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authorVladimir Murzin <vladimir.murzin@arm.com>2019-02-20 11:43:05 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-03-23 08:44:34 +0100
commitaa5740d660ac628b300af200e6a36c094b25fffa (patch)
treea5d4d62f6dba8cd5cbe33f7a727a12a49c489563
parentc8380f42e82ea2bde5208ba0477ce79db0006d2b (diff)
arm64: Relax GIC version check during early boot
[ Upstream commit 74698f6971f25d045301139413578865fc2bd8f9 ] Updates to the GIC architecture allow ID_AA64PFR0_EL1.GIC to have values other than 0 or 1. At the moment, Linux is quite strict in the way it handles this field at early boot stage (cpufeature is fine) and will refuse to use the system register CPU interface if it doesn't find the value 1. Fixes: 021f653791ad17e03f98aaa7fb933816ae16f161 ("irqchip: gic-v3: Initial support for GICv3") Reported-by: Chase Conklin <Chase.Conklin@arm.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
-rw-r--r--arch/arm64/kernel/head.S3
1 files changed, 1 insertions, 2 deletions
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 0382eba4bf7b..6299a8a361ee 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -478,8 +478,7 @@ CPU_LE( bic x0, x0, #(3 << 24) ) // Clear the EE and E0E bits for EL1
/* GICv3 system register access */
mrs x0, id_aa64pfr0_el1
ubfx x0, x0, #24, #4
- cmp x0, #1
- b.ne 3f
+ cbz x0, 3f
mrs_s x0, ICC_SRE_EL2
orr x0, x0, #ICC_SRE_EL2_SRE // Set ICC_SRE_EL2.SRE==1