x86/microcode: Untangle from BLK_DEV_INITRD

Thomas Voegtle reported that doing oldconfig with a .config which has
CONFIG_MICROCODE enabled but BLK_DEV_INITRD disabled prevents the
microcode loading mechanism from being built.

So untangle it from the BLK_DEV_INITRD dependency so that oldconfig
doesn't turn it off and add an explanatory text to its Kconfig help what
the supported methods for supplying microcode are.

Reported-by: Thomas Voegtle <tv@lio96.de>
Tested-by: Thomas Voegtle <tv@lio96.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: <stable@vger.kernel.org> # 4.4
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/1454499225-21544-2-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 4 insertions, 10 deletions

diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index ee81c544ee0d..044bbbbcbaf1 100644
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -690,7 +690,7 @@ int __init save_microcode_in_initrd_intel(void)
         if (count == 0)
                 return ret;
 
-        copy_initrd_ptrs(mc_saved, mc_saved_in_initrd, initrd_start, count);
+        copy_initrd_ptrs(mc_saved, mc_saved_in_initrd, get_initrd_start(), count);
         ret = save_microcode(&mc_saved_data, mc_saved, count);
         if (ret)
                 pr_err("Cannot save microcode patches from initrd.\n");
@@ -748,20 +748,14 @@ void load_ucode_intel_ap(void)
         struct mc_saved_data *mc_saved_data_p;
         struct ucode_cpu_info uci;
         unsigned long *mc_saved_in_initrd_p;
-        unsigned long initrd_start_addr;
         enum ucode_state ret;
 #ifdef CONFIG_X86_32
-        unsigned long *initrd_start_p;
 
-        mc_saved_in_initrd_p =
-                (unsigned long *)__pa_nodebug(mc_saved_in_initrd);
+        mc_saved_in_initrd_p = (unsigned long *)__pa_nodebug(mc_saved_in_initrd);
         mc_saved_data_p = (struct mc_saved_data *)__pa_nodebug(&mc_saved_data);
-        initrd_start_p = (unsigned long *)__pa_nodebug(&initrd_start);
-        initrd_start_addr = (unsigned long)__pa_nodebug(*initrd_start_p);
 #else
-        mc_saved_data_p = &mc_saved_data;
         mc_saved_in_initrd_p = mc_saved_in_initrd;
-        initrd_start_addr = initrd_start;
+        mc_saved_data_p = &mc_saved_data;
 #endif
 
         /*
@@ -773,7 +767,7 @@ void load_ucode_intel_ap(void)
 
         collect_cpu_info_early(&uci);
         ret = load_microcode(mc_saved_data_p, mc_saved_in_initrd_p,
-                             initrd_start_addr, &uci);
+                             get_initrd_start_addr(), &uci);
 
         if (ret != UCODE_OK)
                 return;