From: Matteo Croce <[email protected]>
When the destination buffer is before the source one, or when the
buffers doesn't overlap, it's safe to use memcpy() instead, which is
optimized to use a bigger data size possible.
Signed-off-by: Matteo Croce <[email protected]>
Reported-by: kernel test robot <[email protected]>
---
arch/riscv/include/asm/string.h | 6 ++--
arch/riscv/kernel/riscv_ksyms.c | 2 --
arch/riscv/lib/Makefile | 1 -
arch/riscv/lib/memmove.S | 64 ---------------------------------
arch/riscv/lib/string.c | 23 ++++++++++++
5 files changed, 26 insertions(+), 70 deletions(-)
delete mode 100644 arch/riscv/lib/memmove.S
diff --git a/arch/riscv/include/asm/string.h b/arch/riscv/include/asm/string.h
index 6b5d6fc3eab4..25d9b9078569 100644
--- a/arch/riscv/include/asm/string.h
+++ b/arch/riscv/include/asm/string.h
@@ -17,11 +17,11 @@ extern asmlinkage void *__memset(void *, int, size_t);
#define __HAVE_ARCH_MEMCPY
extern void *memcpy(void *dest, const void *src, size_t count);
extern void *__memcpy(void *dest, const void *src, size_t count);
+#define __HAVE_ARCH_MEMMOVE
+extern void *memmove(void *dest, const void *src, size_t count);
+extern void *__memmove(void *dest, const void *src, size_t count);
#endif
-#define __HAVE_ARCH_MEMMOVE
-extern asmlinkage void *memmove(void *, const void *, size_t);
-extern asmlinkage void *__memmove(void *, const void *, size_t);
/* For those files which don't want to check by kasan. */
#if defined(CONFIG_KASAN) && !defined(__SANITIZE_ADDRESS__)
#define memcpy(dst, src, len) __memcpy(dst, src, len)
diff --git a/arch/riscv/kernel/riscv_ksyms.c b/arch/riscv/kernel/riscv_ksyms.c
index 3f6d512a5b97..361565c4db7e 100644
--- a/arch/riscv/kernel/riscv_ksyms.c
+++ b/arch/riscv/kernel/riscv_ksyms.c
@@ -10,6 +10,4 @@
* Assembly functions that may be used (directly or indirectly) by modules
*/
EXPORT_SYMBOL(memset);
-EXPORT_SYMBOL(memmove);
EXPORT_SYMBOL(__memset);
-EXPORT_SYMBOL(__memmove);
diff --git a/arch/riscv/lib/Makefile b/arch/riscv/lib/Makefile
index 2ffe85d4baee..484f5ff7b508 100644
--- a/arch/riscv/lib/Makefile
+++ b/arch/riscv/lib/Makefile
@@ -1,7 +1,6 @@
# SPDX-License-Identifier: GPL-2.0-only
lib-y += delay.o
lib-y += memset.o
-lib-y += memmove.o
lib-$(CONFIG_MMU) += uaccess.o
lib-$(CONFIG_64BIT) += tishift.o
lib-$(CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE) += string.o
diff --git a/arch/riscv/lib/memmove.S b/arch/riscv/lib/memmove.S
deleted file mode 100644
index 07d1d2152ba5..000000000000
--- a/arch/riscv/lib/memmove.S
+++ /dev/null
@@ -1,64 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-
-#include <linux/linkage.h>
-#include <asm/asm.h>
-
-ENTRY(__memmove)
-WEAK(memmove)
- move t0, a0
- move t1, a1
-
- beq a0, a1, exit_memcpy
- beqz a2, exit_memcpy
- srli t2, a2, 0x2
-
- slt t3, a0, a1
- beqz t3, do_reverse
-
- andi a2, a2, 0x3
- li t4, 1
- beqz t2, byte_copy
-
-word_copy:
- lw t3, 0(a1)
- addi t2, t2, -1
- addi a1, a1, 4
- sw t3, 0(a0)
- addi a0, a0, 4
- bnez t2, word_copy
- beqz a2, exit_memcpy
- j byte_copy
-
-do_reverse:
- add a0, a0, a2
- add a1, a1, a2
- andi a2, a2, 0x3
- li t4, -1
- beqz t2, reverse_byte_copy
-
-reverse_word_copy:
- addi a1, a1, -4
- addi t2, t2, -1
- lw t3, 0(a1)
- addi a0, a0, -4
- sw t3, 0(a0)
- bnez t2, reverse_word_copy
- beqz a2, exit_memcpy
-
-reverse_byte_copy:
- addi a0, a0, -1
- addi a1, a1, -1
-
-byte_copy:
- lb t3, 0(a1)
- addi a2, a2, -1
- sb t3, 0(a0)
- add a1, a1, t4
- add a0, a0, t4
- bnez a2, byte_copy
-
-exit_memcpy:
- move a0, t0
- move a1, t1
- ret
-END(__memmove)
diff --git a/arch/riscv/lib/string.c b/arch/riscv/lib/string.c
index bfc912ee23f8..da033af8fe2f 100644
--- a/arch/riscv/lib/string.c
+++ b/arch/riscv/lib/string.c
@@ -88,3 +88,26 @@ EXPORT_SYMBOL(__memcpy);
void *memcpy(void *dest, const void *src, size_t count) __weak __alias(__memcpy);
EXPORT_SYMBOL(memcpy);
+
+/*
+ * Simply check if the buffer overlaps an call memcpy() in case,
+ * otherwise do a simple one byte at time backward copy.
