kernel/amd64: Prepare for scheduler

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

9 files changed, 359 insertions, 0 deletions

diff --git a/sys/arch/amd64/amd64/lapic_intr.S b/sys/arch/amd64/amd64/lapic_intr.S
index 295de2d..a3fa7e4 100644
--- a/sys/arch/amd64/amd64/lapic_intr.S
+++ b/sys/arch/amd64/amd64/lapic_intr.S
@@ -5,5 +5,7 @@
 lapic_tmr_isr:
     push_trapframe $0
     mov %rsp, %rdi
+    call sched_switch
+    call lapic_eoi
     pop_trapframe
     iretq
diff --git a/sys/arch/amd64/amd64/mp.c b/sys/arch/amd64/amd64/mp.c
new file mode 100644
index 0000000..9512aa6
--- /dev/null
+++ b/sys/arch/amd64/amd64/mp.c
@@ -0,0 +1,93 @@
+/*
+ * Copyright (c) 2023-2024 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 PURPOSE
+ * 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; 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.
+ */
+
+#include <sys/types.h>
+#include <sys/limine.h>
+#include <sys/syslog.h>
+#include <sys/spinlock.h>
+#include <sys/sched.h>
+#include <machine/cpu.h>
+#include <vm/dynalloc.h>
+#include <assert.h>
+#include <string.h>
+
+#define pr_trace(fmt, ...) kprintf("cpu_mp: " fmt, ##__VA_ARGS__)
+
+static volatile struct limine_smp_request g_smp_req = {
+    .id = LIMINE_SMP_REQUEST,
+    .revision = 0
+};
+
+static void
+ap_trampoline(struct limine_smp_info *si)
+{
+    struct spinlock lock = {0};
+    struct cpu_info *ci;
+
+    spinlock_acquire(&lock);
+    ci = dynalloc(sizeof(*ci));
+    __assert(ci != NULL);
+
+    memset(ci, 0, sizeof(*ci));
+    cpu_startup(ci);
+
+    spinlock_release(&lock);
+    sched_enter();
+
+    while (1);
+}
+
+void
+mp_bootstrap_aps(struct cpu_info *ci)
+{
+    struct limine_smp_response *resp = g_smp_req.response;
+    struct limine_smp_info **cpus;
+    size_t cpu_init_counter;
+
+    /* Should not happen */
+    __assert(resp != NULL);
+
+    cpus = resp->cpus;
+    cpu_init_counter = resp->cpu_count - 1;
+
+    if (resp->cpu_count == 1) {
+        pr_trace("CPU has 1 core, no APs to bootstrap...\n");
+        return;
+    }
+
+    pr_trace("Bootstrapping %d cores...\n", cpu_init_counter);
+    for (size_t i = 0; i < resp->cpu_count; ++i) {
+        if (ci->apicid == cpus[i]->lapic_id) {
+            pr_trace("Skip %d (BSP)... continue\n", ci->apicid);
+            continue;
+        }
+
+        cpus[i]->goto_address = ap_trampoline;
+    }
+}
diff --git a/sys/arch/amd64/conf/GENERIC b/sys/arch/amd64/conf/GENERIC
index ea6ba76..a7bbc81 100644
--- a/sys/arch/amd64/conf/GENERIC
+++ b/sys/arch/amd64/conf/GENERIC
@@ -1,2 +1,5 @@
 // Kernel options
 option SPECTRE_IBRS no
+
+// Kernel constants
+setval SCHED_NQUEUE 4
diff --git a/sys/include/arch/amd64/cpu.h b/sys/include/arch/amd64/cpu.h
index 84391ba..b5420a6 100644
--- a/sys/include/arch/amd64/cpu.h
+++ b/sys/include/arch/amd64/cpu.h
@@ -32,6 +32,7 @@
 
 #include <sys/types.h>
 #include <sys/cdefs.h>
+#include <sys/proc.h>
 #include <machine/tss.h>
 
 struct cpu_info {
@@ -39,10 +40,13 @@ struct cpu_info {
     uint8_t has_x2apic : 1;
     size_t lapic_tmr_freq;
     struct tss_entry *tss;
+    struct proc *curtd;
 };
 
 void cpu_startup(struct cpu_info *ci);
 struct cpu_info *this_cpu(void);
+void mp_bootstrap_aps(struct cpu_info *ci);
+
 extern struct cpu_info g_bsp_ci;
 
