diff options
| -rw-r--r-- | arch/s390/include/asm/ftrace.h | 1 | ||||
| -rw-r--r-- | arch/s390/kernel/ftrace.c | 24 | ||||
| -rw-r--r-- | arch/s390/kernel/mcount64.S | 15 |
3 files changed, 34 insertions, 6 deletions
diff --git a/arch/s390/include/asm/ftrace.h b/arch/s390/include/asm/ftrace.h index bf246dae1367..7b8e456d76c9 100644 --- a/arch/s390/include/asm/ftrace.h +++ b/arch/s390/include/asm/ftrace.h @@ -4,6 +4,7 @@ #ifndef __ASSEMBLY__ extern void _mcount(void); +extern char ftrace_graph_caller_end; struct dyn_arch_ftrace { }; diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c index 54d6493c4a56..de55efa5b64e 100644 --- a/arch/s390/kernel/ftrace.c +++ b/arch/s390/kernel/ftrace.c @@ -170,6 +170,29 @@ out: * directly after the instructions. To enable the call we calculate * 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; + + return probe_kernel_write((void *) ftrace_graph_caller + 2, + &offset, sizeof(offset)); +} + +int ftrace_disable_ftrace_graph_caller(void) +{ + unsigned short offset; + + offset = ((void *) &ftrace_graph_caller_end - + (void *) ftrace_graph_caller) / 2; + return probe_kernel_write((void *) ftrace_graph_caller + 2, + &offset, sizeof(offset)); +} + +#else /* CONFIG_64BIT */ + int ftrace_enable_ftrace_graph_caller(void) { unsigned short offset; @@ -188,5 +211,6 @@ int ftrace_disable_ftrace_graph_caller(void) &offset, sizeof(offset)); } +#endif /* CONFIG_64BIT */ #endif /* CONFIG_DYNAMIC_FTRACE */ #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ diff --git a/arch/s390/kernel/mcount64.S b/arch/s390/kernel/mcount64.S index c67a8bf0fd9a..5b33c83adde9 100644 --- a/arch/s390/kernel/mcount64.S +++ b/arch/s390/kernel/mcount64.S @@ -32,14 +32,17 @@ ENTRY(ftrace_caller) lg %r14,0(%r14) basr %r14,%r14 #ifdef CONFIG_FUNCTION_GRAPH_TRACER +# The j instruction gets runtime patched to a nop instruction. +# See ftrace_enable_ftrace_graph_caller. The patched instruction is: +# j .+4 +ENTRY(ftrace_graph_caller) + j ftrace_graph_caller_end lg %r2,168(%r15) lg %r3,272(%r15) -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: -# bras %r14,prepare_ftrace_return - bras %r14,0f -0: stg %r2,168(%r15) + brasl %r14,prepare_ftrace_return + stg %r2,168(%r15) +ftrace_graph_caller_end: + .globl ftrace_graph_caller_end #endif aghi %r15,160 lmg %r2,%r5,32(%r15) |