Commit 2ab3a0a9 authored by Heiko Carstens's avatar Heiko Carstens Committed by Vasily Gorbik
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s390/ftrace: add HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALL support 



This is the s390 variant of commit 562955fe ("ftrace/x86: Add
register_ftrace_direct() for custom trampolines").

Acked-by: default avatarIlya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: default avatarSven Schnelle <svens@linux.ibm.com>
Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
Acked-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20211012133802.2460757-2-hca@linux.ibm.com


Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
parent b2f58393

arch/s390/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -154,6 +154,7 @@ config S390 
	select HAVE_DMA_CONTIGUOUS

	select HAVE_DYNAMIC_FTRACE

	select HAVE_DYNAMIC_FTRACE_WITH_ARGS

	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS

	select HAVE_DYNAMIC_FTRACE_WITH_REGS

	select HAVE_EBPF_JIT if PACK_STACK && HAVE_MARCH_Z196_FEATURES

	select HAVE_EFFICIENT_UNALIGNED_ACCESS

arch/s390/include/asm/ftrace.h

+12 −0
Original line number Diff line number Diff line
@@ -58,6 +58,18 @@ static __always_inline void ftrace_instruction_pointer_set(struct ftrace_regs *f 
	regs->psw.addr = ip;

}



/*

 * When an ftrace registered caller is tracing a function that is

 * also set by a register_ftrace_direct() call, it needs to be

 * differentiated in the ftrace_caller trampoline. To do this,

 * place the direct caller in the ORIG_GPR2 part of pt_regs. This

 * tells the ftrace_caller that there's a direct caller.

 */

static inline void arch_ftrace_set_direct_caller(struct pt_regs *regs, unsigned long addr)

{

	regs->orig_gpr2 = addr;

}



/*

 * Even though the system call numbers are identical for s390/s390x a

 * different system call table is used for compat tasks. This may lead

arch/s390/kernel/mcount.S

+17 −6
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ ENDPROC(ftrace_stub) 
#define STACK_PTREGS		(STACK_FRAME_OVERHEAD)

#define STACK_PTREGS_GPRS	(STACK_PTREGS + __PT_GPRS)

#define STACK_PTREGS_PSW	(STACK_PTREGS + __PT_PSW)

#define STACK_PTREGS_ORIG_GPR2	(STACK_PTREGS + __PT_ORIG_GPR2)

#ifdef __PACK_STACK

/* allocate just enough for r14, r15 and backchain */

#define TRACED_FUNC_FRAME_SIZE	24
@@ -51,6 +52,7 @@ ENDPROC(ftrace_stub) 
	# allocate pt_regs and stack frame for ftrace_trace_function

	aghi	%r15,-STACK_FRAME_SIZE

	stg	%r1,(STACK_PTREGS_GPRS+15*8)(%r15)

	xc	STACK_PTREGS_ORIG_GPR2(8,%r15),STACK_PTREGS_ORIG_GPR2(%r15)



	.if \allregs == 1

	stg	%r14,(STACK_PTREGS_PSW)(%r15)
@@ -101,8 +103,17 @@ SYM_INNER_LABEL(ftrace_graph_caller, SYM_L_GLOBAL) 
	stg	%r2,(STACK_PTREGS_GPRS+14*8)(%r15)

.Lftrace_graph_caller_end:

#endif

	lg	%r1,(STACK_PTREGS_PSW+8)(%r15)

	lmg	%r2,%r15,(STACK_PTREGS_GPRS+2*8)(%r15)

	lg	%r0,(STACK_PTREGS_PSW+8)(%r15)

#ifdef CONFIG_HAVE_MARCH_Z196_FEATURES

	ltg	%r1,STACK_PTREGS_ORIG_GPR2(%r15)

	locgrz	%r1,%r0

#else

	lg	%r1,STACK_PTREGS_ORIG_GPR2(%r15)

	ltgr	%r1,%r1

	jnz	0f

	lgr	%r1,%r0

#endif

0:	lmg	%r2,%r15,(STACK_PTREGS_GPRS+2*8)(%r15)

	BR_EX	%r1

SYM_CODE_END(ftrace_common)