patch-2.3.43 linux/arch/ia64/kernel/unwind.c

• Lines: 119
• Date: Sun Feb 6 18:42:40 2000
• Orig file: v2.3.42/linux/arch/ia64/kernel/unwind.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.3.42/linux/arch/ia64/kernel/unwind.c linux/arch/ia64/kernel/unwind.c
@@ -0,0 +1,118 @@
+/*
+ * Copyright (C) 1999 Hewlett-Packard Co
+ * Copyright (C) 1999 David Mosberger-Tang <davidm@hpl.hp.com>
+ */
+#include <linux/kernel.h>
+#include <linux/sched.h>
+
+#include <asm/unwind.h>
+
+void
+ia64_unwind_init_from_blocked_task (struct ia64_frame_info *info, struct task_struct *t)
+{
+	struct switch_stack *sw = (struct switch_stack *) (t->thread.ksp + 16);
+	unsigned long sol, limit, top;
+
+	memset(info, 0, sizeof(*info));
+
+	sol = (sw->ar_pfs >> 7) & 0x7f;	/* size of locals */
+
+	limit = (unsigned long) t + IA64_RBS_OFFSET;
+	top   = sw->ar_bspstore;
+	if (top - (unsigned long) t >= IA64_STK_OFFSET)
+		top = limit;
+
+	info->regstk.limit = (unsigned long *) limit;
+	info->regstk.top   = (unsigned long *) top;
+	info->bsp	   = ia64_rse_skip_regs(info->regstk.top, -sol);
+	info->top_rnat	   = sw->ar_rnat;
+	info->cfm	   = sw->ar_pfs;
+	info->ip	   = sw->b0;
+}
+
+void
+ia64_unwind_init_from_current (struct ia64_frame_info *info, struct pt_regs *regs)
+{
+	struct switch_stack *sw = (struct switch_stack *) regs - 1;
+	unsigned long sol, sof, *bsp, limit, top;
+
+	limit = (unsigned long) current + IA64_RBS_OFFSET;
+	top   = sw->ar_bspstore;
+	if (top - (unsigned long) current >= IA64_STK_OFFSET)
+		top = limit;
+
+	memset(info, 0, sizeof(*info));
+
+	sol = (sw->ar_pfs >> 7) & 0x7f;	/* size of frame */
+	info->regstk.limit = (unsigned long *) limit;
+	info->regstk.top   = (unsigned long *) top;
+	info->top_rnat	   = sw->ar_rnat;
+
+	/* this gives us the bsp top level frame (kdb interrupt frame): */
+	bsp = ia64_rse_skip_regs((unsigned long *) top, -sol);
+
+	/* now skip past the interrupt frame: */
+	sof = regs->cr_ifs & 0x7f;	/* size of frame */
+	info->cfm = regs->cr_ifs;
+	info->bsp = ia64_rse_skip_regs(bsp, -sof);
+	info->ip  = regs->cr_iip;
+}
+
+static unsigned long
+read_reg (struct ia64_frame_info *info, int regnum, int *is_nat)
+{
+	unsigned long *addr, *rnat_addr, rnat;
+
+	addr = ia64_rse_skip_regs(info->bsp, regnum);
+	if (addr < info->regstk.limit || addr >= info->regstk.top || ((long) addr & 0x7) != 0) {
+		*is_nat = 1;
+		return 0xdeadbeefdeadbeef;
+	}
+	rnat_addr = ia64_rse_rnat_addr(addr);
+
+	if (rnat_addr >= info->regstk.top)
+		rnat = info->top_rnat;
+	else
+		rnat = *rnat_addr;
+	*is_nat = (rnat & (1UL << ia64_rse_slot_num(addr))) != 0;
+	return *addr;
+}
+
+/*
+ * On entry, info->regstk.top should point to the register backing
+ * store for r32.
+ */
+int
+ia64_unwind_to_previous_frame (struct ia64_frame_info *info)
+{
+	unsigned long sol, cfm = info->cfm;
+	int is_nat;
+
+	sol = (cfm >> 7) & 0x7f;	/* size of locals */
+
+	/*
+	 * In general, we would have to make use of unwind info to
+	 * unwind an IA-64 stack, but for now gcc uses a special
+	 * convention that makes this possible without full-fledged
+	 * unwindo info.  Specifically, we expect "rp" in the second
+	 * last, and "ar.pfs" in the last local register, so the
+	 * number of locals in a frame must be at least two.  If it's
+	 * less than that, we reached the end of the C call stack.
+	 */
+	if (sol < 2)
+		return -1;
+
+	info->ip = read_reg(info, sol - 2, &is_nat);
+	if (is_nat)
+		return -1;
+
+	cfm = read_reg(info, sol - 1, &is_nat);
+	if (is_nat)
+		return -1;
+
+	sol = (cfm >> 7) & 0x7f;
+
+	info->cfm = cfm;
+	info->bsp = ia64_rse_skip_regs(info->bsp, -sol);
+	return 0;
+}