10 files changed, 166 insertions, 135 deletions

diff --git a/arch/csky/kernel/Makefile b/arch/csky/kernel/Makefile
index fd6d9dc8b7f3..37f37c0e934a 100644
--- a/arch/csky/kernel/Makefile
+++ b/arch/csky/kernel/Makefile
@@ -3,7 +3,7 @@ extra-y := head.o vmlinux.lds
 
 obj-y += entry.o atomic.o signal.o traps.o irq.o time.o vdso.o
 obj-y += power.o syscall.o syscall_table.o setup.o
-obj-y += process.o cpu-probe.o ptrace.o dumpstack.o
+obj-y += process.o cpu-probe.o ptrace.o stacktrace.o
 obj-y += probes/
 
 obj-$(CONFIG_MODULES)			+= module.o
diff --git a/arch/csky/kernel/asm-offsets.c b/arch/csky/kernel/asm-offsets.c
index f8be348df9e4..17479860d43d 100644
--- a/arch/csky/kernel/asm-offsets.c
+++ b/arch/csky/kernel/asm-offsets.c
@@ -18,8 +18,7 @@ int main(void)
 	DEFINE(TASK_ACTIVE_MM,    offsetof(struct task_struct, active_mm));
 
 	/* offsets into the thread struct */
-	DEFINE(THREAD_KSP,        offsetof(struct thread_struct, ksp));
-	DEFINE(THREAD_SR,         offsetof(struct thread_struct, sr));
+	DEFINE(THREAD_KSP,        offsetof(struct thread_struct, sp));
 	DEFINE(THREAD_FESR,       offsetof(struct thread_struct, user_fp.fesr));
 	DEFINE(THREAD_FCR,        offsetof(struct thread_struct, user_fp.fcr));
 	DEFINE(THREAD_FPREG,      offsetof(struct thread_struct, user_fp.vr));
diff --git a/arch/csky/kernel/dumpstack.c b/arch/csky/kernel/dumpstack.c
deleted file mode 100644
index d67f9777cfd9..000000000000
--- a/arch/csky/kernel/dumpstack.c
+++ /dev/null
@@ -1,49 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
-
-#include <linux/ptrace.h>
-
-int kstack_depth_to_print = 48;
-
-void show_trace(unsigned long *stack)
-{
-	unsigned long *stack_end;
-	unsigned long *stack_start;
-	unsigned long *fp;
-	unsigned long addr;
-
-	addr = (unsigned long) stack & THREAD_MASK;
-	stack_start = (unsigned long *) addr;
-	stack_end = (unsigned long *) (addr + THREAD_SIZE);
-
-	fp = stack;
-	pr_info("\nCall Trace:");
-
-	while (fp > stack_start && fp < stack_end) {
-#ifdef CONFIG_STACKTRACE
-		addr	= fp[1];
-		fp	= (unsigned long *) fp[0];
-#else
-		addr	= *fp++;
-#endif
-		if (__kernel_text_address(addr))
-			pr_cont("\n[<%08lx>] %pS", addr, (void *)addr);
-	}
-	pr_cont("\n");
-}
-
-void show_stack(struct task_struct *task, unsigned long *stack)
-{
-	if (!stack) {
-		if (task)
-			stack = (unsigned long *)thread_saved_fp(task);
-		else
-#ifdef CONFIG_STACKTRACE
-			asm volatile("mov %0, r8\n":"=r"(stack)::"memory");
-#else
-			stack = (unsigned long *)&stack;
-#endif
-	}
-
-	show_trace(stack);
-}
diff --git a/arch/csky/kernel/entry.S b/arch/csky/kernel/entry.S
index 364819536f2e..3760397fdd3d 100644
--- a/arch/csky/kernel/entry.S
+++ b/arch/csky/kernel/entry.S
@@ -330,11 +330,6 @@ ENTRY(__switch_to)
 	lrw	a3, TASK_THREAD
 	addu	a3, a0
 
-	mfcr	a2, psr			/* Save PSR value */
-	stw	a2, (a3, THREAD_SR)	/* Save PSR in task struct */
-	bclri	a2, 6			/* Disable interrupts */
-	mtcr	a2, psr
-
 	SAVE_SWITCH_STACK
 
 	stw	sp, (a3, THREAD_KSP)
@@ -345,12 +340,9 @@ ENTRY(__switch_to)
 
 	ldw	sp, (a3, THREAD_KSP)	/* Set next kernel sp */
 
-	ldw	a2, (a3, THREAD_SR)	/* Set next PSR */
-	mtcr	a2, psr
-
 #if  defined(__CSKYABIV2__)
-	addi	r7, a1, TASK_THREAD_INFO
-	ldw	tls, (r7, TINFO_TP_VALUE)
+	addi	a3, a1, TASK_THREAD_INFO
+	ldw	tls, (a3, TINFO_TP_VALUE)
 #endif
 
 	RESTORE_SWITCH_STACK
diff --git a/arch/csky/kernel/ftrace.c b/arch/csky/kernel/ftrace.c
index 44628e3f7fa6..3c425b84e3be 100644
--- a/arch/csky/kernel/ftrace.c
+++ b/arch/csky/kernel/ftrace.c
@@ -202,6 +202,7 @@ int ftrace_disable_ftrace_graph_caller(void)
 #endif /* CONFIG_DYNAMIC_FTRACE */
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 
+#ifdef CONFIG_DYNAMIC_FTRACE
 #ifndef CONFIG_CPU_HAS_ICACHE_INS
 struct ftrace_modify_param {
 	int command;
@@ -231,6 +232,7 @@ void arch_ftrace_update_code(int command)
 	stop_machine(__ftrace_modify_code, &param, cpu_online_mask);
 }
 #endif
+#endif /* CONFIG_DYNAMIC_FTRACE */
 
 /* _mcount is defined in abi's mcount.S */
 EXPORT_SYMBOL(_mcount);
diff --git a/arch/csky/kernel/perf_callchain.c b/arch/csky/kernel/perf_callchain.c
index e68ff375c8f8..ab55e98ee8f6 100644
--- a/arch/csky/kernel/perf_callchain.c
+++ b/arch/csky/kernel/perf_callchain.c
@@ -12,12 +12,17 @@ struct stackframe {
 
 static int unwind_frame_kernel(struct stackframe *frame)
 {
-	if (kstack_end((void *)frame->fp))
+	unsigned long low = (unsigned long)task_stack_page(current);
+	unsigned long high = low + THREAD_SIZE;
+
+	if (unlikely(frame->fp < low || frame->fp > high))
 		return -EPERM;
-	if (frame->fp & 0x3 || frame->fp < TASK_SIZE)
+
+	if (kstack_end((void *)frame->fp) || frame->fp & 0x3)
 		return -EPERM;
 
 	*frame = *(struct stackframe *)frame->fp;
+
 	if (__kernel_text_address(frame->lr)) {
 		int graph = 0;
 
diff --git a/arch/csky/kernel/probes/uprobes.c b/arch/csky/kernel/probes/uprobes.c
index b3a56c260e3e..1a9e0961b2b5 100644
--- a/arch/csky/kernel/probes/uprobes.c
+++ b/arch/csky/kernel/probes/uprobes.c
@@ -11,6 +11,11 @@
 
 #define UPROBE_TRAP_NR	UINT_MAX
 
+bool is_swbp_insn(uprobe_opcode_t *insn)
+{
+	return (*insn & 0xffff) == UPROBE_SWBP_INSN;
+}
+
 unsigned long uprobe_get_swbp_addr(struct pt_regs *regs)
 {
 	return instruction_pointer(regs);
diff --git a/arch/csky/kernel/process.c b/arch/csky/kernel/process.c
index f7b231ca269a..8b3fad062ab2 100644
--- a/arch/csky/kernel/process.c
+++ b/arch/csky/kernel/process.c
@@ -35,7 +35,7 @@ void flush_thread(void){}
  */
 unsigned long thread_saved_pc(struct task_struct *tsk)
 {
-	struct switch_stack *sw = (struct switch_stack *)tsk->thread.ksp;
+	struct switch_stack *sw = (struct switch_stack *)tsk->thread.sp;
 
 	return sw->r15;
 }
@@ -56,8 +56,8 @@ int copy_thread_tls(unsigned long clone_flags,
 	childstack = ((struct switch_stack *) childregs) - 1;
 	memset(childstack, 0, sizeof(struct switch_stack));
 
-	/* setup ksp for switch_to !!! */
-	p->thread.ksp = (unsigned long)childstack;
+	/* setup thread.sp for switch_to !!! */
+	p->thread.sp = (unsigned long)childstack;
 
 	if (unlikely(p->flags & PF_KTHREAD)) {
 		memset(childregs, 0, sizeof(struct pt_regs));
@@ -98,37 +98,6 @@ int dump_task_regs(struct task_struct *tsk, elf_gregset_t *pr_regs)
 	return 1;
 }
 
-unsigned long get_wchan(struct task_struct *p)
-{
-	unsigned long lr;
-	unsigned long *fp, *stack_start, *stack_end;
-	int count = 0;
-
-	if (!p || p == current || p->state == TASK_RUNNING)
-		return 0;
-
-	stack_start = (unsigned long *)end_of_stack(p);
-	stack_end = (unsigned long *)(task_stack_page(p) + THREAD_SIZE);
-
-	fp = (unsigned long *) thread_saved_fp(p);
-	do {
-		if (fp < stack_start || fp > stack_end)
-			return 0;
-#ifdef CONFIG_STACKTRACE
-		lr = fp[1];
-		fp = (unsigned long *)fp[0];
-#else
-		lr = *fp++;
-#endif
-		if (!in_sched_functions(lr) &&
-		    __kernel_text_address(lr))
-			return lr;
-	} while (count++ < 16);
-
-	return 0;
-}
-EXPORT_SYMBOL(get_wchan);
-
 #ifndef CONFIG_CPU_PM_NONE
 void arch_cpu_idle(void)
 {
diff --git a/arch/csky/kernel/ptrace.c b/arch/csky/kernel/ptrace.c
index 21ac2608f205..5a82230bddf9 100644
--- a/arch/csky/kernel/ptrace.c
+++ b/arch/csky/kernel/ptrace.c
@@ -41,6 +41,9 @@ static void singlestep_disable(struct task_struct *tsk)
 
 	regs = task_pt_regs(tsk);
 	regs->sr = (regs->sr & TRACE_MODE_MASK) | TRACE_MODE_RUN;
+
+	/* Enable irq */
+	regs->sr |= BIT(6);
 }
 
 static void singlestep_enable(struct task_struct *tsk)
@@ -49,6 +52,9 @@ static void singlestep_enable(struct task_struct *tsk)
 
 	regs = task_pt_regs(tsk);
 	regs->sr = (regs->sr & TRACE_MODE_MASK) | TRACE_MODE_SI;
+
+	/* Disable irq */
+	regs->sr &= ~BIT(6);
 }
 
 /*
diff --git a/arch/csky/kernel/stacktrace.c b/arch/csky/kernel/stacktrace.c
index fec777a643f1..92809e1da723 100644
--- a/arch/csky/kernel/stacktrace.c
+++ b/arch/csky/kernel/stacktrace.c
@@ -1,57 +1,159 @@
 // SPDX-License-Identifier: GPL-2.0
-/* Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd. */
 
 #include <linux/sched/debug.h>
 #include <linux/sched/task_stack.h>
 #include <linux/stacktrace.h>
 #include <linux/ftrace.h>
+#include <linux/ptrace.h>
 
-void save_stack_trace(struct stack_trace *trace)
+#ifdef CONFIG_FRAME_POINTER
+
+struct stackframe {
+	unsigned long fp;
+	unsigned long ra;
+};
+
+void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,
+			     bool (*fn)(unsigned long, void *), void *arg)
 {
-	save_stack_trace_tsk(current, trace);
+	unsigned long fp, sp, pc;
+
+	if (regs) {
+		fp = frame_pointer(regs);
+		sp = user_stack_pointer(regs);
+		pc = instruction_pointer(regs);
+	} else if (task == NULL || task == current) {
+		const register unsigned long current_sp __asm__ ("sp");
+		const register unsigned long current_fp __asm__ ("r8");
+		fp = current_fp;
+		sp = current_sp;
+		pc = (unsigned long)walk_stackframe;
+	} else {
+		/* task blocked in __switch_to */
+		fp = thread_saved_fp(task);
+		sp = thread_saved_sp(task);
+		pc = thread_saved_lr(task);
+	}
+
+	for (;;) {
+		unsigned long low, high;
+		struct stackframe *frame;
+
+		if (unlikely(!__kernel_text_address(pc) || fn(pc, arg)))
+			break;
+
+		/* Validate frame pointer */
+		low = sp;
+		high = ALIGN(sp, THREAD_SIZE);
+		if (unlikely(fp < low || fp > high || fp & 0x3))
+			break;
+		/* Unwind stack frame */
+		frame = (struct stackframe *)fp;
+		sp = fp;
+		fp = frame->fp;
+		pc = ftrace_graph_ret_addr(current, NULL, frame->ra,
+					   (unsigned long *)(fp - 8));
+	}
 }
-EXPORT_SYMBOL_GPL(save_stack_trace);
 
