On Tue, Jun 21, 2016 at 04:52:32PM -0400, Dave Anderson wrote:
> 
> > Dave,
> > 
> > This patch addresses all the issues that I mentioned in [1], and
> > re-factored arm64_back_trace_cmd() to make it simpler, while
> > arm64_unwind_frame() gets a bit complicated. But those changes,
> > I believe, make the code more readable and easily maintainable.
> > (The only ugly part is arm64_in_exp_entry(). I have no better ideas.)
> > 
> > Please pick up this patch if you like.
> > It is to be applied on top of your current master.
> > 
> > [1] https://www.redhat.com/archives/crash-utility/2016-June/msg00040.html
> > 
> > Thanks,
> > -Takahiro AKASHI
> 
> Takahiro,
> 
> I hope to be able to take a look at this tomorrow, but upon an initial 
> compile,
> there's an error at line 1782 that prevents a chunk of code from ever being
> executed:
> 
> # make warn

Oops, I forget to run "make warn" again.

> ... [ cut ] ...
> cc -c -g -DARM64 -DLZO -DSNAPPY -DGDB_7_6  arm64.c -Wall -O2 
> -Wstrict-prototypes -Wmissing-prototypes -fstack-protector -Wformat-security 
> arm64.c: In function 'arm64_unwind_frame':
> arm64.c:1782:14: warning: suggest parentheses around operand of '!' or change 
> '&' to '&& or '!' to '~' [-Wparentheses]
>    } else if (!machdep->flags & IRQ_STACKS) {
>               ^
> arm64.c:1729:31: warning: unused variable 'orig_sp' [-Wunused-variable]
>   unsigned long irq_stack_ptr, orig_sp;
>                                ^
> arm64.c: At top level:
> arm64.c:1489:1: warning: 'arm64_in_exception_text' defined but not used 
> [-Wunused-function]
>  arm64_in_exception_text(ulong ptr)
>  ^
> ...

Fixed them. 

> Here it is:
> 
>    1773                 if (ext_frame.fp == 0) {
>    1774                         /*
>    1775                          * Either on process stack or on IRQ stack,
>    1776                          * the next frame is the last one on process 
> stack.
>    1777                          */
>    1778 
>    1779                         frame->sp = bt->stacktop
>    1780                                     - sizeof(struct arm64_pt_regs) - 
> 0x10;
>    1781                         frame->fp = frame->sp;
>    1782                 } else if (!machdep->flags & IRQ_STACKS) {
>    1783                         /*
>    1784                          * We are on process stack. Just fake a dummy 
> frame
>    1785                          */
>    1786 
>    1787                         frame->sp = ext_frame.fp
>    1788                                     - sizeof(struct arm64_pt_regs);
>    1789                         frame->fp = frame->sp;
>    1790                 } else {
>    1791                         /* We are on IRQ stack */
>    1792 
>    1793                         ms = machdep->machspec;
>    1794                         irq_stack_ptr = 
> ms->irq_stacks[bt->tc->processor]
>    1795                                                 + ms->irq_stack_size 
> - 0x20;
>    1796    
> 
> I know what it should look like, but I can't understand how the code works 
> as-is?

I can't neither :)
You're right. I mistakenly used IRQ_STACKS here.

Please review my next version.
(I'm now testing crash util with various vmcore's, and
have faced some corner cases.)

