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| author | Gautham R. Shenoy <ego@linux.vnet.ibm.com> | 2017-08-08 10:43:15 +0200 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2017-08-08 12:21:23 +0200 |
| commit | 785a12afdb4a52903447fd890633c82fdda4b6f7 (patch) | |
| tree | d91beb5aff31b950f8a2620306e70117c173976f /drivers/cpuidle | |
| parent | Revert "powerpc/64: Avoid restore_math call if possible in syscall exit" (diff) | |
| download | linux-785a12afdb4a52903447fd890633c82fdda4b6f7.tar.xz linux-785a12afdb4a52903447fd890633c82fdda4b6f7.zip | |
powerpc/powernv/idle: Disable LOSE_FULL_CONTEXT states when stop-api fails
Currently, we use the opal call opal_slw_set_reg() to inform the
Sleep-Winkle Engine (SLW) to restore the contents of some of the
Hypervisor state on wakeup from deep idle states that lose full
hypervisor context (characterized by the flag
OPAL_PM_LOSE_FULL_CONTEXT).
However, the current code has a bug in that if opal_slw_set_reg()
fails, we don't disable the use of these deep states (winkle on
POWER8, stop4 onwards on POWER9).
This patch fixes this bug by ensuring that if programing the
sleep-winkle engine to restore the hypervisor states in
pnv_save_sprs_for_deep_states() fails, then we exclude such states by
clearing the OPAL_PM_LOSE_FULL_CONTEXT flag from
supported_cpuidle_states. As a result POWER8 will be prevented from
using winkle for CPU-Hotplug, and POWER9 will put the offlined CPUs to
the default stop state when available.
Further, we ensure in the initialization of the cpuidle-powernv driver
to only include those states whose flags are present in
supported_cpuidle_states, thereby skipping OPAL_PM_LOSE_FULL_CONTEXT
states when they have been disabled due to stop-api failure.
Fixes: 1e1601b38e6 ("powerpc/powernv/idle: Restore SPRs for deep idle
states via stop API.")
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'drivers/cpuidle')
| -rw-r--r-- | drivers/cpuidle/cpuidle-powernv.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c index 37b0698b7193..42896a67aeae 100644 --- a/drivers/cpuidle/cpuidle-powernv.c +++ b/drivers/cpuidle/cpuidle-powernv.c @@ -235,6 +235,7 @@ static inline int validate_dt_prop_sizes(const char *prop1, int prop1_len, return -1; } +extern u32 pnv_get_supported_cpuidle_states(void); static int powernv_add_idle_states(void) { struct device_node *power_mgt; @@ -248,6 +249,8 @@ static int powernv_add_idle_states(void) const char *names[CPUIDLE_STATE_MAX]; u32 has_stop_states = 0; int i, rc; + u32 supported_flags = pnv_get_supported_cpuidle_states(); + /* Currently we have snooze statically defined */ @@ -362,6 +365,13 @@ static int powernv_add_idle_states(void) for (i = 0; i < dt_idle_states; i++) { unsigned int exit_latency, target_residency; bool stops_timebase = false; + + /* + * Skip the platform idle state whose flag isn't in + * the supported_cpuidle_states flag mask. + */ + if ((flags[i] & supported_flags) != flags[i]) + continue; /* * If an idle state has exit latency beyond * POWERNV_THRESHOLD_LATENCY_NS then don't use it |