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-rw-r--r--arch/avr32/kernel/ptrace.c356
1 files changed, 356 insertions, 0 deletions
diff --git a/arch/avr32/kernel/ptrace.c b/arch/avr32/kernel/ptrace.c
new file mode 100644
index 00000000000..4aedcab7cd4
--- /dev/null
+++ b/arch/avr32/kernel/ptrace.c
@@ -0,0 +1,356 @@
+/*
+ * 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/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 <linux/kdebug.h>
+
+static struct pt_regs *get_user_regs(struct task_struct *tsk)
+{
+ return (struct pt_regs *)((unsigned long)task_stack_page(tsk) +
+ THREAD_SIZE - sizeof(struct pt_regs));
+}
+
+void user_enable_single_step(struct task_struct *tsk)
+{
+ pr_debug("user_enable_single_step: pid=%u, PC=0x%08lx, SR=0x%08lx\n",
+ tsk->pid, task_pt_regs(tsk)->pc, task_pt_regs(tsk)->sr);
+
+ /*
+ * We can't schedule in Debug mode, so when TIF_BREAKPOINT is
+ * set, the system call or exception handler will do a
+ * breakpoint to enter monitor mode before returning to
+ * userspace.
+ *
+ * The monitor code will then notice that TIF_SINGLE_STEP is
+ * set and return to userspace with single stepping enabled.
+ * The CPU will then enter monitor mode again after exactly
+ * one instruction has been executed, and the monitor code
+ * will then send a SIGTRAP to the process.
+ */
+ set_tsk_thread_flag(tsk, TIF_BREAKPOINT);
+ set_tsk_thread_flag(tsk, TIF_SINGLE_STEP);
+}
+
+void user_disable_single_step(struct task_struct *child)
+{
+ /* XXX(hch): a no-op here seems wrong.. */
+}
+
+/*
+ * 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);
+ clear_tsk_thread_flag(child, TIF_BREAKPOINT);
+ ocd_disable(child);
+}
+
+/*
+ * 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;
+
+ 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])];
+
+ pr_debug("ptrace_read_user(%s[%u], %#lx, %p) -> %#lx\n",
+ tsk->comm, tsk->pid, offset, data, value);
+
+ 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;
+
+ pr_debug("ptrace_write_user(%s[%u], %#lx, %#lx)\n",
+ tsk->comm, tsk->pid, offset, value);
+
+ if (offset & 3 || offset >= sizeof(struct user)) {
+ pr_debug(" 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,
+ unsigned long addr, unsigned long data)
+{
+ int ret;
+ void __user *datap = (void __user *) data;
+
+ switch (request) {
+ /* Read the word at location addr in the child process */
+ case PTRACE_PEEKTEXT:
+ case PTRACE_PEEKDATA:
+ ret = generic_ptrace_peekdata(child, addr, data);
+ break;
+
+ case PTRACE_PEEKUSR:
+ ret = ptrace_read_user(child, addr, datap);
+ break;
+
+ /* Write the word in data at location addr */
+ case PTRACE_POKETEXT:
+ case PTRACE_POKEDATA:
+ ret = generic_ptrace_pokedata(child, addr, data);
+ break;
+
+ case PTRACE_POKEUSR:
+ ret = ptrace_write_user(child, addr, data);
+ break;
+
+ case PTRACE_GETREGS:
+ ret = ptrace_getregs(child, datap);
+ break;
+
+ case PTRACE_SETREGS:
+ ret = ptrace_setregs(child, datap);
+ break;
+
+ default:
+ ret = ptrace_request(child, request, addr, data);
+ break;
+ }
+
+ return ret;
+}
+
+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) {
+ 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;
+ }
+}
+
+/*
+ * debug_trampoline() is an assembly stub which will store all user
+ * registers on the stack and execute a breakpoint instruction.
+ *
+ * If we single-step into an exception handler which runs with
+ * interrupts disabled the whole time so it doesn't have to check for
+ * pending work, its return address will be modified so that it ends
+ * up returning to debug_trampoline.
+ *
+ * If the exception handler decides to store the user context and
+ * enable interrupts after all, it will restore the original return
+ * address and status register value. Before it returns, it will
+ * notice that TIF_BREAKPOINT is set and execute a breakpoint
+ * instruction.
