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arm64: cpufeature: Fix missing ZFR0 in __read_sysreg_by_encoding() 

In commit 06a916feca ("arm64: Expose SVE2 features for
userspace"), new hwcaps are added that are detected via fields in
the SVE-specific ID register ID_AA64ZFR0_EL1.

In order to check compatibility of secondary cpus with the hwcaps
established at boot, the cpufeatures code uses
__read_sysreg_by_encoding() to read this ID register based on the
sys_reg field of the arm64_elf_hwcaps[] table.

This leads to a kernel splat if an hwcap uses an ID register that
__read_sysreg_by_encoding() doesn't explicitly handle, as now
happens when exercising cpu hotplug on an SVE2-capable platform.

So fix it by adding the required case in there.

Fixes: 06a916feca ("arm64: Expose SVE2 features for userspace")
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Dave Martin 2019-06-03 16:35:02 +01:00 committed by Will Deacon
parent 1e29ab3186
commit 78ed70bf3a
1 changed files with 1 additions and 0 deletions
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arch/arm64/kernel/cpufeature.c
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@ -830,6 +830,7 @@ static u64 __read_sysreg_by_encoding(u32 sys_id)
read_sysreg_case(SYS_ID_AA64PFR0_EL1);
read_sysreg_case(SYS_ID_AA64PFR1_EL1);
read_sysreg_case(SYS_ID_AA64ZFR0_EL1);
read_sysreg_case(SYS_ID_AA64DFR0_EL1);
read_sysreg_case(SYS_ID_AA64DFR1_EL1);
read_sysreg_case(SYS_ID_AA64MMFR0_EL1);