arch/powerpc/mm/tlb_64.c - kernel/msm-4.19 - Gitiles

 /*
  * This file contains the routines for flushing entries from the
  * TLB and MMU hash table.
  *
  *  Derived from arch/ppc64/mm/init.c:
  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
  *
  *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
  *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
  *    Copyright (C) 1996 Paul Mackerras
  *
  *  Derived from "arch/i386/mm/init.c"
  *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
  *
  *  Dave Engebretsen <engebret@us.ibm.com>
  *      Rework for PPC64 port.
  *
  *  This program is free software; you can redistribute it and/or
  *  modify it under the terms of the GNU General Public License
  *  as published by the Free Software Foundation; either version
  *  2 of the License, or (at your option) any later version.
  */

 #include <linux/kernel.h>
 #include <linux/mm.h>
 #include <linux/init.h>
 #include <linux/percpu.h>
 #include <linux/hardirq.h>
 #include <asm/pgalloc.h>
 #include <asm/tlbflush.h>
 #include <asm/tlb.h>
 #include <asm/bug.h>

 DEFINE_PER_CPU(struct ppc64_tlb_batch, ppc64_tlb_batch);

 /* This is declared as we are using the more or less generic
  * arch/powerpc/include/asm/tlb.h file -- tgall
  */
 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
 static DEFINE_PER_CPU(struct pte_freelist_batch *, pte_freelist_cur);
 static unsigned long pte_freelist_forced_free;

 struct pte_freelist_batch
 {
 	struct rcu_head	rcu;
 	unsigned int	index;
 	pgtable_free_t	tables[0];
 };

 #define PTE_FREELIST_SIZE \
 	((PAGE_SIZE - sizeof(struct pte_freelist_batch)) \
 	  / sizeof(pgtable_free_t))

 static void pte_free_smp_sync(void *arg)
 {
 	/* Do nothing, just ensure we sync with all CPUs */
 }

 /* This is only called when we are critically out of memory
  * (and fail to get a page in pte_free_tlb).
  */
 static void pgtable_free_now(pgtable_free_t pgf)
 {
 	pte_freelist_forced_free++;

 	smp_call_function(pte_free_smp_sync, NULL, 1);

 	pgtable_free(pgf);
 }

 static void pte_free_rcu_callback(struct rcu_head *head)
 {
 	struct pte_freelist_batch *batch =
 		container_of(head, struct pte_freelist_batch, rcu);
 	unsigned int i;

 	for (i = 0; i < batch->index; i++)
 		pgtable_free(batch->tables[i]);

 	free_page((unsigned long)batch);
 }

 static void pte_free_submit(struct pte_freelist_batch *batch)
 {
 	INIT_RCU_HEAD(&batch->rcu);
 	call_rcu(&batch->rcu, pte_free_rcu_callback);
 }

 void pgtable_free_tlb(struct mmu_gather *tlb, pgtable_free_t pgf)
 {
 	/* This is safe since tlb_gather_mmu has disabled preemption */
         cpumask_t local_cpumask = cpumask_of_cpu(smp_processor_id());
 	struct pte_freelist_batch **batchp = &__get_cpu_var(pte_freelist_cur);

 	if (atomic_read(&tlb->mm->mm_users) < 2 ||
 	    cpus_equal(tlb->mm->cpu_vm_mask, local_cpumask)) {
 		pgtable_free(pgf);
 		return;
 	}

 	if (*batchp == NULL) {
 		*batchp = (struct pte_freelist_batch *)__get_free_page(GFP_ATOMIC);
 		if (*batchp == NULL) {
 			pgtable_free_now(pgf);
 			return;
 		}
 		(*batchp)->index = 0;
 	}
 	(*batchp)->tables[(*batchp)->index++] = pgf;
 	if ((*batchp)->index == PTE_FREELIST_SIZE) {
 		pte_free_submit(*batchp);
 		*batchp = NULL;
 	}
 }

