--- /dev/null
+/*
+ * Copyright (C) 2004-2006 Atmel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#undef DEBUG
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/smp_lock.h>
+#include <linux/ptrace.h>
+#include <linux/errno.h>
+#include <linux/user.h>
+#include <linux/security.h>
+#include <linux/unistd.h>
+#include <linux/notifier.h>
+
+#include <asm/traps.h>
+#include <asm/uaccess.h>
+#include <asm/ocd.h>
+#include <asm/mmu_context.h>
+#include <asm/kdebug.h>
+
+static struct pt_regs *get_user_regs(struct task_struct *tsk)
+{
+ return (struct pt_regs *)((unsigned long) tsk->thread_info +
+ THREAD_SIZE - sizeof(struct pt_regs));
+}
+
+static void ptrace_single_step(struct task_struct *tsk)
+{
+ pr_debug("ptrace_single_step: pid=%u, SR=0x%08lx\n",
+ tsk->pid, tsk->thread.cpu_context.sr);
+ if (!(tsk->thread.cpu_context.sr & SR_D)) {
+ /*
+ * Set a breakpoint at the current pc to force the
+ * process into debug mode. The syscall/exception
+ * exit code will set a breakpoint at the return
+ * address when this flag is set.
+ */
+ pr_debug("ptrace_single_step: Setting TIF_BREAKPOINT\n");
+ set_tsk_thread_flag(tsk, TIF_BREAKPOINT);
+ }
+
+ /* The monitor code will do the actual step for us */
+ set_tsk_thread_flag(tsk, TIF_SINGLE_STEP);
+}
+
+/*
+ * Called by kernel/ptrace.c when detaching
+ *
+ * Make sure any single step bits, etc. are not set
+ */
+void ptrace_disable(struct task_struct *child)
+{
+ clear_tsk_thread_flag(child, TIF_SINGLE_STEP);
+}
+
+/*
+ * Handle hitting a breakpoint
+ */
+static void ptrace_break(struct task_struct *tsk, struct pt_regs *regs)
+{
+ siginfo_t info;
+
+ info.si_signo = SIGTRAP;
+ info.si_errno = 0;
+ info.si_code = TRAP_BRKPT;
+ info.si_addr = (void __user *)instruction_pointer(regs);
+
+ pr_debug("ptrace_break: Sending SIGTRAP to PID %u (pc = 0x%p)\n",
+ tsk->pid, info.si_addr);
+ force_sig_info(SIGTRAP, &info, tsk);
+}
+
+/*
+ * Read the word at offset "offset" into the task's "struct user". We
+ * actually access the pt_regs struct stored on the kernel stack.
+ */
+static int ptrace_read_user(struct task_struct *tsk, unsigned long offset,
+ unsigned long __user *data)
+{
+ unsigned long *regs;
+ unsigned long value;
+
+ pr_debug("ptrace_read_user(%p, %#lx, %p)\n",
+ tsk, offset, data);
+
+ if (offset & 3 || offset >= sizeof(struct user)) {
+ printk("ptrace_read_user: invalid offset 0x%08lx\n", offset);
+ return -EIO;
+ }
+
+ regs = (unsigned long *)get_user_regs(tsk);
+
+ value = 0;
+ if (offset < sizeof(struct pt_regs))
+ value = regs[offset / sizeof(regs[0])];
+
+ return put_user(value, data);
+}
+
+/*
+ * Write the word "value" to offset "offset" into the task's "struct
+ * user". We actually access the pt_regs struct stored on the kernel
+ * stack.
+ */
+static int ptrace_write_user(struct task_struct *tsk, unsigned long offset,
+ unsigned long value)
+{
+ unsigned long *regs;
+
+ if (offset & 3 || offset >= sizeof(struct user)) {
+ printk("ptrace_write_user: invalid offset 0x%08lx\n", offset);
+ return -EIO;
+ }
+
+ if (offset >= sizeof(struct pt_regs))
+ return 0;
+
+ regs = (unsigned long *)get_user_regs(tsk);
+ regs[offset / sizeof(regs[0])] = value;
+
+ return 0;
+}
+
+static int ptrace_getregs(struct task_struct *tsk, void __user *uregs)
+{
+ struct pt_regs *regs = get_user_regs(tsk);
+
+ return copy_to_user(uregs, regs, sizeof(*regs)) ? -EFAULT : 0;
+}
+
+static int ptrace_setregs(struct task_struct *tsk, const void __user *uregs)
+{
+ struct pt_regs newregs;
+ int ret;
+
+ ret = -EFAULT;
+ if (copy_from_user(&newregs, uregs, sizeof(newregs)) == 0) {
+ struct pt_regs *regs = get_user_regs(tsk);
+
+ ret = -EINVAL;
+ if (valid_user_regs(&newregs)) {
+ *regs = newregs;
+ ret = 0;
+ }
+ }
+
+ return ret;
+}
+
+long arch_ptrace(struct task_struct *child, long request, long addr, long data)
+{
+ unsigned long tmp;
+ int ret;
+
+ pr_debug("arch_ptrace(%ld, %d, %#lx, %#lx)\n",
+ request, child->pid, addr, data);
+
+ pr_debug("ptrace: Enabling monitor mode...\n");
+ __mtdr(DBGREG_DC, __mfdr(DBGREG_DC) | DC_MM | DC_DBE);
+
+ switch (request) {
+ /* Read the word at location addr in the child process */
+ case PTRACE_PEEKTEXT:
+ case PTRACE_PEEKDATA:
+ ret = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
+ if (ret == sizeof(tmp))
+ ret = put_user(tmp, (unsigned long __user *)data);
+ else
+ ret = -EIO;
+ break;
+
+ case PTRACE_PEEKUSR:
+ ret = ptrace_read_user(child, addr,
+ (unsigned long __user *)data);
+ break;
+
+ /* Write the word in data at location addr */
+ case PTRACE_POKETEXT:
+ case PTRACE_POKEDATA:
+ ret = access_process_vm(child, addr, &data, sizeof(data), 1);
+ if (ret == sizeof(data))
+ ret = 0;
+ else
+ ret = -EIO;
+ break;
+
+ case PTRACE_POKEUSR:
+ ret = ptrace_write_user(child, addr, data);
+ break;
+
+ /* continue and stop at next (return from) syscall */
+ case PTRACE_SYSCALL:
+ /* restart after signal */
+ case PTRACE_CONT:
+ ret = -EIO;
+ if (!valid_signal(data))
+ 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;
+ /* XXX: Are we sure no breakpoints are active here? */
+ wake_up_process(child);
+ ret = 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:
+ ret = 0;
+ if (child->exit_state == EXIT_ZOMBIE)
+ break;
+ child->exit_code = SIGKILL;
+ wake_up_process(child);
+ break;
+
+ /*
+ * execute single instruction.
