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181 lines
3.7 KiB
181 lines
3.7 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Memory fault handling for Hexagon |
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* |
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* Copyright (c) 2010-2011, The Linux Foundation. All rights reserved. |
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*/ |
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/* |
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* Page fault handling for the Hexagon Virtual Machine. |
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* Can also be called by a native port emulating the HVM |
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* execptions. |
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*/ |
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#include <asm/traps.h> |
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#include <linux/uaccess.h> |
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#include <linux/mm.h> |
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#include <linux/sched/signal.h> |
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#include <linux/signal.h> |
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#include <linux/extable.h> |
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#include <linux/hardirq.h> |
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#include <linux/perf_event.h> |
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/* |
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* Decode of hardware exception sends us to one of several |
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* entry points. At each, we generate canonical arguments |
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* for handling by the abstract memory management code. |
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*/ |
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#define FLT_IFETCH -1 |
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#define FLT_LOAD 0 |
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#define FLT_STORE 1 |
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/* |
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* Canonical page fault handler |
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*/ |
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void do_page_fault(unsigned long address, long cause, struct pt_regs *regs) |
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{ |
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struct vm_area_struct *vma; |
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struct mm_struct *mm = current->mm; |
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int si_signo; |
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int si_code = SEGV_MAPERR; |
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vm_fault_t fault; |
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const struct exception_table_entry *fixup; |
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unsigned int flags = FAULT_FLAG_DEFAULT; |
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/* |
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* If we're in an interrupt or have no user context, |
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* then must not take the fault. |
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*/ |
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if (unlikely(in_interrupt() || !mm)) |
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goto no_context; |
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local_irq_enable(); |
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if (user_mode(regs)) |
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flags |= FAULT_FLAG_USER; |
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perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); |
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retry: |
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mmap_read_lock(mm); |
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vma = find_vma(mm, address); |
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if (!vma) |
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goto bad_area; |
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if (vma->vm_start <= address) |
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goto good_area; |
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if (!(vma->vm_flags & VM_GROWSDOWN)) |
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goto bad_area; |
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if (expand_stack(vma, address)) |
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goto bad_area; |
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good_area: |
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/* Address space is OK. Now check access rights. */ |
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si_code = SEGV_ACCERR; |
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switch (cause) { |
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case FLT_IFETCH: |
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if (!(vma->vm_flags & VM_EXEC)) |
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goto bad_area; |
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break; |
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case FLT_LOAD: |
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if (!(vma->vm_flags & VM_READ)) |
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goto bad_area; |
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break; |
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case FLT_STORE: |
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if (!(vma->vm_flags & VM_WRITE)) |
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goto bad_area; |
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flags |= FAULT_FLAG_WRITE; |
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break; |
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} |
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fault = handle_mm_fault(vma, address, flags, regs); |
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if (fault_signal_pending(fault, regs)) |
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return; |
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/* The most common case -- we are done. */ |
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if (likely(!(fault & VM_FAULT_ERROR))) { |
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if (flags & FAULT_FLAG_ALLOW_RETRY) { |
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if (fault & VM_FAULT_RETRY) { |
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flags |= FAULT_FLAG_TRIED; |
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goto retry; |
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} |
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} |
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mmap_read_unlock(mm); |
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return; |
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} |
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mmap_read_unlock(mm); |
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/* Handle copyin/out exception cases */ |
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if (!user_mode(regs)) |
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goto no_context; |
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if (fault & VM_FAULT_OOM) { |
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pagefault_out_of_memory(); |
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return; |
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} |
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/* User-mode address is in the memory map, but we are |
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* unable to fix up the page fault. |
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*/ |
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if (fault & VM_FAULT_SIGBUS) { |
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si_signo = SIGBUS; |
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si_code = BUS_ADRERR; |
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} |
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/* Address is not in the memory map */ |
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else { |
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si_signo = SIGSEGV; |
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si_code = SEGV_ACCERR; |
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} |
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force_sig_fault(si_signo, si_code, (void __user *)address); |
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return; |
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bad_area: |
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mmap_read_unlock(mm); |
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if (user_mode(regs)) { |
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force_sig_fault(SIGSEGV, si_code, (void __user *)address); |
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return; |
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} |
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/* Kernel-mode fault falls through */ |
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no_context: |
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fixup = search_exception_tables(pt_elr(regs)); |
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if (fixup) { |
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pt_set_elr(regs, fixup->fixup); |
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return; |
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} |
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/* Things are looking very, very bad now */ |
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bust_spinlocks(1); |
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printk(KERN_EMERG "Unable to handle kernel paging request at " |
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"virtual address 0x%08lx, regs %p\n", address, regs); |
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die("Bad Kernel VA", regs, SIGKILL); |
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} |
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void read_protection_fault(struct pt_regs *regs) |
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{ |
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unsigned long badvadr = pt_badva(regs); |
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do_page_fault(badvadr, FLT_LOAD, regs); |
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} |
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void write_protection_fault(struct pt_regs *regs) |
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{ |
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unsigned long badvadr = pt_badva(regs); |
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do_page_fault(badvadr, FLT_STORE, regs); |
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} |
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void execute_protection_fault(struct pt_regs *regs) |
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{ |
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unsigned long badvadr = pt_badva(regs); |
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do_page_fault(badvadr, FLT_IFETCH, regs); |
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}
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