Le 08/07/2020 à 09:44, Jordan Niethe a écrit :
On Wed, Jul 8, 2020 at 2:53 PM Ravi Bangoria
<ravi.bango...@linux.ibm.com> wrote:

Milton Miller reported that we are aligning start and end address to
wrong size SZ_512M. It should be SZ_512. Fix that.

While doing this change I also found a case where ALIGN() comparison
fails. Within a given aligned range, ALIGN() of two addresses does not
match when start address is pointing to the first byte and end address
is pointing to any other byte except the first one. But that's not true
for ALIGN_DOWN(). ALIGN_DOWN() of any two addresses within that range
will always point to the first byte. So use ALIGN_DOWN() instead of

Fixes: e68ef121c1f4 ("powerpc/watchpoint: Use builtin ALIGN*() macros")
Reported-by: Milton Miller <milt...@us.ibm.com>
Signed-off-by: Ravi Bangoria <ravi.bango...@linux.ibm.com>
  arch/powerpc/kernel/hw_breakpoint.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/hw_breakpoint.c 
index 0000daf0e1da..031e6defc08e 100644
--- a/arch/powerpc/kernel/hw_breakpoint.c
+++ b/arch/powerpc/kernel/hw_breakpoint.c
@@ -419,7 +419,7 @@ static int hw_breakpoint_validate_len(struct 
arch_hw_breakpoint *hw)
         if (dawr_enabled()) {
                 max_len = DAWR_MAX_LEN;
                 /* DAWR region can't cross 512 bytes boundary */
-               if (ALIGN(start_addr, SZ_512M) != ALIGN(end_addr - 1, SZ_512M))
+               if (ALIGN_DOWN(start_addr, SZ_512) != ALIGN_DOWN(end_addr - 1, 
I wonder if you should use end_addr - 1, but rather end_addr. For example:
512 -> 1023, because of the -1, 1024 will now be included in this
range meaning 513 bytes?

end_addr is not part of the range.

If you want the range [512;1023], it means addr 512 len 512, that is end_addr = addr + len = 1024


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