[RFC 3/9] x86: CPUID and CR3/CR4 flags for Linear Address Masking
From: Kirill A. Shutemov
Date: Fri Feb 05 2021 - 15:20:57 EST
Enumerate Linear Address Masking and provide defines for CR3 and CR4
flags.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
arch/x86/include/asm/cpufeatures.h | 1 +
arch/x86/include/uapi/asm/processor-flags.h | 6 ++++++
2 files changed, 7 insertions(+)
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index dad350d42ecf..3ae25d88216e 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -293,6 +293,7 @@
/* Intel-defined CPU features, CPUID level 0x00000007:1 (EAX), word 12 */
#define X86_FEATURE_AVX512_BF16 (12*32+ 5) /* AVX512 BFLOAT16 instructions */
+#define X86_FEATURE_LAM (12*32+26) /* Linear Address Masking */
/* AMD-defined CPU features, CPUID level 0x80000008 (EBX), word 13 */
#define X86_FEATURE_CLZERO (13*32+ 0) /* CLZERO instruction */
diff --git a/arch/x86/include/uapi/asm/processor-flags.h b/arch/x86/include/uapi/asm/processor-flags.h
index bcba3c643e63..f2a4a53308e2 100644
--- a/arch/x86/include/uapi/asm/processor-flags.h
+++ b/arch/x86/include/uapi/asm/processor-flags.h
@@ -82,6 +82,10 @@
#define X86_CR3_PCID_BITS 12
#define X86_CR3_PCID_MASK (_AC((1UL << X86_CR3_PCID_BITS) - 1, UL))
+#define X86_CR3_LAM_U48_BIT 61 /* Activate LAM for userspace, 62:48 bits masked */
+#define X86_CR3_LAM_U48 _BITULL(X86_CR3_LAM_U48_BIT)
+#define X86_CR3_LAM_U57_BIT 62 /* Activate LAM for userspace, 62:57 bits masked */
+#define X86_CR3_LAM_U57 _BITULL(X86_CR3_LAM_U57_BIT)
#define X86_CR3_PCID_NOFLUSH_BIT 63 /* Preserve old PCID */
#define X86_CR3_PCID_NOFLUSH _BITULL(X86_CR3_PCID_NOFLUSH_BIT)
@@ -130,6 +134,8 @@
#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_LAM_SUP_BIT 28 /* LAM for supervisor pointers */
+#define X86_CR4_LAM_SUP _BITUL(X86_CR4_LAM_SUP_BIT)
/*
* x86-64 Task Priority Register, CR8
--
2.26.2