From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x226lYxUCzi40jvNVNn71eO9oVlHc3ZDjMRqUkZJ2H5zuSiP91GAaCe7fdQ+Dfiru5nu6z+m0 ARC-Seal: i=1; a=rsa-sha256; t=1518709214; cv=none; d=google.com; s=arc-20160816; b=aGfBjwMqBoTLWQqFJfUeqkk/pB+KC56CTAozX3h4Di6Baot5SiNGmwTwrxbtO4yDXU 7iy0LmlSY3F+HNCfwHPbypM7hztcaypgMK0195ryVe9jJaFeYRezKC2qGtYmm+Vb4j6k asNv8hg80YeS46yI4ZEW730fjtOxWy+4oFSsVyDTlW88XkUpvCEA1rm/edh0UjmKW3sx 2TyXLTQTeiEr6dvq/sp/2vl/XBqmctMQ6ULQ2ehhDsogKBFGBR+lsoCP0v4TwAnQwFoR 3gnKQiIsBTJunYfN38epyT+girD/0xyG8wJR1kjmeOBvb8iDnQz+8NKOE9T5oD2z/Not yGVg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=4MwcmmNSsyfpuMv98DfigU1FydjePj78c5jOc8I/aVc=; b=I4HV3iHczEgcZfWQqtgbk6q2sROtoKcfDoI9GmmV5OPHYLjUHDcJxr3wMNfqK3DGyp ZAGA8uTzVJW7JYlZPEwjQYYGYu/YMgpYuCPoaq/0kpZ0jsbvYVDfM8gJeRG9EAI1Hb6N LSZYStt298GoQG7rTc4RixGENrStSsFgE0w5+P1kPCOOCKTcAdLIsyQiq3I2EORL5MHd Wwz9kJQTCuFp0UnhZxztBaZrAQzNvuRibjRVNueGctRv+9goLpI5BEgVbpVDh2O24Kls J3AWc/q4BIYHFyZYQY/XCaBTX6Cpy0DVzOLrkjpbsOVc7XwTiAHtGmPLqe4UMMkk/p5L agfA== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.71.90 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.71.90 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Suzuki K Poulose , Will Deacon , Catalin Marinas Subject: [PATCH 4.15 036/202] [Variant 3/Meltdown] arm64: Take into account ID_AA64PFR0_EL1.CSV3 Date: Thu, 15 Feb 2018 16:15:36 +0100 Message-Id: <20180215151714.896334852@linuxfoundation.org> X-Mailer: git-send-email 2.16.1 In-Reply-To: <20180215151712.768794354@linuxfoundation.org> References: <20180215151712.768794354@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1592481486304015991?= X-GMAIL-MSGID: =?utf-8?q?1592482032772141018?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Will Deacon Commit 179a56f6f9fb upstream. For non-KASLR kernels where the KPTI behaviour has not been overridden on the command line we can use ID_AA64PFR0_EL1.CSV3 to determine whether or not we should unmap the kernel whilst running at EL0. Reviewed-by: Suzuki K Poulose Signed-off-by: Will Deacon Signed-off-by: Catalin Marinas Conflicts: arch/arm64/kernel/cpufeature.c Signed-off-by: Greg Kroah-Hartman --- arch/arm64/include/asm/sysreg.h | 1 + arch/arm64/kernel/cpufeature.c | 8 +++++++- 2 files changed, 8 insertions(+), 1 deletion(-) --- a/arch/arm64/include/asm/sysreg.h +++ b/arch/arm64/include/asm/sysreg.h @@ -437,6 +437,7 @@ #define ID_AA64ISAR1_DPB_SHIFT 0 /* id_aa64pfr0 */ +#define ID_AA64PFR0_CSV3_SHIFT 60 #define ID_AA64PFR0_SVE_SHIFT 32 #define ID_AA64PFR0_GIC_SHIFT 24 #define ID_AA64PFR0_ASIMD_SHIFT 20 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -145,6 +145,7 @@ static const struct arm64_ftr_bits ftr_i }; static const struct arm64_ftr_bits ftr_id_aa64pfr0[] = { + ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_CSV3_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SVE), FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_SVE_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_GIC_SHIFT, 4, 0), @@ -852,6 +853,8 @@ static int __kpti_forced; /* 0: not forc static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry, int __unused) { + u64 pfr0 = read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1); + /* Forced on command line? */ if (__kpti_forced) { pr_info_once("kernel page table isolation forced %s by command line option\n", @@ -863,7 +866,9 @@ static bool unmap_kernel_at_el0(const st if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) return true; - return false; + /* Defer to CPU feature registers */ + return !cpuid_feature_extract_unsigned_field(pfr0, + ID_AA64PFR0_CSV3_SHIFT); } static int __init parse_kpti(char *str) @@ -968,6 +973,7 @@ static const struct arm64_cpu_capabiliti }, #ifdef CONFIG_UNMAP_KERNEL_AT_EL0 { + .desc = "Kernel page table isolation (KPTI)", .capability = ARM64_UNMAP_KERNEL_AT_EL0, .def_scope = SCOPE_SYSTEM, .matches = unmap_kernel_at_el0,