-void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
+#else /* !CONFIG_FRAME_POINTER */
+
+static void notrace walk_stackframe(struct task_struct *task,
+	struct pt_regs *regs, bool (*fn)(unsigned long, void *), void *arg)
 {
-	unsigned long *fp, *stack_start, *stack_end;
-	unsigned long addr;
-	int skip = trace->skip;
-	int savesched;
-	int graph_idx = 0;
+	unsigned long sp, pc;
+	unsigned long *ksp;
 
-	if (tsk == current) {
-		asm volatile("mov %0, r8\n":"=r"(fp));
-		savesched = 1;
+	if (regs) {
+		sp = user_stack_pointer(regs);
+		pc = instruction_pointer(regs);
+	} else if (task == NULL || task == current) {
+		const register unsigned long current_sp __asm__ ("sp");
+		sp = current_sp;
+		pc = (unsigned long)walk_stackframe;
 	} else {
-		fp = (unsigned long *)thread_saved_fp(tsk);
-		savesched = 0;
+		/* task blocked in __switch_to */
+		sp = thread_saved_sp(task);
+		pc = thread_saved_lr(task);
 	}
 
-	addr = (unsigned long) fp & THREAD_MASK;
-	stack_start = (unsigned long *) addr;
-	stack_end = (unsigned long *) (addr + THREAD_SIZE);
-
-	while (fp > stack_start && fp < stack_end) {
-		unsigned long lpp, fpp;
+	if (unlikely(sp & 0x3))
+		return;
 
-		fpp = fp[0];
-		lpp = fp[1];
-		if (!__kernel_text_address(lpp))
+	ksp = (unsigned long *)sp;
+	while (!kstack_end(ksp)) {
+		if (__kernel_text_address(pc) && unlikely(fn(pc, arg)))
 			break;
-		else
-			lpp = ftrace_graph_ret_addr(tsk, &graph_idx, lpp, NULL);
-
-		if (savesched || !in_sched_functions(lpp)) {
-			if (skip) {
-				skip--;
-			} else {
-				trace->entries[trace->nr_entries++] = lpp;
-				if (trace->nr_entries >= trace->max_entries)
-					break;
-			}
-		}
-		fp = (unsigned long *)fpp;
+		pc = (*ksp++) - 0x4;
 	}
 }
+#endif /* CONFIG_FRAME_POINTER */
+
+static bool print_trace_address(unsigned long pc, void *arg)
+{
+	print_ip_sym(pc);
+	return false;
+}
+
+void show_stack(struct task_struct *task, unsigned long *sp)
+{
+	pr_cont("Call Trace:\n");
+	walk_stackframe(task, NULL, print_trace_address, NULL);
+}
+
+static bool save_wchan(unsigned long pc, void *arg)
+{
+	if (!in_sched_functions(pc)) {
+		unsigned long *p = arg;
+		*p = pc;
+		return true;
+	}
+	return false;
+}
+
+unsigned long get_wchan(struct task_struct *task)
+{
+	unsigned long pc = 0;
+
+	if (likely(task && task != current && task->state != TASK_RUNNING))
+		walk_stackframe(task, NULL, save_wchan, &pc);
+	return pc;
+}
+
+#ifdef CONFIG_STACKTRACE
+static bool __save_trace(unsigned long pc, void *arg, bool nosched)
+{
+	struct stack_trace *trace = arg;
+
+	if (unlikely(nosched && in_sched_functions(pc)))
+		return false;
+	if (unlikely(trace->skip > 0)) {
+		trace->skip--;
+		return false;
+	}
+
+	trace->entries[trace->nr_entries++] = pc;
+	return (trace->nr_entries >= trace->max_entries);
+}
+
+static bool save_trace(unsigned long pc, void *arg)
+{
+	return __save_trace(pc, arg, false);
+}
+
+/*
+ * Save stack-backtrace addresses into a stack_trace buffer.
+ */
+void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
+{
+	walk_stackframe(tsk, NULL, save_trace, trace);
+}
 EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
+
+void save_stack_trace(struct stack_trace *trace)
+{
+	save_stack_trace_tsk(NULL, trace);
+}
+EXPORT_SYMBOL_GPL(save_stack_trace);
+
+#endif /* CONFIG_STACKTRACE */