On 03/15/2017 01:45 PM, Gautham R. Shenoy wrote:
> From: "Gautham R. Shenoy" <e...@linux.vnet.ibm.com>
>
> The various properties associated with powernv idle states such as
> names, flags, residency-ns, latencies-ns, psscr, psscr-mask are
> exposed in the device-tree as property arrays such the pointwise
> entries in each of these arrays correspond to the properties of the
> same idle state.
>
> This patch validates that the lengths of the property arrays are the
> same. If there is a mismatch, the patch will ensure that we bail out
> and not expose the platform idle states via cpuidle.
>
> Signed-off-by: Gautham R. Shenoy <e...@linux.vnet.ibm.com>
> ---
> v1: https://lkml.org/lkml/2017/2/23/349
> Changes from v1: Print the full property array name in warning message.
Reviewed-by: Shilpasri G Bhat <shilpa.b...@linux.vnet.ibm.com>
>
> drivers/cpuidle/cpuidle-powernv.c | 64
> +++++++++++++++++++++++++++++++++++++--
> 1 file changed, 61 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/cpuidle/cpuidle-powernv.c
> b/drivers/cpuidle/cpuidle-powernv.c
> index 3705930..a06df51 100644
> --- a/drivers/cpuidle/cpuidle-powernv.c
> +++ b/drivers/cpuidle/cpuidle-powernv.c
> @@ -197,11 +197,25 @@ static inline void add_powernv_state(int index, const
> char *name,
> stop_psscr_table[index].mask = psscr_mask;
> }
>
> +/*
> + * Returns 0 if prop1_len == prop2_len. Else returns -1
> + */
> +static inline int validate_dt_prop_sizes(const char *prop1, int prop1_len,
> + const char *prop2, int prop2_len)
> +{
> + if (prop1_len == prop2_len)
> + return 0;
> +
> + pr_warn("cpuidle-powernv: array sizes don't match for %s and %s\n",
> + prop1, prop2);
> + return -1;
> +}
> +
> static int powernv_add_idle_states(void)
> {
> struct device_node *power_mgt;
> int nr_idle_states = 1; /* Snooze */
> - int dt_idle_states;
> + int dt_idle_states, count;
> u32 latency_ns[CPUIDLE_STATE_MAX];
> u32 residency_ns[CPUIDLE_STATE_MAX];
> u32 flags[CPUIDLE_STATE_MAX];
> @@ -226,6 +240,21 @@ static int powernv_add_idle_states(void)
> goto out;
> }
>
> + count = of_property_count_u32_elems(power_mgt,
> + "ibm,cpu-idle-state-latencies-ns");
> +
> + if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags", dt_idle_states,
> + "ibm,cpu-idle-state-latencies-ns",
> + count) != 0)
> + goto out;
> +
> + count = of_property_count_strings(power_mgt,
> + "ibm,cpu-idle-state-names");
> + if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags", dt_idle_states,
> + "ibm,cpu-idle-state-names",
> + count) != 0)
> + goto out;
> +
> /*
> * Since snooze is used as first idle state, max idle states allowed is
> * CPUIDLE_STATE_MAX -1
> @@ -260,6 +289,22 @@ static int powernv_add_idle_states(void)
> has_stop_states = (flags[0] &
> (OPAL_PM_STOP_INST_FAST | OPAL_PM_STOP_INST_DEEP));
> if (has_stop_states) {
> + count = of_property_count_u64_elems(power_mgt,
> + "ibm,cpu-idle-state-psscr");
> + if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags",
> + dt_idle_states,
> + "ibm,cpu-idle-state-psscr",
> + count) != 0)
> + goto out;
> +
> + count = of_property_count_u64_elems(power_mgt,
> +
> "ibm,cpu-idle-state-psscr-mask");
> + if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags",
> + dt_idle_states,
> + "ibm,cpu-idle-state-psscr-mask",
> + count) != 0)
> + goto out;
> +
> if (of_property_read_u64_array(power_mgt,
> "ibm,cpu-idle-state-psscr", psscr_val, dt_idle_states)) {
> pr_warn("cpuidle-powernv: missing
> ibm,cpu-idle-state-psscr in DT\n");
> @@ -274,8 +319,21 @@ static int powernv_add_idle_states(void)
> }
> }
>
> - rc = of_property_read_u32_array(power_mgt,
> - "ibm,cpu-idle-state-residency-ns", residency_ns,
> dt_idle_states);
> + count = of_property_count_u32_elems(power_mgt,
> + "ibm,cpu-idle-state-residency-ns");
> +
> + if (count < 0) {
> + rc = count;
> + } else if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags",
> + dt_idle_states,
> + "ibm,cpu-idle-state-residency-ns",
> + count) != 0) {
> + goto out;
> + } else {
> + rc = of_property_read_u32_array(power_mgt,
> +
> "ibm,cpu-idle-state-residency-ns",
> + residency_ns, dt_idle_states);
> + }
>
> for (i = 0; i < dt_idle_states; i++) {
> unsigned int exit_latency, target_residency;
>
