Thomas Gleixner | d2912cb | 2019-06-04 10:11:33 +0200 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0-only |
Mischa Jonker | f46121b | 2013-01-18 15:12:24 +0530 | [diff] [blame] | 2 | /* |
| 3 | * kgdb support for ARC |
| 4 | * |
| 5 | * Copyright (C) 2012 Synopsys, Inc. (www.synopsys.com) |
Mischa Jonker | f46121b | 2013-01-18 15:12:24 +0530 | [diff] [blame] | 6 | */ |
| 7 | |
| 8 | #include <linux/kgdb.h> |
Vineet Gupta | 1540c85 | 2013-03-07 16:47:23 +0530 | [diff] [blame] | 9 | #include <linux/sched.h> |
Ingo Molnar | 68db0cf | 2017-02-08 18:51:37 +0100 | [diff] [blame] | 10 | #include <linux/sched/task_stack.h> |
Mischa Jonker | f46121b | 2013-01-18 15:12:24 +0530 | [diff] [blame] | 11 | #include <asm/disasm.h> |
| 12 | #include <asm/cacheflush.h> |
| 13 | |
| 14 | static void to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *kernel_regs, |
| 15 | struct callee_regs *cregs) |
| 16 | { |
| 17 | int regno; |
| 18 | |
| 19 | for (regno = 0; regno <= 26; regno++) |
| 20 | gdb_regs[_R0 + regno] = get_reg(regno, kernel_regs, cregs); |
| 21 | |
| 22 | for (regno = 27; regno < GDB_MAX_REGS; regno++) |
| 23 | gdb_regs[regno] = 0; |
| 24 | |
| 25 | gdb_regs[_FP] = kernel_regs->fp; |
| 26 | gdb_regs[__SP] = kernel_regs->sp; |
| 27 | gdb_regs[_BLINK] = kernel_regs->blink; |
| 28 | gdb_regs[_RET] = kernel_regs->ret; |
| 29 | gdb_regs[_STATUS32] = kernel_regs->status32; |
| 30 | gdb_regs[_LP_COUNT] = kernel_regs->lp_count; |
| 31 | gdb_regs[_LP_END] = kernel_regs->lp_end; |
| 32 | gdb_regs[_LP_START] = kernel_regs->lp_start; |
| 33 | gdb_regs[_BTA] = kernel_regs->bta; |
| 34 | gdb_regs[_STOP_PC] = kernel_regs->ret; |
| 35 | } |
| 36 | |
| 37 | static void from_gdb_regs(unsigned long *gdb_regs, struct pt_regs *kernel_regs, |
| 38 | struct callee_regs *cregs) |
| 39 | { |
| 40 | int regno; |
| 41 | |
| 42 | for (regno = 0; regno <= 26; regno++) |
| 43 | set_reg(regno, gdb_regs[regno + _R0], kernel_regs, cregs); |
| 44 | |
| 45 | kernel_regs->fp = gdb_regs[_FP]; |
| 46 | kernel_regs->sp = gdb_regs[__SP]; |
| 47 | kernel_regs->blink = gdb_regs[_BLINK]; |
| 48 | kernel_regs->ret = gdb_regs[_RET]; |
| 49 | kernel_regs->status32 = gdb_regs[_STATUS32]; |
| 50 | kernel_regs->lp_count = gdb_regs[_LP_COUNT]; |
| 51 | kernel_regs->lp_end = gdb_regs[_LP_END]; |
| 52 | kernel_regs->lp_start = gdb_regs[_LP_START]; |
| 53 | kernel_regs->bta = gdb_regs[_BTA]; |
| 54 | } |
| 55 | |
| 56 | |
| 57 | void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *kernel_regs) |
| 58 | { |
| 59 | to_gdb_regs(gdb_regs, kernel_regs, (struct callee_regs *) |
| 60 | current->thread.callee_reg); |
| 61 | } |
| 62 | |
| 63 | void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *kernel_regs) |
| 64 | { |
| 65 | from_gdb_regs(gdb_regs, kernel_regs, (struct callee_regs *) |
| 66 | current->thread.callee_reg); |
| 67 | } |
| 68 | |
| 69 | void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, |
| 70 | struct task_struct *task) |
| 71 | { |
| 72 | if (task) |
| 73 | to_gdb_regs(gdb_regs, task_pt_regs(task), |
| 74 | (struct callee_regs *) task->thread.callee_reg); |
| 75 | } |
| 76 | |
| 77 | struct single_step_data_t { |
| 78 | uint16_t opcode[2]; |
| 79 | unsigned long address[2]; |
| 80 | int is_branch; |
| 81 | int armed; |
| 82 | } single_step_data; |
| 83 | |
| 84 | static void undo_single_step(struct pt_regs *regs) |
| 85 | { |
| 86 | if (single_step_data.armed) { |
| 87 | int i; |
| 88 | |
| 89 | for (i = 0; i < (single_step_data.is_branch ? 2 : 1); i++) { |
| 90 | memcpy((void *) single_step_data.address[i], |
| 91 | &single_step_data.opcode[i], |
| 92 | BREAK_INSTR_SIZE); |
| 93 | |
| 94 | flush_icache_range(single_step_data.address[i], |
| 95 | single_step_data.address[i] + |
| 96 | BREAK_INSTR_SIZE); |
| 97 | } |
| 98 | single_step_data.armed = 0; |
| 99 | } |
| 100 | } |
| 101 | |
| 102 | static void place_trap(unsigned long address, void *save) |
| 103 | { |
| 104 | memcpy(save, (void *) address, BREAK_INSTR_SIZE); |
