Re: powernv: Load correct TOC pointer while waking up from winkle.
From: Michael Ellerman <hidden>
Date: 2016-08-09 11:26:41
On Fri, 2016-05-08 at 13:43:12 UTC, Mahesh Salgaonkar wrote:
From: Mahesh Salgaonkar <redacted> The function pnv_restore_hyp_resource() loads the TOC into r2 from the invalid PACA pointer before fixing r13 value. This do not affect POWER ISA 3.0 but it does have an impact on POWER ISA 2.07 or less leading CPU to get stuck forever. login: [ 471.830433] Processor 120 is stuck. This can be easily reproducible using following steps: - Turn off SMT $ ppc64_cpu --smt=off - offline/online any online cpu (Thread 0 of any core which is online) $ echo 0 > /sys/devices/system/cpu/cpu<num>/online $ echo 1 > /sys/devices/system/cpu/cpu<num>/online For POWER ISA 2.07 or less, the last bit of HSPRG0 is set indicating that thread is waking up from winkle. Hence, the last bit of HSPRG0(r13) needs to be clear before accessing it as PACA to avoid loading invalid values from invalid PACA pointer. Fix this by loading TOC after r13 register is corrected. Signed-off-by: Mahesh Salgaonkar <redacted>
Applied to powerpc fixes, thanks. https://git.kernel.org/powerpc/c/e325d76f8bd2d222a1f577aba0 cheers