Thanks,
-Takahiro AKASHI

> Dave
> 
> 
> 
> 
> 
> > 
> > ======8<======
> > >From c1e06fdd21bb70d247babd43cf2762e0cdf6979c Mon Sep 17 00:00:00 2001
> > From: AKASHI Takahiro <[email protected]>
> > Date: Thu, 16 Jun 2016 09:29:52 +0900
> > Subject: [PATCH v3] arm64: more improvement of bt -f
> > 
> > Signed-off-by: AKASHI Takahiro <[email protected]>
> > ---
> >  arm64.c | 486
> >  +++++++++++++++++++++++++++++++++++++++++++---------------------
> >  defs.h  |   6 +
> >  2 files changed, 337 insertions(+), 155 deletions(-)
> > 
> > diff --git a/arm64.c b/arm64.c
> > index 06676d1..9d42fe6 100644
> > --- a/arm64.c
> > +++ b/arm64.c
> > @@ -43,17 +43,18 @@ static void arm64_stackframe_init(void);
> >  static int arm64_eframe_search(struct bt_info *);
> >  static int arm64_is_kernel_exception_frame(struct bt_info *, ulong);
> >  static int arm64_in_exception_text(ulong);
> > +static int arm64_in_exp_entry(ulong);
> >  static void arm64_back_trace_cmd(struct bt_info *);
> >  static void arm64_print_text_symbols(struct bt_info *, struct
> >  arm64_stackframe *, FILE *);
> >  static int arm64_print_stackframe_entry(struct bt_info *, int, struct
> >  arm64_stackframe *, FILE *);
> > -static void arm64_display_full_frame(struct bt_info *, ulong);
> > -static int arm64_unwind_frame(struct bt_info *, struct arm64_stackframe *);
> > +static void arm64_display_full_frame(struct bt_info *, struct
> > arm64_stackframe *, struct arm64_stackframe *);
> > +static int arm64_unwind_frame(struct bt_info *, struct arm64_stackframe *,
> > FILE *);
> >  static int arm64_get_dumpfile_stackframe(struct bt_info *, struct
> >  arm64_stackframe *);
> >  static int arm64_in_kdump_text(struct bt_info *, struct arm64_stackframe 
> > *);
> >  static int arm64_in_kdump_text_on_irq_stack(struct bt_info *);
> > -static int arm64_switch_stack(struct bt_info *, struct arm64_stackframe *,
> > FILE *);
> >  static int arm64_get_stackframe(struct bt_info *, struct arm64_stackframe
> >  *);
> >  static void arm64_get_stack_frame(struct bt_info *, ulong *, ulong *);
> > +static void arm64_gen_hidden_frame(struct bt_info *bt, ulong, struct
> > arm64_stackframe *);
> >  static void arm64_print_exception_frame(struct bt_info *, ulong, int, FILE
> >  *);
> >  static void arm64_do_bt_reference_check(struct bt_info *, ulong, char *);
> >  static int arm64_translate_pte(ulong, void *, ulonglong);
> > @@ -580,6 +581,10 @@ arm64_dump_machdep_table(ulong arg)
> >     fprintf(fp, "  __exception_text_end: %lx\n", ms->__exception_text_end);
> >     fprintf(fp, " __irqentry_text_start: %lx\n", ms->__irqentry_text_start);
> >     fprintf(fp, "   __irqentry_text_end: %lx\n", ms->__irqentry_text_end);
> > +   fprintf(fp, "      exp_entry1_start: %lx\n", ms->exp_entry1_start);
> > +   fprintf(fp, "        exp_entry1_end: %lx\n", ms->exp_entry1_end);
> > +   fprintf(fp, "      exp_entry2_start: %lx\n", ms->exp_entry2_start);
> > +   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, "         PTE_PROT_NONE: %lx\n", ms->PTE_PROT_NONE);
> >     fprintf(fp, "              PTE_FILE: ");
> > @@ -1286,6 +1291,15 @@ arm64_stackframe_init(void)
> >             machdep->machspec->__irqentry_text_start = sp1->value;
> >             machdep->machspec->__irqentry_text_end = sp2->value;
> >     }
> > +   if ((sp1 = kernel_symbol_search("vectors")) &&
> > +       (sp1n = kernel_symbol_search("cpu_switch_to")) &&
> > +       (sp2 = kernel_symbol_search("ret_fast_syscall")) &&
> > +       (sp2n = kernel_symbol_search("sys_rt_sigreturn_wrapper"))) {
> > +           machdep->machspec->exp_entry1_start = sp1->value;
