• Mahesh Salgaonkar's avatar
    powerpc/powernv: Load correct TOC pointer while waking up from winkle. · e325d76f
    Mahesh Salgaonkar authored
    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.
    
    Fixes: bcef83a0
    
     ("powerpc/powernv: Add platform support for stop instruction")
    Signed-off-by: default avatarMahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
    Acked-by: default avatarVaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
    Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
    e325d76f
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