1 files changed, 72 insertions, 0 deletions
diff --git a/runtime/stack-arm.c b/runtime/stack-arm.c
new file mode 100644
index 00000000..9d3307ec
--- /dev/null
+++ b/runtime/stack-arm.c
@@ -0,0 +1,72 @@
+/* -*- linux-c -*-
+ * arm stack tracing functions
+ * Copyright (C) 2007 Quentin Barnes
+ *
+ * This file is part of systemtap, and is free software.  You can
+ * redistribute it and/or modify it under the terms of the GNU General
+ * Public License (GPL); either version 2, or (at your option) any
+ * later version.
+ */
+
+/*
+ * For STR and STM instructions, an ARM core may choose to use either
+ * a +8 or a +12 displacement from the current instruction's address.
+ * Whichever value is chosen for a given core, it must be the same for
+ * both instructions and may not change.  This function measures it.
+ */
+
+static int __init find_str_pc_offset(void)
+{
+	int addr;
+	int scratch;
+	int ret;
+
+	__asm__("sub	%[ret], pc, #4		\n\t"
+		"str	pc, %[addr]		\n\t"
+		"ldr	%[scr], %[addr]		\n\t"
+		"sub	%[ret], %[scr], %[ret]	\n\t"
+		: [ret] "=r" (ret), [scr] "=r" (scratch), [addr] "+m" (addr) );
+
+	return ret;
+}
+
+
+static void __stp_stack_print (struct pt_regs *regs, int verbose, int levels)
+{
+#if defined(CONFIG_FRAME_POINTER)
+	int		pc_offset = find_str_pc_offset();
+	unsigned long	*fp = (unsigned long *)regs->ARM_fp;
+	unsigned long	*next_fp, *pc;
+
+	if (levels == 0)
+		--levels;
+
+	while (fp && levels--) {
+		next_fp = (unsigned long *)*(fp - 3);
+		pc      = (unsigned long *)(*fp - pc_offset);
+
+		/* 0xe92dd8xx == stmfd sp!, { ..., fp, ip, lr, pc } */
+		if ((*pc & 0xffffd800) == 0xe92dd800) {
+			pc -= 1;
+
+			/* Varargs functions have two stmfd instructions. */
+			if ((*pc & 0xffff0000) == 0xe92d0000)
+				pc -= 1;
+		}
+
+		if (verbose) {
+			_stp_print_char(' ');
+			_stp_symbol_print((unsigned long)pc);
+			_stp_print_char('\n');
+		} else {
+			_stp_printf("%08lx ", pc);
+		}
+
+		/* Sanity check the next_fp. */
+		if (next_fp && next_fp <= fp)
+			break;
+
+		fp = next_fp;
+	}
+#endif
+}