linux/arch/parisc/kernel/kgdb.c
<<
>>
Prefs
   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
  21const struct kgdb_arch arch_kgdb_ops = {
  22        .gdb_bpt_instr = { 0x03, 0xff, 0xa0, 0x1f }
  23};
  24
  25static 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
  34static 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
  47static struct notifier_block kgdb_notifier = {
  48        .notifier_call  = kgdb_notify,
  49        .priority       = -INT_MAX,
  50};
  51
  52int kgdb_arch_init(void)
  53{
  54        return register_die_notifier(&kgdb_notifier);
  55}
  56
  57void kgdb_arch_exit(void)
  58{
  59        unregister_die_notifier(&kgdb_notifier);
  60}
  61
  62void 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
  94void 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
 125void 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
 143static void step_instruction_queue(struct pt_regs *regs)
 144{
 145        regs->iaoq[0] = regs->iaoq[1];
 146        regs->iaoq[1] += 4;
 147}
 148
 149void 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
 155int 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
 167int 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
 173int 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