From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev list <linuxppc-dev@ozlabs.org>,
Akinobu Mita <mita@fixstars.com>
Subject: [PATCH] powerpc: Always use -mno-string
Date: Thu, 22 Mar 2007 17:23:44 +1100 [thread overview]
Message-ID: <1174544624.10836.24.camel@localhost.localdomain> (raw)
The string load/store instructions are causing more damage than
help on a lot of processors where they are microcoded and are
generally not good for the kernel to use. Let's make sure we
don't emit them on any powerpc variant.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
Ok, let's keep load/store multiple, they are only used on 32 bits
and are actually useful. string instructions are not though.
Index: linux-cell/arch/powerpc/Makefile
===================================================================
--- linux-cell.orig/arch/powerpc/Makefile 2007-03-22 17:02:42.000000000 +1100
+++ linux-cell/arch/powerpc/Makefile 2007-03-22 17:19:28.000000000 +1100
@@ -102,9 +102,9 @@ CFLAGS += $(call cc-option,-mno-altivec)
# kernel considerably.
CFLAGS += $(call cc-option,-funit-at-a-time)
-ifndef CONFIG_FSL_BOOKE
-CFLAGS += -mstring
-endif
+# Never use string load/store instructions as they are
+# often slow when they are implemented at all
+CFLAGS += -mno-string
ifeq ($(CONFIG_6xx),y)
CFLAGS += -mcpu=powerpc
next reply other threads:[~2007-03-22 6:24 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-22 6:23 Benjamin Herrenschmidt [this message]
2007-03-22 12:06 ` [PATCH] powerpc: Always use -mno-string Segher Boessenkool
2007-03-23 12:06 ` [PATCH] force -mno-string option on cell Akinobu Mita
2007-03-23 12:56 ` Segher Boessenkool
2007-03-23 19:38 ` Benjamin Herrenschmidt
2007-03-24 0:02 ` Segher Boessenkool
2007-03-23 20:46 ` [Cbe-oss-dev] " Arnd Bergmann
2007-03-26 12:00 ` Segher Boessenkool
2007-03-24 3:02 ` Paul Mackerras
2007-03-24 14:46 ` Segher Boessenkool
2007-03-23 13:37 ` Kumar Gala
2007-03-23 16:35 ` Segher Boessenkool
2007-03-23 19:46 ` Benjamin Herrenschmidt
2007-03-24 0:04 ` Segher Boessenkool
2007-03-26 8:54 ` Geert Uytterhoeven
2007-03-26 12:33 ` Segher Boessenkool
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