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Commit be43d728 authored by Jeremy Fitzhardinge's avatar Jeremy Fitzhardinge Committed by Ingo Molnar
Browse files

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: default avatarJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 07bb2f62

arch/x86/mm/init_32.c

+1 −1
Original line number Diff line number Diff line
@@ -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

arch/x86/mm/init_64.c

+1 −1
Original line number Diff line number Diff line
@@ -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;

arch/x86/mm/ioremap.c

+4 −4
Original line number Diff line number Diff line
@@ -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;

	}

include/asm-x86/pgtable.h

+12 −2
Original line number Diff line number Diff line
@@ -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