linux-kernel - [PATCH 4.8 041/138] x86/microcode/AMD: Fix more fallout from CONFIG_RANDOMIZE

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Message-Id: <20161109102846.562244037@linuxfoundation.org>
Date:   Wed,  9 Nov 2016 11:45:24 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Bob Peterson <rpeterso@...hat.com>,
        Borislav Petkov <bp@...e.de>,
        Andreas Gruenbacher <agruenba@...hat.com>,
        Andy Lutomirski <luto@...capital.net>,
        Andy Lutomirski <luto@...nel.org>,
        Borislav Petkov <bp@...en8.de>,
        Brian Gerst <brgerst@...il.com>,
        Denys Vlasenko <dvlasenk@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Mel Gorman <mgorman@...hsingularity.net>,
        Peter Zijlstra <peterz@...radead.org>,
        Steven Whitehouse <swhiteho@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        linux-mm <linux-mm@...ck.org>, Ingo Molnar <mingo@...nel.org>
Subject: [PATCH 4.8 041/138] x86/microcode/AMD: Fix more fallout from CONFIG_RANDOMIZE_MEMORY=y

4.8-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Borislav Petkov <bp@...e.de>

commit 1c27f646b18fb56308dff82784ca61951bad0b48 upstream.

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@...hat.com>
Tested-by: Bob Peterson <rpeterso@...hat.com>
Signed-off-by: Borislav Petkov <bp@...e.de>
Cc: Andreas Gruenbacher <agruenba@...hat.com>
Cc: Andy Lutomirski <luto@...capital.net>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Brian Gerst <brgerst@...il.com>
Cc: Denys Vlasenko <dvlasenk@...hat.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Josh Poimboeuf <jpoimboe@...hat.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Mel Gorman <mgorman@...hsingularity.net>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Steven Whitehouse <swhiteho@...hat.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: linux-mm <linux-mm@...ck.org>
Link: http://lkml.kernel.org/r/20161027123623.j2jri5bandimboff@pd.tnic
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/x86/kernel/cpu/microcode/amd.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- 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(
 	 * 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