Re: PPC KGDB changes and some help?

[Tom Rini <trini@kernel.crashing.org>]

On Thu, Jan 22, 2004 at 11:05:55AM -0700, Tom Rini wrote:
[snip]
> First up:
> We need to call flush_instruction_cache() on a 'c' or 's' command.
>  arch/ppc/kernel/ppc-stub.c |   19 ++++++-------------
>  1 files changed, 6 insertions(+), 13 deletions(-)

On tpo of this patch, there's the following:
Put back some code to figure out what signal we're dealing with.

 arch/ppc/kernel/ppc-stub.c |   63 ++++++++++++++++++++++++++++++++++++++++++---
 1 files changed, 60 insertions(+), 3 deletions(-)
--- 1.15/arch/ppc/kernel/ppc-stub.c	Thu Jan 22 10:53:06 2004
+++ edited/arch/ppc/kernel/ppc-stub.c	Fri Jan 23 15:43:10 2004
@@ -3,6 +3,7 @@
  *
  * PowerPC-specific bits to work with the common KGDB stub.
  *
+ * 1998 (c) Michael AK Tesch (tesch@cs.wisc.edu)
  * 2003 (c) TimeSys Corporation
  * 2004 (c) MontaVista Software, Inc.
  * This file is licensed under the terms of the GNU General Public License
@@ -19,13 +20,69 @@
 #include <asm/processor.h>
 #include <asm/machdep.h>
 
+/* Convert the hardware trap type code to a unix signal number. */
+/*
+ * This table contains the mapping between PowerPC hardware trap types, and
+ * signals, which are primarily what GDB understands.
+ */
+static struct hard_trap_info
+{
+	unsigned int tt;		/* Trap type code for powerpc */
+	unsigned char signo;		/* Signal that we map this trap into */
+} hard_trap_info[] = {
+#if defined(CONFIG_40x)
+	{ 0x100, SIGINT  },		/* critical input interrupt */
+	{ 0x200, SIGSEGV },		/* machine check */
+	{ 0x300, SIGSEGV },		/* data storage */
+	{ 0x400, SIGBUS  },		/* instruction storage */
+	{ 0x500, SIGINT  },		/* interrupt */
+	{ 0x600, SIGBUS  },		/* alignment */
+	{ 0x700, SIGILL  },		/* program */
+	{ 0x800, SIGILL  },		/* reserved */
+	{ 0x900, SIGILL  },		/* reserved */
+	{ 0xa00, SIGILL  },		/* reserved */
+	{ 0xb00, SIGILL  },		/* reserved */
+	{ 0xc00, SIGCHLD },		/* syscall */
+	{ 0xd00, SIGILL  },		/* reserved */
+	{ 0xe00, SIGILL  },		/* reserved */
+	{ 0xf00, SIGILL  },		/* reserved */
+	{ 0x2000, SIGTRAP},		/* debug */
+#else
+	{ 0x200, SIGSEGV },		/* machine check */
+	{ 0x300, SIGSEGV },		/* address error (store) */
+	{ 0x400, SIGBUS },		/* instruction bus error */
+	{ 0x500, SIGINT },		/* interrupt */
+	{ 0x600, SIGBUS },		/* alingment */
+	{ 0x700, SIGTRAP },		/* breakpoint trap */
+	{ 0x800, SIGFPE },		/* fpu unavail */
+	{ 0x900, SIGALRM },		/* decrementer */
+	{ 0xa00, SIGILL },		/* reserved */
+	{ 0xb00, SIGILL },		/* reserved */
+	{ 0xc00, SIGCHLD },		/* syscall */
+	{ 0xd00, SIGTRAP },		/* single-step/watch */
+	{ 0xe00, SIGFPE },		/* fp assist */
+#endif
+	{ 0, 0}				/* Must be last */
+};
+
+static int computeSignal(unsigned int tt)
+{
+	struct hard_trap_info *ht;
+
+	for (ht = hard_trap_info; ht->tt && ht->signo; ht++)
+		if (ht->tt == tt)
+			return ht->signo;
+
+	return SIGHUP; /* default for things we don't know about */
+}
+
 /*
  * Routines
  */
 static void
 kgdb_debugger(struct pt_regs *regs)
 {
-	(*linux_debug_hook) (0, 0, 0, regs);
+	(*linux_debug_hook) (0, computeSignal(regs->trap), 0, regs);
 	return;
 }
 
@@ -52,14 +109,14 @@
 int
 kgdb_iabr_match(struct pt_regs *regs)
 {
-	(*linux_debug_hook) (0, 0, 0, regs);
+	(*linux_debug_hook) (0, computeSignal(regs->trap), 0, regs);
 	return 1;
 }
 
 int
 kgdb_dabr_match(struct pt_regs *regs)
 {
-	(*linux_debug_hook) (0, 0, 0, regs);
+	(*linux_debug_hook) (0, computeSignal(regs->trap), 0, regs);
 	return 1;
 }
 

Now, not being as well versed in all of the debugging infos that can be
passed around, it sounds like this patch could be dropped in the future
for a cleaner method using some of the dwarf2 bits being talked about.
But I don't know, and clarification and pointers (if so) to how to do
this would be appreciated.

-- 
Tom Rini
http://gate.crashing.org/~trini/