Commit 53255c9a authored by Heiko Carstens's avatar Heiko Carstens Committed by Martin Schwidefsky
Browse files

s390/ftrace: remove 31 bit ftrace support 



31 bit and 64 bit diverge more and more and it is rather painful
to keep both parts running.
To make things simpler just remove the 31 bit support which nobody
uses anyway.

Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent a62bc073

arch/s390/Kconfig

+3 −3
Original line number Diff line number Diff line
@@ -117,11 +117,11 @@ config S390 
	select HAVE_CMPXCHG_LOCAL

	select HAVE_C_RECORDMCOUNT

	select HAVE_DEBUG_KMEMLEAK

	select HAVE_DYNAMIC_FTRACE

	select HAVE_DYNAMIC_FTRACE if 64BIT

	select HAVE_DYNAMIC_FTRACE_WITH_REGS if 64BIT

	select HAVE_FTRACE_MCOUNT_RECORD

	select HAVE_FUNCTION_GRAPH_TRACER

	select HAVE_FUNCTION_TRACER

	select HAVE_FUNCTION_GRAPH_TRACER if 64BIT

	select HAVE_FUNCTION_TRACER if 64BIT

	select HAVE_FUTEX_CMPXCHG if FUTEX

	select HAVE_KERNEL_BZIP2

	select HAVE_KERNEL_GZIP

arch/s390/include/asm/ftrace.h

+0 −6
Original line number Diff line number Diff line
@@ -18,14 +18,8 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr) 


#endif /* __ASSEMBLY__ */



#ifdef CONFIG_64BIT

#define MCOUNT_INSN_SIZE  18

#else

#define MCOUNT_INSN_SIZE  22

#endif



#ifdef CONFIG_64BIT

#define ARCH_SUPPORTS_FTRACE_OPS 1

#endif



#endif /* _ASM_S390_FTRACE_H */

arch/s390/kernel/Makefile

+1 −2
Original line number Diff line number Diff line
@@ -52,8 +52,7 @@ obj-$(CONFIG_COMPAT) += compat_wrapper.o $(compat-obj-y) 


obj-$(CONFIG_STACKTRACE)	+= stacktrace.o

obj-$(CONFIG_KPROBES)		+= kprobes.o

obj-$(CONFIG_FUNCTION_TRACER)	+= $(if $(CONFIG_64BIT),mcount64.o,mcount.o)

obj-$(CONFIG_FUNCTION_TRACER)	+= ftrace.o

obj-$(CONFIG_FUNCTION_TRACER)	+= mcount.o ftrace.o

obj-$(CONFIG_CRASH_DUMP)	+= crash_dump.o

obj-$(CONFIG_UPROBES)		+= uprobes.o

arch/s390/kernel/ftrace.c

+2 −77
Original line number Diff line number Diff line
@@ -21,9 +21,8 @@ void mcount_replace_code(void); 
void ftrace_disable_code(void);

void ftrace_enable_insn(void);



#ifdef CONFIG_64BIT

/*

 * The 64-bit mcount code looks like this:

 * The mcount code looks like this:

 *	stg	%r14,8(%r15)		# offset 0

 *	larl	%r1,<&counter>		# offset 6

 *	brasl	%r14,_mcount		# offset 12
@@ -34,7 +33,7 @@ void ftrace_enable_insn(void); 
 * Note: we do not patch the first instruction to an unconditional branch,

 * since that would break kprobes/jprobes. It is easier to leave the larl

 * instruction in and only modify the second instruction.

