x86: split ret_from_fork
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 69babd8..5526d17 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -450,7 +450,7 @@
RESTORE_REST
testl $3, CS-ARGOFFSET(%rsp) # from kernel_thread?
- jz retint_restore_args
+ jz 1f
testl $_TIF_IA32, TI_flags(%rcx) # 32-bit compat task needs IRET
jnz int_ret_from_sys_call
@@ -458,6 +458,16 @@
RESTORE_TOP_OF_STACK %rdi, -ARGOFFSET
jmp ret_from_sys_call # go to the SYSRET fastpath
+1:
+ subq $REST_SKIP, %rsp # move the stack pointer back
+ CFI_ADJUST_CFA_OFFSET REST_SKIP
+ movq %rbp, %rdi
+ call *%rbx
+ # exit
+ mov %eax, %edi
+ call do_exit
+ ud2 # padding for call trace
+
CFI_ENDPROC
END(ret_from_fork)
@@ -1206,21 +1216,6 @@
jmp 2b
.previous
-ENTRY(kernel_thread_helper)
- pushq $0 # fake return address
- CFI_STARTPROC
- /*
- * Here we are in the child and the registers are set as they were
- * at kernel_thread() invocation in the parent.
- */
- call *%rsi
- # exit
- mov %eax, %edi
- call do_exit
- ud2 # padding for call trace
- CFI_ENDPROC
-END(kernel_thread_helper)
-
/*
* execve(). This function needs to use IRET, not SYSRET, to set up all state properly.
*