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Marc Zyngier dafc70ae6b drivers/perf: apple_m1: Force 63bit counters for M2 CPUs
[ Upstream commit 8be3593b9e ]

Sidharth reports that on M2, the PMU never generates any interrupt
when using 'perf record', which is a annoying as you get no sample.
I'm temped to say "no sample, no problem", but others may have
a different opinion.

Upon investigation, it appears that the counters on M2 are
significantly different from the ones on M1, as they count on
64 bits instead of 48. Which of course, in the fine M1 tradition,
means that we can only use 63 bits, as the top bit is used to signal
the interrupt...

This results in having to introduce yet another flag to indicate yet
another odd counter width. Who knows what the next crazy implementation
will do...

With this, perf can work out the correct offset, and 'perf record'
works as intended.

Tested on M2 and M2-Pro CPUs.

Cc: Janne Grunau <j@jannau.net>
Cc: Hector Martin <marcan@marcan.st>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will@kernel.org>
Fixes: 7d0bfb7c99 ("drivers/perf: apple_m1: Add Apple M2 support")
Reported-by: Sidharth Kshatriya <sid.kshatriya@gmail.com>
Tested-by: Sidharth Kshatriya <sid.kshatriya@gmail.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230528080205.288446-1-maz@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2023-07-19 16:35:14 +02:00
arch x86/sev: Fix calculation of end address based on number of pages 2023-07-19 16:35:08 +02:00
block blk-mq: don't insert passthrough request into sw queue 2023-07-19 16:35:14 +02:00
certs KEYS: Add missing function documentation 2023-04-24 16:15:52 +03:00
crypto KEYS: asymmetric: Copy sig and digest in public_key_verify_signature() 2023-06-02 15:36:23 +02:00
Documentation dt-bindings: iio: ad7192: Add mandatory reference voltage source 2023-07-19 16:35:05 +02:00
drivers drivers/perf: apple_m1: Force 63bit counters for M2 CPUs 2023-07-19 16:35:14 +02:00
fs btrfs: fix file_offset for REQ_BTRFS_ONE_ORDERED bios that get split 2023-07-19 16:35:13 +02:00
include drivers/perf: apple_m1: Force 63bit counters for M2 CPUs 2023-07-19 16:35:14 +02:00
init start_kernel: Add __no_stack_protector function attribute 2023-07-19 16:35:05 +02:00
io_uring io_uring/net: use the correct msghdr union member in io_sendmsg_copy_hdr 2023-06-21 07:34:17 -06:00
ipc Merge branch 'work.namespace' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2023-02-24 19:20:07 -08:00
kernel tick/rcu: Fix bogus ratelimit condition 2023-07-19 16:35:12 +02:00
lib maple_tree: fix potential out-of-bounds access in mas_wr_end_piv() 2023-07-01 13:12:38 +02:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm splice: Fix filemap_splice_read() to use the correct inode 2023-07-19 16:35:07 +02:00
net svcrdma: Prevent page release when nothing was received 2023-07-19 16:35:11 +02:00
rust Rust changes for v6.4 2023-04-30 11:20:22 -07:00
samples samples/bpf: Drop unnecessary fallthrough 2023-05-16 19:44:05 +02:00
scripts scripts/tags.sh: Resolve gtags empty index generation 2023-07-05 18:30:30 +01:00
security selinux: don't use make's grouped targets feature yet 2023-06-01 13:56:13 -04:00
sound ASoC: Fix for v6.4 2023-06-21 15:23:23 +02:00
tools Revert "cxl/port: Enable the HDM decoder capability for switch ports" 2023-07-05 18:30:30 +01:00
usr initramfs: Check negative timestamp to prevent broken cpio archive 2023-04-16 17:37:01 +09:00
virt KVM: Avoid illegal stage2 mapping on invalid memory slot 2023-06-22 15:14:57 -04:00
.clang-format cxl for v6.4 2023-04-30 11:51:51 -07:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for *.dtso files 2023-02-26 15:28:23 +09:00
.gitignore linux-kselftest-kunit-6.4-rc1 2023-04-24 12:31:32 -07:00
.mailmap mailmap: add entries for Ben Dooks 2023-06-19 13:19:35 -07:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: sctp: move Neil to CREDITS 2023-05-12 08:51:32 +01:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Networking fixes for 6.4-rc8, including fixes from ipsec, bpf, 2023-06-22 17:59:51 -07:00
Makefile Linux 6.4.3 2023-07-11 06:31:05 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.