On Thu, Aug 04, 2022 at 04:15:07PM +0300, 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>
> ---
> Changes since v1:
> - Extended the table to include MEM_PROTECT functions (noted by Mark
> Brown)
> - Switched to seq_puts where possible
> - Changed S_IRUGO to 0444
> ---
> drivers/firmware/psci/psci.c | 116 ++++++++++++++++++++++++++++++++++-
> include/uapi/linux/psci.h | 14 +++++
> 2 files changed, 129 insertions(+), 1 deletion(-)
TBH I am really not keen on exposing this to userspace. AFAICT this is his is
incredibly niche, and is going to be very painful to maintain.
Without a strong rationale, I do not thing we should do this.
Who is going to use this, and when?
I'd be much happier logging stuff as it's probed into dmesg; I'm happy to add
more information there (and/or a command line parameter to be more verbose).
Thanks,
Mark.
>
> diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c
> index 1628f1edef4a..42cae0ba10e2 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>
> @@ -326,12 +327,125 @@ 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)
> {
> 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),
> + PSCI_ID(1_1, MEM_PROTECT),
> + PSCI_ID_NATIVE(1_1, MEM_PROTECT_CHECK_RANGE),
> +};
> +
> +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_puts(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_puts(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", 0444, 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..3511095c2702 100644
> --- a/include/uapi/linux/psci.h
> +++ b/include/uapi/linux/psci.h
> @@ -48,12 +48,26 @@
> #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_1_FN_MEM_PROTECT PSCI_0_2_FN(19)
> +#define PSCI_1_1_FN_MEM_PROTECT_CHECK_RANGE PSCI_0_2_FN(19)
>
> +#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)
> +#define PSCI_1_1_FN64_MEM_PROTECT_CHECK_RANGE PSCI_0_2_FN64(19)
>
> /* PSCI v0.2 power state encoding for CPU_SUSPEND function */
> #define PSCI_0_2_POWER_STATE_ID_MASK 0xffff
> --
> 2.35.1
>
