[PATCH v3 4/4] powernv: powerpc: Add winkle support for offline cpus

From: Shreyas B. Prabhu
Date: Thu Dec 04 2014 - 02:29:43 EST

Winkle is a deep idle state supported in power8 chips. A core enters
winkle when all the threads of the core enter winkle. In this state
power supply to the entire chiplet i.e core, private L2 and private L3
is turned off. As a result it gives higher powersavings compared to
sleep.

But entering winkle results in a total hypervisor state loss. Hence the
hypervisor context has to be preserved before entering winkle and
restored upon wake up.

Power-on Reset Engine (PORE) is a dedicated engine which is responsible
for powering on the chiplet during wake up. It can be programmed to
restore the register contests of a few specific registers. This patch
uses PORE to restore register state wherever possible and uses stack to
save and restore rest of the necessary registers.

With hypervisor state restore things fall under three categories-
per-core state, per-subcore state and per-thread state. To manage this,
extend the infrastructure introduced for sleep. Mainly we add a paca
variable subcore_sibling_mask. Using this and the core_idle_state we can
distingush first thread in core and subcore.

Signed-off-by: Shreyas B. Prabhu <shreyas@xxxxxxxxxxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: linuxppc-dev@xxxxxxxxxxxxxxxx
---
arch/powerpc/include/asm/opal.h | 3 +
arch/powerpc/include/asm/paca.h | 2 +
arch/powerpc/include/asm/ppc-opcode.h | 2 +
arch/powerpc/include/asm/processor.h | 1 +
arch/powerpc/include/asm/reg.h | 2 +
arch/powerpc/kernel/asm-offsets.c | 2 +
arch/powerpc/kernel/exceptions-64s.S | 16 ++-
arch/powerpc/kernel/idle_power7.S | 151 +++++++++++++++++++++++--
arch/powerpc/platforms/powernv/opal-wrappers.S | 1 +
arch/powerpc/platforms/powernv/setup.c | 73 ++++++++++++
arch/powerpc/platforms/powernv/smp.c | 4 +-
arch/powerpc/platforms/powernv/subcore.c | 34 ++++++
arch/powerpc/platforms/powernv/subcore.h | 1 +
13 files changed, 280 insertions(+), 12 deletions(-)

diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h
index bef7fbc..f0ca2d9 100644
--- a/arch/powerpc/include/asm/opal.h
+++ b/arch/powerpc/include/asm/opal.h
@@ -153,6 +153,7 @@ struct opal_sg_list {
#define OPAL_PCI_EEH_FREEZE_SET 97
#define OPAL_HANDLE_HMI 98
#define OPAL_CONFIG_CPU_IDLE_STATE 99
+#define OPAL_SLW_SET_REG 100
#define OPAL_REGISTER_DUMP_REGION 101
#define OPAL_UNREGISTER_DUMP_REGION 102

@@ -163,6 +164,7 @@ struct opal_sg_list {
*/
#define OPAL_PM_NAP_ENABLED 0x00010000
#define OPAL_PM_SLEEP_ENABLED 0x00020000
+#define OPAL_PM_WINKLE_ENABLED 0x00040000
#define OPAL_PM_SLEEP_ENABLED_ER1 0x00080000

#ifndef __ASSEMBLY__
@@ -972,6 +974,7 @@ int64_t opal_sensor_read(uint32_t sensor_hndl, int token, __be32 *sensor_data);
int64_t opal_handle_hmi(void);
int64_t opal_register_dump_region(uint32_t id, uint64_t start, uint64_t end);
int64_t opal_unregister_dump_region(uint32_t id);
+int64_t opal_slw_set_reg(uint64_t cpu_pir, uint64_t sprn, uint64_t val);
int64_t opal_pci_set_phb_cxl_mode(uint64_t phb_id, uint64_t mode, uint64_t pe_number);

