From: Mark Rutland <mark.rutland@arm.com> To: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, Marco Elver <elver@google.com>, Catalin Marinas <catalin.marinas@arm.com>, Branislav Rankov <Branislav.Rankov@arm.com>, Alexander Potapenko <glider@google.com>, Evgenii Stepanov <eugenis@google.com>, Andrey Konovalov <andreyknvl@google.com>, Andrey Ryabinin <aryabinin@virtuozzo.com>, Will Deacon <will@kernel.org>, Dmitry Vyukov <dvyukov@google.com> Subject: Re: [PATCH v3 1/4] kasan, arm64: Add KASAN light mode Date: Fri, 15 Jan 2021 15:08:11 +0000 [thread overview] Message-ID: <20210115150811.GA44111@C02TD0UTHF1T.local> (raw) In-Reply-To: <20210115120043.50023-2-vincenzo.frascino@arm.com> On Fri, Jan 15, 2021 at 12:00:40PM +0000, Vincenzo Frascino wrote: > Architectures supported by KASAN HW can provide a light mode of > execution. On an MTE enabled arm64 hw for example this can be identified > with the asynch mode of execution. > In this mode, if a tag check fault occurs, the TFSR_EL1 register is > updated asynchronously. The kernel checks the corresponding bits > periodically. What's the expected usage of this relative to prod, given that this has to be chosen at boot time? When/where is this expected to be used relative to prod mode? > diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h > index 18fce223b67b..3a7c5beb7096 100644 > --- a/arch/arm64/include/asm/memory.h > +++ b/arch/arm64/include/asm/memory.h > @@ -231,7 +231,7 @@ static inline const void *__tag_set(const void *addr, u8 tag) > } > > #ifdef CONFIG_KASAN_HW_TAGS > -#define arch_enable_tagging() mte_enable_kernel() > +#define arch_enable_tagging(mode) mte_enable_kernel(mode) Rather than passing a mode in, I think it'd be better to have: * arch_enable_tagging_prod() * arch_enable_tagging_light() ... that we can map in the arch code to separate: * mte_enable_kernel_sync() * mte_enable_kernel_async() ... as by construction that avoids calls with an unhandled mode, and we wouldn't need the mode enum kasan_hw_tags_mode... > +static inline int hw_init_mode(enum kasan_arg_mode mode) > +{ > + switch (mode) { > + case KASAN_ARG_MODE_LIGHT: > + return KASAN_HW_TAGS_ASYNC; > + default: > + return KASAN_HW_TAGS_SYNC; > + } > +} ... and we can just have a wrapper like this to call either of the two functions directly, i.e. static inline void hw_enable_tagging_mode(enum kasan_arg_mode mode) { if (mode == KASAN_ARG_MODE_LIGHT) arch_enable_tagging_mode_light(); else arch_enable_tagging_mode_prod(); } Thanks, Mark.
WARNING: multiple messages have this Message-ID (diff)
From: Mark Rutland <mark.rutland@arm.com> To: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Marco Elver <elver@google.com>, Catalin Marinas <catalin.marinas@arm.com>, Branislav Rankov <Branislav.Rankov@arm.com>, kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org, Alexander Potapenko <glider@google.com>, Evgenii Stepanov <eugenis@google.com>, Andrey Konovalov <andreyknvl@google.com>, Dmitry Vyukov <dvyukov@google.com>, Andrey Ryabinin <aryabinin@virtuozzo.com>, Will Deacon <will@kernel.org>, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v3 1/4] kasan, arm64: Add KASAN light mode Date: Fri, 15 Jan 2021 15:08:11 +0000 [thread overview] Message-ID: <20210115150811.GA44111@C02TD0UTHF1T.local> (raw) In-Reply-To: <20210115120043.50023-2-vincenzo.frascino@arm.com> On Fri, Jan 15, 2021 at 12:00:40PM +0000, Vincenzo Frascino wrote: > Architectures supported by KASAN HW can provide a light mode of > execution. On an MTE enabled arm64 hw for example this can be identified > with the asynch mode of execution. > In this mode, if a tag check fault occurs, the TFSR_EL1 register is > updated asynchronously. The kernel checks the corresponding bits > periodically. What's the expected usage of