x86/microcode/AMD: Fix initrd loading with CONFIG_RANDOMIZE_MEMORY=y

Similar to:

  efaad554b4ff ("x86/microcode/intel: Fix initrd loading with CONFIG_RANDOMIZE_MEMORY=y")

... fix microcode loading from the initrd on AMD by adding the
randomization offset to the microcode patch container within the initrd.

Reported-and-tested-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-tip-commits@vger.kernel.org
Link: http://lkml.kernel.org/r/20160817113314.GA19221@nazgul.tnic
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 8 insertions, 1 deletions

diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c
index 27a0228c9cae..b816971f5da4 100644
--- a/arch/x86/kernel/cpu/microcode/amd.c
+++ b/arch/x86/kernel/cpu/microcode/amd.c
@@ -355,6 +355,7 @@ void load_ucode_amd_ap(void)
         unsigned int cpu = smp_processor_id();
         struct equiv_cpu_entry *eq;
         struct microcode_amd *mc;
+        u8 *cont = container;
         u32 rev, eax;
         u16 eq_id;
 
@@ -371,8 +372,11 @@ void load_ucode_amd_ap(void)
         if (check_current_patch_level(&rev, false))
                 return;
 
+        /* Add CONFIG_RANDOMIZE_MEMORY offset. */
+        cont += PAGE_OFFSET - __PAGE_OFFSET_BASE;
+
         eax = cpuid_eax(0x00000001);
-        eq  = (struct equiv_cpu_entry *)(container + CONTAINER_HDR_SZ);
+        eq  = (struct equiv_cpu_entry *)(cont + CONTAINER_HDR_SZ);
 
         eq_id = find_equiv_id(eq, eax);
         if (!eq_id)
@@ -434,6 +438,9 @@ int __init save_microcode_in_initrd_amd(void)
         else
                 container = cont_va;
 
+        /* Add CONFIG_RANDOMIZE_MEMORY offset. */
+        container += PAGE_OFFSET - __PAGE_OFFSET_BASE;
+
         eax   = cpuid_eax(0x00000001);
         eax   = ((eax >> 8) & 0xf) + ((eax >> 20) & 0xff);