Messages in this thread Patch in this message | | | Date | Tue, 20 Feb 2018 14:46:24 -0800 | From | Kees Cook <> | Subject | [PATCH] arm64: cpufeature: Trim feature reporting and include PAN emulation |
| |
The PAN emulation notification was only happening for non-boot CPUs if CPU capabilities had already been configured. This seems to be the wrong place, as it's system-wide and isn't attached to capabilities, so its reporting didn't normally happen. Instead, report it once from the boot CPU. Additionally removes the redundant "feature" word from the "CPU features:" line.
Before (redundant "feature", and missing PAN emulation report):
SMP: Total of 4 processors activated. CPU features: detected feature: 32-bit EL0 Support CPU features: detected feature: Kernel page table isolation (KPTI) CPU: All CPU(s) started at EL2
After:
SMP: Total of 4 processors activated. CPU features: detected: 32-bit EL0 Support CPU features: detected: Kernel page table isolation (KPTI) CPU features: emulated: Privileged Access Never (PAN) using TTBR0_EL1 switching CPU: All CPU(s) started at EL2
Signed-off-by: Kees Cook <keescook@chromium.org> --- arch/arm64/kernel/cpufeature.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 29b1f873e337..6c799ca58b53 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -1333,9 +1333,6 @@ static void verify_local_cpu_capabilities(void) if (system_supports_sve()) verify_sve_features(); - - if (system_uses_ttbr0_pan()) - pr_info("Emulating Privileged Access Never (PAN) using TTBR0_EL1 switching\n"); } void check_local_cpu_capabilities(void) @@ -1360,7 +1357,7 @@ void check_local_cpu_capabilities(void) static void __init setup_feature_capabilities(void) { - update_cpu_capabilities(arm64_features, "detected feature:"); + update_cpu_capabilities(arm64_features, "detected:"); enable_cpu_capabilities(arm64_features); } @@ -1394,6 +1391,9 @@ void __init setup_cpu_features(void) if (system_supports_32bit_el0()) setup_elf_hwcaps(compat_elf_hwcaps); + if (system_uses_ttbr0_pan()) + pr_info("emulated: Privileged Access Never (PAN) using TTBR0_EL1 switching\n"); + sve_setup(); /* Advertise that we have computed the system capabilities */ -- 2.7.4
-- Kees Cook Pixel Security
| |