From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- drivers/cpuidle/cpuidle-pseries.c | 473 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 473 insertions(+) create mode 100644 drivers/cpuidle/cpuidle-pseries.c (limited to 'drivers/cpuidle/cpuidle-pseries.c') diff --git a/drivers/cpuidle/cpuidle-pseries.c b/drivers/cpuidle/cpuidle-pseries.c new file mode 100644 index 000000000..0590001db --- /dev/null +++ b/drivers/cpuidle/cpuidle-pseries.c @@ -0,0 +1,473 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * cpuidle-pseries - idle state cpuidle driver. + * Adapted from drivers/idle/intel_idle.c and + * drivers/acpi/processor_idle.c + * + */ + +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include +#include +#include +#include + +static struct cpuidle_driver pseries_idle_driver = { + .name = "pseries_idle", + .owner = THIS_MODULE, +}; + +static int max_idle_state __read_mostly; +static struct cpuidle_state *cpuidle_state_table __read_mostly; +static u64 snooze_timeout __read_mostly; +static bool snooze_timeout_en __read_mostly; + +static int snooze_loop(struct cpuidle_device *dev, + struct cpuidle_driver *drv, + int index) +{ + u64 snooze_exit_time; + + set_thread_flag(TIF_POLLING_NRFLAG); + + pseries_idle_prolog(); + local_irq_enable(); + snooze_exit_time = get_tb() + snooze_timeout; + + while (!need_resched()) { + HMT_low(); + HMT_very_low(); + if (likely(snooze_timeout_en) && get_tb() > snooze_exit_time) { + /* + * Task has not woken up but we are exiting the polling + * loop anyway. Require a barrier after polling is + * cleared to order subsequent test of need_resched(). + */ + clear_thread_flag(TIF_POLLING_NRFLAG); + smp_mb(); + break; + } + } + + HMT_medium(); + clear_thread_flag(TIF_POLLING_NRFLAG); + + local_irq_disable(); + + pseries_idle_epilog(); + + return index; +} + +static void check_and_cede_processor(void) +{ + /* + * Ensure our interrupt state is properly tracked, + * also checks if no interrupt has occurred while we + * were soft-disabled + */ + if (prep_irq_for_idle()) { + cede_processor(); +#ifdef CONFIG_TRACE_IRQFLAGS + /* Ensure that H_CEDE returns with IRQs on */ + if (WARN_ON(!(mfmsr() & MSR_EE))) + __hard_irq_enable(); +#endif + } +} + +/* + * XCEDE: Extended CEDE states discovered through the + * "ibm,get-systems-parameter" RTAS call with the token + * CEDE_LATENCY_TOKEN + */ + +/* + * Section 7.3.16 System Parameters Option of PAPR version 2.8.1 has a + * table with all the parameters to ibm,get-system-parameters. + * CEDE_LATENCY_TOKEN corresponds to the token value for Cede Latency + * Settings Information. + */ +#define CEDE_LATENCY_TOKEN 45 + +/* + * If the platform supports the cede latency settings information system + * parameter it must provide the following information in the NULL terminated + * parameter string: + * + * a. The first byte is the length “N” of each cede latency setting record minus + * one (zero indicates a length of 1 byte). + * + * b. For each supported cede latency setting a cede latency setting record + * consisting of the first “N” bytes as per the following table. + * + * ----------------------------- + * | Field | Field | + * | Name | Length | + * ----------------------------- + * | Cede Latency | 1 Byte | + * | Specifier Value | | + * ----------------------------- + * | Maximum wakeup | | + * | latency in | 8 Bytes | + * | tb-ticks | | + * ----------------------------- + * | Responsive to | | + * | external | 1 Byte | + * | interrupts | | + * ----------------------------- + * + * This version has cede latency record size = 10. + * + * The structure xcede_latency_payload represents a) and b) with + * xcede_latency_record representing the table in b). + * + * xcede_latency_parameter is what gets returned by + * ibm,get-systems-parameter RTAS call when made with + * CEDE_LATENCY_TOKEN. + * + * These structures are only used to represent the data obtained by the RTAS + * call. The data is in big-endian. + */ +struct xcede_latency_record { + u8 hint; + __be64 latency_ticks; + u8 wake_on_irqs; +} __packed; + +// Make space for 16 records, which "should be enough". +struct xcede_latency_payload { + u8 record_size; + struct xcede_latency_record records[16]; +} __packed; + +struct xcede_latency_parameter { + __be16 payload_size; + struct