86 lines
2.2 KiB
C
86 lines
2.2 KiB
C
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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* linux/arch/arm/mm/copypage-v4wt.S
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*
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* Copyright (C) 1995-1999 Russell King
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*
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* This is for CPUs with a writethrough cache and 'flush ID cache' is
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* the only supported cache operation.
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*/
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#include <linux/init.h>
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#include <linux/highmem.h>
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/*
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* ARMv4 optimised copy_user_highpage
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*
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* Since we have writethrough caches, we don't have to worry about
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* dirty data in the cache. However, we do have to ensure that
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* subsequent reads are up to date.
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*/
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static void v4wt_copy_user_page(void *kto, const void *kfrom)
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{
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int tmp;
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asm volatile ("\
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.syntax unified\n\
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ldmia %1!, {r3, r4, ip, lr} @ 4\n\
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1: stmia %0!, {r3, r4, ip, lr} @ 4\n\
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ldmia %1!, {r3, r4, ip, lr} @ 4+1\n\
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stmia %0!, {r3, r4, ip, lr} @ 4\n\
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ldmia %1!, {r3, r4, ip, lr} @ 4\n\
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stmia %0!, {r3, r4, ip, lr} @ 4\n\
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ldmia %1!, {r3, r4, ip, lr} @ 4\n\
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subs %2, %2, #1 @ 1\n\
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stmia %0!, {r3, r4, ip, lr} @ 4\n\
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ldmiane %1!, {r3, r4, ip, lr} @ 4\n\
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bne 1b @ 1\n\
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mcr p15, 0, %2, c7, c7, 0 @ flush ID cache"
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: "+&r" (kto), "+&r" (kfrom), "=&r" (tmp)
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: "2" (PAGE_SIZE / 64)
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: "r3", "r4", "ip", "lr");
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}
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void v4wt_copy_user_highpage(struct page *to, struct page *from,
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unsigned long vaddr, struct vm_area_struct *vma)
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{
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void *kto, *kfrom;
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kto = kmap_atomic(to);
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kfrom = kmap_atomic(from);
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v4wt_copy_user_page(kto, kfrom);
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kunmap_atomic(kfrom);
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kunmap_atomic(kto);
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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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* Same story as above.
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*/
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void v4wt_clear_user_highpage(struct page *page, unsigned long vaddr)
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{
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void *ptr, *kaddr = kmap_atomic(page);
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asm volatile("\
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mov r1, %2 @ 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: stmia %0!, {r2, r3, ip, lr} @ 4\n\
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stmia %0!, {r2, r3, ip, lr} @ 4\n\
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stmia %0!, {r2, r3, ip, lr} @ 4\n\
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stmia %0!, {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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mcr p15, 0, r2, c7, c7, 0 @ flush ID cache"
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: "=r" (ptr)
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: "0" (kaddr), "I" (PAGE_SIZE / 64)
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: "r1", "r2", "r3", "ip", "lr");
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kunmap_atomic(kaddr);
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}
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struct cpu_user_fns v4wt_user_fns __initdata = {
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.cpu_clear_user_highpage = v4wt_clear_user_highpage,
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.cpu_copy_user_highpage = v4wt_copy_user_highpage,
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};
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