 * The 64-bit enabled ftrace code block looks like this:

 * The enabled ftrace code block looks like this:

 *	larl	%r0,.+24		# offset 0

 * >	lg	%r1,__LC_FTRACE_FUNC	# offset 6

 *	br	%r1			# offset 12
@@ -71,65 +70,15 @@ asm( 
#define MCOUNT_INSN_OFFSET	6

#define FTRACE_INSN_SIZE	6



#else /* CONFIG_64BIT */

/*

 * The 31-bit mcount code looks like this:

 *	st	%r14,4(%r15)		# offset 0

 * >	bras	%r1,0f			# offset 4

 * >	.long	_mcount			# offset 8

 * >	.long	<&counter>		# offset 12

 * > 0:	l	%r14,0(%r1)		# offset 16

 * >	l	%r1,4(%r1)		# offset 20

 *	basr	%r14,%r14		# offset 24

 *	l	%r14,4(%r15)		# offset 26

 * Total length is 30 bytes. The twenty bytes starting from offset 4

 * to offset 24 get overwritten by ftrace_make_nop / ftrace_make_call.

 * The 31-bit enabled ftrace code block looks like this:

 *	st	%r14,4(%r15)		# offset 0

 * >	l	%r14,__LC_FTRACE_FUNC	# offset 4

 * >	j	0f			# offset 8

 * >	.fill	12,1,0x07		# offset 12

 *   0:	basr	%r14,%r14		# offset 24

 *	l	%r14,4(%r14)		# offset 26

 * The return points of the mcount/ftrace function have the same offset 26.

 * The 31-bit disabled ftrace code block looks like this:

 *	st	%r14,4(%r15)		# offset 0

 * >	j	.+26			# offset 4

 * >	j	0f			# offset 8

 * >	.fill	12,1,0x07		# offset 12

 *   0:	basr	%r14,%r14		# offset 24

 *	l	%r14,4(%r14)		# offset 26

 * The j instruction branches to offset 30 to skip as many instructions

 * as possible.

 */

asm(

	"	.align	4\n"

	"ftrace_disable_code:\n"

	"	j	1f\n"

	"	j	0f\n"

	"	.fill	12,1,0x07\n"

	"0:	basr	%r14,%r14\n"

	"1:\n"

	"	.align	4\n"

	"ftrace_enable_insn:\n"

	"	l	%r14,"__stringify(__LC_FTRACE_FUNC)"\n");



#define FTRACE_INSN_SIZE	4



#endif /* CONFIG_64BIT */



#ifdef CONFIG_64BIT

int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,

		       unsigned long addr)

{

	return 0;

}

#endif



int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,

		    unsigned long addr)

{

#ifdef CONFIG_64BIT

	/* Initial replacement of the whole mcount block */

	if (addr == MCOUNT_ADDR) {

		if (probe_kernel_write((void *) rec->ip - MCOUNT_INSN_OFFSET,
@@ -138,7 +87,6 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, 
			return -EPERM;

		return 0;

	}

#endif

	if (probe_kernel_write((void *) rec->ip, ftrace_disable_code,

			       MCOUNT_INSN_SIZE))

		return -EPERM;
@@ -196,8 +144,6 @@ out: 
 * the original offset to prepare_ftrace_return and put it back.

 */



#ifdef CONFIG_64BIT



int ftrace_enable_ftrace_graph_caller(void)

{

	static unsigned short offset = 0x0002;
@@ -216,25 +162,4 @@ int ftrace_disable_ftrace_graph_caller(void) 
				  &offset, sizeof(offset));

}



#else /* CONFIG_64BIT */



int ftrace_enable_ftrace_graph_caller(void)

{

	unsigned short offset;



	offset = ((void *) prepare_ftrace_return -

		  (void *) ftrace_graph_caller) / 2;

	return probe_kernel_write((void *) ftrace_graph_caller + 2,

				  &offset, sizeof(offset));

}



int ftrace_disable_ftrace_graph_caller(void)

{

	static unsigned short offset = 0x0002;



	return probe_kernel_write((void *) ftrace_graph_caller + 2,

				  &offset, sizeof(offset));

}



#endif /* CONFIG_64BIT */

#endif /* CONFIG_FUNCTION_GRAPH_TRACER */

arch/s390/kernel/mcount.S

+50 −37
Original line number Diff line number Diff line
@@ -8,60 +8,73 @@ 
#include <linux/linkage.h>

#include <asm/asm-offsets.h>

#include <asm/ftrace.h>

#include <asm/ptrace.h>



	.section .kprobes.text, "ax"



