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