From: Peter Zijlstra <peterz@infradead.org>
To: Andrew Murray <andrew.murray@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Boqun Feng <boqun.feng@gmail.com>,
Will Deacon <will.deacon@arm.com>,
Ard.Biesheuvel@arm.com, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 1/5] jump_label: Don't warn on __exit jump entries
Date: Wed, 31 Jul 2019 18:41:56 +0200 [thread overview]
Message-ID: <20190731164156.GX31398@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20190731161256.22210-2-andrew.murray@arm.com>
On Wed, Jul 31, 2019 at 05:12:52PM +0100, Andrew Murray wrote:
> On architectures that discard .exit.* sections at runtime, a
> warning is printed for each jump label that is used within an
> in-kernel __exit annotated function:
>
> can't patch jump_label at ehci_hcd_cleanup+0x8/0x3c
> WARNING: CPU: 0 PID: 1 at kernel/jump_label.c:410 __jump_label_update+0x12c/0x138
>
> As these functions will never get executed (they are free'd along
> with the rest of initmem) - we do not need to patch them and should
> not display any warnings.
>
> The warning is displayed because the test required to satisfy
> jump_entry_is_init is based on init_section_contains (__init_begin to
> __init_end) whereas the test in __jump_label_update is based on
> init_kernel_text (_sinittext to _einittext) via kernel_text_address).
>
> In addition to fixing this, we also remove an out-of-date comment
> and use a WARN instead of a WARN_ONCE.
>
> Fixes: 19483677684b ("jump_label: Annotate entries that operate on __init code earlier")
> Signed-off-by: Andrew Murray <andrew.murray@arm.com>
> ---
> kernel/jump_label.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/jump_label.c b/kernel/jump_label.c
> index df3008419a1d..c984078a5c28 100644
> --- a/kernel/jump_label.c
> +++ b/kernel/jump_label.c
> @@ -407,7 +407,9 @@ static bool jump_label_can_update(struct jump_entry *entry, bool init)
> return false;
>
> if (!kernel_text_address(jump_entry_code(entry))) {
> - WARN_ONCE(1, "can't patch jump_label at %pS", (void *)jump_entry_code(entry));
> + if (!jump_entry_is_init(entry))
> + WARN_ONCE(1, "can't patch jump_label at %pS",
> + (void *)jump_entry_code(entry));
It seems to me we can writes that as:
WARN_ONCE(!jump_entry_is_init(entry),
"can't patch jump_label at %pS",
(void *)jump_entry_code(entry));
> return false;
> }
Other than that,
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
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next prev parent reply other threads:[~2019-07-31 16:42 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-31 16:12 [PATCH v2 0/5] arm64: avoid out-of-line ll/sc atomics Andrew Murray
2019-07-31 16:12 ` [PATCH v2 1/5] jump_label: Don't warn on __exit jump entries Andrew Murray
2019-07-31 16:41 ` Peter Zijlstra [this message]
2019-08-02 8:22 ` Andrew Murray
2019-07-31 16:12 ` [PATCH v2 2/5] arm64: Use correct ll/sc atomic constraints Andrew Murray
2019-07-31 16:12 ` [PATCH v2 3/5] arm64: atomics: avoid out-of-line ll/sc atomics Andrew Murray
2019-08-01 3:10 ` Boqun Feng
2019-08-01 8:12 ` Andrew Murray
2019-07-31 16:12 ` [PATCH v2 4/5] arm64: avoid using hard-coded registers for LSE atomics Andrew Murray
2019-07-31 16:12 ` [PATCH v2 5/5] arm64: atomics: remove atomic_ll_sc compilation unit Andrew Murray
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