[RFC,01/13] binutils: Support for the NT_X86_CPUID core dump note
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Commit Message
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(+)
Comments
Hi John
I am aware this is a RFC series where you are mostly looking for
feedback on the overall direction, but I have an implemenation question
below (feel free to discard as part of the RFC process).t
On Mon, Oct 09, 2023 at 11:36:03AM -0700, John Baldwin wrote:
> 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";
The code above (in elfcore_grok_note) only accept "LINUX", and the
comment in "include/elf/common.h" says "note name must be "LINUX".
Is this something you intend to adjust later when adding full FreeBSD
support?
Best,
Lancelot.
> + 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
>
On 10/16/23 2:23 AM, Lancelot SIX wrote:
> Hi John
>
> I am aware this is a RFC series where you are mostly looking for
> feedback on the overall direction, but I have an implemenation question
> below (feel free to discard as part of the RFC process).t
>
> On Mon, Oct 09, 2023 at 11:36:03AM -0700, John Baldwin wrote:
>> 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(+)
>>
>> @@ -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";
>
> The code above (in elfcore_grok_note) only accept "LINUX", and the
> comment in "include/elf/common.h" says "note name must be "LINUX".
>
> Is this something you intend to adjust later when adding full FreeBSD
> support?
I really just kept that to match what is there for NT_X86_XSTATE, but
this patch already includes FreeBSD support (FreeBSD notes use
elfcore_grok_freebsd_note rather than elfcore_grok_note). I almost
left that comment about the note name out, and probably I should just
do that. (Arguably I should also remove that comment from NT_X86_XSTATE
and possibly some others that both FreeBSD and Linux generate.)
On a related note, abusing elf_osabi to determine the note name is a
bit of a hack. It would be nice if elfcore_write_register_note
accepted the note name as an argument, but I'm not sure how much
that would break (e.g. if that's a public binutils API used by
other things than gdb).
@@ -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
@@ -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)
@@ -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:
@@ -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 */