linux/arch/s390/kernel/mcount.S
Heiko Carstens 0cccdda8d1 s390/ftrace: simplify enabling/disabling of ftrace_graph_caller
We can simply patch the mask field within the branch relative on
condition instruction at the beginning of the ftrace_graph_caller
code block.
This makes the logic even simpler and we get rid of the displacement
calculation.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2014-10-09 09:14:20 +02:00

80 lines
1.9 KiB
ArmAsm

/*
* Copyright IBM Corp. 2008, 2009
*
* Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>,
*
*/
#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)
.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
# The j instruction gets runtime patched to a nop instruction.
# See ftrace_enable_ftrace_graph_caller.
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
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)
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