tfork child call exit after calling fptr.

7d2f082e · Silas Boyd-Wickizer · 6130053e · 7d2f082e
--- a/uthread.S
+++ b/uthread.S
 .globl forkt
 forkt:
-        pushq %rdi      ## new stack ptr
-        pushq %rsi      ## function ptr
-        movq $1, %rdi   ## flag for sys_fork
+        pushq %rdi              ## new stack ptr
+        pushq %rsi              ## function ptr
+        movq $1, %rdi           ## flag for sys_fork
        callq fork
-        popq %rsi
-        popq %rdi
-        cmpl $0, %eax
+        popq %r10               ## function ptr
+        popq %r11               ## new stack ptr
+        cmpl $0, %eax           ## pid/tid
        jne 1f
-        movq %rdi, %rsp
-        jmp *%rsi
+        movq %r11, %rsp
+        andq $(~0xf), %rsp      ## alignment for amd64 ABI
+        movq %rax, %rdi
+        call *%r10
+        call exit
 1:
        ret