litmus-rt.git - The LITMUS^RT kernel.

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author	Benjamin Herrenschmidt <benh@kernel.crashing.org>	2009-03-10 19:45:17 -0400
committer	Benjamin Herrenschmidt <benh@kernel.crashing.org>	2009-03-10 19:48:56 -0400
commit	d801cec70d69d2d4121e133edd5c3237fe0e0078 (patch)
tree	777e46af2366ce8ffa0dd5c1a9fcead8b6ef5fdb /fs/debugfs/file.c
parent	187cfc439f7b1a7c91ff72d561b2a7c9c0b83431 (diff)

radeonfb/aty128fb: Disable broken early resume hook for PowerBooks

radeonfb and aty128fb have a special hook called by the PowerMac platform code very very early on resume from sleep to bring the screen back. This is useful for debugging wakup problems, but unfortunately, this also became a source of problems of its own. The hook is called extremely early, with interrupts still off, and the code path involved with that code nowadays rely on things like taking mutexes, GFP_KERNEL allocations, etc... In addition, the driver now relies on the PCI core to restore the standard config space before calling resume which doesn't happen with this early code path. I'm keeping the code in but commented out along with a fixup call to pci_restore_state(). The reason is that I still want to make it easy to re-enable temporarily to track wake up problems, and it's possible that I can revive it at some stage if we make sleeping things save to call in early resume using a system state. In the meantime, this should fix several reported regressions. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Diffstat (limited to 'fs/debugfs/file.c')

0 files changed, 0 insertions, 0 deletions

/* * linux/kernel/ptrace.c * * (C) Copyright 1999 Linus Torvalds * * Common interfaces for "ptrace()" which we do not want * to continually duplicate across every architecture. */ #include <linux/capability.h> #include <linux/module.h> #include <linux/sched.h> #include <linux/errno.h> #include <linux/mm.h> #include <linux/highmem.h> #include <linux/pagemap.h> #include <linux/ptrace.h> #include <linux/security.h> #include <linux/signal.h> #include <linux/audit.h> #include <linux/pid_namespace.h> #include <linux/syscalls.h> #include <linux/uaccess.h> #include <linux/regset.h> #include <linux/hw_breakpoint.h> /* * ptrace a task: make the debugger its new parent and * move it to the ptrace list. * * Must be called with the tasklist lock write-held. */ void __ptrace_link(struct task_struct *child, struct task_struct *new_parent) { BUG_ON(!list_empty(&child->ptrace_entry)); list_add(&child->ptrace_entry, &new_parent->ptraced); child->parent = new_parent; } /** * __ptrace_unlink - unlink ptracee and restore its execution state * @child: ptracee to be unlinked * * Remove @child from the ptrace list, move it back to the original parent, * and restore the execution state so that it conforms to the group stop * state. * * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer * exiting. For PTRACE_DETACH, unless the ptracee has been killed between * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED. * If the ptracer is exiting, the ptracee can be in any state. * * After detach, the ptracee should be in a state which conforms to the * group stop. If the group is stopped or in the process of stopping, the * ptracee should be put into TASK_STOPPED; otherwise, it should be woken * up from TASK_TRACED. * * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED, * it goes through TRACED -> RUNNING -> STOPPED transition which is similar * to but in the opposite direction of what happens while attaching to a * stopped task. However, in this direction, the intermediate RUNNING * state is not hidden even from the current ptracer and if it immediately * re-attaches and performs a WNOHANG wait(2), it may fail. * * CONTEXT: * write_lock_irq(tasklist_lock) */ void __ptrace_unlink(struct task_struct *child) { BUG_ON(!child->ptrace); child->ptrace = 0; child->parent = child->real_parent; list_del_init(&child->ptrace_entry); spin_lock(&child->sighand->siglock); /* * Reinstate GROUP_STOP_PENDING if group stop is in effect and * @child isn't dead. */ if (!