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powerpc/watchpoint: Fix length calculation for unaligned target

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Watchpoint match range is always doubleword(8 bytes) aligned on
powerpc. If the given range is crossing doubleword boundary, we need
to increase the length such that next doubleword also get
covered. Ex,

          address   len = 6 bytes
                |=========.
   |------------v--|------v--------|
   | | | | | | | | | | | | | | | | |
   |---------------|---------------|
    <---8 bytes--->

In such case, current code configures hw as:
  start_addr = address & ~HW_BREAKPOINT_ALIGN
  len = 8 bytes

And thus read/write in last 4 bytes of the given range is ignored.
Fix this by including next doubleword in the length.

Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191017093204.7511-3-ravi.bangoria@linux.ibm.com
This commit is contained in:
Ravi Bangoria
2019-10-17 15:01:59 +05:30
committed by Michael Ellerman
parent b811be615c
commit b57aeab811
5 changed files with 56 additions and 23 deletions
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3
arch/powerpc/kernel/process.c
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@@ -715,6 +715,8 @@ static void set_debug_reg_defaults(struct thread_struct *thread)
{
thread->hw_brk.address = 0;
thread->hw_brk.type = 0;
thread->hw_brk.len = 0;
thread->hw_brk.hw_len = 0;
if (ppc_breakpoint_available())
set_breakpoint(&thread->hw_brk);
}
@@ -816,6 +818,7 @@ static inline bool hw_brk_match(struct arch_hw_breakpoint *a,
return false;
if (a->len != b->len)
return false;
/* no need to check hw_len. it's calculated from address and len */
return true;
}