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linux/arch/mips/mm/cache.c
Lars Persson 2a4a8b1e5d MIPS: Remove race window in page fault handling 
Multicore MIPSes without I/D hardware coherency suffered from a race
condition in the page fault handler. The page table entry was
published before any pending lazy D-cache flush was committed, hence
it allowed execution of stale page cache data by other VPEs in the
system.

To make the cache handling safe we need to perform flushing already in
the set_pte_at function. MIPSes without coherent I-caches can get a
small increase in flushes due to the unavailability of the execute
flag in set_pte_at.

[ralf@linux-mips.org: outlining set_pte_at() saves a good k in a test
build, so I moved its definition from pgtable.h to cache.c.]

Signed-off-by: Lars Persson <larper@axis.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7511/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2014-08-19 13:31:09 +02:00

240 lines
7.1 KiB
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/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1994 - 2003, 06, 07 by Ralf Baechle (ralf@linux-mips.org)
* Copyright (C) 2007 MIPS Technologies, Inc.
*/
#include <linux/fs.h>
#include <linux/fcntl.h>
#include <linux/kernel.h>
#include <linux/linkage.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/syscalls.h>
#include <linux/mm.h>
#include <asm/cacheflush.h>
#include <asm/processor.h>
#include <asm/cpu.h>
#include <asm/cpu-features.h>
/* Cache operations. */
void (*flush_cache_all)(void);
void (*__flush_cache_all)(void);
void (*flush_cache_mm)(struct mm_struct *mm);
void (*flush_cache_range)(struct vm_area_struct *vma, unsigned long start,
unsigned long end);
void (*flush_cache_page)(struct vm_area_struct *vma, unsigned long page,
unsigned long pfn);
void (*flush_icache_range)(unsigned long start, unsigned long end);
EXPORT_SYMBOL_GPL(flush_icache_range);
void (*local_flush_icache_range)(unsigned long start, unsigned long end);
EXPORT_SYMBOL_GPL(local_flush_icache_range);
void (*__flush_cache_vmap)(void);
void (*__flush_cache_vunmap)(void);
void (*__flush_kernel_vmap_range)(unsigned long vaddr, int size);
EXPORT_SYMBOL_GPL(__flush_kernel_vmap_range);
void (*__invalidate_kernel_vmap_range)(unsigned long vaddr, int size);
/* MIPS specific cache operations */
void (*flush_cache_sigtramp)(unsigned long addr);
void (*local_flush_data_cache_page)(void * addr);
void (*flush_data_cache_page)(unsigned long addr);
void (*flush_icache_all)(void);
EXPORT_SYMBOL_GPL(local_flush_data_cache_page);
EXPORT_SYMBOL(flush_data_cache_page);
EXPORT_SYMBOL(flush_icache_all);
#if defined(CONFIG_DMA_NONCOHERENT) || defined(CONFIG_DMA_MAYBE_COHERENT)
/* DMA cache operations. */
void (*_dma_cache_wback_inv)(unsigned long start, unsigned long size);
void (*_dma_cache_wback)(unsigned long start, unsigned long size);
void (*_dma_cache_inv)(unsigned long start, unsigned long size);
EXPORT_SYMBOL(_dma_cache_wback_inv);
#endif /* CONFIG_DMA_NONCOHERENT || CONFIG_DMA_MAYBE_COHERENT */
/*
* We could optimize the case where the cache argument is not BCACHE but
* that seems very atypical use ...
*/
SYSCALL_DEFINE3(cacheflush, unsigned long, addr, unsigned long, bytes,
unsigned int, cache)
{
if (bytes == 0)
return 0;
if (!access_ok(VERIFY_WRITE, (void __user *) addr, bytes))
return -EFAULT;
flush_icache_range(addr, addr + bytes);
return 0;
}
void __flush_dcache_page(struct page *page)
{
struct address_space *mapping = page_mapping(page);
unsigned long addr;
if (PageHighMem(page))
return;
if (mapping && !mapping_mapped(mapping)) {
SetPageDcacheDirty(page);
return;
}
/*
* We could delay the flush for the !page_mapping case too. But that
* case is for exec env/arg pages and those are %99 certainly going to
* get faulted into the tlb (and thus flushed) anyways.
*/
addr = (unsigned long) page_address(page);
