063b0a4207
We used to override the copy_user_page() function. However, this is not only inefficient, it also causes additional complexity for highmem support, since we convert from a struct page to a kernel direct mapped address and back to a struct page again. Moreover, with highmem support, we end up pointlessly setting up kmap entries for pages which we're going to remap. So, push the kmapping down into the copypage implementation files where it's required. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
88 lines
2.3 KiB
C
88 lines
2.3 KiB
C
/*
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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 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 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 __attribute__((naked))
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v4wt_copy_user_page(void *kto, const void *kfrom)
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{
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asm("\
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stmfd sp!, {r4, lr} @ 2\n\
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mov r2, %0 @ 1\n\
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ldmia r1!, {r3, r4, ip, lr} @ 4\n\
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1: stmia r0!, {r3, r4, ip, lr} @ 4\n\
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ldmia r1!, {r3, r4, ip, lr} @ 4+1\n\
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stmia r0!, {r3, r4, ip, lr} @ 4\n\
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ldmia r1!, {r3, r4, ip, lr} @ 4\n\
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stmia r0!, {r3, r4, ip, lr} @ 4\n\
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ldmia r1!, {r3, r4, ip, lr} @ 4\n\
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subs r2, r2, #1 @ 1\n\
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stmia r0!, {r3, r4, ip, lr} @ 4\n\
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ldmneia r1!, {r3, r4, ip, lr} @ 4\n\
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bne 1b @ 1\n\
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mcr p15, 0, r2, c7, c7, 0 @ flush ID cache\n\
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ldmfd sp!, {r4, pc} @ 3"
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:
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: "I" (PAGE_SIZE / 64));
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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)
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{
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void *kto, *kfrom;
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kto = kmap_atomic(to, KM_USER0);
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kfrom = kmap_atomic(from, KM_USER1);
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v4wt_copy_user_page(kto, kfrom);
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kunmap_atomic(kfrom, KM_USER1);
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kunmap_atomic(kto, KM_USER0);
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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 __attribute__((naked))
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v4wt_clear_user_page(void *kaddr, unsigned long vaddr)
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{
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asm("\
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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: stmia r0!, {r2, r3, ip, lr} @ 4\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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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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mcr p15, 0, r2, c7, c7, 0 @ flush ID cache\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 v4wt_user_fns __initdata = {
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.cpu_clear_user_page = v4wt_clear_user_page,
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.cpu_copy_user_highpage = v4wt_copy_user_highpage,
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};
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