x86/CPU: Add a microcode loader callback

Add a callback function which the microcode loader calls when microcode
has been updated to a newer revision. Do the callback only when no error
was encountered during loading.

Tested-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Ashok Raj <ashok.raj@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20180216112640.11554-3-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 1bd9ed87606f45f5a22f2510bde9ba34029a0551..b0ccd4847a58ab671476f412905a1df912029f1a 100644 (file)
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -977,4 +977,5 @@ bool xen_set_default_idle(void);
 
 void stop_this_cpu(void *dummy);
 void df_debug(struct pt_regs *regs, long error_code);
+void microcode_check(void);
 #endif /* _ASM_X86_PROCESSOR_H */

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 824aee0117bb5402d52fb5c8958e98b0bebfdf0c..84f1cd88608b1a9ab44684f6cc91d2df09cb3320 100644 (file)
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1749,3 +1749,13 @@ static int __init init_cpu_syscore(void)
        return 0;
 }
 core_initcall(init_cpu_syscore);
+
+/*
+ * 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.
+ */
+void microcode_check(void)
+{
+       perf_check_microcode();
+}

diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index 6fdaf7cf3182db6e00c9c456421942376e37163a..aa1b9a422f2be0daf18a7084837165172ef0fafb 100644 (file)
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -509,6 +509,7 @@ static ssize_t reload_store(struct device *dev,
                            const char *buf, size_t size)
 {
        enum ucode_state tmp_ret = UCODE_OK;
+       bool do_callback = false;
        unsigned long val;
        ssize_t ret = 0;
        int cpu;
@@ -531,10 +532,13 @@ static ssize_t reload_store(struct device *dev,
                        if (!ret)
                                ret = -EINVAL;
                }
+
+               if (tmp_ret == UCODE_UPDATED)
+                       do_callback = true;
        }
 
-       if (!ret && tmp_ret == UCODE_UPDATED)
-               perf_check_microcode();
+       if (!ret && do_callback)
+               microcode_check();
 
        mutex_unlock(&microcode_mutex);
        put_online_cpus();