\n",
+                      host_address_to_string (gdbarch->set_memtags));
  fprintf_unfiltered (file,
                      "gdbarch_dump: short_bit = %s\n",
                      plongest (gdbarch->short_bit));
@@ -1448,6 +1480,9 @@ gdbarch_dump (struct gdbarch *gdbarch, struct ui_file *file)
  fprintf_unfiltered (file,
                      "gdbarch_dump: syscalls_info = %s\n",
                      host_address_to_string (gdbarch->syscalls_info));
+  fprintf_unfiltered (file,
+                      "gdbarch_dump: tagged_address_p = <%s>\n",
+                      host_address_to_string (gdbarch->tagged_address_p));
  fprintf_unfiltered (file,
                      "gdbarch_dump: target_desc = %s\n",
                      host_address_to_string (gdbarch->target_desc));
@@ -3220,6 +3255,108 @@ set_gdbarch_significant_addr_bit (struct gdbarch *gdbarch,
  gdbarch->significant_addr_bit = significant_addr_bit;
 }

+std::string
+gdbarch_memtag_to_string (struct gdbarch *gdbarch, struct value *address, enum memtag_type tag_type)
+{
+  gdb_assert (gdbarch != NULL);
+  gdb_assert (gdbarch->memtag_to_string != NULL);
+  if (gdbarch_debug >= 2)
+    fprintf_unfiltered (gdb_stdlog, "gdbarch_memtag_to_string called\n");
+  return gdbarch->memtag_to_string (gdbarch, address, tag_type);
+}
+
+void
+set_gdbarch_memtag_to_string (struct gdbarch *gdbarch,
+                              gdbarch_memtag_to_string_ftype memtag_to_string)
+{
+  gdbarch->memtag_to_string = memtag_to_string;
+}
+
+bool
+gdbarch_tagged_address_p (struct gdbarch *gdbarch, struct value *address)
+{
+  gdb_assert (gdbarch != NULL);
+  gdb_assert (gdbarch->tagged_address_p != NULL);
+  if (gdbarch_debug >= 2)
+    fprintf_unfiltered (gdb_stdlog, "gdbarch_tagged_address_p called\n");
+  return gdbarch->tagged_address_p (gdbarch, address);
+}
+
+void
+set_gdbarch_tagged_address_p (struct gdbarch *gdbarch,
+                              gdbarch_tagged_address_p_ftype tagged_address_p)
+{
+  gdbarch->tagged_address_p = tagged_address_p;
+}
+
+bool
+gdbarch_memtag_mismatch_p (struct gdbarch *gdbarch, struct value *address)
+{
+  gdb_assert (gdbarch != NULL);
+  gdb_assert (gdbarch->memtag_mismatch_p != NULL);
+  if (gdbarch_debug >= 2)
+    fprintf_unfiltered (gdb_stdlog, "gdbarch_memtag_mismatch_p called\n");
+  return gdbarch->memtag_mismatch_p (gdbarch, address);
+}
+
+void
+set_gdbarch_memtag_mismatch_p (struct gdbarch *gdbarch,
+                               gdbarch_memtag_mismatch_p_ftype memtag_mismatch_p)
+{
+  gdbarch->memtag_mismatch_p = memtag_mismatch_p;
+}
+
+int
+gdbarch_set_memtags (struct gdbarch *gdbarch, struct value *address, size_t length, const gdb::byte_vector &tags, enum memtag_type tag_type)
+{
+  gdb_assert (gdbarch != NULL);
+  gdb_assert (gdbarch->set_memtags != NULL);
+  if (gdbarch_debug >= 2)
+    fprintf_unfiltered (gdb_stdlog, "gdbarch_set_memtags called\n");
+  return gdbarch->set_memtags (gdbarch, address, length, tags, tag_type);
+}
+
+void
+set_gdbarch_set_memtags (struct gdbarch *gdbarch,
+                         gdbarch_set_memtags_ftype set_memtags)
+{
+  gdbarch->set_memtags = set_memtags;
+}
+
+struct value *
+gdbarch_get_memtag (struct gdbarch *gdbarch, struct value *address, enum memtag_type tag_type)
+{
+  gdb_assert (gdbarch != NULL);
+  gdb_assert (gdbarch->get_memtag != NULL);
+  if (gdbarch_debug >= 2)
+    fprintf_unfiltered (gdb_stdlog, "gdbarch_get_memtag called\n");
+  return gdbarch->get_memtag (gdbarch, address, tag_type);
+}
+
+void
+set_gdbarch_get_memtag (struct gdbarch *gdbarch,
+                        gdbarch_get_memtag_ftype get_memtag)
+{
+  gdbarch->get_memtag = get_memtag;
+}
+
+CORE_ADDR
+gdbarch_memtag_granule_size (struct gdbarch *gdbarch)
+{
+  gdb_assert (gdbarch != NULL);
+  /* Skip verify of memtag_granule_size, invalid_p == 0 */
+  if (gdbarch_debug >= 2)
+    fprintf_unfiltered (gdb_stdlog, "gdbarch_memtag_granule_size called\n");
+  return gdbarch->memtag_granule_size;
+}
+
+void
+set_gdbarch_memtag_granule_size (struct gdbarch *gdbarch,
+                                 CORE_ADDR memtag_granule_size)
+{
+  gdbarch->memtag_granule_size = memtag_granule_size;
+}
+
 int
 gdbarch_software_single_step_p (struct gdbarch *gdbarch)
 {
--- a/gdb/gdbarch.h
+++ b/gdb/gdbarch.h
@@ -115,6 +115,18 @@ enum function_call_return_method
  return_method_struct,
 };

