kern/amd64+mu: Add processor descriptor + percpu state

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

4 files changed, 148 insertions, 0 deletions

diff --git a/sys/arch/amd64/cpu/cpu.c b/sys/arch/amd64/cpu/cpu.c
new file mode 100644
index 0000000..942f5b3
--- /dev/null
+++ b/sys/arch/amd64/cpu/cpu.c
@@ -0,0 +1,52 @@
+/*
+ * 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/types.h>
+#include <sys/cdefs.h>
+#include <os/trace.h>
+#include <mu/cpu.h>
+#include <md/msr.h>
+
+struct cpu_info *
+cpu_self(void)
+{
+    /*
+     * We aren't gonna do what the fuck kinda pointer
+     * bendover backwards until your back breaks kinda
+     * shit BSD does with its weird offsetof shit, just
+     * read the damn MSR...
+     */
+    return (void *)rdmsr(IA32_GS_BASE);
+}
+
+void
+cpu_conf(struct cpu_info *ci)
+{
+    wrmsr(IA32_GS_BASE, (uintptr_t)ci);
+}
diff --git a/sys/inc/kern/cpu.h b/sys/inc/kern/cpu.h
new file mode 100644
index 0000000..dfd0c34
--- /dev/null
+++ b/sys/inc/kern/cpu.h
@@ -0,0 +1,46 @@
+/*
+ * 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 _KERN_CPU_H_
+#define _KERN_CPU_H_ 1
+
+#include <sys/types.h>
+
+/*
+ * Processor descriptor
+ *
+ * @id: Logical ID of the processor
+ * @self: Self pointer for referencing via %GS
+ */
+struct cpu_info {
+    uint8_t id;
+    struct cpu_info *self;
+};
+
+#endif  /* !_KERN_CPU_H_ */
diff --git a/sys/inc/mu/cpu.h b/sys/inc/mu/cpu.h
new file mode 100644
index 0000000..fb7aade
--- /dev/null
+++ b/sys/inc/mu/cpu.h
@@ -0,0 +1,47 @@
+/*
+ * 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_CPU_H_
+#define _MU_CPU_H_ 1
+
+#include <sys/types.h>
+#include <kern/cpu.h>
+
+/*
+ * Get a reference to the processor descriptor
+ * for the current core
+ */
+struct cpu_info *cpu_self(void);
+
+/*
+ * Configure a processor core
+ */
+void cpu_conf(struct cpu_info *ci);
+
+#endif  /* !_MU_CPU_H_ */
diff --git a/sys/kern/kern_init.c b/sys/kern/kern_init.c
index 2c6e357..dbe3af0 100644
--- a/sys/kern/kern_init.c
+++ b/sys/kern/kern_init.c
@@ -31,9 +31,11 @@
 #include <dev/cons/cons.h>
 #include <os/trace.h>
 #include <acpi/acpi.h>
+#include <mu/cpu.h>
 #include <vm/phys.h>
 #include <vm/vm.h>
 
+struct cpu_info g_bsp;
 struct console g_bootcons;
 void kmain(void);
 
@@ -45,4 +47,5 @@ kmain(void)
     vm_phys_init();
     vm_init();
     acpi_init();
+    cpu_conf(&g_bsp);
 }