Dave,

On Wed, Oct 18, 2017 at 02:12:17PM -0400, Dave Anderson wrote:
> 
> 
> ----- Original Message -----
> > On Tue, Oct 17, 2017 at 03:44:36PM -0400, Dave Anderson wrote:
> > > 
> > > Thanks Takahiro, much appreciated.  Queued for crash-7.2.1:
> > >  
> > >   
> > > https://github.com/crash-utility/crash/commit/2b93c036edf2a5cc21a06a14f377cd9b365f858a
> > 
> > Oops, I've made small changes, nothing essential but some sort of
> > clean-ups/readability improvements with deleting incomplete fixes
> > against "bt -o."
> 
> Hmmm, except it's kind of difficult to pick through the patch below
> for the changes, given that it's a combination of your original patch
> plus the new changes.  So I can't apply it to get a clean view of
> the new changes.  I do see that it's mostly the stacksize and stackframe
> related updates, but would it be possible for you to make a patch
> that can be applied to the github sources?

Here is what you requested. Pls check.

Thanks,
-Takahiro AKASHI

===8<===
>From 7b99a1c2e688ba81e18541c21a7d0fa70504e5bc Mon Sep 17 00:00:00 2001
From: AKASHI Takahiro <takahiro.aka...@linaro.org>
Date: Thu, 19 Oct 2017 10:18:22 +0900
Subject: [PATCH] arm64: bt: cleanup stuff

---
 arm64.c | 159 +++++++++++++++++++++++++++++++++-------------------------------
 defs.h  |   3 ++
 task.c  |   2 +
 3 files changed, 86 insertions(+), 78 deletions(-)

diff --git a/arm64.c b/arm64.c
index c75669b..1f742d4 100644
--- a/arm64.c
+++ b/arm64.c
@@ -612,6 +612,7 @@ arm64_dump_machdep_table(ulong arg)
        fprintf(fp, "        exp_entry2_end: %lx\n", ms->exp_entry2_end);
        fprintf(fp, "       panic_task_regs: %lx\n", 
(ulong)ms->panic_task_regs);
        fprintf(fp, "    user_eframe_offset: %ld\n", ms->user_eframe_offset);
+       fprintf(fp, "    kern_eframe_offset: %ld\n", ms->kern_eframe_offset);
        fprintf(fp, "         PTE_PROT_NONE: %lx\n", ms->PTE_PROT_NONE);
        fprintf(fp, "              PTE_FILE: ");
        if (ms->PTE_FILE)
@@ -1383,7 +1384,7 @@ arm64_irq_stack_init(void)
 
                if (!(ms->irq_stacks = (ulong *)malloc((size_t)(kt->cpus * 
sizeof(ulong)))))
                        error(FATAL, "cannot malloc irq_stack addresses\n");
-               ms->irq_stack_size = 16384;
+               ms->irq_stack_size = ARM64_IRQ_STACK_SIZE;
                machdep->flags |= IRQ_STACKS;
 
                for (i = 0; i < kt->cpus; i++) {
@@ -1410,10 +1411,13 @@ arm64_stackframe_init(void)
        MEMBER_OFFSET_INIT(elf_prstatus_pr_pid, "elf_prstatus", "pr_pid");
        MEMBER_OFFSET_INIT(elf_prstatus_pr_reg, "elf_prstatus", "pr_reg");
 
-       if (MEMBER_EXISTS("pt_regs", "stackframe")) 
+       if (MEMBER_EXISTS("pt_regs", "stackframe")) {
                machdep->machspec->user_eframe_offset = SIZE(pt_regs);
-       else
+               machdep->machspec->kern_eframe_offset = SIZE(pt_regs) - 16;
+       } else {
                machdep->machspec->user_eframe_offset = SIZE(pt_regs) + 16;
+               machdep->machspec->kern_eframe_offset = SIZE(pt_regs);
+       }
 
        machdep->machspec->__exception_text_start = 
                symbol_value("__exception_text_start");
@@ -1503,6 +1507,7 @@ arm64_stackframe_init(void)
 #define USER_MODE   (2)
 
 #define USER_EFRAME_OFFSET (machdep->machspec->user_eframe_offset)
+#define KERN_EFRAME_OFFSET (machdep->machspec->kern_eframe_offset)
 
