arch/sparc64/kernel/kgdb.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
   9 #include <asm/kdebug.h>
  10 #include <asm/ptrace.h>
  11 #include <asm/irq.h>
  12
  13 void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
  14 {
  15         struct reg_window *win;
  16         int i;
  17
  18         gdb_regs[GDB_G0] = 0;
  19         for (i = 0; i < 15; i++)
  20                 gdb_regs[GDB_G1 + i] = regs->u_regs[UREG_G1 + i];
  21
  22         win = (struct reg_window *) (regs->u_regs[UREG_FP] + STACK_BIAS);
  23         for (i = 0; i < 8; i++)
  24                 gdb_regs[GDB_L0 + i] = win->locals[i];
  25         for (i = 0; i < 8; i++)
  26                 gdb_regs[GDB_I0 + i] = win->ins[i];
  27
  28         for (i = GDB_F0; i <= GDB_F62; i++)
  29                 gdb_regs[i] = 0;
  30
  31         gdb_regs[GDB_PC] = regs->tpc;
  32         gdb_regs[GDB_NPC] = regs->tnpc;
  33         gdb_regs[GDB_STATE] = regs->tstate;
  34         gdb_regs[GDB_FSR] = 0;
  35         gdb_regs[GDB_FPRS] = 0;
  36         gdb_regs[GDB_Y] = regs->y;
  37 }
  38
  39 void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
  40 {
  41         struct thread_info *t = task_thread_info(p);
  42         extern unsigned int switch_to_pc;
  43         extern unsigned int ret_from_syscall;
  44         struct reg_window *win;
  45         unsigned long pc, cwp;
  46         int i;
  47
  48         for (i = GDB_G0; i < GDB_G6; i++)
  49                 gdb_regs[i] = 0;
  50         gdb_regs[GDB_G6] = (unsigned long) t;
  51         gdb_regs[GDB_G7] = (unsigned long) p;
  52         for (i = GDB_O0; i < GDB_SP; i++)
  53                 gdb_regs[i] = 0;
  54         gdb_regs[GDB_SP] = t->ksp;
  55         gdb_regs[GDB_O7] = 0;
  56
  57         win = (struct reg_window *) (t->ksp + STACK_BIAS);
  58         for (i = 0; i < 8; i++)
  59                 gdb_regs[GDB_L0 + i] = win->locals[i];
  60         for (i = 0; i < 8; i++)
  61                 gdb_regs[GDB_I0 + i] = win->ins[i];
  62
  63         for (i = GDB_F0; i <= GDB_F62; i++)
  64                 gdb_regs[i] = 0;
  65
  66         if (t->new_child)
  67                 pc = (unsigned long) &ret_from_syscall;
  68         else
  69                 pc = (unsigned long) &switch_to_pc;
  70
  71         gdb_regs[GDB_PC] = pc;
  72         gdb_regs[GDB_NPC] = pc + 4;
  73
  74         cwp = __thread_flag_byte_ptr(t)[TI_FLAG_BYTE_CWP];
  75
  76         gdb_regs[GDB_STATE] = (TSTATE_PRIV | TSTATE_IE | cwp);
  77         gdb_regs[GDB_FSR] = 0;
  78         gdb_regs[GDB_FPRS] = 0;
  79         gdb_regs[GDB_Y] = 0;
  80 }
  81
  82 void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
  83 {
  84         struct reg_window *win;
  85         int i;
  86
  87         for (i = 0; i < 15; i++)
  88                 regs->u_regs[UREG_G1 + i] = gdb_regs[GDB_G1 + i];
  89
  90         /* If the TSTATE register is changing, we have to preserve
  91          * the CWP field, otherwise window save/restore explodes.
  92          */
  93         if (regs->tstate != gdb_regs[GDB_STATE]) {
  94                 unsigned long cwp = regs->tstate & TSTATE_CWP;
  95
  96                 regs->tstate = (gdb_regs[GDB_STATE] & ~TSTATE_CWP) | cwp;
  97         }
  98
  99         regs->tpc = gdb_regs[GDB_PC];
 100         regs->tnpc = gdb_regs[GDB_NPC];
 101         regs->y = gdb_regs[GDB_Y];
 102
 103         win = (struct reg_window *) (regs->u_regs[UREG_FP] + STACK_BIAS);
 104         for (i = 0; i < 8; i++)
 105                 win->locals[i] = gdb_regs[GDB_L0 + i];
 106         for (i = 0; i < 8; i++)
 107                 win->ins[i] = gdb_regs[GDB_I0 + i];
 108 }
 109
 110 #ifdef CONFIG_SMP
 111 void smp_kgdb_capture_client(struct pt_regs *regs)
 112 {
 113         unsigned long flags;
 114
 115         __asm__ __volatile__("rdpr      %%pstate, %0\n\t"
 116                              "wrpr      %0, %1, %%pstate"
 117                              : "=r" (flags)
 118                              : "i" (PSTATE_IE));
 119
 120         flushw_all();
 121
 122         if (atomic_read(&kgdb_active) != -1)
 123                 kgdb_nmicallback(raw_smp_processor_id(), regs);
 124
 125         __asm__ __volatile__("wrpr      %0, 0, %%pstate"
 126                              : : "r" (flags));
 127 }
 128 #endif
 129
 130 int kgdb_arch_handle_exception(int e_vector, int signo, int err_code,
 131                                char *remcomInBuffer, char *remcomOutBuffer,
 132                                struct pt_regs *linux_regs)
 133 {
 134         unsigned long addr;
 135         char *ptr;
 136
 137         switch (remcomInBuffer[0]) {
 138         case 'c':
 139                 /* try to read optional parameter, pc unchanged if no parm */
 140                 ptr = &remcomInBuffer[1];
 141                 if (kgdb_hex2long(&ptr, &addr)) {
 142                         linux_regs->tpc = addr;
 143                         linux_regs->tnpc = addr + 4;
 144                 }
 145                 /* fallthru */
 146
 147         case 'D':
 148         case 'k':
 149                 if (linux_regs->tpc == (unsigned long) arch_kgdb_breakpoint) {
 150                         linux_regs->tpc = linux_regs->tnpc;
 151                         linux_regs->tnpc += 4;
 152                 }
 153                 return 0;
 154         }
 155         return -1;
 156 }
 157
 158 asmlinkage void kgdb_trap(unsigned long trap_level, struct pt_regs *regs)
 159 {
 160         unsigned long flags;
 161
 162         if (user_mode(regs)) {
 163                 bad_trap(regs, trap_level);
 164                 return;
 165         }
 166
 167         flushw_all();
 168
 169         local_irq_save(flags);
 170         kgdb_handle_exception(0x172, SIGTRAP, 0, regs);
 171         local_irq_restore(flags);
 172 }
 173
 174 int kgdb_arch_init(void)
 175 {
 176         return 0;
 177 }
 178
 179 void kgdb_arch_exit(void)
 180 {
 181 }
 182
 183 struct kgdb_arch arch_kgdb_ops = {
 184         /* Breakpoint instruction: ta 0x72 */
 185         .gdb_bpt_instr          = { 0x91, 0xd0, 0x20, 0x72 },
 186 };