[PATCH 1/2] arm64/sve: Ensure that all fields in ZCR_EL1 are set to known values

[Mark Brown <broonie@kernel.org>]

At present nothing in our CPU initialisation code ever sets unknown fields
in ZCR_EL1 to known values, all updates to ZCR_EL1 are read/modify/write
sequences for LEN. All the unknown fields are RES0, explicitly initialise
them as such to avoid future surprises.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 arch/arm64/kernel/fpsimd.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index a5dc6f764195..cc3c9ad877a8 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -1134,6 +1134,8 @@ void cpu_enable_sve(const struct arm64_cpu_capabilities *__always_unused p)
 {
 	write_sysreg(read_sysreg(CPACR_EL1) | CPACR_EL1_ZEN_EL1EN, CPACR_EL1);
 	isb();
+
+	write_sysreg_s(0, SYS_ZCR_EL1);
 }
 
 void __init sve_setup(void)

-- 
2.30.2