Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/csky/kernel/ftrace.c b/arch/csky/kernel/ftrace.c
new file mode 100644
index 0000000..44f4880
--- /dev/null
+++ b/arch/csky/kernel/ftrace.c
@@ -0,0 +1,194 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+
+#include <linux/ftrace.h>
+#include <linux/uaccess.h>
+#include <asm/cacheflush.h>
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+
+#define NOP 0x4000
+#define NOP32_HI 0xc400
+#define NOP32_LO 0x4820
+#define PUSH_LR 0x14d0
+#define MOVIH_LINK 0xea3a
+#define ORI_LINK 0xef5a
+#define JSR_LINK 0xe8fa
+#define BSR_LINK 0xe000
+
+/*
+ * Gcc-csky with -pg will insert stub in function prologue:
+ * push lr
+ * jbsr _mcount
+ * nop32
+ * nop32
+ *
+ * If the (callee - current_pc) is less then 64MB, we'll use bsr:
+ * push lr
+ * bsr _mcount
+ * nop32
+ * nop32
+ * else we'll use (movih + ori + jsr):
+ * push lr
+ * movih r26, ...
+ * ori r26, ...
+ * jsr r26
+ *
+ * (r26 is our reserved link-reg)
+ *
+ */
+static inline void make_jbsr(unsigned long callee, unsigned long pc,
+ uint16_t *call, bool nolr)
+{
+ long offset;
+
+ call[0] = nolr ? NOP : PUSH_LR;
+
+ offset = (long) callee - (long) pc;
+
+ if (unlikely(offset < -67108864 || offset > 67108864)) {
+ call[1] = MOVIH_LINK;
+ call[2] = callee >> 16;
+ call[3] = ORI_LINK;
+ call[4] = callee & 0xffff;
+ call[5] = JSR_LINK;
+ call[6] = 0;
+ } else {
+ offset = offset >> 1;
+
+ call[1] = BSR_LINK |
+ ((uint16_t)((unsigned long) offset >> 16) & 0x3ff);
+ call[2] = (uint16_t)((unsigned long) offset & 0xffff);
+ call[3] = call[5] = NOP32_HI;
+ call[4] = call[6] = NOP32_LO;
+ }
+}
+
+static uint16_t nops[7] = {NOP, NOP32_HI, NOP32_LO, NOP32_HI, NOP32_LO,
+ NOP32_HI, NOP32_LO};
+static int ftrace_check_current_nop(unsigned long hook)
+{
+ uint16_t olds[7];
+ unsigned long hook_pos = hook - 2;
+
+ if (probe_kernel_read((void *)olds, (void *)hook_pos, sizeof(nops)))
+ return -EFAULT;
+
+ if (memcmp((void *)nops, (void *)olds, sizeof(nops))) {
+ pr_err("%p: nop but get (%04x %04x %04x %04x %04x %04x %04x)\n",
+ (void *)hook_pos,
+ olds[0], olds[1], olds[2], olds[3], olds[4], olds[5],
+ olds[6]);
+
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int ftrace_modify_code(unsigned long hook, unsigned long target,
+ bool enable, bool nolr)
+{
+ uint16_t call[7];
+
+ unsigned long hook_pos = hook - 2;
+ int ret = 0;
+
+ make_jbsr(target, hook, call, nolr);
+
+ ret = probe_kernel_write((void *)hook_pos, enable ? call : nops,
+ sizeof(nops));
+ if (ret)
+ return -EPERM;
+
+ flush_icache_range(hook_pos, hook_pos + MCOUNT_INSN_SIZE);
+
+ return 0;
+}
+
+int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
+{
+ int ret = ftrace_check_current_nop(rec->ip);
+
+ if (ret)
+ return ret;
+
+ return ftrace_modify_code(rec->ip, addr, true, false);
+}
+
+int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
+ unsigned long addr)
+{
+ return ftrace_modify_code(rec->ip, addr, false, false);
+}
+
+int ftrace_update_ftrace_func(ftrace_func_t func)
+{
+ int ret = ftrace_modify_code((unsigned long)&ftrace_call,
+ (unsigned long)func, true, true);
+ return ret;
+}
+
+int __init ftrace_dyn_arch_init(void)
+{
+ return 0;
+}
+#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,
+ *(unsigned long *)frame_pointer, parent)) {
+ /*
+ * For csky-gcc function has sub-call:
+ * subi sp, sp, 8
+ * stw r8, (sp, 0)
+ * mov r8, sp
+ * st.w r15, (sp, 0x4)
+ * push r15
+ * jl _mcount
+ * We only need set *parent for resume
+ *
+ * For csky-gcc function has no sub-call:
+ * subi sp, sp, 4
+ * stw r8, (sp, 0)
+ * mov r8, sp
+ * push r15
+ * jl _mcount
+ * We need set *parent and *(frame_pointer + 4) for resume,
+ * because lr is resumed twice.
+ */
+ *parent = return_hooker;
+ frame_pointer += 4;
+ if (*(unsigned long *)frame_pointer == old)
+ *(unsigned long *)frame_pointer = return_hooker;
+ }
+}
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+int ftrace_enable_ftrace_graph_caller(void)
+{
+ return ftrace_modify_code((unsigned long)&ftrace_graph_call,
+ (unsigned long)&ftrace_graph_caller, true, true);
+}
+
+int ftrace_disable_ftrace_graph_caller(void)
+{
+ return ftrace_modify_code((unsigned long)&ftrace_graph_call,
+ (unsigned long)&ftrace_graph_caller, false, true);
+}
+#endif /* CONFIG_DYNAMIC_FTRACE */
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+
+/* _mcount is defined in abi's mcount.S */
+EXPORT_SYMBOL(_mcount);