This is a note to let you know that I've just added the patch titled
x86/init: Clear 'init_level4_pgt' earlier
to the 4.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
x86-init-clear-init_level4_pgt-earlier.patch
and it can be found in the queue-4.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From d0f77d4d04b222a817925d33ba3589b190bfa863 Mon Sep 17 00:00:00 2001
From: Andrey Ryabinin <a.ryabinin@xxxxxxxxxxx>
Date: Thu, 2 Jul 2015 12:09:33 +0300
Subject: x86/init: Clear 'init_level4_pgt' earlier
From: Andrey Ryabinin <a.ryabinin@xxxxxxxxxxx>
commit d0f77d4d04b222a817925d33ba3589b190bfa863 upstream.
Currently x86_64_start_kernel() has two KASAN related
function calls. The first call maps shadow to early_level4_pgt,
the second maps shadow to init_level4_pgt.
If we move clear_page(init_level4_pgt) earlier, we could hide
KASAN low level detail from generic x86_64 initialization code.
The next patch will do it.
Signed-off-by: Andrey Ryabinin <a.ryabinin@xxxxxxxxxxx>
Cc: Alexander Popov <alpopov@xxxxxxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Andrey Konovalov <adech.fo@xxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1435828178-10975-2-git-send-email-a.ryabinin@xxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/head64.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -166,6 +166,8 @@ asmlinkage __visible void __init x86_64_
/* clear bss before set_intr_gate with early_idt_handler */
clear_bss();
+ clear_page(init_level4_pgt);
+
for (i = 0; i < NUM_EXCEPTION_VECTORS; i++)
set_intr_gate(i, early_idt_handler_array[i]);
load_idt((const struct desc_ptr *)&idt_descr);
@@ -177,7 +179,6 @@ asmlinkage __visible void __init x86_64_
*/
load_ucode_bsp();
- clear_page(init_level4_pgt);
/* set init_level4_pgt kernel high mapping*/
init_level4_pgt[511] = early_level4_pgt[511];
Patches currently in stable-queue which might be from a.ryabinin@xxxxxxxxxxx are
queue-4.1/x86-kasan-fix-kasan-shadow-region-page-tables.patch
queue-4.1/x86-kasan-fix-boot-crash-on-amd-processors.patch
queue-4.1/x86-init-clear-init_level4_pgt-earlier.patch
queue-4.1/x86-kasan-flush-tlbs-after-switching-cr3.patch
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