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ARM: 7787/1: virt: ensure visibility of __boot_cpu_mode

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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>
Acked-by: Dave Martin <Dave.Martin@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Christoffer Dall <cdall@cs.columbia.edu>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Mark Rutland 2013-07-18 17:20:33 +01:00 committed by Russell King
parent ab8d46c060
commit 8fbac214e5
2 changed files with 14 additions and 0 deletions
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12
arch/arm/include/asm/virt.h
View File

@ -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

2
arch/arm/kernel/setup.c
View File

@ -836,6 +836,8 @@ 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");