diff options
Diffstat (limited to 'arch/arm/mm/minicache.c')
-rw-r--r-- | arch/arm/mm/minicache.c | 73 |
1 files changed, 0 insertions, 73 deletions
diff --git a/arch/arm/mm/minicache.c b/arch/arm/mm/minicache.c index dedf2ab01b2..e69de29bb2d 100644 --- a/arch/arm/mm/minicache.c +++ b/arch/arm/mm/minicache.c @@ -1,73 +0,0 @@ -/* - * linux/arch/arm/mm/minicache.c - * - * Copyright (C) 2001 Russell King - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License version 2 as - * published by the Free Software Foundation. - * - * This handles the mini data cache, as found on SA11x0 and XScale - * processors. When we copy a user page page, we map it in such a way - * that accesses to this page will not touch the main data cache, but - * will be cached in the mini data cache. This prevents us thrashing - * the main data cache on page faults. - */ -#include <linux/init.h> -#include <linux/mm.h> - -#include <asm/page.h> -#include <asm/pgtable.h> -#include <asm/tlbflush.h> - -/* - * 0xffff8000 to 0xffffffff is reserved for any ARM architecture - * specific hacks for copying pages efficiently. - */ -#define minicache_address (0xffff8000) -#define minicache_pgprot __pgprot(L_PTE_PRESENT | L_PTE_YOUNG | \ - L_PTE_CACHEABLE) - -static pte_t *minicache_pte; - -/* - * Note that this is intended to be called only from the copy_user_page - * asm code; anything else will require special locking to prevent the - * mini-cache space being re-used. (Note: probably preempt unsafe). - * - * We rely on the fact that the minicache is 2K, and we'll be pushing - * 4K of data through it, so we don't actually have to specifically - * flush the minicache when we change the mapping. - * - * Note also: assert(PAGE_OFFSET <= virt < high_memory). - * Unsafe: preempt, kmap. - */ -unsigned long map_page_minicache(unsigned long virt) -{ - set_pte(minicache_pte, pfn_pte(__pa(virt) >> PAGE_SHIFT, minicache_pgprot)); - flush_tlb_kernel_page(minicache_address); - - return minicache_address; -} - -static int __init minicache_init(void) -{ - pgd_t *pgd; - pmd_t *pmd; - - spin_lock(&init_mm.page_table_lock); - - pgd = pgd_offset_k(minicache_address); - pmd = pmd_alloc(&init_mm, pgd, minicache_address); - if (!pmd) - BUG(); - minicache_pte = pte_alloc_kernel(&init_mm, pmd, minicache_address); - if (!minicache_pte) - BUG(); - - spin_unlock(&init_mm.page_table_lock); - - return 0; -} - -core_initcall(minicache_init); |