Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull s390 fixes from Martin Schwidefsky:
 "Several bug fixes:

   - There are four different stack tracers, and three of them have
     bugs.  For 4.5 the bugs are fixed and we prepare a cleanup patch
     for the next merge window.

   - Three bug fixes for the dasd driver in regard to parallel access
     volumes and the new max_dev_sectors block device queue limit

   - The irq restore optimization needs a fixup for memcpy_real

   - The diagnose trace code has a conflict with lockdep"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/dasd: fix performance drop
  s390/maccess: reduce stnsm instructions
  s390/diag: avoid lockdep recursion
  s390/dasd: fix refcount for PAV reassignment
  s390/dasd: prevent incorrect length error under z/VM after PAV changes
  s390: fix DAT off memory access, e.g. on kdump
  s390/oprofile: fix address range for asynchronous stack
  s390/perf_event: fix address range for asynchronous stack
  s390/stacktrace: add save_stack_trace_regs()
  s390/stacktrace: save full stack traces
  s390/stacktrace: add missing end marker
  s390/stacktrace: fix address ranges for asynchronous and panic stack
  s390/stacktrace: fix save_stack_trace_tsk() for current task

5 files changed, 55 insertions, 23 deletions

diff --git a/arch/s390/kernel/perf_event.c b/arch/s390/kernel/perf_event.c
index cfcba2dd9bb5..0943b11a2f6e 100644
--- a/arch/s390/kernel/perf_event.c
+++ b/arch/s390/kernel/perf_event.c
@@ -260,12 +260,13 @@ static unsigned long __store_trace(struct perf_callchain_entry *entry,
 void perf_callchain_kernel(struct perf_callchain_entry *entry,
 			   struct pt_regs *regs)
 {
-	unsigned long head;
+	unsigned long head, frame_size;
 	struct stack_frame *head_sf;
 
 	if (user_mode(regs))
 		return;
 
+	frame_size = STACK_FRAME_OVERHEAD + sizeof(struct pt_regs);
 	head = regs->gprs[15];
 	head_sf = (struct stack_frame *) head;
 
@@ -273,8 +274,9 @@ void perf_callchain_kernel(struct perf_callchain_entry *entry,
 		return;
 
 	head = head_sf->back_chain;
-	head = __store_trace(entry, head, S390_lowcore.async_stack - ASYNC_SIZE,
-			     S390_lowcore.async_stack);
+	head = __store_trace(entry, head,
+			     S390_lowcore.async_stack + frame_size - ASYNC_SIZE,
+			     S390_lowcore.async_stack + frame_size);
 
 	__store_trace(entry, head, S390_lowcore.thread_info,
 		      S390_lowcore.thread_info + THREAD_SIZE);
diff --git a/arch/s390/kernel/stacktrace.c b/arch/s390/kernel/stacktrace.c
index 5acba3cb7220..8f64ebd63767 100644
--- a/arch/s390/kernel/stacktrace.c
+++ b/arch/s390/kernel/stacktrace.c
@@ -59,26 +59,32 @@ 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;
-	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)
@@ -86,6 +92,10 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
 	unsigned long sp, low, high;
 
 	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);
@@ -93,3 +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);
diff --git a/arch/s390/kernel/trace.c b/arch/s390/kernel/trace.c
index 21a5df99552b..dde7654f5c68 100644
--- a/arch/s390/kernel/trace.c
+++ b/arch/s390/kernel/trace.c
@@ -18,6 +18,9 @@ void trace_s390_diagnose_norecursion(int diag_nr)
 	unsigned long flags;
 	unsigned int *depth;
 
+	/* Avoid lockdep recursion. */
+	if (IS_ENABLED(CONFIG_LOCKDEP))
+		return;
 	local_irq_save(flags);
 	depth = this_cpu_ptr(&diagnose_trace_depth);
 	if (*depth == 0) {
diff --git a/arch/s390/mm/maccess.c b/arch/s390/mm/maccess.c
index fec59c067d0d..792f9c63fbca 100644
--- a/arch/s390/mm/maccess.c
+++ b/arch/s390/mm/maccess.c
@@ -93,15 +93,19 @@ static int __memcpy_real(void *dest, void *src, size_t count)
  */
 int memcpy_real(void *dest, void *src, size_t count)
 {
+	int irqs_disabled, rc;
 	unsigned long flags;
-	int rc;
 
 	if (!count)
 		return 0;
-	local_irq_save(flags);
-	__arch_local_irq_stnsm(0xfbUL);
+	flags = __arch_local_irq_stnsm(0xf8UL);
+	irqs_disabled = arch_irqs_disabled_flags(flags);
+	if (!irqs_disabled)
+		trace_hardirqs_off();
 	rc = __memcpy_real(dest, src, count);
-	local_irq_restore(flags);
+	if (!irqs_disabled)
+		trace_hardirqs_on();
+	__arch_local_irq_ssm(flags);
 	return rc;
 }
 
diff --git a/arch/s390/oprofile/backtrace.c b/arch/s390/oprofile/backtrace.c
index fe0bfe370c45..1884e1759529 100644
--- a/arch/s390/oprofile/backtrace.c
+++ b/arch/s390/oprofile/backtrace.c
@@ -54,12 +54,13 @@ __show_trace(unsigned int *depth, unsigned long sp,
 
 void s390_backtrace(struct pt_regs * const regs, unsigned int depth)
 {
-	unsigned long head;
+	unsigned long head, frame_size;
 	struct stack_frame* head_sf;
 
 	if (user_mode(regs))
 		return;
 
+	frame_size = STACK_FRAME_OVERHEAD + sizeof(struct pt_regs);
 	head = regs->gprs[15];
 	head_sf = (struct stack_frame*)head;
 
@@ -68,8 +69,9 @@ void s390_backtrace(struct pt_regs * const regs, unsigned int depth)
 
 	head = head_sf->back_chain;
 
-	head = __show_trace(&depth, head, S390_lowcore.async_stack - ASYNC_SIZE,
-			    S390_lowcore.async_stack);
+	head = __show_trace(&depth, head,
+			    S390_lowcore.async_stack + frame_size - ASYNC_SIZE,
+			    S390_lowcore.async_stack + frame_size);
 
 	__show_trace(&depth, head, S390_lowcore.thread_info,
 		     S390_lowcore.thread_info + THREAD_SIZE);