/* Internal functions */
diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h
index e4578c3..e89f4a4 100644
--- a/arch/powerpc/include/asm/paca.h
+++ b/arch/powerpc/include/asm/paca.h
@@ -164,6 +164,8 @@ struct paca_struct {
u8 thread_idle_state; /* ~Idle[0]/Nap[1]/Sleep[2]/Winkle[3] */
/* Mask to indicate thread id in core */
u8 thread_mask;
+ /* Mask to denote subcore sibling threads */
+ u8 subcore_sibling_mask;
#endif
#ifdef CONFIG_PPC_BOOK3S_64
/* Exclusive emergency stack pointer for machine check exception. */
diff --git a/arch/powerpc/include/asm/ppc-opcode.h b/arch/powerpc/include/asm/ppc-opcode.h
index 6f85362..5155be7 100644
--- a/arch/powerpc/include/asm/ppc-opcode.h
+++ b/arch/powerpc/include/asm/ppc-opcode.h
@@ -194,6 +194,7 @@

#define PPC_INST_NAP 0x4c000364
#define PPC_INST_SLEEP 0x4c0003a4
+#define PPC_INST_WINKLE 0x4c0003e4

/* A2 specific instructions */
#define PPC_INST_ERATWE 0x7c0001a6
@@ -374,6 +375,7 @@

#define PPC_NAP stringify_in_c(.long PPC_INST_NAP)
#define PPC_SLEEP stringify_in_c(.long PPC_INST_SLEEP)
+#define PPC_WINKLE stringify_in_c(.long PPC_INST_WINKLE)

/* BHRB instructions */
#define PPC_CLRBHRB stringify_in_c(.long PPC_INST_CLRBHRB)
diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
index dda7ac4..c076842 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -453,6 +453,7 @@ enum idle_boot_override {IDLE_NO_OVERRIDE = 0, IDLE_POWERSAVE_OFF};
extern int powersave_nap; /* set if nap mode can be used in idle loop */
extern void power7_nap(int check_irq);
extern void power7_sleep(void);
+extern void power7_winkle(void);
extern void flush_instruction_cache(void);
extern void hard_reset_now(void);
extern void poweroff_now(void);
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index a68ee15..1c874fb 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -373,6 +373,7 @@
#define SPRN_DBAT7L 0x23F /* Data BAT 7 Lower Register */
#define SPRN_DBAT7U 0x23E /* Data BAT 7 Upper Register */
#define SPRN_PPR 0x380 /* SMT Thread status Register */
+#define SPRN_TSCR 0x399 /* Thread Switch Control Register */

#define SPRN_DEC 0x016 /* Decrement Register */
#define SPRN_DER 0x095 /* Debug Enable Regsiter */
@@ -730,6 +731,7 @@
#define SPRN_BESCR 806 /* Branch event status and control register */
#define BESCR_GE 0x8000000000000000ULL /* Global Enable */
#define SPRN_WORT 895 /* Workload optimization register - thread */
+#define SPRN_WORC 863 /* Workload optimization register - core */

#define SPRN_PMC1 787
#define SPRN_PMC2 788
diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index 3bc0352..f262e3e 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -737,6 +737,8 @@ int main(void)
offsetof(struct paca_struct, thread_idle_state));
DEFINE(PACA_THREAD_MASK,
offsetof(struct paca_struct, thread_mask));
+ DEFINE(PACA_SUBCORE_SIBLING_MASK,
+ offsetof(struct paca_struct, subcore_sibling_mask));
#endif

return 0;
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 7637889..2b9b5fb 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -102,9 +102,7 @@ system_reset_pSeries:
#ifdef CONFIG_PPC_P7_NAP
BEGIN_FTR_SECTION
/* Running native on arch 2.06 or later, check if we are
- * waking up from nap. We only handle no state loss and
- * supervisor state loss. We do -not- handle hypervisor
- * state loss at this time.
+ * waking up from nap/sleep/winkle.
*/
mfspr r13,SPRN_SRR1
rlwinm. r13,r13,47-31,30,31
@@ -112,7 +110,17 @@ BEGIN_FTR_SECTION

cmpwi cr3,r13,2

- GET_PACA(r13)
+ /* Check if last bit of HSPGR0 is set. This indicates whether we are
+ * waking up from winkle */
+ li r3,1
+ mfspr r4,SPRN_HSPRG0
+ and r5,r4,r3
+ cmpwi cr4,r5,1 /* Store result in cr4 for later use */
+
+ andc r4,r4,r3
+ mtspr SPRN_HSPRG0,r4
+
+ mr r13,r4
lbz r0,PACA_THREAD_IDLE_STATE(r13)
cmpwi cr2,r0,PNV_THREAD_NAP
bgt cr2,8f /* Either sleep or Winkle */
diff --git a/arch/powerpc/kernel/idle_power7.S b/arch/powerpc/kernel/idle_power7.S
index 8c3a1f4..8102075 100644
--- a/arch/powerpc/kernel/idle_power7.S
+++ b/arch/powerpc/kernel/idle_power7.S
@@ -19,8 +19,24 @@
#include <asm/kvm_book3s_asm.h>
#include <asm/opal.h>
#include <asm/cpuidle.h>
+#include <asm/mmu-hash64.h>

