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From: Andrew Murray <andrew.murray@arm.com>
To: Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Ard.Biesheuvel@arm.com
Cc: Mark Rutland <mark.rutland@arm.com>,
	Boqun Feng <boqun.feng@gmail.com>,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 1/5] jump_label: Don't warn on __exit jump entries
Date: Wed, 31 Jul 2019 17:12:52 +0100	[thread overview]
Message-ID: <20190731161256.22210-2-andrew.murray@arm.com> (raw)
In-Reply-To: <20190731161256.22210-1-andrew.murray@arm.com>

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In addition to fixing this, we also remove an out-of-date comment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));
 		return false;
 	}
 
-- 
2.21.0


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  reply	other threads:[~2019-07-31 16:13 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 ` Andrew Murray [this message]
2019-07-31 16:41   ` [PATCH v2 1/5] jump_label: Don't warn on __exit jump entries Peter Zijlstra
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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