 #endif  /* !_MACHINE_CPU_H_ */
diff --git a/sys/include/sys/proc.h b/sys/include/sys/proc.h
new file mode 100644
index 0000000..ba47a5c
--- /dev/null
+++ b/sys/include/sys/proc.h
@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2023-2024 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 PURPOSE
+ * 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; 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.
+ */
+
+#ifndef _SYS_PROC_H_
+#define _SYS_PROC_H_
+
+#include <sys/types.h>
+#include <sys/spinlock.h>
+#if defined(_KERNEL)
+#include <machine/cpu.h>
+#include <machine/frame.h>
+#endif  /* _KERNEL */
+
+#if defined(_KERNEL)
+
+struct proc {
+    pid_t pid;
+    struct cpu_info *cpu;
+};
+
+#endif  /* _KERNEL */
+#endif  /* !_SYS_PROC_H_ */
diff --git a/sys/include/sys/sched.h b/sys/include/sys/sched.h
new file mode 100644
index 0000000..33d546d
--- /dev/null
+++ b/sys/include/sys/sched.h
@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2023-2024 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 PURPOSE
+ * 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; 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.
+ */
+
+#ifndef _SYS_SCHED_H_
+#define _SYS_SCHED_H_
+
+#if defined(_KERNEL)
+
+void sched_init(void);
+void sched_enter(void);
+
+#endif  /* _KERNEL */
+#endif  /* !_SYS_SCHED_H_ */
diff --git a/sys/include/sys/schedvar.h b/sys/include/sys/schedvar.h
new file mode 100644
index 0000000..00caeb4
--- /dev/null
+++ b/sys/include/sys/schedvar.h
@@ -0,0 +1,63 @@
+/*
+ * Copyright (c) 2023-2024 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 PURPOSE
+ * 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; 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.
+ */
+
+#ifndef _SYS_SCHEDVAR_H_
+#define _SYS_SCHEDVAR_H_
+
+#include <sys/cdefs.h>
+#include <sys/queue.h>
+#include <sys/proc.h>
+
+#if defined(_KERNEL)
+#define DEFAULT_TIMESLICE_USEC 1050
+#define SHORT_TIMESLICE_USEC 10
+
+#define SCHED_POLICY_MLFQ 0x00U   /* Multilevel feedback queue */
+#define SCHED_POLICY_RR   0x01U   /* Round robin */
+
+typedef uint8_t sched_policy_t;
+
+/* Might be set by kconf(1) */
+#if defined(__SCHED_NQUEUE)
+#define SCHED_NQUEUE __SCHED_NQUEUE
+#else
+#define SCHED_NQUEUE 4
+#endif  /* __SCHED_NQUEUE */
+
+/* Ensure SCHED_NQUEUE is an acceptable value */
+__static_assert(SCHED_NQUEUE <= 8, "SCHED_NQUEUE exceeds max");
+__static_assert(SCHED_NQUEUE > 0, "SCHED_NQUEUE cannot be zero");
+
+struct sched_queue {
+    TAILQ_HEAD(, proc) q;
+    size_t nthread;
+};
+
+#endif  /* _KERNEL */
+#endif  /* !_SYS_SCHEDVAR_H_ */
diff --git a/sys/kern/init_main.c b/sys/kern/init_main.c
index 94fa8c0..6018dfe 100644
--- a/sys/kern/init_main.c
+++ b/sys/kern/init_main.c
@@ -29,6 +29,7 @@
 
 #include <sys/reboot.h>
 #include <sys/syslog.h>
+#include <sys/sched.h>
 #include <dev/cons/cons.h>
 #include <dev/acpi/acpi.h>
 #include <machine/cpu.h>
@@ -51,6 +52,10 @@ main(void)
     /* Startup the BSP */
     cpu_startup(&g_bsp_ci);
 
+    /* Start scheduler and bootstrap APs */
+    sched_init();
+    mp_bootstrap_aps(&g_bsp_ci);
+
     /* Nothing left to do... halt */
     cpu_reboot(REBOOT_HALT);
     __builtin_unreachable();
diff --git a/sys/kern/kern_sched.c b/sys/kern/kern_sched.c
new file mode 100644
index 0000000..b79d682
--- /dev/null
+++ b/sys/kern/kern_sched.c
@@ -0,0 +1,102 @@
+/*
+ * Copyright (c) 2023-2024 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 PURPOSE
+ * 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; 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.
+ */
+
+#include <sys/types.h>
+#include <sys/sched.h>
+#include <sys/schedvar.h>
+#include <sys/cdefs.h>
+#include <sys/syslog.h>
+#include <machine/frame.h>
+#include <dev/timer.h>
+#include <assert.h>
+
+#define pr_trace(fmt, ...) kprintf("ksched: " fmt, ##__VA_ARGS__)
+
+void sched_switch(struct trapframe *tf);
+
+static sched_policy_t policy = SCHED_POLICY_RR;
+
+/*
+ * Thread ready queues - all threads ready to be
+ * scheduled should be added to the toplevel queue.
+ */
+static struct sched_queue qlist[SCHED_NQUEUE];
+
+/*
+ * Perform timer oneshot
+ */
+static inline void
+sched_oneshot(bool now)
+{
+    struct timer timer;
+    size_t usec = now ? SHORT_TIMESLICE_USEC : DEFAULT_TIMESLICE_USEC;
+    tmrr_status_t tmr_status;
+
+    tmr_status = req_timer(TIMER_SCHED, &timer);
+    __assert(tmr_status == TMRR_SUCCESS);
+
+    timer.oneshot_us(usec);
+}
+
+/*
+ * Perform a context switch.
+ *
+ * TODO
+ */
+void
+sched_switch(struct trapframe *tf)
+{
+    static struct spinlock lock = {0};
+
+    spinlock_acquire(&lock);
+    spinlock_release(&lock);
+    sched_oneshot(false);
+}
+
+/*
+ * Main scheduler loop
+ */
+void
+sched_enter(void)
+{
+    sched_oneshot(false);
+    for (;;);
+}
+
+void
+sched_init(void)
+{
+    /* Setup the queues */
+    for (int i = 0; i < SCHED_NQUEUE; ++i) {
+        TAILQ_INIT(&qlist[i].q);
+    }
+
+    pr_trace("Prepared %d queues (policy=0x%x)\n",
+        SCHED_NQUEUE, policy);
+}