kern/amd64: Add spinlock impl for AMD64 port

Signed-off-by: Ian Moffett <ian@osmora.org>

2 files changed, 118 insertions, 0 deletions

diff --git a/sys/arch/amd64/cpu/spinlock.c b/sys/arch/amd64/cpu/spinlock.c
new file mode 100644
index 0000000..8c037a9
--- /dev/null
+++ b/sys/arch/amd64/cpu/spinlock.c
@@ -0,0 +1,67 @@
+/*
+ * Copyright (c) 2025 Ian Marco Moffett and the Osmora Team.
+ * 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 Hyra 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 PURPKERNE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER 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; LKERNS 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
+ * PKERNSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+#include <mu/spinlock.h>
+
+void
+mu_spinlock_acq(volatile size_t *lock, int flags)
+{
+    if (ISSET(flags, SPINLOCK_INTTOG)) {
+        asm volatile("cli");
+    }
+
+    __asmv(
+        "1:\n\t"
+        "   rep; nop\n\t"
+        "   mov $1, %%rax\n\t"
+        "   xchg (%0), %%rax\n\t"
+        "   or %%rax, %%rax\n\t"
+        "   jnz 1b"
+        :
+        : "r" (lock)
+        : "memory", "rax"
+    );
+}
+
+void
+mu_spinlock_rel(volatile size_t *lock, int flags)
+{
+    __asmv(
+        "xor %%rax, %%rax\n\t"
+        "xchg %%rax, %0"
+        : "=m" (*lock)
+        :
+        : "memory", "rax"
+    );
+
+    if (ISSET(flags, SPINLOCK_INTTOG)) {
+        asm volatile("sti");
+    }
+}
diff --git a/sys/inc/mu/spinlock.h b/sys/inc/mu/spinlock.h
new file mode 100644
index 0000000..6795af3
--- /dev/null
+++ b/sys/inc/mu/spinlock.h
@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2025 Ian Marco Moffett and the Osmora Team.
+ * 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 Hyra 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 PURPKERNE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER 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; LKERNS 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
+ * PKERNSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _MU_SPINLOCK_H_
+#define _MU_SPINLOCK_H_ 1
+
+#include <sys/types.h>
+#include <sys/param.h>
+
+/*
+ * Valid spinlock flags
+ */
+#define SPINLOCK_INTTOG BIT(0)      /* interrupts can be toggled */
+
+/*
+ * Acquire a spinlock
+ */
+void mu_spinlock_acq(volatile size_t *lock, int flags);
+
+/*
+ * Release a spinlock
+ */
+void mu_spinlock_rel(volatile size_t *lock, int flags);
+
+#endif  /* !_MU_SPINLOCK_H_ */