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>
Subject: [PATCH] sh: use generic strncpy()
Date: 18 Dec 2019 16:32:45 +0900 [thread overview]
Message-ID: <871rt2jdgi.wl-kuninori.morimoto.gx@renesas.com> (raw)
In-Reply-To: <8736dijdit.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)
~~~~~^~~~
This patch fixup it
Signed-off-by: Karl Nasrallah <knnspeed@aol.com>
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
---
This is Karl's 1st pattern
arch/sh/include/asm/string_32.h | 54 ++++++++++++++++++++++++++---------------
1 file changed, 35 insertions(+), 19 deletions(-)
diff --git a/arch/sh/include/asm/string_32.h b/arch/sh/include/asm/string_32.h
index 3558b1d..d35b92f 100644
--- a/arch/sh/include/asm/string_32.h
+++ b/arch/sh/include/asm/string_32.h
@@ -31,27 +31,43 @@ 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;
+ register unsigned int * r0_register __asm__ ("r0");
+ /* 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_reg]\n\t"
+ "cmp/eq #0,%[r0_reg]\n\t"
+ "bt.s strncpy_pad\n\t"
+ "cmp/eq %[dest],%[dest_end]\n\t"
+ "bt.s strncpy_end\n\t"
+ "mov.b %[r0_reg],@%[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_reg],@%[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), [r0_reg] "+&z" (r0_register)
+ : [dest_end] "r" (__dest_end)
+ : "t","memory"
+ );
+
+ return retval;
}
#define __HAVE_ARCH_STRCMP
--
2.7.4
next prev parent reply other threads:[~2019-12-18 7:32 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-18 7:31 [PATCH 0/2] sh: use generic strncpy() Kuninori Morimoto
2019-12-18 7:32 ` Kuninori Morimoto [this message]
2019-12-18 7:35 ` [PATCH] " Kuninori Morimoto
2019-12-18 7:33 ` [PATCH] sh: fixup strncpy() Kuninori Morimoto
2020-05-31 9:43 ` John Paul Adrian Glaubitz
2020-05-31 23:43 ` Kuninori Morimoto
2020-06-01 8:15 ` John Paul Adrian Glaubitz
2020-06-07 12:34 ` John Paul Adrian Glaubitz
2020-06-08 0:57 ` Kuninori Morimoto
-- strict thread matches above, loose matches on Subject: below --
2019-12-18 5:22 [PATCH] sh: use generic strncpy() Kuninori Morimoto
2019-12-18 8:02 ` Geert Uytterhoeven
2019-12-19 0:45 ` Kuninori Morimoto
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