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Explicitly define the CPUID index ranges for Transmeta (0x80860000) and
Centaur/Zhaoxin (0xc0000000).
Without these explicit definitions, their respective CPUID indices would
be skipped during CSV bitfield parsing.
Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20250324142042.29010-16-darwi@linutronix.de
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Next commits will introduce vendor-specific CPUID ranges like Transmeta's
0x8086000 range and Centaur's 0xc0000000.
Initially explicit vendor detection was implemented, but it turned out to
be not strictly necessary. As Dave Hansen noted, even established tools
like cpuid(1) just tries all ranges indices, and see if the CPU responds
back with something sensible.
Do something similar at setup_cpuid_range(). Query the range's index,
and check the maximum range function value returned. If it's within an
expected interval of [range_index, range_index + MAX_RANGE_INDEX_OFFSET],
accept the range as valid and further query its leaves.
Set MAX_RANGE_INDEX_OFFSET to a heuristic of 0xff. That should be
sensible enough since all the ranges covered by x86-cpuid-db XML database
are:
0x00000000 0x00000023
0x40000000 0x40000000
0x80000000 0x80000026
0x80860000 0x80860007
0xc0000000 0xc0000001
At setup_cpuid_range(), if the range's returned maximum function was not
sane, mark it as invalid by setting its number of leaves, range->nr, to
zero.
Introduce the for_each_valid_cpuid_range() iterator instead of sprinkling
"range->nr != 0" checks throughout the code.
Suggested-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20250324142042.29010-15-darwi@linutronix.de
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Let index_to_cpuid_range() return a CPUID range only if the passed index
is within a CPUID range's maximum supported function on the CPU.
Returning a CPUID range that is invalid on the CPU for the passed index
does not make sense.
This also avoids repeating the "function index is within CPUID range"
checks, both at setup_cpuid_range() and index_to_func().
Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20250324142042.29010-14-darwi@linutronix.de
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Extend the CPUID index mask macro from 0x80000000 to 0xffff0000. This
accommodates the Transmeta (0x80860000) and Centaur (0xc0000000) index
ranges which will be later added.
This also automatically sets CPUID_FUNCTION_MASK to 0x0000ffff, which is
the actual correct value. Use that macro, instead of the 0xffff literal
where appropriate.
Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20250324142042.29010-13-darwi@linutronix.de
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The kcpuid code assumes only two CPUID index ranges, standard (0x0...)
and extended (0x80000000...).
Since additional CPUID index ranges will be added in further commits,
replace the "is_ext" boolean with enumeration-based range classification.
Collect all CPUID ranges in a structured array and introduce helper
macros to iterate over it. Use such helpers throughout the code.
Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20250324142042.29010-12-darwi@linutronix.de
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Use the __cpuid_count() intrinsic, provided by GCC and LLVM, instead of
rolling a manual version. Both of the kernel's minimum required GCC
version (5.1) and LLVM version (13.0.1) supports it, and it is heavily
used across standard Linux user-space tooling.
This also makes the CPUID call sites more readable.
Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20250324142042.29010-11-darwi@linutronix.de
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Since commit e8c07082a810 ("Kbuild: move to -std=gnu11") and the kernel
allows C99-style variable declarations inside of a for() loop.
Adjust the kcpuid code accordingly.
Note, this helps readability as some of the kcpuid functions have a huge
list of variable declarations on top.
Note, remove the empty lines before cpuid() invocations as it is clearer
to have their parameter initialization and the actual call in one block.
Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20250324142042.29010-10-darwi@linutronix.de
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parse_line() returns an integer but its caller ignored it. Change the
function signature to return void.
While at it, adjust some of the "Skip line" comments for readability.
Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20250324142042.29010-9-darwi@linutronix.de
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The global variable "is_amd" is written to, but is not read from
anywhere. Remove it.
Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20250324142042.29010-8-darwi@linutronix.de
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The local variable "index" is written to, but is not read from
anywhere. Remove it.
Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20250324142042.29010-7-darwi@linutronix.de
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kcpuid --all --detail claims that all bits belong to ECX, in the form
of the header CPUID_${leaf}_ECX[${subleaf}].
Print the correct register name for all CPUID output.
kcpuid --detail also dumps the raw register value if a leaf/subleaf is
covered in the CSV file, but a certain output register within it is not
covered by any CSV entry. Since register names are now properly printed,
and since the CSV file has become exhaustive using x86-cpuid-db, remove
that value dump as it pollutes the output.
While at it, rename decode_bits() to show_reg(). This makes it match its
show_range(), show_leaf() and show_reg_header() counterparts.
Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20250324142042.29010-6-darwi@linutronix.de
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For each CPUID leaf/subleaf query, save the output in an output[] array
instead of spelling it out using EAX to EDX variables.
This allows the CPUID output to be accessed programmatically instead of
calling decode_bits() four times. Loop-based access also allows "kcpuid
--detail" to print the correct output register names in next commit.
Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20250324142042.29010-5-darwi@linutronix.de
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Refactor usage() to accept an exit code parameter and exit the program
after usage output. This streamlines its callers' code paths.
Remove the "Invalid option" error message since getopt_long(3) already
emits a similar message by default.
Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20250324142042.29010-4-darwi@linutronix.de
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If the user passed an invalid CPUID index value through --leaf=index,
kcpuid prints a warning, does nothing, then exits successfully.
Transform the warning to an error, and exit the program with a proper
error code.