+ */
+ case PTRACE_SINGLESTEP:
+ ret = -EIO;
+ if (!valid_signal(data))
+ break;
+ clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+ ptrace_single_step(child);
+ child->exit_code = data;
+ wake_up_process(child);
+ ret = 0;
+ break;
+
+ /* Detach a process that was attached */
+ case PTRACE_DETACH:
+ ret = ptrace_detach(child, data);
+ break;
+
+ case PTRACE_GETREGS:
+ ret = ptrace_getregs(child, (void __user *)data);
+ break;
+
+ case PTRACE_SETREGS:
+ ret = ptrace_setregs(child, (const void __user *)data);
+ break;
+
+ default:
+ ret = ptrace_request(child, request, addr, data);
+ break;
+ }
+
+ pr_debug("sys_ptrace returning %d (DC = 0x%08lx)\n", ret, __mfdr(DBGREG_DC));
+ return ret;
+}
+
+asmlinkage void syscall_trace(void)
+{
+ pr_debug("syscall_trace called\n");
+ if (!test_thread_flag(TIF_SYSCALL_TRACE))
+ return;
+ if (!(current->ptrace & PT_PTRACED))
+ return;
+
+ pr_debug("syscall_trace: notifying parent\n");
+ /* 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) {
+ pr_debug("syscall_trace: sending signal %d to PID %u\n",
+ current->exit_code, current->pid);
+ send_sig(current->exit_code, current, 1);
+ current->exit_code = 0;
+ }
+}
+
+asmlinkage void do_debug_priv(struct pt_regs *regs)
+{
+ unsigned long dc, ds;
+ unsigned long die_val;
+
+ ds = __mfdr(DBGREG_DS);
+
+ pr_debug("do_debug_priv: pc = %08lx, ds = %08lx\n", regs->pc, ds);
+
+ if (ds & DS_SSS)
+ die_val = DIE_SSTEP;
+ else
+ die_val = DIE_BREAKPOINT;
+
+ if (notify_die(die_val, regs, 0, SIGTRAP) == NOTIFY_STOP)
+ return;
+
+ if (likely(ds & DS_SSS)) {
+ extern void itlb_miss(void);
+ extern void tlb_miss_common(void);
+ struct thread_info *ti;
+
+ dc = __mfdr(DBGREG_DC);
+ dc &= ~DC_SS;
+ __mtdr(DBGREG_DC, dc);
+
+ ti = current_thread_info();
+ ti->flags |= _TIF_BREAKPOINT;
+
+ /* The TLB miss handlers don't check thread flags */
+ if ((regs->pc >= (unsigned long)&itlb_miss)
+ && (regs->pc <= (unsigned long)&tlb_miss_common)) {
+ __mtdr(DBGREG_BWA2A, sysreg_read(RAR_EX));
+ __mtdr(DBGREG_BWC2A, 0x40000001 | (get_asid() << 1));
+ }
+
+ /*
+ * If we're running in supervisor mode, the breakpoint
+ * will take us where we want directly, no need to
+ * single step.
+ */
+ if ((regs->sr & MODE_MASK) != MODE_SUPERVISOR)
+ ti->flags |= TIF_SINGLE_STEP;
+ } else {
+ panic("Unable to handle debug trap at pc = %08lx\n",
+ regs->pc);
+ }
+}
+
+/*
+ * Handle breakpoints, single steps and other debuggy things. To keep
+ * things simple initially, we run with interrupts and exceptions
+ * disabled all the time.
+ */
+asmlinkage void do_debug(struct pt_regs *regs)
+{
+ unsigned long dc, ds;
+
+ ds = __mfdr(DBGREG_DS);
+ pr_debug("do_debug: pc = %08lx, ds = %08lx\n", regs->pc, ds);
+
+ if (test_thread_flag(TIF_BREAKPOINT)) {
+ pr_debug("TIF_BREAKPOINT set\n");
+ /* We're taking care of it */
+ clear_thread_flag(TIF_BREAKPOINT);
+ __mtdr(DBGREG_BWC2A, 0);
+ }
+
+ if (test_thread_flag(TIF_SINGLE_STEP)) {
+ pr_debug("TIF_SINGLE_STEP set, ds = 0x%08lx\n", ds);
+ if (ds & DS_SSS) {
+ dc = __mfdr(DBGREG_DC);
+ dc &= ~DC_SS;
+ __mtdr(DBGREG_DC, dc);
+
+ clear_thread_flag(TIF_SINGLE_STEP);
+ ptrace_break(current, regs);
+ }
+ } else {
+ /* regular breakpoint */
+ ptrace_break(current, regs);
+ }
+}
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