x86/microcode/intel: Make early loader look for builtin microcode too

Set the initrd @start depending on the presence of an initrd. Otherwise,
builtin microcode loading doesn't work as the start is wrong and we're
using it to compute offset to the microcode blobs.

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/1454499225-21544-3-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index 044bbbbcbaf167494bb5f3ebacbf2c6b392cab89..4f4735bd86983573a3ed387c0246d56f1bf82392 100644 (file)
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -551,10 +551,14 @@ scan_microcode(struct mc_saved_data *mc_saved_data, unsigned long *initrd,
        cd.data = NULL;
        cd.size = 0;
 
-       cd = find_cpio_data(p, (void *)start, size, &offset);
-       if (!cd.data) {
+       /* try built-in microcode if no initrd */
+       if (!size) {
                if (!load_builtin_intel_microcode(&cd))
                        return UCODE_ERROR;
+       } else {
+               cd = find_cpio_data(p, (void *)start, size, &offset);
+               if (!cd.data)
+                       return UCODE_ERROR;
        }
 
        return get_matching_model_microcode(0, start, cd.data, cd.size,
@@ -728,16 +732,20 @@ void __init load_ucode_intel_bsp(void)
        struct boot_params *p;
 
        p       = (struct boot_params *)__pa_nodebug(&boot_params);
-       start   = p->hdr.ramdisk_image;
        size    = p->hdr.ramdisk_size;
 
-       _load_ucode_intel_bsp(
-                       (struct mc_saved_data *)__pa_nodebug(&mc_saved_data),
-                       (unsigned long *)__pa_nodebug(&mc_saved_in_initrd),
-                       start, size);
+       /*
+        * Set start only if we have an initrd image. We cannot use initrd_start
+        * because it is not set that early yet.
+        */
+       start   = (size ? p->hdr.ramdisk_image : 0);
+
+       _load_ucode_intel_bsp((struct mc_saved_data *)__pa_nodebug(&mc_saved_data),
+                             (unsigned long *)__pa_nodebug(&mc_saved_in_initrd),
+                             start, size);
 #else
-       start   = boot_params.hdr.ramdisk_image + PAGE_OFFSET;
        size    = boot_params.hdr.ramdisk_size;
+       start   = (size ? boot_params.hdr.ramdisk_image + PAGE_OFFSET : 0);
 
        _load_ucode_intel_bsp(&mc_saved_data, mc_saved_in_initrd, start, size);
 #endif