Commit 1256e70a authored by Sven Schnelle's avatar Sven Schnelle Committed by Heiko Carstens
Browse files

s390/ftrace: enable HAVE_FUNCTION_GRAPH_RETVAL 



Add support for tracing return values in the function graph tracer.
This requires return_to_handler() to record gpr2 and the frame pointer

Signed-off-by: default avatarSven Schnelle <svens@linux.ibm.com>
Reviewed-by: default avatarHeiko Carstens <hca@linux.ibm.com>
Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
parent 3325b4d8

arch/s390/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -174,6 +174,7 @@ config S390 
	select HAVE_FTRACE_MCOUNT_RECORD

	select HAVE_FUNCTION_ARG_ACCESS_API

	select HAVE_FUNCTION_ERROR_INJECTION

	select HAVE_FUNCTION_GRAPH_RETVAL

	select HAVE_FUNCTION_GRAPH_TRACER

	select HAVE_FUNCTION_TRACER

	select HAVE_GCC_PLUGINS

arch/s390/include/asm/ftrace.h

+17 −0
Original line number Diff line number Diff line
@@ -54,6 +54,23 @@ static __always_inline struct pt_regs *arch_ftrace_get_regs(struct ftrace_regs * 
	return NULL;

}



#ifdef CONFIG_FUNCTION_GRAPH_TRACER

struct fgraph_ret_regs {

	unsigned long gpr2;

	unsigned long fp;

};



static __always_inline unsigned long fgraph_ret_regs_return_value(struct fgraph_ret_regs *ret_regs)

{

	return ret_regs->gpr2;

}



static __always_inline unsigned long fgraph_ret_regs_frame_pointer(struct fgraph_ret_regs *ret_regs)

{

	return ret_regs->fp;

}

#endif /* CONFIG_FUNCTION_GRAPH_TRACER */



static __always_inline unsigned long

ftrace_regs_get_instruction_pointer(const struct ftrace_regs *fregs)

{

arch/s390/kernel/asm-offsets.c

+7 −0
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#include <linux/sched.h>

#include <linux/purgatory.h>

#include <linux/pgtable.h>

#include <linux/ftrace.h>

#include <asm/idle.h>

#include <asm/gmap.h>

#include <asm/stacktrace.h>
@@ -177,5 +178,11 @@ int main(void) 
	DEFINE(OLDMEM_SIZE, PARMAREA + offsetof(struct parmarea, oldmem_size));

	DEFINE(COMMAND_LINE, PARMAREA + offsetof(struct parmarea, command_line));

	DEFINE(MAX_COMMAND_LINE_SIZE, PARMAREA + offsetof(struct parmarea, max_command_line_size));

#ifdef CONFIG_FUNCTION_GRAPH_TRACER

	/* function graph return value tracing */

	OFFSET(__FGRAPH_RET_GPR2, fgraph_ret_regs, gpr2);

	OFFSET(__FGRAPH_RET_FP, fgraph_ret_regs, fp);

	DEFINE(__FGRAPH_RET_SIZE, sizeof(struct fgraph_ret_regs));

#endif

	return 0;

}

arch/s390/kernel/mcount.S

+6 −2
Original line number Diff line number Diff line
@@ -128,10 +128,14 @@ SYM_CODE_END(ftrace_common) 
SYM_FUNC_START(return_to_handler)

	stmg	%r2,%r5,32(%r15)

	lgr	%r1,%r15

	aghi	%r15,-STACK_FRAME_OVERHEAD

	aghi	%r15,-(STACK_FRAME_OVERHEAD+__FGRAPH_RET_SIZE)

	stg	%r1,__SF_BACKCHAIN(%r15)

	aghik	%r3,%r15,STACK_FRAME_OVERHEAD

	stg	%r1,__FGRAPH_RET_FP(%r3)

	stg	%r2,__FGRAPH_RET_GPR2(%r3)

	lgr	%r2,%r3

	brasl	%r14,ftrace_return_to_handler

	aghi	%r15,STACK_FRAME_OVERHEAD

	aghi	%r15,STACK_FRAME_OVERHEAD+__FGRAPH_RET_SIZE

	lgr	%r14,%r2

	lmg	%r2,%r5,32(%r15)

	BR_EX	%r14