/*
* 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);
/*
* 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.
*/
void hpte_need_flush(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, unsigned long pte, int huge)
{
unsigned long vpn;
struct ppc64_tlb_batch *batch = &get_cpu_var(ppc64_tlb_batch);
unsigned long vsid;
unsigned int psize;
int ssize;
real_pte_t rpte;
int i;
i = batch->index;
/* 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);
/* Mask the address for the correct page size */
addr &= ~((1UL << mmu_psize_defs[psize].shift) - 1);
#else
BUG();
psize = pte_pagesize_index(mm, addr, pte); /* shutup gcc */
#endif
} else {
psize = pte_pagesize_index(mm, addr, pte);
/* Mask the address for the standard page size. If we
* have a 64k page kernel, but the hardware does not
* support 64k pages, this might be different from the
* hardware page size encoded in the slice table. */
addr &= PAGE_MASK;
}
/* 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;
}
vpn = hpt_vpn(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(vpn, rpte, psize, ssize, 0);
put_cpu_var(ppc64_tlb_batch);
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->vpn[i] = vpn;
batch->index = ++i;
if (i >= PPC64_TLB_BATCH_NR)
__flush_tlb_pending(batch);
put_cpu_var(ppc64_tlb_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)
{
const struct cpumask *tmp;
int i, local = 0;
i = batch->index;
tmp = cpumask_of(smp_processor_id());
if (cpumask_equal(mm_cpumask(batch->mm), tmp))
local = 1;
if (i == 1)
flush_hash_page(batch->vpn[0], batch->pte[0],
batch->psize, batch->ssize, local);
else
flush_hash_range(i, local);
batch->index = 0;
}
void tlb_flush(struct mmu_gather *tlb)
{
struct ppc64_tlb_batch *tlbbatch = &get_cpu_var(ppc64_tlb_batch);
/* If there's a TLB batch pending, then we must flush it because the
* pages are going to be freed and we really don't want to have a CPU
* access a freed page because it has a stale TLB
*/
if (tlbbatch->index)
__flush_tlb_pending(tlbbatch);
put_cpu_var(ppc64_tlb_batch);
}
/**
* __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 */
