Mike Frysinger | 1c873be | 2009-06-09 07:25:09 -0400 | [diff] [blame] | 1 | /* |
| 2 | * mcount and friends -- ftrace stuff |
| 3 | * |
Mike Frysinger | aebfef0 | 2010-01-22 07:35:20 -0500 | [diff] [blame] | 4 | * Copyright (C) 2009-2010 Analog Devices Inc. |
Mike Frysinger | 1c873be | 2009-06-09 07:25:09 -0400 | [diff] [blame] | 5 | * Licensed under the GPL-2 or later. |
| 6 | */ |
| 7 | |
| 8 | #include <linux/linkage.h> |
| 9 | #include <asm/ftrace.h> |
| 10 | |
| 11 | .text |
| 12 | |
Mike Frysinger | f507442 | 2010-07-21 09:13:02 -0400 | [diff] [blame] | 13 | #ifdef CONFIG_DYNAMIC_FTRACE |
| 14 | |
| 15 | /* Simple stub so we can boot the kernel until runtime patching has |
| 16 | * disabled all calls to this. Then it'll be unused. |
| 17 | */ |
| 18 | ENTRY(__mcount) |
| 19 | # if ANOMALY_05000371 |
| 20 | nop; nop; nop; nop; |
| 21 | # endif |
| 22 | rts; |
| 23 | ENDPROC(__mcount) |
| 24 | |
Mike Frysinger | 1c873be | 2009-06-09 07:25:09 -0400 | [diff] [blame] | 25 | /* GCC will have called us before setting up the function prologue, so we |
| 26 | * can clobber the normal scratch registers, but we need to make sure to |
| 27 | * save/restore the registers used for argument passing (R0-R2) in case |
| 28 | * the profiled function is using them. With data registers, R3 is the |
| 29 | * only one we can blow away. With pointer registers, we have P0-P2. |
| 30 | * |
| 31 | * Upon entry, the RETS will point to the top of the current profiled |
Yi Li | 5bf9cbe | 2009-09-15 09:24:31 +0000 | [diff] [blame] | 32 | * function. And since GCC pushed the previous RETS for us, the previous |
| 33 | * function will be waiting there. mmmm pie. |
Mike Frysinger | 1c873be | 2009-06-09 07:25:09 -0400 | [diff] [blame] | 34 | */ |
Mike Frysinger | f507442 | 2010-07-21 09:13:02 -0400 | [diff] [blame] | 35 | ENTRY(_ftrace_caller) |
Mike Frysinger | f507442 | 2010-07-21 09:13:02 -0400 | [diff] [blame] | 36 | /* save first/second/third function arg and the return register */ |
| 37 | [--sp] = r2; |
| 38 | [--sp] = r0; |
| 39 | [--sp] = r1; |
| 40 | [--sp] = rets; |
| 41 | |
| 42 | /* function_trace_call(unsigned long ip, unsigned long parent_ip): |
| 43 | * ip: this point was called by ... |
| 44 | * parent_ip: ... this function |
| 45 | * the ip itself will need adjusting for the mcount call |
| 46 | */ |
| 47 | r0 = rets; |
| 48 | r1 = [sp + 16]; /* skip the 4 local regs on stack */ |
| 49 | r0 += -MCOUNT_INSN_SIZE; |
| 50 | |
| 51 | .globl _ftrace_call |
| 52 | _ftrace_call: |
| 53 | call _ftrace_stub |
| 54 | |
| 55 | # ifdef CONFIG_FUNCTION_GRAPH_TRACER |
| 56 | .globl _ftrace_graph_call |
| 57 | _ftrace_graph_call: |
| 58 | nop; /* jump _ftrace_graph_caller; */ |
| 59 | # endif |
| 60 | |
| 61 | /* restore state and get out of dodge */ |
| 62 | .Lfinish_trace: |
| 63 | rets = [sp++]; |
| 64 | r1 = [sp++]; |
| 65 | r0 = [sp++]; |
| 66 | r2 = [sp++]; |
| 67 | |
| 68 | .globl _ftrace_stub |
| 69 | _ftrace_stub: |
| 70 | rts; |
| 71 | ENDPROC(_ftrace_caller) |
| 72 | |
| 73 | #else |
| 74 | |
| 75 | /* See documentation for _ftrace_caller */ |
| 76 | ENTRY(__mcount) |
