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Filename Latest commit message Latest commit date
Yang Jihong efdcd77660 arm_pmu: Fix write counter incorrect in ARMv7 big-endian mode
commit fdbef8c4e68ad423416aa6cc93d1616d6f8ac5b3 upstream.

Commit 3a95200d3f ("arm_pmu: Change API to support 64bit counter values")
changes the input "value" type from 32-bit to 64-bit, which introduces the
following problem: ARMv7 PMU counters is 32-bit width, in big-endian mode,
write counter uses high 32-bit, which writes an incorrect value.

Before:

 Performance counter stats for 'ls':

              2.22 msec task-clock                #    0.675 CPUs utilized
                 0      context-switches          #    0.000 K/sec
                 0      cpu-migrations            #    0.000 K/sec
                49      page-faults               #    0.022 M/sec
        2150476593      cycles                    #  966.663 GHz
        2148588788      instructions              #    1.00  insn per cycle
        2147745484      branches                  # 965435.074 M/sec
        2147508540      branch-misses             #   99.99% of all branches

None of the above hw event counters are correct.

Solution:

"value" forcibly converted to 32-bit type before being written to PMU register.

After:

 Performance counter stats for 'ls':

              2.09 msec task-clock                #    0.681 CPUs utilized
                 0      context-switches          #    0.000 K/sec
                 0      cpu-migrations            #    0.000 K/sec
                46      page-faults               #    0.022 M/sec
           2807301      cycles                    #    1.344 GHz
           1060159      instructions              #    0.38  insn per cycle
            250496      branches                  #  119.914 M/sec
             23192      branch-misses             #    9.26% of all branches

Fixes: 3a95200d3f ("arm_pmu: Change API to support 64bit counter values")
Cc: <stable@vger.kernel.org>
Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20210430012659.232110-1-yangjihong1@huawei.com
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-14 16:53:02 +02:00
arch arm_pmu: Fix write counter incorrect in ARMv7 big-endian mode 2021-07-14 16:53:02 +02:00
block blk-mq: Swap two calls in blk_mq_exit_queue() 2021-05-19 10:08:30 +02:00
certs certs: Move load_system_certificate_list to a common function 2021-06-30 08:47:55 -04:00
crypto crypto: rng - fix crypto_rng_reset() refcounting when !CRYPTO_STATS 2021-05-11 14:04:15 +02:00
Documentation mm/slub: clarify verification reporting 2021-06-23 14:41:30 +02:00
drivers Input: joydev - prevent use of not validated data in JSIOCSBTNMAP ioctl 2021-07-14 16:53:02 +02:00
fs ntfs: fix validity check for file name attribute 2021-07-14 16:53:01 +02:00
include certs: Add EFI_CERT_X509_GUID support for dbx entries 2021-06-30 08:47:55 -04:00
init kbuild: add CONFIG_LD_IS_LLD 2021-06-30 08:47:44 -04:00
ipc
kernel mm, futex: fix shared futex pgoff on shmem huge page 2021-06-30 08:47:55 -04:00
lib iov_iter_fault_in_readable() should do nothing in xarray case 2021-07-14 16:53:01 +02:00
LICENSES
mm mm, futex: fix shared futex pgoff on shmem huge page 2021-06-30 08:47:55 -04:00
net net/packet: annotate accesses to po->ifindex 2021-06-30 08:47:48 -04:00
samples samples: vfio-mdev: fix error handing in mdpy_fb_probe() 2021-06-10 13:37:03 +02:00
scripts recordmcount: Correct st_shndx handling 2021-06-30 08:47:49 -04:00
security x86/efi: remove unused variables 2021-07-07 08:22:58 -04:00
sound ALSA: hda/realtek: Apply LED fixup for HP Dragonfly G1, too 2021-07-14 16:52:59 +02:00
tools KVM: selftests: Fix kvm_check_cap() assertion 2021-06-30 08:47:49 -04:00
usr
virt KVM: do not allow mapping valid but non-reference-counted pages 2021-06-30 08:47:50 -04:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile Linux 5.4.131 2021-07-11 12:52:08 +02:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.