1 // SPDX-License-Identifier: GPL-2.0-only
3 * Memory fault handling for Hexagon
5 * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
9 * Page fault handling for the Hexagon Virtual Machine.
10 * Can also be called by a native port emulating the HVM
14 #include <asm/traps.h>
15 #include <linux/uaccess.h>
17 #include <linux/sched/signal.h>
18 #include <linux/signal.h>
19 #include <linux/extable.h>
20 #include <linux/hardirq.h>
21 #include <linux/perf_event.h>
24 * Decode of hardware exception sends us to one of several
25 * entry points. At each, we generate canonical arguments
26 * for handling by the abstract memory management code.
34 * Canonical page fault handler
36 void do_page_fault(unsigned long address, long cause, struct pt_regs *regs)
38 struct vm_area_struct *vma;
39 struct mm_struct *mm = current->mm;
41 int si_code = SEGV_MAPERR;
43 const struct exception_table_entry *fixup;
44 unsigned int flags = FAULT_FLAG_DEFAULT;
47 * If we're in an interrupt or have no user context,
48 * then must not take the fault.
50 if (unlikely(in_interrupt() || !mm))
56 flags |= FAULT_FLAG_USER;
58 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
60 vma = lock_mm_and_find_vma(mm, address, regs);
62 goto bad_area_nosemaphore;
64 /* Address space is OK. Now check access rights. */
65 si_code = SEGV_ACCERR;
69 if (!(vma->vm_flags & VM_EXEC))
73 if (!(vma->vm_flags & VM_READ))
77 if (!(vma->vm_flags & VM_WRITE))
79 flags |= FAULT_FLAG_WRITE;
83 fault = handle_mm_fault(vma, address, flags, regs);
85 if (fault_signal_pending(fault, regs))
88 /* The fault is fully completed (including releasing mmap lock) */
89 if (fault & VM_FAULT_COMPLETED)
92 /* The most common case -- we are done. */
93 if (likely(!(fault & VM_FAULT_ERROR))) {
94 if (fault & VM_FAULT_RETRY) {
95 flags |= FAULT_FLAG_TRIED;
103 mmap_read_unlock(mm);
105 /* Handle copyin/out exception cases */
106 if (!user_mode(regs))
109 if (fault & VM_FAULT_OOM) {
110 pagefault_out_of_memory();
114 /* User-mode address is in the memory map, but we are
115 * unable to fix up the page fault.
117 if (fault & VM_FAULT_SIGBUS) {
119 si_code = BUS_ADRERR;
121 /* Address is not in the memory map */
124 si_code = SEGV_ACCERR;
126 force_sig_fault(si_signo, si_code, (void __user *)address);
130 mmap_read_unlock(mm);
132 bad_area_nosemaphore:
133 if (user_mode(regs)) {
134 force_sig_fault(SIGSEGV, si_code, (void __user *)address);
137 /* Kernel-mode fault falls through */
140 fixup = search_exception_tables(pt_elr(regs));
142 pt_set_elr(regs, fixup->fixup);
146 /* Things are looking very, very bad now */
148 printk(KERN_EMERG "Unable to handle kernel paging request at "
149 "virtual address 0x%08lx, regs %p\n", address, regs);
150 die("Bad Kernel VA", regs, SIGKILL);
154 void read_protection_fault(struct pt_regs *regs)
156 unsigned long badvadr = pt_badva(regs);
158 do_page_fault(badvadr, FLT_LOAD, regs);
161 void write_protection_fault(struct pt_regs *regs)
163 unsigned long badvadr = pt_badva(regs);
165 do_page_fault(badvadr, FLT_STORE, regs);
168 void execute_protection_fault(struct pt_regs *regs)
170 unsigned long badvadr = pt_badva(regs);
172 do_page_fault(badvadr, FLT_IFETCH, regs);