6  *  Derived from "arch/i386/mm/fault.c"
106 	 * 5. T1   : enters fault handler, takes mmap_lock, etc...  in bad_access_pkey()
133 		     vm_fault_t fault)  in do_sigbus()  argument
140 	if (fault & (VM_FAULT_HWPOISON|VM_FAULT_HWPOISON_LARGE)) {  in do_sigbus()
143 		pr_err("MCE: Killing %s:%d due to hardware memory corruption fault at %lx\n",  in do_sigbus()
146 		if (fault & VM_FAULT_HWPOISON_LARGE)  in do_sigbus()
147 			lsb = hstate_index_to_shift(VM_FAULT_GET_HINDEX(fault));  in do_sigbus()
148 		if (fault & VM_FAULT_HWPOISON)  in do_sigbus()
161 				vm_fault_t fault)  in mm_fault_error()  argument
164 	 * Kernel page fault interrupted by SIGKILL. We have no reason to  in mm_fault_error()
171 	if (fault & VM_FAULT_OOM) {  in mm_fault_error()
174 		 * made us unable to handle the page fault gracefully.  in mm_fault_error()
180 		if (fault & (VM_FAULT_SIGBUS|VM_FAULT_HWPOISON|  in mm_fault_error()
182 			return do_sigbus(regs, addr, fault);  in mm_fault_error()
183 		else if (fault & VM_FAULT_SIGSEGV)  in mm_fault_error()
191 /* Is this a bad kernel fault ? */
203 		// Kernel exec fault is always bad  in bad_kernel_fault()
207 	// Kernel fault on kernel address is bad  in bad_kernel_fault()
211 	// Read/write fault blocked by KUAP is bad, it can never succeed.  in bad_kernel_fault()
217 		// Fault on user outside of certain regions (eg. copy_tofrom_user()) is bad  in bad_kernel_fault()
221 		// Read/write fault in a valid region (the exception table search passed  in bad_kernel_fault()
223 		return WARN(true, "Bug: %s fault blocked by KUAP!", is_write ? "Write" : "Read");  in bad_kernel_fault()
226 	// What's left? Kernel fault on user and allowed by KUAP in the faulting context.  in bad_kernel_fault()
235 	 * faults just to hit a pkey fault as soon as we fill in a  in access_pkey_error()
281 	 * fault path, handle_mm_fault() also does the same check. To avoid  in access_error()
328 	 * fault instead of DSISR_PROTFAULT.  in sanity_check_fault()
337 	 * sync between D/I cache via fault. But that is handled via low level  in sanity_check_fault()
338 	 * hash fault code (hash_page_do_lazy_icache()) and we should not reach  in sanity_check_fault()
347 	 * set_pte_at while taking the noexec/prot fault. Hence this is WARN_ON  in sanity_check_fault()
350 	 * For radix, we can get prot fault for autonuma case, because radix  in sanity_check_fault()
396  * for a data fault, SRR1 for an instruction fault.
397  * For 400-family processors the error_code parameter is ESR for a data fault,
398  * 0 for an instruction fault.
400  * fault, SRR1 & 0x08000000 for an instruction access fault.
402  * The return value is 0 if the fault was handled, or the signal
403  * number if this is a kernel fault that can't be handled here.
414 	vm_fault_t fault, major = 0;  in ___do_page_fault()  local
432 	 * The kernel should never take an execute fault nor should it  in ___do_page_fault()
433 	 * take a page fault to a kernel address or a page fault to a user  in ___do_page_fault()
437 	 * the NIP belongs to the fixup table for cases where fault could come  in ___do_page_fault()
451 	 * in a region with pagefaults disabled then we must not take the fault  in ___do_page_fault()
455 			printk_ratelimited(KERN_ERR "Page fault in user mode"  in ___do_page_fault()
468 	 * can result in fault, which will cause a deadlock when called with  in ___do_page_fault()
496 	fault = handle_mm_fault(vma, address, flags | FAULT_FLAG_VMA_LOCK, regs);  in ___do_page_fault()
497 	if (!(fault & (VM_FAULT_RETRY | VM_FAULT_COMPLETED)))  in ___do_page_fault()
500 	if (!(fault & VM_FAULT_RETRY)) {  in ___do_page_fault()
506 	if (fault_signal_pending(fault, regs))  in ___do_page_fault()
514 	 * erroneous fault occurring in a code path which already holds mmap_lock  in ___do_page_fault()
515 	 * we will deadlock attempting to validate the fault against the  in ___do_page_fault()
533 	 * If for any reason at all we couldn't handle the fault,  in ___do_page_fault()
535 	 * the fault.  in ___do_page_fault()
537 	fault = handle_mm_fault(vma, address, flags, regs);  in ___do_page_fault()
539 	major |= fault & VM_FAULT_MAJOR;  in ___do_page_fault()
541 	if (fault_signal_pending(fault, regs))  in ___do_page_fault()
544 	/* The fault is fully completed (including releasing mmap lock) */  in ___do_page_fault()
545 	if (fault & VM_FAULT_COMPLETED)  in ___do_page_fault()
552 	if (unlikely(fault & VM_FAULT_RETRY)) {  in ___do_page_fault()
560 	if (unlikely(fault & VM_FAULT_ERROR))  in ___do_page_fault()
561 		return mm_fault_error(regs, address, fault);  in ___do_page_fault()
565 	 * Major/minor page fault accounting.  in ___do_page_fault()
633 		pr_alert("BUG: Unable to handle unknown paging fault at 0x%08lx\n",  in __bad_page_fault()
650 	/* Are we prepared to handle this fault?  */  in bad_page_fault()