> > +           machdep->machspec->exp_entry1_end = sp1n->value;
> > +           machdep->machspec->exp_entry2_start = sp2->value;
> > +           machdep->machspec->exp_entry2_end = sp2n->value;
> > +   }
> >  
> >     if ((sp1 = kernel_symbol_search("crash_kexec")) &&
> >         (sp1n = next_symbol(NULL, sp1)) &&
> > @@ -1488,9 +1502,21 @@ arm64_in_exception_text(ulong ptr)
> >     return FALSE;
> >  }
> >  
> > +static int
> > +arm64_in_exp_entry(ulong addr)
> > +{
> > +   struct machine_specific *ms;
> > +
> > +   ms = machdep->machspec;
> > +   if ((ms->exp_entry1_start <= addr) && (addr < ms->exp_entry1_end))
> > +           return TRUE;
> > +   if ((ms->exp_entry2_start <= addr) && (addr < ms->exp_entry2_end))
> > +           return TRUE;
> > +   return FALSE;
> > +}
> > +
> >  #define BACKTRACE_CONTINUE        (1)
> >  #define BACKTRACE_COMPLETE_KERNEL (2)
> > -#define BACKTRACE_COMPLETE_USER   (3)
> >  
> >  static int
> >  arm64_print_stackframe_entry(struct bt_info *bt, int level, struct
> >  arm64_stackframe *frame, FILE *ofp)
> > @@ -1511,11 +1537,6 @@ arm64_print_stackframe_entry(struct bt_info *bt, int
> > level, struct arm64_stackfr
> >                                  value_to_symstr(frame->pc, buf, bt->radix);
> >          }
> >  
> > -   if ((bt->flags & BT_FULL) && level) {
> > -           arm64_display_full_frame(bt, frame->fp);
> > -           bt->frameptr = frame->fp;
> > -   }
> > -
> >          fprintf(ofp, "%s#%d [%8lx] %s at %lx", level < 10 ? " " : "", 
> > level,
> >                  frame->fp ? frame->fp : bt->stacktop - USER_EFRAME_OFFSET,
> >             name_plus_offset ? name_plus_offset : name, frame->pc);
> > @@ -1534,7 +1555,8 @@ arm64_print_stackframe_entry(struct bt_info *bt, int
> > level, struct arm64_stackfr
> >                     fprintf(ofp, "    %s\n", buf);
> >     }
> >  
> > -   if (STREQ(name, "start_kernel") || STREQ(name, 
> > "secondary_start_kernel") ||
> > +   if (STREQ(name, "start_kernel") ||
> > +       STREQ(name, "secondary_start_kernel") ||
> >         STREQ(name, "kthread") || STREQ(name, "kthreadd"))
> >             return BACKTRACE_COMPLETE_KERNEL;
> >  
> > @@ -1542,46 +1564,169 @@ arm64_print_stackframe_entry(struct bt_info *bt, 
> > int
> > level, struct arm64_stackfr
> >  }
> >  
> >  static void
> > -arm64_display_full_frame(struct bt_info *bt, ulong sp)
> > +arm64_display_full_frame(struct bt_info *bt, struct arm64_stackframe *cur,
> > +                                           struct arm64_stackframe *next)
> >  {
> > +   struct machine_specific *ms;
> > +   ulong next_fp, stackbase;
> > +   char *stackbuf;
> >     int i, u_idx;
> >     ulong *up;
> >     ulong words, addr;
> >     char buf[BUFSIZE];
> >  
> > -   if (bt->frameptr == sp)
> > -           return;
> > +   stackbase = bt->stackbase;
> > +   stackbuf = bt->stackbuf;
> > +   ms = machdep->machspec;
> >  
> > -   if (!INSTACK(sp, bt) || !INSTACK(bt->frameptr, bt)) {
> > -           if (sp == 0)
> > -                   sp = bt->stacktop - USER_EFRAME_OFFSET;
> > -           else
> > -                   return;
> > -   }
> > +   /* Calc next fp for dump */
> > +   if (next->fp == 0)
> > +           /* last stackframe on kernel tack */
> > +           next_fp = bt->stacktop - 0x10;
> > +   else if (!INSTACK(cur->sp, bt)) {
> > +           /* We have just switched over stacks */
> > +           next_fp = ms->irq_stacks[bt->tc->processor]
> > +                           + ms->irq_stack_size - 0x10;
> > +
> > +           /*
> > +            * We are already buffering a process stack.
> > +            * So use an old buffer for IRQ stack.
> > +            */
> > +           stackbase = ms->irq_stacks[bt->tc->processor];
> > +           stackbuf = ms->irq_stackbuf;
> > +   } else
> > +           next_fp = next->fp;
> > +
> > +   if (CRASHDEBUG(1))
> > +           fprintf(fp, "    frame <%016lx:%016lx>\n", cur->fp, next_fp);
> >  
> > -   words = (sp - bt->frameptr) / sizeof(ulong);
> > +   /* Check here because we want to see a debug message above. */
> > +   if (!(bt->flags & BT_FULL))
> > +           return;
> >  
> > -   addr = bt->frameptr;
> > -   u_idx = (bt->frameptr - bt->stackbase)/sizeof(ulong);
> > +   /* Dump */
> > +   words = (next_fp - cur->fp) / sizeof(ulong);
> > +   addr = cur->fp;
> > +   u_idx = (cur->fp - stackbase)/sizeof(ulong);
> >     for (i = 0; i < words; i++, u_idx++) {
> >             if (!(i & 1))
> >                     fprintf(fp, "%s    %lx: ", i ? "\n" : "", addr);
> >  
> > -           up = (ulong *)(&bt->stackbuf[u_idx*sizeof(ulong)]);
> > +           up = (ulong *)(&stackbuf[u_idx*sizeof(ulong)]);
> >             fprintf(fp, "%s ", format_stack_entry(bt, buf, *up, 0));
> >  
> >             addr += sizeof(ulong);
> >     }
> >     fprintf(fp, "\n");
> > +
> > +   if (stackbuf == ms->irq_stackbuf)
> > +           FREEBUF(stackbuf);
> >  }
> >  
> > -static int
> > -arm64_unwind_frame(struct bt_info *bt, struct arm64_stackframe *frame)
> > +/*
> > + * (1)Normal frame:
> > + *     +------+
> > + *     | pfp  |
> > + *     | cpc  |
> > + * psp +      +
> > + *     |      |
> > + *     |      |
> > + * pfp +------+ <--- :prev stackframe = <pfp, psp, ppc>
> > + *     | cfp  |
> > + *     | npc  |
> > + * csp +      +
> > + *     |      |
> > + *     |      |
> > + * cfp +------+ <--- :curr stackframe = <cfp, csp, cpc>
> > + *     | nfp  |   |                         cfp = *pfp
> > + *     | Npc  |   |                         csp = pfp + 0x10
> > + * nsp +      +  real stackframe
> > + *     |      |   |         at cpc
> > + *     |      |   |
> > + * nfp +------+ <--- :next stackframe = <nfp, nsp, npc>
> > + *     |      |
> > + *
> > + * (2)Exception:
> > + *     +------+
> > + *     | pfp  |
> > + *     | cpc  |
> > + * psp +      +
> > + *     |      |
> > + *     |      |
> > + * pfp +------+ <--- :prev stackframe = <pfp, psp, ppc>
> > + *     | cfp  |
> > + *     | npc  |
> > + * csp +      +
> > + *     |      |
> > + *     |      |
> > + * cfp +------+ <--- :stackframe = <cfp, csp, cpc>
> > + *     | nfp  |
> > + *     | epc  |
> > + *     +      +
> > + *     |      |
> > + *     |      |       calced dummy
> > + * esp +------+ <--- :exp stackframe = <---, esp, epc>
> > + *     |      |                           esp = nsp - sizeof(pt_regs)
> > + *     |      |
> > + *     | Npc  |
> > + *     | nfp  |
> > + *     | nsp  |
> > + *     | npc  |
> > + * nsp +      +
> > + *     |      |       calced missing
> > + * nfp +------+ <--- :task stackframe = <nfp, nsp, npc>
> > + *     | Nfp  |
> > + *     | NNpc |
> > + * Nsp +      +
> > + *     |      |
> > + * Nfp +------+ <--- :task stackframe = <Nfp, Nsp, Npc>
> > + *     | NNfp |
> > + *
> > + * (3)At interrupt:
> > + *     +------+
> > + *     | pfp  |
> > + *     | cpc  |
> > + * psp +      +
> > + *     |      |
> > + *     |      |
> > + * pfp +------+ <--- :prev stackframe = <pfp, psp, ppc>
> > + *     | cfp  |
> > + *     | epc  |
> > + * csp +      +
> > + *     |      |
> > + *     |      |       calced dummy
> > + * cfp +------+ <--- :irq stackframe = <cfp, csp, epc>
> > + *     | nfp  |                          | if (cfp == IRQ_STACK_PTR)
> > + *     | esp  |                          V
> > + * top +------+                        <---, esp, epc>
> > + *     IRQ stack
> > + *
> > + *                    calced dummy
> > + * esp +------+ <--- :exp stackframe = <---, esp, epc>
> > + *     |      |                            esp = nsp - sizeof(pt_regs)
> > + *     |      |
> > + *     | Npc  |
> > + *     | nfp  |
> > + *     | nsp  |
> > + *     | npc  |       calced missing
> > + * nfp +------+ <--- :task stackframe = <nfp, nsp, npc>
> > + *     | Nfp  |
> > + *     | NNpc |
> > + * Nsp +      +
> > + *     |      |
> > + * Nfp +------+ <--- :task stackframe = <Nfp, Nsp, Npc>
> > + *     | NNfp |
> > + */
> > +
> > +static struct arm64_stackframe ext_frame;
> > +
> > +static int
> > +arm64_unwind_frame(struct bt_info *bt, struct arm64_stackframe *frame,
> > +                                                           FILE *ofp)
> >  {
> >     unsigned long high, low, fp;
> >     unsigned long stack_mask;
> >     unsigned long irq_stack_ptr, orig_sp;
> > -   struct arm64_pt_regs *ptregs;
> >     struct machine_specific *ms;
> >  
> >     stack_mask = (unsigned long)(ARM64_STACK_SIZE) - 1;
> > @@ -1593,54 +1738,101 @@ arm64_unwind_frame(struct bt_info *bt, struct
> > arm64_stackframe *frame)
> >     if (fp < low || fp > high || fp & 0xf)
> >             return FALSE;
> >  
> > -   frame->sp = fp + 0x10;
> > -   frame->fp = GET_STACK_ULONG(fp);
> > +   if (CRASHDEBUG(1))
> > +           fprintf(ofp, "    cur fp:%016lx sp:%016lx pc:%016lx\n",
> > +                                   frame->fp, frame->sp, frame->pc);
> > +
> > +   if (ext_frame.pc) {
> > +           /*
> > +            * Previous frame was a dummy for exception entry.
