04f3b8beca
and allow loading of microcode on recent AMD systems in preparation of further Spectre fixes
55 lines
2.0 KiB
Diff
55 lines
2.0 KiB
Diff
From 5462db3d070845ecc34929b6f25a87efda023aae Mon Sep 17 00:00:00 2001
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From: Tom Lendacky <thomas.lendacky@amd.com>
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Date: Tue, 26 Dec 2017 23:43:54 -0600
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Subject: [PATCH 240/241] x86/cpu, x86/pti: Do not enable PTI on AMD processors
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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CVE-2017-5754
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AMD processors are not subject to the types of attacks that the kernel
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page table isolation feature protects against. The AMD microarchitecture
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does not allow memory references, including speculative references, that
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access higher privileged data when running in a lesser privileged mode
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when that access would result in a page fault.
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Disable page table isolation by default on AMD processors by not setting
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the X86_BUG_CPU_INSECURE feature, which controls whether X86_FEATURE_PTI
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is set.
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Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Reviewed-by: Borislav Petkov <bp@suse.de>
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Cc: Dave Hansen <dave.hansen@linux.intel.com>
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Cc: Andy Lutomirski <luto@kernel.org>
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Cc: stable@vger.kernel.org
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Link: https://lkml.kernel.org/r/20171227054354.20369.94587.stgit@tlendack-t1.amdoffice.net
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(cherry picked from commit 694d99d40972f12e59a3696effee8a376b79d7c8)
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Signed-off-by: Marcelo Henrique Cerri <marcelo.cerri@canonical.com>
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(cherry picked from commit 9d334f48f017b9c6457c6ba321e5a53a1cc6a5c7)
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Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
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---
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arch/x86/kernel/cpu/common.c | 4 ++--
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1 file changed, 2 insertions(+), 2 deletions(-)
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diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
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index 99f37d1636ff..1854dd8071a6 100644
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--- a/arch/x86/kernel/cpu/common.c
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+++ b/arch/x86/kernel/cpu/common.c
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@@ -899,8 +899,8 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c)
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setup_force_cpu_cap(X86_FEATURE_ALWAYS);
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- /* Assume for now that ALL x86 CPUs are insecure */
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- setup_force_cpu_bug(X86_BUG_CPU_INSECURE);
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+ if (c->x86_vendor != X86_VENDOR_AMD)
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+ setup_force_cpu_bug(X86_BUG_CPU_INSECURE);
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fpu__init_system(c);
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}
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--
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2.14.2
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