Mike Frysinger | 1c873be | 2009-06-09 07:25:09 -0400 | [diff] [blame] | 77 | /* save third function arg early so we can do testing below */ |
| 78 | [--sp] = r2; |
| 79 | |
| 80 | /* load the function pointer to the tracer */ |
| 81 | p0.l = _ftrace_trace_function; |
| 82 | p0.h = _ftrace_trace_function; |
| 83 | r3 = [p0]; |
| 84 | |
| 85 | /* optional micro optimization: don't call the stub tracer */ |
| 86 | r2.l = _ftrace_stub; |
| 87 | r2.h = _ftrace_stub; |
| 88 | cc = r2 == r3; |
| 89 | if ! cc jump .Ldo_trace; |
| 90 | |
Mike Frysinger | f507442 | 2010-07-21 09:13:02 -0400 | [diff] [blame] | 91 | # ifdef CONFIG_FUNCTION_GRAPH_TRACER |
Mike Frysinger | 1ee76d7 | 2009-06-10 04:45:29 -0400 | [diff] [blame] | 92 | /* if the ftrace_graph_return function pointer is not set to |
| 93 | * the ftrace_stub entry, call prepare_ftrace_return(). |
| 94 | */ |
| 95 | p0.l = _ftrace_graph_return; |
| 96 | p0.h = _ftrace_graph_return; |
| 97 | r3 = [p0]; |
| 98 | cc = r2 == r3; |
| 99 | if ! cc jump _ftrace_graph_caller; |
| 100 | |
| 101 | /* similarly, if the ftrace_graph_entry function pointer is not |
| 102 | * set to the ftrace_graph_entry_stub entry, ... |
| 103 | */ |
| 104 | p0.l = _ftrace_graph_entry; |
| 105 | p0.h = _ftrace_graph_entry; |
| 106 | r2.l = _ftrace_graph_entry_stub; |
| 107 | r2.h = _ftrace_graph_entry_stub; |
| 108 | r3 = [p0]; |
| 109 | cc = r2 == r3; |
| 110 | if ! cc jump _ftrace_graph_caller; |
Mike Frysinger | f507442 | 2010-07-21 09:13:02 -0400 | [diff] [blame] | 111 | # endif |
Mike Frysinger | 1ee76d7 | 2009-06-10 04:45:29 -0400 | [diff] [blame] | 112 | |
Mike Frysinger | 1c873be | 2009-06-09 07:25:09 -0400 | [diff] [blame] | 113 | r2 = [sp++]; |
| 114 | rts; |
| 115 | |
| 116 | .Ldo_trace: |
| 117 | |
| 118 | /* save first/second function arg and the return register */ |
| 119 | [--sp] = r0; |
| 120 | [--sp] = r1; |
| 121 | [--sp] = rets; |
| 122 | |
| 123 | /* setup the tracer function */ |
| 124 | p0 = r3; |
| 125 | |
Yi Li | 5bf9cbe | 2009-09-15 09:24:31 +0000 | [diff] [blame] | 126 | /* function_trace_call(unsigned long ip, unsigned long parent_ip): |
| 127 | * ip: this point was called by ... |
| 128 | * parent_ip: ... this function |
| 129 | * the ip itself will need adjusting for the mcount call |
Mike Frysinger | 1c873be | 2009-06-09 07:25:09 -0400 | [diff] [blame] | 130 | */ |
Yi Li | 5bf9cbe | 2009-09-15 09:24:31 +0000 | [diff] [blame] | 131 | r0 = rets; |
| 132 | r1 = [sp + 16]; /* skip the 4 local regs on stack */ |
| 133 | r0 += -MCOUNT_INSN_SIZE; |
Mike Frysinger | 1c873be | 2009-06-09 07:25:09 -0400 | [diff] [blame] | 134 | |
| 135 | /* call the tracer */ |
| 136 | call (p0); |
| 137 | |
| 138 | /* restore state and get out of dodge */ |
Mike Frysinger | 1ee76d7 | 2009-06-10 04:45:29 -0400 | [diff] [blame] | 139 | .Lfinish_trace: |
Mike Frysinger | 1c873be | 2009-06-09 07:25:09 -0400 | [diff] [blame] | 140 | rets = [sp++]; |
| 141 | r1 = [sp++]; |
| 142 | r0 = [sp++]; |
| 143 | r2 = [sp++]; |
| 144 | |
| 145 | .globl _ftrace_stub |
| 146 | _ftrace_stub: |
| 147 | rts; |
| 148 | ENDPROC(__mcount) |
Mike Frysinger | 1ee76d7 | 2009-06-10 04:45:29 -0400 | [diff] [blame] | 149 | |
