From d635711daa98be86d4c7fd01499c34f566b54ccb Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Fri, 10 Jun 2016 05:30:17 -0300
Subject: Linux-libre 4.6.2-gnu

---
 arch/s390/kernel/stacktrace.c | 93 ++++++++++++-------------------------------
 1 file changed, 25 insertions(+), 68 deletions(-)

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

diff --git a/arch/s390/kernel/stacktrace.c b/arch/s390/kernel/stacktrace.c
index 8f64ebd63..44f84b23d 100644
--- a/arch/s390/kernel/stacktrace.c
+++ b/arch/s390/kernel/stacktrace.c
@@ -10,78 +10,39 @@
 #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)
+static int __save_address(void *data, unsigned long address, int nosched)
 {
-	struct stack_frame *sf;
-	struct pt_regs *regs;
-	unsigned long addr;
+	struct stack_trace *trace = data;
 
-	while(1) {
-		if (sp < low || sp > high)
-			return sp;
-		sf = (struct stack_frame *)sp;
-		while(1) {
-			addr = sf->gprs[8];
-			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;
-			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;
-		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];
+	if (nosched && in_sched_functions(address))
+		return 0;
+	if (trace->skip > 0) {
+		trace->skip--;
+		return 0;
 	}
+	if (trace->nr_entries < trace->max_entries) {
+		trace->entries[trace->nr_entries++] = address;
+		return 0;
+	}
+	return 1;
 }
 
-static void __save_stack_trace(struct stack_trace *trace, unsigned long sp)
+static int save_address(void *data, unsigned long address)
 {
-	unsigned long new_sp, frame_size;
+	return __save_address(data, address, 0);
+}
 
-	frame_size = STACK_FRAME_OVERHEAD + sizeof(struct pt_regs);
-	new_sp = save_context_stack(trace, sp,
-			S390_lowcore.panic_stack + frame_size - PAGE_SIZE,
-			S390_lowcore.panic_stack + frame_size, 1);
-	new_sp = save_context_stack(trace, new_sp,
-			S390_lowcore.async_stack + frame_size - ASYNC_SIZE,
-			S390_lowcore.async_stack + frame_size, 1);
-	save_context_stack(trace, new_sp,
-			   S390_lowcore.thread_info,
-			   S390_lowcore.thread_info + THREAD_SIZE, 1);
+static int save_address_nosched(void *data, unsigned long address)
+{
+	return __save_address(data, address, 1);
 }
 
 void save_stack_trace(struct stack_trace *trace)
 {
-	register unsigned long r15 asm ("15");
 	unsigned long sp;
 
-	sp = r15;
-	__save_stack_trace(trace, sp);
+	sp = current_stack_pointer();
+	dump_trace(save_address, trace, NULL, sp);
 	if (trace->nr_entries < trace->max_entries)
 		trace->entries[trace->nr_entries++] = ULONG_MAX;
 }
@@ -89,16 +50,12 @@ EXPORT_SYMBOL_GPL(save_stack_trace);
 
 void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
 {
-	unsigned long sp, low, high;
+	unsigned long sp;
 
 	sp = tsk->thread.ksp;
-	if (tsk == current) {
-		/* Get current stack pointer. */
-		asm volatile("la %0,0(15)" : "=a" (sp));
-	}
-	low = (unsigned long) task_stack_page(tsk);
-	high = (unsigned long) task_pt_regs(tsk);
-	save_context_stack(trace, sp, low, high, 0);
+	if (tsk == current)
+		sp = current_stack_pointer();
+	dump_trace(save_address_nosched, trace, tsk, sp);
 	if (trace->nr_entries < trace->max_entries)
 		trace->entries[trace->nr_entries++] = ULONG_MAX;
 }
@@ -109,7 +66,7 @@ void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
 	unsigned long sp;
 
 	sp = kernel_stack_pointer(regs);
-	__save_stack_trace(trace, sp);
+	dump_trace(save_address, trace, NULL, sp);
 	if (trace->nr_entries < trace->max_entries)
 		trace->entries[trace->nr_entries++] = ULONG_MAX;
 }
-- 
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