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/services/arm_arch_svc/arm_arch_svc_setup.c b/services/arm_arch_svc/arm_arch_svc_setup.c
new file mode 100644
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
+);