From: Dave.Martin@arm.com (Dave Martin)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/3] arm: virt: ensure visibility of __boot_cpu_mode
Date: Tue, 9 Jul 2013 17:32:18 +0100 [thread overview]
Message-ID: <20130709163217.GC2911@localhost.localdomain> (raw)
In-Reply-To: <1373379366-15689-3-git-send-email-mark.rutland@arm.com>
On Tue, Jul 09, 2013 at 03:16:05PM +0100, Mark Rutland wrote:
> 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 <mark.rutland@arm.com>
> Cc: Dave Martin <dave.martin@arm.com>
> Cc: Marc Zyngier <marc.zyngier@arm.com>
> Cc: Christoffer Dall <cdall@cs.columbia.edu>
Acked-by: Dave Martin <Dave.Martin@arm.com>
> ---
> 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 <asm/cacheflush.h>
>
> #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
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2013-07-09 16:32 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-09 14:16 [PATCH 0/3] arm/arm64: a trio of boot mode detection fixes Mark Rutland
2013-07-09 14:16 ` [PATCH 1/3] arm: hyp: fix macro parameterisation Mark Rutland
2013-07-09 16:29 ` Dave Martin
2013-07-09 14:16 ` [PATCH 2/3] arm: virt: ensure visibility of __boot_cpu_mode Mark Rutland
2013-07-09 16:32 ` Dave Martin [this message]
2013-07-09 14:16 ` [PATCH 3/3] arm64: " Mark Rutland
2013-07-18 15:26 ` [PATCH 0/3] arm/arm64: a trio of boot mode detection fixes Marc Zyngier
2013-07-18 16:25 ` Mark Rutland
2013-07-23 10:01 ` Catalin Marinas
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