diff options
Diffstat (limited to 'arch/powerpc/mm/hash_utils_64.c')
| -rw-r--r-- | arch/powerpc/mm/hash_utils_64.c | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c index 0821556e16f4..ef3ae891a3db 100644 --- a/arch/powerpc/mm/hash_utils_64.c +++ b/arch/powerpc/mm/hash_utils_64.c @@ -93,6 +93,9 @@ static unsigned long _SDR1; struct mmu_psize_def mmu_psize_defs[MMU_PAGE_COUNT]; EXPORT_SYMBOL_GPL(mmu_psize_defs); +u8 hpte_page_sizes[1 << LP_BITS]; +EXPORT_SYMBOL_GPL(hpte_page_sizes); + struct hash_pte *htab_address; unsigned long htab_size_bytes; unsigned long htab_hash_mask; @@ -564,8 +567,60 @@ static void __init htab_scan_page_sizes(void) #endif /* CONFIG_HUGETLB_PAGE */ } +/* + * Fill in the hpte_page_sizes[] array. + * We go through the mmu_psize_defs[] array looking for all the + * supported base/actual page size combinations. Each combination + * has a unique pagesize encoding (penc) value in the low bits of + * the LP field of the HPTE. For actual page sizes less than 1MB, + * some of the upper LP bits are used for RPN bits, meaning that + * we need to fill in several entries in hpte_page_sizes[]. + * + * In diagrammatic form, with r = RPN bits and z = page size bits: + * PTE LP actual page size + * rrrr rrrz >=8KB + * rrrr rrzz >=16KB + * rrrr rzzz >=32KB + * rrrr zzzz >=64KB + * ... + * + * The zzzz bits are implementation-specific but are chosen so that + * no encoding for a larger page size uses the same value in its + * low-order N bits as the encoding for the 2^(12+N) byte page size + * (if it exists). + */ +static void init_hpte_page_sizes(void) +{ + long int ap, bp; + long int shift, penc; + + for (bp = 0; bp < MMU_PAGE_COUNT; ++bp) { + if (!mmu_psize_defs[bp].shift) + continue; /* not a supported page size */ + for (ap = bp; ap < MMU_PAGE_COUNT; ++ap) { + penc = mmu_psize_defs[bp].penc[ap]; + if (penc == -1) + continue; + shift = mmu_psize_defs[ap].shift - LP_SHIFT; + if (shift <= 0) + continue; /* should never happen */ + /* + * For page sizes less than 1MB, this loop + * replicates the entry for all possible values + * of the rrrr bits. + */ + while (penc < (1 << LP_BITS)) { + hpte_page_sizes[penc] = (ap << 4) | bp; + penc += 1 << shift; + } + } + } +} + static void __init htab_init_page_sizes(void) { + init_hpte_page_sizes(); + if (!debug_pagealloc_enabled()) { /* * Pick a size for the linear mapping. Currently, we only |