From 8e268df60bde6b5548b849cc9b83a224a74b3e43 Mon Sep 17 00:00:00 2001
From: Ian Moffett <ian@osmora.org>
Date: Wed, 17 Sep 2025 19:21:57 -0400
Subject: kern: Add syscall entry and SYS_exit syscall

Signed-off-by: Ian Moffett <ian@osmora.org>
---
 src/sys/arch/amd64/cpu/cpu_conf.c |  3 +++
 src/sys/arch/amd64/cpu/trap.S     |  6 ++++++
 src/sys/arch/amd64/cpu/trap.c     | 19 +++++++++++++++++++
 3 files changed, 28 insertions(+)

(limited to 'src/sys/arch')

diff --git a/src/sys/arch/amd64/cpu/cpu_conf.c b/src/sys/arch/amd64/cpu/cpu_conf.c
index e462ef3..531f53b 100644
--- a/src/sys/arch/amd64/cpu/cpu_conf.c
+++ b/src/sys/arch/amd64/cpu/cpu_conf.c
@@ -36,6 +36,8 @@
 #include <machine/gdt.h>
 #include <string.h>
 
+extern void syscall_isr(void);
+
 /*
  * Initialize interrupt vectors
  */
@@ -54,6 +56,7 @@ init_vectors(void)
     idt_set_desc(0xC, IDT_TRAP_GATE, ISR(ss_fault), 0);
     idt_set_desc(0xD, IDT_TRAP_GATE, ISR(general_prot), 0);
     idt_set_desc(0xE, IDT_TRAP_GATE, ISR(page_fault), 0);
+    idt_set_desc(0x80, IDT_USER_GATE, ISR(syscall_isr), 0);
 }
 
 void
diff --git a/src/sys/arch/amd64/cpu/trap.S b/src/sys/arch/amd64/cpu/trap.S
index ef5c14f..6e4d58c 100644
--- a/src/sys/arch/amd64/cpu/trap.S
+++ b/src/sys/arch/amd64/cpu/trap.S
@@ -107,3 +107,9 @@ INTR_ENTRY(lapic_tmr_isr)
     mov %rsp, %rdi
     call md_sched_switch
 INTR_EXIT(lapic_tmr_isr)
+
+    .global syscall_isr
+INTR_ENTRY(syscall_isr)
+    mov %rsp, %rdi
+    call trap_syscall
+INTR_EXIT(syscall_isr)
diff --git a/src/sys/arch/amd64/cpu/trap.c b/src/sys/arch/amd64/cpu/trap.c
index 046263b..6ddc079 100644
--- a/src/sys/arch/amd64/cpu/trap.c
+++ b/src/sys/arch/amd64/cpu/trap.c
@@ -36,6 +36,7 @@
 #include <sys/cdefs.h>
 #include <sys/panic.h>
 #include <sys/syslog.h>
+#include <sys/syscall.h>
 #include <machine/trap.h>
 
 /*
@@ -145,6 +146,24 @@ trapframe_dump(struct trapframe *tf)
         tf->rbp, tf->rsp, tf->rip);
 }
 
+void
+trap_syscall(struct trapframe *tf)
+{
+    struct syscall_args scargs = {
+        .arg[0] = tf->rdi,
+        .arg[1] = tf->rsi,
+        .arg[2] = tf->rdx,
+        .arg[3] = tf->r10,
+        .arg[4] = tf->r9,
+        .arg[5] = tf->r8,
+        .tf = tf
+    };
+
+    if (tf->rax < MAX_SYSCALLS && tf->rax > 0) {
+        tf->rax = g_sctab[tf->rax](&scargs);
+    }
+}
+
 void
 trap_handler(struct trapframe *tf)
 {
-- 
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