flush_data_cache_page(addr);
}
EXPORT_SYMBOL(__flush_dcache_page);
void __flush_anon_page(struct page *page, unsigned long vmaddr)
{
unsigned long addr = (unsigned long) page_address(page);
if (pages_do_alias(addr, vmaddr)) {
if (page_mapped(page) && !Page_dcache_dirty(page)) {
void *kaddr;
kaddr = kmap_coherent(page, vmaddr);
flush_data_cache_page((unsigned long)kaddr);
kunmap_coherent();
} else
flush_data_cache_page(addr);
}
}
EXPORT_SYMBOL(__flush_anon_page);
static void mips_flush_dcache_from_pte(pte_t pteval, unsigned long address)
{
struct page *page;
unsigned long pfn = pte_pfn(pteval);
if (unlikely(!pfn_valid(pfn)))
return;
page = pfn_to_page(pfn);
if (page_mapping(page) && Page_dcache_dirty(page)) {
unsigned long page_addr = (unsigned long) page_address(page);
if (!cpu_has_ic_fills_f_dc ||
pages_do_alias(page_addr, address & PAGE_MASK))
flush_data_cache_page(page_addr);
ClearPageDcacheDirty(page);
}
}
void set_pte_at(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, pte_t pteval)
{
if (cpu_has_dc_aliases || !cpu_has_ic_fills_f_dc) {
if (pte_present(pteval))
mips_flush_dcache_from_pte(pteval, addr);
}
set_pte(ptep, pteval);
}
unsigned long _page_cachable_default;
EXPORT_SYMBOL(_page_cachable_default);
static inline void setup_protection_map(void)
{
if (cpu_has_rixi) {
protection_map[0] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ);
protection_map[1] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC);
protection_map[2] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ);
protection_map[3] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC);
protection_map[4] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_READ);
protection_map[5] = __pgprot(_page_cachable_default | _PAGE_PRESENT);
protection_map[6] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_READ);
protection_map[7] = __pgprot(_page_cachable_default | _PAGE_PRESENT);
protection_map[8] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ);
protection_map[9] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC);
protection_map[10] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE | _PAGE_NO_READ);
protection_map[11] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE);
protection_map[12] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_READ);
protection_map[13] = __pgprot(_page_cachable_default | _PAGE_PRESENT);
protection_map[14] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_WRITE | _PAGE_NO_READ);
protection_map[15] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_WRITE);
} else {
protection_map[0] = PAGE_NONE;
protection_map[1] = PAGE_READONLY;
protection_map[2] = PAGE_COPY;
protection_map[3] = PAGE_COPY;
protection_map[4] = PAGE_READONLY;
protection_map[5] = PAGE_READONLY;
protection_map[6] = PAGE_COPY;
protection_map[7] = PAGE_COPY;
protection_map[8] = PAGE_NONE;
protection_map[9] = PAGE_READONLY;
protection_map[10] = PAGE_SHARED;
protection_map[11] = PAGE_SHARED;
protection_map[12] = PAGE_READONLY;
protection_map[13] = PAGE_READONLY;
protection_map[14] = PAGE_SHARED;
protection_map[15] = PAGE_SHARED;
}
}
void cpu_cache_init(void)
{
if (cpu_has_3k_cache) {
extern void __weak r3k_cache_init(void);
r3k_cache_init();
}
if (cpu_has_6k_cache) {
extern void __weak r6k_cache_init(void);
r6k_cache_init();
}
if (cpu_has_4k_cache) {
extern void __weak r4k_cache_init(void);
r4k_cache_init();
}
if (cpu_has_8k_cache) {
extern void __weak r8k_cache_init(void);
r8k_cache_init();
}
if (cpu_has_tx39_cache) {
extern void __weak tx39_cache_init(void);
tx39_cache_init();
}
if (cpu_has_octeon_cache) {
extern void __weak octeon_cache_init(void);
octeon_cache_init();
}
setup_protection_map();
}
int __weak __uncached_access(struct file *file, unsigned long addr)
{
if (file->f_flags & O_DSYNC)
return 1;
return addr >= __pa(high_memory);
}
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