From 03dd4cb26d967f9588437b0fc9cc0e8353322bb7 Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Fri, 25 Mar 2016 03:53:42 -0300
Subject: Linux-libre 4.5-gnu

---
 arch/s390/kernel/stacktrace.c | 56 +++++++++++++++++++++++++++++--------------
 1 file changed, 38 insertions(+), 18 deletions(-)

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

diff --git a/arch/s390/kernel/stacktrace.c b/arch/s390/kernel/stacktrace.c
index 1785cd822..8f64ebd63 100644
--- a/arch/s390/kernel/stacktrace.c
+++ b/arch/s390/kernel/stacktrace.c
@@ -21,12 +21,11 @@ static unsigned long save_context_stack(struct stack_trace *trace,
 	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;
+			addr = sf->gprs[8];
 			if (!trace->skip)
 				trace->entries[trace->nr_entries++] = addr;
 			else
@@ -34,7 +33,7 @@ static unsigned long save_context_stack(struct stack_trace *trace,
 			if (trace->nr_entries >= trace->max_entries)
 				return sp;
 			low = sp;
-			sp = sf->back_chain & PSW_ADDR_INSN;
+			sp = sf->back_chain;
 			if (!sp)
 				break;
 			if (sp <= low || sp > high - sizeof(*sf))
@@ -46,7 +45,7 @@ static unsigned long save_context_stack(struct stack_trace *trace,
 		if (sp <= low || sp > high - sizeof(*regs))
 			return sp;
 		regs = (struct pt_regs *)sp;
-		addr = regs->psw.addr & PSW_ADDR_INSN;
+		addr = regs->psw.addr;
 		if (savesched || !in_sched_functions(addr)) {
 			if (!trace->skip)
 				trace->entries[trace->nr_entries++] = addr;
@@ -60,33 +59,43 @@ static unsigned long save_context_stack(struct stack_trace *trace,
 	}
 }
 
-void save_stack_trace(struct stack_trace *trace)
+static void __save_stack_trace(struct stack_trace *trace, unsigned long sp)
 {
-	register unsigned long sp asm ("15");
-	unsigned long orig_sp, new_sp;
+	unsigned long new_sp, frame_size;
 
-	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;
+	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 - ASYNC_SIZE,
-				    S390_lowcore.async_stack, 1);
-	if (new_sp != orig_sp)
-		return;
+			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);
 }
+
+void save_stack_trace(struct stack_trace *trace)
+{
+	register unsigned long r15 asm ("15");
+	unsigned long sp;
+
+	sp = r15;
+	__save_stack_trace(trace, sp);
+	if (trace->nr_entries < trace->max_entries)
+		trace->entries[trace->nr_entries++] = ULONG_MAX;
+}
 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;
+	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);
@@ -94,3 +103,14 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
 		trace->entries[trace->nr_entries++] = ULONG_MAX;
 }
 EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
+
+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);
+	if (trace->nr_entries < trace->max_entries)
+		trace->entries[trace->nr_entries++] = ULONG_MAX;
+}
+EXPORT_SYMBOL_GPL(save_stack_trace_regs);
-- 
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