905e8c5dca
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>
76 lines
1.9 KiB
C
76 lines
1.9 KiB
C
/*
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* Copyright (C) 2014 Linaro Ltd. <ard.biesheuvel@linaro.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#ifndef __ASM_CPUFEATURE_H
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#define __ASM_CPUFEATURE_H
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#include <asm/hwcap.h>
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/*
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* In the arm64 world (as in the ARM world), elf_hwcap is used both internally
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* in the kernel and for user space to keep track of which optional features
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* are supported by the current system. So let's map feature 'x' to HWCAP_x.
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* Note that HWCAP_x constants are bit fields so we need to take the log.
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*/
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#define MAX_CPU_FEATURES (8 * sizeof(elf_hwcap))
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#define cpu_feature(x) ilog2(HWCAP_ ## x)
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#define ARM64_WORKAROUND_CLEAN_CACHE 0
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#define ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE 1
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#define ARM64_WORKAROUND_845719 2
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#define ARM64_NCAPS 3
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#ifndef __ASSEMBLY__
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struct arm64_cpu_capabilities {
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const char *desc;
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u16 capability;
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bool (*matches)(const struct arm64_cpu_capabilities *);
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union {
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struct { /* To be used for erratum handling only */
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u32 midr_model;
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u32 midr_range_min, midr_range_max;
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};
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};
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};
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extern DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS);
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static inline bool cpu_have_feature(unsigned int num)
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{
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return elf_hwcap & (1UL << num);
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}
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static inline bool cpus_have_cap(unsigned int num)
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{
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if (num >= ARM64_NCAPS)
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return false;
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return test_bit(num, cpu_hwcaps);
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}
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static inline void cpus_set_cap(unsigned int num)
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{
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if (num >= ARM64_NCAPS)
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pr_warn("Attempt to set an illegal CPU capability (%d >= %d)\n",
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num, ARM64_NCAPS);
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else
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__set_bit(num, cpu_hwcaps);
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}
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void check_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
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const char *info);
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void check_local_cpu_errata(void);
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void check_local_cpu_features(void);
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bool cpu_supports_mixed_endian_el0(void);
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bool system_supports_mixed_endian_el0(void);
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#endif /* __ASSEMBLY__ */
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#endif
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