The following commit has been merged into the x86/fred branch of tip:
Commit-ID: 51c158f7aaccc6f6423a61a1df4a0d4c0d9d22a9
Gitweb: https://git.kernel.org/tip/51c158f7aaccc6f6423a61a1df4a0d4c0d9d22a9
Author: H. Peter Anvin (Intel) <hpa@xxxxxxxxx>
AuthorDate: Tue, 05 Dec 2023 02:49:55 -08:00
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Thu, 25 Jan 2024 19:10:30 +01:00
x86/cpufeatures: Add the CPU feature bit for FRED
Any FRED enabled CPU will always have the following features as its
baseline:
1) LKGS, load attributes of the GS segment but the base address into
the IA32_KERNEL_GS_BASE MSR instead of the GS segment’s descriptor
cache.
2) WRMSRNS, non-serializing WRMSR for faster MSR writes.
Signed-off-by: H. Peter Anvin (Intel) <hpa@xxxxxxxxx>
Signed-off-by: Xin Li <xin3.li@xxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Tested-by: Shan Kang <shan.kang@xxxxxxxxx>
Link: https://lore.kernel.org/r/20231205105030.8698-7-xin3.li@xxxxxxxxx
---
arch/x86/include/asm/cpufeatures.h | 1 +
arch/x86/kernel/cpu/cpuid-deps.c | 2 ++
tools/arch/x86/include/asm/cpufeatures.h | 1 +
3 files changed, 4 insertions(+)
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index bd05c75..ccbf914 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -326,6 +326,7 @@
#define X86_FEATURE_FZRM (12*32+10) /* "" Fast zero-length REP MOVSB */
#define X86_FEATURE_FSRS (12*32+11) /* "" Fast short REP STOSB */
#define X86_FEATURE_FSRC (12*32+12) /* "" Fast short REP {CMPSB,SCASB} */
+#define X86_FEATURE_FRED (12*32+17) /* Flexible Return and Event Delivery */
#define X86_FEATURE_LKGS (12*32+18) /* "" Load "kernel" (userspace) GS */
#define X86_FEATURE_WRMSRNS (12*32+19) /* "" Non-serializing WRMSR */
#define X86_FEATURE_AMX_FP16 (12*32+21) /* "" AMX fp16 Support */
diff --git a/arch/x86/kernel/cpu/cpuid-deps.c b/arch/x86/kernel/cpu/cpuid-deps.c
index e462c1d..b717420 100644
--- a/arch/x86/kernel/cpu/cpuid-deps.c
+++ b/arch/x86/kernel/cpu/cpuid-deps.c
@@ -82,6 +82,8 @@ static const struct cpuid_dep cpuid_deps[] = {
{ X86_FEATURE_XFD, X86_FEATURE_XGETBV1 },
{ X86_FEATURE_AMX_TILE, X86_FEATURE_XFD },
{ X86_FEATURE_SHSTK, X86_FEATURE_XSAVES },
+ { X86_FEATURE_FRED, X86_FEATURE_LKGS },
+ { X86_FEATURE_FRED, X86_FEATURE_WRMSRNS },
{}
};
diff --git a/tools/arch/x86/include/asm/cpufeatures.h b/tools/arch/x86/include/asm/cpufeatures.h
index 8792841..953e6ef 100644
--- a/tools/arch/x86/include/asm/cpufeatures.h
+++ b/tools/arch/x86/include/asm/cpufeatures.h
@@ -321,6 +321,7 @@
#define X86_FEATURE_FZRM (12*32+10) /* "" Fast zero-length REP MOVSB */
#define X86_FEATURE_FSRS (12*32+11) /* "" Fast short REP STOSB */
#define X86_FEATURE_FSRC (12*32+12) /* "" Fast short REP {CMPSB,SCASB} */
+#define X86_FEATURE_FRED (12*32+17) /* Flexible Return and Event Delivery */
#define X86_FEATURE_LKGS (12*32+18) /* "" Load "kernel" (userspace) GS */
#define X86_FEATURE_WRMSRNS (12*32+19) /* "" Non-serializing WRMSR */
#define X86_FEATURE_AMX_FP16 (12*32+21) /* "" AMX fp16 Support */
|