kernel: Add support for syscalls

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

3 files changed, 97 insertions, 0 deletions

diff --git a/sys/arch/amd64/amd64/machdep.c b/sys/arch/amd64/amd64/machdep.c
index fa6c1f5..47d6dd0 100644
--- a/sys/arch/amd64/amd64/machdep.c
+++ b/sys/arch/amd64/amd64/machdep.c
@@ -57,6 +57,8 @@ __KERNEL_META("$Hyra$: machdep.c, Ian Marco Moffett, "
 #define INIT_FLAG_IOAPIC 0x00000001U
 #define INIT_FLAG_ACPI   0x00000002U
 
+void syscall_isr(void);
+
 static inline void
 init_tss(struct cpu_info *cur_cpu)
 {
@@ -82,6 +84,7 @@ interrupts_init(void)
     idt_set_desc(0xC, IDT_TRAP_GATE_FLAGS, ISR(ss_fault), 0);
     idt_set_desc(0xD, IDT_TRAP_GATE_FLAGS, ISR(general_prot), 0);
     idt_set_desc(0xE, IDT_TRAP_GATE_FLAGS, ISR(page_fault), 0);
+    idt_set_desc(0x80, IDT_INT_GATE_USER, ISR(syscall_isr), 0);
     idt_load();
 }
 
diff --git a/sys/arch/amd64/amd64/syscall.S b/sys/arch/amd64/amd64/syscall.S
new file mode 100644
index 0000000..fe70523
--- /dev/null
+++ b/sys/arch/amd64/amd64/syscall.S
@@ -0,0 +1,43 @@
+/*
+ * 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/cdefs.h>
+ #include <machine/frameasm.h>
+
+__KERNEL_META "$Hyra$: syscall.S, Ian Marco Moffett, \
+               Syscall ISR code"
+
+.text
+.globl syscall_isr
+syscall_isr:
+    push_trapframe $0
+    mov %rsp, %rdi
+    call __syscall
+    pop_trapframe
+    iretq
diff --git a/sys/arch/amd64/amd64/syscall.c b/sys/arch/amd64/amd64/syscall.c
new file mode 100644
index 0000000..9b1f988
--- /dev/null
+++ b/sys/arch/amd64/amd64/syscall.c
@@ -0,0 +1,51 @@
+/*
+ * 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/syscall.h>
+
+void
+__syscall(struct trapframe *tf)
+{
+    struct syscall_args args = {
+        .code = tf->rax,
+        .arg0 = tf->rdi,
+        .arg1 = tf->rsi,
+        .arg2 = tf->rcx,
+        .arg3 = tf->r8,
+        .arg4 = tf->r9,
+        .sp = tf->rsp,
+        .ret = tf->rax,
+    };
+
+    if (args.code < __MAX_SYSCALLS) {
+        g_syscall_table[tf->rax](&args);
+    }
+
+    tf->rax = args.ret;
+}