Add patch to modify clone wrapper.

This patches substitutes the syscalls in the clone wrapper
with normal function calls.

Signed-off-by: Robert Kuban <robert.kuban@opensynergy.com>
Reviewed-by: Eduard Vintilă <eduard.vintila47@gmail.com>
Reviewed-by: Razvan Virtan <virtanrazvan@gmail.com>
Reviewed-by: Razvan Deaconescu <razvand@unikraft.io>
Approved-by: Razvan Deaconescu <razvand@unikraft.io>
Tested-by: Unikraft CI <monkey@unikraft.io>
GitHub-Closes: #6

diff --git a/patches/0019-Modify-clone-wrapper.patch b/patches/0019-Modify-clone-wrapper.patch
new file mode 100644 (file)
index 0000000..a4af6db
--- /dev/null
+++ b/patches/0019-Modify-clone-wrapper.patch
@@ -0,0 +1,61 @@
+From 2ad50560ffad11f6bc1c7788ae733760f6d85f7f Mon Sep 17 00:00:00 2001
+From: Robert Kuban <robert.kuban@opensynergy.com>
+Date: Thu, 11 Aug 2022 18:03:23 +0200
+Subject: [PATCH] Modify clone wrapper
+
+Signed-off-by: Robert Kuban <robert.kuban@opensynergy.com>
+---
+ src/thread/aarch64/clone.s | 24 ++++++++++++++++--------
+ 1 file changed, 16 insertions(+), 8 deletions(-)
+
+diff --git a/src/thread/aarch64/clone.s b/src/thread/aarch64/clone.s
+index 50af913c..cd1f956b 100644
+--- a/src/thread/aarch64/clone.s
++++ b/src/thread/aarch64/clone.s
+@@ -1,12 +1,19 @@
+ // __clone(func, stack, flags, arg, ptid, tls, ctid)
+ //         x0,   x1,    w2,    x3,  x4,   x5,  x6
+ 
+-// syscall(SYS_clone, flags, stack, ptid, tls, ctid)
+-//         x8,        x0,    x1,    x2,   x3,  x4
++// see: lib/posix-process/clone.c
++// uk_syscall_r_clone(flags, stack, ptid, tlsp, ctid)
++//                    x0,    x1,    x2,   x3,   x4
++
++// see: lib/posix-process/process.c
++// uk_syscall_r_exit(status)
++//                   x0
+ 
+ .global __clone
+ .type   __clone,%function
+ __clone:
++      stp x29, x30, [sp, #-16]!
++
+       // align stack and save func,arg
+       and x1,x1,#-16
+       stp x0,x3,[x1,#-16]!
+@@ -16,14 +23,15 @@ __clone:
+       mov x2,x4
+       mov x3,x5
+       mov x4,x6
+-      mov x8,#220 // SYS_clone
+-      svc #0
++      bl uk_syscall_r_clone
+ 
+       cbz x0,1f
+       // parent
++      ldp x29, x30, [sp], #16
+       ret
+-      // child
++      // child (SP is X1 from syscall now)
+ 1:    ldp x1,x0,[sp],#16
+-      blr x1
+-      mov x8,#93 // SYS_exit
+-      svc #0
++      blr x1 // call func(arg)
++      mov x0, xzr
++      bl uk_syscall_r_exit
++      wfi
+-- 
+2.25.1
+