Tony Lu | a61fd5e | 2013-08-09 13:26:09 -0400 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2012 Tilera Corporation. All Rights Reserved. |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or |
| 5 | * modify it under the terms of the GNU General Public License |
| 6 | * as published by the Free Software Foundation, version 2. |
| 7 | * |
| 8 | * This program is distributed in the hope that it will be useful, but |
| 9 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
| 10 | * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or |
| 11 | * NON INFRINGEMENT. See the GNU General Public License for |
| 12 | * more details. |
| 13 | * |
| 14 | * TILE-Gx specific ftrace support |
| 15 | */ |
| 16 | |
| 17 | #include <linux/ftrace.h> |
| 18 | #include <linux/uaccess.h> |
| 19 | |
| 20 | #include <asm/cacheflush.h> |
| 21 | #include <asm/ftrace.h> |
| 22 | #include <asm/sections.h> |
Zhigang Lu | 65a792e | 2015-09-30 10:11:45 +0800 | [diff] [blame] | 23 | #include <asm/insn.h> |
Tony Lu | a61fd5e | 2013-08-09 13:26:09 -0400 | [diff] [blame] | 24 | |
| 25 | #include <arch/opcode.h> |
| 26 | |
| 27 | #ifdef CONFIG_DYNAMIC_FTRACE |
| 28 | |
Tony Lu | a61fd5e | 2013-08-09 13:26:09 -0400 | [diff] [blame] | 29 | static int machine_stopped __read_mostly; |
| 30 | |
| 31 | int ftrace_arch_code_modify_prepare(void) |
| 32 | { |
| 33 | machine_stopped = 1; |
| 34 | return 0; |
| 35 | } |
| 36 | |
| 37 | int ftrace_arch_code_modify_post_process(void) |
| 38 | { |
| 39 | flush_icache_range(0, CHIP_L1I_CACHE_SIZE()); |
| 40 | machine_stopped = 0; |
| 41 | return 0; |
| 42 | } |
| 43 | |
| 44 | /* |
| 45 | * Put { move r10, lr; jal ftrace_caller } in a bundle, this lets dynamic |
| 46 | * tracer just add one cycle overhead to every kernel function when disabled. |
| 47 | */ |
| 48 | static unsigned long ftrace_gen_branch(unsigned long pc, unsigned long addr, |
| 49 | bool link) |
| 50 | { |
| 51 | tilegx_bundle_bits opcode_x0, opcode_x1; |
| 52 | long pcrel_by_instr = (addr - pc) >> TILEGX_LOG2_BUNDLE_SIZE_IN_BYTES; |
| 53 | |
| 54 | if (link) { |
| 55 | /* opcode: jal addr */ |
| 56 | opcode_x1 = |
| 57 | create_Opcode_X1(JUMP_OPCODE_X1) | |
| 58 | create_JumpOpcodeExtension_X1(JAL_JUMP_OPCODE_X1) | |
| 59 | create_JumpOff_X1(pcrel_by_instr); |
| 60 | } else { |
| 61 | /* opcode: j addr */ |
| 62 | opcode_x1 = |
| 63 | create_Opcode_X1(JUMP_OPCODE_X1) | |
| 64 | create_JumpOpcodeExtension_X1(J_JUMP_OPCODE_X1) | |
| 65 | create_JumpOff_X1(pcrel_by_instr); |
| 66 | } |
| 67 | |
Tony Lu | 437d3e1 | 2015-03-27 14:46:38 -0400 | [diff] [blame] | 68 | /* |
| 69 | * Also put { move r10, lr; jal ftrace_stub } in a bundle, which |
| 70 | * is used to replace the instruction in address ftrace_call. |
| 71 | */ |
| 72 | if (addr == FTRACE_ADDR || addr == (unsigned long)ftrace_stub) { |
Tony Lu | a61fd5e | 2013-08-09 13:26:09 -0400 | [diff] [blame] | 73 | /* opcode: or r10, lr, zero */ |
| 74 | opcode_x0 = |
| 75 | create_Dest_X0(10) | |
| 76 | create_SrcA_X0(TREG_LR) | |
| 77 | create_SrcB_X0(TREG_ZERO) | |
| 78 | create_RRROpcodeExtension_X0(OR_RRR_0_OPCODE_X0) | |
| 79 | create_Opcode_X0(RRR_0_OPCODE_X0); |
| 80 | } else { |
| 81 | /* opcode: fnop */ |
| 82 | opcode_x0 = |
| 83 | create_UnaryOpcodeExtension_X0(FNOP_UNARY_OPCODE_X0) | |
| 84 | create_RRROpcodeExtension_X0(UNARY_RRR_0_OPCODE_X0) | |
| 85 | create_Opcode_X0(RRR_0_OPCODE_X0); |
| 86 | } |
| 87 | |
| 88 | return opcode_x1 | opcode_x0; |
| 89 | } |
| 90 | |
| 91 | static unsigned long ftrace_nop_replace(struct dyn_ftrace *rec) |
| 92 | { |
| 93 | return NOP(); |
| 94 | } |
| 95 | |
| 96 | static unsigned long ftrace_call_replace(unsigned long pc, unsigned long addr) |
| 97 | { |
| 98 | return ftrace_gen_branch(pc, addr, true); |
| 99 | } |
| 100 | |
| 101 | static int ftrace_modify_code(unsigned long pc, unsigned long old, |
| 102 | unsigned long new) |
| 103 | { |
| 104 | unsigned long pc_wr; |
| 105 | |
| 106 | /* Check if the address is in kernel text space and module space. */ |
| 107 | if (!kernel_text_address(pc)) |
| 108 | return -EINVAL; |
| 109 | |
| 110 | /* Operate on writable kernel text mapping. */ |
Zhigang Lu | f419e6f | 2015-09-30 09:53:47 +0800 | [diff] [blame] | 111 | pc_wr = ktext_writable_addr(pc); |
