Chen Liqin | 6bc9a39 | 2009-06-12 22:01:00 +0800 | [diff] [blame] | 1 | /* |
| 2 | * arch/score/mm/fault.c |
| 3 | * |
| 4 | * Score Processor version. |
| 5 | * |
| 6 | * Copyright (C) 2009 Sunplus Core Technology Co., Ltd. |
| 7 | * Lennox Wu <lennox.wu@sunplusct.com> |
| 8 | * Chen Liqin <liqin.chen@sunplusct.com> |
| 9 | * |
| 10 | * This program is free software; you can redistribute it and/or modify |
| 11 | * it under the terms of the GNU General Public License as published by |
| 12 | * the Free Software Foundation; either version 2 of the License, or |
| 13 | * (at your option) any later version. |
| 14 | * |
| 15 | * This program is distributed in the hope that it will be useful, |
| 16 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 18 | * GNU General Public License for more details. |
| 19 | * |
| 20 | * You should have received a copy of the GNU General Public License |
| 21 | * along with this program; if not, see the file COPYING, or write |
| 22 | * to the Free Software Foundation, Inc., |
| 23 | * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
| 24 | */ |
| 25 | |
| 26 | #include <linux/errno.h> |
| 27 | #include <linux/interrupt.h> |
| 28 | #include <linux/kernel.h> |
| 29 | #include <linux/mm.h> |
| 30 | #include <linux/mman.h> |
| 31 | #include <linux/module.h> |
| 32 | #include <linux/signal.h> |
| 33 | #include <linux/sched.h> |
| 34 | #include <linux/string.h> |
| 35 | #include <linux/types.h> |
| 36 | #include <linux/ptrace.h> |
David Hildenbrand | 70ffdb9 | 2015-05-11 17:52:11 +0200 | [diff] [blame] | 37 | #include <linux/uaccess.h> |
Chen Liqin | 6bc9a39 | 2009-06-12 22:01:00 +0800 | [diff] [blame] | 38 | |
| 39 | /* |
| 40 | * This routine handles page faults. It determines the address, |
| 41 | * and the problem, and then passes it off to one of the appropriate |
| 42 | * routines. |
| 43 | */ |
| 44 | asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long write, |
| 45 | unsigned long address) |
| 46 | { |
| 47 | struct vm_area_struct *vma = NULL; |
| 48 | struct task_struct *tsk = current; |
| 49 | struct mm_struct *mm = tsk->mm; |
| 50 | const int field = sizeof(unsigned long) * 2; |
Johannes Weiner | 759496b | 2013-09-12 15:13:39 -0700 | [diff] [blame] | 51 | unsigned long flags = 0; |
Chen Liqin | 6bc9a39 | 2009-06-12 22:01:00 +0800 | [diff] [blame] | 52 | siginfo_t info; |
| 53 | int fault; |
| 54 | |
| 55 | info.si_code = SEGV_MAPERR; |
| 56 | |
| 57 | /* |
| 58 | * We fault-in kernel-space virtual memory on-demand. The |
| 59 | * 'reference' page table is init_mm.pgd. |
| 60 | * |
| 61 | * NOTE! We MUST NOT take any locks for this case. We may |
| 62 | * be in an interrupt or a critical region, and should |
| 63 | * only copy the information from the master page table, |
| 64 | * nothing more. |
| 65 | */ |
| 66 | if (unlikely(address >= VMALLOC_START && address <= VMALLOC_END)) |
| 67 | goto vmalloc_fault; |
| 68 | #ifdef MODULE_START |
| 69 | if (unlikely(address >= MODULE_START && address < MODULE_END)) |
| 70 | goto vmalloc_fault; |
| 71 | #endif |
