x86:add function to check BIOS whether NX

PATCH New Wang YanQing 1 participant 1 message Feb 27, 2012

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x86 PCI x86 MM

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Wang YanQing

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2012-02-27 01:02 UTC #0 lore raw

PATCH 1/2 x86:add function to check BIOS whether NX

Although we don't want any RWX memory in system,
but there are still some may need it, for example
uvesafb, so we give them this function to check
and ajust themself.

Signed-off-by Wang YanQing <[email protected]>

---
 arch/x86/include/asm/pci.h |    1 +
 arch/x86/mm/pageattr.c     |    2 +-
 arch/x86/pci/pcbios.c      |   11 +++++++++++
 3 files changed, 13 insertions(+), 1 deletions(-)

arch/x86/include/asm/pci.h +1 -0

index df75d07..31d657b 100644
@@ -66,6 +66,7 @@ extern unsigned long pci_mem_start;
 #define PCIBIOS_MIN_CARDBUS_IO	0x4000
 
 extern int pcibios_enabled;
+extern int check_pcibios_enabled(void);
 void pcibios_config_init(void);
 struct pci_bus *pcibios_scan_root(int bus);

arch/x86/mm/pageattr.c +1 -1

index e1ebde3..b1fb064 100644
@@ -260,7 +260,7 @@ static inline pgprot_t static_protections(pgprot_t prot, unsigned long address,
 	 * PCI BIOS based config access (CONFIG_PCI_GOBIOS) support.
 	 */
 #ifdef CONFIG_PCI_BIOS
-	if (pcibios_enabled && within(pfn, BIOS_BEGIN >> PAGE_SHIFT, BIOS_END >> PAGE_SHIFT))
+	if (check_pcibios_enabled() && within(pfn, BIOS_BEGIN >> PAGE_SHIFT, BIOS_END >> PAGE_SHIFT))
 		pgprot_val(forbidden) |= _PAGE_NX;
 #endif

arch/x86/pci/pcbios.c +11 -0

index da8fe05..86e0674 100644
@@ -28,6 +28,17 @@
 
 int pcibios_enabled;
 
+/*
+  Although we don't want any RWX memory in system,
+  but there are still some may need it, so we give
+  them this function to check and ajust themself.
+*/
+int check_pcibios_enabled()
+{
+	return pcibios_enabled;
+}
+EXPORT_SYMBOL(check_pcibios_enabled);
+
 /* According to the BIOS specification at:
  * http://members.datafast.net.au/dft0802/specs/bios21.pdf, we could
  * restrict the x zone to some pages and make it ro. But this may be

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