diff options
author | Toshi Kani <toshi.kani@hp.com> | 2015-04-14 15:47:32 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-04-14 16:49:04 -0700 |
commit | 6b6378355b925050eb6fa966742d8c2d65ff0d83 (patch) | |
tree | 34fae2afb71d981d8ef8a2c640836c46781c00b8 /arch/x86/mm/pgtable.c | |
parent | 5d72b4fba40ef4b3f7a1a11d6aacc85d9af81561 (diff) | |
download | op-kernel-dev-6b6378355b925050eb6fa966742d8c2d65ff0d83.zip op-kernel-dev-6b6378355b925050eb6fa966742d8c2d65ff0d83.tar.gz |
x86, mm: support huge KVA mappings on x86
Implement huge KVA mapping interfaces on x86.
On x86, MTRRs can override PAT memory types with a 4KB granularity. When
using a huge page, MTRRs can override the memory type of the huge page,
which may lead a performance penalty. The processor can also behave in an
undefined manner if a huge page is mapped to a memory range that MTRRs
have mapped with multiple different memory types. Therefore, the mapping
code falls back to use a smaller page size toward 4KB when a mapping range
is covered by non-WB type of MTRRs. The WB type of MTRRs has no affect on
the PAT memory types.
pud_set_huge() and pmd_set_huge() call mtrr_type_lookup() to see if a
given range is covered by MTRRs. MTRR_TYPE_WRBACK indicates that the
range is either covered by WB or not covered and the MTRR default value is
set to WB. 0xFF indicates that MTRRs are disabled.
HAVE_ARCH_HUGE_VMAP is selected when X86_64 or X86_32 with X86_PAE is set.
X86_32 without X86_PAE is not supported since such config can unlikey be
benefited from this feature, and there was an issue found in testing.
[fengguang.wu@intel.com: ioremap_pud_capable can be static]
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: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/x86/mm/pgtable.c')
-rw-r--r-- | arch/x86/mm/pgtable.c | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index b28edfe..0b97d2c 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -4,6 +4,7 @@ #include <asm/pgtable.h> #include <asm/tlb.h> #include <asm/fixmap.h> +#include <asm/mtrr.h> #define PGALLOC_GFP GFP_KERNEL | __GFP_NOTRACK | __GFP_REPEAT | __GFP_ZERO @@ -560,3 +561,67 @@ void native_set_fixmap(enum fixed_addresses idx, phys_addr_t phys, { __native_set_fixmap(idx, pfn_pte(phys >> PAGE_SHIFT, flags)); } + +#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP +int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot) +{ + u8 mtrr; + + /* + * Do not use a huge page when the range is covered by non-WB type + * of MTRRs. + */ + mtrr = mtrr_type_lookup(addr, addr + PUD_SIZE); + if ((mtrr != MTRR_TYPE_WRBACK) && (mtrr != 0xFF)) + return 0; + + prot = pgprot_4k_2_large(prot); + + set_pte((pte_t *)pud, pfn_pte( + (u64)addr >> PAGE_SHIFT, + __pgprot(pgprot_val(prot) | _PAGE_PSE))); + + return 1; +} + +int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot) +{ + u8 mtrr; + + /* + * Do not use a huge page when the range is covered by non-WB type + * of MTRRs. + */ + mtrr = mtrr_type_lookup(addr, addr + PMD_SIZE); + if ((mtrr != MTRR_TYPE_WRBACK) && (mtrr != 0xFF)) + return 0; + + prot = pgprot_4k_2_large(prot); + + set_pte((pte_t *)pmd, pfn_pte( + (u64)addr >> PAGE_SHIFT, + __pgprot(pgprot_val(prot) | _PAGE_PSE))); + + return 1; +} + +int pud_clear_huge(pud_t *pud) +{ + if (pud_large(*pud)) { + pud_clear(pud); + return 1; + } + + return 0; +} + +int pmd_clear_huge(pmd_t *pmd) +{ + if (pmd_large(*pmd)) { + pmd_clear(pmd); + return 1; + } + + return 0; +} +#endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */ |