Re: "Can't analyze prologue code ..." at boot time

[Atsushi Nemoto <anemo@mba.ocn.ne.jp>]

>>>>> On Fri, 29 Oct 2004 00:07:57 +0900 (JST), Atsushi Nemoto 
>>>>> <anemo@mba.ocn.ne.jp> said:
anemo> Here is a revised patch which can work with gcc 3.4.

anemo> Ralf, how about this patch?  No more maintenance nightmare :-)

I found that still "Can't analyze" message displayed with gcc 3.4.
Revised again.

diff -u linux-mips-cvs/arch/mips/kernel/process.c 
linux-mips/arch/mips/kernel/process.c
--- linux-mips-cvs/arch/mips/kernel/process.c   Fri Oct 29 20:14:01 2004
+++ linux-mips/arch/mips/kernel/process.c       Fri Oct 29 20:13:18 2004
@@ -185,22 +185,49 @@
        return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL, 
NULL);
 }
 
-struct mips_frame_info {
+static struct mips_frame_info {
+       void *func;
+       int omit_fp;    /* compiled without fno-omit-frame-pointer */
        int frame_offset;
        int pc_offset;
+} schedule_frame, mfinfo[] = {
+       { schedule, 0 },        /* must be first */
+       /* arch/mips/kernel/semaphore.c */
+       { __down, 1 },
+       { __down_interruptible, 1 },
+       /* kernel/sched.c */
+#ifdef CONFIG_PREEMPT
+       { preempt_schedule, 0 },
+#endif
+       { wait_for_completion, 0 },
+       { interruptible_sleep_on, 0 },
+       { interruptible_sleep_on_timeout, 0 },
+       { sleep_on, 0 },
+       { sleep_on_timeout, 0 },
+       { __cond_resched, 0 },
+       { yield, 0 },
+       { io_schedule, 0 },
+       { io_schedule_timeout, 0 },
+#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT)
+       { __preempt_spin_lock, 0 },
+       { __preempt_write_lock, 0 },
+#endif
+       /* kernel/timer.c */
+       { schedule_timeout, 1 },
+/*     { nanosleep_restart, 1 }, */
+       /* lib/rwsem-spinlock.c */
+       { __down_read, 1 },
+       { __down_write, 1 },
 };
-static struct mips_frame_info schedule_frame;
-static struct mips_frame_info schedule_timeout_frame;
-static struct mips_frame_info sleep_on_frame;
-static struct mips_frame_info sleep_on_timeout_frame;
-static struct mips_frame_info wait_for_completion_frame;
+
 static int mips_frame_info_initialized;
-static int __init get_frame_info(struct mips_frame_info *info, void *func)
+static int __init get_frame_info(struct mips_frame_info *info)
 {
        int i;
+       void *func = info->func;
        union mips_instruction *ip = (union mips_instruction *)func;
        info->pc_offset = -1;
-       info->frame_offset = -1;
+       info->frame_offset = info->omit_fp ? 0 : -1;
        for (i = 0; i < 128; i++, ip++) {
                /* if jal, jalr, jr, stop. */
                if (ip->j_format.opcode == jal_op ||
@@ -227,8 +254,10 @@
                        }
                        /* sw / sd $s8, offset($sp) */
                        if (ip->i_format.rt == 30) {
+#if 0  /* gcc 3.4 does aggressive optimization... */
                                if (info->frame_offset != -1)
                                        break;
+#endif
                                info->frame_offset =
                                        ip->i_format.simmediate / sizeof(long);
                        }
@@ -246,13 +275,25 @@
 
 static int __init frame_info_init(void)
 {
-       mips_frame_info_initialized =
-               !get_frame_info(&schedule_frame, schedule) &&
-               !get_frame_info(&schedule_timeout_frame, schedule_timeout) &&
-               !get_frame_info(&sleep_on_frame, sleep_on) &&
-               !get_frame_info(&sleep_on_timeout_frame, sleep_on_timeout) &&
-               !get_frame_info(&wait_for_completion_frame, 
wait_for_completion);
-
+       int i, found;
+       for (i = 0; i < ARRAY_SIZE(mfinfo); i++)
+               if (get_frame_info(&mfinfo[i]))
+                       return -1;
+       schedule_frame = mfinfo[0];
+       /* bubble sort */
+       do {
+               struct mips_frame_info tmp;
+               found = 0;
+               for (i = 1; i < ARRAY_SIZE(mfinfo); i++) {
+                       if (mfinfo[i-1].func > mfinfo[i].func) {
+                               tmp = mfinfo[i];
+                               mfinfo[i] = mfinfo[i-1];
+                               mfinfo[i-1] = tmp;
+                               found = 1;
+                       }
+               }
+       } while (found);
+       mips_frame_info_initialized = 1;
        return 0;
 }
 
@@ -286,45 +327,25 @@
        if (!mips_frame_info_initialized)
                return 0;
        pc = thread_saved_pc(p);
+
        if (!in_sched_functions(pc))
                goto out;
 
-       if (pc >= (unsigned long) sleep_on_timeout)
-               goto schedule_timeout_caller;
-       if (pc >= (unsigned long) sleep_on)
-               goto schedule_caller;
-       if (pc >= (unsigned long) interruptible_sleep_on_timeout)
-               goto schedule_timeout_caller;
-       if (pc >= (unsigned long)interruptible_sleep_on)
-               goto schedule_caller;
-       if (pc >= (unsigned long)wait_for_completion)
-               goto schedule_caller;
-       goto schedule_timeout_caller;
-
-schedule_caller:
-       frame = ((unsigned long *)p->thread.reg30)[schedule_frame.frame_offset];
-       if (pc >= (unsigned long) sleep_on)
-               pc = ((unsigned long *)frame)[sleep_on_frame.pc_offset];
-       else
-               pc = ((unsigned long 
*)frame)[wait_for_completion_frame.pc_offset];
-       goto out;
-
-schedule_timeout_caller:
-       /*
-        * The schedule_timeout frame
-        */
        frame = ((unsigned long *)p->thread.reg30)[schedule_frame.frame_offset];
+       do {
+               int i;
+               for (i = ARRAY_SIZE(mfinfo) - 1; i >= 0; i--) {
+                       if (pc >= (unsigned long) mfinfo[i].func)
+                               break;
+               }
+               if (i < 0)
+                       break;
 
-       /*
-        * frame now points to sleep_on_timeout's frame
-        */
-       pc    = ((unsigned long *)frame)[schedule_timeout_frame.pc_offset];
-
-       if (in_sched_functions(pc)) {
-               /* schedule_timeout called by [interruptible_]sleep_on_timeout 
*/
-               frame = ((unsigned long 
*)frame)[schedule_timeout_frame.frame_offset];
-               pc    = ((unsigned long 
*)frame)[sleep_on_timeout_frame.pc_offset];
-       }
+               if (mfinfo[i].omit_fp)
+                       break;
+               pc = ((unsigned long *)frame)[mfinfo[i].pc_offset];
+               frame = ((unsigned long *)frame)[mfinfo[i].frame_offset];
+       } while (in_sched_functions(pc));
 
 out:
 

---
Atsushi Nemoto