1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * PA-RISC KGDB support 4 * 5 * Copyright (c) 2019 Sven Schnelle <svens@stackframe.org> 6 * 7 */ 8 9 #include <linux/kgdb.h> 10 #include <linux/string.h> 11 #include <linux/sched.h> 12 #include <linux/notifier.h> 13 #include <linux/kdebug.h> 14 #include <linux/uaccess.h> 15 #include <asm/ptrace.h> 16 #include <asm/traps.h> 17 #include <asm/processor.h> 18 #include <asm/patch.h> 19 #include <asm/cacheflush.h> 20 21 const struct kgdb_arch arch_kgdb_ops = { 22 .gdb_bpt_instr = { 0x03, 0xff, 0xa0, 0x1f } 23 }; 24 25 static int __kgdb_notify(struct die_args *args, unsigned long cmd) 26 { 27 struct pt_regs *regs = args->regs; 28 29 if (kgdb_handle_exception(1, args->signr, cmd, regs)) 30 return NOTIFY_DONE; 31 return NOTIFY_STOP; 32 } 33 34 static int kgdb_notify(struct notifier_block *self, 35 unsigned long cmd, void *ptr) 36 { 37 unsigned long flags; 38 int ret; 39 40 local_irq_save(flags); 41 ret = __kgdb_notify(ptr, cmd); 42 local_irq_restore(flags); 43 44 return ret; 45 } 46 47 static struct notifier_block kgdb_notifier = { 48 .notifier_call = kgdb_notify, 49 .priority = -INT_MAX, 50 }; 51 52 int kgdb_arch_init(void) 53 { 54 return register_die_notifier(&kgdb_notifier); 55 } 56 57 void kgdb_arch_exit(void) 58 { 59 unregister_die_notifier(&kgdb_notifier); 60 } 61 62 void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs) 63 { 64 struct parisc_gdb_regs *gr = (struct parisc_gdb_regs *)gdb_regs; 65 66 memset(gr, 0, sizeof(struct parisc_gdb_regs)); 67 68 memcpy(gr->gpr, regs->gr, sizeof(gr->gpr)); 69 memcpy(gr->fr, regs->fr, sizeof(gr->fr)); 70 71 gr->sr0 = regs->sr[0]; 72 gr->sr1 = regs->sr[1]; 73 gr->sr2 = regs->sr[2]; 74 gr->sr3 = regs->sr[3]; 75 gr->sr4 = regs->sr[4]; 76 gr->sr5 = regs->sr[5]; 77 gr->sr6 = regs->sr[6]; 78 gr->sr7 = regs->sr[7]; 79 80 gr->sar = regs->sar; 81 gr->iir = regs->iir; 82 gr->isr = regs->isr; 83 gr->ior = regs->ior; 84 gr->ipsw = regs->ipsw; 85 gr->cr27 = regs->cr27; 86 87 gr->iaoq_f = regs->iaoq[0]; 88 gr->iasq_f = regs->iasq[0]; 89 90 gr->iaoq_b = regs->iaoq[1]; 91 gr->iasq_b = regs->iasq[1]; 92 } 93 94 void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs) 95 { 96 struct parisc_gdb_regs *gr = (struct parisc_gdb_regs *)gdb_regs; 97 98 99 memcpy(regs->gr, gr->gpr, sizeof(regs->gr)); 100 memcpy(regs->fr, gr->fr, sizeof(regs->fr)); 101 102 regs->sr[0] = gr->sr0; 103 regs->sr[1] = gr->sr1; 104 regs->sr[2] = gr->sr2; 105 regs->sr[3] = gr->sr3; 106 regs->sr[4] = gr->sr4; 107 regs->sr[5] = gr->sr5; 108 regs->sr[6] = gr->sr6; 109 regs->sr[7] = gr->sr7; 110 111 regs->sar = gr->sar; 112 regs->iir = gr->iir; 113 regs->isr = gr->isr; 114 regs->ior = gr->ior; 115 regs->ipsw = gr->ipsw; 116 regs->cr27 = gr->cr27; 117 118 regs->iaoq[0] = gr->iaoq_f; 119 regs->iasq[0] = gr->iasq_f; 120 121 regs->iaoq[1] = gr->iaoq_b; 122 regs->iasq[1] = gr->iasq_b; 123 } 124 125 void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, 126 struct task_struct *task) 127 { 128 struct pt_regs *regs = task_pt_regs(task); 129 unsigned long gr30, iaoq; 130 131 gr30 = regs->gr[30]; 132 iaoq = regs->iaoq[0]; 133 134 regs->gr[30] = regs->ksp; 135 regs->iaoq[0] = regs->kpc; 136 pt_regs_to_gdb_regs(gdb_regs, regs); 137 138 regs->gr[30] = gr30; 139 regs->iaoq[0] = iaoq; 140 141 } 142 143 static void step_instruction_queue(struct pt_regs *regs) 144 { 145 regs->iaoq[0] = regs->iaoq[1]; 146 regs->iaoq[1] += 4; 147 } 148 149 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip) 150 { 151 regs->iaoq[0] = ip; 152 regs->iaoq[1] = ip + 4; 153 } 154 155 int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt) 156 { 157 int ret = copy_from_kernel_nofault(bpt->saved_instr, 158 (char *)bpt->bpt_addr, BREAK_INSTR_SIZE); 159 if (ret) 160 return ret; 161 162 __patch_text((void *)bpt->bpt_addr, 163 *(unsigned int *)&arch_kgdb_ops.gdb_bpt_instr); 164 return ret; 165 } 166 167 int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt) 168 { 169 __patch_text((void *)bpt->bpt_addr, *(unsigned int *)&bpt->saved_instr); 170 return 0; 171 } 172 173 int kgdb_arch_handle_exception(int trap, int signo, 174 int err_code, char *inbuf, char *outbuf, 175 struct pt_regs *regs) 176 { 177 unsigned long addr; 178 char *p = inbuf + 1; 179 180 switch (inbuf[0]) { 181 case 'D': 182 case 'c': 183 case 'k': 184 kgdb_contthread = NULL; 185 kgdb_single_step = 0; 186 187 if (kgdb_hex2long(&p, &addr)) 188 kgdb_arch_set_pc(regs, addr); 189 else if (trap == 9 && regs->iir == 190 PARISC_KGDB_COMPILED_BREAK_INSN) 191 step_instruction_queue(regs); 192 return 0; 193 case 's': 194 kgdb_single_step = 1; 195 if (kgdb_hex2long(&p, &addr)) { 196 kgdb_arch_set_pc(regs, addr); 197 } else if (trap == 9 && regs->iir == 198 PARISC_KGDB_COMPILED_BREAK_INSN) { 199 step_instruction_queue(regs); 200 mtctl(-1, 0); 201 } else { 202 mtctl(0, 0); 203 } 204 regs->gr[0] |= PSW_R; 205 return 0; 206 207 } 208 return -1; 209 } 210