From: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
To: Yoshinori Sato <ysato@users.sourceforge.jp>,
Rich Felker <dalias@libc.org>, Karl Nasrallah <knnspeed@aol.com>
Cc: Linux-SH <linux-sh@vger.kernel.org>,
Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
Geert Uytterhoeven <geert+renesas@glider.be>
Subject: [PATCH v2 1/3] sh: fixup strncpy() warning and add missing padding
Date: 19 Dec 2019 10:23:11 +0900 [thread overview]
Message-ID: <87v9qdyups.wl-kuninori.morimoto.gx@renesas.com> (raw)
In-Reply-To: <87woatyutt.wl-kuninori.morimoto.gx@renesas.com>
From: Karl Nasrallah <knnspeed@aol.com>
Current SH will get below warning at strncpy()
In file included from ${LINUX}/arch/sh/include/asm/string.h:3,
from ${LINUX}/include/linux/string.h:20,
from ${LINUX}/include/linux/bitmap.h:9,
from ${LINUX}/include/linux/nodemask.h:95,
from ${LINUX}/include/linux/mmzone.h:17,
from ${LINUX}/include/linux/gfp.h:6,
from ${LINUX}/innclude/linux/slab.h:15,
from ${LINUX}/linux/drivers/mmc/host/vub300.c:38:
${LINUX}/drivers/mmc/host/vub300.c: In function 'new_system_port_status':
${LINUX}/arch/sh/include/asm/string_32.h:51:42: warning: array subscript\
80 is above array bounds of 'char[26]' [-Warray-bounds]
: "0" (__dest), "1" (__src), "r" (__src+__n)
~~~~~^~~~
And current implementation is missing padding which strncpy()
should support.
This patch solves these 2 issues.
Signed-off-by: Karl Nasrallah <knnspeed@aol.com>
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
---
v1 -> v2
- tidyup git-log
- tidyup 80char
- tidyup Subject
arch/sh/include/asm/string_32.h | 56 +++++++++++++++++++++++++++--------------
1 file changed, 37 insertions(+), 19 deletions(-)
diff --git a/arch/sh/include/asm/string_32.h b/arch/sh/include/asm/string_32.h
index 3558b1d..4978f6e 100644
--- a/arch/sh/include/asm/string_32.h
+++ b/arch/sh/include/asm/string_32.h
@@ -31,27 +31,45 @@ static inline char *strcpy(char *__dest, const char *__src)
#define __HAVE_ARCH_STRNCPY
static inline char *strncpy(char *__dest, const char *__src, size_t __n)
{
- register char *__xdest = __dest;
- unsigned long __dummy;
+ char * retval = __dest;
+ const char * __dest_end = __dest + __n - 1;
+ /* size_t is always unsigned */
if (__n == 0)
- return __xdest;
-
- __asm__ __volatile__(
- "1:\n"
- "mov.b @%1+, %2\n\t"
- "mov.b %2, @%0\n\t"
- "cmp/eq #0, %2\n\t"
- "bt/s 2f\n\t"
- " cmp/eq %5,%1\n\t"
- "bf/s 1b\n\t"
- " add #1, %0\n"
- "2:"
- : "=r" (__dest), "=r" (__src), "=&z" (__dummy)
- : "0" (__dest), "1" (__src), "r" (__src+__n)
- : "memory", "t");
-
- return __xdest;
+ return retval;
+
+ /*
+ * Some notes:
+ * - cmp/eq #imm8,r0 is its own instruction
+ * - incrementing dest and comparing to dest_end handles the size
+ * parameter in only one instruction
+ * - mov.b R0,@Rn+ is SH2A only, but we can fill a delay slot with
+ * "add #1,%[dest]"
+ */
+
+ __asm__ __volatile__ (
+ "strncpy_start:\n\t"
+ "mov.b @%[src]+,r0\n\t"
+ "cmp/eq #0,r0\n\t"
+ "bt.s strncpy_pad\n\t"
+ "cmp/eq %[dest],%[dest_end]\n\t"
+ "bt.s strncpy_end\n\t"
+ "mov.b r0,@%[dest]\n\t"
+ "bra strncpy_start\n\t"
+ "add #1,%[dest]\n\t"
+ "strncpy_pad:\n\t"
+ "bt.s strncpy_end\n\t"
+ "mov.b r0,@%[dest]\n\t"
+ "add #1,%[dest]\n\t"
+ "bra strncpy_pad\n\t"
+ "cmp/eq %[dest],%[dest_end]\n\t"
+ "strncpy_end:\n\t"
+ : [src] "+r" (__src), [dest] "+r" (__dest)
+ : [dest_end] "r" (__dest_end)
+ : "r0","t","memory"
+ );
+
+ return retval;
}
#define __HAVE_ARCH_STRCMP
--
2.7.4
next prev parent reply other threads:[~2019-12-19 1:23 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-19 1:20 [PATCH v2 0/3] sh: fixup strncpy() Kuninori Morimoto
2019-12-19 1:23 ` Kuninori Morimoto [this message]
2019-12-19 1:24 ` [PATCH v2 2/3] sh: fixup strncpy() warning and add missing padding Kuninori Morimoto
2019-12-19 1:24 ` [PATCH 3/3] sh: use generic strncpy() Kuninori Morimoto
2019-12-20 15:42 ` [PATCH v2 0/3] sh: fixup strncpy() Yoshinori Sato
2019-12-21 2:35 ` Karl Nasrallah
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