 /*
  * PSR bits
@@ -1778,7 +1783,7 @@ arm64_display_full_frame(struct bt_info *bt, ulong sp)
        ulong words, addr;
        char buf[BUFSIZE];
 
-       if (bt->frameptr == sp)
+       if (bt->frameptr >= sp)
                return;
 
        if (INSTACK(bt->frameptr, bt)) {
@@ -1793,7 +1798,7 @@ arm64_display_full_frame(struct bt_info *bt, ulong sp)
                                sp = bt->stacktop;
                }
        } else { 
-               /* IRQ exception frame */
+               /* This is a transition case from irq to process stack. */
                return;
        }
 
@@ -1903,61 +1908,73 @@ arm64_unwind_frame(struct bt_info *bt, struct 
arm64_stackframe *frame)
        if (!(machdep->flags & IRQ_STACKS))
                return TRUE;
 
-       /*
-        * The kernel's manner of determining the end of the IRQ stack:
-        *
-        *  #define THREAD_SIZE        16384
-        *  #define THREAD_START_SP    (THREAD_SIZE - 16)
-        *  #define IRQ_STACK_START_SP THREAD_START_SP
-        *  #define IRQ_STACK_PTR(cpu) ((unsigned long)per_cpu(irq_stack, cpu) 
+ IRQ_STACK_START_SP)
-        *  #define IRQ_STACK_TO_TASK_STACK(ptr) (*((unsigned long *)((ptr) - 
0x08)))
-        *
-        *  irq_stack_ptr = IRQ_STACK_PTR(raw_smp_processor_id());
-        *  orig_sp = IRQ_STACK_TO_TASK_STACK(irq_stack_ptr);   (pt_regs 
pointer on process stack)
-        */
+       if (!(machdep->flags & IRQ_STACKS))
+               return TRUE;
+
        if (machdep->flags & UNW_4_14) {
                if ((bt->flags & BT_IRQSTACK) &&
                    !arm64_on_irq_stack(bt->tc->processor, frame->fp)) {
                        if (arm64_on_process_stack(bt, frame->fp)) {
                                arm64_set_process_stack(bt);
 
