--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/user/matac42/xv6-add-call.md	Mon Sep 20 00:10:04 2021 +0900
@@ -0,0 +1,107 @@
+# xv6にsystem callを追加する
+
+参考:
+https://www.geeksforgeeks.org/xv6-operating-system-adding-a-new-system-call/
+
+### syscall.cのsyscalls[]に追記
+```
+[SYS_hoge] sys_hoge,
+```
+
+### syscall.cにexternを追記
+```
+extern uint64 sys_hoge(void);
+```
+
+### syscall.hに追記
+```
+#define SYS_hoge 22
+```
+
+### sysproc.cに実装を追記
+```
+uint64 sys_hoge(void)
+{
+  return 1;
+}
+```
+
+### user.hに追記
+```
+int hoge(void);
+```
+
+### usys.plに追記
+```
+entry("hoge");
+```
+
+### rebuild & run
+
+```
+$make clean
+$make qemu
+```
+
+if docker-compose
+
+```
+$docker-compose down
+$docker-compose build
+$docker-compose run --name xv6 xv6
+```
+
+# xv6にuser programを追加する
+
+参考:
+https://www.geeksforgeeks.org/xv6-operating-system-add-a-user-program/
+
+### user/hoge.c(プログラム例)
+```c
+#include "kernel/types.h"
+#include "kernel/stat.h"
+#include "user/user.h"
+    
+int main(int argc, char *argv[])
+{
+  fprintf(1, "hogehoge\n");
+  exit(0);
+}
+```
+
+### MakefileのUPROGSに`$U/_hoge\`を追記
+```
+UPROGS=\
+	$U/_cat\
+	$U/_echo\
+	$U/_forktest\
+	$U/_grep\
+	$U/_init\
+	$U/_kill\
+	$U/_ln\
+	$U/_ls\
+	$U/_mkdir\
+	$U/_rm\
+	$U/_sh\
+	$U/_stressfs\
+	$U/_usertests\
+	$U/_grind\
+	$U/_wc\
+	$U/_zombie\
+	$U/_hoge\
+```
+
+### rebuild & run
+
+```
+$make clean
+$make qemu
+```
+
+if docker-compose
+
+```
+$docker-compose down
+$docker-compose build
+$docker-compose run --name xv6 xv6
+```
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