 /*
  * A linux PTE was changed and the corresponding hash table entry
  * neesd to be flushed. This function will either perform the flush
  * immediately or will batch it up if the current CPU has an active
  * batch on it.
  *
  * Must be called from within some kind of spinlock/non-preempt region...
  */
 void hpte_need_flush(struct mm_struct *mm, unsigned long addr,
 		     pte_t *ptep, unsigned long pte, int huge)
 {
 	struct ppc64_tlb_batch *batch = &__get_cpu_var(ppc64_tlb_batch);
 	unsigned long vsid, vaddr;
 	unsigned int psize;
 	int ssize;
 	real_pte_t rpte;
 	int i;

 	i = batch->index;

 	/* We mask the address for the base page size. Huge pages will
 	 * have applied their own masking already
 	 */
 	addr &= PAGE_MASK;

 	/* Get page size (maybe move back to caller).
 	 *
 	 * NOTE: when using special 64K mappings in 4K environment like
 	 * for SPEs, we obtain the page size from the slice, which thus
 	 * must still exist (and thus the VMA not reused) at the time
 	 * of this call
 	 */
 	if (huge) {
 #ifdef CONFIG_HUGETLB_PAGE
 		psize = get_slice_psize(mm, addr);;
 #else
 		BUG();
 		psize = pte_pagesize_index(mm, addr, pte); /* shutup gcc */
 #endif
 	} else
 		psize = pte_pagesize_index(mm, addr, pte);

 	/* Build full vaddr */
 	if (!is_kernel_addr(addr)) {
 		ssize = user_segment_size(addr);
 		vsid = get_vsid(mm->context.id, addr, ssize);
 		WARN_ON(vsid == 0);
 	} else {
 		vsid = get_kernel_vsid(addr, mmu_kernel_ssize);
 		ssize = mmu_kernel_ssize;
 	}
 	vaddr = hpt_va(addr, vsid, ssize);
 	rpte = __real_pte(__pte(pte), ptep);

 	/*
 	 * Check if we have an active batch on this CPU. If not, just
 	 * flush now and return. For now, we don global invalidates
 	 * in that case, might be worth testing the mm cpu mask though
 	 * and decide to use local invalidates instead...
 	 */
 	if (!batch->active) {
 		flush_hash_page(vaddr, rpte, psize, ssize, 0);
 		return;
 	}

 	/*
 	 * This can happen when we are in the middle of a TLB batch and
 	 * we encounter memory pressure (eg copy_page_range when it tries
 	 * to allocate a new pte). If we have to reclaim memory and end
 	 * up scanning and resetting referenced bits then our batch context
 	 * will change mid stream.
 	 *
 	 * We also need to ensure only one page size is present in a given
 	 * batch
 	 */
 	if (i != 0 && (mm != batch->mm || batch->psize != psize ||
 		       batch->ssize != ssize)) {
 		__flush_tlb_pending(batch);
 		i = 0;
 	}
 	if (i == 0) {
 		batch->mm = mm;
 		batch->psize = psize;
 		batch->ssize = ssize;
 	}
 	batch->pte[i] = rpte;
 	batch->vaddr[i] = vaddr;
 	batch->index = ++i;
 	if (i >= PPC64_TLB_BATCH_NR)
 		__flush_tlb_pending(batch);
 }

 /*
  * This function is called when terminating an mmu batch or when a batch
  * is full. It will perform the flush of all the entries currently stored
  * in a batch.
  *
  * Must be called from within some kind of spinlock/non-preempt region...
  */
 void __flush_tlb_pending(struct ppc64_tlb_batch *batch)
 {
 	cpumask_t tmp;
 	int i, local = 0;

 	i = batch->index;
 	tmp = cpumask_of_cpu(smp_processor_id());
 	if (cpus_equal(batch->mm->cpu_vm_mask, tmp))
 		local = 1;
 	if (i == 1)
 		flush_hash_page(batch->vaddr[0], batch->pte[0],
 				batch->psize, batch->ssize, local);
 	else
 		flush_hash_range(i, local);
 	batch->index = 0;
 }

 void pte_free_finish(void)
 {
 	/* This is safe since tlb_gather_mmu has disabled preemption */
 	struct pte_freelist_batch **batchp = &__get_cpu_var(pte_freelist_cur);

 	if (*batchp == NULL)
 		return;
 	pte_free_submit(*batchp);
 	*batchp = NULL;
 }

 /**
  * __flush_hash_table_range - Flush all HPTEs for a given address range
  *                            from the hash table (and the TLB). But keeps
  *                            the linux PTEs intact.
  *
  * @mm		: mm_struct of the target address space (generally init_mm)
  * @start	: starting address
  * @end         : ending address (not included in the flush)
  *
  * This function is mostly to be used by some IO hotplug code in order
  * to remove all hash entries from a given address range used to map IO
  * space on a removed PCI-PCI bidge without tearing down the full mapping
  * since 64K pages may overlap with other bridges when using 64K pages
  * with 4K HW pages on IO space.
  *
  * Because of that usage pattern, it's only available with CONFIG_HOTPLUG
  * and is implemented for small size rather than speed.
  */
 #ifdef CONFIG_HOTPLUG

 void __flush_hash_table_range(struct mm_struct *mm, unsigned long start,
 			      unsigned long end)
 {
 	unsigned long flags;

 	start = _ALIGN_DOWN(start, PAGE_SIZE);
 	end = _ALIGN_UP(end, PAGE_SIZE);

 	BUG_ON(!mm->pgd);

 	/* Note: Normally, we should only ever use a batch within a
 	 * PTE locked section. This violates the rule, but will work
 	 * since we don't actually modify the PTEs, we just flush the
 	 * hash while leaving the PTEs intact (including their reference
 	 * to being hashed). This is not the most performance oriented
 	 * way to do things but is fine for our needs here.
 	 */
 	local_irq_save(flags);
 	arch_enter_lazy_mmu_mode();
 	for (; start < end; start += PAGE_SIZE) {
 		pte_t *ptep = find_linux_pte(mm->pgd, start);
 		unsigned long pte;

 		if (ptep == NULL)
 			continue;
 		pte = pte_val(*ptep);
 		if (!(pte & _PAGE_HASHPTE))
 			continue;
 		hpte_need_flush(mm, start, ptep, pte, 0);
 	}
 	arch_leave_lazy_mmu_mode();
 	local_irq_restore(flags);
 }

 #endif /* CONFIG_HOTPLUG */
	/*
	* This file contains the routines for flushing entries from the
	* TLB and MMU hash table.
	*
	* Derived from arch/ppc64/mm/init.c:
	* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
	*
	* Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
	* and Cort Dougan (PReP) (cort@cs.nmt.edu)
	* Copyright (C) 1996 Paul Mackerras
	*
	* Derived from "arch/i386/mm/init.c"
	* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
	*
	* Dave Engebretsen <engebret@us.ibm.com>
	* Rework for PPC64 port.
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License
	* as published by the Free Software Foundation; either version
	* 2 of the License, or (at your option) any later version.
	*/

	#include <linux/kernel.h>
	#include <linux/mm.h>
	#include <linux/init.h>
	#include <linux/percpu.h>
	#include <linux/hardirq.h>
	#include <asm/pgalloc.h>
	#include <asm/tlbflush.h>
	#include <asm/tlb.h>
	#include <asm/bug.h>

	DEFINE_PER_CPU(struct ppc64_tlb_batch, ppc64_tlb_batch);

	/* This is declared as we are using the more or less generic
	* arch/powerpc/include/asm/tlb.h file -- tgall
	*/
	DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
	static DEFINE_PER_CPU(struct pte_freelist_batch *, pte_freelist_cur);
	static unsigned long pte_freelist_forced_free;

	struct pte_freelist_batch
	{
	struct rcu_head rcu;
	unsigned int index;
	pgtable_free_t tables[0];
	};

	#define PTE_FREELIST_SIZE \
	((PAGE_SIZE - sizeof(struct pte_freelist_batch)) \
	/ sizeof(pgtable_free_t))

	static void pte_free_smp_sync(void *arg)
	{
	/* Do nothing, just ensure we sync with all CPUs */
	}

