Merge tag 'csky-for-linus-5.7-rc6' of git://github.com/c-sky/csky-linux

Pull csky updates from Guo Ren:

 - fix for copy_from/to_user (a hard-to-find bug, thx Viro)

 - fix for calltrace panic without FRAME_POINT

 - two fixes for perf

 - two build fixes

 - four fixes for non-fatal bugs (msa, rm dis_irq, cleanup psr,
   gdbmacros.txt)

* tag 'csky-for-linus-5.7-rc6' of git://github.com/c-sky/csky-linux:
  csky: Fixup raw_copy_from_user()
  csky: Fixup gdbmacros.txt with name sp in thread_struct
  csky: Fixup remove unnecessary save/restore PSR code
  csky: Fixup remove duplicate irq_disable
  csky: Fixup calltrace panic
  csky: Fixup perf callchain unwind
  csky: Fixup msa highest 3 bits mask
  csky: Fixup perf probe -x hungup
  csky: Fixup compile error for abiv1 entry.S
  csky/ftrace: Fixup error when disable CONFIG_DYNAMIC_FTRACE

arch/csky/Kconfig

@@ -8,6 +8,7 @@ config CSKY
 	select ARCH_HAS_SYNC_DMA_FOR_DEVICE
 	select ARCH_USE_BUILTIN_BSWAP
 	select ARCH_USE_QUEUED_RWLOCKS if NR_CPUS>2
+	select ARCH_WANT_FRAME_POINTERS if !CPU_CK610
 	select COMMON_CLK
 	select CLKSRC_MMIO
 	select CSKY_MPINTC if CPU_CK860
@@ -38,6 +39,7 @@ config CSKY
 	select HAVE_ARCH_TRACEHOOK
 	select HAVE_ARCH_AUDITSYSCALL
 	select HAVE_COPY_THREAD_TLS
+	select HAVE_DEBUG_BUGVERBOSE
 	select HAVE_DYNAMIC_FTRACE
 	select HAVE_DYNAMIC_FTRACE_WITH_REGS
 	select HAVE_FUNCTION_TRACER

arch/csky/Makefile

@@ -47,7 +47,7 @@ ifeq ($(CSKYABI),abiv2)
 KBUILD_CFLAGS += -mno-stack-size
 endif
 
-ifdef CONFIG_STACKTRACE
+ifdef CONFIG_FRAME_POINTER
 KBUILD_CFLAGS += -mbacktrace
 endif
 

arch/csky/abiv1/inc/abi/entry.h

@@ -167,8 +167,8 @@
 	 *   BA     Reserved  C   D   V
 	 */
 	cprcr	r6, cpcr30
-	lsri	r6, 28
-	lsli	r6, 28
+	lsri	r6, 29
+	lsli	r6, 29
 	addi	r6, 0xe
 	cpwcr	r6, cpcr30
 

arch/csky/abiv2/inc/abi/entry.h

@@ -285,8 +285,8 @@
 	 */
 	mfcr	r6, cr<30, 15> /* Get MSA0 */
 2:
-	lsri	r6, 28
-	lsli	r6, 28
+	lsri	r6, 29
+	lsli	r6, 29
 	addi	r6, 0x1ce
 	mtcr	r6, cr<30, 15> /* Set MSA0 */
 

arch/csky/abiv2/mcount.S

@@ -103,6 +103,8 @@ ENTRY(_mcount)
 	mov	a0, lr
 	subi	a0, 4
 	ldw	a1, (sp, 24)
+	lrw	a2, function_trace_op
+	ldw	a2, (a2, 0)
 
 	jsr	r26
 

arch/csky/include/asm/processor.h

@@ -41,8 +41,7 @@ extern struct cpuinfo_csky cpu_data[];
 #define TASK_UNMAPPED_BASE      (TASK_SIZE / 3)
 
 struct thread_struct {
-	unsigned long  ksp;       /* kernel stack pointer */
-	unsigned long  sr;        /* saved status register */
+	unsigned long  sp;        /* kernel stack pointer */
 	unsigned long  trap_no;   /* saved status register */
 
 	/* FPU regs */
@@ -50,8 +49,7 @@ struct thread_struct {
 };
 
 #define INIT_THREAD  { \
-	.ksp = sizeof(init_stack) + (unsigned long) &init_stack, \
-	.sr = DEFAULT_PSR_VALUE, \
+	.sp = sizeof(init_stack) + (unsigned long) &init_stack, \
 }
 
 /*

arch/csky/include/asm/ptrace.h

@@ -58,6 +58,16 @@ static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
 	return regs->usp;
 }
 
