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linux-next/arch/arm/include/asm/virt.h
Mark Rutland 8fbac214e5 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: 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>
2013-07-26 12:01:17 +01:00

82 lines
2.4 KiB
C

/*
* Copyright (c) 2012 Linaro Limited.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifndef VIRT_H
#define VIRT_H
#include <asm/ptrace.h>
/*
* Flag indicating that the kernel was not entered in the same mode on every
* CPU. The zImage loader stashes this value in an SPSR, so we need an
* architecturally defined flag bit here.
*/
#define BOOT_CPU_MODE_MISMATCH PSR_N_BIT
#ifndef __ASSEMBLY__
#include <asm/cacheflush.h>
#ifdef CONFIG_ARM_VIRT_EXT
/*
* __boot_cpu_mode records what mode the primary CPU was booted in.
* A correctly-implemented bootloader must start all CPUs in the same mode:
* if it fails to do this, the flag BOOT_CPU_MODE_MISMATCH is set to indicate
* that some CPU(s) were booted in a different mode.
*
* This allows the kernel to flag an error when the secondaries have come up.
*/
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
void hyp_mode_check(void);
/* Reports the availability of HYP mode */
static inline bool is_hyp_mode_available(void)
{
return ((__boot_cpu_mode & MODE_MASK) == HYP_MODE &&
!(__boot_cpu_mode & BOOT_CPU_MODE_MISMATCH));
}
/* Check if the bootloader has booted CPUs in different modes */
static inline bool is_hyp_mode_mismatched(void)
{
return !!(__boot_cpu_mode & BOOT_CPU_MODE_MISMATCH);
}
#endif
#endif /* __ASSEMBLY__ */
#endif /* ! VIRT_H */