#undef DEBUG
+/*
+ * Use unused space in the interrupt stack to save and restore
+ * registers for winkle support.
+ */
+#define _SDR1 GPR3
+#define _RPR GPR4
+#define _SPURR GPR5
+#define _PURR GPR6
+#define _TSCR GPR7
+#define _DSCR GPR8
+#define _AMOR GPR9
+#define _PMC5 GPR10
+#define _PMC6 GPR11
+#define _WORT GPR12
+#define _WORC GPR13

/* Idle state entry routines */

@@ -124,8 +140,8 @@ power7_enter_nap_mode:
stb r4,HSTATE_HWTHREAD_STATE(r13)
#endif
stb r3,PACA_THREAD_IDLE_STATE(r13)
- cmpwi cr1,r3,PNV_THREAD_SLEEP
- bge cr1,2f
+ cmpwi cr3,r3,PNV_THREAD_SLEEP
+ bge cr3,2f
IDLE_STATE_ENTER_SEQ(PPC_NAP)
/* No return */
2:
@@ -154,7 +170,8 @@ pnv_fastsleep_workaround_at_entry:
isync
bne- lwarx_loop1

-common_enter: /* common code for all the threads entering sleep */
+common_enter: /* common code for all the threads entering sleep or winkle */
+ bgt cr3,enter_winkle
IDLE_STATE_ENTER_SEQ(PPC_SLEEP)

fastsleep_workaround_at_entry:
@@ -175,6 +192,34 @@ fastsleep_workaround_at_entry:
stw r0,0(r14)
b common_enter

+enter_winkle:
+ /*
+ * Note all register i.e per-core, per-subcore or per-thread is saved
+ * here since any thread in the core might wake up first
+ */
+ mfspr r3,SPRN_SDR1
+ std r3,_SDR1(r1)
+ mfspr r3,SPRN_RPR
+ std r3,_RPR(r1)
+ mfspr r3,SPRN_SPURR
+ std r3,_SPURR(r1)
+ mfspr r3,SPRN_PURR
+ std r3,_PURR(r1)
+ mfspr r3,SPRN_TSCR
+ std r3,_TSCR(r1)
+ mfspr r3,SPRN_DSCR
+ std r3,_DSCR(r1)
+ mfspr r3,SPRN_AMOR
+ std r3,_AMOR(r1)
+ mfspr r3,SPRN_PMC5
+ std r3,_PMC5(r1)
+ mfspr r3,SPRN_PMC6
+ std r3,_PMC6(r1)
+ mfspr r3,SPRN_WORT
+ std r3,_WORT(r1)
+ mfspr r3,SPRN_WORC
+ std r3,_WORC(r1)
+ IDLE_STATE_ENTER_SEQ(PPC_WINKLE)

_GLOBAL(power7_idle)
/* Now check if user or arch enabled NAP mode */
@@ -197,6 +242,12 @@ _GLOBAL(power7_sleep)
b power7_powersave_common
/* No return */

+_GLOBAL(power7_winkle)
+ li r3,3
+ li r4,1
+ b power7_powersave_common
+ /* No return */
+
#define CHECK_HMI_INTERRUPT \
mfspr r0,SPRN_SRR1; \
BEGIN_FTR_SECTION_NESTED(66); \
@@ -238,11 +289,23 @@ lwarx_loop2:
bne core_idle_lock_held

cmpwi cr2,r15,0
+ lbz r4,PACA_SUBCORE_SIBLING_MASK(r13)
+ and r4,r4,r15
+ cmpwi cr1,r4,0 /* Check if first in subcore */
+
+ /*
+ * At this stage
+ * cr1 - 10 if first thread to wakeup in subcore
+ * cr2 - 10 if first thread to wakeup in core
+ * cr3- 01 if waking up from sleep or winkle
+ * cr4 - 10 if waking up from winkle
+ */
+
or r15,r15,r7 /* Set thread bit */