	/* This is only called when we are critically out of memory
	* (and fail to get a page in pte_free_tlb).
	*/
	static void pgtable_free_now(pgtable_free_t pgf)
	{
	pte_freelist_forced_free++;

	smp_call_function(pte_free_smp_sync, NULL, 1);

	pgtable_free(pgf);
	}

	static void pte_free_rcu_callback(struct rcu_head *head)
	{
	struct pte_freelist_batch *batch =
	container_of(head, struct pte_freelist_batch, rcu);
	unsigned int i;

	for (i = 0; i < batch->index; i++)
	pgtable_free(batch->tables[i]);

	free_page((unsigned long)batch);
	}

	static void pte_free_submit(struct pte_freelist_batch *batch)
	{
	INIT_RCU_HEAD(&batch->rcu);
	call_rcu(&batch->rcu, pte_free_rcu_callback);
	}

	void pgtable_free_tlb(struct mmu_gather *tlb, pgtable_free_t pgf)
	{
	/* This is safe since tlb_gather_mmu has disabled preemption */
	cpumask_t local_cpumask = cpumask_of_cpu(smp_processor_id());
	struct pte_freelist_batch **batchp = &__get_cpu_var(pte_freelist_cur);

	if (atomic_read(&tlb->mm->mm_users) < 2 \|\|
	cpus_equal(tlb->mm->cpu_vm_mask, local_cpumask)) {
	pgtable_free(pgf);
	return;
	}

	if (*batchp == NULL) {
	batchp = (struct pte_freelist_batch )__get_free_page(GFP_ATOMIC);
	if (*batchp == NULL) {
	pgtable_free_now(pgf);
	return;
	}
	(*batchp)->index = 0;
	}
	(batchp)->tables[(batchp)->index++] = pgf;
	if ((*batchp)->index == PTE_FREELIST_SIZE) {
	pte_free_submit(*batchp);
	*batchp = NULL;
	}
	}

	/*
	* A linux PTE was changed and the corresponding hash table entry
	* neesd to be flushed. This function will either perform the flush
	* immediately or will batch it up if the current CPU has an active
	* batch on it.
	*
	* Must be called from within some kind of spinlock/non-preempt region...
	*/
	void hpte_need_flush(struct mm_struct *mm, unsigned long addr,
	pte_t *ptep, unsigned long pte, int huge)
	{
	struct ppc64_tlb_batch *batch = &__get_cpu_var(ppc64_tlb_batch);
	unsigned long vsid, vaddr;
	unsigned int psize;
	int ssize;
	real_pte_t rpte;
	int i;

	i = batch->index;

	/* We mask the address for the base page size. Huge pages will
	* have applied their own masking already
	*/
	addr &= PAGE_MASK;

	/* Get page size (maybe move back to caller).
	*
	* NOTE: when using special 64K mappings in 4K environment like
	* for SPEs, we obtain the page size from the slice, which thus
	* must still exist (and thus the VMA not reused) at the time
	* of this call
	*/
	if (huge) {
	#ifdef CONFIG_HUGETLB_PAGE
	psize = get_slice_psize(mm, addr);;
	#else
	BUG();
	psize = pte_pagesize_index(mm, addr, pte); /* shutup gcc */
	#endif
	} else
	psize = pte_pagesize_index(mm, addr, pte);

	/* Build full vaddr */
	if (!is_kernel_addr(addr)) {
	ssize = user_segment_size(addr);
	vsid = get_vsid(mm->context.id, addr, ssize);
	WARN_ON(vsid == 0);
	} else {
	vsid = get_kernel_vsid(addr, mmu_kernel_ssize);
	ssize = mmu_kernel_ssize;
	}
	vaddr = hpt_va(addr, vsid, ssize);
	rpte = __real_pte(__pte(pte), ptep);

	/*
	* Check if we have an active batch on this CPU. If not, just
	* flush now and return. For now, we don global invalidates
	* in that case, might be worth testing the mm cpu mask though
	* and decide to use local invalidates instead...
	*/
	if (!batch->active) {
	flush_hash_page(vaddr, rpte, psize, ssize, 0);
	return;
	}

