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x86: add _PAGE_IOMAP pte flag for IO mappings 

Use one of the software-defined PTE bits to indicate that a mapping is
intended for an IO address.  On native hardware this is irrelevent,
since a physical address is a physical address.  But in a virtual
environment, physical addresses are also virtualized, so there needs
to be some way to distinguish between pseudo-physical addresses and
actual hardware addresses; _PAGE_IOMAP indicates this intent.

By default, __supported_pte_mask masks out _PAGE_IOMAP, so it doesn't
even appear in the final pagetable.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Jeremy Fitzhardinge 2008-09-07 15:21:13 -07:00 committed by Ingo Molnar
parent 07bb2f6236
commit be43d72835
4 changed files with 18 additions and 8 deletions
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2
arch/x86/mm/init_32.c
View File

@ -558,7 +558,7 @@ void zap_low_mappings(void)
int nx_enabled;
pteval_t __supported_pte_mask __read_mostly = ~(_PAGE_NX | _PAGE_GLOBAL);
pteval_t __supported_pte_mask __read_mostly = ~(_PAGE_NX | _PAGE_GLOBAL | _PAGE_IOMAP);
EXPORT_SYMBOL_GPL(__supported_pte_mask);
#ifdef CONFIG_X86_PAE

2
arch/x86/mm/init_64.c
View File

@ -89,7 +89,7 @@ early_param("gbpages", parse_direct_gbpages_on);
int after_bootmem;
unsigned long __supported_pte_mask __read_mostly = ~0UL;
pteval_t __supported_pte_mask __read_mostly = ~_PAGE_IOMAP;
EXPORT_SYMBOL_GPL(__supported_pte_mask);
static int do_not_nx __cpuinitdata;

8
arch/x86/mm/ioremap.c
View File

@ -242,16 +242,16 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
switch (prot_val) {
case _PAGE_CACHE_UC:
default:
prot = PAGE_KERNEL_NOCACHE;
prot = PAGE_KERNEL_IO_NOCACHE;
break;
case _PAGE_CACHE_UC_MINUS:
prot = PAGE_KERNEL_UC_MINUS;
prot = PAGE_KERNEL_IO_UC_MINUS;
break;
case _PAGE_CACHE_WC:
prot = PAGE_KERNEL_WC;
prot = PAGE_KERNEL_IO_WC;
break;
case _PAGE_CACHE_WB:
prot = PAGE_KERNEL;
prot = PAGE_KERNEL_IO;
break;
}

14
include/asm-x86/pgtable.h
View File

@ -15,7 +15,7 @@
#define _PAGE_BIT_PAT 7 /* on 4KB pages */
#define _PAGE_BIT_GLOBAL 8 /* Global TLB entry PPro+ */
#define _PAGE_BIT_UNUSED1 9 /* available for programmer */
#define _PAGE_BIT_UNUSED2 10
#define _PAGE_BIT_IOMAP 10 /* flag used to indicate IO mapping */
#define _PAGE_BIT_UNUSED3 11
#define _PAGE_BIT_PAT_LARGE 12 /* On 2MB or 1GB pages */
#define _PAGE_BIT_SPECIAL _PAGE_BIT_UNUSED1
@ -32,7 +32,7 @@
#define _PAGE_PSE (_AT(pteval_t, 1) << _PAGE_BIT_PSE)
#define _PAGE_GLOBAL (_AT(pteval_t, 1) << _PAGE_BIT_GLOBAL)
#define _PAGE_UNUSED1 (_AT(pteval_t, 1) << _PAGE_BIT_UNUSED1)
#define _PAGE_UNUSED2 (_AT(pteval_t, 1) << _PAGE_BIT_UNUSED2)
#define _PAGE_IOMAP (_AT(pteval_t, 1) << _PAGE_BIT_IOMAP)
#define _PAGE_UNUSED3 (_AT(pteval_t, 1) << _PAGE_BIT_UNUSED3)
#define _PAGE_PAT (_AT(pteval_t, 1) << _PAGE_BIT_PAT)
#define _PAGE_PAT_LARGE (_AT(pteval_t, 1) << _PAGE_BIT_PAT_LARGE)
@ -99,6 +99,11 @@
#define __PAGE_KERNEL_LARGE_NOCACHE (__PAGE_KERNEL | _PAGE_CACHE_UC | _PAGE_PSE)
#define __PAGE_KERNEL_LARGE_EXEC (__PAGE_KERNEL_EXEC | _PAGE_PSE)
#define __PAGE_KERNEL_IO (__PAGE_KERNEL | _PAGE_IOMAP)
#define __PAGE_KERNEL_IO_NOCACHE (__PAGE_KERNEL_NOCACHE | _PAGE_IOMAP)
#define __PAGE_KERNEL_IO_UC_MINUS (__PAGE_KERNEL_UC_MINUS | _PAGE_IOMAP)
#define __PAGE_KERNEL_IO_WC (__PAGE_KERNEL_WC | _PAGE_IOMAP)
#define PAGE_KERNEL __pgprot(__PAGE_KERNEL)
#define PAGE_KERNEL_RO __pgprot(__PAGE_KERNEL_RO)
#define PAGE_KERNEL_EXEC __pgprot(__PAGE_KERNEL_EXEC)
@ -113,6 +118,11 @@
#define PAGE_KERNEL_VSYSCALL __pgprot(__PAGE_KERNEL_VSYSCALL)
#define PAGE_KERNEL_VSYSCALL_NOCACHE __pgprot(__PAGE_KERNEL_VSYSCALL_NOCACHE)
#define PAGE_KERNEL_IO __pgprot(__PAGE_KERNEL_IO)
#define PAGE_KERNEL_IO_NOCACHE __pgprot(__PAGE_KERNEL_IO_NOCACHE)
#define PAGE_KERNEL_IO_UC_MINUS __pgprot(__PAGE_KERNEL_IO_UC_MINUS)
#define PAGE_KERNEL_IO_WC __pgprot(__PAGE_KERNEL_IO_WC)
/* xwr */
#define __P000 PAGE_NONE
#define __P001 PAGE_READONLY