arch/sparc/kernel/kgdb_64.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* kgdb.c: KGDB support for 64-bit sparc.
   3  *
   4  * Copyright (C) 2008 David S. Miller <davem@davemloft.net>
   5  */
   6
   7 #include <linux/kgdb.h>
   8 #include <linux/kdebug.h>
   9 #include <linux/ftrace.h>
  10 #include <linux/context_tracking.h>
  11
  12 #include <asm/cacheflush.h>
  13 #include <asm/kdebug.h>
  14 #include <asm/ptrace.h>
  15 #include <asm/irq.h>
  16
  17 #include "kernel.h"
  18
  19 void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
  20 {
  21         struct reg_window *win;
  22         int i;
  23
  24         gdb_regs[GDB_G0] = 0;
  25         for (i = 0; i < 15; i++)
  26                 gdb_regs[GDB_G1 + i] = regs->u_regs[UREG_G1 + i];
  27
  28         win = (struct reg_window *) (regs->u_regs[UREG_FP] + STACK_BIAS);
  29         for (i = 0; i < 8; i++)
  30                 gdb_regs[GDB_L0 + i] = win->locals[i];
  31         for (i = 0; i < 8; i++)
  32                 gdb_regs[GDB_I0 + i] = win->ins[i];
  33
  34         for (i = GDB_F0; i <= GDB_F62; i++)
  35                 gdb_regs[i] = 0;
  36
  37         gdb_regs[GDB_PC] = regs->tpc;
  38         gdb_regs[GDB_NPC] = regs->tnpc;
  39         gdb_regs[GDB_STATE] = regs->tstate;
  40         gdb_regs[GDB_FSR] = 0;
  41         gdb_regs[GDB_FPRS] = 0;
  42         gdb_regs[GDB_Y] = regs->y;
  43 }
  44
  45 void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
  46 {
  47         struct thread_info *t = task_thread_info(p);
  48         extern unsigned int switch_to_pc;
  49         extern unsigned int ret_from_fork;
  50         struct reg_window *win;
  51         unsigned long pc, cwp;
  52         int i;
  53
  54         for (i = GDB_G0; i < GDB_G6; i++)
  55                 gdb_regs[i] = 0;
  56         gdb_regs[GDB_G6] = (unsigned long) t;
  57         gdb_regs[GDB_G7] = (unsigned long) p;
  58         for (i = GDB_O0; i < GDB_SP; i++)
  59                 gdb_regs[i] = 0;
  60         gdb_regs[GDB_SP] = t->ksp;
  61         gdb_regs[GDB_O7] = 0;
  62
  63         win = (struct reg_window *) (t->ksp + STACK_BIAS);
  64         for (i = 0; i < 8; i++)
  65                 gdb_regs[GDB_L0 + i] = win->locals[i];
  66         for (i = 0; i < 8; i++)
  67                 gdb_regs[GDB_I0 + i] = win->ins[i];
  68
  69         for (i = GDB_F0; i <= GDB_F62; i++)
  70                 gdb_regs[i] = 0;
  71
  72         if (t->new_child)
  73                 pc = (unsigned long) &ret_from_fork;
  74         else
  75                 pc = (unsigned long) &switch_to_pc;
  76
  77         gdb_regs[GDB_PC] = pc;
  78         gdb_regs[GDB_NPC] = pc + 4;
  79
  80         cwp = __thread_flag_byte_ptr(t)[TI_FLAG_BYTE_CWP];
  81
  82         gdb_regs[GDB_STATE] = (TSTATE_PRIV | TSTATE_IE | cwp);
  83         gdb_regs[GDB_FSR] = 0;
  84         gdb_regs[GDB_FPRS] = 0;
  85         gdb_regs[GDB_Y] = 0;
  86 }
  87
  88 void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
  89 {
  90         struct reg_window *win;
  91         int i;
  92
  93         for (i = 0; i < 15; i++)
  94                 regs->u_regs[UREG_G1 + i] = gdb_regs[GDB_G1 + i];
  95
  96         /* If the TSTATE register is changing, we have to preserve
  97          * the CWP field, otherwise window save/restore explodes.
