From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 16 Apr 2005 15:20:36 -0700 Subject: Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip! --- arch/arm/mm/minicache.c | 73 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 73 insertions(+) create mode 100644 arch/arm/mm/minicache.c (limited to 'arch/arm/mm/minicache.c') diff --git a/arch/arm/mm/minicache.c b/arch/arm/mm/minicache.c new file mode 100644 index 0000000..dedf2ab --- /dev/null +++ b/arch/arm/mm/minicache.c @@ -0,0 +1,73 @@ +/* + * 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 +#include + +#include +#include +#include + +/* + * 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); -- cgit v1.1