+static inline unsigned long frame_pointer(struct pt_regs *regs)
+{
+	return regs->regs[4];
+}
+static inline void frame_pointer_set(struct pt_regs *regs,
+				     unsigned long val)
+{
+	regs->regs[4] = val;
+}
+
 extern int regs_query_register_offset(const char *name);
 extern unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs,
 						unsigned int n);

arch/csky/include/asm/thread_info.h

@@ -38,7 +38,13 @@ struct thread_info {
 #define THREAD_SIZE_ORDER (THREAD_SHIFT - PAGE_SHIFT)
 
 #define thread_saved_fp(tsk) \
-	((unsigned long)(((struct switch_stack *)(tsk->thread.ksp))->r8))
+	((unsigned long)(((struct switch_stack *)(tsk->thread.sp))->r8))
+
+#define thread_saved_sp(tsk) \
+	((unsigned long)(tsk->thread.sp))
+
+#define thread_saved_lr(tsk) \
+	((unsigned long)(((struct switch_stack *)(tsk->thread.sp))->r15))
 
 static inline struct thread_info *current_thread_info(void)
 {
@@ -54,10 +60,10 @@ static inline struct thread_info *current_thread_info(void)
 #define TIF_SIGPENDING		0	/* signal pending */
 #define TIF_NOTIFY_RESUME	1       /* callback before returning to user */
 #define TIF_NEED_RESCHED	2	/* rescheduling necessary */
-#define TIF_SYSCALL_TRACE	3	/* syscall trace active */
-#define TIF_SYSCALL_TRACEPOINT	4       /* syscall tracepoint instrumentation */
-#define TIF_SYSCALL_AUDIT	5	/* syscall auditing */
-#define TIF_UPROBE		6	/* uprobe breakpoint or singlestep */
+#define TIF_UPROBE		3	/* uprobe breakpoint or singlestep */
+#define TIF_SYSCALL_TRACE	4	/* syscall trace active */
+#define TIF_SYSCALL_TRACEPOINT	5       /* syscall tracepoint instrumentation */
+#define TIF_SYSCALL_AUDIT	6	/* syscall auditing */
 #define TIF_POLLING_NRFLAG	16	/* poll_idle() is TIF_NEED_RESCHED */
 #define TIF_MEMDIE		18      /* is terminating due to OOM killer */
 #define TIF_RESTORE_SIGMASK	20	/* restore signal mask in do_signal() */

arch/csky/include/asm/uaccess.h

@@ -253,7 +253,7 @@ do {								\
 
 extern int __get_user_bad(void);
 
-#define __copy_user(to, from, n)			\
+#define ___copy_to_user(to, from, n)			\
 do {							\
 	int w0, w1, w2, w3;				\
 	asm volatile(					\
@@ -288,31 +288,34 @@ do {							\
 	"       subi    %0, 4           \n"		\
 	"       br      3b              \n"		\
 	"5:     cmpnei  %0, 0           \n"  /* 1B */   \
-	"       bf      8f              \n"		\
+	"       bf      13f             \n"		\
 	"       ldb     %3, (%2, 0)     \n"		\
 	"6:     stb     %3, (%1, 0)     \n"		\
 	"       addi    %2,  1          \n"		\
 	"       addi    %1,  1          \n"		\
 	"       subi    %0,  1          \n"		\
 	"       br      5b              \n"		\
-	"7:     br      8f              \n"		\
+	"7:     subi	%0,  4          \n"		\
+	"8:     subi	%0,  4          \n"		\
+	"12:    subi	%0,  4          \n"		\
+	"       br      13f             \n"		\
 	".section __ex_table, \"a\"     \n"		\
 	".align   2                     \n"		\
-	".long    2b, 7b                \n"		\
-	".long    9b, 7b                \n"		\
-	".long   10b, 7b                \n"		\
+	".long    2b, 13f               \n"		\
+	".long    4b, 13f               \n"		\
+	".long    6b, 13f               \n"		\
+	".long    9b, 12b               \n"		\
+	".long   10b, 8b                \n"		\
 	".long   11b, 7b                \n"		\
-	".long    4b, 7b                \n"		\
-	".long    6b, 7b                \n"		\
 	".previous                      \n"		\
-	"8:                             \n"		\
+	"13:                            \n"		\
 	: "=r"(n), "=r"(to), "=r"(from), "=r"(w0),	\
 	  "=r"(w1), "=r"(w2), "=r"(w3)			\
 	: "0"(n), "1"(to), "2"(from)			\
 	: "memory");					\
 } while (0)
 
