[Minios-devel] [UNIKRAFT PATCHv6 26/37] plat/common: Implement CPU halt function for arm64

[Wei Chen <wei.chen@xxxxxxx>]

From: Wei Chen <Wei.Chen@xxxxxxx>

Halts the CPU until the next external interrupt is fired.
For Arm, we can use WFI to implement this feature.

Signed-off-by: Wei Chen <Wei.Chen@xxxxxxx>
Reviewed-by: Simon Kuenzer <simon.kuenzer@xxxxxxxxx>
---
 plat/common/arm/cpu_native.c        | 45 +++++++++++++++++++++++++++++
 plat/common/include/arm/arm64/cpu.h |  3 ++
 plat/common/include/cpu.h           |  6 ++++
 plat/kvm/Makefile.uk                |  1 +
 4 files changed, 55 insertions(+)
 create mode 100644 plat/common/arm/cpu_native.c

diff --git a/plat/common/arm/cpu_native.c b/plat/common/arm/cpu_native.c
new file mode 100644
index 0000000..e7603ac
--- /dev/null
+++ b/plat/common/arm/cpu_native.c
@@ -0,0 +1,45 @@
+/* SPDX-License-Identifier: BSD-3-Clause */
+/*
+ * Authors: Wei Chen <wei.chen@xxxxxxx>
+ *
+ * Copyright (c) 2018, Arm Ltd., All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the copyright holder nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ * THIS HEADER MAY NOT BE EXTRACTED OR MODIFIED IN ANY WAY.
+ */
+#include <cpu.h>
+#include <uk/assert.h>
+#include <arm/cpu_defs.h>
+
+/*
+ * Halts the CPU until the next external interrupt is fired. For Arm,
+ * we can use WFI to implement this feature.
+ */
+void halt(void)
+{
+       __asm__ __volatile__("wfi");
+}
diff --git a/plat/common/include/arm/arm64/cpu.h 
b/plat/common/include/arm/arm64/cpu.h
index 0426ebd..6fd2a16 100644
--- a/plat/common/include/arm/arm64/cpu.h
+++ b/plat/common/include/arm/arm64/cpu.h
@@ -113,3 +113,6 @@ typedef int (*smcc_psci_callfn_t)(uint32_t, uint64_t, 
uint64_t, uint64_t);
 extern smcc_psci_callfn_t smcc_psci_call;
 int32_t smcc_psci_hvc_call(uint32_t, uint64_t, uint64_t, uint64_t);
 int32_t smcc_psci_smc_call(uint32_t, uint64_t, uint64_t, uint64_t);
+
+/* CPU native APIs */
+void halt(void);
diff --git a/plat/common/include/cpu.h b/plat/common/include/cpu.h
index bf43876..ca2e15e 100644
--- a/plat/common/include/cpu.h
+++ b/plat/common/include/cpu.h
@@ -44,5 +44,11 @@
 #error "Add cpu.h for current architecture."
 #endif
 
+#define __CPU_HALT()           \
+({                             \
+       local_irq_disable();    \
+               for (;;)        \
+                       halt(); \
+})
 
 #endif /* __PLAT_CMN_CPU_H__ */
diff --git a/plat/kvm/Makefile.uk b/plat/kvm/Makefile.uk
index b3202be..06e4fc3 100644
--- a/plat/kvm/Makefile.uk
+++ b/plat/kvm/Makefile.uk
@@ -54,6 +54,7 @@ ifeq ($(CONFIG_ARCH_ARM_64),y)
 ifeq ($(findstring y,$(CONFIG_KVM_KERNEL_SERIAL_CONSOLE) 
$(CONFIG_KVM_DEBUG_SERIAL_CONSOLE)),y)
 LIBKVMPLAT_SRCS-$(CONFIG_ARCH_ARM_64) += 
$(UK_PLAT_COMMON_BASE)/arm/pl011.c|common
 endif
+LIBKVMPLAT_SRCS-$(CONFIG_ARCH_ARM_64) += 
$(UK_PLAT_COMMON_BASE)/arm/cpu_native.c|common
 LIBKVMPLAT_SRCS-$(CONFIG_ARCH_ARM_64) += 
$(UK_PLAT_COMMON_BASE)/arm/cache64.S|common
 LIBKVMPLAT_SRCS-$(CONFIG_ARCH_ARM_64) += 
$(UK_PLAT_COMMON_BASE)/arm/psci_arm64.S|common
 LIBKVMPLAT_SRCS-$(CONFIG_ARCH_ARM_64) += 
$(UK_PLAT_COMMON_BASE)/arm/time.c|common
-- 
2.17.1


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