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

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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: Toshi 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Toshi Kani 2015-04-14 15:47:29 -07:00 committed by Linus Torvalds
parent b9820d8f39
commit 5d72b4fba4
2 changed files with 23 additions and 2 deletions
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2
arch/x86/include/asm/page_types.h
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@ -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__

23
arch/x86/mm/ioremap.c
View File

@ -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