mirror of
https://github.com/torvalds/linux.git
synced 2024-11-16 09:02:00 +00:00
acca4f4d9b
There was a race in the kmap_coherent() implementation. While we
guarded against preemption, there was nothing preventing eviction of
the pre-faulted fixmap entry from the UTLB. Under certain workloads
this would result in the fixmap entries used for cache colouring being
evicted from the UTLB in the midst of a copy_page().
In addition to pre-faulting, we also make sure to preserve the PTEs
in the kernel page table and introduce a cached PTE for kmap_coherent()
usage. This follows a similar change on MIPS ("[MIPS] Fix aliasing bug
in copy_to_user_page / copy_from_user_page").
Reported-by: Hideo Saito <saito@densan.co.jp>
Reported-by: CHIKAMA Masaki <masaki.chikama@gmail.com>
Tested-by: Yoshihiro Shimoda <shimoda.yoshihiro@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
147 lines
3.5 KiB
C
147 lines
3.5 KiB
C
/*
|
|
* arch/sh/mm/pg-sh4.c
|
|
*
|
|
* Copyright (C) 1999, 2000, 2002 Niibe Yutaka
|
|
* Copyright (C) 2002 - 2007 Paul Mundt
|
|
*
|
|
* Released under the terms of the GNU GPL v2.0.
|
|
*/
|
|
#include <linux/mm.h>
|
|
#include <linux/init.h>
|
|
#include <linux/mutex.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/highmem.h>
|
|
#include <linux/module.h>
|
|
#include <asm/mmu_context.h>
|
|
#include <asm/cacheflush.h>
|
|
|
|
#define CACHE_ALIAS (current_cpu_data.dcache.alias_mask)
|
|
|
|
#define kmap_get_fixmap_pte(vaddr) \
|
|
pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)), (vaddr)), (vaddr))
|
|
|
|
static pte_t *kmap_coherent_pte;
|
|
|
|
void __init kmap_coherent_init(void)
|
|
{
|
|
unsigned long vaddr;
|
|
|
|
/* cache the first coherent kmap pte */
|
|
vaddr = __fix_to_virt(FIX_CMAP_BEGIN);
|
|
kmap_coherent_pte = kmap_get_fixmap_pte(vaddr);
|
|
}
|
|
|
|
static inline void *kmap_coherent(struct page *page, unsigned long addr)
|
|
{
|
|
enum fixed_addresses idx;
|
|
unsigned long vaddr, flags;
|
|
pte_t pte;
|
|
|
|
inc_preempt_count();
|
|
|
|
idx = (addr & current_cpu_data.dcache.alias_mask) >> PAGE_SHIFT;
|
|
vaddr = __fix_to_virt(FIX_CMAP_END - idx);
|
|
pte = mk_pte(page, PAGE_KERNEL);
|
|
|
|
local_irq_save(flags);
|
|
flush_tlb_one(get_asid(), vaddr);
|
|
local_irq_restore(flags);
|
|
|
|
update_mmu_cache(NULL, vaddr, pte);
|
|
|
|
set_pte(kmap_coherent_pte - (FIX_CMAP_END - idx), pte);
|
|
|
|
return (void *)vaddr;
|
|
}
|
|
|
|
static inline void kunmap_coherent(struct page *page)
|
|
{
|
|
dec_preempt_count();
|
|
preempt_check_resched();
|
|
}
|
|
|
|
/*
|
|
* clear_user_page
|
|
* @to: P1 address
|
|
* @address: U0 address to be mapped
|
|
* @page: page (virt_to_page(to))
|
|
*/
|
|
void clear_user_page(void *to, unsigned long address, struct page *page)
|
|
{
|
|
__set_bit(PG_mapped, &page->flags);
|
|
|
|
clear_page(to);
|
|
if ((((address & PAGE_MASK) ^ (unsigned long)to) & CACHE_ALIAS))
|
|
__flush_wback_region(to, PAGE_SIZE);
|
|
}
|
|
|
|
void copy_to_user_page(struct vm_area_struct *vma, struct page *page,
|
|
unsigned long vaddr, void *dst, const void *src,
|
|
unsigned long len)
|
|
{
|
|
void *vto;
|
|
|
|
__set_bit(PG_mapped, &page->flags);
|
|
|
|
vto = kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK);
|
|
memcpy(vto, src, len);
|
|
kunmap_coherent(vto);
|
|
|
|
if (vma->vm_flags & VM_EXEC)
|
|
flush_cache_page(vma, vaddr, page_to_pfn(page));
|
|
}
|
|
|
|
void copy_from_user_page(struct vm_area_struct *vma, struct page *page,
|
|
unsigned long vaddr, void *dst, const void *src,
|
|
unsigned long len)
|
|
{
|
|
void *vfrom;
|
|
|
|
__set_bit(PG_mapped, &page->flags);
|
|
|
|
vfrom = kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK);
|
|
memcpy(dst, vfrom, len);
|
|
kunmap_coherent(vfrom);
|
|
}
|
|
|
|
void copy_user_highpage(struct page *to, struct page *from,
|
|
unsigned long vaddr, struct vm_area_struct *vma)
|
|
{
|
|
void *vfrom, *vto;
|
|
|
|
__set_bit(PG_mapped, &to->flags);
|
|
|
|
vto = kmap_atomic(to, KM_USER1);
|
|
vfrom = kmap_coherent(from, vaddr);
|
|
copy_page(vto, vfrom);
|
|
kunmap_coherent(vfrom);
|
|
|
|
if (((vaddr ^ (unsigned long)vto) & CACHE_ALIAS))
|
|
__flush_wback_region(vto, PAGE_SIZE);
|
|
|
|
kunmap_atomic(vto, KM_USER1);
|
|
/* Make sure this page is cleared on other CPU's too before using it */
|
|
smp_wmb();
|
|
}
|
|
EXPORT_SYMBOL(copy_user_highpage);
|
|
|
|
/*
|
|
* For SH-4, we have our own implementation for ptep_get_and_clear
|
|
*/
|
|
pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
|
|
{
|
|
pte_t pte = *ptep;
|
|
|
|
pte_clear(mm, addr, ptep);
|
|
if (!pte_not_present(pte)) {
|
|
unsigned long pfn = pte_pfn(pte);
|
|
if (pfn_valid(pfn)) {
|
|
struct page *page = pfn_to_page(pfn);
|
|
struct address_space *mapping = page_mapping(page);
|
|
if (!mapping || !mapping_writably_mapped(mapping))
|
|
__clear_bit(PG_mapped, &page->flags);
|
|
}
|
|
}
|
|
return pte;
|
|
}
|