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| author | Michael Ellerman <mpe@ellerman.id.au> | 2018-04-04 02:01:08 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2018-04-04 02:09:35 +0300 |
| commit | d0b791c02994486b21fc48949ba276c72a88938d (patch) | |
| tree | 1d4a1ba8a4c3a762c43a5560622cc10d115c1cbd /arch/powerpc/kernel/idle_book3s.S | |
| parent | f2748bdfe157343eb8cf910a1d89ccf2fd20100b (diff) | |
| download | linux-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/kernel/idle_book3s.S')
| -rw-r--r-- | arch/powerpc/kernel/idle_book3s.S | 23 |
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 |