From 4a761caec7754f1fc2754466099320c54bf45abb Mon Sep 17 00:00:00 2001
From: jeff <jeff@FreeBSD.org>
Date: Wed, 3 Aug 2005 04:27:40 +0000
Subject:  - Add support for saving stack traces and displaying them via
 printf(9)    and KTR.

Contributed by:		Antoine Brodin <antoine.brodin@laposte.net>
Concept code from:	Neal Fachan <neal@isilon.com>
---
 sys/alpha/alpha/db_trace.c | 41 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

(limited to 'sys/alpha')

diff --git a/sys/alpha/alpha/db_trace.c b/sys/alpha/alpha/db_trace.c
index fcee2f3..12b6af4 100644
--- a/sys/alpha/alpha/db_trace.c
+++ b/sys/alpha/alpha/db_trace.c
@@ -47,7 +47,9 @@ __FBSDID("$FreeBSD$");
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/kdb.h>
+#include <sys/linker.h>
 #include <sys/proc.h>
+#include <sys/stack.h>
 #include <sys/sysent.h>
 
 #include <machine/db_machdep.h>
@@ -348,6 +350,45 @@ db_trace_thread(struct thread *thr, int count)
 		    count));
 }
 
+void
+stack_save(struct stack *st)
+{
+	struct prologue_info pi;
+	linker_symval_t symval;
+	c_linker_sym_t sym;
+	vm_offset_t callpc, frame;
+	long offset;
+	register_t pc, sp;
+
+	stack_zero(st);
+	__asm __volatile(
+		"	mov $30,%0 \n"
+		"	lda %1,1f \n"
+		"1:\n"
+		: "=r" (sp), "=r" (pc));
+	callpc = (vm_offset_t)pc;
+	frame = (vm_offset_t)sp;
+	while (1) {
+		/*
+		 * search_symbol/symbol_values are slow
+		 */
+		if (linker_ddb_search_symbol((caddr_t)callpc, &sym, &offset) != 0)
+			break;
+		if (linker_ddb_symbol_values(sym, &symval) != 0)
+			break;
+		if (callpc < (vm_offset_t)symval.value)
+			break;
+		if (stack_put(st, callpc) == -1)
+			break;
+		if (decode_prologue(callpc, (db_addr_t)symval.value, &pi))
+			break;
+		if ((pi.pi_regmask & (1 << 26)) == 0)
+			break;
+		callpc = *(vm_offset_t *)(frame + pi.pi_reg_offset[26]);
+		frame += pi.pi_frame_size;
+	}
+}
+
 int
 db_md_set_watchpoint(addr, size)
 	db_expr_t addr;
-- 
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