git: cd94485281f3 - main - arm64: Add FEAT_ALWAYS_ENABLE to cpu_feat

The branch main has been updated by andrew:

URL: https://cgit.FreeBSD.org/src/commit/?id=cd94485281f3fc6ae5414180420527ce11846742

commit cd94485281f3fc6ae5414180420527ce11846742
Author:     Andrew Turner <andrew@FreeBSD.org>
AuthorDate: 2026-06-18 13:34:47 +0000
Commit:     Andrew Turner <andrew@FreeBSD.org>
CommitDate: 2026-06-18 14:56:53 +0000

    arm64: Add FEAT_ALWAYS_ENABLE to cpu_feat
    
    A use for it has been found in the GICv5 driver where we need to read
    the Interrupt Affinity ID early in the boot on the secondary CPUs.
    
    Sponsored by:   Arm Ltd
    Differential Revision:  https://reviews.freebsd.org/D54249
---
 sys/arm64/arm64/cpu_feat.c   | 24 +++++++++++++-----------
 sys/arm64/include/cpu_feat.h |  7 ++++++-
 2 files changed, 19 insertions(+), 12 deletions(-)

diff --git a/sys/arm64/arm64/cpu_feat.c b/sys/arm64/arm64/cpu_feat.c
index 94114d47f846..8b8af5fc7cf7 100644
--- a/sys/arm64/arm64/cpu_feat.c
+++ b/sys/arm64/arm64/cpu_feat.c
@@ -87,17 +87,19 @@ enable_cpu_feat(uint32_t stage)
 		if (check_status == FEAT_ALWAYS_DISABLE)
 			goto next;
 
-		/* The user disabled the feature */
-		if ((feat->feat_flags & CPU_FEAT_USER_DISABLED) != 0)
-			goto next;
-
-		/*
-		 * The feature was disabled by default and the user
-		 * didn't enable it then skip.
-		 */
-		if (check_status == FEAT_DEFAULT_DISABLE &&
-		    (feat->feat_flags & CPU_FEAT_USER_ENABLED) == 0)
-			goto next;
+		if (check_status != FEAT_ALWAYS_ENABLE) {
+			/* The user disabled the feature */
+			if ((feat->feat_flags & CPU_FEAT_USER_DISABLED) != 0)
+				goto next;
+
+			/*
+			 * The feature was disabled by default and the user
+			 * didn't enable it then skip.
+			 */
+			if (check_status == FEAT_DEFAULT_DISABLE &&
+			    (feat->feat_flags & CPU_FEAT_USER_ENABLED) == 0)
+				goto next;
+		}
 
 		/*
 		 * Check if the feature has any errata that may need a
diff --git a/sys/arm64/include/cpu_feat.h b/sys/arm64/include/cpu_feat.h
index 6a311d4000bb..5eff7f589d8b 100644
--- a/sys/arm64/include/cpu_feat.h
+++ b/sys/arm64/include/cpu_feat.h
@@ -62,7 +62,12 @@ typedef enum {
 	 */
 	FEAT_DEFAULT_ENABLE,
 
-	/* We could add FEAT_ALWAYS_ENABLE if a need was found. */
+	/*
+	 * Always enabled. Used when there is no way for the kernel to
+	 * work without the feature, e.g. configuring the interrupt
+	 * controller.
+	 */
+	FEAT_ALWAYS_ENABLE,
 } cpu_feat_en;
 
 #define	CPU_FEAT_STAGE_MASK	0x00000001