csky: basic ftrace supported

When gcc with -pg, it'll add _mcount stub in every function. We need
implement the _mcount in kernel and ftrace depends on stackstrace.

To do: call-graph, dynamic ftrace

Signed-off-by: Guo Ren <ren_guo@c-sky.com>

diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig
index 65804d1628a8a15a2a71cb310481e2e627a6492e..0b9a290c015748144cd5ca7a530b5de43c849094 100644 (file)
--- a/arch/csky/Kconfig
+++ b/arch/csky/Kconfig
@@ -29,6 +29,7 @@ config CSKY
        select GENERIC_SCHED_CLOCK
        select GENERIC_SMP_IDLE_THREAD
        select HAVE_ARCH_TRACEHOOK
+       select HAVE_FUNCTION_TRACER
        select HAVE_GENERIC_DMA_COHERENT
        select HAVE_KERNEL_GZIP
        select HAVE_KERNEL_LZO

diff --git a/arch/csky/abiv2/Makefile b/arch/csky/abiv2/Makefile
index 069ca7276b99ac1a13c168d835d5db2be0c204ad..b1d44f6fbcbdd90841bb5fffaca498476ead8f5e 100644 (file)
--- a/arch/csky/abiv2/Makefile
+++ b/arch/csky/abiv2/Makefile
@@ -8,3 +8,4 @@ obj-y                           += strcmp.o
 obj-y                          += strcpy.o
 obj-y                          += strlen.o
 obj-y                          += strksyms.o
+obj-$(CONFIG_FUNCTION_TRACER)  += mcount.o

diff --git a/arch/csky/abiv2/mcount.S b/arch/csky/abiv2/mcount.S
new file mode 100644 (file)
index 0000000..73377d5
--- /dev/null
+++ b/arch/csky/abiv2/mcount.S
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+
+#include <linux/linkage.h>
+
+ENTRY (_mcount)
+       subi    sp, 20
+       stw     a0, (sp, 0)
+       stw     a1, (sp, 4)
+       stw     a2, (sp, 8)
+       stw     a3, (sp, 12)
+       stw     lr, (sp, 16)
+       mov     a1, lr
+       ldw     a0, (sp, 20)
+       jsri    csky_mcount
+       ldw     a0, (sp, 0)
+       ldw     a1, (sp, 4)
+       ldw     a2, (sp, 8)
+       ldw     a3, (sp, 12)
+       ldw     t1, (sp, 16)
+       ldw     lr, (sp, 20)
+       addi    sp, 24
+       jmp     t1
+END (_mcount)

diff --git a/arch/csky/include/asm/ftrace.h b/arch/csky/include/asm/ftrace.h
new file mode 100644 (file)
index 0000000..1d22a17
--- /dev/null
+++ b/arch/csky/include/asm/ftrace.h
@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+
+#ifndef __ASM_CSKY_FTRACE_H
+#define __ASM_CSKY_FTRACE_H
+
+extern void _mcount(unsigned long from_pc);
+
+#endif /* __ASM_CSKY_FTRACE_H */

diff --git a/arch/csky/kernel/Makefile b/arch/csky/kernel/Makefile
index ba5ca486f0f60e1f3b48117a9611b86c6afeefd3..3c0e2d15d4e001ae14321abb142d54cae412595c 100644 (file)
--- a/arch/csky/kernel/Makefile
+++ b/arch/csky/kernel/Makefile
@@ -6,4 +6,9 @@ obj-y += process.o cpu-probe.o ptrace.o dumpstack.o
 
 obj-$(CONFIG_MODULES)                  += module.o
 obj-$(CONFIG_SMP)                      += smp.o
+obj-$(CONFIG_FUNCTION_TRACER)          += ftrace.o
 obj-$(CONFIG_STACKTRACE)               += stacktrace.o
+
+ifdef CONFIG_FUNCTION_TRACER
+CFLAGS_REMOVE_ftrace.o = $(CC_FLAGS_FTRACE)
+endif

diff --git a/arch/csky/kernel/ftrace.c b/arch/csky/kernel/ftrace.c
new file mode 100644 (file)
index 0000000..ad054f7
--- /dev/null
+++ b/arch/csky/kernel/ftrace.c
@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+
+#include <linux/ftrace.h>
+#include <linux/uaccess.h>
+
+extern void (*ftrace_trace_function)(unsigned long, unsigned long,
+                                    struct ftrace_ops*, struct pt_regs*);
+
+
+noinline void __naked ftrace_stub(unsigned long ip, unsigned long parent_ip,
+                                 struct ftrace_ops *op, struct pt_regs *regs)
+{
+       asm volatile ("\n");
+}
+
+noinline void csky_mcount(unsigned long from_pc, unsigned long self_pc)
+{
+       if (ftrace_trace_function != ftrace_stub)
+               ftrace_trace_function(self_pc, from_pc, NULL, NULL);
+}
+
+/* _mcount is defined in abi's mcount.S */
+EXPORT_SYMBOL(_mcount);