git: 89bb17ec3b02 - main - arm64: Mask out the PAC ID fields when disabled

The branch main has been updated by andrew:

URL: https://cgit.FreeBSD.org/src/commit/?id=89bb17ec3b0260fa0d9c30a23b7e5f73fc5917f4

commit 89bb17ec3b0260fa0d9c30a23b7e5f73fc5917f4
Author:     Andrew Turner <andrew@FreeBSD.org>
AuthorDate: 2025-06-02 09:57:44 +0000
Commit:     Andrew Turner <andrew@FreeBSD.org>
CommitDate: 2025-06-02 09:57:44 +0000

    arm64: Mask out the PAC ID fields when disabled
    
    When we disable PAC we need to mask out the ID registers for userspace.
    Call update_special_reg to mask them out so userspace gets a correct
    view of the registers and hwcaps.
    
    Sponsored by:   Arm Ltd
    Differential Revision:  https://reviews.freebsd.org/D50573
---
 sys/arm64/arm64/ptrauth.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/sys/arm64/arm64/ptrauth.c b/sys/arm64/arm64/ptrauth.c
index 7ef958b2e03c..dd36e66c85bb 100644
--- a/sys/arm64/arm64/ptrauth.c
+++ b/sys/arm64/arm64/ptrauth.c
@@ -97,14 +97,14 @@ ptrauth_check(const struct cpu_feat *feat __unused, u_int midr __unused)
 	if (!pac_enable) {
 		if (boothowto & RB_VERBOSE)
 			printf("Pointer authentication is disabled\n");
-		return (false);
+		goto out;
 	}
 
 	if (!get_kernel_reg(ID_AA64ISAR1_EL1, &isar1))
-		return (false);
+		goto out;
 
 	if (ptrauth_disable())
-		return (false);
+		goto out;
 
 	/*
 	 * This assumes if there is pointer authentication on the boot CPU
@@ -113,6 +113,12 @@ ptrauth_check(const struct cpu_feat *feat __unused, u_int midr __unused)
 	 */
 	return (ID_AA64ISAR1_APA_VAL(isar1) > 0 ||
 	    ID_AA64ISAR1_API_VAL(isar1) > 0);
+
+out:
+	update_special_reg(ID_AA64ISAR1_EL1, ID_AA64ISAR1_API_MASK |
+	    ID_AA64ISAR1_APA_MASK | ID_AA64ISAR1_GPA_MASK |
+	    ID_AA64ISAR1_GPI_MASK, 0);
+	return (false);
 }
 
 static void