[patch 10/30] x86/microcode: Remove pointless mutex

From: Thomas Gleixner
Date: Thu Aug 10 2023 - 14:38:07 EST


From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

There is no concurreny.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

---
arch/x86/kernel/cpu/microcode/intel.c | 24 ++----------------------
1 file changed, 2 insertions(+), 22 deletions(-)
---
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -302,22 +302,6 @@ scan_microcode(void *data, size_t size,
return patch;
}

-/*
- * Save this microcode patch. It will be loaded early when a CPU is
- * hot-added or resumes.
- */
-static void save_mc_for_early(struct ucode_cpu_info *uci, u8 *mc, unsigned int size)
-{
- /* Synchronization during CPU hotplug. */
- static DEFINE_MUTEX(x86_cpu_microcode_mutex);
-
- mutex_lock(&x86_cpu_microcode_mutex);
-
- save_microcode_patch(mc, size);
-
- mutex_unlock(&x86_cpu_microcode_mutex);
-}
-
static bool load_builtin_intel_microcode(struct cpio_data *cp)
{
unsigned int eax = 1, ebx, ecx = 0, edx;
@@ -718,12 +702,8 @@ static enum ucode_state generic_load_mic
vfree(uci->mc);
uci->mc = (struct microcode_intel *)new_mc;

- /*
- * If early loading microcode is supported, save this mc into
- * permanent memory. So it will be loaded early when a CPU is hot added
- * or resumes.
- */
- save_mc_for_early(uci, new_mc, new_mc_size);
+ /* Save for CPU hotplug */
+ save_microcode_patch(new_mc, new_mc_size);

pr_debug("CPU%d found a matching microcode update with version 0x%x (current=0x%x)\n",
cpu, new_rev, uci->cpu_sig.rev);