[PATCH -V1] x86: make executable for video bios area

wangyanqing
2011-11-15T06:44:06Z

5bd5a452662bc37c54fb6828db1a3faf87e6511c make area
between BIOS_BEGIN and BIOS_END have NX protection
when boot machine with acpi enable(acpi will disable pcibios).

This commit make my machine can't boot, system hang with black screen
very early when I enable CONFIG_FB_UVESA, CONFIG_X86_PAE, CONFIG_ACPI.

below is the maps when boot normal without acpi:
00000000-00001000 rw-s 00000000 00:01 822 /dev/mem
00009000-0000a000 r-xp 00001000 00:01 912 /sbin/v86d
00010000-00050000 rwxp 00000000 00:01 818 /dev/zero
000a0000-000c0000 rw-s 000a0000 00:01 822 /dev/mem
000c0000-00100000 r-xs 000c0000 00:01 822 /dev/mem <== must executable
08048000-0804c000 r-xp 00001000 00:01 912 /sbin/v86d
0804c000-0804d000 rw-p 00004000 00:01 912 /sbin/v86d
b7875000-b7876000 r-xp 00000000 00:00 0 [vdso]
bfe9d000-bfebe000 rw-p 00000000 00:00 0 [stack]

So I prepare this patch.It works with me.
Any comment is welcome.

Thanks.

Signed-off-by: Wang YanQing <Udknight@gmail.com>
---
arch/x86/include/asm/e820.h | 2 ++
arch/x86/mm/pageattr.c | 3 ++-
2 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/arch/x86/include/asm/e820.h b/arch/x86/include/asm/e820.h
index 908b969..a6fa897 100644
--- a/arch/x86/include/asm/e820.h
+++ b/arch/x86/include/asm/e820.h
@@ -72,6 +72,8 @@ struct e820map {
#define BIOS_BEGIN 0x000a0000
#define BIOS_END 0x00100000

+#define BIOS_VIDEO 0x000c0000
+
#define BIOS_ROM_BASE 0xffe00000
#define BIOS_ROM_END 0xffffffff

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index f9e5267..12acac0 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -260,7 +260,8 @@ 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 ((pcibios_enabled || within(pfn, BIOS_VIDEO >> PAGE_SHIFT, BIOS_END >> PAGE_SHIFT)) &&
+ within(pfn, BIOS_BEGIN >> PAGE_SHIFT, BIOS_END >> PAGE_SHIFT))
pgprot_val(forbidden) |= _PAGE_NX;
#endif

--
1.7.3.4