On Wed, 27 Jul 2022 at 23:59, Bhupesh Sharma <bhupesh.sharma@xxxxxxxxxx> wrote:
>
>
>
> On 7/28/22 2:26 AM, Dmitry Baryshkov wrote:
> > On Wed, 27 Jul 2022 at 23:55, Bhupesh Sharma <bhupesh.sharma@xxxxxxxxxx> wrote:
> >>
> >>
> >>
> >> On 7/28/22 2:23 AM, Dmitry Baryshkov wrote:
> >>> On Wed, 27 Jul 2022 at 23:15, Bhupesh Sharma <bhupesh.sharma@xxxxxxxxxx> wrote:
> >>>>
> >>>> Hi Dmitry,
> >>>>
> >>>> On 7/28/22 1:39 AM, Dmitry Baryshkov wrote:
> >>>>> To ease debugging of PSCI supported features, add debugfs file called
> >>>>> 'psci' describing PSCI and SMC CC versions, enabled features and
> >>>>> options.
> >>>>>
> >>>>> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
> >>>>> ---
> >>>>> drivers/firmware/psci/psci.c | 112 ++++++++++++++++++++++++++++++++++-
> >>>>> include/uapi/linux/psci.h | 9 +++
> >>>>> 2 files changed, 120 insertions(+), 1 deletion(-)
> >>>>>
> >>>>> diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c
> >>>>> index b907768eea01..6595cc964635 100644
> >>>>> --- a/drivers/firmware/psci/psci.c
> >>>>> +++ b/drivers/firmware/psci/psci.c
> >>>>> @@ -9,6 +9,7 @@
> >>>>> #include <linux/acpi.h>
> >>>>> #include <linux/arm-smccc.h>
> >>>>> #include <linux/cpuidle.h>
> >>>>> +#include <linux/debugfs.h>
> >>>>> #include <linux/errno.h>
> >>>>> #include <linux/linkage.h>
> >>>>> #include <linux/of.h>
> >>>>> @@ -324,12 +325,121 @@ static void psci_sys_poweroff(void)
> >>>>> invoke_psci_fn(PSCI_0_2_FN_SYSTEM_OFF, 0, 0, 0);
> >>>>> }
> >>>>>
> >>>>> -static int __init psci_features(u32 psci_func_id)
> >>>>> +static int psci_features(u32 psci_func_id)
> >>>>
> >>>> This change doesn't seem related to the patch $SUBJECT.
> >>>> Also is it really needed? If yes, probably this should be a separate patch.
> >>>
> >>> It is related and I don't think it should be moved to a separate
> >>> patch. Removing the __init annotation from psci_features() is
> >>> necessary to allow using psci_features() from psci_debufs_read(),
> >>> which is definitely not an __init code. Otherwise reading from
> >>> debugfs/psci would cause null pointer exceptions.
> >>
> >> Ok, and what is the behavior with CONFIG_DEBUG_FS = n?
> >> Does your patch work well in that case?
> >
> > Yes. Any particular reasons for the question?
>
> Your debugfs changes in this patch are protected with CONFIG_DEBUG_FS,
> while the __init code change is not.
Yes. I'm _removing_ the __init. Making the function available after
kernel frees the __init memory. I'd have understood your questions if
I were making an opposite change, marking the function with __init.
But in this case I doubt it makes any difference.
> So, IMO its not really needed if CONFIG_DEBUG_FS is set to =n (hence
> probably needs to be a separate patch).
An overhead is pretty minimal. And all the troubles to make __init
annotation depend on CONFIG_DEBUG_FS overweight this overhead.
>
> Thanks.
