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authorGautham R. Shenoy <ego@linux.vnet.ibm.com>2017-08-08 11:43:15 +0300
committerMichael Ellerman <mpe@ellerman.id.au>2017-08-08 13:21:23 +0300
commit785a12afdb4a52903447fd890633c82fdda4b6f7 (patch)
treed91beb5aff31b950f8a2620306e70117c173976f /drivers/cpuidle/cpuidle-powernv.c
parent44a12806d010944a5727f1dc99123121e3e2c8c6 (diff)
downloadlinux-785a12afdb4a52903447fd890633c82fdda4b6f7.tar.xz
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/cpuidle-powernv.c')
-rw-r--r--drivers/cpuidle/cpuidle-powernv.c10
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