From: Dave Martin Date: Mon, 3 Jun 2019 15:35:02 +0000 (+0100) Subject: arm64: cpufeature: Fix missing ZFR0 in __read_sysreg_by_encoding() X-Git-Tag: v5.2-rc4~23^2~4 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=78ed70bf3a923f1965e3c19f544677d418397108;p=linux.git arm64: cpufeature: Fix missing ZFR0 in __read_sysreg_by_encoding() In commit 06a916feca2b ("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: 06a916feca2b ("arm64: Expose SVE2 features for userspace") Signed-off-by: Dave Martin Signed-off-by: Will Deacon --- diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index ca27e08e3d8a..80babf451519 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -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);