- beq cr2,first_thread
+ beq cr1,first_thread_in_subcore

- /* Not first thread in core to wake up */
+ /* Not first thread in subcore to wake up */
stwcx. r15,0,r14
isync
bne- lwarx_loop2
@@ -257,14 +320,35 @@ core_idle_lock_loop:
HMT_MEDIUM
b lwarx_loop2

-first_thread:
- /* First thread in core to wakeup */
+first_thread_in_subcore:
+ /* First thread in subcore to wakeup */
ori r15,r15,PNV_CORE_IDLE_LOCK_BIT
stwcx. r15,0,r14
isync
bne- lwarx_loop2

/*
+ * If waking up from sleep, subcore state is not lost. Hence
+ * skip subcore state restore
+ */
+ bne cr4,subcore_state_restored
+
+ /* Restore per-subcore state */
+ ld r4,_SDR1(r1)
+ mtspr SPRN_SDR1,r4
+ ld r4,_RPR(r1)
+ mtspr SPRN_RPR,r4
+ ld r4,_AMOR(r1)
+ mtspr SPRN_AMOR,r4
+
+subcore_state_restored:
+ /* Check if the thread is also the first thread in the core. If not,
+ * skip to clear_lock */
+ bne cr2,clear_lock
+
+first_thread_in_core:
+
+ /*
* First thread in the core waking up from fastsleep. It needs to
* call the fastsleep workaround code if the platform requires it.
* Call it unconditionally here. The below branch instruction will
@@ -284,12 +368,65 @@ timebase_resync:
bl opal_call_realmode;
/* TODO: Check r3 for failure */

+ /*
+ * If waking up from sleep, per core state is not lost, skip to
+ * clear_lock.
+ */
+ bne cr4,clear_lock
+
+ /* Restore per core state */
+ ld r4,_TSCR(r1)
+ mtspr SPRN_TSCR,r4
+ ld r4,_WORC(r1)
+ mtspr SPRN_WORC,r4
+
clear_lock:
andi. r15,r15,PNV_CORE_IDLE_THREAD_BITS
lwsync
stw r15,0(r14)

common_exit:
+ /* Common to all threads
+ *
+ * If waking up from sleep, hypervisor state is not lost. Hence
+ * skip hypervisor state restore.
+ */
+ bne cr4,hypervisor_state_restored
+
+ /* Waking up from winkle */
+
+ /* Restore per thread state */
+ bl __restore_cpu_power8
+
+ /* Restore SLB from PACA */
+ ld r8,PACA_SLBSHADOWPTR(r13)
+
+ .rept SLB_NUM_BOLTED
+ li r3, SLBSHADOW_SAVEAREA
+ LDX_BE r5, r8, r3
+ addi r3, r3, 8
+ LDX_BE r6, r8, r3
+ andis. r7,r5,SLB_ESID_V@h
+ beq 1f
+ slbmte r6,r5
+1: addi r8,r8,16
+ .endr
+
+ ld r4,_SPURR(r1)
+ mtspr SPRN_SPURR,r4
+ ld r4,_PURR(r1)
+ mtspr SPRN_PURR,r4
+ ld r4,_DSCR(r1)
+ mtspr SPRN_DSCR,r4
+ ld r4,_PMC5(r1)
+ mtspr SPRN_PMC5,r4
+ ld r4,_PMC6(r1)
+ mtspr SPRN_PMC6,r4
+ ld r4,_WORT(r1)
+ mtspr SPRN_WORT,r4
+
+hypervisor_state_restored:
+
li r5,PNV_THREAD_RUNNING
stb r5,PACA_THREAD_IDLE_STATE(r13)

