diff mbox series

[v8,04/30] powerpc/xmon: Use bitwise calculations in_breakpoint_table()

Message ID 20200506034050.24806-5-jniethe5@gmail.com (mailing list archive)
State Accepted
Commit 5a7fdcab54ef17c395fc47e73c828a1432e51683
Headers show
Series Initial Prefixed Instruction support | expand

Checks

Context Check Description
snowpatch_ozlabs/apply_patch success Successfully applied on branch powerpc/merge (1bc92fe3175eb26ff37e580c0383d7a9abe06835)
snowpatch_ozlabs/checkpatch success total: 0 errors, 0 warnings, 0 checks, 10 lines checked
snowpatch_ozlabs/needsstable success Patch has no Fixes tags

Commit Message

Jordan Niethe May 6, 2020, 3:40 a.m. UTC 
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>
Reviewed-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
---
v6: New to series
---
 arch/powerpc/xmon/xmon.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index 4ecb7e73b017..c52b117640f2 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -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);
 }