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List:       linux-mm
Subject:    [tip:x86/urgent] x86/microcode/AMD: Fix more fallout from CONFIG_RANDOMIZE_MEMORY=y
From:       tip-bot for Borislav Petkov <tipbot () zytor ! com>
Date:       2016-10-28 8:37:49
Message-ID: tip-1c27f646b18fb56308dff82784ca61951bad0b48 () git ! kernel ! org
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Commit-ID:  1c27f646b18fb56308dff82784ca61951bad0b48
Gitweb:     http://git.kernel.org/tip/1c27f646b18fb56308dff82784ca61951bad0b48
Author:     Borislav Petkov <bp@suse.de>
AuthorDate: Thu, 27 Oct 2016 14:36:23 +0200
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 28 Oct 2016 10:29:59 +0200

x86/microcode/AMD: Fix more fallout from CONFIG_RANDOMIZE_MEMORY=y

We needed the physical address of the container in order to compute the
offset within the relocated ramdisk. And we did this by doing __pa() on
the virtual address.

However, __pa() does checks whether the physical address is within
PAGE_OFFSET and __START_KERNEL_map - see __phys_addr() - which fail
if we have CONFIG_RANDOMIZE_MEMORY enabled: we feed a virtual address
which *doesn't* have the randomization offset into a function which uses
PAGE_OFFSET which *does* have that offset.

This makes this check fire:

	VIRTUAL_BUG_ON((x > y) || !phys_addr_valid(x));
			^^^^^^

due to the randomization offset.

The fix is as simple as using __pa_nodebug() because we do that
randomization offset accounting later in that function ourselves.

Reported-by: Bob Peterson <rpeterso@redhat.com>
Tested-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm <linux-mm@kvack.org>
Cc: stable@vger.kernel.org # 4.9
Link: http://lkml.kernel.org/r/20161027123623.j2jri5bandimboff@pd.tnic
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/kernel/cpu/microcode/amd.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c
index 620ab06..017bda1 100644
--- a/arch/x86/kernel/cpu/microcode/amd.c
+++ b/arch/x86/kernel/cpu/microcode/amd.c
@@ -429,7 +429,7 @@ int __init save_microcode_in_initrd_amd(void)
 	 * We need the physical address of the container for both bitness since
 	 * boot_params.hdr.ramdisk_image is a physical address.
 	 */
-	cont    = __pa(container);
+	cont    = __pa_nodebug(container);
 	cont_va = container;
 #endif
 

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