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powerpc/xmon: Use bitwise calculations in_breakpoint_table() 

A modulo operation is used for calculating the current offset from a
breakpoint within the breakpoint table. As instruction lengths are
always a power of 2, this can be replaced with a bitwise 'and'. The
current check for word alignment can be replaced with checking that the
lower 2 bits are not set.

Suggested-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Alistair Popple <alistair@popple.id.au>
Link: https://lore.kernel.org/r/20200506034050.24806-5-jniethe5@gmail.com
This commit is contained in:
Jordan Niethe 2020-05-06 13:40:24 +10:00 committed by Michael Ellerman
parent 4eff2b4f32
commit 5a7fdcab54
1 changed files with 2 additions and 2 deletions
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4
arch/powerpc/xmon/xmon.c
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@ -857,8 +857,8 @@ static struct bpt *in_breakpoint_table(unsigned long nip, unsigned long *offp)
off = nip - (unsigned long)bpt_table;
if (off >= sizeof(bpt_table))
return NULL;
*offp = off % BPT_SIZE;
if (*offp != 0 && *offp != 4)
*offp = off & (BPT_SIZE - 1);
if (off & 3)
return NULL;
return bpts + (off / BPT_SIZE);
}