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UPSTREAM: perf/core: Drop __weak attribute from arch_perf_update_userpage() prototype

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Reiji reports that the arm64 implementation of arch_perf_update_userpage()
is now ignored and replaced by the dummy stub in core code.
This seems to happen since the PMUv3 driver was moved to driver/perf.

As it turns out, dropping the __weak attribute from the *prototype*
of the function solves the problem. You're right, this doesn't seem
to make much sense. And yet... It appears that both symbols get
flagged as weak, and that the first one to appear in the link order
wins:

$ nm drivers/perf/arm_pmuv3.o|grep arch_perf_update_userpage
0000000000001db0 W arch_perf_update_userpage

Dropping the attribute from the prototype restores the expected
behaviour, and arm64 is able to enjoy arch_perf_update_userpage()
again.

Fixes: 7755cec63a ("arm64: perf: Move PMUv3 driver to drivers/perf")
Fixes: f1ec3a517b ("kernel/events: Add a missing prototype for arch_perf_update_userpage()")
Reported-by: Reiji Watanabe <reijiw@google.com>
Change-Id: I497041999776e66ac77c3fccdd09ce47aae544e9
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Reiji Watanabe <reijiw@google.com>
Link: https://lkml.kernel.org/r/20230616114831.3186980-1-maz@kernel.org
(cherry picked from commit b50f26a448)
Signed-off-by: Danesh Petigara <danesh.petigara@broadcom.com>
This commit is contained in:
Marc Zyngier
2023-06-16 12:48:31 +01:00
committed by Pierre Couillaud
parent bf3022d3c3
commit 6d7eea37f7
1 changed files with 3 additions and 3 deletions
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6
include/linux/perf_event.h
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@@ -1719,9 +1719,9 @@ int perf_event_exit_cpu(unsigned int cpu);
#define perf_event_exit_cpu NULL #define perf_event_exit_cpu NULL
#endif #endif
extern void __weak arch_perf_update_userpage(struct perf_event *event, extern void arch_perf_update_userpage(struct perf_event *event,
struct perf_event_mmap_page *userpg, struct perf_event_mmap_page *userpg,
u64 now); u64 now);
#ifdef CONFIG_MMU #ifdef CONFIG_MMU
extern __weak u64 arch_perf_get_page_size(struct mm_struct *mm, unsigned long addr); extern __weak u64 arch_perf_get_page_size(struct mm_struct *mm, unsigned long addr);