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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; | |
6aae3425 | 33 | p4d_t *p4d, *p4d_k; |
fbd7053a VG |
34 | pud_t *pud, *pud_k; |
35 | pmd_t *pmd, *pmd_k; | |
36 | ||
9c41f4ee | 37 | pgd = pgd_offset_fast(current->active_mm, address); |
fbd7053a VG |
38 | pgd_k = pgd_offset_k(address); |
39 | ||
40 | if (!pgd_present(*pgd_k)) | |
41 | goto bad_area; | |
42 | ||
6aae3425 VG |
43 | p4d = p4d_offset(pgd, address); |
44 | p4d_k = p4d_offset(pgd_k, address); | |
45 | if (!p4d_present(*p4d_k)) | |
46 | goto bad_area; | |
47 | ||
48 | pud = pud_offset(p4d, address); | |
49 | pud_k = pud_offset(p4d_k, address); | |
fbd7053a VG |
50 | if (!pud_present(*pud_k)) |
51 | goto bad_area; | |
52 | ||
53 | pmd = pmd_offset(pud, address); | |
54 | pmd_k = pmd_offset(pud_k, address); | |
55 | if (!pmd_present(*pmd_k)) | |
56 | goto bad_area; | |
57 | ||
58 | set_pmd(pmd, *pmd_k); | |
59 | ||
60 | /* XXX: create the TLB entry here */ | |
61 | return 0; | |
62 | ||
63 | bad_area: | |
64 | return 1; | |
65 | } | |
66 | ||
21a63b56 | 67 | void do_page_fault(unsigned long address, struct pt_regs *regs) |
fbd7053a VG |
68 | { |
69 | struct vm_area_struct *vma = NULL; | |
70 | struct task_struct *tsk = current; | |
71 | struct mm_struct *mm = tsk->mm; | |
5e91bf5c | 72 | int sig, si_code = SEGV_MAPERR; |
85c5e337 | 73 | unsigned int write = 0, exec = 0, mask; |
5e91bf5c | 74 | vm_fault_t fault = VM_FAULT_SIGSEGV; /* handle_mm_fault() output */ |
02c88d14 | 75 | unsigned int flags; /* handle_mm_fault() input */ |
fbd7053a VG |
76 | |
77 | /* | |
fbd7053a VG |
78 | * NOTE! We MUST NOT take any locks for this case. We may |
79 | * be in an interrupt or a critical region, and should | |
80 | * only copy the information from the master page table, | |
81 | * nothing more. | |
82 | */ | |
a8c715b4 | 83 | if (address >= VMALLOC_START && !user_mode(regs)) { |
13e2cc12 | 84 | if (unlikely(handle_kernel_vaddr_fault(address))) |
a8c715b4 | 85 | goto no_context; |
fbd7053a VG |
86 | else |
87 | return; | |
88 | } | |
89 | ||
fbd7053a VG |
90 | /* |
91 | * If we're in an interrupt or have no user | |
92 | * context, we must not take the fault.. | |
93 | */ | |
70ffdb93 | 94 | if (faulthandler_disabled() || !mm) |
fbd7053a VG |
95 | goto no_context; |
96 | ||
85c5e337 VG |
97 | if (regs->ecr_cause & ECR_C_PROTV_STORE) /* ST/EX */ |
98 | write = 1; | |
99 | else if ((regs->ecr_vec == ECR_V_PROTV) && | |
100 | (regs->ecr_cause == ECR_C_PROTV_INST_FETCH)) | |
101 | exec = 1; | |
102 | ||
dde16072 | 103 | flags = FAULT_FLAG_DEFAULT; |
759496ba JW |
104 | if (user_mode(regs)) |
105 | flags |= FAULT_FLAG_USER; | |
85c5e337 VG |
106 | if (write) |
107 | flags |= FAULT_FLAG_WRITE; | |
108 | ||
fbd7053a | 109 | retry: |
d8ed45c5 | 110 | mmap_read_lock(mm); |
450e5b6f | 111 | |
fbd7053a VG |
112 | vma = find_vma(mm, address); |
113 | if (!vma) | |
114 | goto bad_area; | |
450e5b6f VG |
115 | if (unlikely(address < vma->vm_start)) { |
116 | if (!(vma->vm_flags & VM_GROWSDOWN) || expand_stack(vma, address)) | |
117 | goto bad_area; | |
118 | } | |
fbd7053a VG |
119 | |
120 | /* | |
85c5e337 | 121 | * vm_area is good, now check permissions for this memory access |
fbd7053a | 122 | */ |
85c5e337 VG |
123 | mask = VM_READ; |
124 | if (write) | |
125 | mask = VM_WRITE; | |
126 | if (exec) | |
127 | mask = VM_EXEC; | |
128 | ||
129 | if (!(vma->vm_flags & mask)) { | |
130 | si_code = SEGV_ACCERR; | |
fbd7053a | 131 | goto bad_area; |
fbd7053a VG |
132 | } |
133 | ||
dcddffd4 | 134 | fault = handle_mm_fault(vma, address, flags); |
fbd7053a | 135 | |
24a62cf4 PX |
136 | /* Quick path to respond to signals */ |
137 | if (fault_signal_pending(fault, regs)) { | |
138 | if (!user_mode(regs)) | |
139 | goto no_context; | |
140 | return; | |
141 | } | |
142 | ||
02c88d14 | 143 | /* |
c1e8d7c6 | 144 | * Fault retry nuances, mmap_lock already relinquished by core mm |
02c88d14 | 145 | */ |
24a62cf4 PX |
146 | if (unlikely((fault & VM_FAULT_RETRY) && |
147 | (flags & FAULT_FLAG_ALLOW_RETRY))) { | |
24a62cf4 PX |
148 | flags |= FAULT_FLAG_TRIED; |
149 | goto retry; | |
fbd7053a VG |
150 | } |
151 | ||
926150db | 152 | bad_area: |
d8ed45c5 | 153 | mmap_read_unlock(mm); |
fbd7053a VG |
154 | |
155 | /* | |
02c88d14 VG |
156 | * Major/minor page fault accounting |
157 | * (in case of retry we only land here once) | |
fbd7053a | 158 | */ |
ceed97ab | 159 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); |
fbd7053a | 160 | |
fbd7053a | 161 | if (likely(!(fault & VM_FAULT_ERROR))) { |
02c88d14 VG |
162 | if (fault & VM_FAULT_MAJOR) { |
163 | tsk->maj_flt++; | |
164 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, | |
165 | regs, address); | |
166 | } else { | |
167 | tsk->min_flt++; | |
168 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, | |
169 | regs, address); | |
fbd7053a | 170 | } |
fbd7053a | 171 | |
02c88d14 | 172 | /* Normal return path: fault Handled Gracefully */ |
fbd7053a | 173 | return; |
fbd7053a | 174 | } |
fbd7053a | 175 | |
98cb57ad VG |
176 | if (!user_mode(regs)) |
177 | goto no_context; | |
fbd7053a | 178 | |
5e91bf5c | 179 | if (fault & VM_FAULT_OOM) { |
609838cf JW |
180 | pagefault_out_of_memory(); |
181 | return; | |
182 | } | |
fbd7053a | 183 | |
5e91bf5c VG |
184 | if (fault & VM_FAULT_SIGBUS) { |
185 | sig = SIGBUS; | |
186 | si_code = BUS_ADRERR; | |
187 | } | |
188 | else { | |
189 | sig = SIGSEGV; | |
190 | } | |
fbd7053a | 191 | |
fbd7053a | 192 | tsk->thread.fault_address = address; |
3eb51486 | 193 | force_sig_fault(sig, si_code, (void __user *)address); |
d0542c7e | 194 | return; |
fbd7053a | 195 | |
d0542c7e VG |
196 | no_context: |
197 | if (fixup_exception(regs)) | |
198 | return; | |
fbd7053a | 199 | |
d0542c7e | 200 | die("Oops", regs, address); |
fbd7053a | 201 | } |