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authorLinus Torvalds <torvalds@linux-foundation.org>2018-08-14 16:39:13 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-08-14 16:39:13 -0700
commit1202f4fdbcb6deeffd3eb39c94b8dc0cc8202b16 (patch)
treeb822d71e82e13846d3a77ffd08b8ef6e571d7d37 /kernel/events
parentd0055f351e647f33f3b0329bff022213bf8aa085 (diff)
parent3c4d9137eefecf273a520d392071ffc9df0a9a7a (diff)
Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 updates from Will Deacon: "A bunch of good stuff in here. Worth noting is that we've pulled in the x86/mm branch from -tip so that we can make use of the core ioremap changes which allow us to put down huge mappings in the vmalloc area without screwing up the TLB. Much of the positive diffstat is because of the rseq selftest for arm64. Summary: - Wire up support for qspinlock, replacing our trusty ticket lock code - Add an IPI to flush_icache_range() to ensure that stale instructions fetched into the pipeline are discarded along with the I-cache lines - Support for the GCC "stackleak" plugin - Support for restartable sequences, plus an arm64 port for the selftest - Kexec/kdump support on systems booting with ACPI - Rewrite of our syscall entry code in C, which allows us to zero the GPRs on entry from userspace - Support for chained PMU counters, allowing 64-bit event counters to be constructed on current CPUs - Ensure scheduler topology information is kept up-to-date with CPU hotplug events - Re-enable support for huge vmalloc/IO mappings now that the core code has the correct hooks to use break-before-make sequences - Miscellaneous, non-critical fixes and cleanups" * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (90 commits) arm64: alternative: Use true and false for boolean values arm64: kexec: Add comment to explain use of __flush_icache_range() arm64: sdei: Mark sdei stack helper functions as static arm64, kaslr: export offset in VMCOREINFO ELF notes arm64: perf: Add cap_user_time aarch64 efi/libstub: Only disable stackleak plugin for arm64 arm64: drop unused kernel_neon_begin_partial() macro arm64: kexec: machine_kexec should call __flush_icache_range arm64: svc: Ensure hardirq tracing is updated before return arm64: mm: Export __sync_icache_dcache() for xen-privcmd drivers/perf: arm-ccn: Use devm_ioremap_resource() to map memory arm64: Add support for STACKLEAK gcc plugin arm64: Add stack information to on_accessible_stack drivers/perf: hisi: update the sccl_id/ccl_id when MT is supported arm64: fix ACPI dependencies rseq/selftests: Add support for arm64 arm64: acpi: fix alignment fault in accessing ACPI efi/arm: map UEFI memory map even w/o runtime services enabled efi/arm: preserve early mapping of UEFI memory map longer for BGRT drivers: acpi: add dependency of EFI for arm64 ...
Diffstat (limited to 'kernel/events')
-rw-r--r--kernel/events/core.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index f6ea33a9f904..80f456ec5d89 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -5246,8 +5246,8 @@ void perf_event_update_userpage(struct perf_event *event)
userpg = rb->user_page;
/*
- * Disable preemption so as to not let the corresponding user-space
- * spin too long if we get preempted.
+ * Disable preemption to guarantee consistent time stamps are stored to
+ * the user page.
*/
preempt_disable();
++userpg->lock;