-                               frame->sp = frame->fp - SIZE(pt_regs) + 16;
-                               /* for switch_stack */
-                               /* fp still points to irq stack */
+                               frame->sp = frame->fp - KERN_EFRAME_OFFSET;
+                               /*
+                                * for switch_stack
+                                * fp still points to irq stack
+                                */
                                bt->bptr = fp;
-                               /* for display_full_frame */
-                               /* sp points to process stack */
-                               bt->frameptr = frame->sp;
+                               /*
+                                * for display_full_frame
+                                * sp points to process stack
+                                *
+                                * If we want to see pt_regs,
+                                * comment out the below.
+                                * bt->frameptr = frame->sp;
+                                */
                        } else {
                                /* irq -> user */
                                return FALSE;
                        }
                }
-       } else { /* !UNW_4_14 */
-               ms = machdep->machspec;
-               irq_stack_ptr = ms->irq_stacks[bt->tc->processor] + 
ms->irq_stack_size - 16;
-
-               if (frame->sp == irq_stack_ptr) {
-                       orig_sp = GET_STACK_ULONG(irq_stack_ptr - 8);
-                       arm64_set_process_stack(bt);
-                       if (INSTACK(orig_sp, bt) && (INSTACK(frame->fp, bt) || 
(frame->fp == 0))) {
-                               ptregs = (struct arm64_pt_regs 
*)&bt->stackbuf[(ulong)(STACK_OFFSET_TYPE(orig_sp))];
-                               frame->sp = orig_sp;
-                               frame->pc = ptregs->pc;
-                               bt->bptr = fp;
-                               if (CRASHDEBUG(1))
-                                       error(INFO, 
-                                           "arm64_unwind_frame: switch stacks: 
fp: %lx sp: %lx  pc: %lx\n",
-                                               frame->fp, frame->sp, 
frame->pc);
-                       } else {
-                               error(WARNING, 
-                                   "arm64_unwind_frame: on IRQ stack: oriq_sp: 
%lx%s fp: %lx%s\n",
-                                       orig_sp, INSTACK(orig_sp, bt) ? "" : " 
(?)",
-                                       frame->fp, INSTACK(frame->fp, bt) ? "" 
: " (?)");
-                               return FALSE;
-                       }
+
+               return TRUE;
+       }
+
+       /*
+        * The kernel's manner of determining the end of the IRQ stack:
+        *
+        *  #define THREAD_SIZE        16384
+        *  #define THREAD_START_SP    (THREAD_SIZE - 16)
+        *  #define IRQ_STACK_START_SP THREAD_START_SP
+        *  #define IRQ_STACK_PTR(cpu) ((unsigned long)per_cpu(irq_stack, cpu) 
+ IRQ_STACK_START_SP)
+        *  #define IRQ_STACK_TO_TASK_STACK(ptr) (*((unsigned long *)((ptr) - 
0x08)))
+        *
+        *  irq_stack_ptr = IRQ_STACK_PTR(raw_smp_processor_id());
+        *  orig_sp = IRQ_STACK_TO_TASK_STACK(irq_stack_ptr);   (pt_regs 
pointer on process stack)
+        */
+       ms = machdep->machspec;
+       irq_stack_ptr = ms->irq_stacks[bt->tc->processor] + ms->irq_stack_size 
- 16;
+
+       if (frame->sp == irq_stack_ptr) {
+               orig_sp = GET_STACK_ULONG(irq_stack_ptr - 8);
+               arm64_set_process_stack(bt);
+               if (INSTACK(orig_sp, bt) && (INSTACK(frame->fp, bt) || 
(frame->fp == 0))) {
+                       ptregs = (struct arm64_pt_regs 
*)&bt->stackbuf[(ulong)(STACK_OFFSET_TYPE(orig_sp))];
+                       frame->sp = orig_sp;
+                       frame->pc = ptregs->pc;
+                       bt->bptr = fp;
+                       if (CRASHDEBUG(1))
+                               error(INFO,
+                                   "arm64_unwind_frame: switch stacks: fp: %lx 
sp: %lx  pc: %lx\n",
+                                       frame->fp, frame->sp, frame->pc);
+               } else {
+                       error(WARNING,
+                           "arm64_unwind_frame: on IRQ stack: oriq_sp: %lx%s 
fp: %lx%s\n",
+                               orig_sp, INSTACK(orig_sp, bt) ? "" : " (?)",
+                               frame->fp, INSTACK(frame->fp, bt) ? "" : " 
(?)");
+                       return FALSE;
                }
-       } /* UNW_4_14 */
+       }
 
        return TRUE;
 }
@@ -2147,17 +2164,10 @@ arm64_unwind_frame_v2(struct bt_info *bt, struct 
arm64_stackframe *frame,
                         * We are on process stack. Just add a faked frame
                         */
 
-                       if (!arm64_on_irq_stack(bt->tc->processor, 
ext_frame.fp)) {
-                               if (MEMBER_EXISTS("pt_regs", "stackframe")) {
-                                       frame->sp = ext_frame.fp
-                                                   - sizeof(struct 
arm64_pt_regs) - 16;
-                                       frame->fp = ext_frame.fp;
-                               } else {
-                                       frame->sp = ext_frame.fp
-                                                   - sizeof(struct 
arm64_pt_regs);
-                                       frame->fp = frame->sp;
-                               }
-                       } else {
+                       if (!arm64_on_irq_stack(bt->tc->processor, 
ext_frame.fp))
+                               frame->sp = ext_frame.fp
+                                           - sizeof(struct arm64_pt_regs);
+                       else {
                                /*
                                 * FIXME: very exceptional case
                                 * We are already back on process stack, but
@@ -2177,10 +2187,10 @@ arm64_unwind_frame_v2(struct bt_info *bt, struct 
arm64_stackframe *frame,
                                 * Really ugly
                                 */
                                frame->sp = frame->fp + 0x20;
-                               frame->fp = frame->sp;
                                fprintf(ofp, " (Next exception frame might be 
wrong)\n");
                        }
 
+                       frame->fp = frame->sp;
                } else {
                        /* We are on IRQ stack */
 
@@ -2190,15 +2200,9 @@ arm64_unwind_frame_v2(struct bt_info *bt, struct 
arm64_stackframe *frame,
                        if (ext_frame.fp != irq_stack_ptr) {
                                /* (2) Just add a faked frame */
 
