/*
* linux/arch/arm/mm/flush.c
*
* Copyright (C) 1995-2002 Russell King
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <asm/cacheflush.h>
#include <asm/cachetype.h>
#include <asm/system.h>
#include <asm/tlbflush.h>
#include "mm.h"
#ifdef CONFIG_CPU_CACHE_VIPT
#define ALIAS_FLUSH_START 0xffff4000
static void flush_pfn_alias(unsigned long pfn, unsigned long vaddr)
{
unsigned long to = ALIAS_FLUSH_START + (CACHE_COLOUR(vaddr) << PAGE_SHIFT);
const int zero = 0;
set_pte_ext(TOP_PTE(to), pfn_pte(pfn, PAGE_KERNEL), 0);
flush_tlb_kernel_page(to);
asm( "mcrr p15, 0, %1, %0, c14\n"
" mcr p15, 0, %2, c7, c10, 4"
:
: "r" (to), "r" (to + PAGE_SIZE - L1_CACHE_BYTES), "r" (zero)
: "cc");
__flush_icache_all();
}
void flush_cache_mm(struct mm_struct *mm)
{
if (cache_is_vivt()) {
vivt_flush_cache_mm(mm);
return;
}
if (cache_is_vipt_aliasing()) {
asm( "mcr p15, 0, %0, c7, c14, 0\n"
" mcr p15, 0, %0, c7, c10, 4"
:
: "r" (0)
: "cc");
__flush_icache_all();
}
}
void flush_cache_range(struct vm_area_struct *vma, unsigned long start, unsigned long end)
{
if (cache_is_vivt()) {
vivt_flush_cache_range(vma, start, end);
return;
}
if (cache_is_vipt_aliasing()) {
asm( "mcr p15, 0, %0, c7, c14, 0\n"
" mcr p15, 0, %0, c7, c10, 4"
:
: "r" (0)
: "cc");
__flush_icache_all();
}
}
void flush_cache_page(struct vm_area_struct *vma, unsigned long user_addr, unsigned long pfn)
{
if (cache_is_vivt()) {
vivt_flush_cache_page(vma, user_addr, pfn);
return;
}
if (cache_is_vipt_aliasing())
flush_pfn_alias(pfn, user_addr);
}
void flush_ptrace_access(struct vm_area_struct *vma, struct page *page,
unsigned long uaddr, void *kaddr,
unsigned long len, int write)
{
if (cache_is_vivt()) {
vivt_flush_ptrace_access(vma, page, uaddr, kaddr, len, write);
return;
}
if (cache_is_vipt_aliasing()) {
flush_pfn_alias(page_to_pfn(page), uaddr);
return;
}
/* VIPT non-aliasing cache */
if (cpumask_test_cpu(smp_processor_id(), mm_cpumask(vma->vm_mm)) &&
vma->vm_flags & VM_EXEC) {
unsigned long addr = (unsigned long)kaddr;
/* only flushing the kernel mapping on non-aliasing VIPT */
__cpuc_coherent_kern_range(addr, addr + len);
}
}
#else
#define flush_pfn_alias(pfn,vaddr) do { } while (0)
#endif
void __flush_dcache_page(struct address_space *mapping, struct page *page)
{
/*
* Writeback any data associated with the kernel mapping of this
* page. This ensures that data in the physical page is mutually
* coherent with the kernels mapping.
*/
#ifdef CONFIG_HIGHMEM
/*
* kmap_atomic() doesn't set the page virtual address, and
* kunmap_atomic() takes care of cache flushing already.
*/
if (page_address(page))
#endif
__cpuc_flush_dcache_page(page_address(page));
/*
* If this is a page cache page, and we have an aliasing VIPT cache,
* we only need to do one flush - which would be at the relevant
* userspace colour, which is congruent with page->index.
*/
if (mapping && cache_is_vipt_aliasing())
flush_pfn_alias(page_to_pfn(page),
page->index << PAGE_CACHE_SHIFT);
}
static void __flush_dcache_aliases(struct address_space *mapping, struct page *page)
{
struct mm_struct *mm = current->active_mm;
struct vm_area_struct *mpnt;
struct prio_tree_iter iter;
pgoff_t pgoff;
/*
* There are possible user space mappings of this page:
* - VIVT cache: we need to also write back and invalidate all user
* data in the current VM view associated with this page.
* - aliasing VIPT: we only need to find one mapping of this page.
*/
pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
flush_dcache_mmap_lock(mapping);
vma_prio_tree_foreach(mpnt, &iter, &mapping->i_mmap, pgoff, pgoff) {
unsigned long offset;
/*
* If this VMA is not in our MM, we can ignore it.
*/
if (mpnt->vm_mm != mm)
continue;
if (!(mpnt->vm_flags & VM_MAYSHARE))
continue;
offset = (pgoff - mpnt->vm_pgoff) << PAGE_SHIFT;
flush_cache_page(mpnt, mpnt->vm_start + offset, page_to_pfn(page));
}
flush_dcache_mmap_unlock(mapping);
}
/*
* Ensure cache coherency between kernel mapping and userspace mapping
* of this page.
*
* We have three cases to consider:
* - VIPT non-aliasing cache: fully coherent so nothing required.
* - VIVT: fully aliasing, so we need to handle every alias in our
* current VM view.
* - VIPT aliasing: need to handle one alias in our current VM view.
*
* If we need to handle aliasing:
* If the page only exists in the page cache and there are no user
* space mappings, we can be lazy and remember that we may have dirty
* kernel cache lines for later. Otherwise, we assume we have
* aliasing mappings.
*
* Note that we disable the lazy flush for SMP.
*/
void flush_dcache_page(struct page *page)
{
struct address_space *mapping = page_mapping(page);
#ifndef CONFIG_SMP
if (!PageHighMem(page) && mapping && !mapping_mapped(mapping))
set_bit(PG_dcache_dirty, &page->flags);
else
#endif
{
__flush_dcache_page(mapping, page);
if (mapping && cache_is_vivt())
__flush_dcache_aliases(mapping, page);
else if (mapping)
__flush_icache_all();
}
}
EXPORT_SYMBOL(flush_dcache_page);
/*
* Flush an anonymous page so that users of get_user_pages()
* can safely access the data. The expected sequence is:
*
* get_user_pages()
* -> flush_anon_page
* memcpy() to/from page
* if written to page, flush_dcache_page()
*/
void __flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr)
{
unsigned long pfn;
/* VIPT non-aliasing caches need do nothing */
if (cache_is_vipt_nonaliasing())
return;
/*
* Write back and invalidate userspace mapping.
*/
pfn = page_to_pfn(page);
if (cache_is_vivt()) {
flush_cache_page(vma, vmaddr, pfn);
} else {
/*
* For aliasing VIPT, we can flush an alias of the
* userspace address only.
*/
flush_pfn_alias(pfn, vmaddr);
}
/*
* Invalidate kernel mapping. No data should be contained
* in this mapping of the page. FIXME: this is overkill
* since we actually ask for a write-back and invalidate.
*/
__cpuc_flush_dcache_page(page_address(page));
}
