From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Wed, 5 Aug 2015 17:04:01 -0300
Subject: Initial import

---
 arch/s390/kernel/stacktrace.c | 96 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 96 insertions(+)
 create mode 100644 arch/s390/kernel/stacktrace.c

(limited to 'arch/s390/kernel/stacktrace.c')

diff --git a/arch/s390/kernel/stacktrace.c b/arch/s390/kernel/stacktrace.c
new file mode 100644
index 000000000..1785cd822
--- /dev/null
+++ b/arch/s390/kernel/stacktrace.c
@@ -0,0 +1,96 @@
+/*
+ * Stack trace management functions
+ *
+ *  Copyright IBM Corp. 2006
+ *  Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
+ */
+
+#include <linux/sched.h>
+#include <linux/stacktrace.h>
+#include <linux/kallsyms.h>
+#include <linux/module.h>
+
+static unsigned long save_context_stack(struct stack_trace *trace,
+					unsigned long sp,
+					unsigned long low,
+					unsigned long high,
+					int savesched)
+{
+	struct stack_frame *sf;
+	struct pt_regs *regs;
+	unsigned long addr;
+
+	while(1) {
+		sp &= PSW_ADDR_INSN;
+		if (sp < low || sp > high)
+			return sp;
+		sf = (struct stack_frame *)sp;
+		while(1) {
+			addr = sf->gprs[8] & PSW_ADDR_INSN;
+			if (!trace->skip)
+				trace->entries[trace->nr_entries++] = addr;
+			else
+				trace->skip--;
+			if (trace->nr_entries >= trace->max_entries)
+				return sp;
+			low = sp;
+			sp = sf->back_chain & PSW_ADDR_INSN;
+			if (!sp)
+				break;
+			if (sp <= low || sp > high - sizeof(*sf))
+				return sp;
+			sf = (struct stack_frame *)sp;
+		}
+		/* Zero backchain detected, check for interrupt frame. */
+		sp = (unsigned long)(sf + 1);
+		if (sp <= low || sp > high - sizeof(*regs))
+			return sp;
+		regs = (struct pt_regs *)sp;
+		addr = regs->psw.addr & PSW_ADDR_INSN;
+		if (savesched || !in_sched_functions(addr)) {
+			if (!trace->skip)
+				trace->entries[trace->nr_entries++] = addr;
+			else
+				trace->skip--;
+		}
+		if (trace->nr_entries >= trace->max_entries)
+			return sp;
+		low = sp;
+		sp = regs->gprs[15];
+	}
+}
+
+void save_stack_trace(struct stack_trace *trace)
+{
+	register unsigned long sp asm ("15");
+	unsigned long orig_sp, new_sp;
+
+	orig_sp = sp & PSW_ADDR_INSN;
+	new_sp = save_context_stack(trace, orig_sp,
+				    S390_lowcore.panic_stack - PAGE_SIZE,
+				    S390_lowcore.panic_stack, 1);
+	if (new_sp != orig_sp)
+		return;
+	new_sp = save_context_stack(trace, new_sp,
+				    S390_lowcore.async_stack - ASYNC_SIZE,
+				    S390_lowcore.async_stack, 1);
+	if (new_sp != orig_sp)
+		return;
+	save_context_stack(trace, new_sp,
+			   S390_lowcore.thread_info,
+			   S390_lowcore.thread_info + THREAD_SIZE, 1);
+}
+EXPORT_SYMBOL_GPL(save_stack_trace);
+
+void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
+{
+	unsigned long sp, low, high;
+
+	sp = tsk->thread.ksp & PSW_ADDR_INSN;
+	low = (unsigned long) task_stack_page(tsk);
+	high = (unsigned long) task_pt_regs(tsk);
+	save_context_stack(trace, sp, low, high, 0);
+	if (trace->nr_entries < trace->max_entries)
+		trace->entries[trace->nr_entries++] = ULONG_MAX;
+}
+EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
-- 
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