| 72 | |
| 73 | /* |
| 74 | * If we're in an interrupt or have no user |
| 75 | * context, we must not take the fault.. |
| 76 | */ |
David Hildenbrand | 70ffdb9 | 2015-05-11 17:52:11 +0200 | [diff] [blame] | 77 | if (pagefault_disabled() || !mm) |
Chen Liqin | 6bc9a39 | 2009-06-12 22:01:00 +0800 | [diff] [blame] | 78 | goto bad_area_nosemaphore; |
| 79 | |
Johannes Weiner | 759496b | 2013-09-12 15:13:39 -0700 | [diff] [blame] | 80 | if (user_mode(regs)) |
| 81 | flags |= FAULT_FLAG_USER; |
| 82 | |
Chen Liqin | 6bc9a39 | 2009-06-12 22:01:00 +0800 | [diff] [blame] | 83 | down_read(&mm->mmap_sem); |
| 84 | vma = find_vma(mm, address); |
| 85 | if (!vma) |
| 86 | goto bad_area; |
| 87 | if (vma->vm_start <= address) |
| 88 | goto good_area; |
| 89 | if (!(vma->vm_flags & VM_GROWSDOWN)) |
| 90 | goto bad_area; |
| 91 | if (expand_stack(vma, address)) |
| 92 | goto bad_area; |
| 93 | /* |
| 94 | * Ok, we have a good vm_area for this memory access, so |
| 95 | * we can handle it.. |
| 96 | */ |
| 97 | good_area: |
| 98 | info.si_code = SEGV_ACCERR; |
| 99 | |
| 100 | if (write) { |
| 101 | if (!(vma->vm_flags & VM_WRITE)) |
| 102 | goto bad_area; |
Johannes Weiner | 759496b | 2013-09-12 15:13:39 -0700 | [diff] [blame] | 103 | flags |= FAULT_FLAG_WRITE; |
Chen Liqin | 6bc9a39 | 2009-06-12 22:01:00 +0800 | [diff] [blame] | 104 | } else { |
| 105 | if (!(vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC))) |
| 106 | goto bad_area; |
| 107 | } |
| 108 | |
Chen Liqin | 6bc9a39 | 2009-06-12 22:01:00 +0800 | [diff] [blame] | 109 | /* |
| 110 | * If for any reason at all we couldn't handle the fault, |
| 111 | * make sure we exit gracefully rather than endlessly redo |
| 112 | * the fault. |
| 113 | */ |
Johannes Weiner | 759496b | 2013-09-12 15:13:39 -0700 | [diff] [blame] | 114 | fault = handle_mm_fault(mm, vma, address, flags); |
Chen Liqin | 6bc9a39 | 2009-06-12 22:01:00 +0800 | [diff] [blame] | 115 | if (unlikely(fault & VM_FAULT_ERROR)) { |
| 116 | if (fault & VM_FAULT_OOM) |
| 117 | goto out_of_memory; |
Linus Torvalds | 33692f2 | 2015-01-29 10:51:32 -0800 | [diff] [blame] | 118 | else if (fault & VM_FAULT_SIGSEGV) |
| 119 | goto bad_area; |
Chen Liqin | 6bc9a39 | 2009-06-12 22:01:00 +0800 | [diff] [blame] | 120 | else if (fault & VM_FAULT_SIGBUS) |
| 121 | goto do_sigbus; |
| 122 | BUG(); |
| 123 | } |
| 124 | if (fault & VM_FAULT_MAJOR) |
| 125 | tsk->maj_flt++; |
| 126 | else |
| 127 | tsk->min_flt++; |
| 128 | |
| 129 | up_read(&mm->mmap_sem); |
| 130 | return; |
| 131 | |
| 132 | /* |
| 133 | * Something tried to access memory that isn't in our memory map.. |
| 134 | * Fix it, but check if it's kernel or user first.. |
| 135 | */ |
| 136 | bad_area: |
| 137 | up_read(&mm->mmap_sem); |
| 138 | |
| 139 | bad_area_nosemaphore: |
| 140 | /* User mode accesses just cause a SIGSEGV */ |
| 141 | if (user_mode(regs)) { |
| 142 | tsk->thread.cp0_badvaddr = address; |
| 143 | tsk->thread.error_code = write; |
| 144 | info.si_signo = SIGSEGV; |
| 145 | info.si_errno = 0; |
