83 lines
2.9 KiB
Diff
83 lines
2.9 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Andy Lutomirski <luto@kernel.org>
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Date: Thu, 29 Jun 2017 08:53:20 -0700
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Subject: [PATCH] x86/mm: Add the 'nopcid' boot option to turn off PCID
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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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The parameter is only present on x86_64 systems to save a few bytes,
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as PCID is always disabled on x86_32.
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Signed-off-by: Andy Lutomirski <luto@kernel.org>
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Reviewed-by: Nadav Amit <nadav.amit@gmail.com>
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Reviewed-by: Borislav Petkov <bp@suse.de>
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Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
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Cc: Andrew Morton <akpm@linux-foundation.org>
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Cc: Arjan van de Ven <arjan@linux.intel.com>
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Cc: Borislav Petkov <bp@alien8.de>
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Cc: Dave Hansen <dave.hansen@intel.com>
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Cc: Linus Torvalds <torvalds@linux-foundation.org>
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Cc: Mel Gorman <mgorman@suse.de>
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Cc: Peter Zijlstra <peterz@infradead.org>
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Cc: Rik van Riel <riel@redhat.com>
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Cc: linux-mm@kvack.org
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Link: http://lkml.kernel.org/r/8bbb2e65bcd249a5f18bfb8128b4689f08ac2b60.1498751203.git.luto@kernel.org
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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(cherry picked from commit 0790c9aad84901ca1bdc14746175549c8b5da215)
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Signed-off-by: Andy Whitcroft <apw@canonical.com>
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Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
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(cherry picked from commit 62d3a63645c17611fe8ccc0c5adc5e840d9cff7b)
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Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
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---
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Documentation/admin-guide/kernel-parameters.txt | 2 ++
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arch/x86/kernel/cpu/common.c | 18 ++++++++++++++++++
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2 files changed, 20 insertions(+)
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diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
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index 73fd6abac39b..3510e255ef4c 100644
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--- a/Documentation/admin-guide/kernel-parameters.txt
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+++ b/Documentation/admin-guide/kernel-parameters.txt
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@@ -2700,6 +2700,8 @@
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nopat [X86] Disable PAT (page attribute table extension of
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pagetables) support.
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+ nopcid [X86-64] Disable the PCID cpu feature.
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+
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norandmaps Don't use address space randomization. Equivalent to
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echo 0 > /proc/sys/kernel/randomize_va_space
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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 c8b39870f33e..904485e7b230 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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@@ -168,6 +168,24 @@ static int __init x86_mpx_setup(char *s)
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}
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__setup("nompx", x86_mpx_setup);
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+#ifdef CONFIG_X86_64
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+static int __init x86_pcid_setup(char *s)
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+{
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+ /* require an exact match without trailing characters */
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+ if (strlen(s))
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+ return 0;
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+
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+ /* do not emit a message if the feature is not present */
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+ if (!boot_cpu_has(X86_FEATURE_PCID))
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+ return 1;
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+
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+ setup_clear_cpu_cap(X86_FEATURE_PCID);
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+ pr_info("nopcid: PCID feature disabled\n");
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+ return 1;
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+}
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+__setup("nopcid", x86_pcid_setup);
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+#endif
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+
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static int __init x86_noinvpcid_setup(char *s)
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{
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/* noinvpcid doesn't accept parameters */
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--
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2.14.2
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