Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) // Copyright (C) 2005-2017 Andes Technology Corporation
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4) #include <linux/extable.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5) #include <linux/module.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6) #include <linux/signal.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7) #include <linux/ptrace.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8) #include <linux/mm.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9) #include <linux/init.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10) #include <linux/hardirq.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11) #include <linux/uaccess.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12) #include <linux/perf_event.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14) #include <asm/tlbflush.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16) extern void die(const char *str, struct pt_regs *regs, long err);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19)  * This is useful to dump out the page tables associated with
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20)  * 'addr' in mm 'mm'.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22) void show_pte(struct mm_struct *mm, unsigned long addr)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24) 	pgd_t *pgd;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25) 	if (!mm)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26) 		mm = &init_mm;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) 	pr_alert("pgd = %p\n", mm->pgd);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) 	pgd = pgd_offset(mm, addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30) 	pr_alert("[%08lx] *pgd=%08lx", addr, pgd_val(*pgd));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32) 	do {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) 		p4d_t *p4d;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) 		pud_t *pud;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35) 		pmd_t *pmd;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37) 		if (pgd_none(*pgd))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) 			break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40) 		if (pgd_bad(*pgd)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) 			pr_alert("(bad)");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42) 			break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) 		p4d = p4d_offset(pgd, addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) 		pud = pud_offset(p4d, addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) 		pmd = pmd_offset(pud, addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) #if PTRS_PER_PMD != 1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) 		pr_alert(", *pmd=%08lx", pmd_val(*pmd));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) 		if (pmd_none(*pmd))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) 			break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) 		if (pmd_bad(*pmd)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) 			pr_alert("(bad)");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) 			break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) 		if (IS_ENABLED(CONFIG_HIGHMEM))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) 		{
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) 			pte_t *pte;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) 			/* We must not map this if we have highmem enabled */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) 			pte = pte_offset_map(pmd, addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) 			pr_alert(", *pte=%08lx", pte_val(*pte));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) 			pte_unmap(pte);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) 	} while (0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) 	pr_alert("\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) void do_page_fault(unsigned long entry, unsigned long addr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74) 		   unsigned int error_code, struct pt_regs *regs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76) 	struct task_struct *tsk;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77) 	struct mm_struct *mm;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) 	struct vm_area_struct *vma;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) 	int si_code;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) 	vm_fault_t fault;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) 	unsigned int mask = VM_ACCESS_FLAGS;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) 	unsigned int flags = FAULT_FLAG_DEFAULT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84) 	error_code = error_code & (ITYPE_mskINST | ITYPE_mskETYPE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) 	tsk = current;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) 	mm = tsk->mm;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) 	si_code = SEGV_MAPERR;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) 	 * We fault-in kernel-space virtual memory on-demand. The
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) 	 * 'reference' page table is init_mm.pgd.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) 	 *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) 	 * NOTE! We MUST NOT take any locks for this case. We may
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) 	 * be in an interrupt or a critical region, and should
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) 	 * only copy the information from the master page table,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) 	 * nothing more.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) 	if (addr >= TASK_SIZE) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) 		if (user_mode(regs))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) 			goto bad_area_nosemaphore;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) 		if (addr >= TASK_SIZE && addr < VMALLOC_END
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) 		    && (entry == ENTRY_PTE_NOT_PRESENT))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) 			goto vmalloc_fault;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) 		else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) 			goto no_context;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) 	/* Send a signal to the task for handling the unalignment access. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) 	if (entry == ENTRY_GENERAL_EXCPETION
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) 	    && error_code == ETYPE_ALIGNMENT_CHECK) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) 		if (user_mode(regs))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) 			goto bad_area_nosemaphore;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) 		else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) 			goto no_context;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) 	 * If we're in an interrupt or have no user
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) 	 * context, we must not take the fault..
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) 	if (unlikely(faulthandler_disabled() || !mm))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) 		goto no_context;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) 	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) 	 * As per x86, we may deadlock here. However, since the kernel only
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) 	 * validly references user space from well defined areas of the code,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) 	 * we can bug out early if this is from code which shouldn't.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) 	if (unlikely(!mmap_read_trylock(mm))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) 		if (!user_mode(regs) &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) 		    !search_exception_tables(instruction_pointer(regs)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) 			goto no_context;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) retry:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) 		mmap_read_lock(mm);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) 	} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) 		/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 		 * The above down_read_trylock() might have succeeded in which
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 		 * case, we'll have missed the might_sleep() from down_read().
