On 11. 10. 22, 2:08, Elliot Berman wrote:

Add hypercalls to identify when Linux is running a virtual machine under
Gunyah.

There are two calls to help identify Gunyah:

1. gh_hypercall_get_uid() returns a UID when running under a Gunyah
    hypervisor.
2. gh_hypercall_hyp_identify() returns build information and a set of
    feature flags that are supported by Gunyah.

...

...

+/**
+ * gh_hypercall_get_uid() - Returns a UID when running under a Gunyah hypervisor.
+ * @uid: An array of 4 u32's (u32 uid[4];)
+ *
+ * The UID will be either QC_HYP_UID or GUNYAH_UID defined in include/asm-generic/gunyah.h.
+ * QC_HYP_UID is returned on platforms using Qualcomm's version of Gunyah.
+ * GUNYAH_UID is returned on platforms using open source version of Gunyah.
+ * If the uid is not one of the above two UIDs, then it is assumed that the hypervisor or firmware
+ * is not Gunyah.
+ */
+void gh_hypercall_get_uid(u32 *uid)

So why this isn't u32 uid[4], or u32 uid[static 4] to aid the compiler 
(and limit users)?

+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_hvc(GH_HYPERCALL_CALL_UID, &res);
+
+	uid[0] = res.a0;
+	uid[1] = res.a1;
+	uid[2] = res.a2;
+	uid[3] = res.a3;
+}
+EXPORT_SYMBOL_GPL(gh_hypercall_get_uid);

...

...

+#define GH_API_INFO_API_VERSION(x)	(((x) >> 0) & 0x3fff)
+#define GH_API_INFO_BIG_ENDIAN(x)	(((x) >> 14) & 1)
+#define GH_API_INFO_IS_64BIT(x)		(((x) >> 15) & 1)
+#define GH_API_INFO_VARIANT(x)		(((x) >> 56) & 0xff)

Use GET_FIELD()?

regards,
-- 
-- 
js
suse labs