tools/x86/kcpuid: Dump the correct CPUID function in error

The tool uses the 16 least significant bits of the CPUID leaf as an
index into its array of CPUID function field descriptions.

However, when that index is non-existent, it uses the same, truncated
index to report it, which is wrong:

$ kcpuid -l 0x80000034
ERR: invalid input index (0x34)

Use the original index number in the error message.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230426094107.27348-1-bp@alien8.de

tools/x86/kcpuid: Dump the CPUID function in detailed view

Sometimes it is useful to know which CPUID leaf contains the fields so
add it to -d output so that it looks like this:

CPUID_0x8000001e_ECX[0x0]:
extended_apic_id : 0x8 - Extended APIC ID
core_id : 0x4 - Identifies the logical core ID
threads_per_core : 0x1 - The number of threads per core is threads_per_core + 1
node_id : 0x0 - Node ID
nodes_per_processor : 0x0 - Nodes per processor { 0: 1 node, else reserved }

CPUID_0x8000001f_ECX[0x0]:
sme - Secure Memory Encryption

...

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Terry Bowman <terry.bowman@amd.com>
Reviewed-by: Feng Tang <feng.tang@intel.com>
Link: https://lore.kernel.org/r/20230206141832.4162264-4-terry.bowman@amd.com

tools/x86/kcpuid: Check last token too

Input lines like

0x8000001E, 0, EAX, 31:0, Extended APIC ID

where the short name is missing lead to a segfault because the loop
takes the long name for the short name and tokens[5] becomes NULL which
explodes later in strcpy().

Check its value too before further processing.

Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Feng Tang <feng.tang@intel.com>
Link: https://lkml.kernel.org/r/20210315125901.30315-1-bp@alien8.de

tools/x86: Add a kcpuid tool to show raw CPU features

End users frequently want to know what features their processor
supports, independent of what the kernel supports.

/proc/cpuinfo is great. It is omnipresent and since it is provided by
the kernel it is always as up to date as the kernel. But, it could be
ambiguous about processor features which can be disabled by the kernel
at boot-time or compile-time.

There are some user space tools showing more raw features, but they are
not bound with kernel, and go with distros. Many end users are still
using old distros with new kernels (upgraded by themselves), and may
not upgrade the distros only to get a newer tool.

So here arise the need for a new tool, which
* shows raw CPU features read from the CPUID instruction
* will be easier to update compared to existing userspace
tooling (perhaps distributed like perf)
* inherits "modern" kernel development process, in contrast to some
of the existing userspace CPUID tools which are still being developed
without git and distributed in tarballs from non-https sites.
* Can produce output consistent with /proc/cpuinfo to make comparison
easier.

The CPUID leaf definitions are kept in an .csv file which allows for
updating only that file to add support for new feature leafs.

This is based on prototype code from Borislav Petkov
(http://sr71.net/~dave/intel/stupid-cpuid.c).

[ bp:
- Massage, add #define _GNU_SOURCE to fix implicit declaration of
function ‘strcasestr' warning
- remove superfluous newlines
- fallback to cpuid.csv in the current dir if none found
- fix typos
- move comments over the lines instead of sideways. ]

Originally-from: Borislav Petkov <bp@alien8.de>
Suggested-by: Dave Hansen <dave.hansen@intel.com>
Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/1614928878-86075-1-git-send-email-feng.tang@intel.com