| 1 | /* |
| 2 | * linux/arch/arm/lib/copypage-armv4mc.S |
| 3 | * |
| 4 | * Copyright (C) 1995-2005 Russell King |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License version 2 as |
| 8 | * published by the Free Software Foundation. |
| 9 | * |
| 10 | * This handles the mini data cache, as found on SA11x0 and XScale |
| 11 | * processors. When we copy a user page page, we map it in such a way |
| 12 | * that accesses to this page will not touch the main data cache, but |
| 13 | * will be cached in the mini data cache. This prevents us thrashing |
| 14 | * the main data cache on page faults. |
| 15 | */ |
| 16 | #include <linux/init.h> |
| 17 | #include <linux/mm.h> |
| 18 | #include <linux/highmem.h> |
| 19 | |
| 20 | #include <asm/pgtable.h> |
| 21 | #include <asm/tlbflush.h> |
| 22 | #include <asm/cacheflush.h> |
| 23 | |
| 24 | #include "mm.h" |
| 25 | |
| 26 | #define minicache_pgprot __pgprot(L_PTE_PRESENT | L_PTE_YOUNG | \ |
| 27 | L_PTE_MT_MINICACHE) |
| 28 | |
| 29 | static DEFINE_RAW_SPINLOCK(minicache_lock); |
| 30 | |
| 31 | /* |
| 32 | * ARMv4 mini-dcache optimised copy_user_highpage |
| 33 | * |
| 34 | * We flush the destination cache lines just before we write the data into the |
| 35 | * corresponding address. Since the Dcache is read-allocate, this removes the |
| 36 | * Dcache aliasing issue. The writes will be forwarded to the write buffer, |
| 37 | * and merged as appropriate. |
| 38 | * |
| 39 | * Note: We rely on all ARMv4 processors implementing the "invalidate D line" |
| 40 | * instruction. If your processor does not supply this, you have to write your |
| 41 | * own copy_user_highpage that does the right thing. |
| 42 | */ |
| 43 | static void __naked |
| 44 | mc_copy_user_page(void *from, void *to) |
| 45 | { |
| 46 | asm volatile( |
| 47 | "stmfd sp!, {r4, lr} @ 2\n\ |
| 48 | mov r4, %2 @ 1\n\ |
| 49 | ldmia %0!, {r2, r3, ip, lr} @ 4\n\ |
| 50 | 1: mcr p15, 0, %1, c7, c6, 1 @ 1 invalidate D line\n\ |
| 51 | stmia %1!, {r2, r3, ip, lr} @ 4\n\ |
| 52 | ldmia %0!, {r2, r3, ip, lr} @ 4+1\n\ |
| 53 | stmia %1!, {r2, r3, ip, lr} @ 4\n\ |
| 54 | ldmia %0!, {r2, r3, ip, lr} @ 4\n\ |
| 55 | mcr p15, 0, %1, c7, c6, 1 @ 1 invalidate D line\n\ |
| 56 | stmia %1!, {r2, r3, ip, lr} @ 4\n\ |
| 57 | ldmia %0!, {r2, r3, ip, lr} @ 4\n\ |
| 58 | subs r4, r4, #1 @ 1\n\ |
| 59 | stmia %1!, {r2, r3, ip, lr} @ 4\n\ |
| 60 | ldmneia %0!, {r2, r3, ip, lr} @ 4\n\ |
| 61 | bne 1b @ 1\n\ |
| 62 | ldmfd sp!, {r4, pc} @ 3" |
| 63 | : |
| 64 | : "r" (from), "r" (to), "I" (PAGE_SIZE / 64)); |
| 65 | } |
| 66 | |
| 67 | void v4_mc_copy_user_highpage(struct page *to, struct page *from, |
| 68 | unsigned long vaddr, struct vm_area_struct *vma) |
| 69 | { |
| 70 | void *kto = kmap_atomic(to); |
| 71 | |
| 72 | if (!test_and_set_bit(PG_dcache_clean, &from->flags)) |
| 73 | __flush_dcache_page(page_mapping(from), from); |
| 74 | |
| 75 | raw_spin_lock(&minicache_lock); |
| 76 | |
| 77 | set_top_pte(COPYPAGE_MINICACHE, mk_pte(from, minicache_pgprot)); |
| 78 | |
| 79 | mc_copy_user_page((void *)COPYPAGE_MINICACHE, kto); |
| 80 | |
| 81 | raw_spin_unlock(&minicache_lock); |
| 82 | |
| 83 | kunmap_atomic(kto); |
| 84 | } |
| 85 | |
| 86 | /* |
| 87 | * ARMv4 optimised clear_user_page |
| 88 | */ |
| 89 | void v4_mc_clear_user_highpage(struct page *page, unsigned long vaddr) |
| 90 | { |
| 91 | void *ptr, *kaddr = kmap_atomic(page); |
| 92 | asm volatile("\ |
| 93 | mov r1, %2 @ 1\n\ |
| 94 | mov r2, #0 @ 1\n\ |
| 95 | mov r3, #0 @ 1\n\ |
| 96 | mov ip, #0 @ 1\n\ |
| 97 | mov lr, #0 @ 1\n\ |
| 98 | 1: mcr p15, 0, %0, c7, c6, 1 @ 1 invalidate D line\n\ |
| 99 | stmia %0!, {r2, r3, ip, lr} @ 4\n\ |
| 100 | stmia %0!, {r2, r3, ip, lr} @ 4\n\ |
| 101 | mcr p15, 0, %0, c7, c6, 1 @ 1 invalidate D line\n\ |
| 102 | stmia %0!, {r2, r3, ip, lr} @ 4\n\ |
| 103 | stmia %0!, {r2, r3, ip, lr} @ 4\n\ |
| 104 | subs r1, r1, #1 @ 1\n\ |
| 105 | bne 1b @ 1" |
| 106 | : "=r" (ptr) |
| 107 | : "0" (kaddr), "I" (PAGE_SIZE / 64) |
| 108 | : "r1", "r2", "r3", "ip", "lr"); |
| 109 | kunmap_atomic(kaddr); |
| 110 | } |
| 111 | |
| 112 | struct cpu_user_fns v4_mc_user_fns __initdata = { |
| 113 | .cpu_clear_user_highpage = v4_mc_clear_user_highpage, |
| 114 | .cpu_copy_user_highpage = v4_mc_copy_user_highpage, |
| 115 | }; |