overhaul clone syscall wrapping

[musl] / src / thread / x86_64 / clone.s

diff --git a/src/thread/x86_64/clone.s b/src/thread/x86_64/clone.s
index bf128a4..4db081c 100644 (file)
--- a/src/thread/x86_64/clone.s
+++ b/src/thread/x86_64/clone.s
@@ -1,21 +1,30 @@
-/* Copyright 2011 Nicholas J. Kain, licensed GNU LGPL 2.1 or later */
 .text
-.global __uniclone
-.type   __uniclone,@function
-/* rdi = child_stack, rsi = start, rdx = pthread_struct */
-__uniclone:
-        subq    $8,%rsp         /* pad parent stack to prevent branch later */
-        subq    $24,%rdi        /* grow child_stack */
-        mov     %rsi,8(%rdi)    /* push start onto child_stack as return ptr */
-        mov     %rdx,0(%rdi)    /* push pthread_struct onto child_stack */
-        mov     %rdx,%r8        /* r8 = tls */
-        mov     %rdi,%rsi       /* rsi = child_stack */
-        leaq    40(%rdx),%r10   /* r10 = child_id */
-        movl    $56,%eax        /* clone syscall number */
-        movl    $0x7d0f00,%edi  /* rdi = flags */
-        mov     %r10,%rdx       /* rdx = parent_id */
-        syscall                 /* clone(flags, child_stack, parent_id,
-                                 *       child_id, tls) */
-        pop     %rdi            /* child stack: restore pthread_struct
-                                 * parent stack: undo rsp displacement */
-        ret
+.global __clone
+.weak clone
+.type   __clone,@function
+.type   clone,@function
+__clone:
+clone:
+       xor %eax,%eax
+       mov $56,%al
+       mov %rdi,%r11
+       mov %rdx,%rdi
+       mov %r8,%rdx
+       mov %r9,%r8
+       mov 8(%rsp),%r10
+       mov %r11,%r9
+       and $-16,%rsi
+       sub $8,%rsi
+       mov %rcx,(%rsi)
+       syscall
+       test %eax,%eax
+       jnz 1f
+       xor %ebp,%ebp
+       pop %rdi
+       call *%r9
+       mov %eax,%edi
+       xor %eax,%eax
+       mov $60,%al
+       syscall
+       hlt
+1:     ret