Re: perf usage of arch/arm64/include/asm/cputype.h

[Yicong Yang]

+ linux-arm-kernel

On 2025/6/14 4:13, Arnaldo Carvalho de Melo wrote:
> Hi,
> 
> tools/perf (and other tools/ living code) uses a file from the kernel, a
> copy, so that we don't break its build when something changes in the
> kernel that tooling uses.
> 
> There is this tools/perf/check-headers.sh that does the "copy coherency
> check", while trying to act on such a warning I stumbled on the report
> below.
> 
> More details at:
> 
>   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/include/uapi/README
> 
> 
> If you could please take a look at this that would be great, the initial
> copy was made at:
> 
> commit 1314376d495f2d79cc58753ff3034ccc503c43c9
> Author: Ali Saidi <alisaidi@xxxxxxxxxx>
> Date:   Thu Mar 24 18:33:20 2022 +0000
> 
>     tools arm64: Import cputype.h
>     
>     Bring-in the kernel's arch/arm64/include/asm/cputype.h into tools/
>     for arm64 to make use of all the core-type definitions in perf.
>     
>     Replace sysreg.h with the version already imported into tools/.
>     
>     Committer notes:
>     
>     Added an entry to tools/perf/check-headers.sh, so that we get notified
>     when the original file in the kernel sources gets modified.
>     
>     Tester notes:
>     
>     LGTM. I did the testing on both my x86 and Arm64 platforms, thanks for
>     the fixing up.
>     
>     Signed-off-by: Ali Saidi <alisaidi@xxxxxxxxxx>
>     Tested-by: Leo Yan <leo.yan@xxxxxxxxxx>
> 
> - Arnaldo
> 
> ⬢ [acme@toolbx perf-tools]$ m
> rm: cannot remove '/home/acme/libexec/perf-core/scripts/python/Perf-Trace-Util/lib/Perf/Trace/__pycache__/Core.cpython-313.pyc': Permission denied
> make: Entering directory '/home/acme/git/perf-tools/tools/perf'
>   BUILD:   Doing 'make -j32' parallel build
> Warning: Kernel ABI header differences:
>   diff -u tools/arch/x86/include/asm/cpufeatures.h arch/x86/include/asm/cpufeatures.h
>   diff -u tools/arch/arm64/include/asm/cputype.h arch/arm64/include/asm/cputype.h
> 
> Auto-detecting system features:
> ...                                   libdw: [ on  ]
> ...                                   glibc: [ on  ]
> ...                                  libelf: [ on  ]
> ...                                 libnuma: [ on  ]
> ...                  numa_num_possible_cpus: [ on  ]
> ...                                 libperl: [ on  ]
> ...                               libpython: [ on  ]
> ...                               libcrypto: [ on  ]
> ...                             libcapstone: [ on  ]
> ...                               llvm-perf: [ on  ]
> ...                                    zlib: [ on  ]
> ...                                    lzma: [ on  ]
> ...                               get_cpuid: [ on  ]
> ...                                     bpf: [ on  ]
> ...                                  libaio: [ on  ]
> ...                                 libzstd: [ on  ]
> 
>   INSTALL libsubcmd_headers
>   INSTALL libperf_headers
>   INSTALL libapi_headers
>   INSTALL libsymbol_headers
>   INSTALL libbpf_headers
>   INSTALL binaries
>   INSTALL tests
>   INSTALL libperf-jvmti.so
>   INSTALL libexec
>   INSTALL perf-archive
>   INSTALL perf-iostat
>   INSTALL perl-scripts
>   INSTALL python-scripts
>   INSTALL dlfilters
>   INSTALL perf_completion-script
>   INSTALL perf-tip
> make: Leaving directory '/home/acme/git/perf-tools/tools/perf'
>  18: 'import perf' in python                                         : Ok
> ⬢ [acme@toolbx perf-tools]$ cp arch/arm64/include/asm/cputype.h tools/arch/arm64/include/asm/cputype.h
> ⬢ [acme@toolbx perf-tools]$ m
> rm: cannot remove '/home/acme/libexec/perf-core/scripts/python/Perf-Trace-Util/lib/Perf/Trace/__pycache__/Core.cpython-313.pyc': Permission denied
> make: Entering directory '/home/acme/git/perf-tools/tools/perf'
