From: Ira Weiny <ira.weiny@xxxxxxxxx> Protection Keys for Supervisor pages (PKS) enables fast, hardware thread specific, manipulation of permission restrictions on supervisor page mappings. It uses the same mechanism of Protection Keys as those on User mappings but applies that mechanism to supervisor mappings using a supervisor specific MSR. Kernel users can define domains of page mappings which have an extra level of protection beyond those specified in the supervisor page table entries. Define the PKS CPU feature bits. Add the Kconfig ARCH_HAS_SUPERVISOR_PKEYS to indicate to consumers that an architecture supports pkeys. Introduce ARCH_ENABLE_SUPERVISOR_PKEYS to allow kernel users to specify to the arch that they wish to use the supervisor key support if ARCH_HAS_SUPERVISOR_PKEYS is available. ARCH_ENABLE_SUPERVISOR_PKEYS remains off until the first use case sets it. Reviewed-by: Dan Williams <dan.j.williams@xxxxxxxxx> Co-developed-by: Fenghua Yu <fenghua.yu@xxxxxxxxx> Signed-off-by: Fenghua Yu <fenghua.yu@xxxxxxxxx> Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx> --- Changes from V3: From Dan Clean up commit message Add ARCH_ENABLE_SUPERVISOR_PKEYS option there is no overhead of PKS unless there is a user Clean up commit message grammar Changes from V2 New patch for V3: Split this off from the enable patch to be able to create cleaner bisectability --- arch/x86/Kconfig | 1 + arch/x86/include/asm/cpufeatures.h | 1 + arch/x86/include/asm/disabled-features.h | 8 +++++++- arch/x86/include/uapi/asm/processor-flags.h | 2 ++ mm/Kconfig | 4 ++++ 5 files changed, 15 insertions(+), 1 deletion(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 2792879d398e..5e3a7c2bc342 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1870,6 +1870,7 @@ config X86_INTEL_MEMORY_PROTECTION_KEYS depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) select ARCH_USES_HIGH_VMA_FLAGS select ARCH_HAS_PKEYS + select ARCH_HAS_SUPERVISOR_PKEYS help Memory Protection Keys provides a mechanism for enforcing page-based protections, but without requiring modification of the diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h index cc96e26d69f7..83ed73407417 100644 --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -359,6 +359,7 @@ #define X86_FEATURE_MOVDIR64B (16*32+28) /* MOVDIR64B instruction */ #define X86_FEATURE_ENQCMD (16*32+29) /* ENQCMD and ENQCMDS instructions */ #define X86_FEATURE_SGX_LC (16*32+30) /* Software Guard Extensions Launch Control */ +#define X86_FEATURE_PKS (16*32+31) /* Protection Keys for Supervisor pages */ /* AMD-defined CPU features, CPUID level 0x80000007 (EBX), word 17 */ #define X86_FEATURE_OVERFLOW_RECOV (17*32+ 0) /* MCA overflow recovery support */ diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h index b7dd944dc867..fd09ae852c04 100644 --- a/arch/x86/include/asm/disabled-features.h +++ b/arch/x86/include/asm/disabled-features.h @@ -44,6 +44,12 @@ # define DISABLE_OSPKE (1<<(X86_FEATURE_OSPKE & 31)) #endif /* CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS */ +#ifdef CONFIG_ARCH_ENABLE_SUPERVISOR_PKEYS +# define DISABLE_PKS 0 +#else +# define DISABLE_PKS (1<<(X86_FEATURE_PKS & 31)) +#endif + #ifdef CONFIG_X86_5LEVEL # define DISABLE_LA57 0 #else @@ -88,7 +94,7 @@ #define DISABLED_MASK14 0 #define DISABLED_MASK15 0 #define DISABLED_MASK16 (DISABLE_PKU|DISABLE_OSPKE|DISABLE_LA57|DISABLE_UMIP| \ - DISABLE_ENQCMD) + DISABLE_ENQCMD|DISABLE_PKS) #define DISABLED_MASK17 0 #define DISABLED_MASK18 0 #define DISABLED_MASK19 0 diff --git a/arch/x86/include/uapi/asm/processor-flags.h b/arch/x86/include/uapi/asm/processor-flags.h index bcba3c643e63..191c574b2390 100644 --- a/arch/x86/include/uapi/asm/processor-flags.h +++ b/arch/x86/include/uapi/asm/processor-flags.h @@ -130,6 +130,8 @@ #define X86_CR4_SMAP _BITUL(X86_CR4_SMAP_BIT) #define X86_CR4_PKE_BIT 22 /* enable Protection Keys support */ #define X86_CR4_PKE _BITUL(X86_CR4_PKE_BIT) +#define X86_CR4_PKS_BIT 24 /* enable Protection Keys for Supervisor */ +#define X86_CR4_PKS _BITUL(X86_CR4_PKS_BIT) /* * x86-64 Task Priority Register, CR8 diff --git a/mm/Kconfig b/mm/Kconfig index 24c045b24b95..c7d1fc780358 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -808,6 +808,10 @@ config ARCH_USES_HIGH_VMA_FLAGS bool config ARCH_HAS_PKEYS bool +config ARCH_HAS_SUPERVISOR_PKEYS + bool +config ARCH_ENABLE_SUPERVISOR_PKEYS + bool config PERCPU_STATS bool "Collect percpu memory statistics" -- 2.28.0.rc0.12.gb6a658bd00c9