+ */
+extern void debug_trampoline(void);
+
+asmlinkage struct pt_regs *do_debug(struct pt_regs *regs)
+{
+ struct thread_info *ti;
+ unsigned long trampoline_addr;
+ u32 status;
+ u32 ctrl;
+ int code;
+
+ status = ocd_read(DS);
+ ti = current_thread_info();
+ code = TRAP_BRKPT;
+
+ pr_debug("do_debug: status=0x%08x PC=0x%08lx SR=0x%08lx tif=0x%08lx\n",
+ status, regs->pc, regs->sr, ti->flags);
+
+ if (!user_mode(regs)) {
+ unsigned long die_val = DIE_BREAKPOINT;
+
+ if (status & (1 << OCD_DS_SSS_BIT))
+ die_val = DIE_SSTEP;
+
+ if (notify_die(die_val, "ptrace", regs, 0, 0, SIGTRAP)
+ == NOTIFY_STOP)
+ return regs;
+
+ if ((status & (1 << OCD_DS_SWB_BIT))
+ && test_and_clear_ti_thread_flag(
+ ti, TIF_BREAKPOINT)) {
+ /*
+ * Explicit breakpoint from trampoline or
+ * exception/syscall/interrupt handler.
+ *
+ * The real saved regs are on the stack right
+ * after the ones we saved on entry.
+ */
+ regs++;
+ pr_debug(" -> TIF_BREAKPOINT done, adjusted regs:"
+ "PC=0x%08lx SR=0x%08lx\n",
+ regs->pc, regs->sr);
+ BUG_ON(!user_mode(regs));
+
+ if (test_thread_flag(TIF_SINGLE_STEP)) {
+ pr_debug("Going to do single step...\n");
+ return regs;
+ }
+
+ /*
+ * No TIF_SINGLE_STEP means we're done
+ * stepping over a syscall. Do the trap now.
+ */
+ code = TRAP_TRACE;
+ } else if ((status & (1 << OCD_DS_SSS_BIT))
+ && test_ti_thread_flag(ti, TIF_SINGLE_STEP)) {
+
+ pr_debug("Stepped into something, "
+ "setting TIF_BREAKPOINT...\n");
+ set_ti_thread_flag(ti, TIF_BREAKPOINT);
+
+ /*
+ * We stepped into an exception, interrupt or
+ * syscall handler. Some exception handlers
+ * don't check for pending work, so we need to
+ * set up a trampoline just in case.
+ *
+ * The exception entry code will undo the
+ * trampoline stuff if it does a full context
+ * save (which also means that it'll check for
+ * pending work later.)
+ */
+ if ((regs->sr & MODE_MASK) == MODE_EXCEPTION) {
+ trampoline_addr
+ = (unsigned long)&debug_trampoline;
+
+ pr_debug("Setting up trampoline...\n");
+ ti->rar_saved = sysreg_read(RAR_EX);
+ ti->rsr_saved = sysreg_read(RSR_EX);
+ sysreg_write(RAR_EX, trampoline_addr);
+ sysreg_write(RSR_EX, (MODE_EXCEPTION
+ | SR_EM | SR_GM));
+ BUG_ON(ti->rsr_saved & MODE_MASK);
+ }
+
+ /*
+ * If we stepped into a system call, we
+ * shouldn't do a single step after we return
+ * since the return address is right after the
+ * "scall" instruction we were told to step
+ * over.
+ */
+ if ((regs->sr & MODE_MASK) == MODE_SUPERVISOR) {
+ pr_debug("Supervisor; no single step\n");
+ clear_ti_thread_flag(ti, TIF_SINGLE_STEP);
+ }
+
+ ctrl = ocd_read(DC);
+ ctrl &= ~(1 << OCD_DC_SS_BIT);
+ ocd_write(DC, ctrl);
+
+ return regs;
+ } else {
+ printk(KERN_ERR "Unexpected OCD_DS value: 0x%08x\n",
+ status);
+ printk(KERN_ERR "Thread flags: 0x%08lx\n", ti->flags);
+ die("Unhandled debug trap in kernel mode",
+ regs, SIGTRAP);
+ }
+ } else if (status & (1 << OCD_DS_SSS_BIT)) {
+ /* Single step in user mode */
+ code = TRAP_TRACE;
+
+ ctrl = ocd_read(DC);
+ ctrl &= ~(1 << OCD_DC_SS_BIT);
+ ocd_write(DC, ctrl);
+ }
+
+ pr_debug("Sending SIGTRAP: code=%d PC=0x%08lx SR=0x%08lx\n",
+ code, regs->pc, regs->sr);
+
+ clear_thread_flag(TIF_SINGLE_STEP);
+ _exception(SIGTRAP, regs, code, instruction_pointer(regs));
+
+ return regs;
+}