arch/powerpc/mm/hugepage-hash64.c - kernel/msm-4.9 - Gitiles

 /*
  * Copyright IBM Corporation, 2013
  * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of version 2.1 of the GNU Lesser General Public License
  * as published by the Free Software Foundation.
  *
  * This program is distributed in the hope that it would be useful, but
  * WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  *
  */

 /*
  * PPC64 THP Support for hash based MMUs
  */
 #include <linux/mm.h>
 #include <asm/machdep.h>

 static void invalidate_old_hpte(unsigned long vsid, unsigned long addr,
 				pmd_t *pmdp, unsigned int psize, int ssize)
 {
 	int i, max_hpte_count, valid;
 	unsigned long s_addr;
 	unsigned char *hpte_slot_array;
 	unsigned long hidx, shift, vpn, hash, slot;

 	s_addr = addr & HPAGE_PMD_MASK;
 	hpte_slot_array = get_hpte_slot_array(pmdp);
 	/*
 	 * IF we try to do a HUGE PTE update after a withdraw is done.
 	 * we will find the below NULL. This happens when we do
 	 * split_huge_page_pmd
 	 */
 	if (!hpte_slot_array)
 		return;

 	if (ppc_md.hugepage_invalidate)
 		return ppc_md.hugepage_invalidate(vsid, s_addr, hpte_slot_array,
 						  psize, ssize);
 	/*
 	 * No bluk hpte removal support, invalidate each entry
 	 */
 	shift = mmu_psize_defs[psize].shift;
 	max_hpte_count = HPAGE_PMD_SIZE >> shift;
 	for (i = 0; i < max_hpte_count; i++) {
 		/*
 		 * 8 bits per each hpte entries
 		 * 000| [ secondary group (one bit) | hidx (3 bits) | valid bit]
 		 */
 		valid = hpte_valid(hpte_slot_array, i);
 		if (!valid)
 			continue;
 		hidx =  hpte_hash_index(hpte_slot_array, i);

 		/* get the vpn */
 		addr = s_addr + (i * (1ul << shift));
 		vpn = hpt_vpn(addr, vsid, ssize);
 		hash = hpt_hash(vpn, shift, ssize);
 		if (hidx & _PTEIDX_SECONDARY)
 			hash = ~hash;

 		slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
 		slot += hidx & _PTEIDX_GROUP_IX;
 		ppc_md.hpte_invalidate(slot, vpn, psize,
 				       MMU_PAGE_16M, ssize, 0);
 	}
 }


 int __hash_page_thp(unsigned long ea, unsigned long access, unsigned long vsid,
 		    pmd_t *pmdp, unsigned long trap, int local, int ssize,
 		    unsigned int psize)
 {
 	unsigned int index, valid;
 	unsigned char *hpte_slot_array;
 	unsigned long rflags, pa, hidx;
 	unsigned long old_pmd, new_pmd;
 	int ret, lpsize = MMU_PAGE_16M;
 	unsigned long vpn, hash, shift, slot;

 	/*
 	 * atomically mark the linux large page PMD busy and dirty
 	 */
 	do {
 		pmd_t pmd = ACCESS_ONCE(*pmdp);

 		old_pmd = pmd_val(pmd);
 		/* If PMD busy, retry the access */
 		if (unlikely(old_pmd & _PAGE_BUSY))
 			return 0;
 		/* If PMD is trans splitting retry the access */
 		if (unlikely(old_pmd & _PAGE_SPLITTING))
 			return 0;
 		/* If PMD permissions don't match, take page fault */
 		if (unlikely(access & ~old_pmd))
 			return 1;
 		/*
 		 * Try to lock the PTE, add ACCESSED and DIRTY if it was
 		 * a write access
 		 */
 		new_pmd = old_pmd | _PAGE_BUSY | _PAGE_ACCESSED;
 		if (access & _PAGE_RW)
 			new_pmd |= _PAGE_DIRTY;
 	} while (old_pmd != __cmpxchg_u64((unsigned long *)pmdp,
 					  old_pmd, new_pmd));
 	/*
 	 * PP bits. _PAGE_USER is already PP bit 0x2, so we only
 	 * need to add in 0x1 if it's a read-only user page
 	 */
 	rflags = new_pmd & _PAGE_USER;
 	if ((new_pmd & _PAGE_USER) && !((new_pmd & _PAGE_RW) &&
 					   (new_pmd & _PAGE_DIRTY)))
 		rflags |= 0x1;
 	/*
 	 * _PAGE_EXEC -> HW_NO_EXEC since it's inverted
 	 */
 	rflags |= ((new_pmd & _PAGE_EXEC) ? 0 : HPTE_R_N);

