Re: [PATCH v3 9/9] asm-generic: reverse GENERIC_{STRNCPY_FROM,STRNLEN}_USER symbols
On 7/22/21 2:48 PM, Arnd Bergmann wrote:
From: Arnd Bergmann
Most architectures do not need a custom implementation, and in most
cases the generic implementation is preferred, so change the polariy
on these Kconfig symbols to require architectures to select them when
they provide their own version.
The new name is CONFIG_ARCH_HAS_{STRNCPY_FROM,STRNLEN}_USER.
The remaining architectures at the moment are: ia64, mips, parisc,
s390, um and xtensa. We should probably convert these as well, but
I was not sure how far to take this series.
Acked-by: Helge Deller # parisc
Thanks!
Helge
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Re: [PATCH v3 9/9] asm-generic: reverse GENERIC_{STRNCPY_FROM, STRNLEN}_USER symbols
On Thu, Jul 22, 2021 at 2:50 PM Arnd Bergmann wrote:
> From: Arnd Bergmann
>
> Most architectures do not need a custom implementation, and in most
> cases the generic implementation is preferred, so change the polariy
> on these Kconfig symbols to require architectures to select them when
> they provide their own version.
>
> The new name is CONFIG_ARCH_HAS_{STRNCPY_FROM,STRNLEN}_USER.
>
> The remaining architectures at the moment are: ia64, mips, parisc,
> s390, um and xtensa. We should probably convert these as well, but
> I was not sure how far to take this series.
>
> Cc: "James E.J. Bottomley"
> Cc: Anton Ivanov
> Cc: Christian Borntraeger
> Cc: Heiko Carstens
> Cc: Helge Deller
> Cc: Jeff Dike
> Cc: Max Filippov
> Cc: Richard Weinberger
> Cc: Thomas Bogendoerfer
> Cc: Vasily Gorbik
> Cc: linux-i...@vger.kernel.org
> Cc: linux-m...@vger.kernel.org
> Cc: linux-par...@vger.kernel.org
> Cc: linux-s...@vger.kernel.org
> Cc: linux...@lists.infradead.org
> Cc: linux-xte...@linux-xtensa.org
> Signed-off-by: Arnd Bergmann
> arch/m68k/Kconfig | 2 --
Acked-by: Geert Uytterhoeven
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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Re: [PATCH v3 9/9] asm-generic: reverse GENERIC_{STRNCPY_FROM, STRNLEN}_USER symbols
On Thu, Jul 22, 2021 at 10:07 PM Heiko Carstens wrote: > > Feel free to add the s390 patch below on top of your series. Thanks a lot, added now. > However one question: the strncpy_from_user() prototype now comes everywhere > without the __must_check attribute. Is there any reason for that? > > At least for s390 I want to keep that. Makes sense, I'll add a patch for that as well. Arnd ___ linux-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc
Re: [PATCH v3 9/9] asm-generic: reverse GENERIC_{STRNCPY_FROM, STRNLEN}_USER symbols
On Thu, Jul 22, 2021 at 04:01:39PM +0200, Arnd Bergmann wrote:
> On Thu, Jul 22, 2021 at 3:57 PM Johannes Berg
> wrote:
> >
> > >
> > > The remaining architectures at the moment are: ia64, mips, parisc,
> > > s390, um and xtensa. We should probably convert these as well, but
> >
> > I'm not sure it makes sense to convert um, the implementation uses
> > strncpy(), and that should use the libc implementation, which is tuned
> > for the actual hardware that the binary is running on, so performance
> > wise that might be better.
> >
> > OTOH, maybe this is all in the noise given the huge syscall overhead in
> > um, so maybe unifying it would make more sense.
>
> Right, makes sense. I suppose if we end up converting mips and s390,
> we should just do arch/um and the others as well for consistency, even
> if that adds some overhead.
Feel free to add the s390 patch below on top of your series. However
one question: the strncpy_from_user() prototype now comes everywhere
without the __must_check attribute. Is there any reason for that?
At least for s390 I want to keep that.
>From 03ad679909af58e1dc6864f47ce67210f0534c39 Mon Sep 17 00:00:00 2001
From: Heiko Carstens
Date: Thu, 22 Jul 2021 21:48:18 +0200
Subject: [PATCH] s390: use generic strncpy/strnlen from_user
The s390 variant of strncpy_from_user() is slightly faster than the
generic variant, however convert to the generic variant now to follow
most if not all other architectures.
Converting to the generic variant was already considered a couple of
years ago. See commit f5c8b9601036 ("s390/uaccess: use sane length for
__strncpy_from_user()").
Signed-off-by: Heiko Carstens
---
arch/s390/Kconfig | 2 --
arch/s390/include/asm/uaccess.h | 18 ++--
arch/s390/lib/uaccess.c | 52 -
3 files changed, 2 insertions(+), 70 deletions(-)
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index f4f39087cad0..a0e2130f0100 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -75,8 +75,6 @@ config S390
select ARCH_HAS_SET_MEMORY
select ARCH_HAS_STRICT_KERNEL_RWX
select ARCH_HAS_STRICT_MODULE_RWX
- select ARCH_HAS_STRNCPY_FROM_USER
- select ARCH_HAS_STRNLEN_USER
select ARCH_HAS_SYSCALL_WRAPPER
select ARCH_HAS_UBSAN_SANITIZE_ALL
select ARCH_HAS_VDSO_DATA
diff --git a/arch/s390/include/asm/uaccess.h b/arch/s390/include/asm/uaccess.h
index 2316f2440881..9ed9aa37e836 100644
--- a/arch/s390/include/asm/uaccess.h
+++ b/arch/s390/include/asm/uaccess.h
@@ -233,23 +233,9 @@ raw_copy_in_user(void __user *to, const void __user *from,
unsigned long n);
/*
* Copy a null terminated string from userspace.