-                               if (MEMBER_EXISTS("pt_regs", "stackframe")) {
-                                       frame->sp = ext_frame.fp
-                                                   - sizeof(struct 
arm64_pt_regs);
-                                       frame->fp = ext_frame.fp;
-                               } else {
-                                       frame->sp = ext_frame.fp
-                                                   - sizeof(struct 
arm64_pt_regs) - 16;
-                                       frame->fp = frame->sp;
-                               }
+                               frame->sp = ext_frame.fp
+                                           - sizeof(struct arm64_pt_regs);
+                               frame->fp = frame->sp;
                        } else {
                                /*
                                 * (3)
@@ -2285,6 +2289,11 @@ arm64_back_trace_cmd(struct bt_info *bt)
        FILE *ofp;
 
        if (bt->flags & BT_OPT_BACK_TRACE) {
+               if (machdep->flags & UNW_4_14) {
+                       error(WARNING, "\"-o\" is no longer supported for this 
version of kernel. Please use bt\n");
+                       return;
+               }
+
                arm64_back_trace_cmd_v2(bt);
                return;
        }
@@ -2346,7 +2355,7 @@ arm64_back_trace_cmd(struct bt_info *bt)
                        goto complete_user;
 
                if (DUMPFILE() && is_task_active(bt->task)) {
-                       exception_frame = stackframe.fp - SIZE(pt_regs);
+                       exception_frame = stackframe.fp - KERN_EFRAME_OFFSET;
                        if (arm64_is_kernel_exception_frame(bt, 
exception_frame))
                                arm64_print_exception_frame(bt, 
exception_frame, 
                                        KERNEL_MODE, ofp);
@@ -2377,13 +2386,9 @@ arm64_back_trace_cmd(struct bt_info *bt)
 
                if (arm64_in_exception_text(bt->instptr) && 
INSTACK(stackframe.fp, bt)) {
                        if (!(bt->flags & BT_IRQSTACK) ||
-                           (((stackframe.sp + SIZE(pt_regs)) < bt->stacktop))) 
{
-                               if (MEMBER_EXISTS("pt_regs", "stackframe"))
-                                       /* v4.14 or later */
-                                       exception_frame = stackframe.fp - 
SIZE(pt_regs) + 16;
-                               else
-                                       exception_frame = stackframe.fp - 
SIZE(pt_regs);
-                       }
+                           (((stackframe.sp + SIZE(pt_regs)) < bt->stacktop)))
+                               exception_frame = stackframe.fp
+                                                 - KERN_EFRAME_OFFSET;
                }
 
                if ((bt->flags & BT_IRQSTACK) &&
@@ -2503,8 +2508,6 @@ user_space:
                 * otherwise show an exception frame.
                 * Since exception entry code doesn't have a real
                 * stackframe, we fake a dummy frame here.
-                * Note: Since we have a real stack frame in pt_regs,
-                * We no longer need a dummy frame on v4.14 or later.
                 */
                if (!arm64_in_exp_entry(stackframe.pc))
                        continue;
diff --git a/defs.h b/defs.h
index 7768895..a694a66 100644
--- a/defs.h
+++ b/defs.h
@@ -3038,6 +3038,7 @@ typedef signed int s32;
 #define ARM64_VMEMMAP_END    (ARM64_VMEMMAP_VADDR + GIGABYTES(8UL) - 1)
 
 #define ARM64_STACK_SIZE   (16384)
+#define ARM64_IRQ_STACK_SIZE   ARM64_STACK_SIZE
 
 #define _SECTION_SIZE_BITS      30
 #define _MAX_PHYSMEM_BITS       40
@@ -3117,6 +3118,8 @@ struct machine_specific {
        ulong kimage_text;
        ulong kimage_end;
        ulong user_eframe_offset;
+       /* for v4.14 or later */
+       ulong kern_eframe_offset;
 };
 
 struct arm64_stackframe {
diff --git a/task.c b/task.c
index 2b12af0..23c2b7b 100644
--- a/task.c
+++ b/task.c
@@ -6750,6 +6750,8 @@ panic_search(void)
        fd->keyword_array[0] = FOREACH_BT; 
        if (machine_type("S390X"))
                fd->flags |= FOREACH_o_FLAG;
+       else if (machine_type("ARM64") && (machdep->flags & UNW_4_14))
+               fd->flags |= FOREACH_t_FLAG;
        else
                fd->flags |= (FOREACH_t_FLAG|FOREACH_o_FLAG);
 
-- 
2.14.1

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