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a9d4996df1
This moves the _PAGE_HASHPTE, _PAGE_F_GIX and _PAGE_F_SECOND fields in the Linux PTE on 64-bit Book 3S systems to the most significant byte. Of the 5 bits, one is a software-use bit and the other four are reserved bit positions in the PowerISA v3.0 radix PTE format. Using these bits is OK because these bits are all to do with tracking the HPTE(s) associated with the Linux PTE, and therefore won't be needed in radix mode. This frees up bit positions in the lower two bytes. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
136 lines
3.9 KiB
C
136 lines
3.9 KiB
C
/*
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* PPC64 Huge TLB Page Support for hash based MMUs (POWER4 and later)
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*
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* Copyright (C) 2003 David Gibson, IBM Corporation.
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*
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* Based on the IA-32 version:
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* Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
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*/
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#include <linux/mm.h>
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#include <linux/hugetlb.h>
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#include <asm/pgtable.h>
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#include <asm/pgalloc.h>
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#include <asm/cacheflush.h>
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#include <asm/machdep.h>
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extern long hpte_insert_repeating(unsigned long hash, unsigned long vpn,
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unsigned long pa, unsigned long rlags,
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unsigned long vflags, int psize, int ssize);
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int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid,
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pte_t *ptep, unsigned long trap, unsigned long flags,
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int ssize, unsigned int shift, unsigned int mmu_psize)
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{
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unsigned long vpn;
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unsigned long old_pte, new_pte;
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unsigned long rflags, pa, sz;
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long slot;
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BUG_ON(shift != mmu_psize_defs[mmu_psize].shift);
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/* Search the Linux page table for a match with va */
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vpn = hpt_vpn(ea, vsid, ssize);
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/* At this point, we have a pte (old_pte) which can be used to build
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* or update an HPTE. There are 2 cases:
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*
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* 1. There is a valid (present) pte with no associated HPTE (this is
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* the most common case)
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* 2. There is a valid (present) pte with an associated HPTE. The
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* current values of the pp bits in the HPTE prevent access
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* because we are doing software DIRTY bit management and the
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* page is currently not DIRTY.
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*/
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do {
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old_pte = pte_val(*ptep);
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/* If PTE busy, retry the access */
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if (unlikely(old_pte & _PAGE_BUSY))
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return 0;
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/* If PTE permissions don't match, take page fault */
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if (unlikely(access & ~old_pte))
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return 1;
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/* Try to lock the PTE, add ACCESSED and DIRTY if it was
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* a write access */
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new_pte = old_pte | _PAGE_BUSY | _PAGE_ACCESSED;
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if (access & _PAGE_RW)
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new_pte |= _PAGE_DIRTY;
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} while(old_pte != __cmpxchg_u64((unsigned long *)ptep,
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old_pte, new_pte));
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rflags = htab_convert_pte_flags(new_pte);
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sz = ((1UL) << shift);
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if (!cpu_has_feature(CPU_FTR_COHERENT_ICACHE))
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/* No CPU has hugepages but lacks no execute, so we
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* don't need to worry about that case */
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rflags = hash_page_do_lazy_icache(rflags, __pte(old_pte), trap);
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/* Check if pte already has an hpte (case 2) */
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if (unlikely(old_pte & _PAGE_HASHPTE)) {
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/* There MIGHT be an HPTE for this pte */
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unsigned long hash, slot;
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hash = hpt_hash(vpn, shift, ssize);
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if (old_pte & _PAGE_F_SECOND)
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hash = ~hash;
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slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
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slot += (old_pte & _PAGE_F_GIX) >> _PAGE_F_GIX_SHIFT;
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if (ppc_md.hpte_updatepp(slot, rflags, vpn, mmu_psize,
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mmu_psize, ssize, flags) == -1)
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old_pte &= ~_PAGE_HPTEFLAGS;
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}
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if (likely(!(old_pte & _PAGE_HASHPTE))) {
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unsigned long hash = hpt_hash(vpn, shift, ssize);
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pa = pte_pfn(__pte(old_pte)) << PAGE_SHIFT;
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/* clear HPTE slot informations in new PTE */
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new_pte = (new_pte & ~_PAGE_HPTEFLAGS) | _PAGE_HASHPTE;
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slot = hpte_insert_repeating(hash, vpn, pa, rflags, 0,
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mmu_psize, ssize);
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/*
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* Hypervisor failure. Restore old pte and return -1
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* similar to __hash_page_*
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*/
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if (unlikely(slot == -2)) {
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*ptep = __pte(old_pte);
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hash_failure_debug(ea, access, vsid, trap, ssize,
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mmu_psize, mmu_psize, old_pte);
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return -1;
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}
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new_pte |= (slot << _PAGE_F_GIX_SHIFT) &
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(_PAGE_F_SECOND | _PAGE_F_GIX);
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}
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/*
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* No need to use ldarx/stdcx here
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*/
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*ptep = __pte(new_pte & ~_PAGE_BUSY);
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return 0;
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}
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#if defined(CONFIG_PPC_64K_PAGES) && defined(CONFIG_DEBUG_VM)
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/*
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* This enables us to catch the wrong page directory format
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* Moved here so that we can use WARN() in the call.
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*/
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int hugepd_ok(hugepd_t hpd)
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{
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bool is_hugepd;
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/*
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* We should not find this format in page directory, warn otherwise.
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*/
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is_hugepd = (((hpd.pd & 0x3) == 0x0) && ((hpd.pd & HUGEPD_SHIFT_MASK) != 0));
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WARN(is_hugepd, "Found wrong page directory format\n");
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return 0;
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}
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#endif
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