* [musl] A question about the __clone() within __NR_clone3 syscall in LoongArch.
@ 2022-11-07 2:07 王洪亮
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From: 王洪亮 @ 2022-11-07 2:07 UTC (permalink / raw)
To: musl
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Hi, Rich
I found theclone3_stack_valid() in latest kernel, the condition of
(kargs->stack_size == 0) is still valid,
so the __clone() (within __NR_clone3 syscall ) is still fail.
we still implement __clone() within __NR_clone3 syscall in LoongArch ?
diff --git a/src/thread/loongarch64/clone.s
b/src/thread/loongarch64/clone.s
new file mode 100644
index 00000000..86e69cfa
--- /dev/null
+++ b/src/thread/loongarch64/clone.s
@@ -0,0 +1,47 @@
+#__clone(func, stack, flags, arg, ptid, tls, ctid)
+# a0, a1, a2, a3, a4, a5, a6
+# sys_clone3(struct clone_args *cl_args, size_t size)
+# a0 a1
+
+.global __clone
+.hidden __clone
+.type __clone,@function
+__clone:
+ # Save function pointer and argument pointer on new thread stack
+ addi.d $a1, $a1, -16
+ st.d $a0, $a1, 0 # save function pointer
+ st.d $a3, $a1, 8 # save argument pointer
+
+ li.d $t0, ~0x004000ff # mask CSIGNAL and CLONE_DETACHED
+ and $t1, $a2, $t0 # cl_args.flags
+ li.d $t0, 0x000000ff # CSIGNAL
+ and $t2, $a2, $t0 # cl_args.exit_signal
+
+ bstrins.d $sp, $zero, 3, 0 # align stack to 16 bytes
+ addi.d $sp, $sp, -88 # struct clone_args
+ st.d $t1, $sp, 0 # flags
+ st.d $a4, $sp, 8 # pidfd
+ st.d $a6, $sp, 16 # child_tid
+ st.d $a4, $sp, 24 # parent_tid
+ st.d $t2, $sp, 32 # exit_signal
+ st.d $a1, $sp, 40 # stack
+ st.d $zero, $sp, 48 # stack_size
+ st.d $a5, $sp, 56 # tls
+ st.d $zero, $sp, 64 # set_tid
+ st.d $zero, $sp, 72 # set_tid_size
+ st.d $zero, $sp, 80 # cgroup
+
+ move $a0, $sp
+ li.d $a1, 88
+ li.d $a7, 435 # __NR_clone3
+ syscall 0 # call clone3
+
+ beqz $a0, 1f # whether child process
+ addi.d $sp, $sp, 88
+ jr $ra # parent process return
+1:
+ ld.d $t8, $sp, 0 # function pointer
+ ld.d $a0, $sp, 8 # argument pointer
+ jirl $ra, $t8, 0 # call the user's function
+ li.d $a7, 93
+ syscall 0 # child process exit
Do we still want to implement clone functionality entirely with clone3,
given the
previous conclusion of keeping clone(2) for existing sandboxes to
continue to work?
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2022-11-07 2:07 [musl] A question about the __clone() within __NR_clone3 syscall in LoongArch 王洪亮
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