aarch64/sme2: Teach binutils/BFD about the NT_ARM_ZT register set

The Scalable Matrix Extension v2 (SME2) defines a new register, ZT0, that
the Linux Kernel handles through a new NT_ARM_ZT register set.

Teach binutils/BFD about it so that gdb can make use of it for reading
and writing core files.  This also enables readelf/objdump to show the
correct identification for the NT_ARM_ZT register set.

Validated under Fast Models.

diff --git a/bfd/elf-bfd.h b/bfd/elf-bfd.h
index 659eef4d150c1e68d3682aabc4511c3fa1807d8a..d9ab5bd16cc2224c6297340be445293e36da9139 100644 (file)
--- a/bfd/elf-bfd.h
+++ b/bfd/elf-bfd.h
@@ -2944,6 +2944,8 @@ extern char *elfcore_write_aarch_ssve
   (bfd *, char *, int *, const void *, int);
 extern char *elfcore_write_aarch_za
   (bfd *, char *, int *, const void *, int);
+extern char *elfcore_write_aarch_zt
+  (bfd *, char *, int *, const void *, int);
 extern char *elfcore_write_arc_v2
   (bfd *, char *, int *, const void *, int);
 extern char *elfcore_write_riscv_csr

diff --git a/bfd/elf.c b/bfd/elf.c
index 33cc39875f9b2dfb04995461791d195ebea7be90..d7109f14039509d4e87e596877aae93063b20f6c 100644 (file)
--- a/bfd/elf.c
+++ b/bfd/elf.c
@@ -10691,6 +10691,15 @@ elfcore_grok_aarch_za (bfd *abfd, Elf_Internal_Note *note)
   return elfcore_make_note_pseudosection (abfd, ".reg-aarch-za", note);
 }
 
+/* Convert NOTE into a bfd_section called ".reg-aarch-zt".  Return TRUE if
+   successful, otherwise return FALSE.  */
+
+static bool
+elfcore_grok_aarch_zt (bfd *abfd, Elf_Internal_Note *note)
+{
+  return elfcore_make_note_pseudosection (abfd, ".reg-aarch-zt", note);
+}
+
 static bool
 elfcore_grok_arc_v2 (bfd *abfd, Elf_Internal_Note *note)
 {
@@ -11420,6 +11429,13 @@ elfcore_grok_note (bfd *abfd, Elf_Internal_Note *note)
       else
        return true;
 
+    case NT_ARM_ZT:
+      if (note->namesz == 6
+         && strcmp (note->namedata, "LINUX") == 0)
+       return elfcore_grok_aarch_zt (abfd, note);
+      else
+       return true;
+
     case NT_GDB_TDESC:
       if (note->namesz == 4
          && strcmp (note->namedata, "GDB") == 0)
@@ -13062,6 +13078,25 @@ elfcore_write_aarch_za (bfd *abfd,
                             size);
 }
 
+/* Write the buffer of zt register values in aarch_zt (length SIZE) into
+   the note buffer BUF and update *BUFSIZ.  ABFD is the bfd the note is being
+   written into.  Return a pointer to the new start of the note buffer, to
+   replace BUF which may no longer be valid.  */
+
+char *
+elfcore_write_aarch_zt (bfd *abfd,
+                       char *buf,
+                       int *bufsiz,
+                       const void *aarch_zt,
+                       int size)
+{
+  char *note_name = "LINUX";
+  return elfcore_write_note (abfd, buf, bufsiz,
+                            note_name, NT_ARM_ZT,
+                            aarch_zt,
+                            size);
+}
+
 char *
 elfcore_write_arc_v2 (bfd *abfd,
                      char *buf,
@@ -13247,6 +13282,8 @@ elfcore_write_register_note (bfd *abfd,
     return elfcore_write_aarch_ssve (abfd, buf, bufsiz, data, size);
   if (strcmp (section, ".reg-aarch-za") == 0)
     return elfcore_write_aarch_za (abfd, buf, bufsiz, data, size);
+  if (strcmp (section, ".reg-aarch-zt") == 0)
+    return elfcore_write_aarch_zt (abfd, buf, bufsiz, data, size);
   if (strcmp (section, ".reg-arc-v2") == 0)
     return elfcore_write_arc_v2 (abfd, buf, bufsiz, data, size);
   if (strcmp (section, ".gdb-tdesc") == 0)

diff --git a/binutils/readelf.c b/binutils/readelf.c
index a06ec79db77e4cf44340f3104cbc0a6eda0a8bc8..a05c75fc1c8e1ae7b49236e10ddbf16c626c51d9 100644 (file)
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -20039,6 +20039,8 @@ get_note_type (Filedata * filedata, unsigned e_type)
        return _("NT_ARM_SSVE (AArch64 streaming SVE registers)");
       case NT_ARM_ZA:
        return _("NT_ARM_ZA (AArch64 SME ZA register)");
+      case NT_ARM_ZT:
+       return _("NT_ARM_ZT (AArch64 SME2 ZT registers)");
       case NT_ARM_PAC_ENABLED_KEYS:
        return _("NT_ARM_PAC_ENABLED_KEYS (AArch64 pointer authentication enabled keys)");
       case NT_ARC_V2:

diff --git a/include/elf/common.h b/include/elf/common.h
index ffa6b60bd2bfe9cc3e78a1506b95e7ce800cd78a..932ea94e3aed53bbe5c1272cf0b90be1e5515502 100644 (file)
--- a/include/elf/common.h
+++ b/include/elf/common.h
@@ -701,6 +701,8 @@
                                        /*   Note: name must be "LINUX".  */
 #define NT_ARM_ZA       0x40c           /* AArch64 SME ZA register.  */
                                        /*   Note: name must be "LINUX".  */
+#define NT_ARM_ZT       0x40d           /* AArch64 SME2 ZT registers.  */
+                                       /*   Note: name must be "LINUX".  */
 #define NT_ARC_V2      0x600           /* ARC HS accumulator/extra registers.  */
                                        /*   note name must be "LINUX".  */
 #define NT_LARCH_CPUCFG 0xa00          /* LoongArch CPU config registers */