Implement support for SMCCC v1.1

SMCCC v1.1 comes with a relaxed calling convention for AArch64
callers.  The caller only needs to save x0-x3 before doing an SMC
call.

This patch adds support for SMCCC_VERSION and SMCCC_ARCH_FEATURES.

Refer to "Firmware Interfaces for mitigating CVE_2017_5715 System
Software on Arm Systems"[0] for more information.

[0] https://developer.arm.com/-/media/developer/pdf/ARM%20DEN%200070A%20Firmware%20interfaces%20for%20mitigating%20CVE-2017-5715_V1.0.pdf

Change-Id: If5b1c55c17d6c5c7cb9c2c3ed355d3a91cdad0a9
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>

diff --git a/bl31/bl31.mk b/bl31/bl31.mk
index 2db48564e677fc42868181f134d0fe4c7986dd14..886d3016ff4dee9803ac6276184f9437b2eac574 100644 (file)
--- a/bl31/bl31.mk
+++ b/bl31/bl31.mk
@@ -1,5 +1,5 @@
 #
-# Copyright (c) 2013-2017, ARM Limited and Contributors. All rights reserved.
+# Copyright (c) 2013-2018, ARM Limited and Contributors. All rights reserved.
 #
 # SPDX-License-Identifier: BSD-3-Clause
 #
@@ -23,6 +23,7 @@ BL31_SOURCES          +=      bl31/bl31_main.c                                \
                                bl31/bl31_context_mgmt.c                        \
                                common/runtime_svc.c                            \
                                plat/common/aarch64/platform_mp_stack.S         \
+                               services/arm_arch_svc/arm_arch_svc_setup.c      \
                                services/std_svc/std_svc_setup.c                \
                                ${PSCI_LIB_SOURCES}                             \
                                ${SPM_SOURCES}                                  \

diff --git a/include/lib/smcc.h b/include/lib/smcc.h
index 13b1e7ac4709062693b6b259d0c2549b0044b503..a273b3af4a90ea9e9328389c93aaf228f313f471 100644 (file)
--- a/include/lib/smcc.h
+++ b/include/lib/smcc.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2017, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2016-2018, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -67,6 +67,11 @@
 #include <cassert.h>
 #include <stdint.h>
 
+#define SMCCC_MAJOR_VERSION U(1)
+#define SMCCC_MINOR_VERSION U(1)
+
+#define MAKE_SMCCC_VERSION(_major, _minor) (((_major) << 16) | (_minor))
+
 /* Various flags passed to SMC handlers */
 #define SMC_FROM_SECURE                (U(0) << 0)
 #define SMC_FROM_NON_SECURE    (U(1) << 0)
@@ -78,6 +83,10 @@
 #define is_std_svc_call(_fid)          ((((_fid) >> FUNCID_OEN_SHIFT) & \
                                           FUNCID_OEN_MASK) == OEN_STD_START)
 
+/* The macro below is used to identify a Arm Architectural Service SMC call */
+#define is_arm_arch_svc_call(_fid)     ((((_fid) >> FUNCID_OEN_SHIFT) & \
+                                          FUNCID_OEN_MASK) == OEN_ARM_START)
+
 /* The macro below is used to identify a valid Fast SMC call */
 #define is_valid_fast_smc(_fid)                ((!(((_fid) >> 16) & U(0xff))) && \
                                           (GET_SMC_TYPE(_fid) == SMC_TYPE_FAST))

diff --git a/include/services/arm_arch_svc.h b/include/services/arm_arch_svc.h
new file mode 100644 (file)
index 0000000..2961601
--- /dev/null
+++ b/include/services/arm_arch_svc.h
@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef __ARM_ARCH_SVC_H__
+#define __ARM_ARCH_SVC_H__
+
+#define SMCCC_VERSION                  U(0x80000000)
+#define SMCCC_ARCH_FEATURES            U(0x80000001)
+#define SMCCC_ARCH_WORKAROUND_1                U(0x80008000)
+
+#endif /* __ARM_ARCH_SVC_H__ */

diff --git a/services/arm_arch_svc/arm_arch_svc_setup.c b/services/arm_arch_svc/arm_arch_svc_setup.c
new file mode 100644 (file)
index 0000000..eedac86
--- /dev/null
+++ b/services/arm_arch_svc/arm_arch_svc_setup.c
@@ -0,0 +1,74 @@
+/*
+ * Copyright (c) 2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <arm_arch_svc.h>
+#include <debug.h>
+#include <runtime_svc.h>
+#include <smcc.h>
+#include <smcc_helpers.h>
+
+static int32_t smccc_version(void)
+{
+       return MAKE_SMCCC_VERSION(SMCCC_MAJOR_VERSION, SMCCC_MINOR_VERSION);
+}
+
+static int32_t smccc_arch_features(u_register_t arg)
+{
+       switch (arg) {
+       case SMCCC_VERSION:
+       case SMCCC_ARCH_FEATURES:
+               return SMC_OK;
+#if WORKAROUND_CVE_2017_5715
+       case SMCCC_ARCH_WORKAROUND_1:
+               return SMC_OK;
+#endif
+       default:
+               return SMC_UNK;
+       }
+}
+
+/*
+ * Top-level Arm Architectural Service SMC handler.
+ */
+uintptr_t arm_arch_svc_smc_handler(uint32_t smc_fid,
+       u_register_t x1,
+       u_register_t x2,
+       u_register_t x3,
+       u_register_t x4,
+       void *cookie,
+       void *handle,
+       u_register_t flags)
+{
+       switch (smc_fid) {
+       case SMCCC_VERSION:
+               SMC_RET1(handle, smccc_version());
+       case SMCCC_ARCH_FEATURES:
+               SMC_RET1(handle, smccc_arch_features(x1));
+#if WORKAROUND_CVE_2017_5715
+       case SMCCC_ARCH_WORKAROUND_1:
+               /*
+                * The workaround has already been applied on affected PEs
+                * during entry to EL3.  On unaffected PEs, this function
+                * has no effect.
+                */
+               SMC_RET0(handle);
+#endif
+       default:
+               WARN("Unimplemented Arm Architecture Service Call: 0x%x \n",
+                       smc_fid);
+               SMC_RET1(handle, SMC_UNK);
+       }
+}
+
+/* Register Standard Service Calls as runtime service */
+DECLARE_RT_SVC(
+               arm_arch_svc,
+               OEN_ARM_START,
+               OEN_ARM_END,
+               SMC_TYPE_FAST,
+               NULL,
+               arm_arch_svc_smc_handler
+);