Re: [PATCH v15 5/8] arm64: mte: Enable TCO in functions that can read beyond buffer limits
From: Catalin Marinas <catalin.marinas@arm.com>
Date: 2021-03-12 15:13:40
Also in:
lkml
On Fri, Mar 12, 2021 at 02:22:07PM +0000, Vincenzo Frascino wrote:
quoted hunk ↗ jump to hunk
diff --git a/arch/arm64/include/asm/mte.h b/arch/arm64/include/asm/mte.h index 9b557a457f24..8603c6636a7d 100644 --- a/arch/arm64/include/asm/mte.h +++ b/arch/arm64/include/asm/mte.h@@ -90,5 +90,20 @@ static inline void mte_assign_mem_tag_range(void *addr, size_t size) #endif /* CONFIG_ARM64_MTE */ +#ifdef CONFIG_KASAN_HW_TAGS +/* Whether the MTE asynchronous mode is enabled. */ +DECLARE_STATIC_KEY_FALSE(mte_async_mode); + +static inline bool system_uses_mte_async_mode(void) +{ + return static_branch_unlikely(&mte_async_mode); +} +#else +static inline bool system_uses_mte_async_mode(void) +{ + return false; +} +#endif /* CONFIG_KASAN_HW_TAGS */
You can write this with fewer lines:
DECLARE_STATIC_KEY_FALSE(mte_async_mode);
static inline bool system_uses_mte_async_mode(void)
{
return IS_ENABLED(CONFIG_KASAN_HW_TAGS) &&
static_branch_unlikely(&mte_async_mode);
}
The compiler will ensure that mte_async_mode is not referred when
!CONFIG_KASAN_HW_TAGS and therefore doesn't need to be defined.
quoted hunk ↗ jump to hunk
diff --git a/arch/arm64/kernel/mte.c b/arch/arm64/kernel/mte.c index fa755cf94e01..9362928ba0d5 100644 --- a/arch/arm64/kernel/mte.c +++ b/arch/arm64/kernel/mte.c@@ -26,6 +26,10 @@ u64 gcr_kernel_excl __ro_after_init; static bool report_fault_once = true; +/* Whether the MTE asynchronous mode is enabled. */ +DEFINE_STATIC_KEY_FALSE(mte_async_mode); +EXPORT_SYMBOL_GPL(mte_async_mode);
Maybe keep these bracketed by #ifdef CONFIG_KASAN_HW_TAGS. I think the mte_enable_kernel_*() aren't needed either if KASAN_HW is disabled (you can do it with an additional patch). With these, you can add: Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel