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08dbd0f8 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
499236d9 RK |
2 | /* |
3 | * Memory fault handling for Hexagon | |
4 | * | |
e1858b2a | 5 | * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved. |
499236d9 RK |
6 | */ |
7 | ||
8 | /* | |
9 | * Page fault handling for the Hexagon Virtual Machine. | |
10 | * Can also be called by a native port emulating the HVM | |
11 | * execptions. | |
12 | */ | |
13 | ||
499236d9 | 14 | #include <asm/traps.h> |
8126fafe | 15 | #include <asm/vm_fault.h> |
7c0f6ba6 | 16 | #include <linux/uaccess.h> |
499236d9 | 17 | #include <linux/mm.h> |
3f07c014 | 18 | #include <linux/sched/signal.h> |
499236d9 | 19 | #include <linux/signal.h> |
1e8fb9c3 | 20 | #include <linux/extable.h> |
499236d9 | 21 | #include <linux/hardirq.h> |
e08157c3 | 22 | #include <linux/perf_event.h> |
499236d9 RK |
23 | |
24 | /* | |
25 | * Decode of hardware exception sends us to one of several | |
26 | * entry points. At each, we generate canonical arguments | |
27 | * for handling by the abstract memory management code. | |
28 | */ | |
29 | #define FLT_IFETCH -1 | |
30 | #define FLT_LOAD 0 | |
31 | #define FLT_STORE 1 | |
32 | ||
33 | ||
34 | /* | |
35 | * Canonical page fault handler | |
36 | */ | |
d9d106ce | 37 | static void do_page_fault(unsigned long address, long cause, struct pt_regs *regs) |
499236d9 RK |
38 | { |
39 | struct vm_area_struct *vma; | |
40 | struct mm_struct *mm = current->mm; | |
1a4bd979 | 41 | int si_signo; |
499236d9 | 42 | int si_code = SEGV_MAPERR; |
50a7ca3c | 43 | vm_fault_t fault; |
499236d9 | 44 | const struct exception_table_entry *fixup; |
dde16072 | 45 | unsigned int flags = FAULT_FLAG_DEFAULT; |
499236d9 RK |
46 | |
47 | /* | |
48 | * If we're in an interrupt or have no user context, | |
49 | * then must not take the fault. | |
50 | */ | |
51 | if (unlikely(in_interrupt() || !mm)) | |
52 | goto no_context; | |
53 | ||
54 | local_irq_enable(); | |
55 | ||
759496ba JW |
56 | if (user_mode(regs)) |
57 | flags |= FAULT_FLAG_USER; | |
e08157c3 PX |
58 | |
59 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); | |
393a86af | 60 | retry: |
a050ba1e LT |
61 | vma = lock_mm_and_find_vma(mm, address, regs); |
62 | if (unlikely(!vma)) | |
63 | goto bad_area_nosemaphore; | |
499236d9 | 64 | |
499236d9 RK |
65 | /* Address space is OK. Now check access rights. */ |
66 | si_code = SEGV_ACCERR; | |
67 | ||
68 | switch (cause) { | |
69 | case FLT_IFETCH: | |
70 | if (!(vma->vm_flags & VM_EXEC)) | |
71 | goto bad_area; | |
72 | break; | |
73 | case FLT_LOAD: | |
74 | if (!(vma->vm_flags & VM_READ)) | |
75 | goto bad_area; | |
76 | break; | |
77 | case FLT_STORE: | |
78 | if (!(vma->vm_flags & VM_WRITE)) | |
79 | goto bad_area; | |
759496ba | 80 | flags |= FAULT_FLAG_WRITE; |
499236d9 RK |
81 | break; |
82 | } | |
83 | ||
e08157c3 | 84 | fault = handle_mm_fault(vma, address, flags, regs); |
393a86af | 85 | |