> > +            * So insert a hidden (real) stackframe.
> > +           */
> > +           frame->fp = ext_frame.fp;
> > +           frame->sp = ext_frame.sp;
> > +           frame->pc = ext_frame.pc;
> > +
> > +           ext_frame.pc = 0; /* back to normal unwinding */
> > +
> > +           goto unwind_done;
> > +   }
> > +
> >     frame->pc = GET_STACK_ULONG(fp + 8);
> > +   if (!arm64_in_exp_entry(frame->pc)) {
> > +           /* Normal stack frame */
> >  
> > -   /*
> > -    * 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) {
> > -           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);
> > +           frame->sp = fp + 0x10;
> > +           frame->fp = GET_STACK_ULONG(fp);
> > +   } else {
> > +           /*
> > +            * We are in exception entry code, and so need to
> > +            *   - fake a dummy frame for exception frame, and
> > +            *   - complement a stackframe hidden by exception
> > +            */
> > +
> > +           ext_frame.fp = GET_STACK_ULONG(fp);
> > +           if (ext_frame.fp == 0) {
> > +                   /*
> > +                    * Either on process stack or on IRQ stack,
> > +                    * the next frame is the last one on process stack.
> > +                    */
> > +
> > +                   frame->sp = bt->stacktop
> > +                               - sizeof(struct arm64_pt_regs) - 0x10;
> > +                   frame->fp = frame->sp;
> > +           } else if (!machdep->flags & IRQ_STACKS) {
> > +                   /*
> > +                    * We are on process stack. Just fake a dummy frame
> > +                    */
> > +
> > +                   frame->sp = ext_frame.fp
> > +                               - sizeof(struct arm64_pt_regs);
> > +                   frame->fp = frame->sp;
> > +           } else {
> > +                   /* We are on IRQ stack */
> > +
> > +                   ms = machdep->machspec;
> > +                   irq_stack_ptr = ms->irq_stacks[bt->tc->processor]
> > +                                           + ms->irq_stack_size - 0x20;
> > +                   if (ext_frame.fp != irq_stack_ptr) {
> > +                           /* Just fake a dummy frame */
> > +
> > +                           frame->sp = ext_frame.fp
> > +                                       - sizeof(struct arm64_pt_regs);
> > +                           frame->fp = frame->sp;
> >                     } 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;
> > +                           /*
> > +                            * switch from IRQ stack to process stack
> > +                            */
> > +
> > +                           frame->sp = GET_STACK_ULONG(irq_stack_ptr + 8);
> > +                           frame->fp = frame->sp;
> > +
> > +                           /*
> > +                            * Keep a buffer for a while until
> > +                            * displaying the last frame on IRQ stack.
> > +                            * Ugly?
> > +                            */
> > +                           if (bt->flags | BT_FULL)
> > +                                   ms->irq_stackbuf = bt->stackbuf;
> > +
> > +                           arm64_set_process_stack(bt);
> >                     }
> >             }
> > +
> > +           arm64_gen_hidden_frame(bt, frame->sp, &ext_frame);
> >     }
> >  
> > +unwind_done:
> > +   if (CRASHDEBUG(1))
> > +           fprintf(ofp, "    nxt fp:%016lx sp:%016lx pc:%016lx\n",
> > +                                   frame->fp, frame->sp, frame->pc);
> > +
> >     return TRUE;
> >  }
> >  
> > -/*
> > +/*
> >   *  A layout of a stack frame in a function looks like:
> > - *
> > + *
> >   *           stack grows to lower addresses.
