Commit-ID:  8877ebdd3f9a3ffc84c4b67562d257c5f553bc49
Gitweb:     http://git.kernel.org/tip/8877ebdd3f9a3ffc84c4b67562d257c5f553bc49
Author:     Borislav Petkov <b...@suse.de>
AuthorDate: Tue, 20 Dec 2016 11:54:30 +0100
Committer:  Thomas Gleixner <t...@linutronix.de>
CommitDate: Wed, 21 Dec 2016 10:50:04 +0100

x86/microcode/AMD: Reload proper initrd start address

When we switch to virtual addresses and, especially after
reserve_initrd()->relocate_initrd() have run, we have the updated initrd
address in initrd_start. Use initrd_start then instead of the address
which has been passed to us through boot params. (That still gets used
when we're running the very early routines on the BSP).

Reported-and-tested-by: Boris Ostrovsky <boris.ostrov...@oracle.com>
Signed-off-by: Borislav Petkov <b...@suse.de>
Link: http://lkml.kernel.org/r/20161220144012.lc4cwrg6dphqb...@pd.tnic
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
---
 arch/x86/kernel/cpu/microcode/core.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kernel/cpu/microcode/core.c 
b/arch/x86/kernel/cpu/microcode/core.c
index c4bb2f7..2af69d2 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -243,14 +243,12 @@ struct cpio_data find_microcode_in_initrd(const char 
*path, bool use_pa)
 # endif
 
        /*
-        * Did we relocate the ramdisk?
-        *
-        * So we possibly relocate the ramdisk *after* applying microcode on the
-        * BSP so we rely on use_pa (use physical addresses) - even if it is not
-        * absolutely correct - to determine whether we've done the ramdisk
-        * relocation already.
+        * Fixup the start address: after reserve_initrd() runs, initrd_start
+        * has the virtual address of the beginning of the initrd. It also
+        * possibly relocates the ramdisk. In either case, initrd_start contains
+        * the updated address so use that instead.
         */
-       if (!use_pa && relocated_ramdisk)
+       if (!use_pa && initrd_start)
                start = initrd_start;
 
        return find_cpio_data(path, (void *)start, size, NULL);

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