this relative to prod, given that this has to be chosen at boot time? When/where is this expected to be used relative to prod mode? > diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h > index 18fce223b67b..3a7c5beb7096 100644 > --- a/arch/arm64/include/asm/memory.h > +++ b/arch/arm64/include/asm/memory.h > @@ -231,7 +231,7 @@ static inline const void *__tag_set(const void *addr, u8 tag) > } > > #ifdef CONFIG_KASAN_HW_TAGS > -#define arch_enable_tagging() mte_enable_kernel() > +#define arch_enable_tagging(mode) mte_enable_kernel(mode) Rather than passing a mode in, I think it'd be better to have: * arch_enable_tagging_prod() * arch_enable_tagging_light() ... that we can map in the arch code to separate: * mte_enable_kernel_sync() * mte_enable_kernel_async() ... as by construction that avoids calls with an unhandled mode, and we wouldn't need the mode enum kasan_hw_tags_mode... > +static inline int hw_init_mode(enum kasan_arg_mode mode) > +{ > + switch (mode) { > + case KASAN_ARG_MODE_LIGHT: > + return KASAN_HW_TAGS_ASYNC; > + default: > + return KASAN_HW_TAGS_SYNC; > + } > +} ... and we can just have a wrapper like this to call either of the two functions directly, i.e. static inline void hw_enable_tagging_mode(enum kasan_arg_mode mode) { if (mode == KASAN_ARG_MODE_LIGHT) arch_enable_tagging_mode_light(); else arch_enable_tagging_mode_prod(); } Thanks, Mark. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-01-15 15:09 UTC|newest] Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-01-15 12:00 [PATCH v3 0/4] arm64: ARMv8.5-A: MTE: Add async mode support Vincenzo Frascino 2021-01-15 12:00 ` Vincenzo Frascino 2021-01-15 12:00 ` [PATCH v3 1/4] kasan, arm64: Add KASAN light mode Vincenzo Frascino 2021-01-15 12:00 ` Vincenzo Frascino 2021-01-15 15:08 ` Mark Rutland [this message] 2021-01-15 15:08 ` Mark Rutland 2021-01-16 13:47 ` Vincenzo Frascino 2021-01-16 13:47 ` Vincenzo Frascino 2021-01-16 14:09 ` Andrey Konovalov 2021-01-16 14:09 ` Andrey Konovalov 2021-01-18 10:24 ` Mark Rutland 2021-01-18 10:24 ` Mark Rutland 2021-01-15 18:59 ` Andrey Konovalov 2021-01-15 18:59 ` Andrey Konovalov 2021-01-16 13:40 ` Vincenzo Frascino 2021-01-16 13:40 ` Vincenzo Frascino 2021-01-16 13:59 ` Andrey Konovalov 2021-01-16 13:59 ` Andrey Konovalov 2021-01-16 14:06 ` Vincenzo Frascino 2021-01-16 14:06 ` Vincenzo Frascino 2021-01-15 12:00 ` [PATCH v3 2/4] arm64: mte: Add asynchronous mode support Vincenzo Frascino 2021-01-15 12:00 ` Vincenzo Frascino 2021-01-15 15:13 ` Mark Rutland 2021-01-15 15:13 ` Mark Rutland 2021-01-16 13:49 ` Vincenzo Frascino 2021-01-16 13:49 ` Vincenzo Frascino 2021-01-15 12:00 ` [PATCH v3 3/4] arm64: mte: Enable async tag check fault Vincenzo Frascino 2021-01-15 12:00 ` Vincenzo Frascino 2021-01-15 15:37 ` Mark Rutland 2021-01-15 15:37 ` Mark Rutland 2021-01-18 12:57 ` Catalin Marinas 2021-01-18 12:57 ` Catalin Marinas 2021-01-18 13:37 ` Vincenzo Frascino 2021-01-18 13:37 ` Vincenzo Frascino 2021-01-18 14:14 ` Mark Rutland 2021-01-18 14:14 ` Mark Rutland 2021-01-18 14:48 ` Vincenzo Frascino 2021-01-18 14:48 ` Vincenzo Frascino 2021-01-18 15:39 ` Vincenzo Frascino 2021-01-18 15:39 ` Vincenzo Frascino 2021-01-18 15:40 ` Vincenzo Frascino 2021-01-18 15:40 ` Vincenzo Frascino 2021-01-15 12:00 ` [PATCH v3 4/4] arm64: mte: Optimize mte_assign_mem_tag_range() Vincenzo Frascino 2021-01-15 12:00 ` Vincenzo Frascino 2021-01-15 15:45 ` Mark Rutland 2021-01-15 15:45 ` Mark Rutland 2021-01-16 14:22 ` Vincenzo Frascino 2021-01-16 14:22 ` Vincenzo Frascino 2021-01-17 12:27 ` Vincenzo Frascino 2021-01-17 12:27 ` Vincenzo Frascino 2021-01-18 10:41 ` Mark Rutland 2021-01-18 10:41 ` Mark Rutland 2021-01-18 11:00 ` Vincenzo Frascino 2021-01-18 11:00 ` Vincenzo Frascino
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