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1// SPDX-License-Identifier: GPL-2.0-only
2/* Page Fault Handling for ARC (TLB Miss / ProtV)
3 *
4 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
5 */
6
7#include <linux/signal.h>
8#include <linux/interrupt.h>
9#include <linux/sched/signal.h>
10#include <linux/errno.h>
11#include <linux/ptrace.h>
12#include <linux/uaccess.h>
13#include <linux/kdebug.h>
14#include <linux/perf_event.h>
15#include <linux/mm_types.h>
16#include <asm/mmu.h>
17
18/*
19 * kernel virtual address is required to implement vmalloc/pkmap/fixmap
20 * Refer to asm/processor.h for System Memory Map
21 *
22 * It simply copies the PMD entry (pointer to 2nd level page table or hugepage)
23 * from swapper pgdir to task pgdir. The 2nd level table/page is thus shared
24 */
25noinline static int handle_kernel_vaddr_fault(unsigned long address)
26{
27 /*
28 * Synchronize this task's top level page-table
29 * with the 'reference' page table.
30 */
31 pgd_t *pgd, *pgd_k;
32 p4d_t *p4d, *p4d_k;
33 pud_t *pud, *pud_k;
34 pmd_t *pmd, *pmd_k;
35
36 pgd = pgd_offset_fast(current->active_mm, address);
37 pgd_k = pgd_offset_k(address);
38
39 if (!pgd_present(*pgd_k))
40 goto bad_area;
41
42 p4d = p4d_offset(pgd, address);
43 p4d_k = p4d_offset(pgd_k, address);
44 if (!p4d_present(*p4d_k))
45 goto bad_area;
46
47 pud = pud_offset(p4d, address);
48 pud_k = pud_offset(p4d_k, address);
49 if (!pud_present(*pud_k))
50 goto bad_area;
51
52 pmd = pmd_offset(pud, address);
53 pmd_k = pmd_offset(pud_k, address);
54 if (!pmd_present(*pmd_k))
55 goto bad_area;
56
57 set_pmd(pmd, *pmd_k);
58
59 /* XXX: create the TLB entry here */
60 return 0;
61
62bad_area:
63 return 1;
64}
65
66void do_page_fault(unsigned long address, struct pt_regs *regs)
67{
68 struct vm_area_struct *vma = NULL;
69 struct task_struct *tsk = current;
70 struct mm_struct *mm = tsk->mm;
71 int sig, si_code = SEGV_MAPERR;
72 unsigned int write = 0, exec = 0, mask;
73 vm_fault_t fault = VM_FAULT_SIGSEGV; /* handle_mm_fault() output */
74 unsigned int flags; /* handle_mm_fault() input */
75
76 /*
77 * NOTE! We MUST NOT take any locks for this case. We may
78 * be in an interrupt or a critical region, and should
79 * only copy the information from the master page table,
80 * nothing more.
81 */
82 if (address >= VMALLOC_START && !user_mode(regs)) {
83 if (unlikely(handle_kernel_vaddr_fault(address)))
84 goto no_context;
85 else
86 return;
87 }
88
89 /*
90 * If we're in an interrupt or have no user
91 * context, we must not take the fault..
92 */
93 if (faulthandler_disabled() || !mm)
94 goto no_context;
95
96 if (regs->ecr_cause & ECR_C_PROTV_STORE) /* ST/EX */
97 write = 1;
98 else if ((regs->ecr_vec == ECR_V_PROTV) &&
99 (regs->ecr_cause == ECR_C_PROTV_INST_FETCH))
100 exec = 1;
101
102 flags = FAULT_FLAG_DEFAULT;
103 if (user_mode(regs))
104 flags |= FAULT_FLAG_USER;
105 if (write)
106 flags |= FAULT_FLAG_WRITE;
107
108 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
109retry:
110 mmap_read_lock(mm);
111
112 vma = find_vma(mm, address);
113 if (!vma)
114 goto bad_area;
115 if (unlikely(address < vma->vm_start)) {
116 if (!(vma->vm_flags & VM_GROWSDOWN) || expand_stack(vma, address))
117 goto bad_area;
118 }
119
120 /*
121 * vm_area is good, now check permissions for this memory access
122 */
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;
131 goto bad_area;
132 }
133
134 fault = handle_mm_fault(vma, address, flags, regs);
135
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
143 /*
144 * Fault retry nuances, mmap_lock already relinquished by core mm
145 */
146 if (unlikely((fault & VM_FAULT_RETRY) &&
147 (flags & FAULT_FLAG_ALLOW_RETRY))) {
148 flags |= FAULT_FLAG_TRIED;
149 goto retry;
150 }
151
152bad_area:
153 mmap_read_unlock(mm);
154
155 /*
156 * Major/minor page fault accounting
157 * (in case of retry we only land here once)
158 */
159 if (likely(!(fault & VM_FAULT_ERROR)))
160 /* Normal return path: fault Handled Gracefully */
161 return;
162
163 if (!user_mode(regs))
164 goto no_context;
165
166 if (fault & VM_FAULT_OOM) {
167 pagefault_out_of_memory();
168 return;
169 }
170
171 if (fault & VM_FAULT_SIGBUS) {
172 sig = SIGBUS;
173 si_code = BUS_ADRERR;
174 }
175 else {
176 sig = SIGSEGV;
177 }
178
179 tsk->thread.fault_address = address;
180 force_sig_fault(sig, si_code, (void __user *)address);
181 return;
182
183no_context:
184 if (fixup_exception(regs))
185 return;
186
187 die("Oops", regs, address);
