This is a note to let you know that I've just added the patch titled
x86-64, init: Do not set NX bits on non-NX capable hardware
to the 3.9-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:
x86-64-init-do-not-set-nx-bits-on-non-nx-capable-hardware.patch
and it can be found in the queue-3.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 78d77df71510a96e042de7ba6dbd7998103642cb Mon Sep 17 00:00:00 2001
From: "H. Peter Anvin" <[email protected]>
Date: Thu, 2 May 2013 10:33:46 -0700
Subject: x86-64, init: Do not set NX bits on non-NX capable hardware
From: "H. Peter Anvin" <[email protected]>
commit 78d77df71510a96e042de7ba6dbd7998103642cb upstream.
During early init, we would incorrectly set the NX bit even if the NX
feature was not supported. Instead, only set this bit if NX is
actually available and enabled. We already do very early detection of
the NX bit to enable it in EFER, this simply extends this detection to
the early page table mask.
Reported-by: Fernando Luis Vázquez Cao <[email protected]>
Signed-off-by: H. Peter Anvin <[email protected]>
Link: http://lkml.kernel.org/r/1367476850.5660.2.camel@nexus
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/kernel/head64.c | 3 ++-
arch/x86/kernel/head_64.S | 1 +
2 files changed, 3 insertions(+), 1 deletion(-)
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -34,6 +34,7 @@
extern pgd_t early_level4_pgt[PTRS_PER_PGD];
extern pmd_t early_dynamic_pgts[EARLY_DYNAMIC_PAGE_TABLES][PTRS_PER_PMD];
static unsigned int __initdata next_early_pgt = 2;
+pmdval_t __initdata early_pmd_flags = __PAGE_KERNEL_LARGE & ~(_PAGE_GLOBAL |
_PAGE_NX);
/* Wipe all early page tables except for the kernel symbol map */
static void __init reset_early_page_tables(void)
@@ -99,7 +100,7 @@ again:
pmd_p[i] = 0;
*pud_p = (pudval_t)pmd_p - __START_KERNEL_map + phys_base +
_KERNPG_TABLE;
}
- pmd = (physaddr & PMD_MASK) + (__PAGE_KERNEL_LARGE & ~_PAGE_GLOBAL);
+ pmd = (physaddr & PMD_MASK) + early_pmd_flags;
pmd_p[pmd_index(address)] = pmd;
return 0;
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -200,6 +200,7 @@ ENTRY(secondary_startup_64)
btl $20,%edi /* No Execute supported? */
jnc 1f
btsl $_EFER_NX, %eax
+ btsq $_PAGE_BIT_NX,early_pmd_flags(%rip)
1: wrmsr /* Make changes effective */
/* Setup cr0 */
Patches currently in stable-queue which might be from [email protected] are
queue-3.9/x86-64-init-do-not-set-nx-bits-on-non-nx-capable-hardware.patch
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