63 lines
1.3 KiB
C
63 lines
1.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_X86_PKRU_H
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#define _ASM_X86_PKRU_H
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#include <asm/cpufeature.h>
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#define PKRU_AD_BIT 0x1u
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#define PKRU_WD_BIT 0x2u
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#define PKRU_BITS_PER_PKEY 2
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#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
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extern u32 init_pkru_value;
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#define pkru_get_init_value() READ_ONCE(init_pkru_value)
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#else
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#define init_pkru_value 0
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#define pkru_get_init_value() 0
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#endif
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static inline bool __pkru_allows_read(u32 pkru, u16 pkey)
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{
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int pkru_pkey_bits = pkey * PKRU_BITS_PER_PKEY;
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return !(pkru & (PKRU_AD_BIT << pkru_pkey_bits));
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}
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static inline bool __pkru_allows_write(u32 pkru, u16 pkey)
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{
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int pkru_pkey_bits = pkey * PKRU_BITS_PER_PKEY;
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/*
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* Access-disable disables writes too so we need to check
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* both bits here.
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*/
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return !(pkru & ((PKRU_AD_BIT|PKRU_WD_BIT) << pkru_pkey_bits));
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}
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static inline u32 read_pkru(void)
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{
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if (cpu_feature_enabled(X86_FEATURE_OSPKE))
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return rdpkru();
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return 0;
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}
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static inline void write_pkru(u32 pkru)
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{
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if (!cpu_feature_enabled(X86_FEATURE_OSPKE))
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return;
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/*
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* WRPKRU is relatively expensive compared to RDPKRU.
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* Avoid WRPKRU when it would not change the value.
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*/
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if (pkru != rdpkru())
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wrpkru(pkru);
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}
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static inline void pkru_write_default(void)
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{
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if (!cpu_feature_enabled(X86_FEATURE_OSPKE))
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return;
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wrpkru(pkru_get_init_value());
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}
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#endif
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