(child->flags & PF_EXITING) && (child->signal->flags & SIGNAL_STOP_STOPPED || child->signal->group_stop_count)) child->group_stop |= GROUP_STOP_PENDING; /* * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick * @child in the butt. Note that @resume should be used iff @child * is in TASK_TRACED; otherwise, we might unduly disrupt * TASK_KILLABLE sleeps. */ if (child->group_stop & GROUP_STOP_PENDING || task_is_traced(child)) signal_wake_up(child, task_is_traced(child)); spin_unlock(&child->sighand->siglock); } /* * Check that we have indeed attached to the thing.. */ int ptrace_check_attach(struct task_struct *child, int kill) { int ret = -ESRCH; /* * We take the read lock around doing both checks to close a * possible race where someone else was tracing our child and * detached between these two checks. After this locked check, * we are sure that this is our traced child and that can only * be changed by us so it's not changing right after this. */ read_lock(&tasklist_lock); if ((child->ptrace & PT_PTRACED) && child->parent == current) { /* * child->sighand can't be NULL, release_task() * does ptrace_unlink() before __exit_signal(). */ spin_lock_irq(&child->sighand->siglock); WARN_ON_ONCE(task_is_stopped(child)); if (task_is_traced(child) || kill) ret = 0; spin_unlock_irq(&child->sighand->siglock); } read_unlock(&tasklist_lock); if (!ret && !kill) ret = wait_task_inactive(child, TASK_TRACED) ? 0 : -ESRCH; /* All systems go.. */ return ret; } int __ptrace_may_access(struct task_struct *task, unsigned int mode) { const struct cred *cred = current_cred(), *tcred; /* May we inspect the given task? * This check is used both for attaching with ptrace * and for allowing access to sensitive information in /proc. * * ptrace_attach denies several cases that /proc allows * because setting up the necessary parent/child relationship * or halting the specified task is impossible. */ int dumpable = 0; /* Don't let security modules deny introspection */ if (task == current) return 0; rcu_read_lock(); tcred = __task_cred(task); if (cred->user->user_ns == tcred->user->user_ns && (cred->uid == tcred->euid && cred->uid == tcred->suid && cred->uid == tcred->uid && cred->gid == tcred->egid && cred->gid == tcred->sgid && cred->gid == tcred->gid)) goto ok; if (ns_capable(tcred->user->user_ns, CAP_SYS_PTRACE)) goto ok; rcu_read_unlock(); return -EPERM; ok: rcu_read_unlock(); smp_rmb(); if (task->mm) dumpable = get_dumpable(task->mm); if (!dumpable && !task_ns_capable(task, CAP_SYS_PTRACE)) return -EPERM; return security_ptrace_access_check(task, mode); } bool ptrace_may_access(struct task_struct *task, unsigned int mode) { int err; task_lock(task); err = __ptrace_may_access(task, mode); task_unlock(task); return !err; } static int ptrace_attach(struct task_struct *task) { bool wait_trap = false; int retval; audit_ptrace(task); retval = -EPERM; if (unlikely(task->flags & PF_KTHREAD)) goto out; if (same_thread_group(task, current)) goto out; /* * Protect exec's credential calculations against our interference; * interference; SUID, SGID and LSM creds get determined differently * under ptrace. */ retval = -ERESTARTNOINTR; if (mutex_lock_interruptible(&task->signal->cred_guard_mutex)) goto out; task_lock(task); retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH); task_unlock(task); if (retval) goto unlock_creds; write_lock_irq(&tasklist_lock); retval = -EPERM; if (unlikely(task->exit_state)) goto unlock_tasklist; if (task->ptrace) goto unlock_tasklist; task->ptrace = PT_PTRACED; if (task_ns_capable(task, CAP_SYS_PTRACE)) task->ptrace |= PT_PTRACE_CAP; __ptrace_link(task, current); send_sig_info(SIGSTOP, SEND_SIG_FORCED, task); spin_lock(&task->sighand->siglock); /* * If the task is already STOPPED, set GROUP_STOP_PENDING and * TRAPPING, and kick it so that it transits to TRACED. TRAPPING * will be cleared if the child completes the transition or any * event which clears the group stop states happens. We'll wait * for the transition to complete before returning from this * function. * * This hides STOPPED -> RUNNING -> TRACED transition from the * attaching thread but a different thread in the same group can * still observe the transient RUNNING state. IOW, if another * thread's WNOHANG wait(2) on the stopped tracee races against * ATTACH, the wait(2) may fail due to the transient RUNNING. * * The following task_is_stopped() test is safe as both transitions * in and out of STOPPED are protected by siglock. */ if (task_is_stopped(task)) { task->group_stop |= GROUP_STOP_PENDING | GROUP_STOP_TRAPPING; signal_wake_up(task, 1); wait_trap = true; } spin_unlock(&task->sighand->siglock); retval = 0; unlock_tasklist: write_unlock_irq(&tasklist_lock); unlock_creds: mutex_unlock(&task->signal->cred_guard_mutex); out: if (wait_trap) wait_event(current->signal->wait_chldexit, !(task->group_stop & GROUP_STOP_TRAPPING)); return retval; } /** * ptrace_traceme -- helper for PTRACE_TRACEME * * Performs checks and sets PT_PTRACED. * Should be used by all ptrace implementations for PTRACE_TRACEME. */ static int ptrace_traceme(void) { int ret = -EPERM; write_lock_irq(&tasklist_lock); /* Are we already being traced? */ if (!current->ptrace) { ret = security_ptrace_traceme(current->parent); /* * Check PF_EXITING to ensure ->real_parent has not passed * exit_ptrace(). Otherwise we don't report the error but * pretend ->real_parent untraces us right after return. */ if (!ret && !(current->real_parent->flags & PF_EXITING)) { current->ptrace = PT_PTRACED; __ptrace_link(current, current->real_parent); } } write_unlock_irq(&tasklist_lock); return ret; } /* * Called with irqs disabled, returns true if childs should reap themselves. */ static int ignoring_children(struct sighand_struct *sigh) { int ret; spin_lock(&sigh->siglock); ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) || (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT); spin_unlock(&sigh->siglock); return ret; } /* * Called with tasklist_lock held for writing. * Unlink a traced task, and clean it up if it was a traced zombie. * Return true if it needs to be reaped with release_task(). * (We can't call release_task() here because we already hold tasklist_lock.) * * If it's a zombie, our attachedness prevented normal parent notification * or self-reaping. Do notification now if it would have happened earlier. * If it should reap itself, return true. * * If it's our own child, there is no notification to do. But if our normal * children self-reap, then this child was prevented by ptrace and we must * reap it now, in that case we must also wake up sub-threads sleeping in * do_wait(). */ static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p) { __ptrace_unlink(p); if (p->exit_state == EXIT_ZOMBIE) { if (!task_detached(p) && thread_group_empty(p)) { if (!same_thread_group(p->real_parent, tracer)) do_notify_parent(p, p->exit_signal); else if (ignoring_children(tracer->sighand)) { __wake_up_parent(p, tracer); p->exit_signal = -1; } } if (task_detached(p)) { /* Mark