ARM: 8788/1: ftrace: remove old mcount support (d3c61619) · Commits · 戴 / test

arch/arm/Kconfig.debug

+0 −5

Original line number	Diff line number	Diff line
		@@ -70,11 +70,6 @@ config ARM_UNWIND
		the performance is not affected. Currently, this feature
		only works with EABI compilers. If unsure say Y.

		config OLD_MCOUNT
		bool
		depends on FUNCTION_TRACER && FRAME_POINTER
		default y

		config DEBUG_USER
		bool "Verbose user fault messages"
		help

arch/arm/include/asm/ftrace.h

+0 −3

Original line number	Diff line number	Diff line
		@@ -16,9 +16,6 @@ extern void __gnu_mcount_nc(void);

		#ifdef CONFIG_DYNAMIC_FTRACE
		struct dyn_arch_ftrace {
		#ifdef CONFIG_OLD_MCOUNT
		bool old_mcount;
		#endif
		};

		static inline unsigned long ftrace_call_adjust(unsigned long addr)

arch/arm/kernel/armksyms.c

+0 −3

Original line number	Diff line number	Diff line
		@@ -167,9 +167,6 @@ EXPORT_SYMBOL(_find_next_bit_be);
		#endif

		#ifdef CONFIG_FUNCTION_TRACER
		#ifdef CONFIG_OLD_MCOUNT
		EXPORT_SYMBOL(mcount);
		#endif
		EXPORT_SYMBOL(__gnu_mcount_nc);
		#endif

arch/arm/kernel/entry-ftrace.S

+4 −71

Original line number	Diff line number	Diff line
		@@ -15,23 +15,8 @@
		* start of every function. In mcount, apart from the function's address (in
		* lr), we need to get hold of the function's caller's address.
		*
		* Older GCCs (pre-4.4) inserted a call to a routine called mcount like this:
		*
		* bl mcount
		*
		* These versions have the limitation that in order for the mcount routine to
		* be able to determine the function's caller's address, an APCS-style frame
		* pointer (which is set up with something like the code below) is required.
		*
		* mov ip, sp
		* push {fp, ip, lr, pc}
		* sub fp, ip, #4
		*
		* With EABI, these frame pointers are not available unless -mapcs-frame is
		* specified, and if building as Thumb-2, not even then.
		*
		* Newer GCCs (4.4+) solve this problem by introducing a new version of mcount,
		* with call sites like:
		* Newer GCCs (4.4+) solve this problem by using a version of mcount with call
		* sites like:
		*
		* push {lr}
		* bl __gnu_mcount_nc
		@@ -46,17 +31,10 @@
		* allows it to be clobbered in subroutines and doesn't use it to hold
		* parameters.)
		*
		* When using dynamic ftrace, we patch out the mcount call by a "mov r0, r0"
		* for the mcount case, and a "pop {lr}" for the __gnu_mcount_nc case (see
		* arch/arm/kernel/ftrace.c).
		* When using dynamic ftrace, we patch out the mcount call by a "pop {lr}"
		* instead of the __gnu_mcount_nc call (see arch/arm/kernel/ftrace.c).
		*/

		#ifndef CONFIG_OLD_MCOUNT
		#if (__GNUC__ < 4 \|\| (__GNUC__ == 4 && __GNUC_MINOR__ < 4))
		#error Ftrace requires CONFIG_FRAME_POINTER=y with GCC older than 4.4.0.
		#endif
		#endif

		.macro mcount_adjust_addr rd, rn
		bic \rd, \rn, #1 @ clear the Thumb bit if present
		sub \rd, \rd, #MCOUNT_INSN_SIZE
		@@ -209,51 +187,6 @@ ftrace_graph_call\suffix:
		mcount_exit
		.endm

		#ifdef CONFIG_OLD_MCOUNT
		/*
		* mcount
		*/

		.macro mcount_enter
		stmdb sp!, {r0-r3, lr}
		.endm

		.macro mcount_get_lr reg
		ldr \reg, [fp, #-4]
		.endm

		.macro mcount_exit
		ldr lr, [fp, #-4]
		ldmia sp!, {r0-r3, pc}
		.endm

		ENTRY(mcount)
		#ifdef CONFIG_DYNAMIC_FTRACE
		stmdb sp!, {lr}
		ldr lr, [fp, #-4]
		ldmia sp!, {pc}
		#else
		__mcount _old
		#endif
		ENDPROC(mcount)

		#ifdef CONFIG_DYNAMIC_FTRACE
		ENTRY(ftrace_caller_old)
		__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
		#endif

		/*
		* __gnu_mcount_nc
		*/

arch/arm/kernel/ftrace.c

+0 −51

Original line number	Diff line number	Diff line
		@@ -47,30 +47,6 @@ void arch_ftrace_update_code(int command)
		stop_machine(__ftrace_modify_code, &command, NULL);
		}

		#ifdef CONFIG_OLD_MCOUNT
		#define OLD_MCOUNT_ADDR ((unsigned long) mcount)
		#define OLD_FTRACE_ADDR ((unsigned long) ftrace_caller_old)

		#define OLD_NOP 0xe1a00000 /* mov r0, r0 */

		static unsigned long ftrace_nop_replace(struct dyn_ftrace *rec)
		{
		return rec->arch.old_mcount ? OLD_NOP : NOP;
		}

		static unsigned long adjust_address(struct dyn_ftrace *rec, unsigned long addr)
		{
		if (!rec->arch.old_mcount)
		return addr;

		if (addr == MCOUNT_ADDR)
		addr = OLD_MCOUNT_ADDR;
		else if (addr == FTRACE_ADDR)
		addr = OLD_FTRACE_ADDR;

		return addr;
		}
		#else
		static unsigned long ftrace_nop_replace(struct dyn_ftrace *rec)
		{
		return NOP;
		@@ -80,7 +56,6 @@ static unsigned long adjust_address(struct dyn_ftrace *rec, unsigned long addr)
		{
		return addr;
		}
		#endif

		int ftrace_arch_code_modify_prepare(void)
		{
		@@ -150,15 +125,6 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
		}
		#endif

		#ifdef CONFIG_OLD_MCOUNT
		if (!ret) {
		pc = (unsigned long)&ftrace_call_old;
		new = ftrace_call_replace(pc, (unsigned long)func);

		ret = ftrace_modify_code(pc, 0, new, false);
		}
		#endif

		return ret;
		}

		@@ -203,16 +169,6 @@ int ftrace_make_nop(struct module *mod,
		new = ftrace_nop_replace(rec);
		ret = ftrace_modify_code(ip, old, new, true);

		#ifdef CONFIG_OLD_MCOUNT
		if (ret == -EINVAL && addr == MCOUNT_ADDR) {
		rec->arch.old_mcount = true;

		old = ftrace_call_replace(ip, adjust_address(rec, addr));
		new = ftrace_nop_replace(rec);
		ret = ftrace_modify_code(ip, old, new, true);
		}
		#endif

		return ret;
		}

		@@ -290,13 +246,6 @@ static int ftrace_modify_graph_caller(bool enable)
		#endif


		#ifdef CONFIG_OLD_MCOUNT
		if (!ret)
		ret = __ftrace_modify_caller(&ftrace_graph_call_old,
		ftrace_graph_caller_old,
		enable);
		#endif

		return ret;
		}

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