[PATCH] firmware/psci: Add debugfs support to ease debugging
Dmitry Baryshkov
dmitry.baryshkov at linaro.org
Wed Jul 27 13:56:32 PDT 2022
On Wed, 27 Jul 2022 at 23:55, Bhupesh Sharma <bhupesh.sharma at linaro.org> wrote:
>
>
>
> On 7/28/22 2:23 AM, Dmitry Baryshkov wrote:
> > On Wed, 27 Jul 2022 at 23:15, Bhupesh Sharma <bhupesh.sharma at linaro.org> 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 at linaro.org>
> >>> ---
> >>> 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?
>
> 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
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