1 files changed, 282 insertions, 0 deletions

diff --git a/arch/v850/kernel/ptrace.c b/arch/v850/kernel/ptrace.c
new file mode 100644
index 000000000000..8fa780757dcd
--- /dev/null
+++ b/arch/v850/kernel/ptrace.c
@@ -0,0 +1,282 @@
+/*
+ * 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 */
+}