Commit ec7bf478 authored by Martin Schwidefsky's avatar Martin Schwidefsky
Browse files

s390/ftrace: use HAVE_FUNCTION_GRAPH_RET_ADDR_PTR 



Make the call chain more reliable by tagging the ftrace stack entries
with the stack pointer that is associated with the return address.

Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 78c98f90

arch/s390/include/asm/ftrace.h

+2 −0
Original line number Diff line number Diff line
@@ -11,6 +11,8 @@ 
#define MCOUNT_RETURN_FIXUP	18

#endif



#define HAVE_FUNCTION_GRAPH_RET_ADDR_PTR



#ifndef __ASSEMBLY__



#ifdef CONFIG_CC_IS_CLANG

arch/s390/kernel/entry.h

+1 −1
Original line number Diff line number Diff line
@@ -65,7 +65,7 @@ int setup_profiling_timer(unsigned int multiplier); 
void __init time_init(void);

int pfn_is_nosave(unsigned long);

void s390_early_resume(void);

unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip);

unsigned long prepare_ftrace_return(unsigned long parent, unsigned long sp, unsigned long ip);



struct s390_mmap_arg_struct;

struct fadvise64_64_args;

arch/s390/kernel/ftrace.c

+5 −4
Original line number Diff line number Diff line
@@ -201,17 +201,18 @@ device_initcall(ftrace_plt_init); 
 * Hook the return address and push it in the stack of return addresses

 * in current thread info.

 */

unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip)

unsigned long prepare_ftrace_return(unsigned long ra, unsigned long sp,

				    unsigned long ip)

{

	if (unlikely(ftrace_graph_is_dead()))

		goto out;

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

		goto out;

	ip -= MCOUNT_INSN_SIZE;

	if (!function_graph_enter(parent, ip, 0, NULL))

		parent = (unsigned long) return_to_handler;

	if (!function_graph_enter(ra, ip, 0, (void *) sp))

		ra = (unsigned long) return_to_handler;

out:

	return parent;

	return ra;

}

NOKPROBE_SYMBOL(prepare_ftrace_return);

arch/s390/kernel/mcount.S

+2 −2
Original line number Diff line number Diff line
@@ -65,8 +65,8 @@ ENTRY(ftrace_caller) 
	.globl ftrace_graph_caller

ftrace_graph_caller:

	j	ftrace_graph_caller_end

	lg	%r2,(STACK_PTREGS_GPRS+14*8)(%r15)

	lg	%r3,(STACK_PTREGS_PSW+8)(%r15)

	lmg	%r2,%r3,(STACK_PTREGS_GPRS+14*8)(%r15)

	lg	%r4,(STACK_PTREGS_PSW+8)(%r15)

	brasl	%r14,prepare_ftrace_return

	stg	%r2,(STACK_PTREGS_GPRS+14*8)(%r15)

ftrace_graph_caller_end:

arch/s390/kernel/unwind_bc.c

+1 −1
Original line number Diff line number Diff line
@@ -84,7 +84,7 @@ bool unwind_next_frame(struct unwind_state *state) 
	/* Decode any ftrace redirection */

	if (ip == (unsigned long) return_to_handler)

		ip = ftrace_graph_ret_addr(state->task, &state->graph_idx,

					   ip, NULL);

					   ip, (void *) sp);

#endif



	/* Update unwind state */

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