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) 		might_sleep();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 		if (IS_ENABLED(CONFIG_DEBUG_VM)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) 			if (!user_mode(regs) &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) 			    !search_exception_tables(instruction_pointer(regs)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) 				goto no_context;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) 	vma = find_vma(mm, addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) 	if (unlikely(!vma))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) 		goto bad_area;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) 	if (vma->vm_start <= addr)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 		goto good_area;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 	if (unlikely(!(vma->vm_flags & VM_GROWSDOWN)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 		goto bad_area;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) 	if (unlikely(expand_stack(vma, addr)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) 		goto bad_area;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) 	 * Ok, we have a good vm_area for this memory access, so
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) 	 * we can handle it..
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) good_area:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) 	si_code = SEGV_ACCERR;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) 	/* first do some preliminary protection checks */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) 	if (entry == ENTRY_PTE_NOT_PRESENT) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) 		if (error_code & ITYPE_mskINST)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) 			mask = VM_EXEC;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 		else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 			mask = VM_READ | VM_WRITE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) 	} else if (entry == ENTRY_TLB_MISC) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) 		switch (error_code & ITYPE_mskETYPE) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) 		case RD_PROT:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) 			mask = VM_READ;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) 			break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) 		case WRT_PROT:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) 			mask = VM_WRITE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) 			flags |= FAULT_FLAG_WRITE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) 			break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) 		case NOEXEC:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) 			mask = VM_EXEC;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) 			break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) 		case PAGE_MODIFY:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) 			mask = VM_WRITE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) 			flags |= FAULT_FLAG_WRITE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) 			break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) 		case ACC_BIT:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) 			BUG();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) 		default:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) 			break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) 	if (!(vma->vm_flags & mask))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) 		goto bad_area;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) 	 * If for any reason at all we couldn't handle the fault,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) 	 * make sure we exit gracefully rather than endlessly redo
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) 	 * the fault.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) 	fault = handle_mm_fault(vma, addr, flags, regs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) 	 * If we need to retry but a fatal signal is pending, handle the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) 	 * signal first. We do not need to release the mmap_lock because it
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) 	 * would already be released in __lock_page_or_retry in mm/filemap.c.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) 	if (fault_signal_pending(fault, regs)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) 		if (!user_mode(regs))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) 			goto no_context;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) 		return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) 	if (unlikely(fault & VM_FAULT_ERROR)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) 		if (fault & VM_FAULT_OOM)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) 			goto out_of_memory;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) 		else if (fault & VM_FAULT_SIGBUS)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) 			goto do_sigbus;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) 		else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) 			goto bad_area;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233) 	if (flags & FAULT_FLAG_ALLOW_RETRY) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) 		if (fault & VM_FAULT_RETRY) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) 			flags |= FAULT_FLAG_TRIED;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) 			/* No need to mmap_read_unlock(mm) as we would
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) 			 * have already released it in __lock_page_or_retry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239) 			 * in mm/filemap.c.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240) 			 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) 			goto retry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) 	mmap_read_unlock(mm);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246) 	return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) 	 * Something tried to access memory that isn't in our memory map..
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) 	 * Fix it, but check if it's kernel or user first..
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) bad_area:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) 	mmap_read_unlock(mm);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) bad_area_nosemaphore:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) 	/* User mode accesses just cause a SIGSEGV */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) 	if (user_mode(regs)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) 		tsk->thread.address = addr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) 		tsk->thread.error_code = error_code;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) 		tsk->thread.trap_no = entry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) 		force_sig_fault(SIGSEGV, si_code, (void __user *)addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) 		return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) no_context:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) 	/* Are we prepared to handle this kernel fault?