+ */
+void *__memmove(void *dest, const void *src, size_t count)
+{
+ if (dest < src || src + count <= dest)
+ return memcpy(dest, src, count);
+
+ if (dest > src) {
+ const char *s = src + count;
+ char *tmp = dest + count;
+
+ while (count--)
+ *--tmp = *--s;
+ }
+ return dest;
+}
+EXPORT_SYMBOL(__memmove);
+
+void *memmove(void *dest, const void *src, size_t count) __weak __alias(__memmove);
+EXPORT_SYMBOL(memmove);
--
2.31.1
Hi Matteo,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on linux/master]
[also build test ERROR on linus/master v5.15-rc1 next-20210917]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Matteo-Croce/riscv-optimized-mem-functions/20210920-032303
base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git bdb575f872175ed0ecf2638369da1cb7a6e86a14
config: riscv-randconfig-r004-20210919 (attached as .config)
compiler: riscv64-linux-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/0day-ci/linux/commit/9a948fd7d78a58890608e9dd0f77e5ff84f36e3e
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Matteo-Croce/riscv-optimized-mem-functions/20210920-032303
git checkout 9a948fd7d78a58890608e9dd0f77e5ff84f36e3e
# save the attached .config to linux build tree
mkdir build_dir
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=riscv SHELL=/bin/bash
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>
All errors (new ones prefixed by >>):
arch/riscv/lib/string.c: In function '__memmove':
>> arch/riscv/lib/string.c:89:7: error: inlining failed in call to 'always_inline' 'memcpy': function body can be overwritten at link time
89 | void *memcpy(void *dest, const void *src, size_t count) __weak __alias(__memcpy);
| ^~~~~~
arch/riscv/lib/string.c:99:24: note: called from here
99 | return memcpy(dest, src, count);
| ^~~~~~~~~~~~~~~~~~~~~~~~
vim +89 arch/riscv/lib/string.c
86c5866e9b7fdd Matteo Croce 2021-09-19 88
86c5866e9b7fdd Matteo Croce 2021-09-19 @89 void *memcpy(void *dest, const void *src, size_t count) __weak __alias(__memcpy);
86c5866e9b7fdd Matteo Croce 2021-09-19 90 EXPORT_SYMBOL(memcpy);
9a948fd7d78a58 Matteo Croce 2021-09-19 91
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[email protected]
On Mon, Sep 20, 2021 at 12:06 AM kernel test robot <[email protected]> wrote:
>
> Hi Matteo,
>
> Thank you for the patch! Yet something to improve:
>
> [auto build test ERROR on linux/master]
> [also build test ERROR on linus/master v5.15-rc1 next-20210917]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch]
>
> url: https://github.com/0day-ci/linux/commits/Matteo-Croce/riscv-optimized-mem-functions/20210920-032303
> base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git bdb575f872175ed0ecf2638369da1cb7a6e86a14
> config: riscv-randconfig-r004-20210919 (attached as .config)
> compiler: riscv64-linux-gcc (GCC) 11.2.0
> reproduce (this is a W=1 build):
> wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> chmod +x ~/bin/make.cross
> # https://github.com/0day-ci/linux/commit/9a948fd7d78a58890608e9dd0f77e5ff84f36e3e
> git remote add linux-review https://github.com/0day-ci/linux
> git fetch --no-tags linux-review Matteo-Croce/riscv-optimized-mem-functions/20210920-032303
> git checkout 9a948fd7d78a58890608e9dd0f77e5ff84f36e3e
> # save the attached .config to linux build tree
> mkdir build_dir
> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=riscv SHELL=/bin/bash
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <[email protected]>
>
> All errors (new ones prefixed by >>):
>
> arch/riscv/lib/string.c: In function '__memmove':
> >> arch/riscv/lib/string.c:89:7: error: inlining failed in call to 'always_inline' 'memcpy': function body can be overwritten at link time
> 89 | void *memcpy(void *dest, const void *src, size_t count) __weak __alias(__memcpy);
> | ^~~~~~
> arch/riscv/lib/string.c:99:24: note: called from here
> 99 | return memcpy(dest, src, count);
> | ^~~~~~~~~~~~~~~~~~~~~~~~
>
>
> vim +89 arch/riscv/lib/string.c
>
> 86c5866e9b7fdd Matteo Croce 2021-09-19 88
> 86c5866e9b7fdd Matteo Croce 2021-09-19 @89 void *memcpy(void *dest, const void *src, size_t count) __weak __alias(__memcpy);
> 86c5866e9b7fdd Matteo Croce 2021-09-19 90 EXPORT_SYMBOL(memcpy);
> 9a948fd7d78a58 Matteo Croce 2021-09-19 91
>
> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/[email protected]
How can we fix this? Maybe calling __memcpy() instead?
