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Commit d983c89c authored by Vasily Gorbik's avatar Vasily Gorbik Committed by Steven Rostedt (VMware)
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s390/ftrace: Add -mfentry and -mnop-mcount support 

Utilize -mfentry and -mnop-mcount gcc options together with
-mrecord-mcount to get compiler generated calls to the profiling functions
as nops which are compatible with current -mhotpatch=0,3 approach.  At the
same time -mrecord-mcount enables __mcount_loc section generation by
the compiler which allows to avoid using scripts/recordmcount.pl script.

Link: http://lkml.kernel.org/r/patch-4.thread-aa7b8d.git-aa7b8dbf236f.your-ad-here.call-01533557518-ext-9465@work.hours



Reviewed-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent 2f4df001

arch/s390/Kconfig

+2 −0
Original line number Diff line number Diff line
@@ -136,6 +136,7 @@ config S390 
	select HAVE_DYNAMIC_FTRACE

	select HAVE_DYNAMIC_FTRACE_WITH_REGS

	select HAVE_EFFICIENT_UNALIGNED_ACCESS

	select HAVE_FENTRY

	select HAVE_FTRACE_MCOUNT_RECORD

	select HAVE_FUNCTION_GRAPH_TRACER

	select HAVE_FUNCTION_TRACER
@@ -157,6 +158,7 @@ config S390 
	select HAVE_MEMBLOCK_NODE_MAP

	select HAVE_MEMBLOCK_PHYS_MAP

	select HAVE_MOD_ARCH_SPECIFIC

	select HAVE_NOP_MCOUNT

	select HAVE_OPROFILE

	select HAVE_PERF_EVENTS

	select HAVE_REGS_AND_STACK_ACCESS_API

arch/s390/Makefile

+9 −7
Original line number Diff line number Diff line
@@ -86,6 +86,7 @@ ifdef CONFIG_EXPOLINE 
endif



ifdef CONFIG_FUNCTION_TRACER

  ifeq ($(call cc-option-yn,-mfentry -mnop-mcount),n)

    # make use of hotpatch feature if the compiler supports it

    cc_hotpatch	:= -mhotpatch=0,3

    ifeq ($(call cc-option-yn,$(cc_hotpatch)),y)
@@ -94,6 +95,7 @@ KBUILD_AFLAGS += -DCC_USING_HOTPATCH 
      KBUILD_CFLAGS	+= -DCC_USING_HOTPATCH

    endif

  endif

endif



# Test CFI features of binutils

cfi := $(call as-instr,.cfi_startproc\n.cfi_val_offset 15$(comma)-160\n.cfi_endproc,-DCONFIG_AS_CFI_VAL_OFFSET=1)

arch/s390/include/asm/ftrace.h

+3 −3
Original line number Diff line number Diff line
@@ -4,7 +4,7 @@ 


#define ARCH_SUPPORTS_FTRACE_OPS 1



#ifdef CC_USING_HOTPATCH

#if defined(CC_USING_HOTPATCH) || defined(CC_USING_NOP_MCOUNT)

#define MCOUNT_INSN_SIZE	6

#else

#define MCOUNT_INSN_SIZE	24
@@ -42,7 +42,7 @@ struct ftrace_insn { 
static inline void ftrace_generate_nop_insn(struct ftrace_insn *insn)

{

#ifdef CONFIG_FUNCTION_TRACER

#ifdef CC_USING_HOTPATCH

#if defined(CC_USING_HOTPATCH) || defined(CC_USING_NOP_MCOUNT)

	/* brcl 0,0 */

	insn->opc = 0xc004;

	insn->disp = 0;
@@ -57,7 +57,7 @@ static inline void ftrace_generate_nop_insn(struct ftrace_insn *insn) 
static inline int is_ftrace_nop(struct ftrace_insn *insn)

{

#ifdef CONFIG_FUNCTION_TRACER

#ifdef CC_USING_HOTPATCH

#if defined(CC_USING_HOTPATCH) || defined(CC_USING_NOP_MCOUNT)

	if (insn->disp == 0)

		return 1;

#else

arch/s390/kernel/ftrace.c

+1 −1
Original line number Diff line number Diff line
@@ -61,7 +61,7 @@ unsigned long ftrace_plt; 


static inline void ftrace_generate_orig_insn(struct ftrace_insn *insn)

{

#ifdef CC_USING_HOTPATCH

#if defined(CC_USING_HOTPATCH) || defined(CC_USING_NOP_MCOUNT)

	/* brcl 0,0 */

	insn->opc = 0xc004;

	insn->disp = 0;

arch/s390/kernel/mcount.S

+1 −1
Original line number Diff line number Diff line
@@ -35,7 +35,7 @@ ENTRY(ftrace_caller) 
	.globl	ftrace_regs_caller

	.set	ftrace_regs_caller,ftrace_caller

	lgr	%r1,%r15

#ifndef CC_USING_HOTPATCH

#if !(defined(CC_USING_HOTPATCH) || defined(CC_USING_NOP_MCOUNT))

	aghi	%r0,MCOUNT_RETURN_FIXUP

#endif

	aghi	%r15,-STACK_FRAME_SIZE