1 /*
2 * TLB miss handler for SH with an MMU.
3 *
4 * Copyright (C) 1999 Niibe Yutaka
5 * Copyright (C) 2003 - 2012 Paul Mundt
6 *
7 * This file is subject to the terms and conditions of the GNU General Public
8 * License. See the file "COPYING" in the main directory of this archive
9 * for more details.
10 */
11 #include <linux/kernel.h>
12 #include <linux/mm.h>
13 #include <linux/kprobes.h>
14 #include <linux/kdebug.h>
15 #include <asm/mmu_context.h>
16 #include <asm/thread_info.h>
17
18 /*
19 * Called with interrupts disabled.
20 */
21 asmlinkage int __kprobes
handle_tlbmiss(struct pt_regs * regs,unsigned long error_code,unsigned long address)22 handle_tlbmiss(struct pt_regs *regs, unsigned long error_code,
23 unsigned long address)
24 {
25 pgd_t *pgd;
26 p4d_t *p4d;
27 pud_t *pud;
28 pmd_t *pmd;
29 pte_t *pte;
30 pte_t entry;
31
32 /*
33 * We don't take page faults for P1, P2, and parts of P4, these
34 * are always mapped, whether it be due to legacy behaviour in
35 * 29-bit mode, or due to PMB configuration in 32-bit mode.
36 */
37 if (address >= P3SEG && address < P3_ADDR_MAX) {
38 pgd = pgd_offset_k(address);
39 } else {
40 if (unlikely(address >= TASK_SIZE || !current->mm))
41 return 1;
42
43 pgd = pgd_offset(current->mm, address);
44 }
45
46 p4d = p4d_offset(pgd, address);
47 if (p4d_none_or_clear_bad(p4d))
48 return 1;
49 pud = pud_offset(p4d, address);
50 if (pud_none_or_clear_bad(pud))
51 return 1;
52 pmd = pmd_offset(pud, address);
53 if (pmd_none_or_clear_bad(pmd))
54 return 1;
55 pte = pte_offset_kernel(pmd, address);
56 entry = *pte;
57 if (unlikely(pte_none(entry) || pte_not_present(entry)))
58 return 1;
59 if (unlikely(error_code && !pte_write(entry)))
60 return 1;
61
62 if (error_code)
63 entry = pte_mkdirty(entry);
64 entry = pte_mkyoung(entry);
65
66 set_pte(pte, entry);
67
68 #if defined(CONFIG_CPU_SH4) && !defined(CONFIG_SMP)
69 /*
70 * SH-4 does not set MMUCR.RC to the corresponding TLB entry in
71 * the case of an initial page write exception, so we need to
72 * flush it in order to avoid potential TLB entry duplication.
73 */
74 if (error_code == FAULT_CODE_INITIAL)
75 local_flush_tlb_one(get_asid(), address & PAGE_MASK);
76 #endif
77
78 set_thread_fault_code(error_code);
79 update_mmu_cache(NULL, address, pte);
80
81 return 0;
82 }
83