6  *  Derived from "arch/i386/mm/fault.c"
109 	 * 5. T1   : enters fault handler, takes mmap_lock, etc...  in bad_access_pkey()
137 		     vm_fault_t fault)  in do_sigbus()  argument
144 	if (fault & (VM_FAULT_HWPOISON|VM_FAULT_HWPOISON_LARGE)) {  in do_sigbus()
147 		pr_err("MCE: Killing %s:%d due to hardware memory corruption fault at %lx\n",  in do_sigbus()
150 		if (fault & VM_FAULT_HWPOISON_LARGE)  in do_sigbus()
151 			lsb = hstate_index_to_shift(VM_FAULT_GET_HINDEX(fault));  in do_sigbus()
152 		if (fault & VM_FAULT_HWPOISON)  in do_sigbus()
165 				vm_fault_t fault)  in mm_fault_error()  argument
168 	 * Kernel page fault interrupted by SIGKILL. We have no reason to  in mm_fault_error()
175 	if (fault & VM_FAULT_OOM) {  in mm_fault_error()
178 		 * made us unable to handle the page fault gracefully.  in mm_fault_error()
184 		if (fault & (VM_FAULT_SIGBUS|VM_FAULT_HWPOISON|  in mm_fault_error()
186 			return do_sigbus(regs, addr, fault);  in mm_fault_error()
187 		else if (fault & VM_FAULT_SIGSEGV)  in mm_fault_error()
195 /* Is this a bad kernel fault ? */
209 		// Kernel exec fault is always bad  in bad_kernel_fault()
220 	// Kernel fault on kernel address is bad  in bad_kernel_fault()
224 	// Fault on user outside of certain regions (eg. copy_tofrom_user()) is bad  in bad_kernel_fault()
228 	// Read/write fault in a valid region (the exception table search passed  in bad_kernel_fault()
233 	// What's left? Kernel fault on user in well defined regions (extable  in bad_kernel_fault()
244 	 * faults just to hit a pkey fault as soon as we fill in a  in access_pkey_error()
282 	 * fault path, handle_mm_fault() also does the same check. To avoid  in access_error()
327 	 * fault instead of DSISR_PROTFAULT.  in sanity_check_fault()
336 	 * sync between D/I cache via fault. But that is handled via low level  in sanity_check_fault()
337 	 * hash fault code (hash_page_do_lazy_icache()) and we should not reach  in sanity_check_fault()
346 	 * set_pte_at while taking the noexec/prot fault. Hence this is WARN_ON  in sanity_check_fault()
349 	 * For radix, we can get prot fault for autonuma case, because radix  in sanity_check_fault()
382  * for a data fault, SRR1 for an instruction fault. For 400-family processors
383  * the error_code parameter is ESR for a data fault, 0 for an instruction
384  * fault.
386  *  - DSISR for a non-SLB data access fault,
387  *  - SRR1 & 0x08000000 for a non-SLB instruction access fault
388  *  - 0 any SLB fault.
390  * The return value is 0 if the fault was handled, or the signal
391  * number if this is a kernel fault that can't be handled here.
402 	vm_fault_t fault, major = 0;  in __do_page_fault()  local
420 	 * The kernel should never take an execute fault nor should it  in __do_page_fault()
421 	 * take a page fault to a kernel address or a page fault to a user  in __do_page_fault()
429 	 * in a region with pagefaults disabled then we must not take the fault  in __do_page_fault()
433 			printk_ratelimited(KERN_ERR "Page fault in user mode"  in __do_page_fault()
448 	 * can result in fault, which will cause a deadlock when called with  in __do_page_fault()
461 	 * erroneous fault occurring in a code path which already holds mmap_lock  in __do_page_fault()
462 	 * we will deadlock attempting to validate the fault against the  in __do_page_fault()
510 	 * If for any reason at all we couldn't handle the fault,  in __do_page_fault()
512 	 * the fault.  in __do_page_fault()
514 	fault = handle_mm_fault(vma, address, flags, regs);  in __do_page_fault()
516 	major |= fault & VM_FAULT_MAJOR;  in __do_page_fault()
518 	if (fault_signal_pending(fault, regs))  in __do_page_fault()
525 	if (unlikely(fault & VM_FAULT_RETRY)) {  in __do_page_fault()
534 	if (unlikely(fault & VM_FAULT_ERROR))  in __do_page_fault()
535 		return mm_fault_error(regs, address, fault);  in __do_page_fault()
538 	 * Major/minor page fault accounting.  in __do_page_fault()
567 	/* Are we prepared to handle this fault?  */  in bad_page_fault()
594 		pr_alert("BUG: Unable to handle unknown paging fault at 0x%08lx\n",  in bad_page_fault()