x86 microcode: revert some work_on_cpu

Revert part of af5c820a3169e81af869c113e18ec7588836cd50 ("x86: cpumask:
use work_on_cpu in arch/x86/kernel/microcode_core.c")

That change is causing only one Intel CPU's microcode to be updated e.g.
microcode: CPU3 updated from revision 0x9 to 0x17, date = 2005-04-22
where before it announced that also for CPU0 and CPU1 and CPU2.

We cannot use work_on_cpu() in the CONFIG_MICROCODE_OLD_INTERFACE code,
because Intel's request_microcode_user() involves a copy_from_user() from
/sbin/microcode_ctl, which therefore needs to be on that CPU at the time.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/x86/kernel/microcode_core.c b/arch/x86/kernel/microcode_core.c
index a0f3851ef310dcb3e8d419e8a9788b51b3ace3c8..2e0eb414095159040a1dbb188020fe65ecb84e95 100644 (file)
--- a/arch/x86/kernel/microcode_core.c
+++ b/arch/x86/kernel/microcode_core.c
@@ -108,40 +108,29 @@ struct ucode_cpu_info             ucode_cpu_info[NR_CPUS];
 EXPORT_SYMBOL_GPL(ucode_cpu_info);
 
 #ifdef CONFIG_MICROCODE_OLD_INTERFACE
-struct update_for_cpu {
-       const void __user       *buf;
-       size_t                  size;
-};
-
-static long update_for_cpu(void *_ufc)
-{
-       struct update_for_cpu *ufc = _ufc;
-       int error;
-
-       error = microcode_ops->request_microcode_user(smp_processor_id(),
-                                                     ufc->buf, ufc->size);
-       if (error < 0)
-               return error;
-       if (!error)
-               microcode_ops->apply_microcode(smp_processor_id());
-       return error;
-}
-
 static int do_microcode_update(const void __user *buf, size_t size)
 {
+       cpumask_t old;
        int error = 0;
        int cpu;
-       struct update_for_cpu ufc = { .buf = buf, .size = size };
+
+       old = current->cpus_allowed;
 
        for_each_online_cpu(cpu) {
                struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
 
                if (!uci->valid)
                        continue;
-               error = work_on_cpu(cpu, update_for_cpu, &ufc);
+
+               set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));
+               error = microcode_ops->request_microcode_user(cpu, buf, size);
                if (error < 0)
-                       break;
+                       goto out;
+               if (!error)
+                       microcode_ops->apply_microcode(cpu);
        }
+out:
+       set_cpus_allowed_ptr(current, &old);
        return error;
 }