 #if 0
 	if (!cpu_has_feature(CPU_FTR_COHERENT_ICACHE)) {

 		/*
 		 * No CPU has hugepages but lacks no execute, so we
 		 * don't need to worry about that case
 		 */
 		rflags = hash_page_do_lazy_icache(rflags, __pte(old_pte), trap);
 	}
 #endif
 	/*
 	 * Find the slot index details for this ea, using base page size.
 	 */
 	shift = mmu_psize_defs[psize].shift;
 	index = (ea & ~HPAGE_PMD_MASK) >> shift;
 	BUG_ON(index >= 4096);

 	vpn = hpt_vpn(ea, vsid, ssize);
 	hash = hpt_hash(vpn, shift, ssize);
 	hpte_slot_array = get_hpte_slot_array(pmdp);
 	if (psize == MMU_PAGE_4K) {
 		/*
 		 * invalidate the old hpte entry if we have that mapped via 64K
 		 * base page size. This is because demote_segment won't flush
 		 * hash page table entries.
 		 */
 		if ((old_pmd & _PAGE_HASHPTE) && !(old_pmd & _PAGE_COMBO))
 			invalidate_old_hpte(vsid, ea, pmdp, MMU_PAGE_64K, ssize);
 	}

 	valid = hpte_valid(hpte_slot_array, index);
 	if (valid) {
 		/* update the hpte bits */
 		hidx =  hpte_hash_index(hpte_slot_array, index);
 		if (hidx & _PTEIDX_SECONDARY)
 			hash = ~hash;
 		slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
 		slot += hidx & _PTEIDX_GROUP_IX;

 		ret = ppc_md.hpte_updatepp(slot, rflags, vpn,
 					   psize, lpsize, ssize, local);
 		/*
 		 * We failed to update, try to insert a new entry.
 		 */
 		if (ret == -1) {
 			/*
 			 * large pte is marked busy, so we can be sure
 			 * nobody is looking at hpte_slot_array. hence we can
 			 * safely update this here.
 			 */
 			valid = 0;
 			hpte_slot_array[index] = 0;
 		}
 	}

 	if (!valid) {
 		unsigned long hpte_group;

 		/* insert new entry */
 		pa = pmd_pfn(__pmd(old_pmd)) << PAGE_SHIFT;
 		new_pmd |= _PAGE_HASHPTE;

 		/* Add in WIMG bits */
 		rflags |= (new_pmd & (_PAGE_WRITETHRU | _PAGE_NO_CACHE |
 				      _PAGE_GUARDED));
 		/*
 		 * enable the memory coherence always
 		 */
 		rflags |= HPTE_R_M;
 repeat:
 		hpte_group = ((hash & htab_hash_mask) * HPTES_PER_GROUP) & ~0x7UL;

 		/* Insert into the hash table, primary slot */
 		slot = ppc_md.hpte_insert(hpte_group, vpn, pa, rflags, 0,
 					  psize, lpsize, ssize);
 		/*
 		 * Primary is full, try the secondary
 		 */
 		if (unlikely(slot == -1)) {
 			hpte_group = ((~hash & htab_hash_mask) *
 				      HPTES_PER_GROUP) & ~0x7UL;
 			slot = ppc_md.hpte_insert(hpte_group, vpn, pa,
 						  rflags, HPTE_V_SECONDARY,
 						  psize, lpsize, ssize);
 			if (slot == -1) {
 				if (mftb() & 0x1)
 					hpte_group = ((hash & htab_hash_mask) *
 						      HPTES_PER_GROUP) & ~0x7UL;

 				ppc_md.hpte_remove(hpte_group);
 				goto repeat;
 			}
 		}
 		/*
 		 * Hypervisor failure. Restore old pmd and return -1
 		 * similar to __hash_page_*
 		 */
 		if (unlikely(slot == -2)) {
 			*pmdp = __pmd(old_pmd);
 			hash_failure_debug(ea, access, vsid, trap, ssize,
 					   psize, lpsize, old_pmd);
 			return -1;
 		}
 		/*
 		 * large pte is marked busy, so we can be sure
 		 * nobody is looking at hpte_slot_array. hence we can
 		 * safely update this here.
 		 */
 		mark_hpte_slot_valid(hpte_slot_array, index, slot);
 	}
 	/*
 	 * Mark the pte with _PAGE_COMBO, if we are trying to hash it with
 	 * base page size 4k.
 	 */
 	if (psize == MMU_PAGE_4K)
 		new_pmd |= _PAGE_COMBO;
 	/*
 	 * The hpte valid is stored in the pgtable whose address is in the
 	 * second half of the PMD. Order this against clearing of the busy bit in
 	 * huge pmd.
 	 */
 	smp_wmb();
 	*pmdp = __pmd(new_pmd & ~_PAGE_BUSY);
 	return 0;
 }
	/*
	* Copyright IBM Corporation, 2013
	* Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
	*
	* This program is free software; you can redistribute it and/or modify it
	* under the terms of version 2.1 of the GNU Lesser General Public License
	* as published by the Free Software Foundation.
	*
	* This program is distributed in the hope that it would be useful, but
	* WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
	*
	*/

