diff options
| -rw-r--r-- | include/asm-ppc/pgtable.h | 26 |
1 files changed, 13 insertions, 13 deletions
diff --git a/include/asm-ppc/pgtable.h b/include/asm-ppc/pgtable.h index c41c7958ea1..92f30b28b25 100644 --- a/include/asm-ppc/pgtable.h +++ b/include/asm-ppc/pgtable.h @@ -227,21 +227,21 @@ extern unsigned long ioremap_bot, ioremap_base; * doesn't support SMP. So we can use this as software bit, like * DIRTY. * - * PPC Book-E Linux implementation uses PPC HW PTE bit field definition, - * even it doesn't have HW PTE. 0-11th LSB of PTE stand for memory - * protection-related function. (See PTE structure in include/asm-ppc/mmu.h) - * Definition of _PAGE_XXX in "include/asm-ppc/pagetable.h" stands for - * above bits. Note that those bits values are CPU dependent, not - * architecture. + * With the PPC 44x Linux implementation, the 0-11th LSBs of the PTE are used + * for memory protection related functions (see PTE structure in + * include/asm-ppc/mmu.h). The _PAGE_XXX definitions in this file map to the + * above bits. Note that the bit values are CPU specific, not architecture + * specific. * - * Kernel PTE entry holds arch-dependent swp_entry structure under certain - * situation. In other words, in such situation, some portion of PTE bits - * are used as swp_entry. In PPC implementation, 3-24th LSB are shared with - * swp_entry, however 0-2nd three LSB still hold protection values. - * That means three protection bits are reserved for both PTE and SWAP - * entry at the most three LSBs. + * The kernel PTE entry holds an arch-dependent swp_entry structure under + * certain situations. In other words, in such situations some portion of + * the PTE bits are used as a swp_entry. In the PPC implementation, the + * 3-24th LSB are shared with swp_entry, however the 0-2nd three LSB still + * hold protection values. That means the three protection bits are + * reserved for both PTE and SWAP entry at the most significant three + * LSBs. * - * There are three protection bits available for SWAP entry; + * There are three protection bits available for SWAP entry: * _PAGE_PRESENT * _PAGE_FILE * _PAGE_HASHPTE (if HW has) |