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x86/microcode: Remove microcode_mutex

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microcode_mutex is only used by reload_store(). It has a comment saying
"to synchronize with each other". Other user of this mutex have been
removed in the commits

  181b6f40e9 ("x86/microcode: Rip out the OLD_INTERFACE").
  b6f86689d5 ("x86/microcode: Rip out the subsys interface gunk")

The sysfs interface does not need additional synchronisation vs itself
because it is provided as kernfs_ops::mutex which is acquired in
kernfs_fop_write_iter().

Remove the superfluous microcode_mutex.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Sohil Mehta <sohil.mehta@intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230804075853.JF_n6GXC@linutronix.de
This commit is contained in:
Sebastian Andrzej Siewior 2023-08-04 09:58:53 +02:00 committed by Borislav Petkov (AMD)
parent 05e91e7211
commit 80347cd515
2 changed files with 1 additions and 8 deletions
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3
arch/x86/kernel/cpu/common.c
View File

@ -2276,8 +2276,7 @@ void store_cpu_caps(struct cpuinfo_x86 *curr_info)
* @prev_info: CPU capabilities stored before an update.
*
* The microcode loader calls this upon late microcode load to recheck features,
* only when microcode has been updated. Caller holds microcode_mutex and CPU
* hotplug lock.
* only when microcode has been updated. Caller holds and CPU hotplug lock.
*
* Return: None
*/

6
arch/x86/kernel/cpu/microcode/core.c
View File

@ -54,15 +54,12 @@ LIST_HEAD(microcode_cache);
*
* All non cpu-hotplug-callback call sites use:
*
* - microcode_mutex to synchronize with each other;
* - cpus_read_lock/unlock() to synchronize with
* the cpu-hotplug-callback call sites.
*
* We guarantee that only a single cpu is being
* updated at any particular moment of time.
*/
static DEFINE_MUTEX(microcode_mutex);
struct ucode_cpu_info ucode_cpu_info[NR_CPUS];
struct cpu_info_ctx {
@ -488,10 +485,7 @@ static ssize_t reload_store(struct device *dev,
if (tmp_ret != UCODE_NEW)
goto put;
mutex_lock(&microcode_mutex);
ret = microcode_reload_late();
mutex_unlock(&microcode_mutex);
put:
cpus_read_unlock();