NX protection for kernel data : fix xen boot

PATCH New matthieu castet 1 participant 1 message Jan 31, 2011

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matthieu castet

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2011-01-31 23:01 UTC #0 lore raw

PATCH 1/1 NX protection for kernel data : fix xen boot

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.

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From 8e4bdefe9649a89c972974d94510f0c2bd2d0ea4 Mon Sep 17 00:00:00 2001

From: Matthieu CASTET <[email protected]>
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 <[email protected]>

Tested-by Matthias Hopf <[email protected]>

---
 arch/x86/mm/init_32.c  |    8 ++++++++
 arch/x86/mm/pageattr.c |    7 +++++++
 2 files changed, 15 insertions(+), 0 deletions(-)

arch/x86/mm/init_32.c +8 -0

index c821074..0048738 100644
@@ -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;

arch/x86/mm/pageattr.c +7 -0

index d343b3c..f1d6cf5 100644
@@ -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

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