The branch main has been updated by andrew:
URL:
https://cgit.FreeBSD.org/src/commit/?id=89bb17ec3b0260fa0d9c30a23b7e5f73fc5917f4
commit 89bb17ec3b0260fa0d9c30a23b7e5f73fc5917f4
Author: Andrew Turner <and...@freebsd.org>
AuthorDate: 2025-06-02 09:57:44 +0000
Commit: Andrew Turner <and...@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
