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authorZong Li <zong@andestech.com>2018-08-15 10:45:59 +0800
committerGreentime Hu <greentime@andestech.com>2018-09-04 14:45:17 +0800
commita18082575c664847d36c6ca030b09ce8d93aec2f (patch)
tree96070f10fadd478d6f644d639b899d9bb9311650 /arch/nds32/kernel
parent487913ab18c215b06611c4c91c7e905fc0960eb8 (diff)
nds32/ftrace: Support static function tracer
This patch support the static function tracer. On nds32 ABI, we need to always push return address to stack for __builtin_return_address can work correctly, otherwise, it will get the wrong value of $lp at leaf function. Signed-off-by: Zong Li <zong@andestech.com> Acked-by: Greentime Hu <greentime@andestech.com> Signed-off-by: Greentime Hu <greentime@andestech.com>
Diffstat (limited to 'arch/nds32/kernel')
-rw-r--r--arch/nds32/kernel/Makefile6
-rw-r--r--arch/nds32/kernel/ftrace.c28
2 files changed, 34 insertions, 0 deletions
diff --git a/arch/nds32/kernel/Makefile b/arch/nds32/kernel/Makefile
index 42792743e8b9..27cded39fa66 100644
--- a/arch/nds32/kernel/Makefile
+++ b/arch/nds32/kernel/Makefile
@@ -21,3 +21,9 @@ extra-y := head.o vmlinux.lds
obj-y += vdso/
+
+obj-$(CONFIG_FUNCTION_TRACER) += ftrace.o
+
+ifdef CONFIG_FUNCTION_TRACER
+CFLAGS_REMOVE_ftrace.o = $(CC_FLAGS_FTRACE)
+endif
diff --git a/arch/nds32/kernel/ftrace.c b/arch/nds32/kernel/ftrace.c
new file mode 100644
index 000000000000..563f64c070b3
--- /dev/null
+++ b/arch/nds32/kernel/ftrace.c
@@ -0,0 +1,28 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/ftrace.h>
+#include <linux/uaccess.h>
+#include <asm/cacheflush.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__ (""); /* 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);
+
+ /* restore all state by the compiler epilogue */
+}
+EXPORT_SYMBOL(_mcount);