1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * linux/arch/cris/mm/fault.c
4 *
5 * Low level bus fault handler
6 *
7 *
8 * Copyright (C) 2000-2007 Axis Communications AB
9 *
10 * Authors: Bjorn Wesen
11 *
12 */
13
14 #include <linux/mm.h>
15 #include <linux/uaccess.h>
16 #include <asm/pgtable.h>
17 #include <arch/svinto.h>
18 #include <asm/mmu_context.h>
19
20 /* debug of low-level TLB reload */
21 #undef DEBUG
22
23 #ifdef DEBUG
24 #define D(x) x
25 #else
26 #define D(x)
27 #endif
28
29 extern const struct exception_table_entry
30 *search_exception_tables(unsigned long addr);
31
32 asmlinkage void do_page_fault(unsigned long address, struct pt_regs *regs,
33 int protection, int writeaccess);
34
35 /* fast TLB-fill fault handler
36 * this is called from entry.S with interrupts disabled
37 */
38
39 void
handle_mmu_bus_fault(struct pt_regs * regs)40 handle_mmu_bus_fault(struct pt_regs *regs)
41 {
42 int cause;
43 int select;
44 #ifdef DEBUG
45 int index;
46 int page_id;
47 int acc, inv;
48 #endif
49 pgd_t* pgd = (pgd_t*)per_cpu(current_pgd, smp_processor_id());
50 pmd_t *pmd;
51 pte_t pte;
52 int miss, we, writeac;
53 unsigned long address;
54 unsigned long flags;
55
56 cause = *R_MMU_CAUSE;
57
58 address = cause & PAGE_MASK; /* get faulting address */
59 select = *R_TLB_SELECT;
60
61 #ifdef DEBUG
62 page_id = IO_EXTRACT(R_MMU_CAUSE, page_id, cause);
63 acc = IO_EXTRACT(R_MMU_CAUSE, acc_excp, cause);
64 inv = IO_EXTRACT(R_MMU_CAUSE, inv_excp, cause);
65 index = IO_EXTRACT(R_TLB_SELECT, index, select);
66 #endif
67 miss = IO_EXTRACT(R_MMU_CAUSE, miss_excp, cause);
68 we = IO_EXTRACT(R_MMU_CAUSE, we_excp, cause);
69 writeac = IO_EXTRACT(R_MMU_CAUSE, wr_rd, cause);
70
71 D(printk("bus_fault from IRP 0x%lx: addr 0x%lx, miss %d, inv %d, we %d, acc %d, dx %d pid %d\n",
72 regs->irp, address, miss, inv, we, acc, index, page_id));
73
74 /* leave it to the MM system fault handler */
75 if (miss)
76 do_page_fault(address, regs, 0, writeac);
77 else
78 do_page_fault(address, regs, 1, we);
79
80 /* Reload TLB with new entry to avoid an extra miss exception.
81 * do_page_fault may have flushed the TLB so we have to restore
82 * the MMU registers.
83 */
84 local_irq_save(flags);
85 pmd = (pmd_t *)(pgd + pgd_index(address));
86 if (pmd_none(*pmd))
87 goto exit;
88 pte = *pte_offset_kernel(pmd, address);
89 if (!pte_present(pte))
90 goto exit;
91 *R_TLB_SELECT = select;
92 *R_TLB_HI = cause;
93 *R_TLB_LO = pte_val(pte);
94 exit:
95 local_irq_restore(flags);
96 }
97