it as in the process of being reaped. */ p->exit_state = EXIT_DEAD; return true; } } return false; } static int ptrace_detach(struct task_struct *child, unsigned int data) { bool dead = false; if (!valid_signal(data)) return -EIO; /* Architecture-specific hardware disable .. */ ptrace_disable(child); clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); write_lock_irq(&tasklist_lock); /* * This child can be already killed. Make sure de_thread() or * our sub-thread doing do_wait() didn't do release_task() yet. */ if (child->ptrace) { child->exit_code = data; dead = __ptrace_detach(current, child); } write_unlock_irq(&tasklist_lock); if (unlikely(dead)) release_task(child); return 0; } /* * Detach all tasks we were using ptrace on. Called with tasklist held * for writing, and returns with it held too. But note it can release * and reacquire the lock. */ void exit_ptrace(struct task_struct *tracer) __releases(&tasklist_lock) __acquires(&tasklist_lock) { struct task_struct *p, *n; LIST_HEAD(ptrace_dead); if (likely(list_empty(&tracer->ptraced))) return; list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) { if (__ptrace_detach(tracer, p)) list_add(&p->ptrace_entry, &ptrace_dead); } write_unlock_irq(&tasklist_lock); BUG_ON(!list_empty(&tracer->ptraced)); list_for_each_entry_safe(p, n, &ptrace_dead, ptrace_entry) { list_del_init(&p->ptrace_entry); release_task(p); } write_lock_irq(&tasklist_lock); } int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len) { int copied = 0; while (len > 0) { char buf[128]; int this_len, retval; this_len = (len > sizeof(buf)) ? sizeof(buf) : len; retval = access_process_vm(tsk, src, buf, this_len, 0); if (!retval) { if (copied) break; return -EIO; } if (copy_to_user(dst, buf, retval)) return -EFAULT; copied += retval; src += retval; dst += retval; len -= retval; } return copied; } int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len) { int copied = 0; while (len > 0) { char buf[128]; int this_len, retval; this_len = (len > sizeof(buf)) ? sizeof(buf) : len; if (copy_from_user(buf, src, this_len)) return -EFAULT; retval = access_process_vm(tsk, dst, buf, this_len, 1); if (!retval) { if (copied) break; return -EIO; } copied += retval; src += retval; dst += retval; len -= retval; } return copied; } static int ptrace_setoptions(struct task_struct *child, unsigned long data) { child->ptrace &= ~PT_TRACE_MASK; if (data & PTRACE_O_TRACESYSGOOD) child->ptrace |= PT_TRACESYSGOOD; if (data & PTRACE_O_TRACEFORK) child->ptrace |= PT_TRACE_FORK; if (data & PTRACE_O_TRACEVFORK) child->ptrace |= PT_TRACE_VFORK; if (data & PTRACE_O_TRACECLONE) child->ptrace |= PT_TRACE_CLONE; if (data & PTRACE_O_TRACEEXEC) child->ptrace |= PT_TRACE_EXEC; if (data & PTRACE_O_TRACEVFORKDONE) child->ptrace |= PT_TRACE_VFORK_DONE; if (data & PTRACE_O_TRACEEXIT) child->ptrace |= PT_TRACE_EXIT; return (data & ~PTRACE_O_MASK) ? -EINVAL : 0; } static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info) { unsigned long flags; int error = -ESRCH; if (lock_task_sighand(child, &flags)) { error = -EINVAL; if (likely(child->last_siginfo != NULL)) { *info = *child->last_siginfo; error = 0; } unlock_task_sighand(child, &flags); } return error; } static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info) { unsigned long flags; int error = -ESRCH; if (lock_task_sighand(child, &flags)) { error = -EINVAL; if (likely(child->last_siginfo != NULL)) { *child->last_siginfo = *info; error = 0; } unlock_task_sighand(child, &flags); } return error; } #ifdef PTRACE_SINGLESTEP #define is_singlestep(request) ((request) == PTRACE_SINGLESTEP) #else #define is_singlestep(request) 0 #endif #ifdef PTRACE_SINGLEBLOCK #define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK) #else #define is_singleblock(request) 0 #endif #ifdef PTRACE_SYSEMU #define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP) #else #define is_sysemu_singlestep(request) 0 #endif static int ptrace_resume(struct task_struct *child, long request, unsigned long data) { if (!valid_signal(data)) return -EIO; if (request == PTRACE_SYSCALL) set_tsk_thread_flag(child, TIF_SYSCALL_TRACE); else clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); #ifdef TIF_SYSCALL_EMU if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP) set_tsk_thread_flag(child, TIF_SYSCALL_EMU); else clear_tsk_thread_flag(child, TIF_SYSCALL_EMU); #endif if (is_singleblock(request)) { if (unlikely(!arch_has_block_step())) return -EIO; user_enable_block_step(child); } else if (is_singlestep(request) || is_sysemu_singlestep(request)) { if (unlikely(!arch_has_single_step())) return -EIO; user_enable_single_step(child); } else { user_disable_single_step(child); } child->exit_code = data; wake_up_state(child, __TASK_TRACED); return 0; } #ifdef CONFIG_HAVE_ARCH_TRACEHOOK static const struct user_regset * find_regset(const struct user_regset_view *view, unsigned int type) { const struct user_regset *regset; int n; for (n = 0; n < view->n; ++n) { regset = view->regsets + n; if (regset->core_note_type == type) return regset; } return NULL; } static int ptrace_regset(struct task_struct *task, int req, unsigned int type, struct iovec *kiov) { const struct user_regset_view *view = task_user_regset_view(task); const struct user_regset *regset = find_regset(view, type); int regset_no; if (!regset || (kiov->iov_len % regset->size) != 0) return -EINVAL; regset_no = regset - view->regsets; kiov->iov_len = min(kiov->iov_len, (__kernel_size_t) (regset->n * regset->size)); if (req == PTRACE_GETREGSET) return copy_regset_to_user(task, view, regset_no, 0, kiov->iov_len, kiov->iov_base); else return copy_regset_from_user(task, view, regset_no, 0, kiov->iov_len, kiov->iov_base); } #endif int ptrace_request(struct task_struct *child, long request, unsigned long addr, unsigned long data) { int ret = -EIO; siginfo_t siginfo; void __user *datavp = (void __user *) data; unsigned long __user *datalp = datavp; switch (request) { case PTRACE_PEEKTEXT: case PTRACE_PEEKDATA: return generic_ptrace_peekdata(child, addr, data); case PTRACE_POKETEXT: case PTRACE_POKEDATA: return generic_ptrace_pokedata(child, addr, data); #ifdef PTRACE_OLDSETOPTIONS case PTRACE_OLDSETOPTIONS: #endif case PTRACE_SETOPTIONS: ret = ptrace_setoptions(child, data); break; case PTRACE_GETEVENTMSG: ret = put_user(child->ptrace_message, datalp); break; case PTRACE_GETSIGINFO: ret = ptrace_getsiginfo(child, &siginfo); if (!ret) ret = copy_siginfo_to_user(datavp, &siginfo); break; case PTRACE_SETSIGINFO: if (copy_from_user(&siginfo, datavp, sizeof siginfo)) ret = -EFAULT; else ret = ptrace_setsiginfo(child, &siginfo); break; case PTRACE_DETACH: /* detach a process that was attached. */ ret = ptrace_detach(child, data); break; #ifdef CONFIG_BINFMT_ELF_FDPIC case PTRACE_GETFDPIC: { struct mm_struct *mm = get_task_mm(child); unsigned long tmp = 0; ret = -ESRCH; if (!mm) break; switch (addr) { case PTRACE_GETFDPIC_EXEC: tmp = mm->context.exec_fdpic_loadmap; break; case PTRACE_GETFDPIC_INTERP: tmp = mm->context.interp_fdpic_loadmap; break; default: break; } mmput(mm); ret = put_user(tmp, datalp); break; } #endif #ifdef PTRACE_SINGLESTEP case PTRACE_SINGLESTEP: #endif #ifdef PTRACE_SINGLEBLOCK case PTRACE_SINGLEBLOCK: #endif #ifdef PTRACE_SYSEMU case PTRACE_SYSEMU: case PTRACE_SYSEMU_SINGLESTEP: #endif case PTRACE_SYSCALL: case PTRACE_CONT:


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