1/* Invalidate icache when dcache doesn't need invalidation as it's in
  2 * write-through mode
  3 *
  4 * Copyright (C) 2010 Red Hat, Inc. All Rights Reserved.
  5 * Written by David Howells (dhowells@redhat.com)
  6 *
  7 * This program is free software; you can redistribute it and/or
  8 * modify it under the terms of the GNU General Public Licence
  9 * as published by the Free Software Foundation; either version
 10 * 2 of the Licence, or (at your option) any later version.
 11 */
 12#include <linux/module.h>
 13#include <linux/mm.h>
 14#include <asm/cacheflush.h>
 15#include <asm/smp.h>
 16#include "cache-smp.h"
 17
 18/**
 19 * flush_icache_page_range - Flush dcache and invalidate icache for part of a
 20 *				single page
 21 * @start: The starting virtual address of the page part.
 22 * @end: The ending virtual address of the page part.
 23 *
 24 * Invalidate the icache for part of a single page, as determined by the
 25 * virtual addresses given.  The page must be in the paged area.  The dcache is
 26 * not flushed as the cache must be in write-through mode to get here.
 27 */
 28static void flush_icache_page_range(unsigned long start, unsigned long end)
 29{
 30	unsigned long addr, size, off;
 31	struct page *page;
 32	pgd_t *pgd;
 33	pud_t *pud;
 34	pmd_t *pmd;
 35	pte_t *ppte, pte;
 36
 37	/* work out how much of the page to flush */
 38	off = start & ~PAGE_MASK;
 39	size = end - start;
 40
 41	/* get the physical address the page is mapped to from the page
 42	 * tables */
 43	pgd = pgd_offset(current->mm, start);
 44	if (!pgd || !pgd_val(*pgd))
 45		return;
 46
 47	pud = pud_offset(pgd, start);
 48	if (!pud || !pud_val(*pud))
 49		return;
 50
 51	pmd = pmd_offset(pud, start);
 52	if (!pmd || !pmd_val(*pmd))
 53		return;
 54
 55	ppte = pte_offset_map(pmd, start);
 56	if (!ppte)
 57		return;
 58	pte = *ppte;
 59	pte_unmap(ppte);
 60
 61	if (pte_none(pte))
 62		return;
 63
 64	page = pte_page(pte);
 65	if (!page)
 66		return;
 67
 68	addr = page_to_phys(page);
 69
 70	/* invalidate the icache coverage on that region */
 71	mn10300_local_icache_inv_range2(addr + off, size);
 72	smp_cache_call(SMP_ICACHE_INV_RANGE, start, end);
 73}
 74
 75/**
 76 * flush_icache_range - Globally flush dcache and invalidate icache for region
 77 * @start: The starting virtual address of the region.
 78 * @end: The ending virtual address of the region.
 79 *
 80 * This is used by the kernel to globally flush some code it has just written
 81 * from the dcache back to RAM and then to globally invalidate the icache over
 82 * that region so that that code can be run on all CPUs in the system.
 83 */
 84void flush_icache_range(unsigned long start, unsigned long end)
 85{
 86	unsigned long start_page, end_page;
 87	unsigned long flags;
 88
 89	flags = smp_lock_cache();
 90
 91	if (end > 0x80000000UL) {
 92		/* addresses above 0xa0000000 do not go through the cache */
 93		if (end > 0xa0000000UL) {
 94			end = 0xa0000000UL;
 95			if (start >= end)
 96				goto done;
 97		}
 98
 99		/* kernel addresses between 0x80000000 and 0x9fffffff do not
100		 * require page tables, so we just map such addresses
101		 * directly */
102		start_page = (start >= 0x80000000UL) ? start : 0x80000000UL;
103		mn10300_icache_inv_range(start_page, end);
104		smp_cache_call(SMP_ICACHE_INV_RANGE, start, end);
105		if (start_page == start)
106			goto done;
107		end = start_page;
108	}
109
110	start_page = start & PAGE_MASK;
111	end_page = (end - 1) & PAGE_MASK;
112
113	if (start_page == end_page) {
114		/* the first and last bytes are on the same page */
115		flush_icache_page_range(start, end);
116	} else if (start_page + 1 == end_page) {
117		/* split over two virtually contiguous pages */
118		flush_icache_page_range(start, end_page);
119		flush_icache_page_range(end_page, end);
120	} else {
121		/* more than 2 pages; just flush the entire cache */
122		mn10300_local_icache_inv();
123		smp_cache_call(SMP_ICACHE_INV, 0, 0);
124	}
125
126done:
127	smp_unlock_cache(flags);
128}
129EXPORT_SYMBOL(flush_icache_range);