On Wed, 15 Aug 2018 17:35:18 +0800 Zong Li <[email protected]> wrote:
> 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 <[email protected]> > --- > arch/nds32/Kconfig | 1 + > arch/nds32/Makefile | 4 ++++ > arch/nds32/include/asm/ftrace.h | 20 ++++++++++++++++++++ > arch/nds32/kernel/Makefile | 6 ++++++ > arch/nds32/kernel/ftrace.c | 28 ++++++++++++++++++++++++++++ > 5 files changed, 59 insertions(+) > create mode 100644 arch/nds32/include/asm/ftrace.h > create mode 100644 arch/nds32/kernel/ftrace.c > > diff --git a/arch/nds32/Kconfig b/arch/nds32/Kconfig > index 34f7222..af30e1a 100644 > --- a/arch/nds32/Kconfig > +++ b/arch/nds32/Kconfig > @@ -40,6 +40,7 @@ config NDS32 > select NO_IOPORT_MAP > select RTC_LIB > select THREAD_INFO_IN_TASK > + select HAVE_FUNCTION_TRACER > help > Andes(nds32) Linux support. > > diff --git a/arch/nds32/Makefile b/arch/nds32/Makefile > index 031c676..3ca8172 100644 > --- a/arch/nds32/Makefile > +++ b/arch/nds32/Makefile > @@ -5,6 +5,10 @@ KBUILD_DEFCONFIG := defconfig > > comma = , > > +ifdef CONFIG_FUNCTION_TRACER > +arch-y += -malways-save-lp -mno-relax > +endif > + > KBUILD_CFLAGS += $(call cc-option, -mno-sched-prolog-epilog) > KBUILD_CFLAGS += -mcmodel=large > > diff --git a/arch/nds32/include/asm/ftrace.h b/arch/nds32/include/asm/ftrace.h > new file mode 100644 > index 0000000..bac7657 > --- /dev/null > +++ b/arch/nds32/include/asm/ftrace.h > @@ -0,0 +1,20 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > + > +#ifndef __ASM_NDS32_FTRACE_H > +#define __ASM_NDS32_FTRACE_H > + > +#ifdef CONFIG_FUNCTION_TRACER > + > +#define HAVE_FUNCTION_GRAPH_FP_TEST > + > +#define MCOUNT_ADDR ((unsigned long)(_mcount)) > +/* mcount call is composed of three instructions: > + * sethi + ori + jral > + */ > +#define MCOUNT_INSN_SIZE 12 > + > +extern void _mcount(unsigned long parent_ip); > + > +#endif /* CONFIG_FUNCTION_TRACER */ > + > +#endif /* __ASM_NDS32_FTRACE_H */ > diff --git a/arch/nds32/kernel/Makefile b/arch/nds32/kernel/Makefile > index 4279274..27cded3 100644 > --- a/arch/nds32/kernel/Makefile > +++ b/arch/nds32/kernel/Makefile > @@ -21,3 +21,9 @@ extra-y := head.o vmlinux.lds > > > obj-y += vdso/ > + > +obj-$(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 0000000..563f64c > --- /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) > +{ Wow! The NDS32 arch allows for _mcount to be a C function! That's nice :-) -- Steve > + /* 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);
