From 9edd65c48ee75751327c6ee6d42a7009e726d667 Mon Sep 17 00:00:00 2001
From: Kimplul <kimi.h.kuparinen@gmail.com>
Date: Thu, 10 Nov 2022 15:14:10 +0200
Subject: initial implementation of process copying

+ Not actually working (at least fully), need to continue debugging when
  I have time.
---
 arch/riscv64/conf/init   | Bin 2144 -> 2560 bytes
 arch/riscv64/conf/init.c |  32 ++++++++++++++++++++++++++++++++
 arch/riscv64/conf/initrd | Bin 2560 -> 3072 bytes
 3 files changed, 32 insertions(+)

(limited to 'arch/riscv64')

diff --git a/arch/riscv64/conf/init b/arch/riscv64/conf/init
index b75076f..47e733f 100755
Binary files a/arch/riscv64/conf/init and b/arch/riscv64/conf/init differ
diff --git a/arch/riscv64/conf/init.c b/arch/riscv64/conf/init.c
index feb5177..1886760 100644
--- a/arch/riscv64/conf/init.c
+++ b/arch/riscv64/conf/init.c
@@ -88,6 +88,26 @@ static void print_value(const char *s, uint64_t v)
 	sys_putch('\n');
 }
 
+static uint64_t sys_fork()
+{
+	long register a0 asm ("a0") = SYS_FORK;
+	long register a1 asm ("a1") = 0;
+	ecall();
+	if (a0 != 0)
+		print_value("fork() failed with error ", a0);
+	return a1;
+}
+
+static uint64_t sys_swap(long tid)
+{
+	long register a0 asm ("a0") = SYS_SWAP;
+	long register a1 asm ("a1") = tid;
+	ecall();
+	if (a0 != 0)
+		print_value("swap() failed with error ", a0);
+	return a0;
+}
+
 void _start()
 {
 	sys_noop();
@@ -107,4 +127,16 @@ void _start()
 
 	print_value("End ticks", i);
 	print_value("Syscalls per second", n);
+
+	puts("Starting fork():\n");
+	long pid = sys_fork();
+	if (pid != 0) {
+		print_value("Child pid: ", pid);
+		puts("Swapping to child...\n");
+		sys_swap(pid);
+		puts("We shouldn't be here?\n");
+		while(1);
+	}
+
+	puts("Hello from child!\n");
 }
diff --git a/arch/riscv64/conf/initrd b/arch/riscv64/conf/initrd
index 3af4d2e..24f9fb4 100644
Binary files a/arch/riscv64/conf/initrd and b/arch/riscv64/conf/initrd differ
-- 
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