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270) 	 *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271) 	 * (The kernel has valid exception-points in the source
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) 	 *  when it acesses user-memory. When it fails in one
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273) 	 *  of those points, we find it in a table and do a jump
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274) 	 *  to some fixup code that loads an appropriate error
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275) 	 *  code)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 276) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 277) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 278) 	{
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 279) 		const struct exception_table_entry *entry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 280) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 281) 		if ((entry =
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 282) 		     search_exception_tables(instruction_pointer(regs))) !=
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 283) 		    NULL) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 284) 			/* Adjust the instruction pointer in the stackframe */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 285) 			instruction_pointer(regs) = entry->fixup;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 286) 			return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 287) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 288) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 289) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 290) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 291) 	 * Oops. The kernel tried to access some bad page. We'll have to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 292) 	 * terminate things with extreme prejudice.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 293) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 294) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 295) 	bust_spinlocks(1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 296) 	pr_alert("Unable to handle kernel %s at virtual address %08lx\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 297) 		 (addr < PAGE_SIZE) ? "NULL pointer dereference" :
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 298) 		 "paging request", addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 299) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 300) 	show_pte(mm, addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 301) 	die("Oops", regs, error_code);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 302) 	bust_spinlocks(0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 303) 	do_exit(SIGKILL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 304) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 305) 	return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 306) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 307) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 308) 	 * We ran out of memory, or some other thing happened to us that made
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 309) 	 * us unable to handle the page fault gracefully.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 310) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 311) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 312) out_of_memory:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 313) 	mmap_read_unlock(mm);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 314) 	if (!user_mode(regs))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 315) 		goto no_context;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 316) 	pagefault_out_of_memory();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 317) 	return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 318) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 319) do_sigbus:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 320) 	mmap_read_unlock(mm);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 321) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 322) 	/* Kernel mode? Handle exceptions or die */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 323) 	if (!user_mode(regs))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 324) 		goto no_context;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 325) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 326) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 327) 	 * Send a sigbus
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 328) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 329) 	tsk->thread.address = addr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 330) 	tsk->thread.error_code = error_code;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 331) 	tsk->thread.trap_no = entry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 332) 	force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 333) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 334) 	return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 335) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 336) vmalloc_fault:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 337) 	{
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 338) 		/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 339) 		 * Synchronize this task's top level page-table
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 340) 		 * with the 'reference' page table.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 341) 		 *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 342) 		 * Use current_pgd instead of tsk->active_mm->pgd
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 343) 		 * since the latter might be unavailable if this
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 344) 		 * code is executed in a misfortunately run irq
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 345) 		 * (like inside schedule() between switch_mm and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 346) 		 *  switch_to...).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 347) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 348) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 349) 		unsigned int index = pgd_index(addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 350) 		pgd_t *pgd, *pgd_k;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 351) 		p4d_t *p4d, *p4d_k;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 352) 		pud_t *pud, *pud_k;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 353) 		pmd_t *pmd, *pmd_k;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 354) 		pte_t *pte_k;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 355) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 356) 		pgd = (pgd_t *) __va(__nds32__mfsr(NDS32_SR_L1_PPTB)) + index;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 357) 		pgd_k = init_mm.pgd + index;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 358) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 359) 		if (!pgd_present(*pgd_k))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 360) 			goto no_context;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 361) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 362) 		p4d = p4d_offset(pgd, addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 363) 		p4d_k = p4d_offset(pgd_k, addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 364) 		if (!p4d_present(*p4d_k))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 365) 			goto no_context;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 366) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 367) 		pud = pud_offset(p4d, addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 368) 		pud_k = pud_offset(p4d_k, addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 369) 		if (!pud_present(*pud_k))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 370) 			goto no_context;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 371) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 372) 		pmd = pmd_offset(pud, addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 373) 		pmd_k = pmd_offset(pud_k, addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 374) 		if (!pmd_present(*pmd_k))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 375) 			goto no_context;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 376) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 377) 		if (!pmd_present(*pmd))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 378) 			set_pmd(pmd, *pmd_k);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 379) 		else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 380) 			BUG_ON(pmd_page(*pmd) != pmd_page(*pmd_k));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 381) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 382) 		/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 383) 		 * Since the vmalloc area is global, we don't
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 384) 		 * need to copy individual PTE's, it is enough to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 385) 		 * copy the pgd pointer into the pte page of the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 386) 		 * root task. If that is there, we'll find our pte if
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 387) 		 * it exists.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 388) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 389) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 390) 		/* Make sure the actual PTE exists as well to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 391) 		 * catch kernel vmalloc-area accesses to non-mapped
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 392) 		 * addres. If we don't do this, this will just
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 393) 		 * silently loop forever.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 394) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 395) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 396) 		pte_k = pte_offset_kernel(pmd_k, addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 397) 		if (!pte_present(*pte_k))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 398) 			goto no_context;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 399) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 400) 		return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 401) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 402) }