1. 24 Jul, 2014 2 commits
    • Steven Capper's avatar
      ARM: 8109/1: mm: Modify pte_write and pmd_write logic for LPAE · ded94779
      Steven Capper authored
      For LPAE, we have the following means for encoding writable or dirty
      ptes:
                                    L_PTE_DIRTY       L_PTE_RDONLY
          !pte_dirty && !pte_write        0               1
          !pte_dirty && pte_write         0               1
          pte_dirty && !pte_write         1               1
          pte_dirty && pte_write          1               0
      
      So we can't distinguish between writeable clean ptes and read only
      ptes. This can cause problems with ptes being incorrectly flagged as
      read only when they are writeable but not dirty.
      
      This patch renumbers L_PTE_RDONLY from AP[2] to a software bit #58,
      and adds additional logic to set AP[2] whenever the pte is read only
      or not dirty. That way we can distinguish between clean writeable ptes
      and read only ptes.
      
      HugeTLB pages will use this new logic automatically.
      
      We need to add some logic to Transparent HugePages to ensure that they
      correctly interpret the revised pgprot permissions (L_PTE_RDONLY has
      moved and no longer matches PMD_SECT_AP2). In the process of revising
      THP, the names of the PMD software bits have been prefixed with L_ to
      make them easier to distinguish from their hardware bit counterparts.
      Signed-off-by: default avatarSteve Capper <steve.capper@linaro.org>
      Reviewed-by: default avatarWill Deacon <will.deacon@arm.com>
      Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
      ded94779
    • Steven Capper's avatar
      ARM: 8108/1: mm: Introduce {pte,pmd}_isset and {pte,pmd}_isclear · f2950706
      Steven Capper authored
      Long descriptors on ARM are 64 bits, and some pte functions such as
      pte_dirty return a bitwise-and of a flag with the pte value. If the
      flag to be tested resides in the upper 32 bits of the pte, then we run
      into the danger of the result being dropped if downcast.
      
      For example:
      	gather_stats(page, md, pte_dirty(*pte), 1);
      where pte_dirty(*pte) is downcast to an int.
      
      This patch introduces a new macro pte_isset which performs the bitwise
      and, then performs a double logical invert (where needed) to ensure
      predictable downcasting. The logical inverse pte_isclear is also
      introduced.
      
      Equivalent pmd functions for Transparent HugePages have also been
      added.
      Signed-off-by: default avatarSteve Capper <steve.capper@linaro.org>
      Reviewed-by: default avatarWill Deacon <will.deacon@arm.com>
      Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
      f2950706
  2. 18 Jul, 2014 23 commits
  3. 01 Jul, 2014 4 commits
  4. 29 Jun, 2014 10 commits
  5. 28 Jun, 2014 1 commit