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Diffstat (limited to 'arch/arm/mm/copypage-xscale.c')
| -rw-r--r-- | arch/arm/mm/copypage-xscale.c | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/arch/arm/mm/copypage-xscale.c b/arch/arm/mm/copypage-xscale.c new file mode 100644 index 00000000..649bbcd3 --- /dev/null +++ b/arch/arm/mm/copypage-xscale.c @@ -0,0 +1,142 @@ +/* + * linux/arch/arm/lib/copypage-xscale.S + * + * Copyright (C) 1995-2005 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 <linux/highmem.h> + +#include <asm/pgtable.h> +#include <asm/tlbflush.h> +#include <asm/cacheflush.h> + +#include "mm.h" + +/* + * 0xffff8000 to 0xffffffff is reserved for any ARM architecture + * specific hacks for copying pages efficiently. + */ +#define COPYPAGE_MINICACHE 0xffff8000 + +#define minicache_pgprot __pgprot(L_PTE_PRESENT | L_PTE_YOUNG | \ + L_PTE_MT_MINICACHE) + +static DEFINE_SPINLOCK(minicache_lock); + +/* + * XScale mini-dcache optimised copy_user_highpage + * + * We flush the destination cache lines just before we write the data into the + * corresponding address. Since the Dcache is read-allocate, this removes the + * Dcache aliasing issue. The writes will be forwarded to the write buffer, + * and merged as appropriate. + */ +static void __naked +mc_copy_user_page(void *from, void *to) +{ + /* + * Strangely enough, best performance is achieved + * when prefetching destination as well. (NP) + */ + asm volatile( + "stmfd sp!, {r4, r5, lr} \n\ + mov lr, %2 \n\ + pld [r0, #0] \n\ + pld [r0, #32] \n\ + pld [r1, #0] \n\ + pld [r1, #32] \n\ +1: pld [r0, #64] \n\ + pld [r0, #96] \n\ + pld [r1, #64] \n\ + pld [r1, #96] \n\ +2: ldrd r2, [r0], #8 \n\ + ldrd r4, [r0], #8 \n\ + mov ip, r1 \n\ + strd r2, [r1], #8 \n\ + ldrd r2, [r0], #8 \n\ + strd r4, [r1], #8 \n\ + ldrd r4, [r0], #8 \n\ + strd r2, [r1], #8 \n\ + strd r4, [r1], #8 \n\ + mcr p15, 0, ip, c7, c10, 1 @ clean D line\n\ + ldrd r2, [r0], #8 \n\ + mcr p15, 0, ip, c7, c6, 1 @ invalidate D line\n\ + ldrd r4, [r0], #8 \n\ + mov ip, r1 \n\ + strd r2, [r1], #8 \n\ + ldrd r2, [r0], #8 \n\ + strd r4, [r1], #8 \n\ + ldrd r4, [r0], #8 \n\ + strd r2, [r1], #8 \n\ + strd r4, [r1], #8 \n\ + mcr p15, 0, ip, c7, c10, 1 @ clean D line\n\ + subs lr, lr, #1 \n\ + mcr p15, 0, ip, c7, c6, 1 @ invalidate D line\n\ + bgt 1b \n\ + beq 2b \n\ + ldmfd sp!, {r4, r5, pc} " + : + : "r" (from), "r" (to), "I" (PAGE_SIZE / 64 - 1)); +} + +void xscale_mc_copy_user_highpage(struct page *to, struct page *from, + unsigned long vaddr, struct vm_area_struct *vma) +{ + void *kto = kmap_atomic(to, KM_USER1); + + if (!test_and_set_bit(PG_dcache_clean, &from->flags)) + __flush_dcache_page(page_mapping(from), from); + + spin_lock(&minicache_lock); + + set_pte_ext(TOP_PTE(COPYPAGE_MINICACHE), pfn_pte(page_to_pfn(from), minicache_pgprot), 0); + flush_tlb_kernel_page(COPYPAGE_MINICACHE); + + mc_copy_user_page((void *)COPYPAGE_MINICACHE, kto); + + spin_unlock(&minicache_lock); + + kunmap_atomic(kto, KM_USER1); +} + +/* + * XScale optimised clear_user_page + */ +void +xscale_mc_clear_user_highpage(struct page *page, unsigned long vaddr) +{ + void *ptr, *kaddr = kmap_atomic(page, KM_USER0); + asm volatile( + "mov r1, %2 \n\ + mov r2, #0 \n\ + mov r3, #0 \n\ +1: mov ip, %0 \n\ + strd r2, [%0], #8 \n\ + strd r2, [%0], #8 \n\ + strd r2, [%0], #8 \n\ + strd r2, [%0], #8 \n\ + mcr p15, 0, ip, c7, c10, 1 @ clean D line\n\ + subs r1, r1, #1 \n\ + mcr p15, 0, ip, c7, c6, 1 @ invalidate D line\n\ + bne 1b" + : "=r" (ptr) + : "0" (kaddr), "I" (PAGE_SIZE / 32) + : "r1", "r2", "r3", "ip"); + kunmap_atomic(kaddr, KM_USER0); +} + +struct cpu_user_fns xscale_mc_user_fns __initdata = { + .cpu_clear_user_highpage = xscale_mc_clear_user_highpage, + .cpu_copy_user_highpage = xscale_mc_copy_user_highpage, +}; |