From: Nicholas Piggin <npiggin@gmail•com>
To: linuxppc-dev@lists•ozlabs.org
Cc: Nicholas Piggin <npiggin@gmail•com>, Paul Mackerras <paulus@ozlabs•org>
Subject: [PATCH] powerpc/powernv: Fix SMT4 forcing idle code
Date: Sun, 1 Apr 2018 15:38:13 +1000 [thread overview]
Message-ID: <20180401053813.17405-1-npiggin@gmail.com> (raw)
PSSCR value is not stored to PACA_REQ_PSSCR in case the CPU does
not have the XER[SO] bug.
Fix this by storing up-front, outside the workaround code. The
initial test is not required because it is a slow path.
The workaround is made to depend on CONFIG_KVM_BOOK3S_HV_POSSIBLE, to
match pnv_power9_force_smt4_catch() where it is used.
Fixes: 7672691a08 ("powerpc/powernv: Provide a way to force a core into SMT4 mode")
Cc: Paul Mackerras <paulus@ozlabs•org>
Signed-off-by: Nicholas Piggin <npiggin@gmail•com>
---
arch/powerpc/kernel/idle_book3s.S | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S
index 89157cf452e3..d503203842b0 100644
--- a/arch/powerpc/kernel/idle_book3s.S
+++ b/arch/powerpc/kernel/idle_book3s.S
@@ -430,20 +430,20 @@ ALT_FTR_SECTION_END_NESTED_IFSET(CPU_FTR_ARCH_207S, 66); \
* r3 contains desired PSSCR register value.
*/
_GLOBAL(power9_idle_stop)
-BEGIN_FTR_SECTION
- lwz r5, PACA_DONT_STOP(r13)
- cmpwi r5, 0
- bne 1f
std r3, PACA_REQ_PSSCR(r13)
+#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
+BEGIN_FTR_SECTION
sync
lwz r5, PACA_DONT_STOP(r13)
cmpwi r5, 0
bne 1f
END_FTR_SECTION_IFSET(CPU_FTR_P9_TM_XER_SO_BUG)
+#endif
mtspr SPRN_PSSCR,r3
LOAD_REG_ADDR(r4,power_enter_stop)
b pnv_powersave_common
/* No return */
+#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
1:
/*
* We get here when TM / thread reconfiguration bug workaround
@@ -453,6 +453,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_P9_TM_XER_SO_BUG)
li r3, 0
std r3, PACA_REQ_PSSCR(r13)
blr /* return 0 for wakeup cause / SRR1 value */
+#endif
/*
* On waking up from stop 0,1,2 with ESL=1 on POWER9 DD1,
--
2.16.3
next reply other threads:[~2018-04-01 5:38 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-01 5:38 Nicholas Piggin [this message]
2018-04-04 14:39 ` powerpc/powernv: Fix SMT4 forcing idle code Michael Ellerman
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