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authorMichael Ellerman <mpe@ellerman.id.au>2018-04-04 02:01:08 +0300
committerMichael Ellerman <mpe@ellerman.id.au>2018-04-04 02:09:35 +0300
commitd0b791c02994486b21fc48949ba276c72a88938d (patch)
tree1d4a1ba8a4c3a762c43a5560622cc10d115c1cbd /arch/powerpc
parentf2748bdfe157343eb8cf910a1d89ccf2fd20100b (diff)
downloadlinux-d0b791c02994486b21fc48949ba276c72a88938d.tar.xz
powerpc/64s/idle: Consolidate power9_offline_stop()/power9_idle_stop()
Commit 3d4fbffdd703 ("powerpc/64s/idle: POWER9 implement a separate idle stop function for hotplug") that added power9_offline_stop() was written before commit 7672691a08c8 ("powerpc/powernv: Provide a way to force a core into SMT4 mode"). When merging the former I failed to notice that it caused us to skip the force-SMT4 logic for offline CPUs. The result is that offlined CPUs will not correctly participate in the force-SMT4 logic, which presumably will result in badness (not tested). Reconcile the two commits by making power9_offline_stop() a pre-cursor to power9_idle_stop(), so that they share the force-SMT4 logic. This is based on an original commit from Nick, all breakage is my own. Fixes: 3d4fbffdd703 ("powerpc/64s/idle: POWER9 implement a separate idle stop function for hotplug") Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Diffstat (limited to 'arch/powerpc')
-rw-r--r--arch/powerpc/kernel/idle_book3s.S23
1 files changed, 11 insertions, 12 deletions
diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S
index 81defb6a9b74..e5cb3eedb564 100644
--- a/arch/powerpc/kernel/idle_book3s.S
+++ b/arch/powerpc/kernel/idle_book3s.S
@@ -422,25 +422,24 @@ ALT_FTR_SECTION_END_NESTED_IFSET(CPU_FTR_ARCH_207S, 66); \
/*
* Entered with MSR[EE]=0 and no soft-masked interrupts pending.
* r3 contains desired PSSCR register value.
+ *
+ * Offline (CPU unplug) case also must notify KVM that the CPU is
+ * idle.
*/
_GLOBAL(power9_offline_stop)
- std r3, PACA_REQ_PSSCR(r13)
- mtspr SPRN_PSSCR,r3
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
- /* Tell KVM we're entering idle */
+ /*
+ * Tell KVM we're entering idle.
+ * This does not have to be done in real mode because the P9 MMU
+ * is independent per-thread. Some steppings share radix/hash mode
+ * between threads, but in that case KVM has a barrier sync in real
+ * mode before and after switching between radix and hash.
+ */
li r4,KVM_HWTHREAD_IN_IDLE
- /* DO THIS IN REAL MODE! See comment above. */
stb r4,HSTATE_HWTHREAD_STATE(r13)
#endif
- LOAD_REG_ADDR(r4,power_enter_stop)
- b pnv_powersave_common
- /* No return */
+ /* fall through */
-
-/*
- * Entered with MSR[EE]=0 and no soft-masked interrupts pending.
- * r3 contains desired PSSCR register value.
- */
_GLOBAL(power9_idle_stop)
std r3, PACA_REQ_PSSCR(r13)
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE