diff options
Diffstat (limited to 'arch/x86/mm/ioremap.c')
| -rw-r--r-- | arch/x86/mm/ioremap.c | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c index fdf617c00e2f..5ead4d6cf3a7 100644 --- a/arch/x86/mm/ioremap.c +++ b/arch/x86/mm/ioremap.c @@ -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 |