Commit eb92a8ec authored Apr 20, 2022 by Ard Biesheuvel Committed by Greg Kroah-Hartman May 25, 2022

ARM: 9197/1: spectre-bhb: fix loop8 sequence for Thumb2



[ 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@kernel.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 463a7b95

arch/arm/kernel/entry-armv.S

+1 −1

Original line number	Diff line number	Diff line
		@@ -1043,7 +1043,7 @@ vector_bhb_loop8_\name:

		@ bhb workaround
		mov r0, #8
		3: b . + 4
		3: W(b) . + 4
		subs r0, r0, #1
		bne 3b
		dsb