> >   *             /|\
> >   *              |
> > @@ -1658,7 +1850,7 @@ arm64_unwind_frame(struct bt_info *bt, struct
> > arm64_stackframe *frame)
> >   *           | vars |
> >   *  old fp   +------+
> >   *           |      |
> > - *
> > + *
> >   *  - On function entry, sp is decremented down to new fp.
> >   *
> >   *  - and old fp and sp are saved into this stack frame.
> > @@ -1680,13 +1872,13 @@ arm64_unwind_frame(struct bt_info *bt, struct
> > arm64_stackframe *frame)
> >   *    sp shows "callee's static local variables", old fp and sp.
> >   *
> >   *  Diagram and explanation courtesy of Takahiro Akashi
> > - */
> > + */
> >  
> >  static void
> >  arm64_back_trace_cmd(struct bt_info *bt)
> >  {
> > -   struct arm64_stackframe stackframe;
> > -   int level;
> > +   struct arm64_stackframe stackframe, cur_frame;
> > +   int level, mode;
> >     ulong exception_frame;
> >     FILE *ofp;
> >  
> > @@ -1708,17 +1900,7 @@ arm64_back_trace_cmd(struct bt_info *bt)
> >             stackframe.fp = GET_STACK_ULONG(bt->bptr - 8);
> >             stackframe.pc = GET_STACK_ULONG(bt->bptr);
> >             stackframe.sp = bt->bptr + 8;
> > -           bt->frameptr = stackframe.sp;
> > -   } else if (bt->hp && bt->hp->esp) {
> > -           if (arm64_on_irq_stack(bt->tc->processor, bt->hp->esp)) {
> > -                   arm64_set_irq_stack(bt);
> > -                   bt->flags |= BT_IRQSTACK;
> > -           }
> > -           stackframe.fp = GET_STACK_ULONG(bt->hp->esp - 8);
> > -           stackframe.pc = bt->hp->eip ?
> > -                   bt->hp->eip : GET_STACK_ULONG(bt->hp->esp);
> > -           stackframe.sp = bt->hp->esp + 8;
> > -           bt->flags &= ~BT_REGS_NOT_FOUND;
> > +           bt->frameptr = stackframe.fp;
> >     } else {
> >             stackframe.sp = bt->stkptr;
> >             stackframe.pc = bt->instptr;
> > @@ -1739,8 +1921,14 @@ arm64_back_trace_cmd(struct bt_info *bt)
> >             return;
> >  
> >     if (!(bt->flags & BT_KDUMP_ADJUST)) {
> > -           if (bt->flags & BT_USER_SPACE)
> > -                   goto complete_user;
> > +           if (bt->flags & BT_USER_SPACE) {
> > +                   exception_frame = bt->stacktop - USER_EFRAME_OFFSET;
> > +                   arm64_print_exception_frame(bt, exception_frame,
> > +                                                   USER_MODE, ofp);
> > +                   fprintf(ofp, " #0 [user space]\n");
> > +
> > +                   return;
> > +           }
> >  
> >             if (DUMPFILE() && is_task_active(bt->task)) {
> >                     exception_frame = stackframe.fp - SIZE(pt_regs);
> > @@ -1750,53 +1938,55 @@ arm64_back_trace_cmd(struct bt_info *bt)
> >             }
> >     }
> >  
> > -   level = exception_frame = 0;
> > -   while (1) {
> > +   for (level = 0;; level++) {
> >             bt->instptr = stackframe.pc;
> >  
> > -           switch (arm64_print_stackframe_entry(bt, level, &stackframe, 
> > ofp))
> > -           {
> > -           case BACKTRACE_COMPLETE_KERNEL:
> > -                   return;
> > -           case BACKTRACE_COMPLETE_USER:
> > -                   goto complete_user;
> > -           case BACKTRACE_CONTINUE:
> > +           /*
> > +            * Show one-line stackframe info
> > +            */
> > +           if (arm64_print_stackframe_entry(bt, level, &stackframe, ofp)
> > +               == BACKTRACE_COMPLETE_KERNEL)
> >                     break;
> > -           }
> > -
> > -           if (exception_frame) {
> > -                   arm64_print_exception_frame(bt, exception_frame, 
> > KERNEL_MODE, ofp);
> > -                   exception_frame = 0;
> > -           }
> >  
> > -           if (!arm64_unwind_frame(bt, &stackframe))
> > +           cur_frame = stackframe;
> > +           if (!arm64_unwind_frame(bt, &stackframe, ofp))
> >                     break;
> >  
> > -           if (arm64_in_exception_text(bt->instptr) && 
> > INSTACK(stackframe.fp, bt)) {
> > -                   if (!(bt->flags & BT_IRQSTACK) ||
> > -                       (((stackframe.sp + SIZE(pt_regs)) < bt->stacktop)))
> > -                           exception_frame = stackframe.fp - SIZE(pt_regs);
> > -           }
> > +           /*
> > +            * Dump the contents of the current stackframe.