Similarly, if the user passed an invalid subleaf, kcpuid prints a
warning, dumps the whole leaf, then exits successfully. Print a clear
error message regarding the invalid subleaf and exit the program with the
proper error code.
Note, moving the "Invalid input index" message from index_to_func() to
show_info() localizes error message handling to the latter, where it
should be. It also allows index_to_func() to be refactored at further
commits.
Note, since after this commit and its parent kcpuid does not just "move
on" on failures, remove the NULL parameter check plus silent exit at
show_func() and show_leaf().
Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20250324142042.29010-3-darwi@linutronix.de
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Error handling in kcpuid is unreliable. On malloc() failures, the code
prints an error then just goes on. The error messages are also printed
to standard output instead of standard error.
Use err() and errx() from <err.h> to direct all error messages to
standard error and automatically exit the program. Use err() to include
the errno information, and errx() otherwise. Use warnx() for warnings.
While at it, alphabetically reorder the header includes.
[ mingo: Fix capitalization in the help text while at it. ]
Fixes: c6b2f240bf8d ("tools/x86: Add a kcpuid tool to show raw CPU features")
Reported-by: Remington Brasga <rbrasga@uci.edu>
Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20250324142042.29010-2-darwi@linutronix.de
Closes: https://lkml.kernel.org/r/20240926223557.2048-1-rbrasga@uci.edu
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It's a common pattern in cpuid leaves to have the same bitfields format
repeated across a number of subleaves. Typically, this is used for
enumerating hierarchial structures like cache and TLB levels, CPU
topology levels, etc.
Modify kcpuid.c to handle subleaf ranges in the CSV file subleaves
column. For example, make it able to parse lines in the form:
# LEAF, SUBLEAVES, reg, bits, short_name , ...
0xb, 1:0, eax, 4:0, x2apic_id_shift , ...
0xb, 1:0, ebx, 15:0, domain_lcpus_count , ...
0xb, 1:0, ecx, 7:0, domain_nr , ...
This way, full output can be printed to the user.
Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20240718134755.378115-8-darwi@linutronix.de
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cpuid.csv will be extended in further commits with all-publicly-known
CPUID leaves and bitfields. Thus, modify has_subleafs() to identify all
known leaves with subleaves.
Remove the redundant "is_amd" check since all x86 vendors already report
the maxium supported extended leaf at leaf 0x80000000 EAX register.
The extra mentioned leaves are:
- Leaf 0x12, Intel Software Guard Extensions (SGX) enumeration
- Leaf 0x14, Intel process trace (PT) enumeration
- Leaf 0x17, Intel SoC vendor attributes enumeration
- Leaf 0x1b, Intel PCONFIG (Platform configuration) enumeration
- Leaf 0x1d, Intel AMX (Advanced Matrix Extensions) tile information
- Leaf 0x1f, Intel v2 extended topology enumeration
- Leaf 0x23, Intel ArchPerfmonExt (Architectural PMU ext) enumeration
- Leaf 0x80000020, AMD Platform QoS extended features enumeration
- Leaf 0x80000026, AMD v2 extended topology enumeration
Set the 'max_subleaf' variable for all the newly marked leaves with extra
subleaves. Ideally, this should be fetched from the CSV file instead,
but the current kcpuid code architecture has two runs: one run to
serially invoke the cpuid instructions and save all the output in-memory,
and one run to parse this in-memory output through the CSV specification.
Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20240718134755.378115-7-darwi@linutronix.de
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While parsing and saving bitfield names from the CSV file, an extra
leading space is copied verbatim. That extra space is not a big issue
now, but further commits will add a new CSV file with much more padding
for the bitfield's name column.
Strip leading/trailing whitespaces while saving bitfield names.
Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20240718134755.378115-6-darwi@linutronix.de
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Protect against the kcpuid code parsing faulty max subleaf numbers
through a min() expression. Thus, ensuring that max_subleaf will always
be ≤ MAX_SUBLEAF_NUM.
Use "u32" for the subleaf numbers since kcpuid is compiled with -Wextra,
which includes signed/unsigned comparisons warnings.
Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20240718134755.378115-5-darwi@linutronix.de
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cpuid.csv will be extended in further commits with all-publicly-known
CPUID leaves and bitfields. One of the new leaves is 0xd for extended
CPU state enumeration. Depending on XCR0 dword bits, it can export up to
64 subleaves.
Set kcpuid.c MAX_SUBLEAF_NUM to 64.
Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20240718134755.378115-4-darwi@linutronix.de
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When kcpuid is invoked with "--all --details", the detailed description
column is not properly aligned for all bitfield rows:
CPUID_0x4_ECX[0x0]:
cache_level : 0x1 - Cache Level ...
cache_self_init - Cache Self Initialization
This is due to differences in output handling between boolean single-bit
"bitflags" and multi-bit bitfields. For the former, the bitfield's value
is not outputted as it is implied to be true by just outputting the
bitflag's name in its respective line.
If long descriptions were requested through the --all parameter, properly
align the bitflag's description columns through extra tabs. With that,
the sample output above becomes:
CPUID_0x4_ECX[0x0]:
cache_level : 0x1 - Cache Level ...
cache_self_init - Cache Self Initialization
Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20240718134755.378115-3-darwi@linutronix.de
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Global variable "num_leafs" is set in multiple places but is never read
anywhere. Remove it.
Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20240718134755.378115-2-darwi@linutronix.de
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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
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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
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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
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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
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