From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- arch/x86/include/asm/pkru.h | 62 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 62 insertions(+) create mode 100644 arch/x86/include/asm/pkru.h (limited to 'arch/x86/include/asm/pkru.h') diff --git a/arch/x86/include/asm/pkru.h b/arch/x86/include/asm/pkru.h new file mode 100644 index 000000000..74f0a2d34 --- /dev/null +++ b/arch/x86/include/asm/pkru.h @@ -0,0 +1,62 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_X86_PKRU_H +#define _ASM_X86_PKRU_H + +#include + +#define PKRU_AD_BIT 0x1u +#define PKRU_WD_BIT 0x2u +#define PKRU_BITS_PER_PKEY 2 + +#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS +extern u32 init_pkru_value; +#define pkru_get_init_value() READ_ONCE(init_pkru_value) +#else +#define init_pkru_value 0 +#define pkru_get_init_value() 0 +#endif + +static inline bool __pkru_allows_read(u32 pkru, u16 pkey) +{ + int pkru_pkey_bits = pkey * PKRU_BITS_PER_PKEY; + return !(pkru & (PKRU_AD_BIT << pkru_pkey_bits)); +} + +static inline bool __pkru_allows_write(u32 pkru, u16 pkey) +{ + int pkru_pkey_bits = pkey * PKRU_BITS_PER_PKEY; + /* + * Access-disable disables writes too so we need to check + * both bits here. + */ + return !(pkru & ((PKRU_AD_BIT|PKRU_WD_BIT) << pkru_pkey_bits)); +} + +static inline u32 read_pkru(void) +{ + if (cpu_feature_enabled(X86_FEATURE_OSPKE)) + return rdpkru(); + return 0; +} + +static inline void write_pkru(u32 pkru) +{ + if (!cpu_feature_enabled(X86_FEATURE_OSPKE)) + return; + /* + * WRPKRU is relatively expensive compared to RDPKRU. + * Avoid WRPKRU when it would not change the value. + */ + if (pkru != rdpkru()) + wrpkru(pkru); +} + +static inline void pkru_write_default(void) +{ + if (!cpu_feature_enabled(X86_FEATURE_OSPKE)) + return; + + wrpkru(pkru_get_init_value()); +} + +#endif -- cgit v1.2.3