[src/trunk]: src/sys/arch/mips Allow kdbpeek() to return failure. If it does, ...

[bouyer <bouyer%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/af747ad159f6
branches:  trunk
changeset: 359385:af747ad159f6
user:      bouyer <bouyer%NetBSD.org@localhost>
date:      Thu Feb 08 19:16:24 2018 +0000

description:
Allow kdbpeek() to return failure. If it does, stop the stack trace.
Prevents an infinite loop in ddb if something goes wrong.

diffstat:

 sys/arch/mips/include/locore.h    |   4 ++--
 sys/arch/mips/mips/db_interface.c |  13 +++++++------
 sys/arch/mips/mips/trap.c         |  34 +++++++++++++++++++---------------
 3 files changed, 28 insertions(+), 23 deletions(-)

diffs (147 lines):

diff -r 8e9dd530c2c7 -r af747ad159f6 sys/arch/mips/include/locore.h
--- a/sys/arch/mips/include/locore.h    Thu Feb 08 18:58:59 2018 +0000
+++ b/sys/arch/mips/include/locore.h    Thu Feb 08 19:16:24 2018 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: locore.h,v 1.102 2017/03/16 16:13:20 chs Exp $ */
+/* $NetBSD: locore.h,v 1.103 2018/02/08 19:16:24 bouyer Exp $ */
 
 /*
  * This file should not be included by MI code!!!
@@ -723,7 +723,7 @@
 
 /* trap.c */
 void   netintr(void);
-int    kdbpeek(vaddr_t);
+bool   kdbpeek(vaddr_t, int *);
 
 /* mips_dsp.c */
 void   dsp_init(void);
diff -r 8e9dd530c2c7 -r af747ad159f6 sys/arch/mips/mips/db_interface.c
--- a/sys/arch/mips/mips/db_interface.c Thu Feb 08 18:58:59 2018 +0000
+++ b/sys/arch/mips/mips/db_interface.c Thu Feb 08 19:16:24 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: db_interface.c,v 1.79 2016/07/11 16:15:36 matt Exp $   */
+/*     $NetBSD: db_interface.c,v 1.80 2018/02/08 19:16:24 bouyer Exp $ */
 
 /*
  * Mach Operating System
@@ -27,7 +27,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: db_interface.c,v 1.79 2016/07/11 16:15:36 matt Exp $");
+__KERNEL_RCSID(0, "$NetBSD: db_interface.c,v 1.80 2018/02/08 19:16:24 bouyer Exp $");
 
 #include "opt_multiprocessor.h"
 #include "opt_cputype.h"       /* which mips CPUs do we support? */
@@ -96,13 +96,14 @@
 CTASSERT(sizeof(ddb_regs) == sizeof(struct reg));
 
 #ifdef DDB_TRACE
-int
-kdbpeek(vaddr_t addr)
+bool
+kdbpeek(vaddr_t addr, int *valp)
 {
 
        if (addr == 0 || (addr & 3))
-               return 0;
-       return *(int *)addr;
+               return false;
+       *valp = *(int *)addr;
+       return true;
 }
 #endif
 
diff -r 8e9dd530c2c7 -r af747ad159f6 sys/arch/mips/mips/trap.c
--- a/sys/arch/mips/mips/trap.c Thu Feb 08 18:58:59 2018 +0000
+++ b/sys/arch/mips/mips/trap.c Thu Feb 08 19:16:24 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: trap.c,v 1.245 2017/12/22 22:59:25 maya Exp $  */
+/*     $NetBSD: trap.c,v 1.246 2018/02/08 19:16:24 bouyer Exp $        */
 
 /*
  * Copyright (c) 1988 University of Utah.
@@ -39,7 +39,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.245 2017/12/22 22:59:25 maya Exp $");
+__KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.246 2018/02/08 19:16:24 bouyer Exp $");
 
 #include "opt_cputype.h"       /* which mips CPU levels do we support? */
 #include "opt_ddb.h"
@@ -748,23 +748,20 @@
 #if defined(DEBUG) || defined(DDB) || defined(KGDB) || defined(geo)
 mips_reg_t kdbrpeek(vaddr_t, size_t);
 
-int
-kdbpeek(vaddr_t addr)
+bool
+kdbpeek(vaddr_t addr, int *valp)
 {
-       int rc;
-
        if (addr & 3) {
                printf("kdbpeek: unaligned address %#"PRIxVADDR"\n", addr);
                /* We might have been called from DDB, so do not go there. */
-               stacktrace();
-               rc = -1 ;
+               return false;
        } else if (addr == 0) {
                printf("kdbpeek: NULL\n");
-               rc = 0xdeadfeed;
+               return false;
        } else {
-               rc = *(int *)addr;
+               *valp = *(int *)addr;
+               return true;
        }
-       return rc;
 }
 
 mips_reg_t
@@ -909,7 +906,8 @@
        sym = db_search_symbol(pc, DB_STGY_ANY, &diff);
        if (sym != DB_SYM_NULL && diff == 0) {
                /* check func(foo) __attribute__((__noreturn__)) case */
-               instr = kdbpeek(pc - 2 * sizeof(int));
+               if (!kdbpeek(pc - 2 * sizeof(int), &instr))
+                       return;
                i.word = instr;
                if (i.JType.op == OP_JAL) {
                        sym = db_search_symbol(pc - sizeof(int),
@@ -937,7 +935,8 @@
                va -= sizeof(int);
                if (va <= (vaddr_t)verylocore)
                        goto finish;
-               instr = kdbpeek(va);
+               if (!kdbpeek(va, &instr))
+                       return;
                if (instr == MIPS_ERET)
                        goto mips3_eret;
        } while (instr != MIPS_JR_RA && instr != MIPS_JR_K0);
@@ -946,8 +945,12 @@
 mips3_eret:
        va += sizeof(int);
        /* skip over nulls which might separate .o files */
-       while ((instr = kdbpeek(va)) == 0)
+       instr = 0;
+       while (instr == 0) {
+               if (!kdbpeek(va, &instr))
+                       return;
                va += sizeof(int);
+       }
 #endif
        subr = va;
 
@@ -961,7 +964,8 @@
                /* stop if hit our current position */
                if (va >= pc)
                        break;
-               instr = kdbpeek(va);
+               if (!kdbpeek(va, &instr))
+                       return;
                i.word = instr;
                switch (i.JType.op) {
                case OP_SPECIAL: