User-Mode Instruction Prevention is a security feature present in new Intel processors that, when set, prevents the execution of a subset of instructions if such instructions are executed in user mode (CPL > 0). Attempting to execute such instructions causes a general protection exception.
The subset of instructions comprises: * SGDT - Store Global Descriptor Table * SIDT - Store Interrupt Descriptor Table * SLDT - Store Local Descriptor Table * SMSW - Store Machine Status Word * STR - Store Task Register This feature is also added to the list of disabled-features to allow a cleaner handling of build-time configuration. Cc: Andy Lutomirski <l...@kernel.org> Cc: Andrew Morton <a...@linux-foundation.org> Cc: H. Peter Anvin <h...@zytor.com> Cc: Borislav Petkov <b...@suse.de> Cc: Brian Gerst <brge...@gmail.com> Cc: Chen Yucong <sla...@gmail.com> Cc: Chris Metcalf <cmetc...@mellanox.com> Cc: Dave Hansen <dave.han...@linux.intel.com> Cc: Fenghua Yu <fenghua...@intel.com> Cc: Huang Rui <ray.hu...@amd.com> Cc: Jiri Slaby <jsl...@suse.cz> Cc: Jonathan Corbet <cor...@lwn.net> Cc: Michael S. Tsirkin <m...@redhat.com> Cc: Paul Gortmaker <paul.gortma...@windriver.com> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Ravi V. Shankar <ravi.v.shan...@intel.com> Cc: Shuah Khan <sh...@kernel.org> Cc: Vlastimil Babka <vba...@suse.cz> Cc: Tony Luck <tony.l...@intel.com> Cc: Paolo Bonzini <pbonz...@redhat.com> Cc: x...@kernel.org Reviewed-by: Borislav Petkov <b...@suse.de> Signed-off-by: Ricardo Neri <ricardo.neri-calde...@linux.intel.com> --- arch/x86/include/asm/cpufeatures.h | 1 + arch/x86/include/asm/disabled-features.h | 8 +++++++- arch/x86/include/uapi/asm/processor-flags.h | 2 ++ 3 files changed, 10 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h index 2519c6c..d1f18f2 100644 --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -292,6 +292,7 @@ /* Intel-defined CPU features, CPUID level 0x00000007:0 (ecx), word 16 */ #define X86_FEATURE_AVX512VBMI (16*32+ 1) /* AVX512 Vector Bit Manipulation instructions*/ +#define X86_FEATURE_UMIP (16*32+ 2) /* User Mode Instruction Protection */ #define X86_FEATURE_PKU (16*32+ 3) /* Protection Keys for Userspace */ #define X86_FEATURE_OSPKE (16*32+ 4) /* OS Protection Keys Enable */ #define X86_FEATURE_AVX512_VPOPCNTDQ (16*32+14) /* POPCNT for vectors of DW/QW */ diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h index c10c912..14d6d50 100644 --- a/arch/x86/include/asm/disabled-features.h +++ b/arch/x86/include/asm/disabled-features.h @@ -16,6 +16,12 @@ # define DISABLE_MPX (1<<(X86_FEATURE_MPX & 31)) #endif +#ifdef CONFIG_X86_INTEL_UMIP +# define DISABLE_UMIP 0 +#else +# define DISABLE_UMIP (1<<(X86_FEATURE_UMIP & 31)) +#endif + #ifdef CONFIG_X86_64 # define DISABLE_VME (1<<(X86_FEATURE_VME & 31)) # define DISABLE_K6_MTRR (1<<(X86_FEATURE_K6_MTRR & 31)) @@ -63,7 +69,7 @@ #define DISABLED_MASK13 0 #define DISABLED_MASK14 0 #define DISABLED_MASK15 0 -#define DISABLED_MASK16 (DISABLE_PKU|DISABLE_OSPKE|DISABLE_LA57) +#define DISABLED_MASK16 (DISABLE_PKU|DISABLE_OSPKE|DISABLE_LA57|DISABLE_UMIP) #define DISABLED_MASK17 0 #define DISABLED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 18) diff --git a/arch/x86/include/uapi/asm/processor-flags.h b/arch/x86/include/uapi/asm/processor-flags.h index 39946d0..cf4c876 100644 --- a/arch/x86/include/uapi/asm/processor-flags.h +++ b/arch/x86/include/uapi/asm/processor-flags.h @@ -104,6 +104,8 @@ #define X86_CR4_OSFXSR _BITUL(X86_CR4_OSFXSR_BIT) #define X86_CR4_OSXMMEXCPT_BIT 10 /* enable unmasked SSE exceptions */ #define X86_CR4_OSXMMEXCPT _BITUL(X86_CR4_OSXMMEXCPT_BIT) +#define X86_CR4_UMIP_BIT 11 /* enable UMIP support */ +#define X86_CR4_UMIP _BITUL(X86_CR4_UMIP_BIT) #define X86_CR4_LA57_BIT 12 /* enable 5-level page tables */ #define X86_CR4_LA57 _BITUL(X86_CR4_LA57_BIT) #define X86_CR4_VMXE_BIT 13 /* enable VMX virtualization */ -- 2.7.4
