lkml.org 
[lkml]   [2020]   [Mar]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] x86/cpufeatures: make bits in cpu_caps_cleared[] and cpu_cpus_set[] exclusive
Date
In apply_forced_caps(), cpu_caps_set[] overrides cpu_caps_cleared[], so
that setup_clear_cpu_cap() cannot clear one cap if setup_force_cpu_cap()
sets the cap before it.

Explicitly clear the bit in cpu_caps_cleared[] when set it in
cpu_caps_set[], and vice versa, can fix this.

Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
---
arch/x86/include/asm/cpufeature.h | 1 +
arch/x86/kernel/cpu/cpuid-deps.c | 1 +
2 files changed, 2 insertions(+)

diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index 59bf91c57aa8..f6d976b05d2c 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -144,6 +144,7 @@ extern void clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int bit);
#define setup_force_cpu_cap(bit) do { \
set_cpu_cap(&boot_cpu_data, bit); \
set_bit(bit, (unsigned long *)cpu_caps_set); \
+ clear_bit(bit, (unsigned long *)cpu_caps_cleared); \
} while (0)

#define setup_force_cpu_bug(bit) setup_force_cpu_cap(bit)
diff --git a/arch/x86/kernel/cpu/cpuid-deps.c b/arch/x86/kernel/cpu/cpuid-deps.c
index 3cbe24ca80ab..e16c36094e6c 100644
--- a/arch/x86/kernel/cpu/cpuid-deps.c
+++ b/arch/x86/kernel/cpu/cpuid-deps.c
@@ -82,6 +82,7 @@ static inline void clear_feature(struct cpuinfo_x86 *c, unsigned int feature)
if (!c) {
clear_cpu_cap(&boot_cpu_data, feature);
set_bit(feature, (unsigned long *)cpu_caps_cleared);
+ clear_bit(feature, (unsigned long *)cpu_caps_set);
} else {
clear_bit(feature, (unsigned long *)c->x86_capability);
}
--
2.20.1
\
 
 \ /
  Last update: 2020-03-18 07:35    [W:0.046 / U:0.008 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site