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Commit bd00a240 authored by Gautham R. Shenoy's avatar Gautham R. Shenoy Committed by Michael Ellerman
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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 bcef83a0 ("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: bcef83a0 ("powerpc/powernv: Add platform support for stop instruction")
Signed-off-by: default avatarGautham R. Shenoy <ego@linux.vnet.ibm.com>
Reviewed-by: default avatarShreyas B. Prabhu <shreyasbp@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent f077aaf0

arch/powerpc/kernel/idle_book3s.S

+5 −5
Original line number Diff line number Diff line
@@ -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 */