D39748.id120836.diff
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	diff --git a/sys/arm64/arm64/ptrauth.c b/sys/arm64/arm64/ptrauth.c
	--- a/sys/arm64/arm64/ptrauth.c
	+++ b/sys/arm64/arm64/ptrauth.c
	@@ -59,6 +59,31 @@
	void ptrauth_exit_el0(struct thread *);
	void ptrauth_enter_el0(struct thread *);

	+static bool
	+ptrauth_disable(void)
	+{
	+ const char family, maker, *product;
	+
	+ family = kern_getenv("smbios.system.family");
	+ maker = kern_getenv("smbios.system.maker");
	+ product = kern_getenv("smbios.system.product");
	+ if (family == NULL \|\| maker == NULL \|\| product == NULL)
	+ return (false);
	+
	+ /*
	+ * The Dev Kit appears to be configured to trap upon access to PAC
	+ * registers, but the kernel boots at EL1 and so we have no way to
	+ * inspect or change this configuration. As a workaround, simply
	+ * disable PAC on this platform.
	+ */
	+ if (strcmp(maker, "Microsoft Corporation") == 0 &&
	+ strcmp(family, "Surface") == 0 &&
	+ strcmp(product, "Windows Dev Kit 2023") == 0)
	+ return (true);
	+
	+ return (false);
	+}
	+
	void
	ptrauth_init(void)
	{
	@@ -77,7 +102,11 @@
	return;
	}

	- get_kernel_reg(ID_AA64ISAR1_EL1, &isar1);
	+ if (!get_kernel_reg(ID_AA64ISAR1_EL1, &isar1))
	+ return;
	+
	+ if (ptrauth_disable())
	+ return;

	/*
	* This assumes if there is pointer authentication on the boot CPU