From 651060aba79dc9d0cc77ac3921948ea78dba7409 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Tue, 5 Jul 2016 12:17:56 +1000 Subject: [PATCH] target-ppc: Correct page size decoding in ppc_hash64_pteg_search() The architecture specifies that when searching a PTEG for PTEs, entries with a page size encoding that's not valid for the current segment should be ignored, continuing the search. The current implementation does this with ppc_hash64_pte_size_decode() which is a very incomplete implementation of this check. We already have code to do a full and correct page size decode in hpte_page_shift(). This patch moves hpte_page_shift() so it can be used in ppc_hash64_pteg_search() and adjusts the latter's parameters to include a full SLBE instead of just a segment page shift. Signed-off-by: David Gibson Reviewed-by: Benjamin Herrenschmidt --- target-ppc/mmu-hash64.c | 103 +++++++++++++++++----------------------- 1 file changed, 43 insertions(+), 60 deletions(-) diff --git a/target-ppc/mmu-hash64.c b/target-ppc/mmu-hash64.c index a15ef83f7d..6d3428ef7d 100644 --- a/target-ppc/mmu-hash64.c +++ b/target-ppc/mmu-hash64.c @@ -450,30 +450,45 @@ void ppc_hash64_stop_access(PowerPCCPU *cpu, uint64_t token) } } -/* Returns the effective page shift or 0. MPSS isn't supported yet so - * this will always be the slb_pshift or 0 - */ -static uint32_t ppc_hash64_pte_size_decode(uint64_t pte1, uint32_t slb_pshift) +static unsigned hpte_page_shift(const struct ppc_one_seg_page_size *sps, + uint64_t pte0, uint64_t pte1) { - switch (slb_pshift) { - case 12: + int i; + + if (!(pte0 & HPTE64_V_LARGE)) { + if (sps->page_shift != 12) { + /* 4kiB page in a non 4kiB segment */ + return 0; + } + /* Normal 4kiB page */ return 12; - case 16: - if ((pte1 & 0xf000) == 0x1000) { - return 16; - } - return 0; - case 24: - if ((pte1 & 0xff000) == 0) { - return 24; - } - return 0; } - return 0; + + for (i = 0; i < PPC_PAGE_SIZES_MAX_SZ; i++) { + const struct ppc_one_page_size *ps = &sps->enc[i]; + uint64_t mask; + + if (!ps->page_shift) { + break; + } + + if (ps->page_shift == 12) { + /* L bit is set so this can't be a 4kiB page */ + continue; + } + + mask = ((1ULL << ps->page_shift) - 1) & HPTE64_R_RPN; + + if ((pte1 & mask) == (ps->pte_enc << HPTE64_R_RPN_SHIFT)) { + return ps->page_shift; + } + } + + return 0; /* Bad page size encoding */ } static hwaddr ppc_hash64_pteg_search(PowerPCCPU *cpu, hwaddr hash, - uint32_t slb_pshift, bool secondary, + ppc_slb_t *slb, bool secondary, target_ulong ptem, ppc_hash_pte64_t *pte) { CPUPPCState *env = &cpu->env; @@ -494,7 +509,14 @@ static hwaddr ppc_hash64_pteg_search(PowerPCCPU *cpu, hwaddr hash, if ((pte0 & HPTE64_V_VALID) && (secondary == !!(pte0 & HPTE64_V_SECONDARY)) && HPTE64_V_COMPARE(pte0, ptem)) { - uint32_t pshift = ppc_hash64_pte_size_decode(pte1, slb_pshift); + unsigned pshift = hpte_page_shift(slb->sps, pte0, pte1); + /* + * If there is no match, ignore the PTE, it could simply + * be for a different segment size encoding and the + * architecture specifies we should not match. Linux will + * potentially leave behind PTEs for the wrong base page + * size when demoting segments. + */ if (pshift == 0) { continue; } @@ -554,8 +576,7 @@ static hwaddr ppc_hash64_htab_lookup(PowerPCCPU *cpu, " vsid=" TARGET_FMT_lx " ptem=" TARGET_FMT_lx " hash=" TARGET_FMT_plx "\n", env->htab_base, env->htab_mask, vsid, ptem, hash); - pte_offset = ppc_hash64_pteg_search(cpu, hash, slb->sps->page_shift, - 0, ptem, pte); + pte_offset = ppc_hash64_pteg_search(cpu, hash, slb, 0, ptem, pte); if (pte_offset == -1) { /* Secondary PTEG lookup */ @@ -565,50 +586,12 @@ static hwaddr ppc_hash64_htab_lookup(PowerPCCPU *cpu, " hash=" TARGET_FMT_plx "\n", env->htab_base, env->htab_mask, vsid, ptem, ~hash); - pte_offset = ppc_hash64_pteg_search(cpu, ~hash, slb->sps->page_shift, 1, - ptem, pte); + pte_offset = ppc_hash64_pteg_search(cpu, ~hash, slb, 1, ptem, pte); } return pte_offset; } -static unsigned hpte_page_shift(const struct ppc_one_seg_page_size *sps, - uint64_t pte0, uint64_t pte1) -{ - int i; - - if (!(pte0 & HPTE64_V_LARGE)) { - if (sps->page_shift != 12) { - /* 4kiB page in a non 4kiB segment */ - return 0; - } - /* Normal 4kiB page */ - return 12; - } - - for (i = 0; i < PPC_PAGE_SIZES_MAX_SZ; i++) { - const struct ppc_one_page_size *ps = &sps->enc[i]; - uint64_t mask; - - if (!ps->page_shift) { - break; - } - - if (ps->page_shift == 12) { - /* L bit is set so this can't be a 4kiB page */ - continue; - } - - mask = ((1ULL << ps->page_shift) - 1) & HPTE64_R_RPN; - - if ((pte1 & mask) == (ps->pte_enc << HPTE64_R_RPN_SHIFT)) { - return ps->page_shift; - } - } - - return 0; /* Bad page size encoding */ -} - unsigned ppc_hash64_hpte_page_shift_noslb(PowerPCCPU *cpu, uint64_t pte0, uint64_t pte1) {