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kgdb.c

/* kgdb.c: KGDB support for 32-bit sparc.
 *
 * Copyright (C) 2008 David S. Miller <davem@davemloft.net>
 */

#include <linux/kgdb.h>
#include <linux/kdebug.h>

#include <asm/kdebug.h>
#include <asm/ptrace.h>
#include <asm/irq.h>

extern unsigned long trapbase;

void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
{
      struct reg_window *win;
      int i;

      gdb_regs[GDB_G0] = 0;
      for (i = 0; i < 15; i++)
            gdb_regs[GDB_G1 + i] = regs->u_regs[UREG_G1 + i];

      win = (struct reg_window *) regs->u_regs[UREG_FP];
      for (i = 0; i < 8; i++)
            gdb_regs[GDB_L0 + i] = win->locals[i];
      for (i = 0; i < 8; i++)
            gdb_regs[GDB_I0 + i] = win->ins[i];

      for (i = GDB_F0; i <= GDB_F31; i++)
            gdb_regs[i] = 0;

      gdb_regs[GDB_Y] = regs->y;
      gdb_regs[GDB_PSR] = regs->psr;
      gdb_regs[GDB_WIM] = 0;
      gdb_regs[GDB_TBR] = (unsigned long) &trapbase;
      gdb_regs[GDB_PC] = regs->pc;
      gdb_regs[GDB_NPC] = regs->npc;
      gdb_regs[GDB_FSR] = 0;
      gdb_regs[GDB_CSR] = 0;
}

void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
{
      struct thread_info *t = task_thread_info(p);
      struct reg_window *win;
      int i;

      for (i = GDB_G0; i < GDB_G6; i++)
            gdb_regs[i] = 0;
      gdb_regs[GDB_G6] = (unsigned long) t;
      gdb_regs[GDB_G7] = 0;
      for (i = GDB_O0; i < GDB_SP; i++)
            gdb_regs[i] = 0;
      gdb_regs[GDB_SP] = t->ksp;
      gdb_regs[GDB_O7] = 0;

      win = (struct reg_window *) t->ksp;
      for (i = 0; i < 8; i++)
            gdb_regs[GDB_L0 + i] = win->locals[i];
      for (i = 0; i < 8; i++)
            gdb_regs[GDB_I0 + i] = win->ins[i];

      for (i = GDB_F0; i <= GDB_F31; i++)
            gdb_regs[i] = 0;

      gdb_regs[GDB_Y] = 0;

      gdb_regs[GDB_PSR] = t->kpsr;
      gdb_regs[GDB_WIM] = t->kwim;
      gdb_regs[GDB_TBR] = (unsigned long) &trapbase;
      gdb_regs[GDB_PC] = t->kpc;
      gdb_regs[GDB_NPC] = t->kpc + 4;
      gdb_regs[GDB_FSR] = 0;
      gdb_regs[GDB_CSR] = 0;
}

void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
{
      struct reg_window *win;
      int i;

      for (i = 0; i < 15; i++)
            regs->u_regs[UREG_G1 + i] = gdb_regs[GDB_G1 + i];

      /* If the PSR register is changing, we have to preserve
       * the CWP field, otherwise window save/restore explodes.
       */
      if (regs->psr != gdb_regs[GDB_PSR]) {
            unsigned long cwp = regs->psr & PSR_CWP;

            regs->psr = (gdb_regs[GDB_PSR] & ~PSR_CWP) | cwp;
      }

      regs->pc = gdb_regs[GDB_PC];
      regs->npc = gdb_regs[GDB_NPC];
      regs->y = gdb_regs[GDB_Y];

      win = (struct reg_window *) regs->u_regs[UREG_FP];
      for (i = 0; i < 8; i++)
            win->locals[i] = gdb_regs[GDB_L0 + i];
      for (i = 0; i < 8; i++)
            win->ins[i] = gdb_regs[GDB_I0 + i];
}

int kgdb_arch_handle_exception(int e_vector, int signo, int err_code,
                         char *remcomInBuffer, char *remcomOutBuffer,
                         struct pt_regs *linux_regs)
{
      unsigned long addr;
      char *ptr;

      switch (remcomInBuffer[0]) {
      case 'c':
            /* try to read optional parameter, pc unchanged if no parm */
            ptr = &remcomInBuffer[1];
            if (kgdb_hex2long(&ptr, &addr)) {
                  linux_regs->pc = addr;
                  linux_regs->npc = addr + 4;
            }
            /* fallthru */

      case 'D':
      case 'k':
            if (linux_regs->pc == (unsigned long) arch_kgdb_breakpoint) {
                  linux_regs->pc = linux_regs->npc;
                  linux_regs->npc += 4;
            }
            return 0;
      }
      return -1;
}

extern void do_hw_interrupt(struct pt_regs *regs, unsigned long type);

asmlinkage void kgdb_trap(struct pt_regs *regs)
{
      unsigned long flags;

      if (user_mode(regs)) {
            do_hw_interrupt(regs, 0xfd);
            return;
      }

      flushw_all();

      local_irq_save(flags);
      kgdb_handle_exception(0x172, SIGTRAP, 0, regs);
      local_irq_restore(flags);
}

int kgdb_arch_init(void)
{
      return 0;
}

void kgdb_arch_exit(void)
{
}

struct kgdb_arch arch_kgdb_ops = {
      /* Breakpoint instruction: ta 0x7d */
      .gdb_bpt_instr          = { 0x91, 0xd0, 0x20, 0x7d },
};

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