2 * arch/v850/kernel/ptrace.c -- `ptrace' system call
4 * Copyright (C) 2002,03,04 NEC Electronics Corporation
5 * Copyright (C) 2002,03,04 Miles Bader <miles@gnu.org>
7 * Derived from arch/mips/kernel/ptrace.c:
9 * Copyright (C) 1992 Ross Biro
10 * Copyright (C) Linus Torvalds
11 * Copyright (C) 1994, 95, 96, 97, 98, 2000 Ralf Baechle
12 * Copyright (C) 1996 David S. Miller
13 * Kevin D. Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com
14 * Copyright (C) 1999 MIPS Technologies, Inc.
16 * This file is subject to the terms and conditions of the GNU General
17 * Public License. See the file COPYING in the main directory of this
18 * archive for more details.
21 #include <linux/kernel.h>
23 #include <linux/sched.h>
24 #include <linux/smp_lock.h>
25 #include <linux/ptrace.h>
27 #include <asm/errno.h>
28 #include <asm/ptrace.h>
29 #include <asm/processor.h>
30 #include <asm/uaccess.h>
32 /* Returns the address where the register at REG_OFFS in P is stashed away. */
33 static v850_reg_t *reg_save_addr (unsigned reg_offs, struct task_struct *t)
39 (1) A register normally saved before calling the scheduler, is
40 available in the kernel entry pt_regs structure at the top
41 of the kernel stack. The kernel trap/irq exit path takes
42 care to save/restore almost all registers for ptrace'd
45 (2) A call-clobbered register, where the process P entered the
46 kernel via [syscall] trap, is not stored anywhere; that's
47 OK, because such registers are not expected to be preserved
48 when the trap returns anyway (so we don't actually bother to
51 (3) A few registers not used at all by the kernel, and so
52 normally never saved except by context-switches, are in the
53 context switch state. */
55 if (reg_offs == PT_CTPC || reg_offs == PT_CTPSW || reg_offs == PT_CTBP)
56 /* Register saved during context switch. */
57 regs = thread_saved_regs (t);
59 /* Register saved during kernel entry (or not available). */
62 return (v850_reg_t *)((char *)regs + reg_offs);
65 /* Set the bits SET and clear the bits CLEAR in the v850e DIR
66 (`debug information register'). Returns the new value of DIR. */
67 static inline v850_reg_t set_dir (v850_reg_t set, v850_reg_t clear)
69 register v850_reg_t rval asm ("r10");
70 register v850_reg_t arg0 asm ("r6") = set;
71 register v850_reg_t arg1 asm ("r7") = clear;
73 /* The dbtrap handler has exactly this functionality when called
74 from kernel mode. 0xf840 is a `dbtrap' insn. */
75 asm (".short 0xf840" : "=r" (rval) : "r" (arg0), "r" (arg1));
80 /* Makes sure hardware single-stepping is (globally) enabled.
81 Returns true if successful. */
82 static inline int enable_single_stepping (void)
84 static int enabled = 0; /* Remember whether we already did it. */
86 /* Turn on the SE (`single-step enable') bit, 0x100, in the
87 DIR (`debug information register'). This may fail if a
88 processor doesn't support it or something. We also try
89 to clear bit 0x40 (`INI'), which is necessary to use the
90 debug stuff on the v850e2; on the v850e, clearing 0x40
91 shouldn't cause any problem. */
92 v850_reg_t dir = set_dir (0x100, 0x40);
93 /* Make sure it really got set. */
100 /* Try to set CHILD's single-step flag to VAL. Returns true if successful. */
101 static int set_single_step (struct task_struct *t, int val)
103 v850_reg_t *psw_addr = reg_save_addr(PT_PSW, t);
105 /* Make sure single-stepping is enabled. */
106 if (! enable_single_stepping ())
108 /* Set T's single-step flag. */
115 int sys_ptrace(long request, long pid, long addr, long data)
117 struct task_struct *child;
122 if (request == PTRACE_TRACEME) {
123 /* are we already being traced? */
124 if (current->ptrace & PT_PTRACED) {
128 /* set the ptrace bit in the process flags. */
129 current->ptrace |= PT_PTRACED;
134 read_lock(&tasklist_lock);
135 child = find_task_by_pid(pid);
137 get_task_struct(child);
138 read_unlock(&tasklist_lock);
143 if (pid == 1) /* you may not mess with init */
146 if (request == PTRACE_ATTACH) {
147 rval = ptrace_attach(child);
150 rval = ptrace_check_attach(child, request == PTRACE_KILL);
155 unsigned long val, copied;
157 case PTRACE_PEEKTEXT: /* read word at location addr. */
158 case PTRACE_PEEKDATA:
159 copied = access_process_vm(child, addr, &val, sizeof(val), 0);
161 if (copied != sizeof(val))
163 rval = put_user(val, (unsigned long *)data);
166 case PTRACE_POKETEXT: /* write the word at location addr. */
167 case PTRACE_POKEDATA:
169 if (access_process_vm(child, addr, &data, sizeof(data), 1)
175 /* Read/write the word at location ADDR in the registers. */
179 if (addr >= PT_SIZE && request == PTRACE_PEEKUSR) {
180 /* Special requests that don't actually correspond
181 to offsets in struct pt_regs. */
182 if (addr == PT_TEXT_ADDR)
183 val = child->mm->start_code;
184 else if (addr == PT_DATA_ADDR)
185 val = child->mm->start_data;
186 else if (addr == PT_TEXT_LEN)
187 val = child->mm->end_code
188 - child->mm->start_code;
191 } else if (addr >= 0 && addr < PT_SIZE && (addr & 0x3) == 0) {
192 v850_reg_t *reg_addr = reg_save_addr(addr, child);
193 if (request == PTRACE_PEEKUSR)
200 if (rval == 0 && request == PTRACE_PEEKUSR)
201 rval = put_user (val, (unsigned long *)data);
204 /* Continue and stop at next (return from) syscall */
206 /* Restart after a signal. */
208 /* Execute a single instruction. */
209 case PTRACE_SINGLESTEP:
211 if ((unsigned long) data > _NSIG)
214 /* Turn CHILD's single-step flag on or off. */
215 if (! set_single_step (child, request == PTRACE_SINGLESTEP))
218 if (request == PTRACE_SYSCALL)
219 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
221 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
223 child->exit_code = data;
224 wake_up_process(child);
229 * make the child exit. Best I can do is send it a sigkill.
230 * perhaps it should be put in the status that it wants to
235 if (child->exit_state == EXIT_ZOMBIE) /* already dead */
237 child->exit_code = SIGKILL;
238 wake_up_process(child);
241 case PTRACE_DETACH: /* detach a process that was attached. */
242 set_single_step (child, 0); /* Clear single-step flag */
243 rval = ptrace_detach(child, data);
252 put_task_struct(child);
258 asmlinkage void syscall_trace(void)
260 if (!test_thread_flag(TIF_SYSCALL_TRACE))
262 if (!(current->ptrace & PT_PTRACED))
264 /* The 0x80 provides a way for the tracing parent to distinguish
265 between a syscall stop and SIGTRAP delivery */
266 ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
269 * this isn't the same as continuing with a signal, but it will do
270 * for normal use. strace only continues with a signal if the
271 * stopping signal is not SIGTRAP. -brl
273 if (current->exit_code) {
274 send_sig(current->exit_code, current, 1);
275 current->exit_code = 0;
279 void ptrace_disable (struct task_struct *child)