2018-01-06 14:13:39 +00:00
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From 3e535e66c0bd546a1891c3a8ad6bf6aae7a0829e Mon Sep 17 00:00:00 2001
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From: Thomas Gleixner <tglx@linutronix.de>
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Date: Thu, 2 Nov 2017 13:22:35 +0100
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2018-01-08 09:25:09 +00:00
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Subject: [PATCH 107/241] x86/cpuid: Replace set/clear_bit32()
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2018-01-06 14:13:39 +00:00
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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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Peter pointed out that the set/clear_bit32() variants are broken in various
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aspects.
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Replace them with open coded set/clear_bit() and type cast
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cpu_info::x86_capability as it's done in all other places throughout x86.
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Fixes: 0b00de857a64 ("x86/cpuid: Add generic table for CPUID dependencies")
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Reported-by: Peter Ziljstra <peterz@infradead.org>
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Cc: Andi Kleen <ak@linux.intel.com>
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(cherry picked from commit 06dd688ddda5819025e014b79aea9af6ab475fa2)
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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 3e511952bc3ff9b233d418b0a75a8331deb08171)
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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/cpuid-deps.c | 26 +++++++++++---------------
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1 file changed, 11 insertions(+), 15 deletions(-)
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diff --git a/arch/x86/kernel/cpu/cpuid-deps.c b/arch/x86/kernel/cpu/cpuid-deps.c
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index c21f22d836ad..904b0a3c4e53 100644
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--- a/arch/x86/kernel/cpu/cpuid-deps.c
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+++ b/arch/x86/kernel/cpu/cpuid-deps.c
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@@ -62,23 +62,19 @@ const static struct cpuid_dep cpuid_deps[] = {
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{}
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};
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-static inline void __clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int bit)
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-{
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- clear_bit32(bit, c->x86_capability);
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-}
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-
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-static inline void __setup_clear_cpu_cap(unsigned int bit)
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-{
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- clear_cpu_cap(&boot_cpu_data, bit);
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- set_bit32(bit, cpu_caps_cleared);
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-}
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-
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static inline void clear_feature(struct cpuinfo_x86 *c, unsigned int feature)
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{
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- if (!c)
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- __setup_clear_cpu_cap(feature);
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- else
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- __clear_cpu_cap(c, feature);
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+ /*
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+ * Note: This could use the non atomic __*_bit() variants, but the
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+ * rest of the cpufeature code uses atomics as well, so keep it for
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+ * consistency. Cleanup all of it separately.
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+ */
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+ if (!c) {
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+ clear_cpu_cap(&boot_cpu_data, feature);
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+ set_bit(feature, (unsigned long *)cpu_caps_cleared);
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+ } else {
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+ clear_bit(feature, (unsigned long *)c->x86_capability);
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+ }
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}
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/* Take the capabilities and the BUG bits into account */
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--
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2.14.2
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