| 105 | memcpy((void *) address, &arch_kgdb_ops.gdb_bpt_instr, |
| 106 | BREAK_INSTR_SIZE); |
| 107 | flush_icache_range(address, address + BREAK_INSTR_SIZE); |
| 108 | } |
| 109 | |
| 110 | static void do_single_step(struct pt_regs *regs) |
| 111 | { |
| 112 | single_step_data.is_branch = disasm_next_pc((unsigned long) |
| 113 | regs->ret, regs, (struct callee_regs *) |
| 114 | current->thread.callee_reg, |
| 115 | &single_step_data.address[0], |
| 116 | &single_step_data.address[1]); |
| 117 | |
| 118 | place_trap(single_step_data.address[0], &single_step_data.opcode[0]); |
| 119 | |
| 120 | if (single_step_data.is_branch) { |
| 121 | place_trap(single_step_data.address[1], |
| 122 | &single_step_data.opcode[1]); |
| 123 | } |
| 124 | |
| 125 | single_step_data.armed++; |
| 126 | } |
| 127 | |
| 128 | int kgdb_arch_handle_exception(int e_vector, int signo, int err_code, |
| 129 | char *remcomInBuffer, char *remcomOutBuffer, |
| 130 | struct pt_regs *regs) |
| 131 | { |
| 132 | unsigned long addr; |
| 133 | char *ptr; |
| 134 | |
| 135 | undo_single_step(regs); |
| 136 | |
| 137 | switch (remcomInBuffer[0]) { |
| 138 | case 's': |
| 139 | case 'c': |
| 140 | ptr = &remcomInBuffer[1]; |
| 141 | if (kgdb_hex2long(&ptr, &addr)) |
| 142 | regs->ret = addr; |
| 143 | |
| 144 | case 'D': |
| 145 | case 'k': |
| 146 | atomic_set(&kgdb_cpu_doing_single_step, -1); |
| 147 | |
| 148 | if (remcomInBuffer[0] == 's') { |
| 149 | do_single_step(regs); |
| 150 | atomic_set(&kgdb_cpu_doing_single_step, |
| 151 | smp_processor_id()); |
| 152 | } |
| 153 | |
| 154 | return 0; |
| 155 | } |
| 156 | return -1; |
| 157 | } |
| 158 | |
Mischa Jonker | f46121b | 2013-01-18 15:12:24 +0530 | [diff] [blame] | 159 | int kgdb_arch_init(void) |
| 160 | { |
| 161 | single_step_data.armed = 0; |
| 162 | return 0; |
| 163 | } |
| 164 | |
Vineet Gupta | 38a9ff6 | 2013-06-12 15:13:40 +0530 | [diff] [blame] | 165 | void kgdb_trap(struct pt_regs *regs) |
Mischa Jonker | f46121b | 2013-01-18 15:12:24 +0530 | [diff] [blame] | 166 | { |
| 167 | /* trap_s 3 is used for breakpoints that overwrite existing |
| 168 | * instructions, while trap_s 4 is used for compiled breakpoints. |
| 169 | * |
| 170 | * with trap_s 3 breakpoints the original instruction needs to be |
| 171 | * restored and continuation needs to start at the location of the |
| 172 | * breakpoint. |
| 173 | * |
| 174 | * with trap_s 4 (compiled) breakpoints, continuation needs to |
| 175 | * start after the breakpoint. |
| 176 | */ |
Vineet Gupta | 502a0c7 | 2013-06-11 18:56:54 +0530 | [diff] [blame] | 177 | if (regs->ecr_param == 3) |
Mischa Jonker | f46121b | 2013-01-18 15:12:24 +0530 | [diff] [blame] | 178 | instruction_pointer(regs) -= BREAK_INSTR_SIZE; |
| 179 | |
| 180 | kgdb_handle_exception(1, SIGTRAP, 0, regs); |
| 181 | } |
| 182 | |
| 183 | void kgdb_arch_exit(void) |
| 184 | { |
| 185 | } |
| 186 | |
| 187 | void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip) |
| 188 | { |
| 189 | instruction_pointer(regs) = ip; |
| 190 | } |
| 191 | |
Douglas Anderson | 3cd99ac | 2018-12-04 19:38:26 -0800 | [diff] [blame] | 192 | void kgdb_call_nmi_hook(void *ignored) |
Chen Gang | 3d01c1c | 2013-10-24 11:50:09 +0800 | [diff] [blame] | 193 | { |
Douglas Anderson | 3cd99ac | 2018-12-04 19:38:26 -0800 | [diff] [blame] | 194 | /* Default implementation passes get_irq_regs() but we don't */ |
Chen Gang | 3d01c1c | 2013-10-24 11:50:09 +0800 | [diff] [blame] | 195 | kgdb_nmicallback(raw_smp_processor_id(), NULL); |
| 196 | } |
| 197 | |
Christophe Leroy | cc02829 | 2018-12-06 20:07:40 +0000 | [diff] [blame] | 198 | const struct kgdb_arch arch_kgdb_ops = { |
Mischa Jonker | f46121b | 2013-01-18 15:12:24 +0530 | [diff] [blame] | 199 | /* breakpoint instruction: TRAP_S 0x3 */ |
| 200 | #ifdef CONFIG_CPU_BIG_ENDIAN |
| 201 | .gdb_bpt_instr = {0x78, 0x7e}, |
| 202 | #else |
| 203 | .gdb_bpt_instr = {0x7e, 0x78}, |
| 204 | #endif |
| 205 | }; |