*/
+long __must_check strncpy_from_user(char *dst, const char __user *src, long
count);
-long __strncpy_from_user(char *dst, const char __user *src, long count);
-
-static inline long __must_check
-strncpy_from_user(char *dst, const char __user *src, long count)
-{
- might_fault();
- return __strncpy_from_user(dst, src, count);
-}
-
-unsigned long __must_check __strnlen_user(const char __user *src, unsigned
long count);
-
-static inline unsigned long strnlen_user(const char __user *src, unsigned long
n)
-{
- might_fault();
- return __strnlen_user(src, n);
-}
+long __must_check strnlen_user(const char __user *src, long count);
/*
* Zero Userspace
diff --git a/arch/s390/lib/uaccess.c b/arch/s390/lib/uaccess.c
index 7ec8b1fa0f08..94ca99bde59d 100644
--- a/arch/s390/lib/uaccess.c
+++ b/arch/s390/lib/uaccess.c
@@ -338,55 +338,3 @@ unsigned long __clear_user(void __user *to, unsigned long
size)
return clear_user_xc(to, size);
}
EXPORT_SYMBOL(__clear_user);
-
-static inline unsigned long strnlen_user_srst(const char __user *src,
- unsigned long size)
-{
- unsigned long tmp1, tmp2;
-
- asm volatile(
- " lghi 0,0\n"
- " la%2,0(%1)\n"
- " la%3,0(%0,%1)\n"
- " slgr %0,%0\n"
- " sacf 256\n"
- "0: srst %3,%2\n"
- " jo0b\n"
- " la%0,1(%3)\n" /* strnlen_user results includes \0 */
- " slgr %0,%1\n"
- "1: sacf 768\n"
- EX_TABLE(0b,1b)
- : "+a" (size), "+a" (src), "=a" (tmp1), "=a" (tmp2)
- :
- : "cc", "memory", "0");
- return size;
-}
-
-unsigned long __strnlen_user(const char __user *src, unsigned long size)
-{
- if (unlikely(!size))
- return 0;
- return strnlen_user_srst(src, size);
-}
-EXPORT_SYMBOL(__strnlen_user);
-
-long __strncpy_from_user(char *dst, const char __user *src, long size)
-{
- size_t done, len, offset, len_str;
-
- if (unlikely(size <= 0))
- return 0;
- done = 0;
- do {
- offset = (size_t)src & (L1_CACHE_BYTES - 1);
-
Re: [PATCH v3 9/9] asm-generic: reverse GENERIC_{STRNCPY_FROM, STRNLEN}_USER symbols
On Thu, Jul 22, 2021 at 3:57 PM Johannes Berg wrote: > > > > > The remaining architectures at the moment are: ia64, mips, parisc, > > s390, um and xtensa. We should probably convert these as well, but > > I'm not sure it makes sense to convert um, the implementation uses > strncpy(), and that should use the libc implementation, which is tuned > for the actual hardware that the binary is running on, so performance > wise that might be better. > > OTOH, maybe this is all in the noise given the huge syscall overhead in > um, so maybe unifying it would make more sense. Right, makes sense. I suppose if we end up converting mips and s390, we should just do arch/um and the others as well for consistency, even if that adds some overhead. Arnd ___ linux-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc
Re: [PATCH v3 9/9] asm-generic: reverse GENERIC_{STRNCPY_FROM, STRNLEN}_USER symbols
> > The remaining architectures at the moment are: ia64, mips, parisc, > s390, um and xtensa. We should probably convert these as well, but I'm not sure it makes sense to convert um, the implementation uses strncpy(), and that should use the libc implementation, which is tuned for the actual hardware that the binary is running on, so performance wise that might be better. OTOH, maybe this is all in the noise given the huge syscall overhead in um, so maybe unifying it would make more sense. johannes ___ linux-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc
Re: [PATCH v3 9/9] asm-generic: reverse GENERIC_{STRNCPY_FROM,STRNLEN}_USER symbols
On Thu, Jul 22, 2021 at 02:48:14PM +0200, Arnd Bergmann wrote:
> From: Arnd Bergmann
>
> Most architectures do not need a custom implementation, and in most
> cases the generic implementation is preferred, so change the polariy
> on these Kconfig symbols to require architectures to select them when
> they provide their own version.
>
> The new name is CONFIG_ARCH_HAS_{STRNCPY_FROM,STRNLEN}_USER.
>
> The remaining architectures at the moment are: ia64, mips, parisc,
> s390, um and xtensa. We should probably convert these as well, but
> I was not sure how far to take this series.
Looks good,
Reviewed-by: Christoph Hellwig
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