[RFC 01/13] binutils: Support for the NT_X86_CPUID core dump note

[John Baldwin <jhb@FreeBSD.org>]

This core dump note contains an array of CPUID leaf values.  Each
entry in the array contains six 32-bit integers describing the inputs
to the CPUID instruction (%eax and %ecx) and the outputs of the
instruction (%eax, %ebx, %ecx, and %edx) similar to the C structure:

struct cpuid_leaf
{
    uint32_t leaf;
    uint32_t subleaf;
    uint32_t eax;
    uint32_t ebx;
    uint32_t ecx;
    uint32_t edx;
};

Current implementations of this note contain leaves associated with
the XSAVE state area (major leaf 0xd), but future implementations may
add other leaf values in the future.
---
 bfd/elf-bfd.h        |  2 ++
 bfd/elf.c            | 35 +++++++++++++++++++++++++++++++++++
 binutils/readelf.c   |  2 ++
 include/elf/common.h |  2 ++
 4 files changed, 41 insertions(+)

diff --git a/bfd/elf-bfd.h b/bfd/elf-bfd.h
index 335081ec629..235d0931ab4 100644
--- a/bfd/elf-bfd.h
+++ b/bfd/elf-bfd.h
@@ -2871,6 +2871,8 @@ extern char *elfcore_write_prxfpreg
   (bfd *, char *, int *, const void *, int);
 extern char *elfcore_write_xstatereg
   (bfd *, char *, int *, const void *, int);
+extern char *elfcore_write_x86_cpuid
+  (bfd *, char *, int *, const void *, int);
 extern char *elfcore_write_x86_segbases
   (bfd *, char *, int *, const void *, int);
 extern char *elfcore_write_ppc_vmx
diff --git a/bfd/elf.c b/bfd/elf.c
index b5b0c69e097..35679821a49 100644
--- a/bfd/elf.c
+++ b/bfd/elf.c
@@ -10495,6 +10495,16 @@ elfcore_grok_xstatereg (bfd *abfd, Elf_Internal_Note *note)
   return elfcore_make_note_pseudosection (abfd, ".reg-xstate", note);
 }
 
+/* Some systems dump an array of x86 cpuid leaves with a note type of
+   NT_X86_CPUID.  Just include the whole note's contents
+   literally.  */
+
+static bool
+elfcore_grok_x86_cpuid (bfd *abfd, Elf_Internal_Note *note)
+{
+  return elfcore_make_note_pseudosection (abfd, ".reg-x86-cpuid", note);
+}
+
 static bool
 elfcore_grok_ppc_vmx (bfd *abfd, Elf_Internal_Note *note)
 {
@@ -11190,6 +11200,13 @@ elfcore_grok_note (bfd *abfd, Elf_Internal_Note *note)
       else
 	return true;
 
+    case NT_X86_CPUID:
+      if (note->namesz == 6
+	  && strcmp (note->namedata, "LINUX") == 0)
+	return elfcore_grok_x86_cpuid (abfd, note);
+      else
+	return true;
+
     case NT_PPC_VMX:
       if (note->namesz == 6
 	  && strcmp (note->namedata, "LINUX") == 0)
@@ -11768,6 +11785,9 @@ elfcore_grok_freebsd_note (bfd *abfd, Elf_Internal_Note *note)
     case NT_X86_XSTATE:
       return elfcore_grok_xstatereg (abfd, note);
 
+    case NT_X86_CPUID:
+      return elfcore_grok_x86_cpuid (abfd, note);
+
     case NT_FREEBSD_PTLWPINFO:
       return elfcore_make_note_pseudosection (abfd, ".note.freebsdcore.lwpinfo",
 					      note);
@@ -12640,6 +12660,19 @@ elfcore_write_xstatereg (bfd *abfd, char *buf, int *bufsiz,
 			     note_name, NT_X86_XSTATE, xfpregs, size);
 }
 
+char *
+elfcore_write_x86_cpuid (bfd *abfd, char *buf, int *bufsiz,
+			 const void *cpuid, int size)
+{
+  char *note_name;
+  if (get_elf_backend_data (abfd)->elf_osabi == ELFOSABI_FREEBSD)
+    note_name = "FreeBSD";
+  else
+    note_name = "LINUX";
+  return elfcore_write_note (abfd, buf, bufsiz,
+			     note_name, NT_X86_CPUID, cpuid, size);
+}
+
 char *
 elfcore_write_x86_segbases (bfd *abfd, char *buf, int *bufsiz,
 			    const void *regs, int size)
@@ -13233,6 +13266,8 @@ elfcore_write_register_note (bfd *abfd,
     return elfcore_write_prxfpreg (abfd, buf, bufsiz, data, size);
   if (strcmp (section, ".reg-xstate") == 0)
     return elfcore_write_xstatereg (abfd, buf, bufsiz, data, size);
+  if (strcmp (section, ".reg-x86-cpuid") == 0)
+    return elfcore_write_x86_cpuid (abfd, buf, bufsiz, data, size);
   if (strcmp (section, ".reg-x86-segbases") == 0)
     return elfcore_write_x86_segbases (abfd, buf, bufsiz, data, size);
   if (strcmp (section, ".reg-ppc-vmx") == 0)
diff --git a/binutils/readelf.c b/binutils/readelf.c
index c9b6210e229..cb80aa6f396 100644
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -20134,6 +20134,8 @@ get_note_type (Filedata * filedata, unsigned e_type)
 	return _("NT_X86_XSTATE (x86 XSAVE extended state)");
       case NT_X86_CET:
 	return _("NT_X86_CET (x86 CET state)");
+      case NT_X86_CPUID:
+	return _("NT_X86_CPUID (x86 CPUID leaves)");
       case NT_S390_HIGH_GPRS:
 	return _("NT_S390_HIGH_GPRS (s390 upper register halves)");
       case NT_S390_TIMER:
diff --git a/include/elf/common.h b/include/elf/common.h
index 244b13361e5..e8c6d753987 100644
--- a/include/elf/common.h
+++ b/include/elf/common.h
@@ -645,6 +645,8 @@
 					/*   note name must be "LINUX".  */
 #define NT_X86_CET	0x203		/* x86 CET state.  */
 					/*   note name must be "LINUX".  */
+#define NT_X86_CPUID	0x205		/* x86 CPUID leaves.  */
+					/*   note name must be "LINUX".  */
 #define NT_S390_HIGH_GPRS 0x300		/* S/390 upper halves of GPRs  */
 					/*   note name must be "LINUX".  */
 #define NT_S390_TIMER	0x301		/* S390 timer */
-- 
2.41.0