	/*
	* PPC64 THP Support for hash based MMUs
	*/
	#include <linux/mm.h>
	#include <asm/machdep.h>

	static void invalidate_old_hpte(unsigned long vsid, unsigned long addr,
	pmd_t *pmdp, unsigned int psize, int ssize)
	{
	int i, max_hpte_count, valid;
	unsigned long s_addr;
	unsigned char *hpte_slot_array;
	unsigned long hidx, shift, vpn, hash, slot;

	s_addr = addr & HPAGE_PMD_MASK;
	hpte_slot_array = get_hpte_slot_array(pmdp);
	/*
	* IF we try to do a HUGE PTE update after a withdraw is done.
	* we will find the below NULL. This happens when we do
	* split_huge_page_pmd
	*/
	if (!hpte_slot_array)
	return;

	if (ppc_md.hugepage_invalidate)
	return ppc_md.hugepage_invalidate(vsid, s_addr, hpte_slot_array,
	psize, ssize);
	/*
	* No bluk hpte removal support, invalidate each entry
	*/
	shift = mmu_psize_defs[psize].shift;
	max_hpte_count = HPAGE_PMD_SIZE >> shift;
	for (i = 0; i < max_hpte_count; i++) {
	/*
	* 8 bits per each hpte entries
	* 000\| [ secondary group (one bit) \| hidx (3 bits) \| valid bit]
	*/
	valid = hpte_valid(hpte_slot_array, i);
	if (!valid)
	continue;
	hidx = hpte_hash_index(hpte_slot_array, i);

	/* get the vpn */
	addr = s_addr + (i * (1ul << shift));
	vpn = hpt_vpn(addr, vsid, ssize);
	hash = hpt_hash(vpn, shift, ssize);
	if (hidx & _PTEIDX_SECONDARY)
	hash = ~hash;

	slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
	slot += hidx & _PTEIDX_GROUP_IX;
	ppc_md.hpte_invalidate(slot, vpn, psize,
	MMU_PAGE_16M, ssize, 0);
	}
	}


	int __hash_page_thp(unsigned long ea, unsigned long access, unsigned long vsid,
	pmd_t *pmdp, unsigned long trap, int local, int ssize,
	unsigned int psize)
	{
	unsigned int index, valid;
	unsigned char *hpte_slot_array;
	unsigned long rflags, pa, hidx;
	unsigned long old_pmd, new_pmd;
	int ret, lpsize = MMU_PAGE_16M;
	unsigned long vpn, hash, shift, slot;

	/*
	* atomically mark the linux large page PMD busy and dirty
	*/
	do {
	pmd_t pmd = ACCESS_ONCE(*pmdp);

	old_pmd = pmd_val(pmd);
	/* If PMD busy, retry the access */
	if (unlikely(old_pmd & _PAGE_BUSY))
	return 0;
	/* If PMD is trans splitting retry the access */
	if (unlikely(old_pmd & _PAGE_SPLITTING))
	return 0;
	/* If PMD permissions don't match, take page fault */
	if (unlikely(access & ~old_pmd))
	return 1;
	/*
	* Try to lock the PTE, add ACCESSED and DIRTY if it was
	* a write access
	*/
	new_pmd = old_pmd \| _PAGE_BUSY \| _PAGE_ACCESSED;
	if (access & _PAGE_RW)
	new_pmd \|= _PAGE_DIRTY;
	} while (old_pmd != __cmpxchg_u64((unsigned long *)pmdp,
	old_pmd, new_pmd));
	/*
	* PP bits. _PAGE_USER is already PP bit 0x2, so we only
	* need to add in 0x1 if it's a read-only user page
	*/
	rflags = new_pmd & _PAGE_USER;
	if ((new_pmd & _PAGE_USER) && !((new_pmd & _PAGE_RW) &&
	(new_pmd & _PAGE_DIRTY)))
	rflags \|= 0x1;
	/*
	* _PAGE_EXEC -> HW_NO_EXEC since it's inverted
	*/
	rflags \|= ((new_pmd & _PAGE_EXEC) ? 0 : HPTE_R_N);

