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/*
* linux/arch/cris/mm/fault.c
*
* Low level bus fault handler
*
*
* Copyright (C) 2000, 2001 Axis Communications AB
*
* Authors: Bjorn Wesen
*
*/
#include <linux/mm.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/arch/svinto.h>
/* debug of low-level TLB reload */
#undef DEBUG
#ifdef DEBUG
#define D(x) x
#else
#define D(x)
#endif
extern volatile pgd_t *current_pgd;
extern const struct exception_table_entry
*search_exception_tables(unsigned long addr);
asmlinkage void do_page_fault(unsigned long address, struct pt_regs *regs,
int protection, int writeaccess);
/* fast TLB-fill fault handler
* this is called from entry.S with interrupts disabled
*/
void
handle_mmu_bus_fault(struct pt_regs *regs)
{
int cause;
int select;
#ifdef DEBUG
int index;
int page_id;
int acc, inv;
#endif
pgd_t* pgd = (pgd_t*)current_pgd;
pmd_t *pmd;
pte_t pte;
int miss, we, writeac;
unsigned long address;
unsigned long flags;
cause = *R_MMU_CAUSE;
address = cause & PAGE_MASK; /* get faulting address */
select = *R_TLB_SELECT;
#ifdef DEBUG
page_id = IO_EXTRACT(R_MMU_CAUSE, page_id, cause);
acc = IO_EXTRACT(R_MMU_CAUSE, acc_excp, cause);
inv = IO_EXTRACT(R_MMU_CAUSE, inv_excp, cause);
index = IO_EXTRACT(R_TLB_SELECT, index, select);
#endif
miss = IO_EXTRACT(R_MMU_CAUSE, miss_excp, cause);
we = IO_EXTRACT(R_MMU_CAUSE, we_excp, cause);
writeac = IO_EXTRACT(R_MMU_CAUSE, wr_rd, cause);
D(printk("bus_fault from IRP 0x%lx: addr 0x%lx, miss %d, inv %d, we %d, acc %d, dx %d pid %d\n",
regs->irp, address, miss, inv, we, acc, index, page_id));
/* leave it to the MM system fault handler */
if (miss)
do_page_fault(address, regs, 0, writeac);
else
do_page_fault(address, regs, 1, we);
/* Reload TLB with new entry to avoid an extra miss exception.
* do_page_fault may have flushed the TLB so we have to restore
* the MMU registers.
*/
local_save_flags(flags);
local_irq_disable();
pmd = (pmd_t *)(pgd + pgd_index(address));
if (pmd_none(*pmd))
return;
pte = *pte_offset_kernel(pmd, address);
if (!pte_present(pte))
return;
*R_TLB_SELECT = select;
*R_TLB_HI = cause;
*R_TLB_LO = pte_val(pte);
local_irq_restore(flags);
}
/* Called from arch/cris/mm/fault.c to find fixup code. */
int
find_fixup_code(struct pt_regs *regs)
{
const struct exception_table_entry *fixup;
if ((fixup = search_exception_tables(regs->irp)) != 0) {
/* Adjust the instruction pointer in the stackframe. */
regs->irp = fixup->fixup;
/*
* Don't return by restoring the CPU state, so switch
* frame-type.
*/
regs->frametype = CRIS_FRAME_NORMAL;
return 1;
}
return 0;
}
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