ENTRY(ftrace_stub)

	br	%r14



#define STACK_FRAME_SIZE  (STACK_FRAME_OVERHEAD + __PT_SIZE)

#define STACK_PTREGS	  (STACK_FRAME_OVERHEAD)

#define STACK_PTREGS_GPRS (STACK_PTREGS + __PT_GPRS)

#define STACK_PTREGS_PSW  (STACK_PTREGS + __PT_PSW)



ENTRY(_mcount)

	br	%r14



ENTRY(ftrace_caller)

	stm	%r2,%r5,16(%r15)

	bras	%r1,1f

0:	.long	ftrace_trace_function

1:	st	%r14,56(%r15)

	lr	%r0,%r15

	ahi	%r15,-96

	l	%r3,100(%r15)

	la	%r2,0(%r14)

	st	%r0,__SF_BACKCHAIN(%r15)

	la	%r3,0(%r3)

	ahi	%r2,-MCOUNT_INSN_SIZE

	l	%r14,0b-0b(%r1)

	l	%r14,0(%r14)

	basr	%r14,%r14

	.globl	ftrace_regs_caller

	.set	ftrace_regs_caller,ftrace_caller

	lgr	%r1,%r15

	aghi	%r15,-STACK_FRAME_SIZE

	stg	%r1,__SF_BACKCHAIN(%r15)

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

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

	stmg	%r2,%r14,(STACK_PTREGS_GPRS+2*8)(%r15)

#ifdef CONFIG_HAVE_MARCH_Z196_FEATURES

	aghik	%r2,%r0,-MCOUNT_INSN_SIZE

	lgrl	%r4,function_trace_op

	lgrl	%r1,ftrace_trace_function

#else

	lgr	%r2,%r0

	aghi	%r2,-MCOUNT_INSN_SIZE

	larl	%r4,function_trace_op

	lg	%r4,0(%r4)

	larl	%r1,ftrace_trace_function

	lg	%r1,0(%r1)

#endif

	lgr	%r3,%r14

	la	%r5,STACK_PTREGS(%r15)

	basr	%r14,%r1

#ifdef CONFIG_FUNCTION_GRAPH_TRACER

	l	%r2,100(%r15)

	l	%r3,152(%r15)

ENTRY(ftrace_graph_caller)

# The bras instruction gets runtime patched to call prepare_ftrace_return.

# The j instruction gets runtime patched to a nop instruction.

# See ftrace_enable_ftrace_graph_caller. The patched instruction is:

#	bras	%r14,prepare_ftrace_return

	bras	%r14,0f

0:	st	%r2,100(%r15)

#	j	.+4

ENTRY(ftrace_graph_caller)

	j	ftrace_graph_caller_end

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

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

	brasl	%r14,prepare_ftrace_return

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

ftrace_graph_caller_end:

	.globl	ftrace_graph_caller_end

#endif

	ahi	%r15,96

	l	%r14,56(%r15)

	lm	%r2,%r5,16(%r15)

	br	%r14

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

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

	br	%r1



#ifdef CONFIG_FUNCTION_GRAPH_TRACER



ENTRY(return_to_handler)

	stm	%r2,%r5,16(%r15)

	st	%r14,56(%r15)

	lr	%r0,%r15

	ahi	%r15,-96

	st	%r0,__SF_BACKCHAIN(%r15)

	bras	%r1,0f

	.long	ftrace_return_to_handler

0:	l	%r2,0b-0b(%r1)

	basr	%r14,%r2

	lr	%r14,%r2

	ahi	%r15,96

	lm	%r2,%r5,16(%r15)

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

	lgr	%r1,%r15

	aghi	%r15,-STACK_FRAME_OVERHEAD

	stg	%r1,__SF_BACKCHAIN(%r15)

	brasl	%r14,ftrace_return_to_handler

	aghi	%r15,STACK_FRAME_OVERHEAD

	lgr	%r14,%r2

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

	br	%r14



#endif

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