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powerpc/powernv: Fix restore of SPRs upon wake up from hypervisor state loss 

pnv_wakeup_tb_loss() currently expects cr4 to be "eq" if the CPU is
waking up from a complete hypervisor state loss. Hence, it currently
restores the SPR contents only if cr4 is "eq".

However, after commit bcef83a00d ("powerpc/powernv: Add platform
support for stop instruction"), on ISA v3.0 CPUs, the function
pnv_restore_hyp_resource() sets cr4 to contain the result of the
comparison between the state the CPU has woken up from and the first
deep stop state before calling pnv_wakeup_tb_loss().

Thus if the CPU woke up from a state that is deeper than the first
deep stop state, cr4 will have "gt" set and hence, pnv_wakeup_tb_loss()
will fail to restore the SPRs on waking up from such a state.

Fix the code in pnv_wakeup_tb_loss() to restore the SPR states when cr4
is "eq" or "gt".

Fixes: bcef83a00d ("powerpc/powernv: Add platform support for stop instruction")
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Reviewed-by: Shreyas B. Prabhu <shreyasbp@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
hifive-unleashed-5.1
Gautham R. Shenoy 2016-09-07 10:46:30 +05:30 committed by Michael Ellerman
parent f077aaf075
commit bd00a240dc
1 changed files with 5 additions and 5 deletions
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10
arch/powerpc/kernel/idle_book3s.S
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@ -411,7 +411,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
*
* r13 - PACA
* cr3 - gt if waking up with partial/complete hypervisor state loss
* cr4 - eq if waking up from complete hypervisor state loss.
* cr4 - gt or eq if waking up from complete hypervisor state loss.
*/
_GLOBAL(pnv_wakeup_tb_loss)
ld r1,PACAR1(r13)
@ -453,7 +453,7 @@ lwarx_loop2:
* At this stage
* cr2 - eq if first thread to wakeup in core
* cr3- gt if waking up with partial/complete hypervisor state loss
* cr4 - eq if waking up from complete hypervisor state loss.
* cr4 - gt or eq if waking up from complete hypervisor state loss.
*/
ori r15,r15,PNV_CORE_IDLE_LOCK_BIT
@ -481,7 +481,7 @@ first_thread_in_subcore:
* If waking up from sleep, subcore state is not lost. Hence
* skip subcore state restore
*/
bne cr4,subcore_state_restored
blt cr4,subcore_state_restored
/* Restore per-subcore state */
ld r4,_SDR1(r1)
@ -526,7 +526,7 @@ timebase_resync:
* If waking up from sleep, per core state is not lost, skip to
* clear_lock.
*/
bne cr4,clear_lock
blt cr4,clear_lock
/*
* First thread in the core to wake up and its waking up with
@ -557,7 +557,7 @@ common_exit:
* If waking up from sleep, hypervisor state is not lost. Hence
* skip hypervisor state restore.
*/
bne cr4,hypervisor_state_restored
blt cr4,hypervisor_state_restored
/* Waking up from winkle */