--
per aspera ad upstream
On Mon, 27 Sept 2021 at 12:49, Matteo Croce <[email protected]> wrote:
>
> On Mon, Sep 20, 2021 at 12:06 AM kernel test robot <[email protected]> wrote:
> >
> > Hi Matteo,
> >
> > Thank you for the patch! Yet something to improve:
> >
> > [auto build test ERROR on linux/master]
> > [also build test ERROR on linus/master v5.15-rc1 next-20210917]
> > [If your patch is applied to the wrong git tree, kindly drop us a note.
> > And when submitting patch, we suggest to use '--base' as documented in
> > https://git-scm.com/docs/git-format-patch]
> >
> > url: https://github.com/0day-ci/linux/commits/Matteo-Croce/riscv-optimized-mem-functions/20210920-032303
> > base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git bdb575f872175ed0ecf2638369da1cb7a6e86a14
> > config: riscv-randconfig-r004-20210919 (attached as .config)
> > compiler: riscv64-linux-gcc (GCC) 11.2.0
> > reproduce (this is a W=1 build):
> > wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> > chmod +x ~/bin/make.cross
> > # https://github.com/0day-ci/linux/commit/9a948fd7d78a58890608e9dd0f77e5ff84f36e3e
> > git remote add linux-review https://github.com/0day-ci/linux
> > git fetch --no-tags linux-review Matteo-Croce/riscv-optimized-mem-functions/20210920-032303
> > git checkout 9a948fd7d78a58890608e9dd0f77e5ff84f36e3e
> > # save the attached .config to linux build tree
> > mkdir build_dir
> > COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=riscv SHELL=/bin/bash
> >
> > If you fix the issue, kindly add following tag as appropriate
> > Reported-by: kernel test robot <[email protected]>
> >
> > All errors (new ones prefixed by >>):
> >
> > arch/riscv/lib/string.c: In function '__memmove':
> > >> arch/riscv/lib/string.c:89:7: error: inlining failed in call to 'always_inline' 'memcpy': function body can be overwritten at link time
> > 89 | void *memcpy(void *dest, const void *src, size_t count) __weak __alias(__memcpy);
> > | ^~~~~~
> > arch/riscv/lib/string.c:99:24: note: called from here
> > 99 | return memcpy(dest, src, count);
> > | ^~~~~~~~~~~~~~~~~~~~~~~~
> >
> >
> > vim +89 arch/riscv/lib/string.c
> >
> > 86c5866e9b7fdd Matteo Croce 2021-09-19 88
> > 86c5866e9b7fdd Matteo Croce 2021-09-19 @89 void *memcpy(void *dest, const void *src, size_t count) __weak __alias(__memcpy);
> > 86c5866e9b7fdd Matteo Croce 2021-09-19 90 EXPORT_SYMBOL(memcpy);
> > 9a948fd7d78a58 Matteo Croce 2021-09-19 91
> >
> > ---
> > 0-DAY CI Kernel Test Service, Intel Corporation
> > https://lists.01.org/hyperkitty/list/[email protected]
>
> How can we fix this? Maybe calling __memcpy() instead?
Yes, that fixes building with CONFIG_FORTIFY_SOURCE=y for me. Kasan
already wraps memmove itself, so it should be fine to call __memcpy
directly.
/Emil