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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 | /* * linux/arch/arm/lib/copypage-armv4mc.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 <asm/page.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 minicache_pgprot __pgprot(L_PTE_PRESENT | L_PTE_YOUNG | \ L_PTE_MT_MINICACHE) static DEFINE_SPINLOCK(minicache_lock); /* * ARMv4 mini-dcache optimised copy_user_page * * 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. * * Note: We rely on all ARMv4 processors implementing the "invalidate D line" * instruction. If your processor does not supply this, you have to write your * own copy_user_page that does the right thing. */ static void __attribute__((naked)) mc_copy_user_page(void *from, void *to) { asm volatile( "stmfd sp!, {r4, lr} @ 2\n\ mov r4, %2 @ 1\n\ ldmia %0!, {r2, r3, ip, lr} @ 4\n\ 1: mcr p15, 0, %1, c7, c6, 1 @ 1 invalidate D line\n\ stmia %1!, {r2, r3, ip, lr} @ 4\n\ ldmia %0!, {r2, r3, ip, lr} @ 4+1\n\ stmia %1!, {r2, r3, ip, lr} @ 4\n\ ldmia %0!, {r2, r3, ip, lr} @ 4\n\ mcr p15, 0, %1, c7, c6, 1 @ 1 invalidate D line\n\ stmia %1!, {r2, r3, ip, lr} @ 4\n\ ldmia %0!, {r2, r3, ip, lr} @ 4\n\ subs r4, r4, #1 @ 1\n\ stmia %1!, {r2, r3, ip, lr} @ 4\n\ ldmneia %0!, {r2, r3, ip, lr} @ 4\n\ bne 1b @ 1\n\ ldmfd sp!, {r4, pc} @ 3" : : "r" (from), "r" (to), "I" (PAGE_SIZE / 64)); } void v4_mc_copy_user_page(void *kto, const void *kfrom, unsigned long vaddr) { struct page *page = virt_to_page(kfrom); if (test_and_clear_bit(PG_dcache_dirty, &page->flags)) __flush_dcache_page(page_mapping(page), page); spin_lock(&minicache_lock); set_pte_ext(TOP_PTE(0xffff8000), pfn_pte(__pa(kfrom) >> PAGE_SHIFT, minicache_pgprot), 0); flush_tlb_kernel_page(0xffff8000); mc_copy_user_page((void *)0xffff8000, kto); spin_unlock(&minicache_lock); } /* * ARMv4 optimised clear_user_page */ void __attribute__((naked)) v4_mc_clear_user_page(void *kaddr, unsigned long vaddr) { asm volatile( "str lr, [sp, #-4]!\n\ mov r1, %0 @ 1\n\ mov r2, #0 @ 1\n\ mov r3, #0 @ 1\n\ mov ip, #0 @ 1\n\ mov lr, #0 @ 1\n\ 1: mcr p15, 0, r0, c7, c6, 1 @ 1 invalidate D line\n\ stmia r0!, {r2, r3, ip, lr} @ 4\n\ stmia r0!, {r2, r3, ip, lr} @ 4\n\ mcr p15, 0, r0, c7, c6, 1 @ 1 invalidate D line\n\ stmia r0!, {r2, r3, ip, lr} @ 4\n\ stmia r0!, {r2, r3, ip, lr} @ 4\n\ subs r1, r1, #1 @ 1\n\ bne 1b @ 1\n\ ldr pc, [sp], #4" : : "I" (PAGE_SIZE / 64)); } struct cpu_user_fns v4_mc_user_fns __initdata = { .cpu_clear_user_page = v4_mc_clear_user_page, .cpu_copy_user_page = v4_mc_copy_user_page, }; |