[PATCH -V5 09/25] powerpc: Fix hpte_decode to use the correct decoding for page sizes
From: Aneesh Kumar K.V <hidden>
Date: 2013-04-04 05:58:24
Also in:
linux-mm
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Linus Torvalds
From: "Aneesh Kumar K.V" <redacted> As per ISA doc, we encode base and actual page size in the LP bits of PTE. The number of bit used to encode the page sizes depend on actual page size. ISA doc lists this as PTE LP actual page size rrrr rrrz >=8KB rrrr rrzz >=16KB rrrr rzzz >=32KB rrrr zzzz >=64KB rrrz zzzz >=128KB rrzz zzzz >=256KB rzzz zzzz >=512KB zzzz zzzz >=1MB ISA doc also says "The values of the “z” bits used to specify each size, along with all possible values of “r” bits in the LP field, must result in LP values distinct from other LP values for other sizes." based on the above update hpte_decode to use the correct decoding for LP bits. Acked-by: Paul Mackerras <redacted> Signed-off-by: Aneesh Kumar K.V <redacted> --- arch/powerpc/mm/hash_native_64.c | 38 ++++++++++++++++++++++++-------------- 1 file changed, 24 insertions(+), 14 deletions(-)
diff --git a/arch/powerpc/mm/hash_native_64.c b/arch/powerpc/mm/hash_native_64.c
index aa0499b..b461b2d 100644
--- a/arch/powerpc/mm/hash_native_64.c
+++ b/arch/powerpc/mm/hash_native_64.c@@ -428,41 +428,51 @@ static void hpte_decode(struct hash_pte *hpte, unsigned long slot, int *psize, int *apsize, int *ssize, unsigned long *vpn) { unsigned long avpn, pteg, vpi; - unsigned long hpte_r = hpte->r; unsigned long hpte_v = hpte->v; unsigned long vsid, seg_off; - int i, size, a_size, shift, penc; + int size, a_size, shift, mask; + /* Look at the 8 bit LP value */ + unsigned int lp = (hpte->r >> LP_SHIFT) & ((1 << LP_BITS) - 1); if (!(hpte_v & HPTE_V_LARGE)) { size = MMU_PAGE_4K; a_size = MMU_PAGE_4K; } else { - for (i = 0; i < LP_BITS; i++) { - if ((hpte_r & LP_MASK(i+1)) == LP_MASK(i+1)) - break; - } - penc = LP_MASK(i+1) >> LP_SHIFT; for (size = 0; size < MMU_PAGE_COUNT; size++) { /* valid entries have a shift value */ if (!mmu_psize_defs[size].shift) continue; - for (a_size = 0; a_size < MMU_PAGE_COUNT; a_size++) { - - /* 4K pages are not represented by LP */ - if (a_size == MMU_PAGE_4K) - continue; + /* start from 1 ignoring MMU_PAGE_4K */ + for (a_size = 1; a_size < MMU_PAGE_COUNT; a_size++) { /* valid entries have a shift value */ if (!mmu_psize_defs[a_size].shift) continue; - if (penc == mmu_psize_defs[size].penc[a_size]) + /* invalid penc */ + if (mmu_psize_defs[size].penc[a_size] == -1) + continue; + /* + * encoding bits per actual page size + * PTE LP actual page size + * rrrr rrrz >=8KB + * rrrr rrzz >=16KB + * rrrr rzzz >=32KB + * rrrr zzzz >=64KB + * ....... + */ + shift = mmu_psize_defs[a_size].shift - LP_SHIFT; + if (shift > LP_BITS) + shift = LP_BITS; + mask = (1 << shift) - 1; + if ((lp & mask) == + mmu_psize_defs[size].penc[a_size]) { goto out; + } } } } - out: /* This works for all page sizes, and for 256M and 1T segments */ *ssize = hpte_v >> HPTE_V_SSIZE_SHIFT;
--
1.7.10