arm64: hw_breakpoint: use target state to determine ABI behaviour
arm64: hw_breakpoint: use target state to determine ABI behaviour

The arm64 hw_breakpoint interface is slightly less flexible than its
32-bit counterpart, thanks to some changes in the architecture rendering
unaligned watchpoint addresses obselete for AArch64.

However, in a multi-arch environment (i.e. debugging a 32-bit target
with a 64-bit GDB under a 64-bit kernel), we need to provide a feature
compatible interface to GDB in order for debugging to function correctly.

This patch adds a new helper, is_compat_bp,  to our hw_breakpoint
implementation which changes the interface behaviour based on the
architecture of the debug target as opposed to the debugger itself.
This allows debugged to function as expected for multi-arch
configurations without relying on deprecated architectural behaviours
when debugging native applications.

Cc: Yao Qi <82697eede7783c80d18ae8c0d02575d32c9ac359@arm.com>
Signed-off-by: Will Deacon <b913f13ef92ac157955c954ccaaff7be065faba4@arm.com>
Signed-off-by: Catalin Marinas <15ce75b290ebaf27c3f9fd73ab848685ed3d8261@arm.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs