diff options
Diffstat (limited to 'arch/ia64/kernel/ptrace.c')
-rw-r--r-- | arch/ia64/kernel/ptrace.c | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/arch/ia64/kernel/ptrace.c b/arch/ia64/kernel/ptrace.c index 2e96f17..2de5a52 100644 --- a/arch/ia64/kernel/ptrace.c +++ b/arch/ia64/kernel/ptrace.c @@ -547,6 +547,72 @@ ia64_sync_user_rbs (struct task_struct *child, struct switch_stack *sw, return 0; } +static long +ia64_sync_kernel_rbs (struct task_struct *child, struct switch_stack *sw, + unsigned long user_rbs_start, unsigned long user_rbs_end) +{ + unsigned long addr, val; + long ret; + + /* now copy word for word from user rbs to kernel rbs: */ + for (addr = user_rbs_start; addr < user_rbs_end; addr += 8) { + if (access_process_vm(child, addr, &val, sizeof(val), 0) + != sizeof(val)) + return -EIO; + + ret = ia64_poke(child, sw, user_rbs_end, addr, val); + if (ret < 0) + return ret; + } + return 0; +} + +typedef long (*syncfunc_t)(struct task_struct *, struct switch_stack *, + unsigned long, unsigned long); + +static void do_sync_rbs(struct unw_frame_info *info, void *arg) +{ + struct pt_regs *pt; + unsigned long urbs_end; + syncfunc_t fn = arg; + + if (unw_unwind_to_user(info) < 0) + return; + pt = task_pt_regs(info->task); + urbs_end = ia64_get_user_rbs_end(info->task, pt, NULL); + + fn(info->task, info->sw, pt->ar_bspstore, urbs_end); +} + +/* + * when a thread is stopped (ptraced), debugger might change thread's user + * stack (change memory directly), and we must avoid the RSE stored in kernel + * to override user stack (user space's RSE is newer than kernel's in the + * case). To workaround the issue, we copy kernel RSE to user RSE before the + * task is stopped, so user RSE has updated data. we then copy user RSE to + * kernel after the task is resummed from traced stop and kernel will use the + * newer RSE to return to user. TIF_RESTORE_RSE is the flag to indicate we need + * synchronize user RSE to kernel. + */ +void ia64_ptrace_stop(void) +{ + if (test_and_set_tsk_thread_flag(current, TIF_RESTORE_RSE)) + return; + tsk_set_notify_resume(current); + unw_init_running(do_sync_rbs, ia64_sync_user_rbs); +} + +/* + * This is called to read back the register backing store. + */ +void ia64_sync_krbs(void) +{ + clear_tsk_thread_flag(current, TIF_RESTORE_RSE); + tsk_clear_notify_resume(current); + + unw_init_running(do_sync_rbs, ia64_sync_kernel_rbs); +} + static inline int thread_matches (struct task_struct *thread, unsigned long addr) { @@ -1422,6 +1488,7 @@ sys_ptrace (long request, pid_t pid, unsigned long addr, unsigned long data) struct task_struct *child; struct switch_stack *sw; long ret; + struct unw_frame_info info; lock_kernel(); ret = -EPERM; @@ -1453,6 +1520,8 @@ sys_ptrace (long request, pid_t pid, unsigned long addr, unsigned long data) if (request == PTRACE_ATTACH) { ret = ptrace_attach(child); + if (!ret) + arch_ptrace_attach(child); goto out_tsk; } @@ -1481,6 +1550,11 @@ sys_ptrace (long request, pid_t pid, unsigned long addr, unsigned long data) /* write the word at location addr */ urbs_end = ia64_get_user_rbs_end(child, pt, NULL); ret = ia64_poke(child, sw, urbs_end, addr, data); + + /* Make sure user RBS has the latest data */ + unw_init_from_blocked_task(&info, child); + do_sync_rbs(&info, ia64_sync_user_rbs); + goto out_tsk; case PTRACE_PEEKUSR: @@ -1634,6 +1708,10 @@ syscall_trace_enter (long arg0, long arg1, long arg2, long arg3, && (current->ptrace & PT_PTRACED)) syscall_trace(); + /* copy user rbs to kernel rbs */ + if (test_thread_flag(TIF_RESTORE_RSE)) + ia64_sync_krbs(); + if (unlikely(current->audit_context)) { long syscall; int arch; @@ -1671,4 +1749,8 @@ syscall_trace_leave (long arg0, long arg1, long arg2, long arg3, || test_thread_flag(TIF_SINGLESTEP)) && (current->ptrace & PT_PTRACED)) syscall_trace(); + + /* copy user rbs to kernel rbs */ + if (test_thread_flag(TIF_RESTORE_RSE)) + ia64_sync_krbs(); } |