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Message-Id: <20220523165758.790815379@linuxfoundation.org>
Date: Mon, 23 May 2022 19:05:15 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Ard Biesheuvel <ardb@...nel.org>,
"Russell King (Oracle)" <rmk+kernel@...linux.org.uk>,
Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.19 31/44] ARM: 9197/1: spectre-bhb: fix loop8 sequence for Thumb2
From: Ard Biesheuvel <ardb@...nel.org>
[ Upstream commit 3cfb3019979666bdf33a1010147363cf05e0f17b ]
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.
Fixes: 6c7cb60bff7a ("ARM: fix Thumb2 regression with Spectre BHB")
Signed-off-by: Ard Biesheuvel <ardb@...nel.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@...linux.org.uk>
Signed-off-by: Sasha Levin <sashal@...nel.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 a929b6acb149..d779cd1a3b0c 100644
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -1067,7 +1067,7 @@ vector_bhb_loop8_\name:
@ bhb workaround
mov r0, #8
-3: b . + 4
+3: W(b) . + 4
subs r0, r0, #1
bne 3b
dsb
--
2.35.1
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