On Tue, Mar 13, 2007 at 05:23:52PM +1100, Rusty Russell wrote: > On Tue, 2007-03-13 at 08:59 +1100, Rusty Russell wrote: > > On Mon, 2007-03-12 at 10:48 +0100, Andi Kleen wrote: > > > > Rusty's pda->per_cpu patch will deal with this once and for all; have > > > > > > Not on x86-64. > > > > Indeed. Perhaps it's time I join the modern world and compile a 64-bit > > kernel... > > > > Will prepare patches, > > No, I don't think I will. The PDA concept has gone too far in x86-64 to > be undone. In particular, it's been put in GCC 4.1 for > CONFIG_CC_STACKPROTECTOR, which assumes %gs:40 will give the stack > canary.
Yes that was always ugly, but I don't know a better way. > For the record: the PDA should never have existed, that's what percpu > vars were supposed to be for. Something went wrong here 8( PDA predates per cpu. > The ideal solution has always been to use __thread, but no architecture > has yet managed it (I tried for i386, and it quickly caused unbearable I tried it too, but __thread is hopeless for kernel code > pain). On x86-64 that uses "%fs" on x86-64, not "%gs" as the kernel > does, but I might try that if I feel particularly masochistic soon... Then swapgs wouldn't work anymore (there is no swapfs) -Andi > - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
