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Commit 5d72b4fb authored by Toshi Kani's avatar Toshi Kani Committed by Linus Torvalds
Browse files

x86, mm: support huge I/O mapping capability I/F 



Implement huge I/O mapping capability interfaces for ioremap() on x86.

IOREMAP_MAX_ORDER is defined to PUD_SHIFT on x86/64 and PMD_SHIFT on
x86/32, which overrides the default value defined in <linux/vmalloc.h>.

Signed-off-by: default avatarToshi Kani <toshi.kani@hp.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Robert Elliott <Elliott@hp.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent b9820d8f

arch/x86/include/asm/page_types.h

+2 −0
Original line number Diff line number Diff line
@@ -40,8 +40,10 @@ 


#ifdef CONFIG_X86_64

#include <asm/page_64_types.h>

#define IOREMAP_MAX_ORDER       (PUD_SHIFT)

#else

#include <asm/page_32_types.h>

#define IOREMAP_MAX_ORDER       (PMD_SHIFT)

#endif	/* CONFIG_X86_64 */



#ifndef __ASSEMBLY__

arch/x86/mm/ioremap.c

+21 −2
Original line number Diff line number Diff line
@@ -67,8 +67,13 @@ static int __ioremap_check_ram(unsigned long start_pfn, unsigned long nr_pages, 


/*

 * Remap an arbitrary physical address space into the kernel virtual

 * address space. Needed when the kernel wants to access high addresses

 * directly.

 * address space. It transparently creates kernel huge I/O mapping when

 * the physical address is aligned by a huge page size (1GB or 2MB) and

 * the requested size is at least the huge page size.

 *

 * NOTE: MTRRs can override PAT memory types with a 4KB granularity.

 * Therefore, the mapping code falls back to use a smaller page toward 4KB

 * when a mapping range is covered by non-WB type of MTRRs.

 *

 * NOTE! We need to allow non-page-aligned mappings too: we will obviously

 * have to convert them into an offset in a page-aligned mapping, but the
@@ -326,6 +331,20 @@ void iounmap(volatile void __iomem *addr) 
}

EXPORT_SYMBOL(iounmap);



int arch_ioremap_pud_supported(void)

{

#ifdef CONFIG_X86_64

	return cpu_has_gbpages;

#else

	return 0;

#endif

}



int arch_ioremap_pmd_supported(void)

{

	return cpu_has_pse;

}



/*

 * Convert a physical pointer to a virtual kernel pointer for /dev/mem

 * access