	/*
	* This can happen when we are in the middle of a TLB batch and
	* we encounter memory pressure (eg copy_page_range when it tries
	* to allocate a new pte). If we have to reclaim memory and end
	* up scanning and resetting referenced bits then our batch context
	* will change mid stream.
	*
	* We also need to ensure only one page size is present in a given
	* batch
	*/
	if (i != 0 && (mm != batch->mm \|\| batch->psize != psize \|\|
	batch->ssize != ssize)) {
	__flush_tlb_pending(batch);
	i = 0;
	}
	if (i == 0) {
	batch->mm = mm;
	batch->psize = psize;
	batch->ssize = ssize;
	}
	batch->pte[i] = rpte;
	batch->vaddr[i] = vaddr;
	batch->index = ++i;
	if (i >= PPC64_TLB_BATCH_NR)
	__flush_tlb_pending(batch);
	}

	/*
	* This function is called when terminating an mmu batch or when a batch
	* is full. It will perform the flush of all the entries currently stored
	* in a batch.
	*
	* Must be called from within some kind of spinlock/non-preempt region...
	*/
	void __flush_tlb_pending(struct ppc64_tlb_batch *batch)
	{
	cpumask_t tmp;
	int i, local = 0;

	i = batch->index;
	tmp = cpumask_of_cpu(smp_processor_id());
	if (cpus_equal(batch->mm->cpu_vm_mask, tmp))
	local = 1;
	if (i == 1)
	flush_hash_page(batch->vaddr[0], batch->pte[0],
	batch->psize, batch->ssize, local);
	else
	flush_hash_range(i, local);
	batch->index = 0;
	}

	void pte_free_finish(void)
	{
	/* This is safe since tlb_gather_mmu has disabled preemption */
	struct pte_freelist_batch **batchp = &__get_cpu_var(pte_freelist_cur);

	if (*batchp == NULL)
	return;
	pte_free_submit(*batchp);
	*batchp = NULL;
	}

	/**
	* __flush_hash_table_range - Flush all HPTEs for a given address range
	* from the hash table (and the TLB). But keeps
	* the linux PTEs intact.
	*
	* @mm : mm_struct of the target address space (generally init_mm)
	* @start : starting address
	* @end : ending address (not included in the flush)
	*
	* This function is mostly to be used by some IO hotplug code in order
	* to remove all hash entries from a given address range used to map IO
	* space on a removed PCI-PCI bidge without tearing down the full mapping
	* since 64K pages may overlap with other bridges when using 64K pages
	* with 4K HW pages on IO space.
	*
	* Because of that usage pattern, it's only available with CONFIG_HOTPLUG
	* and is implemented for small size rather than speed.
	*/
	#ifdef CONFIG_HOTPLUG

	void __flush_hash_table_range(struct mm_struct *mm, unsigned long start,
	unsigned long end)
	{
	unsigned long flags;

	start = _ALIGN_DOWN(start, PAGE_SIZE);
	end = _ALIGN_UP(end, PAGE_SIZE);

	BUG_ON(!mm->pgd);

	/* Note: Normally, we should only ever use a batch within a
	* PTE locked section. This violates the rule, but will work
	* since we don't actually modify the PTEs, we just flush the
	* hash while leaving the PTEs intact (including their reference
	* to being hashed). This is not the most performance oriented
	* way to do things but is fine for our needs here.
	*/
	local_irq_save(flags);
	arch_enter_lazy_mmu_mode();
	for (; start < end; start += PAGE_SIZE) {
	pte_t *ptep = find_linux_pte(mm->pgd, start);
	unsigned long pte;

	if (ptep == NULL)
	continue;
	pte = pte_val(*ptep);
	if (!(pte & _PAGE_HASHPTE))
	continue;
	hpte_need_flush(mm, start, ptep, pte, 0);
	}
	arch_leave_lazy_mmu_mode();
	local_irq_restore(flags);
	}

	#endif /* CONFIG_HOTPLUG */