| 146 | /* info.si_code has been set above */ |
| 147 | info.si_addr = (void __user *) address; |
| 148 | force_sig_info(SIGSEGV, &info, tsk); |
| 149 | return; |
| 150 | } |
| 151 | |
| 152 | no_context: |
| 153 | /* Are we prepared to handle this kernel fault? */ |
| 154 | if (fixup_exception(regs)) { |
| 155 | current->thread.cp0_baduaddr = address; |
| 156 | return; |
| 157 | } |
| 158 | |
| 159 | /* |
| 160 | * Oops. The kernel tried to access some bad page. We'll have to |
| 161 | * terminate things with extreme prejudice. |
| 162 | */ |
| 163 | bust_spinlocks(1); |
| 164 | |
| 165 | printk(KERN_ALERT "CPU %d Unable to handle kernel paging request at " |
| 166 | "virtual address %0*lx, epc == %0*lx, ra == %0*lx\n", |
| 167 | 0, field, address, field, regs->cp0_epc, |
| 168 | field, regs->regs[3]); |
| 169 | die("Oops", regs); |
| 170 | |
| 171 | /* |
| 172 | * We ran out of memory, or some other thing happened to us that made |
| 173 | * us unable to handle the page fault gracefully. |
| 174 | */ |
| 175 | out_of_memory: |
| 176 | up_read(&mm->mmap_sem); |
Johannes Weiner | 609838c | 2013-07-08 15:59:50 -0700 | [diff] [blame] | 177 | if (!user_mode(regs)) |
| 178 | goto no_context; |
| 179 | pagefault_out_of_memory(); |
| 180 | return; |
Chen Liqin | 6bc9a39 | 2009-06-12 22:01:00 +0800 | [diff] [blame] | 181 | |
| 182 | do_sigbus: |
| 183 | up_read(&mm->mmap_sem); |
| 184 | /* Kernel mode? Handle exceptions or die */ |
| 185 | if (!user_mode(regs)) |
| 186 | goto no_context; |
| 187 | else |
| 188 | /* |
| 189 | * Send a sigbus, regardless of whether we were in kernel |
| 190 | * or user mode. |
| 191 | */ |
| 192 | tsk->thread.cp0_badvaddr = address; |
| 193 | info.si_signo = SIGBUS; |
| 194 | info.si_errno = 0; |
| 195 | info.si_code = BUS_ADRERR; |
| 196 | info.si_addr = (void __user *) address; |
| 197 | force_sig_info(SIGBUS, &info, tsk); |
| 198 | return; |
| 199 | vmalloc_fault: |
| 200 | { |
| 201 | /* |
| 202 | * Synchronize this task's top level page-table |
| 203 | * with the 'reference' page table. |
| 204 | * |
| 205 | * Do _not_ use "tsk" here. We might be inside |
| 206 | * an interrupt in the middle of a task switch.. |
| 207 | */ |
| 208 | int offset = __pgd_offset(address); |
| 209 | pgd_t *pgd, *pgd_k; |
| 210 | pud_t *pud, *pud_k; |
| 211 | pmd_t *pmd, *pmd_k; |
| 212 | pte_t *pte_k; |
| 213 | |
| 214 | pgd = (pgd_t *) pgd_current + offset; |
| 215 | pgd_k = init_mm.pgd + offset; |
| 216 | |
| 217 | if (!pgd_present(*pgd_k)) |
| 218 | goto no_context; |
| 219 | set_pgd(pgd, *pgd_k); |
| 220 | |
| 221 | pud = pud_offset(pgd, address); |
| 222 | pud_k = pud_offset(pgd_k, address); |
| 223 | if (!pud_present(*pud_k)) |
| 224 | goto no_context; |
| 225 | |
| 226 | pmd = pmd_offset(pud, address); |
| 227 | pmd_k = pmd_offset(pud_k, address); |
| 228 | if (!pmd_present(*pmd_k)) |
| 229 | goto no_context; |
| 230 | set_pmd(pmd, *pmd_k); |
| 231 | |
| 232 | pte_k = pte_offset_kernel(pmd_k, address); |
| 233 | if (!pte_present(*pte_k)) |
| 234 | goto no_context; |
| 235 | return; |
| 236 | } |
| 237 | } |