> > +            * We need to know the next stackframe to determine
> > +            * the dump range:
> > +            *    <cur_frame.fp:stackframe.fp>
> > +            */
> > +           arm64_display_full_frame(bt, &cur_frame, &stackframe);
> >  
> > -           if ((bt->flags & BT_IRQSTACK) &&
> > -               !arm64_on_irq_stack(bt->tc->processor, stackframe.sp)) {
> > -                   bt->flags &= ~BT_IRQSTACK;
> > -                   if (arm64_switch_stack(bt, &stackframe, ofp) == 
> > USER_MODE)
> > -                           break;
> > -           }
> > +           /*
> > +            * If we are in a normal stackframe, just continue,
> > +            * otherwise show an exception frame.
> > +            * Since exception entry code doesn't have a real
> > +            * stackframe, we fake a dummy frame here.
> > +            */
> > +           if (!arm64_in_exp_entry(stackframe.pc))
> > +                   continue;
> >  
> > +           if (!INSTACK(cur_frame.sp, bt))
> > +                   fprintf(ofp, "--- <IRQ stack> ---\n");
> >  
> > -           level++;
> > -   }
> > +           arm64_print_stackframe_entry(bt, ++level, &stackframe, ofp);
> > +           cur_frame = stackframe;
> > +           arm64_unwind_frame(bt, &stackframe, ofp);
> >  
> > -   if (is_kernel_thread(bt->tc->task))
> > -           return;
> > +           /*
> > +            * and don't show the contenxts. Instead,
> > +            * show an exception frame below
> > +            */
> > +           mode = (stackframe.pc < machdep->machspec->userspace_top) ?
> > +                           USER_MODE : KERNEL_MODE;
> > +           arm64_print_exception_frame(bt, cur_frame.sp, mode, ofp);
> >  
> > -complete_user:
> > -   exception_frame = bt->stacktop - USER_EFRAME_OFFSET;
> > -   arm64_print_exception_frame(bt, exception_frame, USER_MODE, ofp);
> > -   if ((bt->flags & (BT_USER_SPACE|BT_KDUMP_ADJUST)) == BT_USER_SPACE)
> > -           fprintf(ofp, " #0 [user space]\n");
> > +           if (mode == USER_MODE)
> > +                   break;
> > +   }
> >  }
> >  
> >  static void
> > @@ -1932,41 +2122,6 @@ arm64_in_kdump_text_on_irq_stack(struct bt_info *bt)
> >     return FALSE;
> >  }
> >  
> > -static int
> > -arm64_switch_stack(struct bt_info *bt, struct arm64_stackframe *frame, FILE
> > *ofp)
> > -{
> > -   int i;
> > -   ulong stacktop, words, addr;
> > -   ulong *stackbuf;
> > -   char buf[BUFSIZE];
> > -   struct machine_specific *ms = machdep->machspec;
> > -
> > -   if (bt->flags & BT_FULL) {
> > -           stacktop = ms->irq_stacks[bt->tc->processor] + 
> > ms->irq_stack_size;
> > -           words = (stacktop - bt->bptr) / sizeof(ulong);
> > -           stackbuf = (ulong *)GETBUF(words * sizeof(ulong));
> > -           readmem(bt->bptr, KVADDR, stackbuf, words * sizeof(long),
> > -                   "top of IRQ stack", FAULT_ON_ERROR);
> > -
> > -           addr = bt->bptr;
> > -           for (i = 0; i < words; i++) {
> > -                   if (!(i & 1))
> > -                           fprintf(ofp, "%s    %lx: ", i ? "\n" : "", 
> > addr);
> > -                   fprintf(ofp, "%s ", format_stack_entry(bt, buf, 
> > stackbuf[i], 0));
> > -                   addr += sizeof(ulong);
> > -           }
> > -           fprintf(ofp, "\n");
> > -           FREEBUF(stackbuf);