188}
1// SPDX-License-Identifier: GPL-2.0-only
2/* Page Fault Handling for ARC (TLB Miss / ProtV)
3 *
4 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
5 */
6
7#include <linux/signal.h>
8#include <linux/interrupt.h>
9#include <linux/sched/signal.h>
10#include <linux/errno.h>
11#include <linux/ptrace.h>
12#include <linux/uaccess.h>
13#include <linux/kdebug.h>
14#include <linux/perf_event.h>
15#include <linux/mm_types.h>
16#include <asm/entry.h>
17#include <asm/mmu.h>
18
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 */
26noinline static int handle_kernel_vaddr_fault(unsigned long address)
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 p4d_t *p4d, *p4d_k;
34 pud_t *pud, *pud_k;
35 pmd_t *pmd, *pmd_k;
36
37 pgd = pgd_offset(current->active_mm, address);
38 pgd_k = pgd_offset_k(address);
39
40 if (pgd_none (*pgd_k))
41 goto bad_area;
42 if (!pgd_present(*pgd))
43 set_pgd(pgd, *pgd_k);
44
45 p4d = p4d_offset(pgd, address);
46 p4d_k = p4d_offset(pgd_k, address);
47 if (p4d_none(*p4d_k))
48 goto bad_area;
49 if (!p4d_present(*p4d))
50 set_p4d(p4d, *p4d_k);
51
52 pud = pud_offset(p4d, address);
53 pud_k = pud_offset(p4d_k, address);
54 if (pud_none(*pud_k))
55 goto bad_area;
56 if (!pud_present(*pud))
57 set_pud(pud, *pud_k);
58
59 pmd = pmd_offset(pud, address);
60 pmd_k = pmd_offset(pud_k, address);
61 if (pmd_none(*pmd_k))
62 goto bad_area;
63 if (!pmd_present(*pmd))
64 set_pmd(pmd, *pmd_k);
65
66 /* XXX: create the TLB entry here */
67 return 0;
68
69bad_area:
70 return 1;
71}
72
73void do_page_fault(unsigned long address, struct pt_regs *regs)
74{
75 struct vm_area_struct *vma = NULL;
76 struct task_struct *tsk = current;
77 struct mm_struct *mm = tsk->mm;
78 int sig, si_code = SEGV_MAPERR;
79 unsigned int write = 0, exec = 0, mask;
80 vm_fault_t fault = VM_FAULT_SIGSEGV; /* handle_mm_fault() output */
81 unsigned int flags; /* handle_mm_fault() input */
82
83 /*
84 * NOTE! We MUST NOT take any locks for this case. We may
85 * be in an interrupt or a critical region, and should
86 * only copy the information from the master page table,
87 * nothing more.
88 */
89 if (address >= VMALLOC_START && !user_mode(regs)) {
90 if (unlikely(handle_kernel_vaddr_fault(address)))
91 goto no_context;
92 else
93 return;
94 }
95
96 /*
97 * If we're in an interrupt or have no user
98 * context, we must not take the fault..
99 */
100 if (faulthandler_disabled() || !mm)
101 goto no_context;
102
103 if (regs->ecr.cause & ECR_C_PROTV_STORE) /* ST/EX */
104 write = 1;
105 else if ((regs->ecr.vec == ECR_V_PROTV) &&
106 (regs->ecr.cause == ECR_C_PROTV_INST_FETCH))
107 exec = 1;
108
109 flags = FAULT_FLAG_DEFAULT;
110 if (user_mode(regs))
111 flags |= FAULT_FLAG_USER;
112 if (write)
113 flags |= FAULT_FLAG_WRITE;
114
115 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
116retry:
117 vma = lock_mm_and_find_vma(mm, address, regs);
118 if (!vma)
119 goto bad_area_nosemaphore;
120
121 /*
122 * vm_area is good, now check permissions for this memory access
123 */
124 mask = VM_READ;
125 if (write)
126 mask = VM_WRITE;
127 if (exec)
128 mask = VM_EXEC;
129
130 if (!(vma->vm_flags & mask)) {
131 si_code = SEGV_ACCERR;
132 goto bad_area;
133 }
134
135 fault = handle_mm_fault(vma, address, flags, regs);
136
137 /* Quick path to respond to signals */
138 if (fault_signal_pending(fault, regs)) {
139 if (!user_mode(regs))
140 goto no_context;
141 return;
142 }
143
144 /* The fault is fully completed (including releasing mmap lock) */
145 if (fault & VM_FAULT_COMPLETED)
146 return;
147
148 /*
149 * Fault retry nuances, mmap_lock already relinquished by core mm
150 */
151 if (unlikely(fault & VM_FAULT_RETRY)) {
152 flags |= FAULT_FLAG_TRIED;
153 goto retry;
154 }
155
156bad_area:
157 mmap_read_unlock(mm);
158
159bad_area_nosemaphore:
160 /*
161 * Major/minor page fault accounting
162 * (in case of retry we only land here once)
163 */
164 if (likely(!(fault & VM_FAULT_ERROR)))
165 /* Normal return path: fault Handled Gracefully */
166 return;
167
168 if (!user_mode(regs))
169 goto no_context;
170
171 if (fault & VM_FAULT_OOM) {
172 pagefault_out_of_memory();
173 return;
174 }
175
176 if (fault & VM_FAULT_SIGBUS) {
177 sig = SIGBUS;
178 si_code = BUS_ADRERR;
179 }
180 else {
181 sig = SIGSEGV;
182 }
183
184 tsk->thread.fault_address = address;
185 force_sig_fault(sig, si_code, (void __user *)address);
186 return;
187
188no_context:
189 if (fixup_exception(regs))
190 return;
191
192 die("Oops", regs, address);
193}