| Message ID | 20180827143310.641-3-ykaukab@suse.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | arm64: add support for generic cpu vulnerabilities | expand |
On Mon, Aug 27, 2018 at 04:33:06PM +0200, Mian Yousaf Kaukab wrote: > Checking CSV3 support directly in case CONFIG_UNMAP_KERNEL_AT_EL0 > is not enabled. > > Signed-off-by: Mian Yousaf Kaukab <ykaukab@suse.de> > --- > arch/arm64/kernel/cpu_errata.c | 24 ++++++++++++++++++++++++ > 1 file changed, 24 insertions(+) > > diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c > index dec10898d688..996edb4e18ad 100644 > --- a/arch/arm64/kernel/cpu_errata.c > +++ b/arch/arm64/kernel/cpu_errata.c > @@ -22,6 +22,7 @@ > #include <asm/cpu.h> > #include <asm/cputype.h> > #include <asm/cpufeature.h> > +#include <asm/mmu.h> > > static bool __maybe_unused > is_affected_midr_range(const struct arm64_cpu_capabilities *entry, int scope) > @@ -683,3 +684,26 @@ const struct arm64_cpu_capabilities arm64_errata[] = { > { > } > }; > + > +#ifdef CONFIG_GENERIC_CPU_VULNERABILITIES > + > +ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, > + char *buf) > +{ > + u64 pfr0; > + u32 csv3; > + > + if (arm64_kernel_unmapped_at_el0()) > + return sprintf(buf, "Mitigation: KPTI\n"); > + > + pfr0 = read_cpuid(ID_AA64PFR0_EL1); > + csv3 = cpuid_feature_extract_unsigned_field(pfr0, > + ID_AA64PFR0_CSV3_SHIFT); > + > + if (csv3 || is_cpu_meltdown_safe()) > + return sprintf(buf, "Not affected\n"); > + > + return sprintf(buf, "Vulnerable\n"); This should say something like "Unknown", since we don't actually have a reliable way to determine that a CPU is vulnerable. That's also a large part of the reason why we haven't bothered implementing the sysfs interface so far. Will
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c index dec10898d688..996edb4e18ad 100644 --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -22,6 +22,7 @@ #include <asm/cpu.h> #include <asm/cputype.h> #include <asm/cpufeature.h> +#include <asm/mmu.h> static bool __maybe_unused is_affected_midr_range(const struct arm64_cpu_capabilities *entry, int scope) @@ -683,3 +684,26 @@ const struct arm64_cpu_capabilities arm64_errata[] = { { } }; + +#ifdef CONFIG_GENERIC_CPU_VULNERABILITIES + +ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, + char *buf) +{ + u64 pfr0; + u32 csv3; + + if (arm64_kernel_unmapped_at_el0()) + return sprintf(buf, "Mitigation: KPTI\n"); + + pfr0 = read_cpuid(ID_AA64PFR0_EL1); + csv3 = cpuid_feature_extract_unsigned_field(pfr0, + ID_AA64PFR0_CSV3_SHIFT); + + if (csv3 || is_cpu_meltdown_safe()) + return sprintf(buf, "Not affected\n"); + + return sprintf(buf, "Vulnerable\n"); +} + +#endif
Checking CSV3 support directly in case CONFIG_UNMAP_KERNEL_AT_EL0 is not enabled. Signed-off-by: Mian Yousaf Kaukab <ykaukab@suse.de> --- arch/arm64/kernel/cpu_errata.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+)