Tony Lu | a61fd5e | 2013-08-09 13:26:09 -0400 | [diff] [blame] | 112 | |
| 113 | if (probe_kernel_write((void *)pc_wr, &new, MCOUNT_INSN_SIZE)) |
| 114 | return -EPERM; |
| 115 | |
| 116 | smp_wmb(); |
| 117 | |
| 118 | if (!machine_stopped && num_online_cpus() > 1) |
| 119 | flush_icache_range(pc, pc + MCOUNT_INSN_SIZE); |
| 120 | |
| 121 | return 0; |
| 122 | } |
| 123 | |
| 124 | int ftrace_update_ftrace_func(ftrace_func_t func) |
| 125 | { |
| 126 | unsigned long pc, old; |
| 127 | unsigned long new; |
| 128 | int ret; |
| 129 | |
| 130 | pc = (unsigned long)&ftrace_call; |
| 131 | memcpy(&old, &ftrace_call, MCOUNT_INSN_SIZE); |
| 132 | new = ftrace_call_replace(pc, (unsigned long)func); |
| 133 | |
| 134 | ret = ftrace_modify_code(pc, old, new); |
| 135 | |
| 136 | return ret; |
| 137 | } |
| 138 | |
| 139 | int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) |
| 140 | { |
| 141 | unsigned long new, old; |
| 142 | unsigned long ip = rec->ip; |
| 143 | |
| 144 | old = ftrace_nop_replace(rec); |
| 145 | new = ftrace_call_replace(ip, addr); |
| 146 | |
| 147 | return ftrace_modify_code(rec->ip, old, new); |
| 148 | } |
| 149 | |
| 150 | int ftrace_make_nop(struct module *mod, |
| 151 | struct dyn_ftrace *rec, unsigned long addr) |
| 152 | { |
| 153 | unsigned long ip = rec->ip; |
| 154 | unsigned long old; |
| 155 | unsigned long new; |
| 156 | int ret; |
| 157 | |
| 158 | old = ftrace_call_replace(ip, addr); |
| 159 | new = ftrace_nop_replace(rec); |
| 160 | ret = ftrace_modify_code(ip, old, new); |
| 161 | |
| 162 | return ret; |
| 163 | } |
| 164 | |
Jiri Slaby | 3a36cb1 | 2014-02-24 19:59:59 +0100 | [diff] [blame] | 165 | int __init ftrace_dyn_arch_init(void) |
Tony Lu | a61fd5e | 2013-08-09 13:26:09 -0400 | [diff] [blame] | 166 | { |
Tony Lu | a61fd5e | 2013-08-09 13:26:09 -0400 | [diff] [blame] | 167 | return 0; |
| 168 | } |
| 169 | #endif /* CONFIG_DYNAMIC_FTRACE */ |
| 170 | |
| 171 | #ifdef CONFIG_FUNCTION_GRAPH_TRACER |
| 172 | void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, |
| 173 | unsigned long frame_pointer) |
| 174 | { |
| 175 | unsigned long return_hooker = (unsigned long) &return_to_handler; |
| 176 | struct ftrace_graph_ent trace; |
| 177 | unsigned long old; |
| 178 | int err; |
| 179 | |
| 180 | if (unlikely(atomic_read(¤t->tracing_graph_pause))) |
| 181 | return; |
| 182 | |
| 183 | old = *parent; |
| 184 | *parent = return_hooker; |
| 185 | |
| 186 | err = ftrace_push_return_trace(old, self_addr, &trace.depth, |
| 187 | frame_pointer); |
| 188 | if (err == -EBUSY) { |
| 189 | *parent = old; |
| 190 | return; |
| 191 | } |
| 192 | |
| 193 | trace.func = self_addr; |
| 194 | |
| 195 | /* Only trace if the calling function expects to */ |
| 196 | if (!ftrace_graph_entry(&trace)) { |
| 197 | current->curr_ret_stack--; |
| 198 | *parent = old; |
| 199 | } |
| 200 | } |
| 201 | |
| 202 | #ifdef CONFIG_DYNAMIC_FTRACE |
| 203 | extern unsigned long ftrace_graph_call; |
| 204 | |
| 205 | static int __ftrace_modify_caller(unsigned long *callsite, |
| 206 | void (*func) (void), bool enable) |
| 207 | { |
| 208 | unsigned long caller_fn = (unsigned long) func; |
| 209 | unsigned long pc = (unsigned long) callsite; |
| 210 | unsigned long branch = ftrace_gen_branch(pc, caller_fn, false); |
| 211 | unsigned long nop = NOP(); |
| 212 | unsigned long old = enable ? nop : branch; |
| 213 | unsigned long new = enable ? branch : nop; |
| 214 | |
| 215 | return ftrace_modify_code(pc, old, new); |
| 216 | } |
| 217 | |
| 218 | static int ftrace_modify_graph_caller(bool enable) |
| 219 | { |
| 220 | int ret; |
| 221 | |
| 222 | ret = __ftrace_modify_caller(&ftrace_graph_call, |
| 223 | ftrace_graph_caller, |
| 224 | enable); |
| 225 | |
| 226 | return ret; |
| 227 | } |
| 228 | |
| 229 | int ftrace_enable_ftrace_graph_caller(void) |
| 230 | { |
| 231 | return ftrace_modify_graph_caller(true); |
| 232 | } |
| 233 | |
| 234 | int ftrace_disable_ftrace_graph_caller(void) |
| 235 | { |
| 236 | return ftrace_modify_graph_caller(false); |
| 237 | } |
| 238 | #endif /* CONFIG_DYNAMIC_FTRACE */ |
| 239 | #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ |