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powerpc/powernv: Fixes for hypervisor doorbell handling

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Since we can now use hypervisor doorbells for host IPIs, this makes
sure we clear the host IPI flag when taking a doorbell interrupt, and
clears any pending doorbell IPI in pnv_smp_cpu_kill_self() (as we
already do for IPIs sent via the XICS interrupt controller).  Otherwise
if there did happen to be a leftover pending doorbell interrupt for
an offline CPU thread for any reason, it would prevent that thread from
going into a power-saving mode; it would instead keep waking up because
of the interrupt.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Paul Mackerras 2015-03-19 19:29:01 +11:00 committed by Michael Ellerman
parent 06e5801b8c
commit 755563bc79
4 changed files with 20 additions and 2 deletions
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3
arch/powerpc/include/asm/ppc-opcode.h
View File

@ -153,6 +153,7 @@
#define PPC_INST_MFSPR_PVR_MASK 0xfc1fffff
#define PPC_INST_MFTMR 0x7c0002dc
#define PPC_INST_MSGSND 0x7c00019c
#define PPC_INST_MSGCLR 0x7c0001dc
#define PPC_INST_MSGSNDP 0x7c00011c
#define PPC_INST_MTTMR 0x7c0003dc
#define PPC_INST_NOP 0x60000000
@ -309,6 +310,8 @@
___PPC_RB(b) | __PPC_EH(eh))
#define PPC_MSGSND(b) stringify_in_c(.long PPC_INST_MSGSND | \
___PPC_RB(b))
#define PPC_MSGCLR(b) stringify_in_c(.long PPC_INST_MSGCLR | \
___PPC_RB(b))
#define PPC_MSGSNDP(b) stringify_in_c(.long PPC_INST_MSGSNDP | \
___PPC_RB(b))
#define PPC_POPCNTB(a, s) stringify_in_c(.long PPC_INST_POPCNTB | \

3
arch/powerpc/include/asm/reg.h
View File

@ -608,13 +608,16 @@
#define SRR1_ISI_N_OR_G 0x10000000 /* ISI: Access is no-exec or G */
#define SRR1_ISI_PROT 0x08000000 /* ISI: Other protection fault */
#define SRR1_WAKEMASK 0x00380000 /* reason for wakeup */
#define SRR1_WAKEMASK_P8 0x003c0000 /* reason for wakeup on POWER8 */
#define SRR1_WAKESYSERR 0x00300000 /* System error */
#define SRR1_WAKEEE 0x00200000 /* External interrupt */
#define SRR1_WAKEMT 0x00280000 /* mtctrl */
#define SRR1_WAKEHMI 0x00280000 /* Hypervisor maintenance */
#define SRR1_WAKEDEC 0x00180000 /* Decrementer interrupt */
#define SRR1_WAKEDBELL 0x00140000 /* Privileged doorbell on P8 */
#define SRR1_WAKETHERM 0x00100000 /* Thermal management interrupt */
#define SRR1_WAKERESET 0x00100000 /* System reset */
#define SRR1_WAKEHDBELL 0x000c0000 /* Hypervisor doorbell on P8 */
#define SRR1_WAKESTATE 0x00030000 /* Powersave exit mask [46:47] */
#define SRR1_WS_DEEPEST 0x00030000 /* Some resources not maintained,
* may not be recoverable */

2
arch/powerpc/kernel/dbell.c
View File

@ -17,6 +17,7 @@
#include <asm/dbell.h>
#include <asm/irq_regs.h>
#include <asm/kvm_ppc.h>
#ifdef CONFIG_SMP
void doorbell_setup_this_cpu(void)
@ -41,6 +42,7 @@ void doorbell_exception(struct pt_regs *regs)
may_hard_irq_enable();
kvmppc_set_host_ipi(smp_processor_id(), 0);
__this_cpu_inc(irq_stat.doorbell_irqs);
smp_ipi_demux();

14
arch/powerpc/platforms/powernv/smp.c
View File

@ -33,6 +33,8 @@
#include <asm/runlatch.h>
#include <asm/code-patching.h>
#include <asm/dbell.h>
#include <asm/kvm_ppc.h>
#include <asm/ppc-opcode.h>
#include "powernv.h"
@ -149,7 +151,7 @@ static int pnv_smp_cpu_disable(void)
static void pnv_smp_cpu_kill_self(void)
{
unsigned int cpu;
unsigned long srr1;
unsigned long srr1, wmask;
u32 idle_states;
/* Standard hot unplug procedure */
@ -161,6 +163,10 @@ static void pnv_smp_cpu_kill_self(void)
generic_set_cpu_dead(cpu);
smp_wmb();
wmask = SRR1_WAKEMASK;
if (cpu_has_feature(CPU_FTR_ARCH_207S))
wmask = SRR1_WAKEMASK_P8;
idle_states = pnv_get_supported_cpuidle_states();
/* We don't want to take decrementer interrupts while we are offline,
* so clear LPCR:PECE1. We keep PECE2 enabled.
@ -191,10 +197,14 @@ static void pnv_smp_cpu_kill_self(void)
* having finished executing in a KVM guest, then srr1
* contains 0.
*/
if ((srr1 & SRR1_WAKEMASK) == SRR1_WAKEEE) {
if ((srr1 & wmask) == SRR1_WAKEEE) {
icp_native_flush_interrupt();
local_paca->irq_happened &= PACA_IRQ_HARD_DIS;
smp_mb();
} else if ((srr1 & wmask) == SRR1_WAKEHDBELL) {
unsigned long msg = PPC_DBELL_TYPE(PPC_DBELL_SERVER);
asm volatile(PPC_MSGCLR(%0) : : "r" (msg));
kvmppc_set_host_ipi(cpu, 0);
}
if (cpu_core_split_required())