ARM: ftrace: function graph tracer support (376cfa87) · Commits · 戴 / test

arch/arm/kernel/Makefile

+2 −1

Original line number	Diff line number	Diff line
		@@ -5,7 +5,7 @@
		CPPFLAGS_vmlinux.lds := -DTEXT_OFFSET=$(TEXT_OFFSET)
		AFLAGS_head.o := -DTEXT_OFFSET=$(TEXT_OFFSET)

		ifdef CONFIG_DYNAMIC_FTRACE
		ifdef CONFIG_FUNCTION_TRACER
		CFLAGS_REMOVE_ftrace.o = -pg
		endif

		@@ -33,6 +33,7 @@ obj-$(CONFIG_SMP) += smp.o
		obj-$(CONFIG_HAVE_ARM_SCU) += smp_scu.o
		obj-$(CONFIG_HAVE_ARM_TWD) += smp_twd.o
		obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o
		obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o
		obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o
		obj-$(CONFIG_KPROBES) += kprobes.o kprobes-decode.o
		obj-$(CONFIG_ATAGS_PROC) += atags.o

+46 −0

Original line number	Diff line number	Diff line
		@@ -148,6 +148,20 @@ ENDPROC(ret_from_fork)
		adr r0, .Lftrace_stub
		cmp r0, r2
		bne 1f

		#ifdef CONFIG_FUNCTION_GRAPH_TRACER
		ldr r1, =ftrace_graph_return
		ldr r2, [r1]
		cmp r0, r2
		bne ftrace_graph_caller\suffix

		ldr r1, =ftrace_graph_entry
		ldr r2, [r1]
		ldr r0, =ftrace_graph_entry_stub
		cmp r0, r2
		bne ftrace_graph_caller\suffix
		#endif

		mcount_exit

		1: mcount_get_lr r1 @ lr of instrumented func
		@@ -172,6 +186,15 @@ ftrace_call\suffix:
		mcount_exit
		.endm

		.macro __ftrace_graph_caller
		sub r0, fp, #4 @ &lr of instrumented routine (&parent)
		mov r1, lr @ instrumented routine (func)
		sub r1, r1, #MCOUNT_INSN_SIZE
		mov r2, fp @ frame pointer
		bl prepare_ftrace_return
		mcount_exit
		.endm

		#ifdef CONFIG_OLD_MCOUNT
		/*
		* mcount
		@@ -206,6 +229,12 @@ ENTRY(ftrace_caller_old)
		ENDPROC(ftrace_caller_old)
		#endif

		#ifdef CONFIG_FUNCTION_GRAPH_TRACER
		ENTRY(ftrace_graph_caller_old)
		__ftrace_graph_caller
		ENDPROC(ftrace_graph_caller_old)
		#endif

		.purgem mcount_enter
		.purgem mcount_get_lr
		.purgem mcount_exit
		@@ -244,10 +273,27 @@ ENTRY(ftrace_caller)
		ENDPROC(ftrace_caller)
		#endif

		#ifdef CONFIG_FUNCTION_GRAPH_TRACER
		ENTRY(ftrace_graph_caller)
		__ftrace_graph_caller
		ENDPROC(ftrace_graph_caller)
		#endif

		.purgem mcount_enter
		.purgem mcount_get_lr
		.purgem mcount_exit

		#ifdef CONFIG_FUNCTION_GRAPH_TRACER
		.globl return_to_handler
		return_to_handler:
		stmdb sp!, {r0-r3}
		mov r0, fp @ frame pointer
		bl ftrace_return_to_handler
		mov lr, r0 @ r0 has real ret addr
		ldmia sp!, {r0-r3}
		mov pc, lr
		#endif

		ENTRY(ftrace_stub)
		.Lftrace_stub:
		mov pc, lr

+34 −0

Original line number	Diff line number	Diff line
		@@ -24,6 +24,7 @@
		#define NOP 0xe8bd4000 /* pop {lr} */
		#endif

		#ifdef CONFIG_DYNAMIC_FTRACE
		#ifdef CONFIG_OLD_MCOUNT
		#define OLD_MCOUNT_ADDR ((unsigned long) mcount)
		#define OLD_FTRACE_ADDR ((unsigned long) ftrace_caller_old)
		@@ -193,3 +194,36 @@ int __init ftrace_dyn_arch_init(void *data)

		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;
		struct ftrace_graph_ent trace;
		unsigned long old;
		int err;

		if (unlikely(atomic_read(&current->tracing_graph_pause)))
		return;

		old = *parent;
		*parent = return_hooker;

		err = ftrace_push_return_trace(old, self_addr, &trace.depth,
		frame_pointer);
		if (err == -EBUSY) {
		*parent = old;
		return;
		}

		trace.func = self_addr;

		/* Only trace if the calling function expects to */
		if (!ftrace_graph_entry(&trace)) {
		current->curr_ret_stack--;
		*parent = old;
		}
		}
		#endif /* CONFIG_FUNCTION_GRAPH_TRACER */