/*
* 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 */
