[RFC 01/11] arm64: Add an SMCCC function IDs header

[Florent Revest <florent.revest@arm.com>]

The ARM SMC Calling Convention (DEN 0028B) introduces function IDs for
hypercalls, given in the x0 register during an SMC or HVC from a guest.

The document defines ranges of function IDs targeting different kinds of
hypervisors or supervisors.

Two ID ranges are of particular interest for the kernel:
    - Standard hypervisor service calls
    - Vendor specific hypervisor service calls

This patch introduces a couple of useful macros when working with SMCCC.
They provide defines of those ID ranges to be used by HVC handling (KVM)
or calling. (e.g: to leverage paravirtualized services)

The document also defines standard return values to be written into x0
after a hypercall handling. Once again, those macros can potentially be
used from both the hypervisor or the guest.

Signed-off-by: Florent Revest <florent.revest@arm.com>
---
 include/linux/smccc_fn.h | 50 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)
 create mode 100644 include/linux/smccc_fn.h

diff --git a/include/linux/smccc_fn.h b/include/linux/smccc_fn.h
new file mode 100644
index 0000000..f08145d
--- /dev/null
+++ b/include/linux/smccc_fn.h
@@ -0,0 +1,50 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Copyright (C) 2017 ARM Limited
+ */
+
+#ifndef __LINUX_SMCCC_FN_H
+#define __LINUX_SMCCC_FN_H
+
+/*
+ * Standard return values
+ */
+
+#define SMCCC_STD_RET_SUCCESS          0
+#define SMCCC_STD_RET_UNKNOWN_ID       -1
+
+
+/*
+ * SMC32
+ */
+
+/* Standard hypervisor services interface */
+#define SMCCC32_STD_HYP_FN_BASE                0x85000000
+#define SMCCC32_STD_HYP_FN(n)          (SMCCC32_STD_HYP_FN_BASE + (n))
+
+/* Vendor specific hypervisor services interface */
+#define SMCCC32_VDR_HYP_FN_BASE                0x86000000
+#define SMCCC32_VDR_HYP_FN(n)          (SMCCC32_VDR_HYP_FN_BASE + (n))
+
+
+/*
+ * SMC64
+ */
+
+/* Standard hypervisor services interface */
+#define SMCCC64_STD_HYP_FN_BASE                0xc5000000
+#define SMCCC64_STD_HYP_FN(n)          (SMCCC64_STD_HYP_FN_BASE + (n))
+
+/* Vendor specific hypervisor services interface */
+#define SMCCC64_VDR_HYP_FN_BASE                0xc6000000
+#define SMCCC64_VDR_HYP_FN(n)          (SMCCC64_VDR_HYP_FN_BASE + (n))
+
+#endif /* __LINUX_SMCCC_FN_H */
--
1.9.1

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