From: Ard Biesheuvel <ardb@kernel.org>
To: linux-arm-kernel@lists.infradead.org, linux@armlinux.org.uk
Cc: arnd@arndb.de, linus.walleij@linaro.org,
Ard Biesheuvel <ardb@kernel.org>
Subject: [PATCH 2/6] ARM: spectre-bhb: fix loop8 sequence for Thumb2
Date: Mon, 28 Mar 2022 15:47:10 +0200 [thread overview]
Message-ID: <20220328134714.205342-3-ardb@kernel.org> (raw)
In-Reply-To: <20220328134714.205342-1-ardb@kernel.org>
In Thumb2, 'b . + 4' produces a branch instruction that uses a narrow
encoding, and so it does not jump to the following instruction as
expected. So use W(b) instead.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
arch/arm/kernel/entry-armv.S | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index ee3f7a599181..4bbd92d41031 100644
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -1040,7 +1040,7 @@ vector_bhb_loop8_\name:
@ bhb workaround
mov r0, #8
-3: b . + 4
+3: W(b) . + 4
subs r0, r0, #1
bne 3b
dsb
--
2.30.2
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next prev parent reply other threads:[~2022-03-28 13:52 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-28 13:47 [PATCH 0/6] ARM: spectre-bhb fixes and tweaks Ard Biesheuvel
2022-03-28 13:47 ` [PATCH 1/6] ARM: spectre-bhb: enable for Cortex-A15 Ard Biesheuvel
2022-05-24 14:50 ` Jon Hunter
2022-05-24 15:21 ` Ard Biesheuvel
2022-05-24 16:06 ` Jon Hunter
2022-05-24 17:03 ` Russell King (Oracle)
2022-05-24 17:49 ` Jon Hunter
2022-05-25 7:09 ` Ard Biesheuvel
2022-05-25 10:48 ` Jon Hunter
2022-05-25 10:52 ` Ard Biesheuvel
2022-06-07 14:30 ` Jon Hunter
2022-06-07 14:32 ` Ard Biesheuvel
2022-06-07 14:35 ` Jon Hunter
2022-06-07 14:39 ` Ard Biesheuvel
2022-03-28 13:47 ` Ard Biesheuvel [this message]
2022-03-28 13:47 ` [PATCH 3/6] ARM: spectre-bhb: simplify BPIALL vector macro Ard Biesheuvel
2022-03-28 13:47 ` [PATCH 4/6] ARM: spectre-bhb: use local DSB and elide ISB in loop8 sequence Ard Biesheuvel
2022-03-28 13:47 ` [PATCH 5/6] ARM: spectre-bhb: avoid cross-subsection jump using a numbered label Ard Biesheuvel
2022-03-31 14:07 ` Russell King (Oracle)
2022-03-31 16:22 ` Ard Biesheuvel
2022-03-28 13:47 ` [PATCH 6/6] ARM: spectre-bhb: rely on linker to emit cross-section literal loads Ard Biesheuvel
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