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arm64: virt: ensure visibility of __boot_cpu_mode 

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: Marc Zyngier <marc.zyngier@arm.com>
Cc: Christoffer Dall <cdall@cs.columbia.edu>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Mark Rutland 2013-07-09 15:16:06 +01:00 committed by Catalin Marinas
parent 3b2f64d00c
commit 82b2f495fb
1 changed files with 13 additions and 0 deletions
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13
arch/arm64/include/asm/virt.h
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@ -21,6 +21,7 @@
#define BOOT_CPU_MODE_EL2 (0x0e12b007)
#ifndef __ASSEMBLY__
#include <asm/cacheflush.h>
/*
* __boot_cpu_mode records what mode CPUs were booted in.
@ -36,9 +37,20 @@ extern u32 __boot_cpu_mode[2];
void __hyp_set_vectors(phys_addr_t phys_vector_base);
phys_addr_t __hyp_get_vectors(void);
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.
*/
__flush_dcache_area(__boot_cpu_mode, sizeof(__boot_cpu_mode));
}
/* Reports the availability of HYP mode */
static inline bool is_hyp_mode_available(void)
{
sync_boot_mode();
return (__boot_cpu_mode[0] == BOOT_CPU_MODE_EL2 &&
__boot_cpu_mode[1] == BOOT_CPU_MODE_EL2);
}
@ -46,6 +58,7 @@ static inline bool is_hyp_mode_available(void)
/* Check if the bootloader has booted CPUs in different modes */
static inline bool is_hyp_mode_mismatched(void)
{
sync_boot_mode();
return __boot_cpu_mode[0] != __boot_cpu_mode[1];
}