Mike Frysinger | f507442 | 2010-07-21 09:13:02 -0400 | [diff] [blame] | 150 | #endif |
| 151 | |
Mike Frysinger | 1ee76d7 | 2009-06-10 04:45:29 -0400 | [diff] [blame] | 152 | #ifdef CONFIG_FUNCTION_GRAPH_TRACER |
| 153 | /* The prepare_ftrace_return() function is similar to the trace function |
| 154 | * except it takes a pointer to the location of the frompc. This is so |
| 155 | * the prepare_ftrace_return() can hijack it temporarily for probing |
| 156 | * purposes. |
| 157 | */ |
| 158 | ENTRY(_ftrace_graph_caller) |
Mike Frysinger | f507442 | 2010-07-21 09:13:02 -0400 | [diff] [blame] | 159 | # ifndef CONFIG_DYNAMIC_FTRACE |
Mike Frysinger | 1ee76d7 | 2009-06-10 04:45:29 -0400 | [diff] [blame] | 160 | /* save first/second function arg and the return register */ |
| 161 | [--sp] = r0; |
| 162 | [--sp] = r1; |
| 163 | [--sp] = rets; |
| 164 | |
Mike Frysinger | b73faf7 | 2010-01-22 07:59:32 -0500 | [diff] [blame] | 165 | /* prepare_ftrace_return(parent, self_addr, frame_pointer) */ |
| 166 | r0 = sp; /* unsigned long *parent */ |
| 167 | r1 = rets; /* unsigned long self_addr */ |
Mike Frysinger | f507442 | 2010-07-21 09:13:02 -0400 | [diff] [blame] | 168 | # else |
| 169 | r0 = sp; /* unsigned long *parent */ |
| 170 | r1 = [sp]; /* unsigned long self_addr */ |
| 171 | # endif |
| 172 | # ifdef CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST |
Mike Frysinger | b73faf7 | 2010-01-22 07:59:32 -0500 | [diff] [blame] | 173 | r2 = fp; /* unsigned long frame_pointer */ |
Mike Frysinger | f507442 | 2010-07-21 09:13:02 -0400 | [diff] [blame] | 174 | # endif |
Yi Li | 5bf9cbe | 2009-09-15 09:24:31 +0000 | [diff] [blame] | 175 | r0 += 16; /* skip the 4 local regs on stack */ |
Mike Frysinger | 1ee76d7 | 2009-06-10 04:45:29 -0400 | [diff] [blame] | 176 | r1 += -MCOUNT_INSN_SIZE; |
| 177 | call _prepare_ftrace_return; |
| 178 | |
| 179 | jump .Lfinish_trace; |
| 180 | ENDPROC(_ftrace_graph_caller) |
| 181 | |
| 182 | /* Undo the rewrite caused by ftrace_graph_caller(). The common function |
| 183 | * ftrace_return_to_handler() will return the original rets so we can |
| 184 | * restore it and be on our way. |
| 185 | */ |
| 186 | ENTRY(_return_to_handler) |
| 187 | /* make sure original return values are saved */ |
| 188 | [--sp] = p0; |
| 189 | [--sp] = r0; |
| 190 | [--sp] = r1; |
| 191 | |
| 192 | /* get original return address */ |
Mike Frysinger | f507442 | 2010-07-21 09:13:02 -0400 | [diff] [blame] | 193 | # ifdef CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST |
Mike Frysinger | b73faf7 | 2010-01-22 07:59:32 -0500 | [diff] [blame] | 194 | r0 = fp; /* Blackfin is sane, so omit this */ |
Mike Frysinger | f507442 | 2010-07-21 09:13:02 -0400 | [diff] [blame] | 195 | # endif |
Mike Frysinger | 1ee76d7 | 2009-06-10 04:45:29 -0400 | [diff] [blame] | 196 | call _ftrace_return_to_handler; |
| 197 | rets = r0; |
| 198 | |
| 199 | /* anomaly 05000371 - make sure we have at least three instructions |
| 200 | * between rets setting and the return |
| 201 | */ |
| 202 | r1 = [sp++]; |
| 203 | r0 = [sp++]; |
| 204 | p0 = [sp++]; |
| 205 | rts; |
| 206 | ENDPROC(_return_to_handler) |
| 207 | #endif |