kernel-fxtec-pro1x/arch/arm64/include/asm/cpufeature.h
Will Deacon 905e8c5dca arm64: errata: add workaround for cortex-a53 erratum #845719
When running a compat (AArch32) userspace on Cortex-A53, a load at EL0
from a virtual address that matches the bottom 32 bits of the virtual
address used by a recent load at (AArch64) EL1 might return incorrect
data.

This patch works around the issue by writing to the contextidr_el1
register on the exception return path when returning to a 32-bit task.
This workaround is patched in at runtime based on the MIDR value of the
processor.

Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2015-04-01 10:24:31 +01:00

76 lines
1.9 KiB
C

/*
* Copyright (C) 2014 Linaro Ltd. <ard.biesheuvel@linaro.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#ifndef __ASM_CPUFEATURE_H
#define __ASM_CPUFEATURE_H
#include <asm/hwcap.h>
/*
* In the arm64 world (as in the ARM world), elf_hwcap is used both internally
* in the kernel and for user space to keep track of which optional features
* are supported by the current system. So let's map feature 'x' to HWCAP_x.
* Note that HWCAP_x constants are bit fields so we need to take the log.
*/
#define MAX_CPU_FEATURES (8 * sizeof(elf_hwcap))
#define cpu_feature(x) ilog2(HWCAP_ ## x)
#define ARM64_WORKAROUND_CLEAN_CACHE 0
#define ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE 1
#define ARM64_WORKAROUND_845719 2
#define ARM64_NCAPS 3
#ifndef __ASSEMBLY__
struct arm64_cpu_capabilities {
const char *desc;
u16 capability;
bool (*matches)(const struct arm64_cpu_capabilities *);
union {
struct { /* To be used for erratum handling only */
u32 midr_model;
u32 midr_range_min, midr_range_max;
};
};
};
extern DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS);
static inline bool cpu_have_feature(unsigned int num)
{
return elf_hwcap & (1UL << num);
}
static inline bool cpus_have_cap(unsigned int num)
{
if (num >= ARM64_NCAPS)
return false;
return test_bit(num, cpu_hwcaps);
}
static inline void cpus_set_cap(unsigned int num)
{
if (num >= ARM64_NCAPS)
pr_warn("Attempt to set an illegal CPU capability (%d >= %d)\n",
num, ARM64_NCAPS);
else
__set_bit(num, cpu_hwcaps);
}
void check_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
const char *info);
void check_local_cpu_errata(void);
void check_local_cpu_features(void);
bool cpu_supports_mixed_endian_el0(void);
bool system_supports_mixed_endian_el0(void);
#endif /* __ASSEMBLY__ */
#endif