powerpc: Prepare for IRQ entry exit

Move interrupt entry and exit helper routines from interrupt.h into the
PowerPC-specific entry-common.h header as a preparatory step for enabling
the generic entry/exit framework.

This consolidation places all PowerPC interrupt entry/exit handling in a
single common header, aligning with the generic entry infrastructure.
The helpers provide architecture-specific handling for interrupt and NMI
entry/exit sequences, including:

 - arch_interrupt_enter/exit_prepare()
 - arch_interrupt_async_enter/exit_prepare()
 - arch_interrupt_nmi_enter/exit_prepare()
 - Supporting helpers such as nap_adjust_return(), check_return_regs_valid(),
   debug register maintenance, and soft mask handling.

The functions are copied verbatim from interrupt.h.Subsequent patches will
integrate these routines into the generic entry/exit flow.

No functional change intended.

Signed-off-by: Mukesh Kumar Chaurasiya <mchauras@linux.ibm.com>
Tested-by: Samir M <samir@linux.ibm.com>
Tested-by: David Gow <davidgow@google.com>
Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Reviewed-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20260427122742.210074-7-mkchauras@gmail.com

0 files changed, 0 insertions, 0 deletions