diff --git a/arch/powerpc/platforms/powernv/opal-wrappers.S b/arch/powerpc/platforms/powernv/opal-wrappers.S
index a0f43e8..72b4af8 100644
--- a/arch/powerpc/platforms/powernv/opal-wrappers.S
+++ b/arch/powerpc/platforms/powernv/opal-wrappers.S
@@ -284,6 +284,7 @@ OPAL_CALL(opal_sensor_read, OPAL_SENSOR_READ);
OPAL_CALL(opal_get_param, OPAL_GET_PARAM);
OPAL_CALL(opal_set_param, OPAL_SET_PARAM);
OPAL_CALL(opal_handle_hmi, OPAL_HANDLE_HMI);
+OPAL_CALL(opal_slw_set_reg, OPAL_SLW_SET_REG);
OPAL_CALL(opal_register_dump_region, OPAL_REGISTER_DUMP_REGION);
OPAL_CALL(opal_unregister_dump_region, OPAL_UNREGISTER_DUMP_REGION);
OPAL_CALL(opal_pci_set_phb_cxl_mode, OPAL_PCI_SET_PHB_CXL_MODE);
diff --git a/arch/powerpc/platforms/powernv/setup.c b/arch/powerpc/platforms/powernv/setup.c
index 97e0279..a0de28c 100644
--- a/arch/powerpc/platforms/powernv/setup.c
+++ b/arch/powerpc/platforms/powernv/setup.c
@@ -41,6 +41,7 @@
#include <asm/code-patching.h>

#include "powernv.h"
+#include "subcore.h"

static void __init pnv_setup_arch(void)
{
@@ -294,6 +295,74 @@ static void __init pnv_setup_machdep_rtas(void)
#endif /* CONFIG_PPC_POWERNV_RTAS */

static u32 supported_cpuidle_states;
+int pnv_save_sprs_for_winkle(void)
+{
+ int cpu;
+ int rc;
+
+ /*
+ * hid0, hid1, hid4, hid5, hmeer and lpcr values are symmetric accross
+ * all cpus at boot. Get these reg values of current cpu and use the
+ * same accross all cpus.
+ */
+ uint64_t lpcr_val = mfspr(SPRN_LPCR);
+ uint64_t hid0_val = mfspr(SPRN_HID0);
+ uint64_t hid1_val = mfspr(SPRN_HID1);
+ uint64_t hid4_val = mfspr(SPRN_HID4);
+ uint64_t hid5_val = mfspr(SPRN_HID5);
+ uint64_t hmeer_val = mfspr(SPRN_HMEER);
+
+ for_each_possible_cpu(cpu) {
+ uint64_t pir = get_hard_smp_processor_id(cpu);
+ uint64_t hsprg0_val = (uint64_t)&paca[cpu];
+
+ /*
+ * HSPRG0 is used to store the cpu's pointer to paca. Hence last
+ * 3 bits are guaranteed to be 0. Program slw to restore HSPRG0
+ * with 63rd bit set, so that when a thread wakes up at 0x100 we
+ * can use this bit to distinguish between fastsleep and
+ * deep winkle.
+ */
+ hsprg0_val |= 1;
+
+ rc = opal_slw_set_reg(pir, SPRN_HSPRG0, hsprg0_val);
+ if (rc != 0)
+ return rc;
+
+ rc = opal_slw_set_reg(pir, SPRN_LPCR, lpcr_val);
+ if (rc != 0)
+ return rc;
+
+ /* HIDs are per core registers */
+ if (cpu_thread_in_core(cpu) == 0) {
+
+ rc = opal_slw_set_reg(pir, SPRN_HMEER, hmeer_val);
+ if (rc != 0)
+ return rc;
+
+ rc = opal_slw_set_reg(pir, SPRN_HID0, hid0_val);
+ if (rc != 0)
+ return rc;
+
+ rc = opal_slw_set_reg(pir, SPRN_HID1, hid1_val);
+ if (rc != 0)
+ return rc;
+
+ rc = opal_slw_set_reg(pir, SPRN_HID4, hid4_val);
+ if (rc != 0)
+ return rc;
+
+ rc = opal_slw_set_reg(pir, SPRN_HID5, hid5_val);
+ if (rc != 0)
+ return rc;
+
+ }
+
+ }
+
+ return 0;
+
+}

static void pnv_alloc_idle_core_states(void)
{
@@ -325,6 +394,10 @@ static void pnv_alloc_idle_core_states(void)
paca[cpu].thread_mask = 1 << (cpu % threads_per_core);
}
}
+ update_subcore_sibling_mask();
+ if (supported_cpuidle_states & OPAL_PM_WINKLE_ENABLED)
+ pnv_save_sprs_for_winkle();
+
}

