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Commit 8fbac214 authored by Mark Rutland's avatar Mark Rutland Committed by Russell King
Browse files

ARM: 7787/1: 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: default avatarMark Rutland <mark.rutland@arm.com>
Acked-by: default avatarDave Martin <Dave.Martin@arm.com>
Acked-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Cc: Christoffer Dall <cdall@cs.columbia.edu>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent ab8d46c0

arch/arm/include/asm/virt.h

+12 −0
Original line number Original line Diff line number Diff line
@@ -29,6 +29,7 @@ 
#define BOOT_CPU_MODE_MISMATCH	PSR_N_BIT

#define BOOT_CPU_MODE_MISMATCH	PSR_N_BIT





#ifndef __ASSEMBLY__

#ifndef __ASSEMBLY__

#include <asm/cacheflush.h>





#ifdef CONFIG_ARM_VIRT_EXT

#ifdef CONFIG_ARM_VIRT_EXT

/*

/*
@@ -41,10 +42,21 @@ 
 */

 */

extern int __boot_cpu_mode;

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);

void __hyp_set_vectors(unsigned long phys_vector_base);

unsigned long __hyp_get_vectors(void);

unsigned long __hyp_get_vectors(void);

#else

#else

#define __boot_cpu_mode	(SVC_MODE)

#define __boot_cpu_mode	(SVC_MODE)

#define sync_boot_mode()

#endif

#endif





#ifndef ZIMAGE

#ifndef ZIMAGE

arch/arm/kernel/setup.c

+2 −0
Original line number Original line Diff line number Diff line
@@ -836,6 +836,8 @@ static int __init meminfo_cmp(const void *_a, const void *_b) 
void __init hyp_mode_check(void)

void __init hyp_mode_check(void)

{

{

#ifdef CONFIG_ARM_VIRT_EXT

#ifdef CONFIG_ARM_VIRT_EXT

	sync_boot_mode();



	if (is_hyp_mode_available()) {

	if (is_hyp_mode_available()) {

		pr_info("CPU: All CPU(s) started in HYP mode.\n");

		pr_info("CPU: All CPU(s) started in HYP mode.\n");

		pr_info("CPU: Virtualization extensions available.\n");

		pr_info("CPU: Virtualization extensions available.\n");