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111 lines
3.3 KiB
111 lines
3.3 KiB
/*
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* linux/arch/arm/lib/copypage-armv4mc.S
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*
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* Copyright (C) 1995-2005 Russell King
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This handles the mini data cache, as found on SA11x0 and XScale
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* processors. When we copy a user page page, we map it in such a way
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* that accesses to this page will not touch the main data cache, but
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* will be cached in the mini data cache. This prevents us thrashing
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* the main data cache on page faults.
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*/
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#include <linux/init.h>
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#include <linux/mm.h>
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#include <asm/page.h>
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#include <asm/pgtable.h>
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#include <asm/tlbflush.h>
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#include "mm.h"
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/*
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* 0xffff8000 to 0xffffffff is reserved for any ARM architecture
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* specific hacks for copying pages efficiently.
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*/
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#define minicache_pgprot __pgprot(L_PTE_PRESENT | L_PTE_YOUNG | \
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L_PTE_CACHEABLE)
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static DEFINE_SPINLOCK(minicache_lock);
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/*
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* ARMv4 mini-dcache optimised copy_user_page
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*
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* We flush the destination cache lines just before we write the data into the
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* corresponding address. Since the Dcache is read-allocate, this removes the
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* Dcache aliasing issue. The writes will be forwarded to the write buffer,
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* and merged as appropriate.
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*
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* Note: We rely on all ARMv4 processors implementing the "invalidate D line"
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* instruction. If your processor does not supply this, you have to write your
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* own copy_user_page that does the right thing.
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*/
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static void __attribute__((naked))
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mc_copy_user_page(void *from, void *to)
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{
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asm volatile(
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"stmfd sp!, {r4, lr} @ 2\n\
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mov r4, %2 @ 1\n\
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ldmia %0!, {r2, r3, ip, lr} @ 4\n\
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1: mcr p15, 0, %1, c7, c6, 1 @ 1 invalidate D line\n\
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stmia %1!, {r2, r3, ip, lr} @ 4\n\
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ldmia %0!, {r2, r3, ip, lr} @ 4+1\n\
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stmia %1!, {r2, r3, ip, lr} @ 4\n\
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ldmia %0!, {r2, r3, ip, lr} @ 4\n\
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mcr p15, 0, %1, c7, c6, 1 @ 1 invalidate D line\n\
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stmia %1!, {r2, r3, ip, lr} @ 4\n\
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ldmia %0!, {r2, r3, ip, lr} @ 4\n\
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subs r4, r4, #1 @ 1\n\
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stmia %1!, {r2, r3, ip, lr} @ 4\n\
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ldmneia %0!, {r2, r3, ip, lr} @ 4\n\
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bne 1b @ 1\n\
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ldmfd sp!, {r4, pc} @ 3"
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:
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: "r" (from), "r" (to), "I" (PAGE_SIZE / 64));
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}
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void v4_mc_copy_user_page(void *kto, const void *kfrom, unsigned long vaddr)
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{
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spin_lock(&minicache_lock);
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set_pte(TOP_PTE(0xffff8000), pfn_pte(__pa(kfrom) >> PAGE_SHIFT, minicache_pgprot));
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flush_tlb_kernel_page(0xffff8000);
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mc_copy_user_page((void *)0xffff8000, kto);
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spin_unlock(&minicache_lock);
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}
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/*
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* ARMv4 optimised clear_user_page
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*/
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void __attribute__((naked))
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v4_mc_clear_user_page(void *kaddr, unsigned long vaddr)
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{
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asm volatile(
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"str lr, [sp, #-4]!\n\
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mov r1, %0 @ 1\n\
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mov r2, #0 @ 1\n\
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mov r3, #0 @ 1\n\
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mov ip, #0 @ 1\n\
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mov lr, #0 @ 1\n\
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1: mcr p15, 0, r0, c7, c6, 1 @ 1 invalidate D line\n\
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stmia r0!, {r2, r3, ip, lr} @ 4\n\
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stmia r0!, {r2, r3, ip, lr} @ 4\n\
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mcr p15, 0, r0, c7, c6, 1 @ 1 invalidate D line\n\
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stmia r0!, {r2, r3, ip, lr} @ 4\n\
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stmia r0!, {r2, r3, ip, lr} @ 4\n\
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subs r1, r1, #1 @ 1\n\
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bne 1b @ 1\n\
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ldr pc, [sp], #4"
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:
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: "I" (PAGE_SIZE / 64));
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}
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struct cpu_user_fns v4_mc_user_fns __initdata = {
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.cpu_clear_user_page = v4_mc_clear_user_page,
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.cpu_copy_user_page = v4_mc_copy_user_page,
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};
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