From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- arch/blackfin/kernel/ftrace-entry.S | 207 ++++++++++++++++++++++++++++++++++++ 1 file changed, 207 insertions(+) create mode 100644 arch/blackfin/kernel/ftrace-entry.S (limited to 'arch/blackfin/kernel/ftrace-entry.S') diff --git a/arch/blackfin/kernel/ftrace-entry.S b/arch/blackfin/kernel/ftrace-entry.S new file mode 100644 index 000000000..28d059540 --- /dev/null +++ b/arch/blackfin/kernel/ftrace-entry.S @@ -0,0 +1,207 @@ +/* + * mcount and friends -- ftrace stuff + * + * Copyright (C) 2009-2010 Analog Devices Inc. + * Licensed under the GPL-2 or later. + */ + +#include +#include + +.text + +#ifdef CONFIG_DYNAMIC_FTRACE + +/* Simple stub so we can boot the kernel until runtime patching has + * disabled all calls to this. Then it'll be unused. + */ +ENTRY(__mcount) +# if ANOMALY_05000371 + nop; nop; nop; nop; +# endif + rts; +ENDPROC(__mcount) + +/* GCC will have called us before setting up the function prologue, so we + * can clobber the normal scratch registers, but we need to make sure to + * save/restore the registers used for argument passing (R0-R2) in case + * the profiled function is using them. With data registers, R3 is the + * only one we can blow away. With pointer registers, we have P0-P2. + * + * Upon entry, the RETS will point to the top of the current profiled + * function. And since GCC pushed the previous RETS for us, the previous + * function will be waiting there. mmmm pie. + */ +ENTRY(_ftrace_caller) + /* save first/second/third function arg and the return register */ + [--sp] = r2; + [--sp] = r0; + [--sp] = r1; + [--sp] = rets; + + /* function_trace_call(unsigned long ip, unsigned long parent_ip): + * ip: this point was called by ... + * parent_ip: ... this function + * the ip itself will need adjusting for the mcount call + */ + r0 = rets; + r1 = [sp + 16]; /* skip the 4 local regs on stack */ + r0 += -MCOUNT_INSN_SIZE; + +.globl _ftrace_call +_ftrace_call: + call _ftrace_stub + +# ifdef CONFIG_FUNCTION_GRAPH_TRACER +.globl _ftrace_graph_call +_ftrace_graph_call: + nop; /* jump _ftrace_graph_caller; */ +# endif + + /* restore state and get out of dodge */ +.Lfinish_trace: + rets = [sp++]; + r1 = [sp++]; + r0 = [sp++]; + r2 = [sp++]; + +.globl _ftrace_stub +_ftrace_stub: + rts; +ENDPROC(_ftrace_caller) + +#else + +/* See documentation for _ftrace_caller */ +ENTRY(__mcount) + /* save third function arg early so we can do testing below */ + [--sp] = r2; + + /* load the function pointer to the tracer */ + p0.l = _ftrace_trace_function; + p0.h = _ftrace_trace_function; + r3 = [p0]; + + /* optional micro optimization: don't call the stub tracer */ + r2.l = _ftrace_stub; + r2.h = _ftrace_stub; + 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; + +.Ldo_trace: + + /* save first/second function arg and the return register */ + [--sp] = r0; + [--sp] = r1; + [--sp] = rets; + + /* setup the tracer function */ + p0 = r3; + + /* function_trace_call(unsigned long ip, unsigned long parent_ip): + * ip: this point was called by ... + * parent_ip: ... this function + * the ip itself will need adjusting for the mcount call + */ + r0 = rets; + r1 = [sp + 16]; /* skip the 4 local regs on stack */ + r0 += -MCOUNT_INSN_SIZE; + + /* call the tracer */ + call (p0); + + /* restore state and get out of dodge */ +.Lfinish_trace: + rets = [sp++]; + r1 = [sp++]; + r0 = [sp++]; + r2 = [sp++]; + +.globl _ftrace_stub +_ftrace_stub: + rts; +ENDPROC(__mcount) + +#endif + +#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) +# ifndef CONFIG_DYNAMIC_FTRACE + /* save first/second function arg and the return register */ + [--sp] = r0; + [--sp] = r1; + [--sp] = rets; + + /* prepare_ftrace_return(parent, self_addr, frame_pointer) */ + r0 = sp; /* unsigned long *parent */ + r1 = rets; /* unsigned long self_addr */ +# else + r0 = sp; /* unsigned long *parent */ + r1 = [sp]; /* unsigned long self_addr */ +# endif +# ifdef CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST + r2 = fp; /* unsigned long frame_pointer */ +# endif + r0 += 16; /* skip the 4 local regs on stack */ + 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 */ +# ifdef CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST + r0 = fp; /* Blackfin is sane, so omit this */ +# endif + 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 -- cgit v1.2.3-54-g00ecf