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