On 12/27/2016 02:53 AM, Kirill A. Shutemov wrote:
We are going to switch core MM to 5-level paging abstraction. This is preparation step which adds <asm-generic/5level-fixup.h> As with 4level-fixup.h, the new header allows quickly make all architectures compatible with 5-level paging in core MM. In long run we would like to switch architectures to properly folded p4d level by using <asm-generic/pgtable-nop4d.h>, but it requires more changes to arch-specific code. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> --- include/asm-generic/4level-fixup.h | 3 ++- include/asm-generic/5level-fixup.h | 41 ++++++++++++++++++++++++++++++++++++++ include/linux/mm.h | 3 +++ 3 files changed, 46 insertions(+), 1 deletion(-) create mode 100644 include/asm-generic/5level-fixup.h diff --git a/include/asm-generic/4level-fixup.h b/include/asm-generic/4level-fixup.h index 5bdab6bffd23..928fd66b1271 100644 --- a/include/asm-generic/4level-fixup.h +++ b/include/asm-generic/4level-fixup.h @@ -15,7 +15,6 @@ ((unlikely(pgd_none(*(pud))) && __pmd_alloc(mm, pud, address))? \ NULL: pmd_offset(pud, address)) -#define pud_alloc(mm, pgd, address) (pgd)
This...
#define pud_offset(pgd, start) (pgd) #define pud_none(pud) 0 #define pud_bad(pud) 0 @@ -35,4 +34,6 @@ #undef pud_addr_end #define pud_addr_end(addr, end) (end) +#include <asm-generic/5level-fixup.h>
... plus this...
+ #endif diff --git a/include/asm-generic/5level-fixup.h b/include/asm-generic/5level-fixup.h new file mode 100644 index 000000000000..b5ca82dc4175 --- /dev/null +++ b/include/asm-generic/5level-fixup.h @@ -0,0 +1,41 @@ +#ifndef _5LEVEL_FIXUP_H +#define _5LEVEL_FIXUP_H + +#define __ARCH_HAS_5LEVEL_HACK +#define __PAGETABLE_P4D_FOLDED + +#define P4D_SHIFT PGDIR_SHIFT +#define P4D_SIZE PGDIR_SIZE +#define P4D_MASK PGDIR_MASK +#define PTRS_PER_P4D 1 + +#define p4d_t pgd_t + +#define pud_alloc(mm, p4d, address) \ + ((unlikely(pgd_none(*(p4d))) && __pud_alloc(mm, p4d, address)) ? \ + NULL : pud_offset(p4d, address))
... and this, makes me wonder if that broke pud_alloc() for architectures that use the 4level-fixup.h. Don't those need to continue having pud_alloc() as (pgd)?
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