+enum memtag_type
+{
+  /* Logical tag, the tag that is stored in unused bits of a pointer to a
+     virtual address.  */
+  tag_logical = 0,
+
+  /* Allocation tag, the tag that is associated with every granule of memory in
+     the physical address space.  Allocation tags are used to validate memory
+     accesses via pointers containing logical tags.  */
+  tag_allocation,
+};
+


 /* The following are pre-initialized by GDBARCH.  */
@@ -705,6 +717,47 @@ extern void set_gdbarch_addr_bits_remove (struct gdbarch *gdbarch, gdbarch_addr_
 extern int gdbarch_significant_addr_bit (struct gdbarch *gdbarch);
 extern void set_gdbarch_significant_addr_bit (struct gdbarch *gdbarch, int significant_addr_bit);

+/* Return a string representation of the memory tag TYPE of ADDRESS.
+   If no tag is associated with such an address, return the empty string. */
+
+typedef std::string (gdbarch_memtag_to_string_ftype) (struct gdbarch *gdbarch, struct value *address, enum memtag_type tag_type);
+extern std::string gdbarch_memtag_to_string (struct gdbarch *gdbarch, struct value *address, enum memtag_type tag_type);
+extern void set_gdbarch_memtag_to_string (struct gdbarch *gdbarch, gdbarch_memtag_to_string_ftype *memtag_to_string);
+
+/* Return true if ADDRESS contains a tag and false otherwise. */
+
+typedef bool (gdbarch_tagged_address_p_ftype) (struct gdbarch *gdbarch, struct value *address);
+extern bool gdbarch_tagged_address_p (struct gdbarch *gdbarch, struct value *address);
+extern void set_gdbarch_tagged_address_p (struct gdbarch *gdbarch, gdbarch_tagged_address_p_ftype *tagged_address_p);
+
+/* Return true if the tag from ADDRESS does not match the memory tag for that
+   particular address.  Return false otherwise. */
+
+typedef bool (gdbarch_memtag_mismatch_p_ftype) (struct gdbarch *gdbarch, struct value *address);
+extern bool gdbarch_memtag_mismatch_p (struct gdbarch *gdbarch, struct value *address);
+extern void set_gdbarch_memtag_mismatch_p (struct gdbarch *gdbarch, gdbarch_memtag_mismatch_p_ftype *memtag_mismatch_p);
+
+/* Set the tags for the address range [ADDRESS, ADDRESS + LENGTH) to TAGS
+   Return 0 if successful and non-zero otherwise. */
+
+typedef int (gdbarch_set_memtags_ftype) (struct gdbarch *gdbarch, struct value *address, size_t length, const gdb::byte_vector &tags, enum memtag_type tag_type);
+extern int gdbarch_set_memtags (struct gdbarch *gdbarch, struct value *address, size_t length, const gdb::byte_vector &tags, enum memtag_type tag_type);
+extern void set_gdbarch_set_memtags (struct gdbarch *gdbarch, gdbarch_set_memtags_ftype *set_memtags);
+
+/* Return the tag portion of ADDRESS, assuming ADDRESS is tagged. */
+
+typedef struct value * (gdbarch_get_memtag_ftype) (struct gdbarch *gdbarch, struct value *address, enum memtag_type tag_type);
+extern struct value * gdbarch_get_memtag (struct gdbarch *gdbarch, struct value *address, enum memtag_type tag_type);
+extern void set_gdbarch_get_memtag (struct gdbarch *gdbarch, gdbarch_get_memtag_ftype *get_memtag);
