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: 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>
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@ -40,8 +40,10 @@
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#ifdef CONFIG_X86_64
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#include <asm/page_64_types.h>
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#define IOREMAP_MAX_ORDER (PUD_SHIFT)
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#else
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#include <asm/page_32_types.h>
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#define IOREMAP_MAX_ORDER (PMD_SHIFT)
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#endif /* CONFIG_X86_64 */
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#ifndef __ASSEMBLY__
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@ -67,8 +67,13 @@ static int __ioremap_check_ram(unsigned long start_pfn, unsigned long nr_pages,
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/*
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* Remap an arbitrary physical address space into the kernel virtual
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* address space. Needed when the kernel wants to access high addresses
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* directly.
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* address space. It transparently creates kernel huge I/O mapping when
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* the physical address is aligned by a huge page size (1GB or 2MB) and
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* the requested size is at least the huge page size.
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*
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* NOTE: MTRRs can override PAT memory types with a 4KB granularity.
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* Therefore, the mapping code falls back to use a smaller page toward 4KB
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* when a mapping range is covered by non-WB type of MTRRs.
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*
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* NOTE! We need to allow non-page-aligned mappings too: we will obviously
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* have to convert them into an offset in a page-aligned mapping, but the
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@ -326,6 +331,20 @@ void iounmap(volatile void __iomem *addr)
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}
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EXPORT_SYMBOL(iounmap);
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int arch_ioremap_pud_supported(void)
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{
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#ifdef CONFIG_X86_64
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return cpu_has_gbpages;
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#else
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return 0;
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#endif
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}
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int arch_ioremap_pmd_supported(void)
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{
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return cpu_has_pse;
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}
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/*
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* Convert a physical pointer to a virtual kernel pointer for /dev/mem
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* access
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