This code is based on a patch from Vojtech Pavlik. http://marc.info/?l=linux-s390&m=140438885114413&w=2 The actual implementation now differs significantly: Instead of adding a second function "ftrace_regs_caller" which would be nearly identical to the existing ftrace_caller function, the current ftrace_caller function is now an alias to ftrace_regs_caller and always passes the needed pt_regs structure and function_trace_op parameters unconditionally. Besides that also use asm offsets to correctly allocate and access the new struct pt_regs on the stack. While at it we can make use of new instruction to get rid of some indirect loads if compiled for new machines. The passed struct pt_regs can be changed by the called function and it's new contents will replace the current contents. E.g. r14 can be modified to change the return address of a traced function. We explicitly do not use the psw_t member of struct pt_regs to pass (and modify) r14, since that would result in a fake psw where the mask member is invalid. In addition r14 and the psw_t member have different semantics anyway. Cc: Vojtech Pavlik <vojtech@xxxxxxx> Cc: Jiri Kosina <jkosina@xxxxxxx> Cc: Jiri Slaby <jslaby@xxxxxxx> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx> Signed-off-by: Heiko Carstens <heiko.carstens@xxxxxxxxxx> --- arch/s390/Kconfig | 1 + arch/s390/include/asm/ftrace.h | 4 ++++ arch/s390/kernel/ftrace.c | 5 +++++ arch/s390/kernel/mcount64.S | 45 ++++++++++++++++++++++++++++-------------- 4 files changed, 40 insertions(+), 15 deletions(-) diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index ab39ceb89ecf..2d935cb77393 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -116,6 +116,7 @@ config S390 select HAVE_C_RECORDMCOUNT select HAVE_DEBUG_KMEMLEAK select HAVE_DYNAMIC_FTRACE + select HAVE_DYNAMIC_FTRACE_WITH_REGS if 64BIT select HAVE_FTRACE_MCOUNT_RECORD select HAVE_FUNCTION_GRAPH_TRACER select HAVE_FUNCTION_TRACER diff --git a/arch/s390/include/asm/ftrace.h b/arch/s390/include/asm/ftrace.h index 874f903c2eb4..d419362dc231 100644 --- a/arch/s390/include/asm/ftrace.h +++ b/arch/s390/include/asm/ftrace.h @@ -24,4 +24,8 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr) #define MCOUNT_INSN_SIZE 22 #endif +#ifdef CONFIG_64BIT +#define ARCH_SUPPORTS_FTRACE_OPS 1 +#endif + #endif /* _ASM_S390_FTRACE_H */ diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c index 7dc7df3857c4..69eb49ccf8a4 100644 --- a/arch/s390/kernel/ftrace.c +++ b/arch/s390/kernel/ftrace.c @@ -107,6 +107,11 @@ asm( #endif /* CONFIG_64BIT */ +int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, + unsigned long addr) +{ + return 0; +} int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr) diff --git a/arch/s390/kernel/mcount64.S b/arch/s390/kernel/mcount64.S index b03896d29274..92f8994f37b8 100644 --- a/arch/s390/kernel/mcount64.S +++ b/arch/s390/kernel/mcount64.S @@ -8,45 +8,60 @@ #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_PARENT_IP (STACK_FRAME_SIZE + 8) +#define STACK_PTREGS (STACK_FRAME_OVERHEAD) +#define STACK_PTREGS_GPRS (STACK_PTREGS + __PT_GPRS) + ENTRY(_mcount) #ifdef CONFIG_DYNAMIC_FTRACE br %r14 ENTRY(ftrace_caller) + .globl ftrace_regs_caller + .set ftrace_regs_caller,ftrace_caller #endif - stmg %r2,%r5,32(%r15) - stg %r14,112(%r15) lgr %r1,%r15 - aghi %r15,-160 + aghi %r15,-STACK_FRAME_SIZE stg %r1,__SF_BACKCHAIN(%r15) + stg %r1,(STACK_PTREGS_GPRS+15*8)(%r15) + stmg %r0,%r14,STACK_PTREGS_GPRS(%r15) +#ifdef CONFIG_HAVE_MARCH_Z196_FEATURES + aghik %r2,%r14,-MCOUNT_INSN_SIZE + lgrl %r4,function_trace_op + lgrl %r14,ftrace_trace_function +#else lgr %r2,%r14 - lg %r3,168(%r15) aghi %r2,-MCOUNT_INSN_SIZE + larl %r4,function_trace_op + lg %r4,0(%r4) larl %r14,ftrace_trace_function lg %r14,0(%r14) +#endif + lg %r3,STACK_PARENT_IP(%r15) + la %r5,STACK_PTREGS(%r15) basr %r14,%r14 #ifdef CONFIG_FUNCTION_GRAPH_TRACER -# The j instruction gets runtime patched to a nop instruction. +ENTRY(ftrace_graph_caller) +# The bras instruction gets runtime patched to call prepare_ftrace_return. # See ftrace_enable_ftrace_graph_caller. The patched instruction is: # j .+2 -ENTRY(ftrace_graph_caller) j ftrace_graph_caller_end - lg %r2,168(%r15) - lg %r3,272(%r15) - brasl %r14,prepare_ftrace_return - stg %r2,168(%r15) + lg %r2,STACK_PARENT_IP(%r15) + lg %r3,(STACK_PTREGS_GPRS+14*8)(%r15) + bras %r14,prepare_ftrace_return + stg %r2,STACK_PARENT_IP(%r15) ftrace_graph_caller_end: .globl ftrace_graph_caller_end #endif - aghi %r15,160 - lmg %r2,%r5,32(%r15) - lg %r14,112(%r15) + lmg %r0,%r15,STACK_PTREGS_GPRS(%r15) br %r14 #ifdef CONFIG_FUNCTION_GRAPH_TRACER @@ -54,10 +69,10 @@ ftrace_graph_caller_end: ENTRY(return_to_handler) stmg %r2,%r5,32(%r15) lgr %r1,%r15 - aghi %r15,-160 + aghi %r15,-STACK_FRAME_OVERHEAD stg %r1,__SF_BACKCHAIN(%r15) brasl %r14,ftrace_return_to_handler - aghi %r15,160 + aghi %r15,STACK_FRAME_OVERHEAD lgr %r14,%r2 lmg %r2,%r5,32(%r15) br %r14 -- 1.8.5.5 -- To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
