On 17.04.19 22:58, Helge Deller wrote: > On 17.04.19 22:55, Sven Schnelle wrote: >> On Fri, Apr 12, 2019 at 07:12:04PM -0400, John David Anglin wrote: >>> TLB operations only need to be serialized on machines with the Merced (Stretch) bus. >>> The only machines in this category are L and N class, and they require a 64-bit PA 2.0 >>> kernel. On these machines, we use local TLB purges in the tmpalias routines. We don't >>> need to serialize TLB purges on all other machines. Thus, the lock/unlock code can be >>> removed when CONFIG_PA20 is not defined. Further, when CONFIG_PA20 is not defined, >>> alternative patching converts the TLB purges to local purges when PA 2.0 hardware has >>> been detected. >>> >>> Signed-off-by: John David Anglin <dave.anglin@xxxxxxxx> >> >> I had this patch running on my C8000 and J5000 for a few days, and haven't >> encountered any issues. > > Nah... > I do have one of the critical machines (rp5470), and I tried > to add the necessary code to detect and handle the TLB serialization. > Until now the patch sadly doesn't work yet (hangs at boot), it still needs more work. > You can find it in my git tree: > https://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux.git/commit/?h=tlb-flush-merced-bus&id=fc6044f83cb9828ec6ebecb23a46549d9ebc518f Please ignore my comments. Dave's patch is OK. I mixed it up with the Mikulas Patocka's patch: "use per-pagetable spinlock" https://patchwork.kernel.org/patch/10888249/ Helge
