1/* Flush dcache and invalidate icache when the dcache is in writeback mode
  2 *
  3 * Copyright (C) 2010 Red Hat, Inc. All Rights Reserved.
  4 * Written by David Howells (dhowells@redhat.com)
  5 *
  6 * This program is free software; you can redistribute it and/or
  7 * modify it under the terms of the GNU General Public Licence
  8 * as published by the Free Software Foundation; either version
  9 * 2 of the Licence, or (at your option) any later version.
 10 */
 11#include <linux/module.h>
 12#include <linux/mm.h>
 13#include <asm/cacheflush.h>
 14#include <asm/smp.h>
 15#include "cache-smp.h"
 16
 17/**
 18 * flush_icache_page - Flush a page from the dcache and invalidate the icache
 19 * @vma: The VMA the page is part of.
 20 * @page: The page to be flushed.
 21 *
 22 * Write a page back from the dcache and invalidate the icache so that we can
 23 * run code from it that we've just written into it
 24 */
 25void flush_icache_page(struct vm_area_struct *vma, struct page *page)
 26{
 27	unsigned long start = page_to_phys(page);
 28	unsigned long flags;
 29
 30	flags = smp_lock_cache();
 31
 32	mn10300_local_dcache_flush_page(start);
 33	mn10300_local_icache_inv_page(start);
 34
 35	smp_cache_call(SMP_IDCACHE_INV_FLUSH_RANGE, start, start + PAGE_SIZE);
 36	smp_unlock_cache(flags);
 37}
 38EXPORT_SYMBOL(flush_icache_page);
 39
 40/**
 41 * flush_icache_page_range - Flush dcache and invalidate icache for part of a
 42 *				single page
 43 * @start: The starting virtual address of the page part.
 44 * @end: The ending virtual address of the page part.
 45 *
 46 * Flush the dcache and invalidate the icache for part of a single page, as
 47 * determined by the virtual addresses given.  The page must be in the paged
 48 * area.
 49 */
 50static void flush_icache_page_range(unsigned long start, unsigned long end)
 51{
 52	unsigned long addr, size, off;
 53	struct page *page;
 54	pgd_t *pgd;
 55	pud_t *pud;
 56	pmd_t *pmd;
 57	pte_t *ppte, pte;
 58
 59	/* work out how much of the page to flush */
 60	off = start & ~PAGE_MASK;
 61	size = end - start;
 62
 63	/* get the physical address the page is mapped to from the page
 64	 * tables */
 65	pgd = pgd_offset(current->mm, start);
 66	if (!pgd || !pgd_val(*pgd))
 67		return;
 68
 69	pud = pud_offset(pgd, start);
 70	if (!pud || !pud_val(*pud))
 71		return;
 72
 73	pmd = pmd_offset(pud, start);
 74	if (!pmd || !pmd_val(*pmd))
 75		return;
 76
 77	ppte = pte_offset_map(pmd, start);
 78	if (!ppte)
 79		return;
 80	pte = *ppte;
 81	pte_unmap(ppte);
 82
 83	if (pte_none(pte))
 84		return;
 85
 86	page = pte_page(pte);
 87	if (!page)
 88		return;
 89
 90	addr = page_to_phys(page);
 91
 92	/* flush the dcache and invalidate the icache coverage on that
 93	 * region */
 94	mn10300_local_dcache_flush_range2(addr + off, size);
 95	mn10300_local_icache_inv_range2(addr + off, size);
 96	smp_cache_call(SMP_IDCACHE_INV_FLUSH_RANGE, start, end);
 97}
 98
 99/**
100 * flush_icache_range - Globally flush dcache and invalidate icache for region
101 * @start: The starting virtual address of the region.
102 * @end: The ending virtual address of the region.
103 *
104 * This is used by the kernel to globally flush some code it has just written
105 * from the dcache back to RAM and then to globally invalidate the icache over
106 * that region so that that code can be run on all CPUs in the system.
107 */
108void flush_icache_range(unsigned long start, unsigned long end)
109{
110	unsigned long start_page, end_page;
111	unsigned long flags;
112
113	flags = smp_lock_cache();
114
115	if (end > 0x80000000UL) {
116		/* addresses above 0xa0000000 do not go through the cache */
117		if (end > 0xa0000000UL) {
118			end = 0xa0000000UL;
119			if (start >= end)
120				goto done;
121		}
122
123		/* kernel addresses between 0x80000000 and 0x9fffffff do not
124		 * require page tables, so we just map such addresses
125		 * directly */
126		start_page = (start >= 0x80000000UL) ? start : 0x80000000UL;
127		mn10300_local_dcache_flush_range(start_page, end);
128		mn10300_local_icache_inv_range(start_page, end);
129		smp_cache_call(SMP_IDCACHE_INV_FLUSH_RANGE, start_page, end);
130		if (start_page == start)
131			goto done;
132		end = start_page;
133	}
134
135	start_page = start & PAGE_MASK;
136	end_page = (end - 1) & PAGE_MASK;
137
138	if (start_page == end_page) {
139		/* the first and last bytes are on the same page */
140		flush_icache_page_range(start, end);
141	} else if (start_page + 1 == end_page) {
142		/* split over two virtually contiguous pages */
143		flush_icache_page_range(start, end_page);
144		flush_icache_page_range(end_page, end);
145	} else {
146		/* more than 2 pages; just flush the entire cache */
147		mn10300_dcache_flush();
148		mn10300_icache_inv();
149		smp_cache_call(SMP_IDCACHE_INV_FLUSH, 0, 0);
150	}
151
152done:
153	smp_unlock_cache(flags);
154}
155EXPORT_SYMBOL(flush_icache_range);