arch/x86_64: add spinlock support

Add spinlock support for x86_64, needed for SMP

Signed-off-by: p-szafonimateusz <p-szafonimateusz@xiaomi.com>

arch/Kconfig

@@ -132,6 +132,7 @@ config ARCH_X86_64
 	select ARCH_HAVE_TCBINFO
 	select ARCH_HAVE_FPU
 	select ARCH_HAVE_DPFPU
+	select ARCH_HAVE_TESTSET
 	select LIBC_ARCH_ELF_64BIT if LIBC_ARCH_ELF
 	---help---
 		x86-64 architectures.

arch/x86_64/include/spinlock.h

@@ -0,0 +1,98 @@
+/****************************************************************************
+ * arch/x86_64/include/spinlock.h
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+#ifndef __ARCH_X86_64_INCLUDE_SPINLOCK_H
+#define __ARCH_X86_64_INCLUDE_SPINLOCK_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#ifndef __ASSEMBLY__
+#  include <stdint.h>
+#endif /* __ASSEMBLY__ */
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/* Spinlock states */
+
+#define SP_UNLOCKED 0  /* The Un-locked state */
+#define SP_LOCKED   1  /* The Locked state */
+
+/* Memory barriers for use with NuttX spinlock logic
+ *
+ * Data Memory Barrier (DMB) acts as a memory barrier. It ensures that all
+ * explicit memory accesses that appear in program order before the DMB
+ * instruction are observed before any explicit memory accesses that appear
+ * in program order after the DMB instruction. It does not affect the
+ * ordering of any other instructions executing on the processor
+ *
+ * Data Synchronization Barrier (DSB) acts as a special kind of memory
+ * barrier. No instruction in program order after this instruction executes
+ * until this instruction completes. This instruction completes when: (1) All
+ * explicit memory accesses before this instruction complete, and (2) all
+ * Cache, Branch predictor and TLB maintenance operations before this
+ * instruction complete.
+ *
+ */
+
+#define SP_DSB(n) __asm__ __volatile__ ("mfence")
+#define SP_DMB(n) __asm__ __volatile__ ("mfence")
+
+/****************************************************************************
+ * Public Types
+ ****************************************************************************/
+
+#ifndef __ASSEMBLY__
+
+/* The Type of a spinlock */
+
+typedef uintptr_t spinlock_t;
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_testset
+ *
+ * Description:
+ *   Perform an atomic test and set operation on the provided spinlock.
+ *
+ *   This function must be provided via the architecture-specific logic.
+ *
+ * Input Parameters:
+ *   lock - The address of spinlock object.
+ *
+ * Returned Value:
+ *   The spinlock is always locked upon return.  The value of previous value
+ *   of the spinlock variable is returned, either SP_LOCKED if the spinlock
+ *   as previously locked (meaning that the test-and-set operation failed to
+ *   obtain the lock) or SP_UNLOCKED if the spinlock was previously unlocked
+ *   (meaning that we successfully obtained the lock)
+ *
+ ****************************************************************************/
+
+/* See prototype in nuttx/include/nuttx/spinlock.h */
+
+#endif /* __ASSEMBLY__ */
+#endif /* __ARCH_X86_64_INCLUDE_SPINLOCK_H */

arch/x86_64/src/intel64/CMakeLists.txt

@@ -45,6 +45,10 @@ set(SRCS
     intel64_rng.c
     intel64_check_capability.c)
 
+if(CONFIG_ARCH_HAVE_TESTSET)
+  list(APPEND SRCS intel64_testset.S)
+endif()
+
 if(CONFIG_MULTBOOT2_FB_TERM)
   list(APPEND SRCS intel64_mbfb.c)
 endif()

arch/x86_64/src/intel64/Make.defs

@@ -38,6 +38,10 @@ CHIP_ASRCS  = intel64_saveusercontext.S intel64_fullcontextrestore.S intel64_vec
 CHIP_CSRCS  = intel64_start.c intel64_handlers.c intel64_idle.c intel64_lowsetup.c
 CHIP_CSRCS += intel64_serial.c intel64_rng.c intel64_check_capability.c
 
+ifeq ($(CONFIG_ARCH_HAVE_TESTSET), y)
+CHIP_ASRCS += intel64_testset.S
+endif
+
 # Configuration-dependent intel64 files
 
 ifeq ($(CONFIG_MULTBOOT2_FB_TERM),y)

arch/x86_64/src/intel64/intel64_testset.S

@@ -0,0 +1,71 @@
+/****************************************************************************
+ *  arch/x86/src/intel64/intel64_testset.S
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+#include <arch/spinlock.h>
+
+	.file    "intel64_head.S"
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/**************************************************************************
+ * .text
+ **************************************************************************/
+
+	.text
+	.code64
+
+/****************************************************************************
+ * Name: up_testset
+ *
+ * Description:
+ *   Perform an atomic test and set operation on the provided spinlock.
+ *
+ *   This function must be provided via the architecture-specific logic.
+ *
+ * Input Parameters:
+ *   lock  - A reference to the spinlock object.
+ *
+ * Returned Value:
+ *   The spinlock is always locked upon return.  The previous value of the
+ *   spinlock variable is returned, either SP_LOCKED if the spinlock was
+ *   previously locked (meaning that the test-and-set operation failed to
+ *   obtain the lock) or SP_UNLOCKED if the spinlock was previously unlocked
+ *   (meaning that we successfully obtained the lock).
+ *
+ ****************************************************************************/
+
+	.globl   up_testset
+	.type    up_testset, @function
+up_testset:
+	/* Set the value to be written (SP_LOCKED for test-and-set) */
+
+	movq     $SP_LOCKED, %rax
+
+	/* Atomic exchange, the old value is returned in rax */
+
+	xchg    %rax, (%rdi)
+	ret