From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx4/xKhAcugLP+7euFsTe3lwBEjG4quLg6kFEfk0TycRTO7i0pRoHW6citnWHHtlfVyLmx9o0 ARC-Seal: i=1; a=rsa-sha256; t=1523021769; cv=none; d=google.com; s=arc-20160816; b=LUoBr4Dm+VtEB4O8mCC8NCcwBCxFdy8jOkXRJk/GjpZWd05r9VqJ4/ixsXRB4/fTS0 5DpNlueoq988lGLrsi4Mwi9QvxJLRwsSL2UjVhgBrVJ/DmbsaQAXXefmBDZlXHQS+JHc 80H2H2YvpN6o6Wm/9sG1ympxd5ePR/k1dHqHbME4opHCYthNvH+SGlYzAXZ9LcduMsBZ 33OhKwJOZq7gzTMxVDNUWXdmvOMz08keaz1RlhzyRT4v3CSX4G9oGxb091FA+I/Ly/NT RUCH9tK+gC/j4+MNSTIj2/Uk7HbFDdR4vkLeHxVZxUkNyTPtzef/SJvRJjwUVN17KI2Y MQXg== 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=Pqnl96G2SvEmTKLa0HJaFX0skUSrHtCwmwDfIsqWVBE=; b=PeXlsUX73Bo5r4H6Py9i2e83z0Y4Uy/iUuR6EJKFiTH2nqWd5ILTSrc/ic68oy3gIx prfTZcy93arZownv1rK1Raamli40CX9F5omRCZHUxpyVw46SmGCGYxZ/eRmuQHdC1m1s dxI55apHmr6sl10vN3OFFwlPMAa7SKqKVglXLhrLZ3YsP9wGMuq21krYmlvHOJp85UzF KO20WGQyGvnYqcwNdXUA7QJNXQ40a+uLDguQNEBoQfPh+LmZuKVsp5DCCmPf7s1lxOPY d2nbqeUER1KdFo7+Sm2qHkjwMk46WVeb4uOmISqj3HWGfTXxRxK2xv5HNmCn3vGj3MVD GVHA== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 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 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , Suzuki K Poulose , Will Deacon , Catalin Marinas , Greg Hackmann , Alex Shi , Mark Rutland Subject: [PATCH 4.9 067/102] arm64: Take into account ID_AA64PFR0_EL1.CSV3 Date: Fri, 6 Apr 2018 15:23:48 +0200 Message-Id: <20180406084340.929989915@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180406084331.507038179@linuxfoundation.org> References: <20180406084331.507038179@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review 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?1597004075069112100?= X-GMAIL-MSGID: =?utf-8?q?1597004075069112100?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.9-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 [Alex: s/read_sanitised_ftr_reg/read_system_reg/ to match v4.9 naming] Signed-off-by: Alex Shi [v4.9 backport] [Mark: correct zero bits in ftr_id_aa64pfr0 to account for CSV3] Signed-off-by: Mark Rutland [v4.9 backport] Tested-by: Will Deacon Tested-by: Greg Hackmann Signed-off-by: Greg Kroah-Hartman --- arch/arm64/include/asm/sysreg.h | 1 + arch/arm64/kernel/cpufeature.c | 10 ++++++++-- 2 files changed, 9 insertions(+), 2 deletions(-) --- a/arch/arm64/include/asm/sysreg.h +++ b/arch/arm64/include/asm/sysreg.h @@ -117,6 +117,7 @@ #define ID_AA64ISAR0_AES_SHIFT 4 /* id_aa64pfr0 */ +#define ID_AA64PFR0_CSV3_SHIFT 60 #define ID_AA64PFR0_GIC_SHIFT 24 #define ID_AA64PFR0_ASIMD_SHIFT 20 #define ID_AA64PFR0_FP_SHIFT 16 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -93,7 +93,8 @@ static const struct arm64_ftr_bits ftr_i }; static const struct arm64_ftr_bits ftr_id_aa64pfr0[] = { - ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, 32, 32, 0), + ARM64_FTR_BITS(FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_CSV3_SHIFT, 4, 0), + ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, 32, 28, 0), ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, 28, 4, 0), ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, ID_AA64PFR0_GIC_SHIFT, 4, 0), S_ARM64_FTR_BITS(FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_ASIMD_SHIFT, 4, ID_AA64PFR0_ASIMD_NI), @@ -752,6 +753,8 @@ static int __kpti_forced; /* 0: not forc static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry, int __unused) { + u64 pfr0 = read_system_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", @@ -763,7 +766,9 @@ 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) @@ -865,6 +870,7 @@ 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,