Fix the "fake" frame that we create alongside the trapframe. This fixes

backtraces through trap franes.  Adjust the code that prints backtraces
in ddb as the old code now tries to access a userland address.

ok mpi@

diff --git a/sys/arch/arm64/arm64/db_trace.c b/sys/arch/arm64/arm64/db_trace.c
index 0fcfa13..cd46053 100644 (file)
--- a/sys/arch/arm64/arm64/db_trace.c
+++ b/sys/arch/arm64/arm64/db_trace.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: db_trace.c,v 1.15 2023/06/17 08:13:56 kettenis Exp $  */
+/*     $OpenBSD: db_trace.c,v 1.16 2024/03/12 13:32:53 kettenis Exp $  */
 /*     $NetBSD: db_trace.c,v 1.8 2003/01/17 22:28:48 thorpej Exp $     */
 
 /*
@@ -97,8 +97,13 @@ db_stack_trace_print(db_expr_t addr, int have_addr, db_expr_t count,
        while (count-- && frame != 0) {
                lastframe = frame;
 
-               sym = db_search_symbol(lastlr, DB_STGY_ANY, &offset);
-               db_symbol_values(sym, &name, NULL);
+               if (INKERNEL(frame)) {
+                       sym = db_search_symbol(lastlr, DB_STGY_ANY, &offset);
+                       db_symbol_values(sym, &name, NULL);
+               } else {
+                       sym = NULL;
+                       name = NULL;
+               }
 
                if (name == NULL || strcmp(name, "end") == 0) {
                        (*pr)("%llx at 0x%lx", lastlr, lr - 4);
@@ -108,13 +113,6 @@ db_stack_trace_print(db_expr_t addr, int have_addr, db_expr_t count,
                }
                (*pr)("\n");
 
-               // can we detect traps ?
-               db_read_bytes(frame, sizeof(vaddr_t), (char *)&frame);
-               if (frame == 0)
-                       break;
-               lastlr = lr;
-               db_read_bytes(frame + 8, sizeof(vaddr_t), (char *)&lr);
-
                if (name != NULL) {
                        if ((strcmp (name, "handle_el0_irq") == 0) ||
                            (strcmp (name, "handle_el1_irq") == 0)) {
@@ -125,15 +123,39 @@ db_stack_trace_print(db_expr_t addr, int have_addr, db_expr_t count,
                                (*pr)("--- trap ---\n");
                        }
                }
+
+               lastframe = frame;
+               db_read_bytes(frame, sizeof(vaddr_t), (char *)&frame);
+
+               if (frame == 0) {
+                       /* end of chain */
+                       break;
+               }
+
                if (INKERNEL(frame)) {
+                       /* staying in kernel */
                        if (frame <= lastframe) {
                                (*pr)("Bad frame pointer: 0x%lx\n", frame);
                                break;
                        }
+               } else if (INKERNEL(lastframe)) {
+                       /* switch from user to kernel */
+                       if (kernel_only) {
+                               (*pr)("end of kernel\n");
+                               break;  /* kernel stack only */
+                       }
                } else {
-                       if (kernel_only)
+                       /* in user */
+                       if (frame <= lastframe) {
+                               (*pr)("Bad user frame pointer: 0x%lx\n",
+                                       frame);
                                break;
+                       }
                }
+
+               lastlr = lr;
+               db_read_bytes(frame + 8, sizeof(vaddr_t), (char *)&lr);
+
                --count;
        }
 }

diff --git a/sys/arch/arm64/arm64/exception.S b/sys/arch/arm64/arm64/exception.S
index 1a1ff5f..101de9e 100644 (file)
--- a/sys/arch/arm64/arm64/exception.S
+++ b/sys/arch/arm64/arm64/exception.S
@@ -1,4 +1,4 @@
-/* $OpenBSD: exception.S,v 1.16 2023/12/26 09:19:15 kettenis Exp $ */
+/* $OpenBSD: exception.S,v 1.17 2024/03/12 13:32:53 kettenis Exp $ */
 /*-
  * Copyright (c) 2014 Andrew Turner
  * All rights reserved.
@@ -38,7 +38,6 @@
        sub     sp, sp, #128
 .endif
        sub     sp, sp, #(TF_SIZE + 16)
-       stp     x29, x30, [sp, #(TF_SIZE)]
        stp     x28, x29, [sp, #(TF_X + 28 * 8)]
        stp     x26, x27, [sp, #(TF_X + 26 * 8)]
        stp     x24, x25, [sp, #(TF_X + 24 * 8)]
@@ -59,11 +58,11 @@
 .if \el == 0
        mrs     x18, sp_el0
 .endif
-       mov     fp, x18
        stp     x10, x11, [sp, #(TF_ELR)]
        stp     x18, lr, [sp, #(TF_SP)]
+       stp     fp, x10, [sp, #(TF_SIZE)]
        mrs     x18, tpidr_el1
-       add     x29, sp, #(TF_SIZE)
+       add     fp, sp, #(TF_SIZE)
 .endm
 
 .macro restore_registers el