Commit | Line | Data |
---|---|---|
d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
fbd7053a VG |
2 | /* Page Fault Handling for ARC (TLB Miss / ProtV) |
3 | * | |
4 | * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) | |
fbd7053a VG |
5 | */ |
6 | ||
7 | #include <linux/signal.h> | |
8 | #include <linux/interrupt.h> | |
3f07c014 | 9 | #include <linux/sched/signal.h> |
fbd7053a VG |
10 | #include <linux/errno.h> |
11 | #include <linux/ptrace.h> | |
fbd7053a VG |
12 | #include <linux/uaccess.h> |
13 | #include <linux/kdebug.h> | |
ceed97ab | 14 | #include <linux/perf_event.h> |
50a7ca3c | 15 | #include <linux/mm_types.h> |
fbd7053a | 16 | #include <asm/pgalloc.h> |
da1677b0 | 17 | #include <asm/mmu.h> |
fbd7053a | 18 | |
336e2136 VG |
19 | /* |
20 | * kernel virtual address is required to implement vmalloc/pkmap/fixmap | |
21 | * Refer to asm/processor.h for System Memory Map | |
22 | * | |
23 | * It simply copies the PMD entry (pointer to 2nd level page table or hugepage) | |
24 | * from swapper pgdir to task pgdir. The 2nd level table/page is thus shared | |
25 | */ | |
26 | noinline static int handle_kernel_vaddr_fault(unsigned long address) | |
fbd7053a VG |
27 | { |
28 | /* | |
29 | * Synchronize this task's top level page-table | |
30 | * with the 'reference' page table. | |
31 | */ | |
32 | pgd_t *pgd, *pgd_k; | |
33 | pud_t *pud, *pud_k; | |
34 | pmd_t *pmd, *pmd_k; | |
35 | ||
9c41f4ee | 36 | pgd = pgd_offset_fast(current->active_mm, address); |
fbd7053a VG |
37 | pgd_k = pgd_offset_k(address); |
38 | ||
39 | if (!pgd_present(*pgd_k)) | |
40 | goto bad_area; | |
41 | ||
42 | pud = pud_offset(pgd, address); | |
43 | pud_k = pud_offset(pgd_k, address); | |
44 | if (!pud_present(*pud_k)) | |
45 | goto bad_area; | |
46 | ||
47 | pmd = pmd_offset(pud, address); | |
48 | pmd_k = pmd_offset(pud_k, address); | |
49 | if (!pmd_present(*pmd_k)) | |
50 | goto bad_area; | |
51 | ||
52 | set_pmd(pmd, *pmd_k); | |
53 | ||
54 | /* XXX: create the TLB entry here */ | |
55 | return 0; | |
56 | ||
57 | bad_area: | |
58 | return 1; | |
59 | } | |
60 | ||
21a63b56 | 61 | void do_page_fault(unsigned long address, struct pt_regs *regs) |
fbd7053a VG |
62 | { |
63 | struct vm_area_struct *vma = NULL; | |
64 | struct task_struct *tsk = current; | |
65 | struct mm_struct *mm = tsk->mm; | |
5e91bf5c | 66 | int sig, si_code = SEGV_MAPERR; |
85c5e337 | 67 | unsigned int write = 0, exec = 0, mask; |
5e91bf5c | 68 | vm_fault_t fault = VM_FAULT_SIGSEGV; /* handle_mm_fault() output */ |
02c88d14 | 69 | unsigned int flags; /* handle_mm_fault() input */ |
fbd7053a VG |
70 | |
71 | /* | |
fbd7053a VG |
72 | * NOTE! We MUST NOT take any locks for this case. We may |
73 | * be in an interrupt or a critical region, and should | |
74 | * only copy the information from the master page table, | |
75 | * nothing more. | |
76 | */ | |
a8c715b4 | 77 | if (address >= VMALLOC_START && !user_mode(regs)) { |
13e2cc12 | 78 | if (unlikely(handle_kernel_vaddr_fault(address))) |
a8c715b4 | 79 | goto no_context; |
fbd7053a VG |
80 | else |
81 | return; | |
82 | } | |
83 | ||
fbd7053a VG |
84 | /* |
85 | * If we're in an interrupt or have no user | |
86 | * context, we must not take the fault.. | |
87 | */ | |
70ffdb93 | 88 | if (faulthandler_disabled() || !mm) |
fbd7053a VG |
89 | goto no_context; |
90 | ||
85c5e337 VG |
91 | if (regs->ecr_cause & ECR_C_PROTV_STORE) /* ST/EX */ |
92 | write = 1; | |
93 | else if ((regs->ecr_vec == ECR_V_PROTV) && | |
94 | (regs->ecr_cause == ECR_C_PROTV_INST_FETCH)) | |
95 | exec = 1; | |
96 | ||
97 | flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; | |
759496ba JW |
98 | if (user_mode(regs)) |
99 | flags |= FAULT_FLAG_USER; | |
85c5e337 VG |
100 | if (write) |
101 | flags |= FAULT_FLAG_WRITE; | |
102 | ||
fbd7053a VG |
103 | retry: |
104 | down_read(&mm->mmap_sem); | |
450e5b6f | 105 | |
fbd7053a VG |
106 | vma = find_vma(mm, address); |
107 | if (!vma) | |
108 | goto bad_area; | |
450e5b6f VG |
109 | if (unlikely(address < vma->vm_start)) { |
110 | if (!(vma->vm_flags & VM_GROWSDOWN) || expand_stack(vma, address)) | |
111 | goto bad_area; | |
112 | } | |
fbd7053a VG |
113 | |
114 | /* | |
85c5e337 | 115 | * vm_area is good, now check permissions for this memory access |
fbd7053a | 116 | */ |
85c5e337 VG |
117 | mask = VM_READ; |
118 | if (write) | |
119 | mask = VM_WRITE; | |
120 | if (exec) | |
121 | mask = VM_EXEC; | |
122 | ||
123 | if (!(vma->vm_flags & mask)) { | |
124 | si_code = SEGV_ACCERR; | |
fbd7053a | 125 | goto bad_area; |
fbd7053a VG |
126 | } |
127 | ||
dcddffd4 | 128 | fault = handle_mm_fault(vma, address, flags); |
fbd7053a | 129 | |
02c88d14 VG |
130 | /* |
131 | * Fault retry nuances | |
132 | */ | |
133 | if (unlikely(fault & VM_FAULT_RETRY)) { | |
4d447455 VG |
134 | |
135 | /* | |
02c88d14 VG |
136 | * If fault needs to be retried, handle any pending signals |
137 | * first (by returning to user mode). | |
138 | * mmap_sem already relinquished by core mm for RETRY case | |
4d447455 | 139 | */ |
02c88d14 | 140 | if (fatal_signal_pending(current)) { |
4d447455 VG |
141 | if (!user_mode(regs)) |
142 | goto no_context; | |
fbd7053a | 143 | return; |
4d447455 | 144 | } |
02c88d14 VG |
145 | /* |
146 | * retry state machine | |
147 | */ | |
148 | if (flags & FAULT_FLAG_ALLOW_RETRY) { | |
149 | flags &= ~FAULT_FLAG_ALLOW_RETRY; | |
150 | flags |= FAULT_FLAG_TRIED; | |
151 | goto retry; | |
152 | } | |
fbd7053a VG |
153 | } |
154 | ||
926150db VG |
155 | bad_area: |
156 | up_read(&mm->mmap_sem); | |
157 | ||
02c88d14 VG |
158 | /* |
159 | * Major/minor page fault accounting | |
160 | * (in case of retry we only land here once) | |
161 | */ | |
ceed97ab VG |
162 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); |
163 | ||
fbd7053a | 164 | if (likely(!(fault & VM_FAULT_ERROR))) { |
02c88d14 VG |
165 | if (fault & VM_FAULT_MAJOR) { |
166 | tsk->maj_flt++; | |
167 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, | |
168 | regs, address); | |
169 | } else { | |
170 | tsk->min_flt++; | |
171 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, | |
172 | regs, address); | |
fbd7053a VG |
173 | } |
174 | ||
02c88d14 | 175 | /* Normal return path: fault Handled Gracefully */ |
fbd7053a VG |
176 | return; |
177 | } | |
178 | ||
98cb57ad VG |
179 | if (!user_mode(regs)) |
180 | goto no_context; | |
181 | ||
5e91bf5c VG |
182 | if (fault & VM_FAULT_OOM) { |
183 | pagefault_out_of_memory(); | |
184 | return; | |
185 | } | |
fbd7053a | 186 | |
5e91bf5c VG |
187 | if (fault & VM_FAULT_SIGBUS) { |
188 | sig = SIGBUS; | |
189 | si_code = BUS_ADRERR; | |
190 | } | |
191 | else { | |
192 | sig = SIGSEGV; | |
193 | } | |
fbd7053a VG |
194 | |
195 | tsk->thread.fault_address = address; | |
5e91bf5c | 196 | force_sig_fault(sig, si_code, (void __user *)address, tsk); |
d0542c7e VG |
197 | return; |
198 | ||
199 | no_context: | |
200 | if (fixup_exception(regs)) | |
201 | return; | |
202 | ||
203 | die("Oops", regs, address); | |
fbd7053a | 204 | } |