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>
121 lines
3.6 KiB
C
121 lines
3.6 KiB
C
/*
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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 <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 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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* ARMv4 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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* 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_highpage that does the right thing.
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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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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_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(0xffff8000), pfn_pte(page_to_pfn(from), minicache_pgprot), 0);
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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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kunmap_atomic(kto, KM_USER1);
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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 v4_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 @ 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, %0, c7, c6, 1 @ 1 invalidate D line\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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mcr p15, 0, %0, c7, c6, 1 @ 1 invalidate D line\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"
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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, KM_USER0);
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}
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struct cpu_user_fns v4_mc_user_fns __initdata = {
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.cpu_clear_user_highpage = v4_mc_clear_user_highpage,
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.cpu_copy_user_highpage = v4_mc_copy_user_highpage,
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};
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