	#if 0
	if (!cpu_has_feature(CPU_FTR_COHERENT_ICACHE)) {

	/*
	* No CPU has hugepages but lacks no execute, so we
	* don't need to worry about that case
	*/
	rflags = hash_page_do_lazy_icache(rflags, __pte(old_pte), trap);
	}
	#endif
	/*
	* Find the slot index details for this ea, using base page size.
	*/
	shift = mmu_psize_defs[psize].shift;
	index = (ea & ~HPAGE_PMD_MASK) >> shift;
	BUG_ON(index >= 4096);

	vpn = hpt_vpn(ea, vsid, ssize);
	hash = hpt_hash(vpn, shift, ssize);
	hpte_slot_array = get_hpte_slot_array(pmdp);
	if (psize == MMU_PAGE_4K) {
	/*
	* invalidate the old hpte entry if we have that mapped via 64K
	* base page size. This is because demote_segment won't flush
	* hash page table entries.
	*/
	if ((old_pmd & _PAGE_HASHPTE) && !(old_pmd & _PAGE_COMBO))
	invalidate_old_hpte(vsid, ea, pmdp, MMU_PAGE_64K, ssize);
	}

	valid = hpte_valid(hpte_slot_array, index);
	if (valid) {
	/* update the hpte bits */
	hidx = hpte_hash_index(hpte_slot_array, index);
	if (hidx & _PTEIDX_SECONDARY)
	hash = ~hash;
	slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
	slot += hidx & _PTEIDX_GROUP_IX;

	ret = ppc_md.hpte_updatepp(slot, rflags, vpn,
	psize, lpsize, ssize, local);
	/*
	* We failed to update, try to insert a new entry.
	*/
	if (ret == -1) {
	/*
	* large pte is marked busy, so we can be sure
	* nobody is looking at hpte_slot_array. hence we can
	* safely update this here.
	*/
	valid = 0;
	hpte_slot_array[index] = 0;
	}
	}

	if (!valid) {
	unsigned long hpte_group;

	/* insert new entry */
	pa = pmd_pfn(__pmd(old_pmd)) << PAGE_SHIFT;
	new_pmd \|= _PAGE_HASHPTE;

	/* Add in WIMG bits */
	rflags \|= (new_pmd & (_PAGE_WRITETHRU \| _PAGE_NO_CACHE \|
	_PAGE_GUARDED));
	/*
	* enable the memory coherence always
	*/
	rflags \|= HPTE_R_M;
	repeat:
	hpte_group = ((hash & htab_hash_mask) * HPTES_PER_GROUP) & ~0x7UL;

	/* Insert into the hash table, primary slot */
	slot = ppc_md.hpte_insert(hpte_group, vpn, pa, rflags, 0,
	psize, lpsize, ssize);
	/*
	* Primary is full, try the secondary
	*/
	if (unlikely(slot == -1)) {
	hpte_group = ((~hash & htab_hash_mask) *
	HPTES_PER_GROUP) & ~0x7UL;
	slot = ppc_md.hpte_insert(hpte_group, vpn, pa,
	rflags, HPTE_V_SECONDARY,
	psize, lpsize, ssize);
	if (slot == -1) {
	if (mftb() & 0x1)
	hpte_group = ((hash & htab_hash_mask) *
	HPTES_PER_GROUP) & ~0x7UL;

	ppc_md.hpte_remove(hpte_group);
	goto repeat;
	}
	}
	/*
	* Hypervisor failure. Restore old pmd and return -1
	* similar to __hash_page_*
	*/
	if (unlikely(slot == -2)) {
	*pmdp = __pmd(old_pmd);
	hash_failure_debug(ea, access, vsid, trap, ssize,
	psize, lpsize, old_pmd);
	return -1;
	}
	/*
	* large pte is marked busy, so we can be sure
	* nobody is looking at hpte_slot_array. hence we can
	* safely update this here.
	*/
	mark_hpte_slot_valid(hpte_slot_array, index, slot);
	}
	/*
	* Mark the pte with _PAGE_COMBO, if we are trying to hash it with
	* base page size 4k.
	*/
	if (psize == MMU_PAGE_4K)
	new_pmd \|= _PAGE_COMBO;
	/*
	* The hpte valid is stored in the pgtable whose address is in the
	* second half of the PMD. Order this against clearing of the busy bit in
	* huge pmd.
	*/
	smp_wmb();
	*pmdp = __pmd(new_pmd & ~_PAGE_BUSY);
	return 0;
	}