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David Gibson883a3e52009-10-26 19:24:31 +00001/*
2 * PPC64 Huge TLB Page Support for hash based MMUs (POWER4 and later)
3 *
4 * Copyright (C) 2003 David Gibson, IBM Corporation.
5 *
6 * Based on the IA-32 version:
7 * Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
8 */
9
10#include <linux/mm.h>
11#include <linux/hugetlb.h>
12#include <asm/pgtable.h>
13#include <asm/pgalloc.h>
14#include <asm/cacheflush.h>
15#include <asm/machdep.h>
16
Li Zhongb170bd32013-04-15 16:53:19 +000017extern long hpte_insert_repeating(unsigned long hash, unsigned long vpn,
18 unsigned long pa, unsigned long rlags,
19 unsigned long vflags, int psize, int ssize);
20
David Gibson883a3e52009-10-26 19:24:31 +000021int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid,
Aneesh Kumar K.Vaefa5682014-12-04 11:00:14 +053022 pte_t *ptep, unsigned long trap, unsigned long flags,
23 int ssize, unsigned int shift, unsigned int mmu_psize)
David Gibson883a3e52009-10-26 19:24:31 +000024{
Aneesh Kumar K.V5524a272012-09-10 02:52:50 +000025 unsigned long vpn;
David Gibson883a3e52009-10-26 19:24:31 +000026 unsigned long old_pte, new_pte;
Aneesh Kumar K.V5524a272012-09-10 02:52:50 +000027 unsigned long rflags, pa, sz;
David Gibson883a3e52009-10-26 19:24:31 +000028 long slot;
David Gibson883a3e52009-10-26 19:24:31 +000029
30 BUG_ON(shift != mmu_psize_defs[mmu_psize].shift);
31
32 /* Search the Linux page table for a match with va */
Aneesh Kumar K.V5524a272012-09-10 02:52:50 +000033 vpn = hpt_vpn(ea, vsid, ssize);
David Gibson883a3e52009-10-26 19:24:31 +000034
Benjamin Herrenschmidt171aa2c2010-07-23 09:02:27 +100035 /* At this point, we have a pte (old_pte) which can be used to build
David Gibson883a3e52009-10-26 19:24:31 +000036 * or update an HPTE. There are 2 cases:
37 *
38 * 1. There is a valid (present) pte with no associated HPTE (this is
39 * the most common case)
40 * 2. There is a valid (present) pte with an associated HPTE. The
41 * current values of the pp bits in the HPTE prevent access
42 * because we are doing software DIRTY bit management and the
43 * page is currently not DIRTY.
44 */
45
46
47 do {
48 old_pte = pte_val(*ptep);
Benjamin Herrenschmidt171aa2c2010-07-23 09:02:27 +100049 /* If PTE busy, retry the access */
50 if (unlikely(old_pte & _PAGE_BUSY))
51 return 0;
52 /* If PTE permissions don't match, take page fault */
53 if (unlikely(access & ~old_pte))
54 return 1;
55 /* Try to lock the PTE, add ACCESSED and DIRTY if it was
56 * a write access */
David Gibson883a3e52009-10-26 19:24:31 +000057 new_pte = old_pte | _PAGE_BUSY | _PAGE_ACCESSED;
Benjamin Herrenschmidt171aa2c2010-07-23 09:02:27 +100058 if (access & _PAGE_RW)
59 new_pte |= _PAGE_DIRTY;
David Gibson883a3e52009-10-26 19:24:31 +000060 } while(old_pte != __cmpxchg_u64((unsigned long *)ptep,
61 old_pte, new_pte));
Aneesh Kumar K.Vc6a3c492015-12-01 09:06:50 +053062 rflags = htab_convert_pte_flags(new_pte);
David Gibson883a3e52009-10-26 19:24:31 +000063
David Gibson883a3e52009-10-26 19:24:31 +000064 sz = ((1UL) << shift);
65 if (!cpu_has_feature(CPU_FTR_COHERENT_ICACHE))
66 /* No CPU has hugepages but lacks no execute, so we
67 * don't need to worry about that case */
David Gibson0895ecd2009-10-26 19:24:31 +000068 rflags = hash_page_do_lazy_icache(rflags, __pte(old_pte), trap);
David Gibson883a3e52009-10-26 19:24:31 +000069
70 /* Check if pte already has an hpte (case 2) */
71 if (unlikely(old_pte & _PAGE_HASHPTE)) {
72 /* There MIGHT be an HPTE for this pte */
73 unsigned long hash, slot;
74
Aneesh Kumar K.V5524a272012-09-10 02:52:50 +000075 hash = hpt_hash(vpn, shift, ssize);
David Gibson883a3e52009-10-26 19:24:31 +000076 if (old_pte & _PAGE_F_SECOND)
77 hash = ~hash;
78 slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
Paul Mackerrasa9d49962016-02-22 13:41:17 +110079 slot += (old_pte & _PAGE_F_GIX) >> _PAGE_F_GIX_SHIFT;
David Gibson883a3e52009-10-26 19:24:31 +000080
Aneesh Kumar K.V5524a272012-09-10 02:52:50 +000081 if (ppc_md.hpte_updatepp(slot, rflags, vpn, mmu_psize,
Aneesh Kumar K.Vaefa5682014-12-04 11:00:14 +053082 mmu_psize, ssize, flags) == -1)
David Gibson883a3e52009-10-26 19:24:31 +000083 old_pte &= ~_PAGE_HPTEFLAGS;
84 }
85
86 if (likely(!(old_pte & _PAGE_HASHPTE))) {
Aneesh Kumar K.V5524a272012-09-10 02:52:50 +000087 unsigned long hash = hpt_hash(vpn, shift, ssize);
David Gibson883a3e52009-10-26 19:24:31 +000088
89 pa = pte_pfn(__pte(old_pte)) << PAGE_SHIFT;
90
David Gibson883a3e52009-10-26 19:24:31 +000091 /* clear HPTE slot informations in new PTE */
David Gibson883a3e52009-10-26 19:24:31 +000092 new_pte = (new_pte & ~_PAGE_HPTEFLAGS) | _PAGE_HASHPTE;
Aneesh Kumar K.Vbf680d52015-12-01 09:06:45 +053093
Li Zhongb170bd32013-04-15 16:53:19 +000094 slot = hpte_insert_repeating(hash, vpn, pa, rflags, 0,
95 mmu_psize, ssize);
David Gibson883a3e52009-10-26 19:24:31 +000096
Anton Blanchardb1623e72010-07-14 19:31:48 +000097 /*
98 * Hypervisor failure. Restore old pte and return -1
99 * similar to __hash_page_*
100 */
101 if (unlikely(slot == -2)) {
102 *ptep = __pte(old_pte);
Benjamin Herrenschmidt4b8692c2010-07-23 10:31:13 +1000103 hash_failure_debug(ea, access, vsid, trap, ssize,
Aneesh Kumar K.Vd8139eb2013-04-28 09:37:37 +0000104 mmu_psize, mmu_psize, old_pte);
Benjamin Herrenschmidt171aa2c2010-07-23 09:02:27 +1000105 return -1;
Anton Blanchardb1623e72010-07-14 19:31:48 +0000106 }
David Gibson883a3e52009-10-26 19:24:31 +0000107
Paul Mackerrasa9d49962016-02-22 13:41:17 +1100108 new_pte |= (slot << _PAGE_F_GIX_SHIFT) &
109 (_PAGE_F_SECOND | _PAGE_F_GIX);
David Gibson883a3e52009-10-26 19:24:31 +0000110 }
111
112 /*
113 * No need to use ldarx/stdcx here
114 */
115 *ptep = __pte(new_pte & ~_PAGE_BUSY);
Benjamin Herrenschmidt171aa2c2010-07-23 09:02:27 +1000116 return 0;
David Gibson883a3e52009-10-26 19:24:31 +0000117}
Aneesh Kumar K.V26a344a2015-12-01 09:06:52 +0530118
119#if defined(CONFIG_PPC_64K_PAGES) && defined(CONFIG_DEBUG_VM)
120/*
121 * This enables us to catch the wrong page directory format
122 * Moved here so that we can use WARN() in the call.
123 */
124int hugepd_ok(hugepd_t hpd)
125{
126 bool is_hugepd;
127
128 /*
129 * We should not find this format in page directory, warn otherwise.
130 */
131 is_hugepd = (((hpd.pd & 0x3) == 0x0) && ((hpd.pd & HUGEPD_SHIFT_MASK) != 0));
132 WARN(is_hugepd, "Found wrong page directory format\n");
133 return 0;
134}
135#endif