arch/sparc/kernel/kgdb_64.c

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