From 5763f003a53ddaa63655058f19d9fe662751592d Mon Sep 17 00:00:00 2001
From: Pedro Falcato <pedro.falcato@gmail.com>
Date: Thu, 9 Feb 2023 16:34:12 +0000
Subject: riscv64: add vfork

Implement vfork() using clone(CLONE_VM | CLONE_VFORK | ...).
---
 src/process/riscv64/vfork.s | 12 ++++++++++++
 1 file changed, 12 insertions(+)
 create mode 100644 src/process/riscv64/vfork.s

diff --git a/src/process/riscv64/vfork.s b/src/process/riscv64/vfork.s
new file mode 100644
index 00000000..c93dca23
--- /dev/null
+++ b/src/process/riscv64/vfork.s
@@ -0,0 +1,12 @@
+.global vfork
+.type vfork,@function
+vfork:
+	/* riscv does not have SYS_vfork, so we must use clone instead */
+	/* note: riscv's clone = clone(flags, sp, ptidptr, tls, ctidptr) */
+	li a7, 220
+	li a0, 0x100 | 0x4000 | 17 /* flags = CLONE_VM | CLONE_VFORK | SIGCHLD */
+	mv a1, sp
+	/* the other arguments are ignoreable */
+	ecall
+	.hidden __syscall_ret
+	j __syscall_ret
-- 
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