  98          */
  99         if (regs->tstate != gdb_regs[GDB_STATE]) {
 100                 unsigned long cwp = regs->tstate & TSTATE_CWP;
 101
 102                 regs->tstate = (gdb_regs[GDB_STATE] & ~TSTATE_CWP) | cwp;
 103         }
 104
 105         regs->tpc = gdb_regs[GDB_PC];
 106         regs->tnpc = gdb_regs[GDB_NPC];
 107         regs->y = gdb_regs[GDB_Y];
 108
 109         win = (struct reg_window *) (regs->u_regs[UREG_FP] + STACK_BIAS);
 110         for (i = 0; i < 8; i++)
 111                 win->locals[i] = gdb_regs[GDB_L0 + i];
 112         for (i = 0; i < 8; i++)
 113                 win->ins[i] = gdb_regs[GDB_I0 + i];
 114 }
 115
 116 #ifdef CONFIG_SMP
 117 void __irq_entry smp_kgdb_capture_client(int irq, struct pt_regs *regs)
 118 {
 119         unsigned long flags;
 120
 121         __asm__ __volatile__("rdpr      %%pstate, %0\n\t"
 122                              "wrpr      %0, %1, %%pstate"
 123                              : "=r" (flags)
 124                              : "i" (PSTATE_IE));
 125
 126         flushw_all();
 127
 128         if (atomic_read(&kgdb_active) != -1)
 129                 kgdb_nmicallback(raw_smp_processor_id(), regs);
 130
 131         __asm__ __volatile__("wrpr      %0, 0, %%pstate"
 132                              : : "r" (flags));
 133 }
 134 #endif
 135
 136 int kgdb_arch_handle_exception(int e_vector, int signo, int err_code,
 137                                char *remcomInBuffer, char *remcomOutBuffer,
 138                                struct pt_regs *linux_regs)
 139 {
 140         unsigned long addr;
 141         char *ptr;
 142
 143         switch (remcomInBuffer[0]) {
 144         case 'c':
 145                 /* try to read optional parameter, pc unchanged if no parm */
 146                 ptr = &remcomInBuffer[1];
 147                 if (kgdb_hex2long(&ptr, &addr)) {
 148                         linux_regs->tpc = addr;
 149                         linux_regs->tnpc = addr + 4;
 150                 }
 151                 /* fall through */
 152
 153         case 'D':
 154         case 'k':
 155                 if (linux_regs->tpc == (unsigned long) arch_kgdb_breakpoint) {
 156                         linux_regs->tpc = linux_regs->tnpc;
 157                         linux_regs->tnpc += 4;
 158                 }
 159                 return 0;
 160         }
 161         return -1;
 162 }
 163
 164 asmlinkage void kgdb_trap(unsigned long trap_level, struct pt_regs *regs)
 165 {
 166         enum ctx_state prev_state = exception_enter();
 167         unsigned long flags;
 168
 169         if (user_mode(regs)) {
 170                 bad_trap(regs, trap_level);
 171                 goto out;
 172         }
 173
 174         flushw_all();
 175
 176         local_irq_save(flags);
 177         kgdb_handle_exception(0x172, SIGTRAP, 0, regs);
 178         local_irq_restore(flags);
 179 out:
 180         exception_exit(prev_state);
 181 }
 182
 183 int kgdb_arch_init(void)
 184 {
 185         return 0;
 186 }
 187
 188 void kgdb_arch_exit(void)
 189 {
 190 }
 191
 192 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip)
 193 {
 194         regs->tpc = ip;
 195         regs->tnpc = regs->tpc + 4;
 196 }
 197
 198 const struct kgdb_arch arch_kgdb_ops = {
 199         /* Breakpoint instruction: ta 0x72 */
 200         .gdb_bpt_instr          = { 0x91, 0xd0, 0x20, 0x72 },
 201 };