linux.git/arch/parisc/kernel/unwind.c, branch for-next

parisc: Fix stack unwinder

2024-02-19T20:55:22+00:00

Debugging shows a large number of unaligned access traps in the unwinder
code. Code analysis reveals a number of issues with this code:

- handle_interruption is passed twice through
  dereference_kernel_function_descriptor()
- ret_from_kernel_thread, syscall_exit, intr_return,
  _switch_to_ret, and _call_on_stack are passed through
  dereference_kernel_function_descriptor() even though they are
  not declared as function pointers.

To fix the problems, drop one of the calls to
dereference_kernel_function_descriptor() for handle_interruption,
and compare the other pointers directly.

Fixes: 6414b30b39f9 ("parisc: unwind: Avoid missing prototype warning for handle_interruption()")
Fixes: 8e0ba125c2bf ("parisc/unwind: fix unwinder when CONFIG_64BIT is enabled")
Cc: Helge Deller 
Cc: Sven Schnelle 
Cc: John David Anglin 
Cc: Charlie Jenkins 
Cc: David Laight 
Signed-off-by: Guenter Roeck 
Signed-off-by: Helge Deller

parisc: unwind: Avoid missing prototype warning for handle_interruption()

2023-07-03T16:56:03+00:00

Signed-off-by: Helge Deller

parisc: unwind: Mark start and stop variables __maybe_unused

2023-06-30T15:14:15+00:00

Signed-off-by: Helge Deller

parisc: Move thread_info into task struct

2021-11-01T06:35:59+00:00

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 
Signed-off-by: Sven Schnelle

parisc/unwind: fix unwinder when CONFIG_64BIT is enabled

2021-11-01T06:35:58+00:00

With 64 bit kernels unwind_special() is not working because
it compares the pc to the address of the function descriptor.
Add a helper function that compares pc with the dereferenced
address. This fixes all of the backtraces on my c8000. Without
this changes, a lot of backtraces are missing in kdb or the
show-all-tasks command from /proc/sysrq-trigger.

Signed-off-by: Sven Schnelle 
Signed-off-by: Helge Deller

parisc/unwind: use copy_from_kernel_nofault()

2021-10-30T21:11:00+00:00

I have no idea why get_user() is used there, but we're unwinding the
kernel stack, so we should use copy_from_kernel_nofault().

Signed-off-by: Sven Schnelle 
Signed-off-by: Helge Deller

parisc: Use __ro_after_init in unwind.c

2019-05-10T19:00:45+00:00

Signed-off-by: Helge Deller

parisc: Fix uninitialized variable usage in unwind.c

2018-10-16T09:37:29+00:00

As noticed by Dave Anglin, the last commit introduced a small bug where
the potentially uninitialized r struct is used instead of the regs
pointer as input for unwind_frame_init(). Fix it.

Signed-off-by: Helge Deller 
Reported-by: John David Anglin

parisc: Fix boot failure of 64-bit kernel

2018-08-21T12:32:44+00:00

Commit c8921d72e390 ("parisc: Fix and improve kernel stack unwinding")
broke booting of 64-bit kernels. On 64-bit kernels function pointers are
actually function descriptors which require dereferencing. In this patch
we instead declare functions in assembly code which are referenced from
C-code as external data pointers with the ENTRY() macro and thus can use
a simple external reference to the functions.

Signed-off-by: Helge Deller 
Fixes: c8921d72e390 ("parisc: Fix and improve kernel stack unwinding")

parisc: Consolidate unwind initialization calls

2018-08-17T15:00:08+00:00

Signed-off-by: Helge Deller