Commit 5a7fdcab authored May 06, 2020 by Jordan Niethe Committed by Michael Ellerman May 19, 2020

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

parent 4eff2b4f

arch/powerpc/xmon/xmon.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -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);
		}