From f166b2303a96a5e65e235139291df93b2b24bc3e Mon Sep 17 00:00:00 2001
From: Ian Moffett <ian@osmora.org>
Date: Sat, 16 Mar 2024 13:03:19 -0400
Subject: kernel,libc: syscall: Improve syscall code

- Remove the SYS_debug syscall
- First syscall starts at 1

Signed-off-by: Ian Moffett <ian@osmora.org>
---
 lib/libc/include/sys/syscall.h | 1 -
 sys/arch/amd64/amd64/syscall.c | 5 +++--
 sys/include/sys/syscall.h      | 3 +--
 sys/kern/kern_syscall.c        | 8 --------
 4 files changed, 4 insertions(+), 13 deletions(-)

diff --git a/lib/libc/include/sys/syscall.h b/lib/libc/include/sys/syscall.h
index b5e5fc2..34f762d 100644
--- a/lib/libc/include/sys/syscall.h
+++ b/lib/libc/include/sys/syscall.h
@@ -34,7 +34,6 @@
 #include <stdint.h>
 #endif
 
-#define SYS_debug 0
 #define SYS_exit  1
 
 #if !defined(__ASSEMBLER__)
diff --git a/sys/arch/amd64/amd64/syscall.c b/sys/arch/amd64/amd64/syscall.c
index e80fe94..68235d5 100644
--- a/sys/arch/amd64/amd64/syscall.c
+++ b/sys/arch/amd64/amd64/syscall.c
@@ -42,7 +42,8 @@ __syscall(struct trapframe *tf)
         .sp = tf->rsp
     };
 
-    if (args.code < __MAX_SYSCALLS) {
-        tf->rax = g_syscall_table[tf->rax](&args);
+    if (args.code < __MAX_SYSCALLS && args.code > 0) {
+        args.code -= 1;
+        tf->rax = g_syscall_table[args.code](&args);
     }
 }
diff --git a/sys/include/sys/syscall.h b/sys/include/sys/syscall.h
index 03eda0b..66dc5f3 100644
--- a/sys/include/sys/syscall.h
+++ b/sys/include/sys/syscall.h
@@ -37,8 +37,7 @@
 
 /* Do not reorder */
 enum {
-    SYS_debug = 0,
-    SYS_exit,
+    SYS_exit = 1,
     __MAX_SYSCALLS
 };
 
diff --git a/sys/kern/kern_syscall.c b/sys/kern/kern_syscall.c
index 5a88bbb..b6e31d1 100644
--- a/sys/kern/kern_syscall.c
+++ b/sys/kern/kern_syscall.c
@@ -32,13 +32,6 @@
 #include <sys/cdefs.h>
 #include <sys/types.h>
 
-static uint64_t
-sys_debug(struct syscall_args *args)
-{
-    /* TODO */
-    return 0;
-}
-
 __noreturn static uint64_t
 sys_exit(struct syscall_args *args)
 {
@@ -47,6 +40,5 @@ sys_exit(struct syscall_args *args)
 }
 
 uint64_t(*g_syscall_table[__MAX_SYSCALLS])(struct syscall_args *args) = {
-    sys_debug,
     sys_exit,
 };
-- 
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