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-rw-r--r--arch/v850/kernel/ptrace.c282
1 files changed, 282 insertions, 0 deletions
diff --git a/arch/v850/kernel/ptrace.c b/arch/v850/kernel/ptrace.c
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+++ b/arch/v850/kernel/ptrace.c
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+/*
+ * arch/v850/kernel/ptrace.c -- `ptrace' system call
+ *
+ * Copyright (C) 2002,03,04 NEC Electronics Corporation
+ * Copyright (C) 2002,03,04 Miles Bader <miles@gnu.org>
+ *
+ * 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 <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/sched.h>
+#include <linux/smp_lock.h>
+#include <linux/ptrace.h>
+
+#include <asm/errno.h>
+#include <asm/ptrace.h>
+#include <asm/processor.h>
+#include <asm/uaccess.h>
+
+/* 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_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;
+}
+
+int sys_ptrace(long request, long pid, long addr, long data)
+{
+ struct task_struct *child;
+ int rval;
+
+ lock_kernel();
+
+ if (request == PTRACE_TRACEME) {
+ /* are we already being traced? */
+ if (current->ptrace & PT_PTRACED) {
+ rval = -EPERM;
+ goto out;
+ }
+ /* set the ptrace bit in the process flags. */
+ current->ptrace |= PT_PTRACED;
+ rval = 0;
+ goto out;
+ }
+ rval = -ESRCH;
+ read_lock(&tasklist_lock);
+ child = find_task_by_pid(pid);
+ if (child)
+ get_task_struct(child);
+ read_unlock(&tasklist_lock);
+ if (!child)
+ goto out;
+
+ rval = -EPERM;
+ if (pid == 1) /* you may not mess with init */
+ goto out_tsk;
+
+ if (request == PTRACE_ATTACH) {
+ rval = ptrace_attach(child);
+ goto out_tsk;
+ }
+ rval = ptrace_check_attach(child, request == PTRACE_KILL);
+ if (rval < 0)
+ goto out_tsk;
+
+ 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 ((unsigned long) data > _NSIG)
+ 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_tsk:
+ put_task_struct(child);
+out:
+ unlock_kernel();
+ 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 */
+}