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[tip:x86/urgent] x86/microcode/AMD: Reload proper initrd start address

From tip-bot for Borislav Petkov <tipbot@zytor.com>
Newsgroups linux.kernel
Subject [tip:x86/urgent] x86/microcode/AMD: Reload proper initrd start address
Date 2016-12-21 11:00 +0100
Message-ID <sQLQJ-1IF-5@gated-at.bofh.it> (permalink)
References <sQtTP-6Qf-13@gated-at.bofh.it>
Organization linux.* mail to news gateway

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Commit-ID:  8877ebdd3f9a3ffc84c4b67562d257c5f553bc49
Gitweb:     http://git.kernel.org/tip/8877ebdd3f9a3ffc84c4b67562d257c5f553bc49
Author:     Borislav Petkov <bp@suse.de>
AuthorDate: Tue, 20 Dec 2016 11:54:30 +0100
Committer:  Thomas Gleixner <tglx@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.ostrovsky@oracle.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/20161220144012.lc4cwrg6dphqbyqu@pd.tnic
Signed-off-by: Thomas Gleixner <tglx@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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Thread

Re: [PATCH] x86/microcode: Adjust ramdisk address when accessing by  virtual address Borislav Petkov <bp@alien8.de> - 2016-12-19 16:40 +0100
  Re: [PATCH] x86/microcode: Adjust ramdisk address when accessing by  virtual address Borislav Petkov <bp@alien8.de> - 2016-12-19 17:50 +0100
    Re: [PATCH] x86/microcode: Adjust ramdisk address when accessing by  virtual address Borislav Petkov <bp@alien8.de> - 2016-12-19 19:10 +0100
      Re: [PATCH] x86/microcode: Adjust ramdisk address when accessing by  virtual address Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2016-12-19 19:20 +0100
        Re: [PATCH] x86/microcode: Adjust ramdisk address when accessing by  virtual address Borislav Petkov <bp@alien8.de> - 2016-12-19 19:50 +0100
          Re: [PATCH] x86/microcode: Adjust ramdisk address when accessing by  virtual address Borislav Petkov <bp@alien8.de> - 2016-12-20 00:40 +0100
            Re: [PATCH] x86/microcode: Adjust ramdisk address when accessing by  virtual address Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2016-12-20 02:30 +0100
              Re: [PATCH] x86/microcode: Adjust ramdisk address when accessing by  virtual address Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2016-12-20 02:50 +0100
                Re: [PATCH] x86/microcode: Adjust ramdisk address when accessing by  virtual address Borislav Petkov <bp@alien8.de> - 2016-12-20 15:50 +0100
                Re: [PATCH] x86/microcode: Adjust ramdisk address when accessing by  virtual address Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2016-12-20 20:30 +0100
                Re: [PATCH] x86/microcode: Adjust ramdisk address when accessing by  virtual address Borislav Petkov <bp@alien8.de> - 2016-12-20 20:40 +0100
                Re: [PATCH] x86/microcode: Adjust ramdisk address when accessing by  virtual address Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2016-12-20 23:50 +0100
                Re: [PATCH] x86/microcode: Adjust ramdisk address when accessing by  virtual address Borislav Petkov <bp@alien8.de> - 2016-12-21 00:00 +0100
                [tip:x86/urgent] x86/microcode/AMD: Reload proper initrd start  address tip-bot for Borislav Petkov <tipbot@zytor.com> - 2016-12-21 11:00 +0100

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