| /* |
| * 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)); |
| } |
| |
| 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) |
| { |
| 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 = generic_ptrace_peekdata(child, addr, data); |
| 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 = generic_ptrace_pokedata(child, addr, data); |
| 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; |
| |
| 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, "ptrace", regs, 0, 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(); |
| set_ti_thread_flag(ti, 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) |
| set_ti_thread_flag(ti, 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); |
| } |
| } |