>
> >>>>> {
> >>>>> return invoke_psci_fn(PSCI_1_0_FN_PSCI_FEATURES,
> >>>>> psci_func_id, 0, 0);
> >>>>> }
> >>>>>
> >>>>> +#ifdef CONFIG_DEBUG_FS
> >>>>> +
> >>>>> +#define PSCI_ID(ver, _name) \
> >>>>> + { .fn = PSCI_##ver##_FN_##_name, .name = #_name, }
> >>>>> +#define PSCI_ID_NATIVE(ver, _name) \
> >>>>> + { .fn = PSCI_FN_NATIVE(ver, _name), .name = #_name, }
> >>>>> +
> >>>>> +/* A table of all optional functions */
> >>>>> +static const struct {
> >>>>> + u32 fn;
> >>>>> + const char *name;
> >>>>> +} psci_fn_ids[] = {
> >>>>> + PSCI_ID_NATIVE(0_2, MIGRATE),
> >>>>> + PSCI_ID(0_2, MIGRATE_INFO_TYPE),
> >>>>> + PSCI_ID_NATIVE(0_2, MIGRATE_INFO_UP_CPU),
> >>>>> + PSCI_ID(1_0, CPU_FREEZE),
> >>>>> + PSCI_ID_NATIVE(1_0, CPU_DEFAULT_SUSPEND),
> >>>>> + PSCI_ID_NATIVE(1_0, NODE_HW_STATE),
> >>>>> + PSCI_ID_NATIVE(1_0, SYSTEM_SUSPEND),
> >>>>> + PSCI_ID(1_0, SET_SUSPEND_MODE),
> >>>>> + PSCI_ID_NATIVE(1_0, STAT_RESIDENCY),
> >>>>> + PSCI_ID_NATIVE(1_0, STAT_COUNT),
> >>>>> + PSCI_ID_NATIVE(1_1, SYSTEM_RESET2),
> >>>>> +};
> >>>>> +
> >>>>> +static int psci_debugfs_read(struct seq_file *s, void *data)
> >>>>> +{
> >>>>> + int feature, type, i;
> >>>>> + u32 ver;
> >>>>> +
> >>>>> + ver = psci_ops.get_version();
> >>>>> + seq_printf(s, "PSCIv%d.%d\n",
> >>>>> + PSCI_VERSION_MAJOR(ver),
> >>>>> + PSCI_VERSION_MINOR(ver));
> >>>>> +
> >>>>> + /* PSCI_FEATURES is available only starting from 1.0 */
> >>>>> + if (PSCI_VERSION_MAJOR(ver) < 1)
> >>>>> + return 0;
> >>>>> +
> >>>>> + feature = psci_features(ARM_SMCCC_VERSION_FUNC_ID);
> >>>>> + if (feature != PSCI_RET_NOT_SUPPORTED) {
> >>>>> + ver = invoke_psci_fn(ARM_SMCCC_VERSION_FUNC_ID, 0, 0, 0);
> >>>>> + seq_printf(s, "SMC Calling Convention v%d.%d\n",
> >>>>> + PSCI_VERSION_MAJOR(ver),
> >>>>> + PSCI_VERSION_MINOR(ver));
> >>>>> + } else {
> >>>>> + seq_printf(s, "SMC Calling Convention v1.0 is assumed\n");
> >>>>> + }
> >>>>> +
> >>>>> + feature = psci_features(PSCI_FN_NATIVE(0_2, CPU_SUSPEND));
> >>>>> + if (feature < 0) {
> >>>>> + seq_printf(s, "PSCI_FEATURES(CPU_SUSPEND) error (%d)\n", feature);
> >>>>> + } else {
> >>>>> + seq_printf(s, "OSI is %ssupported\n",
> >>>>> + (feature & BIT(0)) ? "" : "not ");
> >>>>> + seq_printf(s, "%s StateID format is used\n",
> >>>>> + (feature & BIT(1)) ? "Extended" : "Original");
> >>>>> + }
> >>>>> +
> >>>>> + type = psci_ops.migrate_info_type();
> >>>>> + if (type == PSCI_0_2_TOS_UP_MIGRATE ||
> >>>>> + type == PSCI_0_2_TOS_UP_NO_MIGRATE) {
> >>>>> + unsigned long cpuid;
> >>>>> +
> >>>>> + seq_printf(s, "Trusted OS %smigrate capable\n",
> >>>>> + type == PSCI_0_2_TOS_UP_NO_MIGRATE ? "not " : "");
> >>>>> + cpuid = psci_migrate_info_up_cpu();
> >>>>> + seq_printf(s, "Trusted OS resident on physical CPU 0x%lx (#%d)\n", cpuid, resident_cpu);
> >>>>> + } else if (type == PSCI_0_2_TOS_MP) {
> >>>>> + seq_printf(s, "Trusted OS migration not required\n");
> >>>>> + } else {
> >>>>> + if (type != PSCI_RET_NOT_SUPPORTED)
> >>>>> + seq_printf(s, "MIGRATE_INFO_TYPE returned unknown type (%d)\n", type);
> >>>>> + }
> >>>>> +
> >>>>> + for (i = 0; i < ARRAY_SIZE(psci_fn_ids); i++) {
> >>>>> + feature = psci_features(psci_fn_ids[i].fn);
> >>>>> + if (feature == PSCI_RET_NOT_SUPPORTED)
> >>>>> + continue;
> >>>>> + if (feature < 0)
> >>>>> + seq_printf(s, "PSCI_FEATURES(%s) error (%d)\n", psci_fn_ids[i].name, feature);
> >>>>> + else
> >>>>> + seq_printf(s, "%s is supported\n", psci_fn_ids[i].name);
> >>>>> + }
> >>>>> +
> >>>>> + return 0;
> >>>>> +}
> >>>>> +
> >>>>> +static int psci_debugfs_open(struct inode *inode, struct file *f)
> >>>>> +{
> >>>>> + return single_open(f, psci_debugfs_read, NULL);
> >>>>> +}
> >>>>> +
> >>>>> +static const struct file_operations psci_debugfs_ops = {
> >>>>> + .owner = THIS_MODULE,
> >>>>> + .open = psci_debugfs_open,
> >>>>> + .release = single_release,
> >>>>> + .read = seq_read,
> >>>>> + .llseek = seq_lseek
> >>>>> +};
> >>>>> +
> >>>>> +static int __init psci_debugfs_init(void)
> >>>>> +{
> >>>>> + return PTR_ERR_OR_ZERO(debugfs_create_file("psci", S_IRUGO, NULL, NULL,
> >>>>> + &psci_debugfs_ops));
> >>>>> +}
> >>>>> +late_initcall(psci_debugfs_init)
> >>>>> +#endif
> >>>>> +
> >>>>> #ifdef CONFIG_CPU_IDLE
> >>>>> static int psci_suspend_finisher(unsigned long state)
> >>>>> {
> >>>>> diff --git a/include/uapi/linux/psci.h b/include/uapi/linux/psci.h
> >>>>> index 2bf93c0d6354..f6f0bad5858b 100644
> >>>>> --- a/include/uapi/linux/psci.h
> >>>>> +++ b/include/uapi/linux/psci.h
> >>>>> @@ -48,11 +48,20 @@
> >>>>> #define PSCI_0_2_FN64_MIGRATE_INFO_UP_CPU PSCI_0_2_FN64(7)
> >>>>>
> >>>>> #define PSCI_1_0_FN_PSCI_FEATURES PSCI_0_2_FN(10)
> >>>>> +#define PSCI_1_0_FN_CPU_FREEZE PSCI_0_2_FN(11)
> >>>>> +#define PSCI_1_0_FN_CPU_DEFAULT_SUSPEND PSCI_0_2_FN(12)
> >>>>> +#define PSCI_1_0_FN_NODE_HW_STATE PSCI_0_2_FN(13)
> >>>>> #define PSCI_1_0_FN_SYSTEM_SUSPEND PSCI_0_2_FN(14)
> >>>>> #define PSCI_1_0_FN_SET_SUSPEND_MODE PSCI_0_2_FN(15)
> >>>>> +#define PSCI_1_0_FN_STAT_RESIDENCY PSCI_0_2_FN(16)
> >>>>> +#define PSCI_1_0_FN_STAT_COUNT PSCI_0_2_FN(17)
> >>>>> #define PSCI_1_1_FN_SYSTEM_RESET2 PSCI_0_2_FN(18)
> >>>>>
> >>>>> +#define PSCI_1_0_FN64_CPU_DEFAULT_SUSPEND PSCI_0_2_FN64(12)
> >>>>> +#define PSCI_1_0_FN64_NODE_HW_STATE PSCI_0_2_FN64(13)
> >>>>> #define PSCI_1_0_FN64_SYSTEM_SUSPEND PSCI_0_2_FN64(14)
> >>>>> +#define PSCI_1_0_FN64_STAT_RESIDENCY PSCI_0_2_FN64(16)
> >>>>> +#define PSCI_1_0_FN64_STAT_COUNT PSCI_0_2_FN64(17)
> >>>>> #define PSCI_1_1_FN64_SYSTEM_RESET2 PSCI_0_2_FN64(18)
> >>>>>
> >>>>> /* PSCI v0.2 power state encoding for CPU_SUSPEND function */
> >>>
> >>>
> >>>
> >
> >
> >
--
With best wishes
Dmitry
