/* * arch/v850/kernel/ptrace.c -- `ptrace' system call * * Copyright (C) 2002,03,04 NEC Electronics Corporation * Copyright (C) 2002,03,04 Miles Bader * * Derived from arch/mips/kernel/ptrace.c: * * Copyright (C) 1992 Ross Biro * Copyright (C) Linus Torvalds * Copyright (C) 1994, 95, 96, 97, 98, 2000 Ralf Baechle * Copyright (C) 1996 David S. Miller * Kevin D. Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com * Copyright (C) 1999 MIPS Technologies, Inc. * * This file is subject to the terms and conditions of the GNU General * Public License. See the file COPYING in the main directory of this * archive for more details. */ #include #include #include #include #include #include #include #include #include /* Returns the address where the register at REG_OFFS in P is stashed away. */ static v850_reg_t *reg_save_addr (unsigned reg_offs, struct task_struct *t) { struct pt_regs *regs; /* Three basic cases: (1) A register normally saved before calling the scheduler, is available in the kernel entry pt_regs structure at the top of the kernel stack. The kernel trap/irq exit path takes care to save/restore almost all registers for ptrace'd processes. (2) A call-clobbered register, where the process P entered the kernel via [syscall] trap, is not stored anywhere; that's OK, because such registers are not expected to be preserved when the trap returns anyway (so we don't actually bother to test for this case). (3) A few registers not used at all by the kernel, and so normally never saved except by context-switches, are in the context switch state. */ if (reg_offs == PT_CTPC || reg_offs == PT_CTPSW || reg_offs == PT_CTBP) /* Register saved during context switch. */ regs = thread_saved_regs (t); else /* Register saved during kernel entry (or not available). */ regs = task_pt_regs (t); return (v850_reg_t *)((char *)regs + reg_offs); } /* Set the bits SET and clear the bits CLEAR in the v850e DIR (`debug information register'). Returns the new value of DIR. */ static inline v850_reg_t set_dir (v850_reg_t set, v850_reg_t clear) { register v850_reg_t rval asm ("r10"); register v850_reg_t arg0 asm ("r6") = set; register v850_reg_t arg1 asm ("r7") = clear; /* The dbtrap handler has exactly this functionality when called from kernel mode. 0xf840 is a `dbtrap' insn. */ asm (".short 0xf840" : "=r" (rval) : "r" (arg0), "r" (arg1)); return rval; } /* Makes sure hardware single-stepping is (globally) enabled. Returns true if successful. */ static inline int enable_single_stepping (void) { static int enabled = 0; /* Remember whether we already did it. */ if (! enabled) { /* Turn on the SE (`single-step enable') bit, 0x100, in the DIR (`debug information register'). This may fail if a processor doesn't support it or something. We also try to clear bit 0x40 (`INI'), which is necessary to use the debug stuff on the v850e2; on the v850e, clearing 0x40 shouldn't cause any problem. */ v850_reg_t dir = set_dir (0x100, 0x40); /* Make sure it really got set. */ if (dir & 0x100) enabled = 1; } return enabled; } /* Try to set CHILD's single-step flag to VAL. Returns true if successful. */ static int set_single_step (struct task_struct *t, int val) { v850_reg_t *psw_addr = reg_save_addr(PT_PSW, t); if (val) { /* Make sure single-stepping is enabled. */ if (! enable_single_stepping ()) return 0; /* Set T's single-step flag. */ *psw_addr |= 0x800; } else *psw_addr &= ~0x800; return 1; } long arch_ptrace(struct task_struct *child, long request, long addr, long data) { int rval; switch (request) { unsigned long val, copied; case PTRACE_PEEKTEXT: /* read word at location addr. */ case PTRACE_PEEKDATA: copied = access_process_vm(child, addr, &val, sizeof(val), 0); rval = -EIO; if (copied != sizeof(val)) break; rval = put_user(val, (unsigned long *)data); goto out; case PTRACE_POKETEXT: /* write the word at location addr. */ case PTRACE_POKEDATA: rval = 0; if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data)) break; rval = -EIO; goto out; /* Read/write the word at location ADDR in the registers. */ case PTRACE_PEEKUSR: case PTRACE_POKEUSR: rval = 0; if (addr >= PT_SIZE && request == PTRACE_PEEKUSR) { /* Special requests that don't actually correspond to offsets in struct pt_regs. */ if (addr == PT_TEXT_ADDR) val = child->mm->start_code; else if (addr == PT_DATA_ADDR) val = child->mm->start_data; else if (addr == PT_TEXT_LEN) val = child->mm->end_code - child->mm->start_code; else rval = -EIO; } else if (addr >= 0 && addr < PT_SIZE && (addr & 0x3) == 0) { v850_reg_t *reg_addr = reg_save_addr(addr, child); if (request == PTRACE_PEEKUSR) val = *reg_addr; else *reg_addr = data; } else rval = -EIO; if (rval == 0 && request == PTRACE_PEEKUSR) rval = put_user (val, (unsigned long *)data); goto out; /* Continue and stop at next (return from) syscall */ case PTRACE_SYSCALL: /* Restart after a signal. */ case PTRACE_CONT: /* Execute a single instruction. */ case PTRACE_SINGLESTEP: rval = -EIO; if (!valid_signal(data)) break; /* Turn CHILD's single-step flag on or off. */ if (! set_single_step (child, request == PTRACE_SINGLESTEP)) break; if (request == PTRACE_SYSCALL) set_tsk_thread_flag(child, TIF_SYSCALL_TRACE); else clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); child->exit_code = data; wake_up_process(child); rval = 0; break; /* * make the child exit. Best I can do is send it a sigkill. * perhaps it should be put in the status that it wants to * exit. */ case PTRACE_KILL: rval = 0; if (child->exit_state == EXIT_ZOMBIE) /* already dead */ break; child->exit_code = SIGKILL; wake_up_process(child); break; case PTRACE_DETACH: /* detach a process that was attached. */ set_single_step (child, 0); /* Clear single-step flag */ rval = ptrace_detach(child, data); break; default: rval = -EIO; goto out; } out: return rval; } asmlinkage void syscall_trace(void) { if (!test_thread_flag(TIF_SYSCALL_TRACE)) return; if (!(current->ptrace & PT_PTRACED)) return; /* The 0x80 provides a way for the tracing parent to distinguish between a syscall stop and SIGTRAP delivery */ ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) ? 0x80 : 0)); /* * this isn't the same as continuing with a signal, but it will do * for normal use. strace only continues with a signal if the * stopping signal is not SIGTRAP. -brl */ if (current->exit_code) { send_sig(current->exit_code, current, 1); current->exit_code = 0; } } void ptrace_disable (struct task_struct *child) { /* nothing to do */ }