From: Marek Szyprowski <m.szyprowski@samsung.com> To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: Marek Szyprowski <m.szyprowski@samsung.com>, Russell King <rmk+kernel@armlinux.org.uk>, Arnd Bergmann <arnd@arndb.de>, Mark Rutland <mark.rutland@arm.com>, Andre Przywara <andre.przywara@arm.com>, Will Deacon <will.deacon@arm.com>, Catalin Marinas <catalin.marinas@arm.com>, linux-samsung-soc@vger.kernel.org, Krzysztof Kozlowski <krzk@kernel.org>, Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>, Seung-Woo Kim <sw0312.kim@samsung.com> Subject: [PATCH] ARM: Add workaround for I-Cache line size mismatch between CPU cores Date: Tue, 28 May 2019 10:28:46 +0200 [thread overview] Message-ID: <20190528082846.21625-1-m.szyprowski@samsung.com> (raw) In-Reply-To: CGME20190528082903eucas1p1ef54fa6aee420bffa11be61d5efb4c46@eucas1p1.samsung.com Some big.LITTLE systems have I-Cache line size mismatch between LITTLE and big cores. This patch adds a workaround for proper I-Cache support on such systems. Without it, some class of the userspace code (typically self-modifying) might suffer from random SIGILL failures. Similar workaround already exists for ARM64 architecture. I has been added by commit 116c81f427ff ("arm64: Work around systems with mismatched cache line sizes"). Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> --- This workaround is needed on all supported Exynos big.LITTLE SoCs: 5420, 5422 and 5800. Resend reason: removed RFC tag as there are no comments, I will upload this patch to the patch tracking system --- arch/arm/configs/exynos_defconfig | 1 + arch/arm/include/asm/cacheflush.h | 7 +++++++ arch/arm/kernel/smp.c | 1 + arch/arm/mm/Kconfig | 8 ++++++++ arch/arm/mm/cache-v7.S | 13 +++++++++++++ arch/arm/mm/init.c | 16 ++++++++++++++++ arch/arm/mm/mm.h | 2 ++ 7 files changed, 48 insertions(+) diff --git a/arch/arm/configs/exynos_defconfig b/arch/arm/configs/exynos_defconfig index c95c54284da2..9b959afaaa12 100644 --- a/arch/arm/configs/exynos_defconfig +++ b/arch/arm/configs/exynos_defconfig @@ -9,6 +9,7 @@ CONFIG_MODULE_UNLOAD=y CONFIG_PARTITION_ADVANCED=y CONFIG_ARCH_EXYNOS=y CONFIG_ARCH_EXYNOS3=y +CONFIG_CPU_ICACHE_MISMATCH_WORKAROUND=y CONFIG_SMP=y CONFIG_BIG_LITTLE=y CONFIG_NR_CPUS=8 diff --git a/arch/arm/include/asm/cacheflush.h b/arch/arm/include/asm/cacheflush.h index ec1a5fd0d294..ec4fd2e2dd60 100644 --- a/arch/arm/include/asm/cacheflush.h +++ b/arch/arm/include/asm/cacheflush.h @@ -479,4 +479,11 @@ static inline void __sync_cache_range_r(volatile void *p, size_t size) void flush_uprobe_xol_access(struct page *page, unsigned long uaddr, void *kaddr, unsigned long len); + +#ifdef CONFIG_CPU_ICACHE_MISMATCH_WORKAROUND +void check_cpu_icache_size(int cpuid); +#else +static inline void check_cpu_icache_size(int cpuid) { } +#endif + #endif diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index 8687d619260f..261be0e5bc03 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -373,6 +373,7 @@ static void smp_store_cpu_info(unsigned int cpuid) cpu_info->cpuid = read_cpuid_id(); store_cpu_topology(cpuid); + check_cpu_icache_size(cpuid); } /* diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig index b169e580bf82..d4733e086f2b 100644 --- a/arch/arm/mm/Kconfig +++ b/arch/arm/mm/Kconfig @@ -780,6 +780,14 @@ config CPU_ICACHE_DISABLE Say Y here to disable the processor instruction cache. Unless you have a reason not to or are unsure, say N. +config CPU_ICACHE_MISMATCH_WORKAROUND + bool "Workaround for I-Cache line size mismatch between CPU cores" + depends on SMP && CPU_V7 + help + Some big.LITTLE systems have I-Cache line size mismatch between + LITTLE and big cores. Say Y here to enable a workaround for + proper I-Cache support on such systems. If unsure, say N. + config CPU_DCACHE_DISABLE bool "Disable D-Cache (C-bit)" depends on (CPU_CP15 && !SMP) || CPU_V7M diff --git a/arch/arm/mm/cache-v7.S b/arch/arm/mm/cache-v7.S index 2149b47a0c5a..db3986708c8a 100644 --- a/arch/arm/mm/cache-v7.S +++ b/arch/arm/mm/cache-v7.S @@ -19,6 +19,14 @@ #include "proc-macros.S" +#ifdef CONFIG_CPU_ICACHE_MISMATCH_WORKAROUND +.globl icache_size + .data + .align 2 +icache_size: + .long 64 + .text +#endif /* * The secondary kernel init calls v7_flush_dcache_all before it enables * the L1; however, the L1 comes out of reset in an undefined state, so @@ -284,7 +292,12 @@ ENTRY(v7_coherent_user_range) cmp r12, r1 blo 1b dsb ishst +#ifdef CONFIG_CPU_ICACHE_MISMATCH_WORKAROUND + ldr r3, =icache_size + ldr r2, [r3, #0] +#else icache_line_size r2, r3 +#endif sub r3, r2, #1 bic r12, r0, r3 2: diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c index be0b42937888..1a66af5bd259 100644 --- a/arch/arm/mm/init.c +++ b/arch/arm/mm/init.c @@ -242,6 +242,22 @@ static void __init arm_initrd_init(void) #endif } +#ifdef CONFIG_CPU_ICACHE_MISMATCH_WORKAROUND +void check_cpu_icache_size(int cpuid) +{ + u32 size, ctr; + + asm("mrc p15, 0, %0, c0, c0, 1" : "=r" (ctr)); + + size = 1 << ((ctr & 0xf) + 2); + if (cpuid != 0 && icache_size != size) + pr_info("CPU%u: detected I-Cache line size mismatch, workaround enabled\n", + cpuid); + if (icache_size > size) + icache_size = size; +} +#endif + void __init arm_memblock_init(const struct machine_desc *mdesc) { /* Register the kernel text, kernel data and initrd with memblock. */ diff --git a/arch/arm/mm/mm.h b/arch/arm/mm/mm.h index 6b045c6653ea..941356d95a67 100644 --- a/arch/arm/mm/mm.h +++ b/arch/arm/mm/mm.h @@ -8,6 +8,8 @@ /* the upper-most page table pointer */ extern pmd_t *top_pmd; +extern int icache_size; + /* * 0xffff8000 to 0xffffffff is reserved for any ARM architecture * specific hacks for copying pages efficiently, while 0xffff4000 -- 2.17.1
WARNING: multiple messages have this Message-ID (diff)
From: Marek Szyprowski <m.szyprowski@samsung.com> To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: Mark Rutland <mark.rutland@arm.com>, linux-samsung-soc@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>, Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>, Andre Przywara <andre.przywara@arm.com>, Will Deacon <will.deacon@arm.com>, Krzysztof Kozlowski <krzk@kernel.org>, Seung-Woo Kim <sw0312.kim@samsung.com>, Russell King <rmk+kernel@armlinux.org.uk>, Catalin Marinas <catalin.marinas@arm.com>, Marek Szyprowski <m.szyprowski@samsung.com> Subject: [PATCH] ARM: Add workaround for I-Cache line size mismatch between CPU cores Date: Tue, 28 May 2019 10:28:46 +0200 [thread overview] Message-ID: <20190528082846.21625-1-m.szyprowski@samsung.com> (raw) In-Reply-To: CGME20190528082903eucas1p1ef54fa6aee420bffa11be61d5efb4c46@eucas1p1.samsung.com Some big.LITTLE systems have I-Cache line size mismatch between LITTLE and big cores. This patch adds a workaround for proper I-Cache support on such systems. Without it, some class of the userspace code (typically self-modifying) might suffer from random SIGILL failures. Similar workaround already exists for ARM64 architecture. I has been added by commit 116c81f427ff ("arm64: Work around systems with mismatched cache line sizes"). Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> --- This workaround is needed on all supported Exynos big.LITTLE SoCs: 5420, 5422 and 5800. Resend reason: removed RFC tag as there are no comments, I will upload this patch to the patch tracking system --- arch/arm/configs/exynos_defconfig | 1 + arch/arm/include/asm/cacheflush.h | 7 +++++++ arch/arm/kernel/smp.c | 1 + arch/arm/mm/Kconfig | 8 ++++++++ arch/arm/mm/cache-v7.S | 13 +++++++++++++ arch/arm/mm/init.c | 16 ++++++++++++++++ arch/arm/mm/mm.h | 2 ++ 7 files changed, 48 insertions(+) diff --git a/arch/arm/configs/exynos_defconfig b/arch/arm/configs/exynos_defconfig index c95c54284da2..9b959afaaa12 100644 --- a/arch/arm/configs/exynos_defconfig +++ b/arch/arm/configs/exynos_defconfig @@ -9,6 +9,7 @@ CONFIG_MODULE_UNLOAD=y CONFIG_PARTITION_ADVANCED=y CONFIG_ARCH_EXYNOS=y CONFIG_ARCH_EXYNOS3=y +CONFIG_CPU_ICACHE_MISMATCH_WORKAROUND=y CONFIG_SMP=y CONFIG_BIG_LITTLE=y CONFIG_NR_CPUS=8 diff --git