BACKPORT: arm64: Allow hw watchpoint at varied offset from base address

(cherry picked from commit b08fb180bb8802d1c599beb1acd6a3b26163b4f6)

ARM64 hardware supports watchpoint at any double word aligned address.
However, it can select any consecutive bytes from offset 0 to 7 from that
base address. For example, if base address is programmed as 0x420030 and
byte select is 0x1C, then access of 0x420032,0x420033 and 0x420034 will
generate a watchpoint exception.

Currently, we do not have such modularity. We can only program byte,
halfword, word and double word access exception from any base address.

This patch adds support to overcome above limitations.

Signed-off-by: Pratyush Anand <>
Signed-off-by: Will Deacon <>
Signed-off-by: Pavel Labath <>
[minor conflict in ptrace.c:ptrace_hbp_fill_attr_ctrl]
Change-Id: Id553398db73c4b6086cd59a5513df222c5f674f7
Bug: 30919905
3 files changed