v4.19.13 snapshot.
diff --git a/arch/nds32/kernel/ftrace.c b/arch/nds32/kernel/ftrace.c
new file mode 100644
index 0000000..8a41372
--- /dev/null
+++ b/arch/nds32/kernel/ftrace.c
@@ -0,0 +1,295 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/ftrace.h>
+#include <linux/uaccess.h>
+#include <asm/cacheflush.h>
+
+#ifndef CONFIG_DYNAMIC_FTRACE
+extern void (*ftrace_trace_function)(unsigned long, unsigned long,
+ struct ftrace_ops*, struct pt_regs*);
+extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace);
+extern void ftrace_graph_caller(void);
+
+noinline void __naked ftrace_stub(unsigned long ip, unsigned long parent_ip,
+ struct ftrace_ops *op, struct pt_regs *regs)
+{
+ __asm__ (""); /* avoid to optimize as pure function */
+}
+
+noinline void _mcount(unsigned long parent_ip)
+{
+ /* save all state by the compiler prologue */
+
+ unsigned long ip = (unsigned long)__builtin_return_address(0);
+
+ if (ftrace_trace_function != ftrace_stub)
+ ftrace_trace_function(ip - MCOUNT_INSN_SIZE, parent_ip,
+ NULL, NULL);
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+ if (ftrace_graph_return != (trace_func_graph_ret_t)ftrace_stub
+ || ftrace_graph_entry != ftrace_graph_entry_stub)
+ ftrace_graph_caller();
+#endif
+
+ /* restore all state by the compiler epilogue */
+}
+EXPORT_SYMBOL(_mcount);
+
+#else /* CONFIG_DYNAMIC_FTRACE */
+
+noinline void __naked ftrace_stub(unsigned long ip, unsigned long parent_ip,
+ struct ftrace_ops *op, struct pt_regs *regs)
+{
+ __asm__ (""); /* avoid to optimize as pure function */
+}
+
+noinline void __naked _mcount(unsigned long parent_ip)
+{
+ __asm__ (""); /* avoid to optimize as pure function */
+}
+EXPORT_SYMBOL(_mcount);
+
+#define XSTR(s) STR(s)
+#define STR(s) #s
+void _ftrace_caller(unsigned long parent_ip)
+{
+ /* save all state needed by the compiler prologue */
+
+ /*
+ * prepare arguments for real tracing function
+ * first arg : __builtin_return_address(0) - MCOUNT_INSN_SIZE
+ * second arg : parent_ip
+ */
+ __asm__ __volatile__ (
+ "move $r1, %0 \n\t"
+ "addi $r0, %1, #-" XSTR(MCOUNT_INSN_SIZE) "\n\t"
+ :
+ : "r" (parent_ip), "r" (__builtin_return_address(0)));
+
+ /* a placeholder for the call to a real tracing function */
+ __asm__ __volatile__ (
+ "ftrace_call: \n\t"
+ "nop \n\t"
+ "nop \n\t"
+ "nop \n\t");
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+ /* a placeholder for the call to ftrace_graph_caller */
+ __asm__ __volatile__ (
+ "ftrace_graph_call: \n\t"
+ "nop \n\t"
+ "nop \n\t"
+ "nop \n\t");
+#endif
+ /* restore all state needed by the compiler epilogue */
+}
+
+int __init ftrace_dyn_arch_init(void)
+{
+ return 0;
+}
+
+int ftrace_arch_code_modify_prepare(void)
+{
+ set_all_modules_text_rw();
+ return 0;
+}
+
+int ftrace_arch_code_modify_post_process(void)
+{
+ set_all_modules_text_ro();
+ return 0;
+}
+
+static unsigned long gen_sethi_insn(unsigned long addr)
+{
+ unsigned long opcode = 0x46000000;
+ unsigned long imm = addr >> 12;
+ unsigned long rt_num = 0xf << 20;
+
+ return ENDIAN_CONVERT(opcode | rt_num | imm);
+}
+
+static unsigned long gen_ori_insn(unsigned long addr)
+{
+ unsigned long opcode = 0x58000000;
+ unsigned long imm = addr & 0x0000fff;
+ unsigned long rt_num = 0xf << 20;
+ unsigned long ra_num = 0xf << 15;
+
+ return ENDIAN_CONVERT(opcode | rt_num | ra_num | imm);
+}
+
+static unsigned long gen_jral_insn(unsigned long addr)
+{
+ unsigned long opcode = 0x4a000001;
+ unsigned long rt_num = 0x1e << 20;
+ unsigned long rb_num = 0xf << 10;
+
+ return ENDIAN_CONVERT(opcode | rt_num | rb_num);
+}
+
+static void ftrace_gen_call_insn(unsigned long *call_insns,
+ unsigned long addr)
+{
+ call_insns[0] = gen_sethi_insn(addr); /* sethi $r15, imm20u */
+ call_insns[1] = gen_ori_insn(addr); /* ori $r15, $r15, imm15u */
+ call_insns[2] = gen_jral_insn(addr); /* jral $lp, $r15 */
+}
+
+static int __ftrace_modify_code(unsigned long pc, unsigned long *old_insn,
+ unsigned long *new_insn, bool validate)
+{
+ unsigned long orig_insn[3];
+
+ if (validate) {
+ if (probe_kernel_read(orig_insn, (void *)pc, MCOUNT_INSN_SIZE))
+ return -EFAULT;
+ if (memcmp(orig_insn, old_insn, MCOUNT_INSN_SIZE))
+ return -EINVAL;
+ }
+
+ if (probe_kernel_write((void *)pc, new_insn, MCOUNT_INSN_SIZE))
+ return -EPERM;
+
+ return 0;
+}
+
+static int ftrace_modify_code(unsigned long pc, unsigned long *old_insn,
+ unsigned long *new_insn, bool validate)
+{
+ int ret;
+
+ ret = __ftrace_modify_code(pc, old_insn, new_insn, validate);
+ if (ret)
+ return ret;
+
+ flush_icache_range(pc, pc + MCOUNT_INSN_SIZE);
+
+ return ret;
+}
+
+int ftrace_update_ftrace_func(ftrace_func_t func)
+{
+ unsigned long pc = (unsigned long)&ftrace_call;
+ unsigned long old_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
+ unsigned long new_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
+
+ if (func != ftrace_stub)
+ ftrace_gen_call_insn(new_insn, (unsigned long)func);
+
+ return ftrace_modify_code(pc, old_insn, new_insn, false);
+}
+
+int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
+{
+ unsigned long pc = rec->ip;
+ unsigned long nop_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
+ unsigned long call_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
+
+ ftrace_gen_call_insn(call_insn, addr);
+
+ return ftrace_modify_code(pc, nop_insn, call_insn, true);
+}
+
+int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
+ unsigned long addr)
+{
+ unsigned long pc = rec->ip;
+ unsigned long nop_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
+ unsigned long call_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
+
+ ftrace_gen_call_insn(call_insn, addr);
+
+ return ftrace_modify_code(pc, call_insn, nop_insn, true);
+}
+#endif /* CONFIG_DYNAMIC_FTRACE */
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
+ unsigned long frame_pointer)
+{
+ unsigned long return_hooker = (unsigned long)&return_to_handler;
+ unsigned long old;
+
+ if (unlikely(atomic_read(¤t->tracing_graph_pause)))
+ return;
+
+ old = *parent;
+
+ if (!function_graph_enter(old, self_addr, frame_pointer, NULL))
+ *parent = return_hooker;
+}
+
+noinline void ftrace_graph_caller(void)
+{
+ unsigned long *parent_ip =
+ (unsigned long *)(__builtin_frame_address(2) - 4);
+
+ unsigned long selfpc =
+ (unsigned long)(__builtin_return_address(1) - MCOUNT_INSN_SIZE);
+
+ unsigned long frame_pointer =
+ (unsigned long)__builtin_frame_address(3);
+
+ prepare_ftrace_return(parent_ip, selfpc, frame_pointer);
+}
+
+extern unsigned long ftrace_return_to_handler(unsigned long frame_pointer);
+void __naked return_to_handler(void)
+{
+ __asm__ __volatile__ (
+ /* save state needed by the ABI */
+ "smw.adm $r0,[$sp],$r1,#0x0 \n\t"
+
+ /* get original return address */
+ "move $r0, $fp \n\t"
+ "bal ftrace_return_to_handler\n\t"
+ "move $lp, $r0 \n\t"
+
+ /* restore state nedded by the ABI */
+ "lmw.bim $r0,[$sp],$r1,#0x0 \n\t");
+}
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+extern unsigned long ftrace_graph_call;
+
+static int ftrace_modify_graph_caller(bool enable)
+{
+ unsigned long pc = (unsigned long)&ftrace_graph_call;
+ unsigned long nop_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
+ unsigned long call_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
+
+ ftrace_gen_call_insn(call_insn, (unsigned long)ftrace_graph_caller);
+
+ if (enable)
+ return ftrace_modify_code(pc, nop_insn, call_insn, true);
+ else
+ return ftrace_modify_code(pc, call_insn, nop_insn, true);
+}
+
+int ftrace_enable_ftrace_graph_caller(void)
+{
+ return ftrace_modify_graph_caller(true);
+}
+
+int ftrace_disable_ftrace_graph_caller(void)
+{
+ return ftrace_modify_graph_caller(false);
+}
+#endif /* CONFIG_DYNAMIC_FTRACE */
+
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+
+
+#ifdef CONFIG_TRACE_IRQFLAGS
+noinline void __trace_hardirqs_off(void)
+{
+ trace_hardirqs_off();
+}
+noinline void __trace_hardirqs_on(void)
+{
+ trace_hardirqs_on();
+}
+#endif /* CONFIG_TRACE_IRQFLAGS */