Commit 370011a2 authored by Naveen N. Rao's avatar Naveen N. Rao Committed by Michael Ellerman
Browse files

powerpc/ftrace: Enable HAVE_FUNCTION_GRAPH_RET_ADDR_PTR 



This associates entries in the ftrace_ret_stack with corresponding stack
frames, enabling more robust stack unwinding. Also update the only user
of ftrace_graph_ret_addr() to pass the stack pointer.

Signed-off-by: default avatarNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/0224f2d0971b069c678e2ff678cfc2cd1e114cfe.1567707399.git.naveen.n.rao@linux.vnet.ibm.com
parent a3db31ff

arch/powerpc/include/asm/asm-prototypes.h

+2 −1
Original line number Diff line number Diff line
@@ -134,7 +134,8 @@ extern int __ucmpdi2(u64, u64); 


/* tracing */

void _mcount(void);

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

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

						unsigned long sp);



void pnv_power9_force_smt4_catch(void);

void pnv_power9_force_smt4_release(void);

arch/powerpc/include/asm/ftrace.h

+2 −0
Original line number Diff line number Diff line
@@ -8,6 +8,8 @@ 
#define MCOUNT_ADDR		((unsigned long)(_mcount))

#define MCOUNT_INSN_SIZE	4 /* sizeof mcount call */



#define HAVE_FUNCTION_GRAPH_RET_ADDR_PTR



#ifdef __ASSEMBLY__



/* Based off of objdump optput from glibc */

arch/powerpc/kernel/stacktrace.c

+1 −1
Original line number Diff line number Diff line
@@ -182,7 +182,7 @@ static int __save_stack_trace_tsk_reliable(struct task_struct *tsk, 
		 * FIXME: IMHO these tests do not belong in

		 * arch-dependent code, they are generic.

		 */

		ip = ftrace_graph_ret_addr(tsk, &graph_idx, ip, NULL);

		ip = ftrace_graph_ret_addr(tsk, &graph_idx, ip, stack);

#ifdef CONFIG_KPROBES

		/*

		 * Mark stacktraces with kretprobed functions on them

arch/powerpc/kernel/trace/ftrace.c

+3 −2
Original line number Diff line number Diff line
@@ -944,7 +944,8 @@ int ftrace_disable_ftrace_graph_caller(void) 
 * Hook the return address and push it in the stack of return addrs

 * in current thread info. Return the address we want to divert to.

 */

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

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

						unsigned long sp)

{

	unsigned long return_hooker;
@@ -956,7 +957,7 @@ unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip) 


	return_hooker = ppc_function_entry(return_to_handler);



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

	if (!function_graph_enter(parent, ip, 0, (unsigned long *)sp))

		parent = return_hooker;

out:

	return parent;

arch/powerpc/kernel/trace/ftrace_32.S

+1 −0
Original line number Diff line number Diff line
@@ -50,6 +50,7 @@ _GLOBAL(ftrace_stub) 


#ifdef CONFIG_FUNCTION_GRAPH_TRACER

_GLOBAL(ftrace_graph_caller)

	addi	r5, r1, 48

	/* load r4 with local address */

	lwz	r4, 44(r1)

	subi	r4, r4, MCOUNT_INSN_SIZE

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