From: Vladimir Murzin vladimir.murzin@arm.com
[ Upstream commit 6849b5eba1965ceb0cad3a75877ef4569dd3638e ]
Updates to the Generic Timer architecture allow ID_PFR1.GenTimer to have values other than 0 or 1 while still preserving backward compatibility. At the moment, Linux is quite strict in the way it handles this field at early boot and will not configure arch timer if it doesn't find the value 1.
Since here use ubfx for arch timer version extraction (hyb-stub build with -march=armv7-a, so it is safe)
To help backports (even though the code was correct at the time of writing)
Fixes: 8ec58be9f3ff ("ARM: virt: arch_timers: enable access to physical timers") Acked-by: Marc Zyngier maz@kernel.org Signed-off-by: Vladimir Murzin vladimir.murzin@arm.com Signed-off-by: Russell King rmk+kernel@armlinux.org.uk Signed-off-by: Sasha Levin sashal@kernel.org --- arch/arm/kernel/hyp-stub.S | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S index ae5020302de49..6607fa817bba9 100644 --- a/arch/arm/kernel/hyp-stub.S +++ b/arch/arm/kernel/hyp-stub.S @@ -146,10 +146,9 @@ ARM_BE8(orr r7, r7, #(1 << 25)) @ HSCTLR.EE #if !defined(ZIMAGE) && defined(CONFIG_ARM_ARCH_TIMER) @ make CNTP_* and CNTPCT accessible from PL1 mrc p15, 0, r7, c0, c1, 1 @ ID_PFR1 - lsr r7, #16 - and r7, #0xf - cmp r7, #1 - bne 1f + ubfx r7, r7, #16, #4 + teq r7, #0 + beq 1f mrc p15, 4, r7, c14, c1, 0 @ CNTHCTL orr r7, r7, #3 @ PL1PCEN | PL1PCTEN mcr p15, 4, r7, c14, c1, 0 @ CNTHCTL