u32 pnv_get_supported_cpuidle_states(void)
diff --git a/arch/powerpc/platforms/powernv/smp.c b/arch/powerpc/platforms/powernv/smp.c
index 12b761a..5e35857 100644
--- a/arch/powerpc/platforms/powernv/smp.c
+++ b/arch/powerpc/platforms/powernv/smp.c
@@ -167,7 +167,9 @@ static void pnv_smp_cpu_kill_self(void)
mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) & ~(u64)LPCR_PECE1);
while (!generic_check_cpu_restart(cpu)) {
ppc64_runlatch_off();
- if ((idle_states & OPAL_PM_SLEEP_ENABLED) ||
+ if (idle_states & OPAL_PM_WINKLE_ENABLED)
+ power7_winkle();
+ else if ((idle_states & OPAL_PM_SLEEP_ENABLED) ||
(idle_states & OPAL_PM_SLEEP_ENABLED_ER1))
power7_sleep();
else
diff --git a/arch/powerpc/platforms/powernv/subcore.c b/arch/powerpc/platforms/powernv/subcore.c
index c87f96b..f60f80a 100644
--- a/arch/powerpc/platforms/powernv/subcore.c
+++ b/arch/powerpc/platforms/powernv/subcore.c
@@ -160,6 +160,18 @@ static void wait_for_sync_step(int step)
mb();
}

+static void update_hid_in_slw(u64 hid0)
+{
+ u64 idle_states = pnv_get_supported_cpuidle_states();
+
+ if (idle_states & OPAL_PM_WINKLE_ENABLED) {
+ /* OPAL call to patch slw with the new HID0 value */
+ u64 cpu_pir = hard_smp_processor_id();
+
+ opal_slw_set_reg(cpu_pir, SPRN_HID0, hid0);
+ }
+}
+
static void unsplit_core(void)
{
u64 hid0, mask;
@@ -179,6 +191,7 @@ static void unsplit_core(void)
hid0 = mfspr(SPRN_HID0);
hid0 &= ~HID0_POWER8_DYNLPARDIS;
mtspr(SPRN_HID0, hid0);
+ update_hid_in_slw(hid0);

while (mfspr(SPRN_HID0) & mask)
cpu_relax();
@@ -215,6 +228,7 @@ static void split_core(int new_mode)
hid0 = mfspr(SPRN_HID0);
hid0 |= HID0_POWER8_DYNLPARDIS | split_parms[i].value;
mtspr(SPRN_HID0, hid0);
+ update_hid_in_slw(hid0);

/* Wait for it to happen */
while (!(mfspr(SPRN_HID0) & split_parms[i].mask))
@@ -251,6 +265,25 @@ bool cpu_core_split_required(void)
return true;
}

+void update_subcore_sibling_mask(void)
+{
+ int cpu;
+ /*
+ * sibling mask for the first cpu. Left shift this by required bits
+ * to get sibling mask for the rest of the cpus.
+ */
+ int sibling_mask_first_cpu = (1 << threads_per_subcore) - 1;
+
+ for_each_possible_cpu(cpu) {
+ int tid = cpu_thread_in_core(cpu);
+ int offset = (tid / threads_per_subcore) * threads_per_subcore;
+ int mask = sibling_mask_first_cpu << offset;
+
+ paca[cpu].subcore_sibling_mask = mask;
+
+ }
+}
+
static int cpu_update_split_mode(void *data)
{
int cpu, new_mode = *(int *)data;
@@ -284,6 +317,7 @@ static int cpu_update_split_mode(void *data)
/* Make the new mode public */
subcores_per_core = new_mode;
threads_per_subcore = threads_per_core / subcores_per_core;
+ update_subcore_sibling_mask();

/* Make sure the new mode is written before we exit */
mb();
diff --git a/arch/powerpc/platforms/powernv/subcore.h b/arch/powerpc/platforms/powernv/subcore.h
index 148abc9..604eb40 100644
--- a/arch/powerpc/platforms/powernv/subcore.h
+++ b/arch/powerpc/platforms/powernv/subcore.h
@@ -15,4 +15,5 @@

#ifndef __ASSEMBLY__
void split_core_secondary_loop(u8 *state);
+extern void update_subcore_sibling_mask(void);
#endif
--
1.9.3

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