Rewrite the PDC console to become an early console.
Beside the fact that now boot information is visible until another
(text- or graphics) console takes over, this benefits as well machines
with a yet-unsupported STI console and kgdb.

Signed-off-by: Helge Deller <deller@gmx.de>

Various spelling mistakes in comments.
Detected with the help of Coccinelle.

Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Signed-off-by: Helge Deller <deller@gmx.de>

This patch changes the kprobe and kretprobe feature to use another
break instruction instead of relying on the hardware single-step
feature.
That way those kprobes now work in qemu as well, because in qemu we
don't emulate yet single-stepping.

Signed-off-by: Helge Deller <deller@gmx.de>

Currently, the parisc kernel does not fully support non-access TLB
fault handling for probe instructions. In the fast path, we set the
target register to zero if it is not a shadowed register. The slow
path is not implemented, so we call do_page_fault. The architecture
indicates that non-access faults should not cause a page fault from
disk.

This change adds to code to provide non-access fault support for
probe instructions. It also modifies the handling of faults on
userspace so that if the address lies in a valid VMA and the access
type matches that for the VMA, the probe target register is set to
one. Otherwise, the target register is set to zero.

This was done to make probe instructions more useful for userspace.
Probe instructions are not very useful if they set the target register
to zero whenever a page is not present in memory. Nominally, the
purpose of the probe instruction is determine whether read or write
access to a given address is allowed.

This fixes a problem in function pointer comparison noticed in the
glibc testsuite (stdio-common/tst-vfprintf-user-type). The same
problem is likely in glibc (_dl_lookup_address).

V2 adds flush and lpa instruction support to handle_nadtlb_fault.

Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>

Pull signal/exit/ptrace updates from Eric Biederman:
 "This set of changes deletes some dead code, makes a lot of cleanups
  which hopefully make the code easier to follow, and fixes bugs found
  along the way.

  The end-game which I have not yet reached yet is for fatal signals
  that generate coredumps to be short-circuit deliverable from
  complete_signal, for force_siginfo_to_task not to require changing
  userspace configured signal delivery state, and for the ptrace stops
  to always happen in locations where we can guarantee on all
  architectures that the all of the registers are saved and available on
  the stack.

  Removal of profile_task_ext, profile_munmap, and profile_handoff_task
  are the big successes for dead code removal this round.

  A bunch of small bug fixes are included, as most of the issues
  reported were small enough that they would not affect bisection so I
  simply added the fixes and did not fold the fixes into the changes
  they were fixing.

  There was a bug that broke coredumps piped to systemd-coredump. I
  dropped the change that caused that bug and replaced it entirely with
  something much more restrained. Unfortunately that required some
  rebasing.

  Some successes after this set of changes: There are few enough calls
  to do_exit to audit in a reasonable amount of time. The lifetime of
  struct kthread now matches the lifetime of struct task, and the
  pointer to struct kthread is no longer stored in set_child_tid. The
  flag SIGNAL_GROUP_COREDUMP is removed. The field group_exit_task is
  removed. Issues where task->exit_code was examined with
  signal->group_exit_code should been examined were fixed.

  There are several loosely related changes included because I am
  cleaning up and if I don't include them they will probably get lost.

  The original postings of these changes can be found at:
     https://lkml.kernel.org/r/87a6ha4zsd.fsf@email.froward.int.ebiederm.org
     https://lkml.kernel.org/r/87bl1kunjj.fsf@email.froward.int.ebiederm.org
     https://lkml.kernel.org/r/87r19opkx1.fsf_-_@email.froward.int.ebiederm.org

  I trimmed back the last set of changes to only the obviously correct
  once. Simply because there was less time for review than I had hoped"

* 'signal-for-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (44 commits)
  ptrace/m68k: Stop open coding ptrace_report_syscall
  ptrace: Remove unused regs argument from ptrace_report_syscall
  ptrace: Remove second setting of PT_SEIZED in ptrace_attach
  taskstats: Cleanup the use of task->exit_code
  exit: Use the correct exit_code in /proc/<pid>/stat
  exit: Fix the exit_code for wait_task_zombie
  exit: Coredumps reach do_group_exit
  exit: Remove profile_handoff_task
  exit: Remove profile_task_exit & profile_munmap
  signal: clean up kernel-doc comments
  signal: Remove the helper signal_group_exit
  signal: Rename group_exit_task group_exec_task
  coredump: Stop setting signal->group_exit_task
  signal: Remove SIGNAL_GROUP_COREDUMP
  signal: During coredumps set SIGNAL_GROUP_EXIT in zap_process
  signal: Make coredump handling explicit in complete_signal
  signal: Have prepare_signal detect coredumps using signal->core_state
  signal: Have the oom killer detect coredumps using signal->core_state
  exit: Move force_uaccess back into do_exit
  exit: Guarantee make_task_dead leaks the tsk when calling do_task_exit
  ...

In handle_interruption(), we call faulthandler_disabled() to check whether the
fault handler is not disabled. If the fault handler is disabled, we immediately
call do_page_fault(). It then calls faulthandler_disabled(). If disabled,
do_page_fault() attempts to fixup the exception by jumping to no_context:

no_context:

        if (!user_mode(regs) && fixup_exception(regs)) {
                return;
        }

        parisc_terminate("Bad Address (null pointer deref?)", regs, code, address);

Apart from the error messages, the two blocks of code perform the same
function.

We can avoid two calls to faulthandler_disabled() by a simple revision
to the code in handle_interruption().

Note: I didn't try to fix the formatting of this code block.

Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>

When a trap 7 (Instruction access rights) occurs, this means the CPU
couldn't execute an instruction due to missing execute permissions on
the memory region.  In this case it seems the CPU didn't even fetched
the instruction from memory and thus did not store it in the cr19 (IIR)
register before calling the trap handler. So, the trap handler will find
some random old stale value in cr19.

This patch simply overwrites the stale IIR value with a constant magic
"bad food" value (0xbaadf00d), in the hope people don't start to try to
understand the various random IIR values in trap 7 dumps.

Noticed-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>

There are two big uses of do_exit.  The first is it's design use to be
the guts of the exit(2) system call.  The second use is to terminate
a task after something catastrophic has happened like a NULL pointer
in kernel code.

Add a function make_task_dead that is initialy exactly the same as
do_exit to cover the cases where do_exit is called to handle
catastrophic failure.  In time this can probably be reduced to just a
light wrapper around do_task_dead. For now keep it exactly the same so
that there will be no behavioral differences introducing this new
concept.

Replace all of the uses of do_exit that use it for catastraphic
task cleanup with make_task_dead to make it clear what the code
is doing.

As part of this rename rewind_stack_do_exit
rewind_stack_and_make_dead.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

If the previous context had interrupts disabled, we should better
keep them disabled. This was noticed in the unwinding code where
a copy_from_kernel_nofault() triggered a page fault, and after
the fixup by the page fault handler interrupts where suddenly
enabled.

Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>

This implements the CONFIG_THREAD_INFO_IN_TASK option.

With this change:
- before thread_info was part of the stack and located at the beginning of the stack
- now the thread_info struct is moved and located inside the task_struct structure
- the stack is allocated and handled like the major other platforms
- drop the cpu field of thread_info and use instead the one in task_struct

Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sven Schnelle <svens@stackframe.org>