From mboxrd@z Thu Jan 1 00:00:00 1970 From: mark.rutland@arm.com (Mark Rutland) Date: Tue, 9 Jul 2013 15:16:05 +0100 Subject: [PATCH 2/3] arm: virt: ensure visibility of __boot_cpu_mode In-Reply-To: <1373379366-15689-1-git-send-email-mark.rutland@arm.com> References: <1373379366-15689-1-git-send-email-mark.rutland@arm.com> Message-ID: <1373379366-15689-3-git-send-email-mark.rutland@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Secondary CPUs write to __boot_cpu_mode with caches disabled, and thus a cached value of __boot_cpu_mode may be incoherent with that in memory. This could lead to a failure to detect mismatched boot modes. This patch adds flushing to ensure that writes by secondaries to __boot_cpu_mode are made visible before we test against it. Signed-off-by: Mark Rutland Cc: Dave Martin Cc: Marc Zyngier Cc: Christoffer Dall --- arch/arm/include/asm/virt.h | 12 ++++++++++++ arch/arm/kernel/setup.c | 2 ++ 2 files changed, 14 insertions(+) diff --git a/arch/arm/include/asm/virt.h b/arch/arm/include/asm/virt.h index 50af92b..4371f45 100644 --- a/arch/arm/include/asm/virt.h +++ b/arch/arm/include/asm/virt.h @@ -29,6 +29,7 @@ #define BOOT_CPU_MODE_MISMATCH PSR_N_BIT #ifndef __ASSEMBLY__ +#include #ifdef CONFIG_ARM_VIRT_EXT /* @@ -41,10 +42,21 @@ */ extern int __boot_cpu_mode; +static inline void sync_boot_mode(void) +{ + /* + * As secondaries write to __boot_cpu_mode with caches disabled, we + * must flush the corresponding cache entries to ensure the visibility + * of their writes. + */ + sync_cache_r(&__boot_cpu_mode); +} + void __hyp_set_vectors(unsigned long phys_vector_base); unsigned long __hyp_get_vectors(void); #else #define __boot_cpu_mode (SVC_MODE) +#define sync_boot_mode() #endif #ifndef ZIMAGE diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c index b4b1d39..4af9b38 100644 --- a/arch/arm/kernel/setup.c +++ b/arch/arm/kernel/setup.c @@ -744,6 +744,8 @@ static int __init meminfo_cmp(const void *_a, const void *_b) void __init hyp_mode_check(void) { #ifdef CONFIG_ARM_VIRT_EXT + sync_boot_mode(); + if (is_hyp_mode_available()) { pr_info("CPU: All CPU(s) started in HYP mode.\n"); pr_info("CPU: Virtualization extensions available.\n"); -- 1.8.1.1