+
+/* memtag_granule_size is the size of the allocation tag granule, for
+   architectures that support memory tagging.
+   This is 0 for architectures that do not support memory tagging.
+   For a non-zero value, this represents the number of bytes of memory per tag. */
+
+extern CORE_ADDR gdbarch_memtag_granule_size (struct gdbarch *gdbarch);
+extern void set_gdbarch_memtag_granule_size (struct gdbarch *gdbarch, CORE_ADDR memtag_granule_size);
+
 /* FIXME/cagney/2001-01-18: This should be split in two.  A target method that
   indicates if the target needs software single step.  An ISA method to
   implement it.
--- a/gdb/gdbarch.sh
+++ b/gdb/gdbarch.sh
@@ -604,6 +604,30 @@ m;CORE_ADDR;addr_bits_remove;CORE_ADDR addr;addr;;core_addr_identity;;0
 # additional data associated with the address.
 v;int;significant_addr_bit;;;;;;0

+# Return a string representation of the memory tag TYPE of ADDRESS.
+# If no tag is associated with such an address, return the empty string.
+m;std::string;memtag_to_string;struct value *address, enum memtag_type tag_type;address, tag_type;;default_memtag_to_string;;0
+
+# Return true if ADDRESS contains a tag and false otherwise.
+m;bool;tagged_address_p;struct value *address;address;;default_tagged_address_p;;0
+
+# Return true if the tag from ADDRESS does not match the memory tag for that
+# particular address.  Return false otherwise.
+m;bool;memtag_mismatch_p;struct value *address;address;;default_memtag_mismatch_p;;0
+
+# Set the tags for the address range [ADDRESS, ADDRESS + LENGTH) to TAGS
+# Return 0 if successful and non-zero otherwise.
+m;int;set_memtags;struct value *address, size_t length, const gdb::byte_vector \&tags, enum memtag_type tag_type;address, length, tags, tag_type;;default_set_memtags;;0
+
+# Return the tag portion of ADDRESS, assuming ADDRESS is tagged.
+m;struct value *;get_memtag;struct value *address, enum memtag_type tag_type;address, tag_type;;default_get_memtag;;0
+
+# memtag_granule_size is the size of the allocation tag granule, for
+# architectures that support memory tagging.
+# This is 0 for architectures that do not support memory tagging.
+# For a non-zero value, this represents the number of bytes of memory per tag.
+v;CORE_ADDR;memtag_granule_size;;;;;;0
+
 # FIXME/cagney/2001-01-18: This should be split in two.  A target method that
 # indicates if the target needs software single step.  An ISA method to
 # implement it.
@@ -1355,6 +1379,18 @@ enum function_call_return_method
  return_method_struct,
 };

+enum memtag_type
+{
+  /* Logical tag, the tag that is stored in unused bits of a pointer to a
+     virtual address.  */
+  tag_logical = 0,
+
+  /* Allocation tag, the tag that is associated with every granule of memory in
+     the physical address space.  Allocation tags are used to validate memory
+     accesses via pointers containing logical tags.  */
+  tag_allocation,
+};
+
 EOF

 # function typedef's