From fa4b8f84383ae197e643a46c36bf58ab8dffc95c Mon Sep 17 00:00:00 2001 From: Brian Gerst Date: Wed, 9 Dec 2009 12:34:41 -0500 Subject: [PATCH] x86, 64-bit: Use user_mode() to determine new stack pointer in copy_thread() Use user_mode() instead of a magic value for sp to determine when returning to kernel mode. Signed-off-by: Brian Gerst LKML-Reference: <1260380084-3707-3-git-send-email-brgerst@gmail.com> Signed-off-by: H. Peter Anvin --- arch/x86/kernel/process_64.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 92484c2..00ac66f 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -254,7 +254,7 @@ int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags) regs.flags = X86_EFLAGS_IF; /* Ok, create the new process.. */ - return do_fork(flags | CLONE_VM | CLONE_UNTRACED, ~0UL, ®s, 0, NULL, NULL); + return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s, 0, NULL, NULL); } EXPORT_SYMBOL(kernel_thread); @@ -312,8 +312,9 @@ int copy_thread(unsigned long clone_flags, unsigned long sp, *childregs = *regs; childregs->ax = 0; - childregs->sp = sp; - if (sp == ~0UL) + if (user_mode(regs)) + childregs->sp = sp; + else childregs->sp = (unsigned long)childregs; p->thread.sp = (unsigned long) childregs; -- 2.7.4