[PATCH v2 2/5] x86/cpuid: refactor setup_clear_cpu_cap()/clear_cpu_cap()

Maxim Levitsky
2022-07-18T14:11:56Z

Currently setup_clear_cpu_cap passes NULL 'struct cpuinfo_x86*'
to clear_cpu_cap to indicate that capability should be cleared from boot_cpu_data.

Later that is used in clear_feature to do recursive call to
clear_cpu_cap together with clearing the feature bit from 'cpu_caps_cleared'

Remove that code and just call the do_clear_cpu_cap on boot_cpu_data directly
from the setup_clear_cpu_cap.

The only functional change this introduces is that now calling clear_cpu_cap
explicitly on boot_cpu_data also sets the bits in cpu_caps_cleared,
which is the only thing that makes sense anyway.

All callers of both functions were checked for this and fixed.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
---
arch/x86/kernel/cpu/cpuid-deps.c | 17 +++++------------
1 file changed, 5 insertions(+), 12 deletions(-)

diff --git a/arch/x86/kernel/cpu/cpuid-deps.c b/arch/x86/kernel/cpu/cpuid-deps.c
index c881bcafba7d70..d6777d07ba3302 100644
--- a/arch/x86/kernel/cpu/cpuid-deps.c
+++ b/arch/x86/kernel/cpu/cpuid-deps.c
@@ -88,18 +88,16 @@ static inline void clear_feature(struct cpuinfo_x86 *c, unsigned int feature)
* 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);
+ clear_bit(feature, (unsigned long *)c->x86_capability);
+
+ if (c == &boot_cpu_data)
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 */
#define MAX_FEATURE_BITS ((NCAPINTS + NBUGINTS) * sizeof(u32) * 8)

-static void do_clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int feature)
+void clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int feature)
{
DECLARE_BITMAP(disable, MAX_FEATURE_BITS);
const struct cpuid_dep *d;
@@ -129,12 +127,7 @@ static void do_clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int feature)
} while (changed);
}

-void clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int feature)
-{
- do_clear_cpu_cap(c, feature);
-}
-
void setup_clear_cpu_cap(unsigned int feature)
{
- do_clear_cpu_cap(NULL, feature);
+ clear_cpu_cap(&boot_cpu_data, feature);
}
--
2.34.3