From: Reiji Watanabe <reijiw@google.com>
To: Marc Zyngier <maz@kernel.org>
Cc: linux-kernel@vger.kernel.org,
Peter Zijlstra <peterz@infradead.org>,
Mark Rutland <mark.rutland@arm.com>,
Will Deacon <will@kernel.org>
Subject: Re: [PATCH] perf/core: Drop __weak attribute from arch_perf_update_userpage() prototype
Date: Sun, 4 Jun 2023 09:08:10 -0700 [thread overview]
Message-ID: <20230604160810.eu7egpjrcb6ettoh@google.com> (raw)
In-Reply-To: <20230603082519.1088285-1-maz@kernel.org>
On Sat, Jun 03, 2023 at 09:25:19AM +0100, Marc Zyngier wrote:
> 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.
>
> Reported-by: Reiji Watanabe <reijiw@google.com>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: Will Deacon <will@kernel.org>
Tested-by: Reiji Watanabe <reijiw@google.com>
next prev parent reply other threads:[~2023-06-04 16:08 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-03 8:25 Marc Zyngier
2023-06-04 16:08 ` Reiji Watanabe [this message]
2023-06-12 13:16 ` Mark Rutland
2023-06-12 14:16 ` Marc Zyngier
2023-06-12 14:54 ` Peter Zijlstra
2023-06-12 15:03 ` Marc Zyngier
2023-06-16 9:06 ` Peter Zijlstra
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