-#define __copy_user_zeroing(to, from, n)		\
+#define ___copy_from_user(to, from, n)			\
 do {							\
 	int tmp;					\
 	int nsave;					\
@@ -355,22 +358,22 @@ do {							\
 	"       addi    %1,  1          \n"		\
 	"       subi    %0,  1          \n"		\
 	"       br      5b              \n"		\
-	"8:     mov     %3, %0          \n"		\
-	"       movi    %4, 0           \n"		\
-	"9:     stb     %4, (%1, 0)     \n"		\
-	"       addi    %1, 1           \n"		\
-	"       subi    %3, 1           \n"		\
-	"       cmpnei  %3, 0           \n"		\
-	"       bt      9b              \n"		\
-	"       br      7f              \n"		\
+	"8:     stw     %3, (%1, 0)     \n"		\
+	"       subi    %0, 4           \n"		\
+	"       bf      7f              \n"		\
+	"9:     subi    %0, 8           \n"		\
+	"       bf      7f              \n"		\
+	"13:    stw     %3, (%1, 8)     \n"		\
+	"       subi    %0, 12          \n"		\
+	"       bf      7f              \n"		\
 	".section __ex_table, \"a\"     \n"		\
 	".align   2                     \n"		\
-	".long    2b, 8b                \n"		\
+	".long    2b, 7f                \n"		\
+	".long    4b, 7f                \n"		\
+	".long    6b, 7f                \n"		\
 	".long   10b, 8b                \n"		\
-	".long   11b, 8b                \n"		\
-	".long   12b, 8b                \n"		\
-	".long    4b, 8b                \n"		\
-	".long    6b, 8b                \n"		\
+	".long   11b, 9b                \n"		\
+	".long   12b,13b                \n"		\
 	".previous                      \n"		\
 	"7:                             \n"		\
 	: "=r"(n), "=r"(to), "=r"(from), "=r"(nsave),	\

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

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));

arch/csky/kernel/dumpstack.c

-// 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);
-}

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

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);

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;
 

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);

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)
 {

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);
 }
 
 /*

arch/csky/kernel/stacktrace.c

 // 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)
-{
-	save_stack_trace_tsk(current, trace);
-}
-EXPORT_SYMBOL_GPL(save_stack_trace);
+#ifdef CONFIG_FRAME_POINTER
 
-void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
+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)
 {
-	unsigned long *fp, *stack_start, *stack_end;
-	unsigned long addr;
-	int skip = trace->skip;
-	int savesched;
-	int graph_idx = 0;
+	unsigned long fp, sp, pc;
 
-	if (tsk == current) {
-		asm volatile("mov %0, r8\n":"=r"(fp));
-		savesched = 1;
+	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 {
-		fp = (unsigned long *)thread_saved_fp(tsk);
-		savesched = 0;
+		/* task blocked in __switch_to */
+		fp = thread_saved_fp(task);
+		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);
+	for (;;) {
+		unsigned long low, high;
+		struct stackframe *frame;
 
-	while (fp > stack_start && fp < stack_end) {
-		unsigned long lpp, fpp;
+		if (unlikely(!__kernel_text_address(pc) || fn(pc, arg)))
+			break;
 
-		fpp = fp[0];
-		lpp = fp[1];
-		if (!__kernel_text_address(lpp))
+		/* Validate frame pointer */
+		low = sp;
+		high = ALIGN(sp, THREAD_SIZE);
+		if (unlikely(fp < low || fp > high || fp & 0x3))
 			break;
-		else
-			lpp = ftrace_graph_ret_addr(tsk, &graph_idx, lpp, NULL);
+		/* 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));
+	}
+}
+
+#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 sp, pc;
+	unsigned long *ksp;
 
-		if (savesched || !in_sched_functions(lpp)) {
-			if (skip) {
-				skip--;
+	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 {
-				trace->entries[trace->nr_entries++] = lpp;
-				if (trace->nr_entries >= trace->max_entries)
+		/* task blocked in __switch_to */
+		sp = thread_saved_sp(task);
+		pc = thread_saved_lr(task);
+	}
+
+	if (unlikely(sp & 0x3))
+		return;
+
+	ksp = (unsigned long *)sp;
+	while (!kstack_end(ksp)) {
+		if (__kernel_text_address(pc) && unlikely(fn(pc, arg)))
 			break;
+		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;
 	}
-		fp = (unsigned long *)fpp;
+	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 */

arch/csky/lib/usercopy.c

@@ -7,10 +7,7 @@
 unsigned long raw_copy_from_user(void *to, const void *from,
 			unsigned long n)
 {
-	if (access_ok(from, n))
-		__copy_user_zeroing(to, from, n);
-	else
-		memset(to, 0, n);
+	___copy_from_user(to, from, n);
 	return n;
 }
 EXPORT_SYMBOL(raw_copy_from_user);
@@ -18,8 +15,7 @@ EXPORT_SYMBOL(raw_copy_from_user);
 unsigned long raw_copy_to_user(void *to, const void *from,
 			unsigned long n)
 {
-	if (access_ok(to, n))
-		__copy_user(to, from, n);
+	___copy_to_user(to, from, n);
 	return n;
 }
 EXPORT_SYMBOL(raw_copy_to_user);