0b92ed09 AV |
86 | if (fault_signal_pending(fault, regs)) { |
87 | if (!user_mode(regs)) | |
88 | goto no_context; | |
393a86af | 89 | return; |
0b92ed09 | 90 | } |
499236d9 | 91 | |
d9272525 PX |
92 | /* The fault is fully completed (including releasing mmap lock) */ |
93 | if (fault & VM_FAULT_COMPLETED) | |
94 | return; | |
95 | ||
499236d9 RK |
96 | /* The most common case -- we are done. */ |
97 | if (likely(!(fault & VM_FAULT_ERROR))) { | |
36ef159f QZ |
98 | if (fault & VM_FAULT_RETRY) { |
99 | flags |= FAULT_FLAG_TRIED; | |
100 | goto retry; | |
393a86af | 101 | } |
499236d9 | 102 | |
d8ed45c5 | 103 | mmap_read_unlock(mm); |
499236d9 RK |
104 | return; |
105 | } | |
106 | ||
d8ed45c5 | 107 | mmap_read_unlock(mm); |
499236d9 RK |
108 | |
109 | /* Handle copyin/out exception cases */ | |
110 | if (!user_mode(regs)) | |
111 | goto no_context; | |
112 | ||
113 | if (fault & VM_FAULT_OOM) { | |
114 | pagefault_out_of_memory(); | |
115 | return; | |
116 | } | |
117 | ||
118 | /* User-mode address is in the memory map, but we are | |
119 | * unable to fix up the page fault. | |
120 | */ | |
121 | if (fault & VM_FAULT_SIGBUS) { | |
1a4bd979 EB |
122 | si_signo = SIGBUS; |
123 | si_code = BUS_ADRERR; | |
499236d9 RK |
124 | } |
125 | /* Address is not in the memory map */ | |
126 | else { | |
1a4bd979 EB |
127 | si_signo = SIGSEGV; |
128 | si_code = SEGV_ACCERR; | |
499236d9 | 129 | } |
2e1661d2 | 130 | force_sig_fault(si_signo, si_code, (void __user *)address); |
499236d9 RK |
131 | return; |
132 | ||
133 | bad_area: | |
d8ed45c5 | 134 | mmap_read_unlock(mm); |
499236d9 | 135 | |
a050ba1e | 136 | bad_area_nosemaphore: |
499236d9 | 137 | if (user_mode(regs)) { |
2e1661d2 | 138 | force_sig_fault(SIGSEGV, si_code, (void __user *)address); |
499236d9 RK |
139 | return; |
140 | } | |
141 | /* Kernel-mode fault falls through */ | |
142 | ||
143 | no_context: | |
144 | fixup = search_exception_tables(pt_elr(regs)); | |
145 | if (fixup) { | |
146 | pt_set_elr(regs, fixup->fixup); | |
147 | return; | |
148 | } | |
149 | ||
150 | /* Things are looking very, very bad now */ | |
151 | bust_spinlocks(1); | |
152 | printk(KERN_EMERG "Unable to handle kernel paging request at " | |
153 | "virtual address 0x%08lx, regs %p\n", address, regs); | |
154 | die("Bad Kernel VA", regs, SIGKILL); | |
155 | } | |
156 | ||
157 | ||
158 | void read_protection_fault(struct pt_regs *regs) | |
159 | { | |
160 | unsigned long badvadr = pt_badva(regs); | |
161 | ||
162 | do_page_fault(badvadr, FLT_LOAD, regs); | |
163 | } | |
164 | ||
165 | void write_protection_fault(struct pt_regs *regs) | |
166 | { | |
167 | unsigned long badvadr = pt_badva(regs); | |
168 | ||
169 | do_page_fault(badvadr, FLT_STORE, regs); | |
170 | } | |
171 | ||
172 | void execute_protection_fault(struct pt_regs *regs) | |
173 | { | |
174 | unsigned long badvadr = pt_badva(regs); | |
175 | ||
176 | do_page_fault(badvadr, FLT_IFETCH, regs); | |
177 | } |