diff options
Diffstat (limited to 'arch/blackfin/kernel/ftrace-entry.S')
| -rw-r--r-- | arch/blackfin/kernel/ftrace-entry.S | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/arch/blackfin/kernel/ftrace-entry.S b/arch/blackfin/kernel/ftrace-entry.S index ce71487b515f..6980b7a0615d 100644 --- a/arch/blackfin/kernel/ftrace-entry.S +++ b/arch/blackfin/kernel/ftrace-entry.S @@ -35,6 +35,28 @@ ENTRY(__mcount) cc = r2 == r3; if ! cc jump .Ldo_trace; +#ifdef CONFIG_FUNCTION_GRAPH_TRACER + /* if the ftrace_graph_return function pointer is not set to + * the ftrace_stub entry, call prepare_ftrace_return(). + */ + p0.l = _ftrace_graph_return; + p0.h = _ftrace_graph_return; + r3 = [p0]; + cc = r2 == r3; + if ! cc jump _ftrace_graph_caller; + + /* similarly, if the ftrace_graph_entry function pointer is not + * set to the ftrace_graph_entry_stub entry, ... + */ + p0.l = _ftrace_graph_entry; + p0.h = _ftrace_graph_entry; + r2.l = _ftrace_graph_entry_stub; + r2.h = _ftrace_graph_entry_stub; + r3 = [p0]; + cc = r2 == r3; + if ! cc jump _ftrace_graph_caller; +#endif + r2 = [sp++]; rts; @@ -61,6 +83,7 @@ ENTRY(__mcount) call (p0); /* restore state and get out of dodge */ +.Lfinish_trace: rets = [sp++]; r1 = [sp++]; r0 = [sp++]; @@ -70,3 +93,48 @@ ENTRY(__mcount) _ftrace_stub: rts; ENDPROC(__mcount) + +#ifdef CONFIG_FUNCTION_GRAPH_TRACER +/* The prepare_ftrace_return() function is similar to the trace function + * except it takes a pointer to the location of the frompc. This is so + * the prepare_ftrace_return() can hijack it temporarily for probing + * purposes. + */ +ENTRY(_ftrace_graph_caller) + /* save first/second function arg and the return register */ + [--sp] = r0; + [--sp] = r1; + [--sp] = rets; + + r0 = fp; + r1 = rets; + r0 += 4; + r1 += -MCOUNT_INSN_SIZE; + call _prepare_ftrace_return; + + jump .Lfinish_trace; +ENDPROC(_ftrace_graph_caller) + +/* Undo the rewrite caused by ftrace_graph_caller(). The common function + * ftrace_return_to_handler() will return the original rets so we can + * restore it and be on our way. + */ +ENTRY(_return_to_handler) + /* make sure original return values are saved */ + [--sp] = p0; + [--sp] = r0; + [--sp] = r1; + + /* get original return address */ + call _ftrace_return_to_handler; + rets = r0; + + /* anomaly 05000371 - make sure we have at least three instructions + * between rets setting and the return + */ + r1 = [sp++]; + r0 = [sp++]; + p0 = [sp++]; + rts; +ENDPROC(_return_to_handler) +#endif |
