[PATCH] NX protection for kernel data : fix xen boot

[PATCH] NX protection for kernel data : fix xen boot

[matthieu castet]

[-- Attachment #1: Type: text/plain, Size: 133 bytes --]

I think it should be applied before 2.6.38 release, because without
this patch xen doesn't boot on x86_32 with CONFIG_DEBUG_RODATA.


[-- Attachment #2: 0001-NX-protection-for-kernel-data-fix-xen-boot.patch --]
[-- Type: text/x-diff, Size: 1940 bytes --]

>From 08f54ec4007ab0df231d81ed436632aa7f605feb Mon Sep 17 00:00:00 2001
From: Matthieu CASTET <castet.matthieu@free.fr>
Date: Thu, 20 Jan 2011 21:11:45 +0100
Subject: [PATCH] NX protection for kernel data : fix xen boot

Xen want page table pages read only.

But the initial page table (from head_*.S) live in .data or .bss.

That was broken by 64edc8ed5ffae999d8d413ba006850e9e34166cb.
Revert the problematic part as it is only a protection and
not really needed.

Signed-off-by: Matthieu CASTET <castet.matthieu@free.fr>
Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 arch/x86/mm/pageattr.c |    8 --------
 1 files changed, 0 insertions(+), 8 deletions(-)

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 2ad6c48..951eb4a 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -256,7 +256,6 @@ static inline pgprot_t static_protections(pgprot_t prot, unsigned long address,
 				   unsigned long pfn)
 {
 	pgprot_t forbidden = __pgprot(0);
-	pgprot_t required = __pgprot(0);
 
 	/*
 	 * The BIOS area between 640k and 1Mb needs to be executable for
@@ -286,12 +285,6 @@ static inline pgprot_t static_protections(pgprot_t prot, unsigned long address,
 	if (within(pfn, __pa((unsigned long)__start_rodata) >> PAGE_SHIFT,
 		   __pa((unsigned long)__end_rodata) >> PAGE_SHIFT))
 		pgprot_val(forbidden) |= _PAGE_RW;
-	/*
-	 * .data and .bss should always be writable.
-	 */
-	if (within(address, (unsigned long)_sdata, (unsigned long)_edata) ||
-	    within(address, (unsigned long)__bss_start, (unsigned long)__bss_stop))
-		pgprot_val(required) |= _PAGE_RW;
 
 #if defined(CONFIG_X86_64) && defined(CONFIG_DEBUG_RODATA)
 	/*
@@ -331,7 +324,6 @@ static inline pgprot_t static_protections(pgprot_t prot, unsigned long address,
 #endif
 
 	prot = __pgprot(pgprot_val(prot) & ~pgprot_val(forbidden));
-	prot = __pgprot(pgprot_val(prot) | pgprot_val(required));
 
 	return prot;
 }
-- 
1.7.2.3

[PATCH] NX protection for kernel data : fix xen boot

[matthieu castet]

[-- Attachment #1: Type: text/plain, Size: 141 bytes --]

I think it should be applied before 2.6.38 release, because without
this patch S3 suspend doesn't work on x86_32 with CONFIG_DEBUG_RODATA.



[-- Attachment #2: 0001-NX-protection-for-kernel-data-fix-32-bits-wakeup.patch --]
[-- Type: text/x-diff, Size: 1907 bytes --]

>From 8e4bdefe9649a89c972974d94510f0c2bd2d0ea4 Mon Sep 17 00:00:00 2001
From: Matthieu CASTET <castet.matthieu@free.fr>
Date: Thu, 27 Jan 2011 21:36:07 +0100
Subject: [PATCH] NX protection for kernel data : fix 32 bits wakeup

32 bits wakeup realmode trampoline enable paging, while still
in low memory.

We should make this memory !NX in order it works.

Signed-off-by: Matthieu CASTET <castet.matthieu@free.fr>
Tested-by: Matthias Hopf <mhopf@suse.de>
---
 arch/x86/mm/init_32.c  |    8 ++++++++
 arch/x86/mm/pageattr.c |    7 +++++++
 2 files changed, 15 insertions(+), 0 deletions(-)

diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index c821074..0048738 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -227,6 +227,14 @@ page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base)
 
 static inline int is_kernel_text(unsigned long addr)
 {
+#if defined(CONFIG_X86_32) && defined(CONFIG_ACPI_SLEEP)
+	/*
+	 * We need to make the wakeup trampoline in first 1MB !NX
+	 */
+	if (addr >= PAGE_OFFSET && addr <= (PAGE_OFFSET + (1<<20)))
+		return 1;
+#endif
+
 	if (addr >= (unsigned long)_text && addr <= (unsigned long)__init_end)
 		return 1;
 	return 0;
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index d343b3c..f1d6cf5 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -265,6 +265,13 @@ static inline pgprot_t static_protections(pgprot_t prot, unsigned long address,
 	if (pcibios_enabled && within(pfn, BIOS_BEGIN >> PAGE_SHIFT, BIOS_END >> PAGE_SHIFT))
 		pgprot_val(forbidden) |= _PAGE_NX;
 #endif
+	/*
+	 * We need to make the wakeup trampoline in first 1MB !NX
+	 */
+#if defined(CONFIG_X86_32) && defined(CONFIG_ACPI_SLEEP)
+	if (within(address, PAGE_OFFSET, PAGE_OFFSET + (1<<20)))
+		pgprot_val(forbidden) |= _PAGE_NX;
+#endif
 
 	/*
 	 * The kernel text needs to be executable for obvious reasons
-- 
1.7.2.3