From: Vineet Gupta <Vineet.Gupta1@synopsys.com> To: Arnd Bergmann <arnd@arndb.de> Cc: Khalid Aziz <khalid.aziz@oracle.com>, Andrey Konovalov <andreyknvl@google.com>, Andrew Morton <akpm@linux-foundation.org>, "Peter Zijlstra" <peterz@infradead.org>, Christian Brauner <christian.brauner@ubuntu.com>, Kees Cook <keescook@chromium.org>, "Ingo Molnar" <mingo@kernel.org>, Aleksa Sarai <cyphar@cyphar.com>, Linus Torvalds <torvalds@linux-foundation.org>, "open list:SYNOPSYS ARC ARCHITECTURE" <linux-snps-arc@lists.infradead.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, linux-arch <linux-arch@vger.kernel.org> Subject: Re: [RFC 4/4] ARC: uaccess: use optimized generic __strnlen_user/__strncpy_from_user Date: Tue, 14 Jan 2020 21:36:15 +0000 [thread overview] Message-ID: <3734021d-1756-3a09-6595-14ca58c64bf9@synopsys.com> (raw) In-Reply-To: <CAK8P3a2GUqmcA_q33=20OrK1+cU4f3mCrgci_bO3ho4B5PRODg@mail.gmail.com> On 1/14/20 12:42 PM, Arnd Bergmann wrote: > On Tue, Jan 14, 2020 at 9:08 PM Vineet Gupta <Vineet.Gupta1@synopsys.com> wrote: > >> diff --git a/arch/arc/include/asm/word-at-a-time.h b/arch/arc/include/asm/word-at-a-time.h >> new file mode 100644 >> index 000000000000..00e92be70987 >> --- /dev/null >> +++ b/arch/arc/include/asm/word-at-a-time.h >> @@ -0,0 +1,49 @@ >> +/* SPDX-License-Identifier: GPL-2.0-only */ >> +/* >> + * Copyright (C) 2020 Synopsys Inc. >> + */ >> +#ifndef __ASM_ARC_WORD_AT_A_TIME_H >> +#define __ASM_ARC_WORD_AT_A_TIME_H >> + >> +#ifdef __LITTLE_ENDIAN__ >> + >> +#include <linux/kernel.h> >> + >> +struct word_at_a_time { >> + const unsigned long one_bits, high_bits; >> +}; > > What's wrong with the generic version on little-endian? Any > chance you can find a way to make it work as well for you as > this copy? find_zero() by default doesn't use pop count instructions. I didn't like the copy either but wasn't sure of the best way to make this 4 API interface reusable. Are you suggesting we allow partial over-ride starting with #ifndef find_zero ? >> +static inline unsigned long find_zero(unsigned long mask) >> +{ >> +#ifdef CONFIG_64BIT >> + return fls64(mask) >> 3; >> +#else >> + return fls(mask) >> 3; >> +#endif > > The CONFIG_64BIT check not be needed, unless you are adding > support for 64-bit ARC really soon. :-) Indeed that was the premise ! Thx for the quick review. -Vineet
WARNING: multiple messages have this Message-ID (diff)
From: Vineet Gupta <Vineet.Gupta1@synopsys.com> To: Arnd Bergmann <arnd@arndb.de> Cc: linux-arch <linux-arch@vger.kernel.org>, Kees Cook <keescook@chromium.org>, Peter Zijlstra <peterz@infradead.org>, Andrey Konovalov <andreyknvl@google.com>, Aleksa Sarai <cyphar@cyphar.com>, Ingo Molnar <mingo@kernel.org>, Khalid Aziz <khalid.aziz@oracle.com>, Andrew Morton <akpm@linux-foundation.org>, "open list:SYNOPSYS ARC ARCHITECTURE" <linux-snps-arc@lists.infradead.org>, Linus Torvalds <torvalds@linux-foundation.org>, Christian Brauner <christian.brauner@ubuntu.com>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org> Subject: Re: [RFC 4/4] ARC: uaccess: use optimized generic __strnlen_user/__strncpy_from_user Date: Tue, 14 Jan 2020 21:36:15 +0000 [thread overview] Message-ID: <3734021d-1756-3a09-6595-14ca58c64bf9@synopsys.com> (raw) In-Reply-To: <CAK8P3a2GUqmcA_q33=20OrK1+cU4f3mCrgci_bO3ho4B5PRODg@mail.gmail.com> On 1/14/20 12:42 PM, Arnd Bergmann wrote: > On Tue, Jan 14, 2020 at 9:08 PM Vineet Gupta <Vineet.Gupta1@synopsys.com> wrote: > >> diff --git a/arch/arc/include/asm/word-at-a-time.h b/arch/arc/include/asm/word-at-a-time.h >> new file mode 100644 >> index 000000000000..00e92be70987 >> --- /dev/null >> +++ b/arch/arc/include/asm/word-at-a-time.h >> @@ -0,0 +1,49 @@ >> +/* SPDX-License-Identifier: GPL-2.0-only */ >> +/* >> + * Copyright (C) 2020 Synopsys Inc. >> + */ >> +#ifndef __ASM_ARC_WORD_AT_A_TIME_H >> +#define __ASM_ARC_WORD_AT_A_TIME_H >> + >> +#ifdef __LITTLE_ENDIAN__ >> + >> +#include <linux/kernel.h> >> + >> +struct word_at_a_time { >> + const unsigned long one_bits, high_bits; >> +}; > > What's wrong with the generic version on little-endian? Any > chance you can find a way to make it work as well for you as > this copy? find_zero() by default doesn't use pop count instructions. I didn't like the copy either but wasn't sure of the best way to make this 4 API interface reusable. Are you suggesting we allow partial over-ride starting with #ifndef find_zero ? >> +static inline unsigned long find_zero(unsigned long mask) >> +{ >> +#ifdef CONFIG_64BIT >> + return fls64(mask) >> 3; >> +#else >> + return fls(mask) >> 3; >> +#endif > > The CONFIG_64BIT check not be needed, unless you are adding > support for 64-bit ARC really soon. :-) Indeed that was the premise ! Thx for the quick review. -Vineet _______________________________________________ linux-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc
next prev parent reply other threads:[~2020-01-14 21:37 UTC|newest] Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-01-14 20:08 [RFC 0/4] Switching ARC to optimized generic strncpy_from_user Vineet Gupta 2020-01-14 20:08 ` Vineet Gupta 2020-01-14 20:08 ` Vineet Gupta 2020-01-14 20:08 ` [RFC 1/4] asm-generic/uaccess: don't define inline functions if noinline lib/* in use Vineet Gupta 2020-01-14 20:08 ` Vineet Gupta 2020-01-14 20:57 ` Arnd Bergmann 2020-01-14 20:57 ` Arnd Bergmann 2020-01-14 20:57 ` Arnd Bergmann 2020-01-15 23:01 ` Vineet Gupta 2020-01-15 23:01 ` Vineet Gupta 2020-01-15 23:01 ` Vineet Gupta 2020-01-16 11:43 ` Arnd Bergmann 2020-01-16 11:43 ` Arnd Bergmann 2020-01-16 11:43 ` Arnd Bergmann 2020-01-14 21:32 ` Linus Torvalds 2020-01-14 21:32 ` Linus Torvalds 2020-01-15 9:08 ` Arnd Bergmann 2020-01-15 9:08 ` Arnd Bergmann 2020-01-15 9:08 ` Arnd Bergmann 2020-01-15 14:12 ` Al Viro 2020-01-15 14:12 ` Al Viro 2020-01-15 14:12 ` Al Viro 2020-01-15 14:21 ` Arnd Bergmann 2020-01-15 14:21 ` Arnd Bergmann 2020-01-15 14:21 ` Arnd Bergmann 2020-01-14 20:08 ` [RFC 2/4] lib/strncpy_from_user: Remove redundant user space pointer range check Vineet Gupta 2020-01-14 20:08 ` Vineet Gupta 2020-01-14 21:22 ` Linus Torvalds 2020-01-14 21:22 ` Linus Torvalds 2020-01-14 21:52 ` Vineet Gupta 2020-01-14 21:52 ` Vineet Gupta 2020-01-14 21:52 ` Vineet Gupta 2020-01-14 23:46 ` Al Viro 2020-01-14 23:46 ` Al Viro 2020-01-15 14:42 ` Andrey Konovalov 2020-01-15 14:42 ` Andrey Konovalov 2020-01-15 14:42 ` Andrey Konovalov 2020-01-15 23:00 ` Vineet Gupta 2020-01-15 23:00 ` Vineet Gupta 2020-01-15 23:00 ` Vineet Gupta 2020-01-14 20:08 ` [RFC 3/4] ARC: uaccess: remove noinline variants of __strncpy_from_user() and friends Vineet Gupta 2020-01-14 20:08 ` Vineet Gupta 2020-01-14 20:08 ` [RFC 4/4] ARC: uaccess: use optimized generic __strnlen_user/__strncpy_from_user Vineet Gupta 2020-01-14 20:08 ` Vineet Gupta 2020-01-14 20:42 ` Arnd Bergmann 2020-01-14 20:42 ` Arnd Bergmann 2020-01-14 20:42 ` Arnd Bergmann 2020-01-14 21:36 ` Vineet Gupta [this message] 2020-01-14 21:36 ` Vineet Gupta 2020-01-14 21:36 ` Vineet Gupta 2020-01-14 21:49 ` Linus Torvalds 2020-01-14 21:49 ` Linus Torvalds 2020-01-14 21:49 ` Linus Torvalds 2020-01-14 22:14 ` Vineet Gupta 2020-01-14 22:14 ` Vineet Gupta 2020-01-14 22:14 ` Vineet Gupta
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