x86/microcode: Fix return value for microcode late loading

The return value from stop_machine() might not be consistent.

stop_machine_cpuslocked() returns:
- zero if all functions have returned 0.
- a non-zero value if at least one of the functions returned
a non-zero value.

There is no way to know if it is negative or positive. So make
__reload_late() return 0 on success or negative otherwise.

 [ bp: Unify ret val check and touch up. ]

Signed-off-by: Mihai Carabas <mihai.carabas@oracle.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/1587497318-4438-1-git-send-email-mihai.carabas@oracle.com

diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index 7019d4b..baec68b 100644 (file)
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -545,8 +545,7 @@ static int __wait_for_cpus(atomic_t *t, long long timeout)
 /*
  * Returns:
  * < 0 - on error
- *   0 - no update done
- *   1 - microcode was updated
+ *   0 - success (no update done or microcode was updated)
  */
 static int __reload_late(void *info)
 {
@@ -573,11 +572,11 @@ static int __reload_late(void *info)
        else
                goto wait_for_siblings;
 
-       if (err > UCODE_NFOUND) {
-               pr_warn("Error reloading microcode on CPU %d\n", cpu);
+       if (err >= UCODE_NFOUND) {
+               if (err == UCODE_ERROR)
+                       pr_warn("Error reloading microcode on CPU %d\n", cpu);
+
                ret = -1;
-       } else if (err == UCODE_UPDATED || err == UCODE_OK) {
-               ret = 1;
        }
 
 wait_for_siblings:
@@ -608,7 +607,7 @@ static int microcode_reload_late(void)
        atomic_set(&late_cpus_out, 0);
 
        ret = stop_machine_cpuslocked(__reload_late, NULL, cpu_online_mask);
-       if (ret > 0)
+       if (ret == 0)
                microcode_check();
 
        pr_info("Reload completed, microcode revision: 0x%x\n", boot_cpu_data.microcode);
@@ -649,7 +648,7 @@ static ssize_t reload_store(struct device *dev,
 put:
        put_online_cpus();
 
-       if (ret >= 0)
+       if (ret == 0)
                ret = size;
 
        return ret;