[PATCH] x86: Detect APX_NCI_NDD_NF

From 948bcc5b8d38aa22a100d84b20bb47bef1fb0c87 Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <[email protected]>
Date: Mon, 31 Aug 2026 07:21:12 +0800
Subject: [PATCH] x86: Detect APX_NCI_NDD_NF

Detect APX_NCI_NDD_NF specified in Intel APX specification published in
January 2026:

https://www.intel.com/content/www/us/en/developer/articles/technical/intel-sdm.html

Signed-off-by: H.J. Lu <[email protected]>
---
 manual/platform.texi               |  5 +++++
 sysdeps/x86/bits/platform/x86.h    |  9 ++++++++-
 sysdeps/x86/cpu-features.c         | 15 +++++++++++++++
 sysdeps/x86/include/cpu-features.h | 17 ++++++++++++++++-
 sysdeps/x86/tst-get-cpu-features.c |  2 ++
 5 files changed, 46 insertions(+), 2 deletions(-)

diff --git a/manual/platform.texi b/manual/platform.texi
index cb89e4432d..011d3501fb 100644
--- a/manual/platform.texi
+++ b/manual/platform.texi
@@ -217,6 +217,11 @@ The supported processor features are:
 @item
 @code{APX_F} -- The APX instruction extensions.
 
+@item
+@code{APX_NCI_NDD_NF} -- The instruction extensions with APX new
+conditional instructions (NCI), explicit new data destination (NDD)
+controls, and explicit flags suppression (NF).
+
 @item
 @code{ARCH_CAPABILITIES} -- IA32_ARCH_CAPABILITIES MSR.
 
diff --git a/sysdeps/x86/bits/platform/x86.h b/sysdeps/x86/bits/platform/x86.h
index c646e36b28..7b81a07465 100644
--- a/sysdeps/x86/bits/platform/x86.h
+++ b/sysdeps/x86/bits/platform/x86.h
@@ -32,7 +32,8 @@ enum
   CPUID_INDEX_19,
   CPUID_INDEX_14_ECX_0,
   CPUID_INDEX_24_ECX_0,
-  CPUID_INDEX_24_ECX_1
+  CPUID_INDEX_24_ECX_1,
+  CPUID_INDEX_29_ECX_0
 };
 
 struct cpuid_feature
@@ -345,4 +346,10 @@ enum
 
   x86_cpu_AVX10_V1_AUX		= x86_cpu_index_24_ecx_1_ecx + 2,
   x86_cpu_AVX10_V2_AUX		= x86_cpu_index_24_ecx_1_ecx + 3,
+
+  x86_cpu_index_29_ecx_0_ebx
+    = (CPUID_INDEX_29_ECX_0 * 8 * 4 * sizeof (unsigned int)
+       + cpuid_register_index_ebx * 8 * sizeof (unsigned int)),
+
+  x86_cpu_APX_NCI_NDD_NF	= x86_cpu_index_29_ecx_0_ebx,
 };
diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c
index ecbcb3c78b..0b744f95a9 100644
--- a/sysdeps/x86/cpu-features.c
+++ b/sysdeps/x86/cpu-features.c
@@ -288,6 +288,21 @@ update_active (struct cpu_features *cpu_features)
 	    }
 	}
 
+      if (cpu_features->basic.max_cpuid >= 0x29)
+	{
+	  __cpuid_count
+	    (0x29, 0,
+	     cpu_features->features[CPUID_INDEX_29_ECX_0].cpuid.eax,
+	     cpu_features->features[CPUID_INDEX_29_ECX_0].cpuid.ebx,
+	     cpu_features->features[CPUID_INDEX_29_ECX_0].cpuid.ecx,
+	     cpu_features->features[CPUID_INDEX_29_ECX_0].cpuid.edx);
+
+	  if (CPU_FEATURES_CPU_P (cpu_features, APX_F))
+	    {
+	      CPU_FEATURE_SET_ACTIVE (cpu_features, APX_NCI_NDD_NF);
+	    }
+	}
+
       /* Are XTILECFG and XTILEDATA states usable?  */
       if ((xcrlow & (bit_XTILECFG_state | bit_XTILEDATA_state))
 	  == (bit_XTILECFG_state | bit_XTILEDATA_state))
diff --git a/sysdeps/x86/include/cpu-features.h b/sysdeps/x86/include/cpu-features.h
index ec9076e261..bb632d8ce1 100644
--- a/sysdeps/x86/include/cpu-features.h
+++ b/sysdeps/x86/include/cpu-features.h
@@ -29,7 +29,7 @@
 
 enum
 {
-  CPUID_INDEX_MAX = CPUID_INDEX_24_ECX_1 + 1
+  CPUID_INDEX_MAX = CPUID_INDEX_29_ECX_0 + 1
 };
 
 enum
@@ -348,6 +348,11 @@ enum
 #define bit_cpu_AVX10_V1_AUX	(1u << 2)
 #define bit_cpu_AVX10_V2_AUX	(1u << 3)
 
+/* CPUID_INDEX_29_ECX_0.  */
+
+/* EBX.  */
+#define bit_cpu_APX_NCI_NDD_NF	(1u << 0)
+
 /* CPUID_INDEX_1.  */
 
 /* ECX.  */
@@ -610,6 +615,11 @@ enum
 #define index_AVX10_V1_AUX	CPUID_INDEX_24_ECX_1
 #define index_AVX10_V2_AUX	CPUID_INDEX_24_ECX_1
 
+/* CPUID_INDEX_29_ECX_0.  */
+
+/* EBX.  */
+#define index_cpu_APX_NCI_NDD_NF CPUID_INDEX_29_ECX_0
+
 /* CPUID_INDEX_1.  */
 
 /* ECX.  */
@@ -872,6 +882,11 @@ enum
 #define reg_AVX10_V1_AUX	ecx
 #define reg_AVX10_V2_AUX	ecx
 
+/* CPUID_INDEX_29_ECX_0.  */
+
+/* EBX.  */
+#define reg_APX_NCI_NDD_NF	ebx
+
 /* PREFERRED_FEATURE_INDEX_1.  First define the bitindex values
    sequentially, then define the bit_arch* and index_arch_* lookup
    constants.  */
diff --git a/sysdeps/x86/tst-get-cpu-features.c b/sysdeps/x86/tst-get-cpu-features.c
index c6af1793fe..83c5cbc29e 100644
--- a/sysdeps/x86/tst-get-cpu-features.c
+++ b/sysdeps/x86/tst-get-cpu-features.c
@@ -224,6 +224,7 @@ do_test (void)
   CHECK_CPU_FEATURE_PRESENT (AESKLE);
   CHECK_CPU_FEATURE_PRESENT (WIDE_KL);
   CHECK_CPU_FEATURE_PRESENT (PTWRITE);
+  CHECK_CPU_FEATURE_PRESENT (APX_NCI_NDD_NF);
 
   printf ("Possible CPU features:\n");
   CHECK_CPU_FEATURE_ACTIVE (SSE3);
@@ -397,6 +398,7 @@ do_test (void)
   CHECK_CPU_FEATURE_ACTIVE (AESKLE);
   CHECK_CPU_FEATURE_ACTIVE (WIDE_KL);
   CHECK_CPU_FEATURE_ACTIVE (PTWRITE);
+  CHECK_CPU_FEATURE_ACTIVE (APX_NCI_NDD_NF);
 
   unsigned int version = x86_get_avx10_version ();
   printf ("AVX10 version: %d\n", version);
-- 
2.55.0