> > -   }
> > -   fprintf(ofp, "--- <IRQ stack> ---\n");
> > -
> > -   if (frame->fp == 0)
> > -           return USER_MODE;
> > -
> > -   arm64_print_exception_frame(bt, frame->sp, KERNEL_MODE, ofp);
> > -   return KERNEL_MODE;
> > -}
> > -
> >  static int
> >  arm64_get_dumpfile_stackframe(struct bt_info *bt, struct arm64_stackframe
> >  *frame)
> >  {
> > @@ -2047,6 +2202,20 @@ arm64_get_stack_frame(struct bt_info *bt, ulong *pcp,
> > ulong *spp)
> >  }
> >  
> >  static void
> > +arm64_gen_hidden_frame(struct bt_info *bt, ulong sp,
> > +                                   struct arm64_stackframe *frame)
> > +{
> > +   struct arm64_pt_regs *ptregs;
> > +
> > +   ptregs = (struct arm64_pt_regs *)
> > +            &bt->stackbuf[(ulong)(STACK_OFFSET_TYPE(sp))];
> > +
> > +   frame->pc = ptregs->pc;
> > +   frame->fp = ptregs->regs[29];
> > +   frame->sp = ptregs->sp;
> > +}
> > +
> > +static void
> >  arm64_print_exception_frame(struct bt_info *bt, ulong pt_regs, int mode,
> >  FILE *ofp)
> >  {
> >     int i, r, rows, top_reg, is_64_bit;
> > @@ -2055,10 +2224,16 @@ arm64_print_exception_frame(struct bt_info *bt, 
> > ulong
> > pt_regs, int mode, FILE *o
> >     ulong LR, SP, offset;
> >     char buf[BUFSIZE];
> >  
> > +   if (mode == KERNEL_MODE)
> > +           fprintf(ofp, "--- <Exception in kernel> ---\n");
> > +   else
> > +           fprintf(ofp, "--- <Exception in user> ---\n");
> > +
> >     if (CRASHDEBUG(1))
> >             fprintf(ofp, "pt_regs: %lx\n", pt_regs);
> >  
> > -   regs = (struct arm64_pt_regs
> > *)&bt->stackbuf[(ulong)(STACK_OFFSET_TYPE(pt_regs))];
> > +   regs = (struct arm64_pt_regs *)
> > +          &bt->stackbuf[(ulong)(STACK_OFFSET_TYPE(pt_regs))];
> >  
> >     if ((mode == USER_MODE) && (regs->pstate & PSR_MODE32_BIT)) {
> >             LR = regs->regs[14];
> > @@ -2130,10 +2305,11 @@ arm64_print_exception_frame(struct bt_info *bt, 
> > ulong
> > pt_regs, int mode, FILE *o
> >     }
> >  
> >     if (is_64_bit) {
> > -           fprintf(ofp, "ORIG_X0: %016lx  SYSCALLNO: %lx",
> > -                   (ulong)regs->orig_x0, (ulong)regs->syscallno);
> > -           if (mode == USER_MODE)
> > +           if (mode == USER_MODE) {
> > +                   fprintf(ofp, "ORIG_X0: %016lx  SYSCALLNO: %lx",
> > +                           (ulong)regs->orig_x0, (ulong)regs->syscallno);
> >                     fprintf(ofp, "  PSTATE: %08lx", (ulong)regs->pstate);
> > +           }
> >             fprintf(ofp, "\n");
> >     }
> >  
> > diff --git a/defs.h b/defs.h
> > index d6f719c..f7ea5a0 100644
> > --- a/defs.h
> > +++ b/defs.h
> > @@ -3058,8 +3058,14 @@ struct machine_specific {
> >     ulong kernel_flags;
> >     ulong irq_stack_size;
> >     ulong *irq_stacks;
> > +   char  *irq_stackbuf;
> >     ulong __irqentry_text_start;
> >     ulong __irqentry_text_end;
> > +   /* for exception vector code */
> > +   ulong exp_entry1_start;
> > +   ulong exp_entry1_end;
> > +   ulong exp_entry2_start;
> > +   ulong exp_entry2_end;
> >     /* only needed for v4.6 or later kernel */
> >     ulong kimage_voffset;
> >     ulong kimage_text;
> > --
> > 2.9.0
> > 
> > --
> > Crash-utility mailing list
> > [email protected]
> > https://www.redhat.com/mailman/listinfo/crash-utility
> > 
> 
> --
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