* [PATCH -V1] x86: make executable for video bios area
@ 2011-11-15 6:42 wangyanqing
2011-11-16 3:00 ` wangyanqing
2011-11-16 9:32 ` wangyanqing
0 siblings, 2 replies; 3+ messages in thread
From: wangyanqing @ 2011-11-15 6:42 UTC (permalink / raw)
To: linux-kernel; +Cc: castet.matthieu, torvalds, akpm, gregkh
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
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH -V1] x86: make executable for video bios area
2011-11-15 6:42 [PATCH -V1] x86: make executable for video bios area wangyanqing
@ 2011-11-16 3:00 ` wangyanqing
2011-11-16 9:32 ` wangyanqing
1 sibling, 0 replies; 3+ messages in thread
From: wangyanqing @ 2011-11-16 3:00 UTC (permalink / raw)
To: torvalds; +Cc: linux-kernel, akpm, castet.matthieu, x86
On Tue, Nov 15, 2011 at 02:42:37PM +0800, wangyanqing wrote:
> 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
>
This issue also imply another question.
mmap on /dev/mem haven't check whether the target area can mmap with the request privilege.
Any comments? Linus
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH -V1] x86: make executable for video bios area
2011-11-15 6:42 [PATCH -V1] x86: make executable for video bios area wangyanqing
2011-11-16 3:00 ` wangyanqing
@ 2011-11-16 9:32 ` wangyanqing
1 sibling, 0 replies; 3+ messages in thread
From: wangyanqing @ 2011-11-16 9:32 UTC (permalink / raw)
To: linux-kernel
Cc: castet.matthieu, torvalds, akpm, gregkh, tglx, mingo, hpa, spock
Hi All!
Here is the result of my research, hope it is useful to resolve this question.
Notice:trace from up to down
1:pci_arch_init()
2:pci_mmcfg_early_init() ;boot without PCI_PROBE_NOEARLY
3:__pci_mmcfg_init(1);
4:pci_mmcfg_arch_init(); mmcfg need acpi
5:pci_probe = (pci_probe & ~PCI_PROBE_MASK) | PCI_PROBE_MMCONF; <== IMPORTANT: clean PCI_PROBE_BIOS away
6:pci_pcbios_init();
7:pci_probe & PCI_PROBE_BIOS ; it will fail
8:pci_find_bios() will no chance to execute
the result is:
1:pcibios_enabled will always 0
2:set_bios_x will no chance to execute, so from BIOS_BEGIN to BIOS_END is NX
lrmi:linux real mode interface project, http://sourceforge.net/projects/lrmi/
v86d use lrmi
lrmi.c:358
if (!map_file((void *)0xc0000, 0x40000,
PROT_READ | PROT_EXEC,
MAP_FIXED | MAP_SHARED, "/dev/mem", 0xc0000)) {
munmap((void *)0, 0x502);
munmap((void *)0xa0000, 0x20000);
real_mem_deinit();
return 0;
}
this function to map 000c0000-00100000 with X privilege
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
08048000-0804c000 r-xp 00001000 00:01 912 /sbin/v86d
0804c000-0804d000 rw-p 00004000 00:01 912 /sbin/v86d
b779a000-b779b000 r-xp 00000000 00:00 0 [vdso]
bfac2000-bfae3000 rw-p 00000000 00:00 0 [stack]
At last we get the reason that my machine hang with black screen
The reason is when I boot with ACPI, BIOS_BEGIN to BIOS_END is NX,
then v86d try to map 0xc0000 to 0x100000 with executable privilege,
it mmap success(mem.c:300, mmap_mem haven't check whether it is illegal),
but the pages between BIOS_BEGIN and BIOS_END is NX at all, so it hang!
Question:
1:boot with ACPI make BIOS area NX on X86, is that what we want?
2:mmap_mem haven't check whether it is illegal the mmap target address, right?
Thanks
^ permalink raw reply [flat|nested] 3+ messages in thread
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2011-11-15 6:42 [PATCH -V1] x86: make executable for video bios area wangyanqing
2011-11-16 3:00 ` wangyanqing
2011-11-16 9:32 ` wangyanqing
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