a/arch/arm/include/asm/cacheflush.h b/arch/arm/include/asm/cacheflush.h index ec1a5fd0d294..ec4fd2e2dd60 100644 --- a/arch/arm/include/asm/cacheflush.h +++ b/arch/arm/include/asm/cacheflush.h @@ -479,4 +479,11 @@ static inline void __sync_cache_range_r(volatile void *p, size_t size) void flush_uprobe_xol_access(struct page *page, unsigned long uaddr, void *kaddr, unsigned long len); + +#ifdef CONFIG_CPU_ICACHE_MISMATCH_WORKAROUND +void check_cpu_icache_size(int cpuid); +#else +static inline void check_cpu_icache_size(int cpuid) { } +#endif + #endif diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index 8687d619260f..261be0e5bc03 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -373,6 +373,7 @@ static void smp_store_cpu_info(unsigned int cpuid) cpu_info->cpuid = read_cpuid_id(); store_cpu_topology(cpuid); + check_cpu_icache_size(cpuid); } /* diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig index b169e580bf82..d4733e086f2b 100644 --- a/arch/arm/mm/Kconfig +++ b/arch/arm/mm/Kconfig @@ -780,6 +780,14 @@ config CPU_ICACHE_DISABLE Say Y here to disable the processor instruction cache. Unless you have a reason not to or are unsure, say N. +config CPU_ICACHE_MISMATCH_WORKAROUND + bool "Workaround for I-Cache line size mismatch between CPU cores" + depends on SMP && CPU_V7 + help + Some big.LITTLE systems have I-Cache line size mismatch between + LITTLE and big cores. Say Y here to enable a workaround for + proper I-Cache support on such systems. If unsure, say N. + config CPU_DCACHE_DISABLE bool "Disable D-Cache (C-bit)" depends on (CPU_CP15 && !SMP) || CPU_V7M diff --git a/arch/arm/mm/cache-v7.S b/arch/arm/mm/cache-v7.S index 2149b47a0c5a..db3986708c8a 100644 --- a/arch/arm/mm/cache-v7.S +++ b/arch/arm/mm/cache-v7.S @@ -19,6 +19,14 @@ #include "proc-macros.S" +#ifdef CONFIG_CPU_ICACHE_MISMATCH_WORKAROUND +.globl icache_size + .data + .align 2 +icache_size: + .long 64 + .text +#endif /* * The secondary kernel init calls v7_flush_dcache_all before it enables * the L1; however, the L1 comes out of reset in an undefined state, so @@ -284,7 +292,12 @@ ENTRY(v7_coherent_user_range) cmp r12, r1 blo 1b dsb ishst +#ifdef CONFIG_CPU_ICACHE_MISMATCH_WORKAROUND + ldr r3, =icache_size + ldr r2, [r3, #0] +#else icache_line_size r2, r3 +#endif sub r3, r2, #1 bic r12, r0, r3 2: diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c index be0b42937888..1a66af5bd259 100644 --- a/arch/arm/mm/init.c +++ b/arch/arm/mm/init.c @@ -242,6 +242,22 @@ static void __init arm_initrd_init(void) #endif } +#ifdef CONFIG_CPU_ICACHE_MISMATCH_WORKAROUND +void check_cpu_icache_size(int cpuid) +{ + u32 size, ctr; + + asm("mrc p15, 0, %0, c0, c0, 1" : "=r" (ctr)); + + size = 1 << ((ctr & 0xf) + 2); + if (cpuid != 0 && icache_size != size) + pr_info("CPU%u: detected I-Cache line size mismatch, workaround enabled\n", + cpuid); + if (icache_size > size) + icache_size = size; +} +#endif + void __init arm_memblock_init(const struct machine_desc *mdesc) { /* Register the kernel text, kernel data and initrd with memblock. */ diff --git a/arch/arm/mm/mm.h b/arch/arm/mm/mm.h index 6b045c6653ea..941356d95a67 100644 --- a/arch/arm/mm/mm.h +++ b/arch/arm/mm/mm.h @@ -8,6 +8,8 @@ /* the upper-most page table pointer */ extern pmd_t *top_pmd; +extern int icache_size; + /* * 0xffff8000 to 0xffffffff is reserved for any ARM architecture * specific hacks for copying pages efficiently, while 0xffff4000 -- 2.17.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next parent reply other threads:[~2019-05-28 8:29 UTC|newest] Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <CGME20190528082903eucas1p1ef54fa6aee420bffa11be61d5efb4c46@eucas1p1.samsung.com> 2019-05-28 8:28 ` Marek Szyprowski [this message] 2019-05-28 8:28 ` [PATCH] ARM: Add workaround for I-Cache line size mismatch between CPU cores Marek Szyprowski 2019-05-29 8:41 ` Krzysztof Kozlowski 2019-05-29 8:41 ` Krzysztof Kozlowski 2019-05-29 8:41 ` Krzysztof Kozlowski
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