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hc

2023-12-11 072de836f53be56a70cecf70b43ae43b7ce17376

 kernel/arch/parisc/mm/fault.c
..
..
@@ -18,6 +18,7 @@
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18
 #include <linux/extable.h>
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19
 #include <linux/uaccess.h>
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 #include <linux/hugetlb.h>
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+#include <linux/perf_event.h>
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22
 
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 #include <asm/traps.h>
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24
 
..
..
@@ -66,6 +67,7 @@
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 	case 0x30000000: /* coproc2 */
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 		if (bit22set(inst))
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 			return VM_WRITE;
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+		fallthrough;
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71
 
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 	case 0x0: /* indexed/memory management */
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 		if (bit22set(inst)) {
..
..
@@ -273,15 +275,16 @@
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 	if (!mm)
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 		goto no_context;
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-	flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
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+	flags = FAULT_FLAG_DEFAULT;
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 	if (user_mode(regs))
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280
 		flags |= FAULT_FLAG_USER;
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281
 
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 	acc_type = parisc_acctyp(code, regs->iir);
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 	if (acc_type & VM_WRITE)
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 		flags |= FAULT_FLAG_WRITE;
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+	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
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 retry:
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-	down_read(&mm->mmap_sem);
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+	mmap_read_lock(mm);
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 	vma = find_vma_prev(mm, address, &prev_vma);
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 	if (!vma || address < vma->vm_start)
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 		goto check_expansion;
..
..
@@ -301,9 +304,9 @@
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 	 * fault.
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305
 	 */
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306
 
304
-	fault = handle_mm_fault(vma, address, flags);
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+	fault = handle_mm_fault(vma, address, flags, regs);
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308
 
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-	if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
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+	if (fault_signal_pending(fault, regs))
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 		return;
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311
 
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 	if (unlikely(fault & VM_FAULT_ERROR)) {
..
..
@@ -322,23 +325,17 @@
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 		BUG();
323
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 	}
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 	if (flags & FAULT_FLAG_ALLOW_RETRY) {
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-		if (fault & VM_FAULT_MAJOR)
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-			current->maj_flt++;
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-		else
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-			current->min_flt++;
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328
 		if (fault & VM_FAULT_RETRY) {
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-			flags &= ~FAULT_FLAG_ALLOW_RETRY;
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-
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 			/*
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-			 * No need to up_read(&mm->mmap_sem) as we would
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+			 * No need to mmap_read_unlock(mm) as we would
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 			 * have already released it in __lock_page_or_retry
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 			 * in mm/filemap.c.
336
333
 			 */
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-
334
+			flags |= FAULT_FLAG_TRIED;
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 			goto retry;
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336
 		}
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 	}
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-	up_read(&mm->mmap_sem);
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+	mmap_read_unlock(mm);
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339
 	return;
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340
 
344
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 check_expansion:
..
..
@@ -350,7 +347,7 @@
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  * Something tried to access memory that isn't in our memory map..
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  */
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 bad_area:
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-	up_read(&mm->mmap_sem);
350
+	mmap_read_unlock(mm);
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351
 
355
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 	if (user_mode(regs)) {
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353
 		int signo, si_code;
..
..
@@ -373,7 +370,7 @@
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 			}
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371
 
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 			/* probably address is outside of mapped file */
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-			/* fall through */
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+			fallthrough;
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 		case 17:	/* NA data TLB miss / page fault */
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 		case 18:	/* Unaligned access - PCXS only */
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 			signo = SIGBUS;
..
..
@@ -403,13 +400,13 @@
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 				lsb = PAGE_SHIFT;
404
401
 
405
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 			force_sig_mceerr(BUS_MCEERR_AR, (void __user *) address,
406
-					 lsb, current);
403
+					 lsb);
407
404
 			return;
408
405
 		}
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 #endif
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 		show_signal_msg(regs, code, address, tsk, vma);
411
408
 
412
-		force_sig_fault(signo, si_code, (void __user *) address, current);
409
+		force_sig_fault(signo, si_code, (void __user *) address);
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 		return;
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411
 	}
415
412
 
..
..
@@ -422,8 +419,97 @@
422
419
 	parisc_terminate("Bad Address (null pointer deref?)", regs, code, address);
423
420
 
424
421
   out_of_memory:
425
-	up_read(&mm->mmap_sem);
422
+	mmap_read_unlock(mm);
426
423
 	if (!user_mode(regs))
427
424
 		goto no_context;
428
425
 	pagefault_out_of_memory();
429
426
 }
427
+
428
+/* Handle non-access data TLB miss faults.
429
+ *
430
+ * For probe instructions, accesses to userspace are considered allowed
431
+ * if they lie in a valid VMA and the access type matches. We are not
432
+ * allowed to handle MM faults here so there may be situations where an
433
+ * actual access would fail even though a probe was successful.
434
+ */
435
+int
436
+handle_nadtlb_fault(struct pt_regs *regs)
437
+{
438
+	unsigned long insn = regs->iir;
439
+	int breg, treg, xreg, val = 0;
440
+	struct vm_area_struct *vma, *prev_vma;
441
+	struct task_struct *tsk;
442
+	struct mm_struct *mm;
443
+	unsigned long address;
444
+	unsigned long acc_type;
445
+
446
+	switch (insn & 0x380) {
447
+	case 0x280:
448
+		/* FDC instruction */
449
+		fallthrough;
450
+	case 0x380:
451
+		/* PDC and FIC instructions */
452
+		if (printk_ratelimit()) {
453
+			pr_warn("BUG: nullifying cache flush/purge instruction\n");
454
+			show_regs(regs);
455
+		}
456
+		if (insn & 0x20) {
457
+			/* Base modification */
458
+			breg = (insn >> 21) & 0x1f;
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+			xreg = (insn >> 16) & 0x1f;
460
+			if (breg && xreg)
461
+				regs->gr[breg] += regs->gr[xreg];
462
+		}
463
+		regs->gr[0] |= PSW_N;
464
+		return 1;
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+
466
+	case 0x180:
467
+		/* PROBE instruction */
468
+		treg = insn & 0x1f;
469
+		if (regs->isr) {
470
+			tsk = current;
471
+			mm = tsk->mm;
472
+			if (mm) {
473
+				/* Search for VMA */
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+				address = regs->ior;
475
+				mmap_read_lock(mm);
476
+				vma = find_vma_prev(mm, address, &prev_vma);
477
+				mmap_read_unlock(mm);
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+
479
+				/*
480
+				 * Check if access to the VMA is okay.
481
+				 * We don't allow for stack expansion.
482
+				 */
483
+				acc_type = (insn & 0x40) ? VM_WRITE : VM_READ;
484
+				if (vma
485
+				    && address >= vma->vm_start
486
+				    && (vma->vm_flags & acc_type) == acc_type)
487
+					val = 1;
488
+			}
489
+		}
490
+		if (treg)
491
+			regs->gr[treg] = val;
492
+		regs->gr[0] |= PSW_N;
493
+		return 1;
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+
495
+	case 0x300:
496
+		/* LPA instruction */
497
+		if (insn & 0x20) {
498
+			/* Base modification */
499
+			breg = (insn >> 21) & 0x1f;
500
+			xreg = (insn >> 16) & 0x1f;
501
+			if (breg && xreg)
502
+				regs->gr[breg] += regs->gr[xreg];
503
+		}
504
+		treg = insn & 0x1f;
505
+		if (treg)
506
+			regs->gr[treg] = 0;
507
+		regs->gr[0] |= PSW_N;
508
+		return 1;
509
+
510
+	default:
511
+		break;
512
+	}
513
+
514
+	return 0;
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+}