>   BUILD:   Doing 'make -j32' parallel build
> Warning: Kernel ABI header differences:
>   diff -u tools/arch/x86/include/asm/cpufeatures.h arch/x86/include/asm/cpufeatures.h
> 
> Auto-detecting system features:
> ...                                   libdw: [ on  ]
> ...                                   glibc: [ on  ]
> ...                                  libelf: [ on  ]
> ...                                 libnuma: [ on  ]
> ...                  numa_num_possible_cpus: [ on  ]
> ...                                 libperl: [ on  ]
> ...                               libpython: [ on  ]
> ...                               libcrypto: [ on  ]
> ...                             libcapstone: [ on  ]
> ...                               llvm-perf: [ on  ]
> ...                                    zlib: [ on  ]
> ...                                    lzma: [ on  ]
> ...                               get_cpuid: [ on  ]
> ...                                     bpf: [ on  ]
> ...                                  libaio: [ on  ]
> ...                                 libzstd: [ on  ]
> 
>   INSTALL libsubcmd_headers
>   INSTALL libperf_headers
>   INSTALL libapi_headers
>   INSTALL libsymbol_headers
>   INSTALL libbpf_headers
>   CC      /tmp/build/perf-tools/util/arm-spe.o
> util/arm-spe.c: In function ‘arm_spe__synth_ds’:
> util/arm-spe.c:885:43: error: passing argument 1 of ‘is_midr_in_range_list’ makes pointer from integer without a cast [-Wint-conversion]
>   885 |                 if (is_midr_in_range_list(midr, data_source_handles[i].midr_ranges)) {
>       |                                           ^~~~
>       |                                           |
>       |                                           u64 {aka long unsigned int}
> In file included from util/arm-spe.c:37:
> util/../../arch/arm64/include/asm/cputype.h:306:53: note: expected ‘const struct midr_range *’ but argument is of type ‘u64’ {aka ‘long unsigned int’}
>   306 | bool is_midr_in_range_list(struct midr_range const *ranges);
>       |                            ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~
> util/arm-spe.c:885:21: error: too many arguments to function ‘is_midr_in_range_list’; expected 1, have 2
>   885 |                 if (is_midr_in_range_list(midr, data_source_handles[i].midr_ranges)) {
>       |                     ^~~~~~~~~~~~~~~~~~~~~       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> util/../../arch/arm64/include/asm/cputype.h:306:6: note: declared here
>   306 | bool is_midr_in_range_list(struct midr_range const *ranges);
>       |      ^~~~~~~~~~~~~~~~~~~~~
> make[4]: *** [/home/acme/git/perf-tools/tools/build/Makefile.build:85: /tmp/build/perf-tools/util/arm-spe.o] Error 1
> make[3]: *** [/home/acme/git/perf-tools/tools/build/Makefile.build:142: util] Error 2
> make[2]: *** [Makefile.perf:798: /tmp/build/perf-tools/perf-util-in.o] Error 2
> make[1]: *** [Makefile.perf:290: sub-make] Error 2
> make: *** [Makefile:119: install-bin] Error 2
> make: Leaving directory '/home/acme/git/perf-tools/tools/perf'
> ⬢ [acme@toolbx perf-tools]$ 
> 
> 

The changes should be introduced by arm64's errata management on live migration[1], specifically:
- commit e3121298c7fc ("arm64: Modify _midr_range() functions to read MIDR/REVIDR internally")
  which changed the implementation of is_midr_in_range() that the MIDR to
  test is always read on the current CPU. This isn't true in perf since
  the MIDR is acquired from the perf.data.
- commit c8c2647e69be ("arm64: Make  _midr_in_range_list() an exported function")
  which moves the implementation out of the header file.

Below patch should keep the copy coherency of cputype.h to implement the _midr_in_range_list()
as before.

[1] https://lore.kernel.org/all/20250221140229.12588-1-shameerali.kolothum.thodi@xxxxxxxxxx/

Thanks.