On Wed, Jun 16, 2010 at 06:30:23AM +0000, YAMAMOTO Takashi wrote: > i think ucontext is more flexible because this way the kernel doesn't > need to know which register etc is used for tls.
In many cases, the kernel has to know about the private mapping because it has to update it on context switches. For x86, it either has to modify a GDT entry or a MSR. The actual value of %gs is otherwise irrelevant. Joerg
