From mboxrd@z Thu Jan 1 00:00:00 1970 From: ykaukab@suse.de (Mian Yousaf Kaukab) Date: Tue, 7 Aug 2018 20:14:14 +0200 Subject: [PATCH 1/6] arm64: kpti: move check for non-vulnerable CPUs to a function In-Reply-To: <20180807181419.15690-1-ykaukab@suse.de> References: <20180807181419.15690-1-ykaukab@suse.de> Message-ID: <20180807181419.15690-2-ykaukab@suse.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Prepare to call it in generic cpu vulnerabilities support. Signed-off-by: Mian Yousaf Kaukab --- arch/arm64/include/asm/cpufeature.h | 16 ++++++++++++++++ arch/arm64/kernel/cpufeature.c | 9 +-------- 2 files changed, 17 insertions(+), 8 deletions(-) diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index 1717ba1db35d..0b0b5b3e36ba 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -530,6 +530,22 @@ void arm64_set_ssbd_mitigation(bool state); static inline void arm64_set_ssbd_mitigation(bool state) {} #endif +static inline bool is_cpu_meltdown_safe(void) +{ + /* List of CPUs that are not vulnerable and don't need KPTI */ + static const struct midr_range kpti_safe_list[] = { + MIDR_ALL_VERSIONS(MIDR_CAVIUM_THUNDERX2), + MIDR_ALL_VERSIONS(MIDR_BRCM_VULCAN), + { /* sentinel */ } + }; + + /* Don't force KPTI for CPUs that are not vulnerable */ + if (is_midr_in_range_list(read_cpuid_id(), kpti_safe_list)) + return true; + + return false; +} + #endif /* __ASSEMBLY__ */ #endif diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index e238b7932096..6a94f8bce35a 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -865,12 +865,6 @@ static int __kpti_forced; /* 0: not forced, >0: forced on, <0: forced off */ static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry, int scope) { - /* List of CPUs that are not vulnerable and don't need KPTI */ - static const struct midr_range kpti_safe_list[] = { - MIDR_ALL_VERSIONS(MIDR_CAVIUM_THUNDERX2), - MIDR_ALL_VERSIONS(MIDR_BRCM_VULCAN), - { /* sentinel */ } - }; char const *str = "command line option"; /* @@ -894,8 +888,7 @@ static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry, if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) return true; - /* Don't force KPTI for CPUs that are not vulnerable */ - if (is_midr_in_range_list(read_cpuid_id(), kpti_safe_list)) + if (is_cpu_meltdown_safe()) return false; /* Defer to CPU feature registers */ -- 2.11.0