[Linux-ia64] Debugging early ode under the simulator

[Linux-ia64] Debugging early ode under the simulator

[Peter Chubb]

Hi,
	There's no easy way to set breakpoints or watchpoints in the
kernel before the kernel starts running, when running under the SKI
simulator.

One way to fix this is appended.

# This is a BitKeeper generated patch for the following project:
# Project Name: Linux kernel tree
# This patch format is intended for GNU patch command version 2.5 or higher.
# This patch includes the following deltas:
#	           ChangeSet	1.814   -> 1.815  
#	arch/ia64/boot/bootloader.c	1.3     -> 1.4    
#
# The following is the BitKeeper ChangeSet Log
# --------------------------------------------
# 02/11/14	peterc@gelato.unsw.edu.au	1.815
# Add a debug breakpoint dummy function.
# 
# When in the simulator, one cannot set a break point or watchpoint 
# before the symbol table for the kernel is in memory, 
# and the kernel has set things up to run in a virtual addrs space.
# 
# Therefore, insert a dummy function here that one can set a breakpoint
# on, then single step a  few dozen times, then set up the 
# breakpoints one really wants.
# --------------------------------------------
#
diff -Nru a/arch/ia64/boot/bootloader.c b/arch/ia64/boot/bootloader.c
--- a/arch/ia64/boot/bootloader.c	Thu Nov 14 15:36:29 2002
+++ b/arch/ia64/boot/bootloader.c	Thu Nov 14 15:36:29 2002
@@ -53,6 +53,14 @@
 
 #include "../kernel/fw-emu.c"
 
+/*
+ * Set a break point on this function so that
+ * symbols are available to set breakpoints in the 
+ * kernel being debugged.
+ */
+void debug_break(void) {
+}
+
 static void
 cons_write (const char *buf)
 {
@@ -187,6 +195,7 @@
 
 	ssc(0, (long) kpath, 0, 0, SSC_LOAD_SYMBOLS);
 
+	debug_break();
 	asm volatile ("mov sp=%2; mov r28=%1; br.sptk.few %0"
 		      :: "b"(e_entry), "r"(bp), "r"(__pa(&stack)));
 


--
Dr Peter Chubb				    peterc@gelato.unsw.edu.au
You are lost in a maze of BitKeeper repositories, all almost the same.

Re: [Linux-ia64] Debugging early ode under the simulator

[David Mosberger]

>>>>> On Thu, 14 Nov 2002 15:41:38 +1100, Peter Chubb <peter@chubb.wattle.id.au> said:

  Peter> Hi, There's no easy way to set breakpoints or watchpoints in
  Peter> the kernel before the kernel starts running, when running
  Peter> under the SKI simulator.

  Peter> One way to fix this is appended.

I usually would just look for the indirect branch in _start(), but
that's admittedly not the most obvious way to go about it.  Your
solution is easier for new users, so I applied a (slightly modified)
version of it.

Thanks,

	--david