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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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  parent reply	other threads:[~2022-03-28 13:52 UTC|newest]

Thread overview: 33+ 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 14:50     ` Jon Hunter
2022-05-24 15:21     ` Ard Biesheuvel
2022-05-24 15:21       ` Ard Biesheuvel
2022-05-24 16:06       ` Jon Hunter
2022-05-24 16:06         ` Jon Hunter
2022-05-24 17:03     ` Russell King (Oracle)
2022-05-24 17:03       ` Russell King (Oracle)
2022-05-24 17:49       ` Jon Hunter
2022-05-24 17:49         ` Jon Hunter
2022-05-25  7:09         ` Ard Biesheuvel
2022-05-25  7:09           ` Ard Biesheuvel
2022-05-25 10:48           ` Jon Hunter
2022-05-25 10:48             ` Jon Hunter
2022-05-25 10:52             ` Ard Biesheuvel
2022-05-25 10:52               ` Ard Biesheuvel
2022-06-07 14:30       ` Jon Hunter
2022-06-07 14:30         ` Jon Hunter
2022-06-07 14:32         ` Ard Biesheuvel
2022-06-07 14:32           ` Ard Biesheuvel
2022-06-07 14:35           ` Jon Hunter
2022-06-07 14:35             ` Jon Hunter
2022-06-07 14:39             ` Ard Biesheuvel
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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