page fault

Linux v6.6: arch/arm64/mm/fault.c
Linux v6.6: mm/memory.c
Linux v6.6: mm/mmap.c

}

#define VM_FAULT_BADMAP		((__force vm_fault_t)0x010000)
#define VM_FAULT_BADACCESS	((__force vm_fault_t)0x020000)

static vm_fault_t __do_page_fault(struct mm_struct *mm,
				  struct vm_area_struct *vma, unsigned long addr,
				  unsigned int mm_flags, unsigned long vm_flags,
				  struct pt_regs *regs)
{
	/*
	 * Ok, we have a good vm_area for this memory access, so we can handle
	 * it.
	 * Check that the permissions on the VMA allow for the fault which
	 * occurred.
	 */
	if (!(vma->vm_flags & vm_flags))
		return VM_FAULT_BADACCESS;
	return handle_mm_fault(vma, addr, mm_flags, regs);
}

static bool is_el0_instruction_abort(unsigned long esr)
{
	return ESR_ELx_EC(esr) == ESR_ELx_EC_IABT_LOW;
}

/*
 * Note: not valid for EL1 DC IVAC, but we never use that such that it
 * should fault. EL0 cannot issue DC IVAC (undef).
 */
static bool is_write_abort(unsigned long esr)
{
	return (esr & ESR_ELx_WNR) && !(esr & ESR_ELx_CM);
}

static int __kprobes do_page_fault(unsigned long far, unsigned long esr,
				   struct pt_regs *regs)
{
	const struct fault_info *inf;
	struct mm_struct *mm = current->mm;

	 * Check that the permissions on the VMA allow for the fault which
	 * occurred.
	 */
	if (!(vma->vm_flags & vm_flags))
		return VM_FAULT_BADACCESS;
	return handle_mm_fault(vma, addr, mm_flags, regs);
}

static bool is_el0_instruction_abort(unsigned long esr)
{
	return ESR_ELx_EC(esr) == ESR_ELx_EC_IABT_LOW;
}

/*
 * Note: not valid for EL1 DC IVAC, but we never use that such that it
 * should fault. EL0 cannot issue DC IVAC (undef).
 */
static bool is_write_abort(unsigned long esr)
{
	return (esr & ESR_ELx_WNR) && !(esr & ESR_ELx_CM);
}

static int __kprobes do_page_fault(unsigned long far, unsigned long esr,
				   struct pt_regs *regs)
{
	const struct fault_info *inf;
	struct mm_struct *mm = current->mm;
	vm_fault_t fault;
	unsigned long vm_flags;
	unsigned int mm_flags = FAULT_FLAG_DEFAULT;
	unsigned long addr = untagged_addr(far);
	struct vm_area_struct *vma;

	if (kprobe_page_fault(regs, esr))
		return 0;

	/*
	 * If we're in an interrupt or have no user context, we must not take
	 * the fault.
	 */