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446c92b290
This is a fix for the following crash observed in 2.6.29-rc3: http://lkml.org/lkml/2009/1/29/150 On ARM it doesn't make sense to trace a naked function because then mcount is called without stack and frame pointer being set up and there is no chance to restore the lr register to the value before mcount was called. Reported-by: Matthias Kaehlcke <matthias@kaehlcke.net> Tested-by: Matthias Kaehlcke <matthias@kaehlcke.net> Cc: Abhishek Sagar <sagar.abhishek@gmail.com> Cc: Steven Rostedt <rostedt@home.goodmis.org> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
143 lines
3.8 KiB
C
143 lines
3.8 KiB
C
/*
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* linux/arch/arm/lib/copypage-xscale.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 <linux/highmem.h>
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#include <asm/pgtable.h>
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#include <asm/tlbflush.h>
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#include <asm/cacheflush.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 COPYPAGE_MINICACHE 0xffff8000
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#define minicache_pgprot __pgprot(L_PTE_PRESENT | L_PTE_YOUNG | \
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L_PTE_MT_MINICACHE)
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static DEFINE_SPINLOCK(minicache_lock);
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/*
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* XScale mini-dcache optimised copy_user_highpage
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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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static void __naked
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mc_copy_user_page(void *from, void *to)
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{
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/*
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* Strangely enough, best performance is achieved
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* when prefetching destination as well. (NP)
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*/
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asm volatile(
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"stmfd sp!, {r4, r5, lr} \n\
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mov lr, %2 \n\
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pld [r0, #0] \n\
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pld [r0, #32] \n\
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pld [r1, #0] \n\
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pld [r1, #32] \n\
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1: pld [r0, #64] \n\
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pld [r0, #96] \n\
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pld [r1, #64] \n\
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pld [r1, #96] \n\
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2: ldrd r2, [r0], #8 \n\
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ldrd r4, [r0], #8 \n\
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mov ip, r1 \n\
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strd r2, [r1], #8 \n\
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ldrd r2, [r0], #8 \n\
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strd r4, [r1], #8 \n\
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ldrd r4, [r0], #8 \n\
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strd r2, [r1], #8 \n\
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strd r4, [r1], #8 \n\
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mcr p15, 0, ip, c7, c10, 1 @ clean D line\n\
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ldrd r2, [r0], #8 \n\
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mcr p15, 0, ip, c7, c6, 1 @ invalidate D line\n\
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ldrd r4, [r0], #8 \n\
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mov ip, r1 \n\
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strd r2, [r1], #8 \n\
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ldrd r2, [r0], #8 \n\
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strd r4, [r1], #8 \n\
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ldrd r4, [r0], #8 \n\
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strd r2, [r1], #8 \n\
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strd r4, [r1], #8 \n\
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mcr p15, 0, ip, c7, c10, 1 @ clean D line\n\
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subs lr, lr, #1 \n\
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mcr p15, 0, ip, c7, c6, 1 @ invalidate D line\n\
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bgt 1b \n\
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beq 2b \n\
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ldmfd sp!, {r4, r5, pc} "
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:
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: "r" (from), "r" (to), "I" (PAGE_SIZE / 64 - 1));
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}
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void xscale_mc_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 = kmap_atomic(to, KM_USER1);
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if (test_and_clear_bit(PG_dcache_dirty, &from->flags))
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__flush_dcache_page(page_mapping(from), from);
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spin_lock(&minicache_lock);
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set_pte_ext(TOP_PTE(COPYPAGE_MINICACHE), pfn_pte(page_to_pfn(from), minicache_pgprot), 0);
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flush_tlb_kernel_page(COPYPAGE_MINICACHE);
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mc_copy_user_page((void *)COPYPAGE_MINICACHE, kto);
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spin_unlock(&minicache_lock);
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kunmap_atomic(kto, KM_USER1);
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}
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/*
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* XScale optimised clear_user_page
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*/
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void
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xscale_mc_clear_user_highpage(struct page *page, unsigned long vaddr)
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{
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void *ptr, *kaddr = kmap_atomic(page, KM_USER0);
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asm volatile(
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"mov r1, %2 \n\
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mov r2, #0 \n\
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mov r3, #0 \n\
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1: mov ip, %0 \n\
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strd r2, [%0], #8 \n\
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strd r2, [%0], #8 \n\
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strd r2, [%0], #8 \n\
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strd r2, [%0], #8 \n\
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mcr p15, 0, ip, c7, c10, 1 @ clean D line\n\
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subs r1, r1, #1 \n\
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mcr p15, 0, ip, c7, c6, 1 @ invalidate D line\n\
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bne 1b"
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: "=r" (ptr)
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: "0" (kaddr), "I" (PAGE_SIZE / 32)
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: "r1", "r2", "r3", "ip");
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kunmap_atomic(kaddr, KM_USER0);
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}
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struct cpu_user_fns xscale_mc_user_fns __initdata = {
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.cpu_clear_user_highpage = xscale_mc_clear_user_highpage,
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.cpu_copy_user_highpage = xscale_mc_copy_user_highpage,
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};
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