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sh: Fix fatal oops in copy_user_page() on sh4a (SH7780).

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We had a pretty interesting oops happening, where copy_user_page()
was down()'ing p3map_sem[] with a bogus offset (particularly, an
offset that hadn't been initialized with sema_init(), due to the
mismatch between cpu_data->dcache.n_aliases and what was assumed
based off of the old CACHE_ALIAS value).

Luckily, spinlock debugging caught this for us, and so we drop
the old hardcoded CACHE_ALIAS for sh4 completely and rely on the
run-time probed cpu_data->dcache.alias_mask. This in turn gets
the p3map_sem[] index right, and everything works again.

While we're at it, also convert to 4-level page tables..

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This commit is contained in:
Paul Mundt 2006-09-27 14:38:02 +09:00
parent 75c92acdd5
commit 8b395265f8
2 changed files with 14 additions and 14 deletions
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24
arch/sh/mm/pg-sh4.c
View File

@ -2,7 +2,7 @@
* arch/sh/mm/pg-sh4.c
*
* Copyright (C) 1999, 2000, 2002 Niibe Yutaka
* Copyright (C) 2002 Paul Mundt
* Copyright (C) 2002 - 2005 Paul Mundt
*
* Released under the terms of the GNU GPL v2.0.
*/
@ -23,6 +23,8 @@
extern struct semaphore p3map_sem[];
#define CACHE_ALIAS (cpu_data->dcache.alias_mask)
/*
* clear_user_page
* @to: P1 address
@ -35,14 +37,15 @@ void clear_user_page(void *to, unsigned long address, struct page *page)
if (((address ^ (unsigned long)to) & CACHE_ALIAS) == 0)
clear_page(to);
else {
pgprot_t pgprot = __pgprot(_PAGE_PRESENT |
pgprot_t pgprot = __pgprot(_PAGE_PRESENT |
_PAGE_RW | _PAGE_CACHABLE |
_PAGE_DIRTY | _PAGE_ACCESSED |
_PAGE_DIRTY | _PAGE_ACCESSED |
_PAGE_HW_SHARED | _PAGE_FLAGS_HARD);
unsigned long phys_addr = PHYSADDR(to);
unsigned long p3_addr = P3SEG + (address & CACHE_ALIAS);
pgd_t *dir = pgd_offset_k(p3_addr);
pmd_t *pmd = pmd_offset(dir, p3_addr);
pgd_t *pgd = pgd_offset_k(p3_addr);
pud_t *pud = pud_offset(pgd, p3_addr);
pmd_t *pmd = pmd_offset(pud, p3_addr);
pte_t *pte = pte_offset_kernel(pmd, p3_addr);
pte_t entry;
unsigned long flags;
@ -67,21 +70,22 @@ void clear_user_page(void *to, unsigned long address, struct page *page)
* @address: U0 address to be mapped
* @page: page (virt_to_page(to))
*/
void copy_user_page(void *to, void *from, unsigned long address,
void copy_user_page(void *to, void *from, unsigned long address,
struct page *page)
{
__set_bit(PG_mapped, &page->flags);
if (((address ^ (unsigned long)to) & CACHE_ALIAS) == 0)
copy_page(to, from);
else {
pgprot_t pgprot = __pgprot(_PAGE_PRESENT |
pgprot_t pgprot = __pgprot(_PAGE_PRESENT |
_PAGE_RW | _PAGE_CACHABLE |
_PAGE_DIRTY | _PAGE_ACCESSED |
_PAGE_DIRTY | _PAGE_ACCESSED |
_PAGE_HW_SHARED | _PAGE_FLAGS_HARD);
unsigned long phys_addr = PHYSADDR(to);
unsigned long p3_addr = P3SEG + (address & CACHE_ALIAS);
pgd_t *dir = pgd_offset_k(p3_addr);
pmd_t *pmd = pmd_offset(dir, p3_addr);
pgd_t *pgd = pgd_offset_k(p3_addr);
pud_t *pud = pud_offset(pgd, p3_addr);
pmd_t *pmd = pmd_offset(pud, p3_addr);
pte_t *pte = pte_offset_kernel(pmd, p3_addr);
pte_t entry;
unsigned long flags;

4
include/asm-sh/cpu-sh4/cacheflush.h
View File

@ -16,10 +16,6 @@
* caching; in which case they're only semi-broken),
* so we need them.
*/
/* Page is 4K, OC size is 16K, there are four lines. */
#define CACHE_ALIAS 0x00003000
struct page;
struct mm_struct;
struct vm_area_struct;