[PATCH 4.14 056/159] x86/cpuid: Replace set/clear_bit32()

Greg Kroah-Hartman
2017-12-22T09:00:47Z

From: Thomas Gleixner <tglx@linutronix.de>

commit 06dd688ddda5819025e014b79aea9af6ab475fa2 upstream.

Peter pointed out that the set/clear_bit32() variants are broken in various
aspects.

Replace them with open coded set/clear_bit() and type cast
cpu_info::x86_capability as it's done in all other places throughout x86.

Fixes: 0b00de857a64 ("x86/cpuid: Add generic table for CPUID dependencies")
Reported-by: Peter Ziljstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/x86/kernel/cpu/cpuid-deps.c | 26 +++++++++++---------------
1 file changed, 11 insertions(+), 15 deletions(-)

--- a/arch/x86/kernel/cpu/cpuid-deps.c
+++ b/arch/x86/kernel/cpu/cpuid-deps.c
@@ -62,23 +62,19 @@ const static struct cpuid_dep cpuid_deps
{}
};

-static inline void __clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int bit)
-{
- clear_bit32(bit, c->x86_capability);
-}
-
-static inline void __setup_clear_cpu_cap(unsigned int bit)
-{
- clear_cpu_cap(&boot_cpu_data, bit);
- set_bit32(bit, cpu_caps_cleared);
-}
-
static inline void clear_feature(struct cpuinfo_x86 *c, unsigned int feature)
{
- if (!c)
- __setup_clear_cpu_cap(feature);
- else
- __clear_cpu_cap(c, feature);
+ /*
+ * Note: This could use the non atomic __*_bit() variants, but the
+ * rest of the cpufeature code uses atomics as well, so keep it for
+ * consistency. Cleanup all of it separately.
+ */
+ if (!c) {
+ clear_cpu_cap(&boot_cpu_data, feature);
+ set_bit(feature, (unsigned long *)cpu_caps_cleared);
+ } else {
+ clear_bit(feature, (unsigned long *)c->x86_capability);
+ }
}

/* Take the capabilities and the BUG bits into account */