xcede_latency_payload payload; + u8 null_char; +} __packed; + +static unsigned int nr_xcede_records; +static struct xcede_latency_parameter xcede_latency_parameter __initdata; + +static int __init parse_cede_parameters(void) +{ + struct xcede_latency_payload *payload; + u32 total_xcede_records_size; + u8 xcede_record_size; + u16 payload_size; + int ret, i; + + ret = rtas_call(rtas_token("ibm,get-system-parameter"), 3, 1, + NULL, CEDE_LATENCY_TOKEN, __pa(&xcede_latency_parameter), + sizeof(xcede_latency_parameter)); + if (ret) { + pr_err("xcede: Error parsing CEDE_LATENCY_TOKEN\n"); + return ret; + } + + payload_size = be16_to_cpu(xcede_latency_parameter.payload_size); + payload = &xcede_latency_parameter.payload; + + xcede_record_size = payload->record_size + 1; + + if (xcede_record_size != sizeof(struct xcede_latency_record)) { + pr_err("xcede: Expected record-size %lu. Observed size %u.\n", + sizeof(struct xcede_latency_record), xcede_record_size); + return -EINVAL; + } + + pr_info("xcede: xcede_record_size = %d\n", xcede_record_size); + + /* + * Since the payload_size includes the last NULL byte and the + * xcede_record_size, the remaining bytes correspond to array of all + * cede_latency settings. + */ + total_xcede_records_size = payload_size - 2; + nr_xcede_records = total_xcede_records_size / xcede_record_size; + + for (i = 0; i < nr_xcede_records; i++) { + struct xcede_latency_record *record = &payload->records[i]; + u64 latency_ticks = be64_to_cpu(record->latency_ticks); + u8 wake_on_irqs = record->wake_on_irqs; + u8 hint = record->hint; + + pr_info("xcede: Record %d : hint = %u, latency = 0x%llx tb ticks, Wake-on-irq = %u\n", + i, hint, latency_ticks, wake_on_irqs); + } + + return 0; +} + +#define NR_DEDICATED_STATES 2 /* snooze, CEDE */ +static u8 cede_latency_hint[NR_DEDICATED_STATES]; + +static int dedicated_cede_loop(struct cpuidle_device *dev, + struct cpuidle_driver *drv, + int index) +{ + u8 old_latency_hint; + + pseries_idle_prolog(); + get_lppaca()->donate_dedicated_cpu = 1; + old_latency_hint = get_lppaca()->cede_latency_hint; + get_lppaca()->cede_latency_hint = cede_latency_hint[index]; + + HMT_medium(); + check_and_cede_processor(); + + local_irq_disable(); + get_lppaca()->donate_dedicated_cpu = 0; + get_lppaca()->cede_latency_hint = old_latency_hint; + + pseries_idle_epilog(); + + return index; +} + +static int shared_cede_loop(struct cpuidle_device *dev, + struct cpuidle_driver *drv, + int index) +{ + + pseries_idle_prolog(); + + /* + * Yield the processor to the hypervisor. We return if + * an external interrupt occurs (which are driven prior + * to returning here) or if a prod occurs from another + * processor. When returning here, external interrupts + * are enabled. + */ + check_and_cede_processor(); + + local_irq_disable(); + pseries_idle_epilog(); + + return index; +} + +/* + * States for dedicated partition case. + */ +static struct cpuidle_state dedicated_states[NR_DEDICATED_STATES] = { + { /* Snooze */ + .name = "snooze", + .desc = "snooze", + .exit_latency = 0, + .target_residency = 0, + .enter = &snooze_loop }, + { /* CEDE */ + .name = "CEDE", + .desc = "CEDE", + .exit_latency = 10, + .target_residency = 100, + .enter = &dedicated_cede_loop }, +}; + +/* + * States for shared partition case. + */ +static struct cpuidle_state shared_states[] = { + { /* Snooze */ + .name = "snooze", + .desc = "snooze", + .exit_latency = 0, + .target_residency = 0, + .enter = &snooze_loop }, + { /* Shared Cede */ + .name = "Shared Cede", + .desc = "Shared Cede", + .exit_latency = 10, + .target_residency = 100, + .enter = &shared_cede_loop }, +}; + +static int pseries_cpuidle_cpu_online(unsigned int cpu) +{ + struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu); + + if (dev && cpuidle_get_driver()) { + cpuidle_pause_and_lock(); + cpuidle_enable_device(dev); + cpuidle_resume_and_unlock(); + } + return 0; +} + +static int pseries_cpuidle_cpu_dead(unsigned int cpu) +{ + struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu); + + if (dev && cpuidle_get_driver()) { + cpuidle_pause_and_lock(); + cpuidle_disable_device(dev); + cpuidle_resume_and_unlock(); + } + return 0; +} + +/* + * pseries_cpuidle_driver_init() + */ +static int pseries_cpuidle_driver_init(void) +{ + int idle_state; + struct cpuidle_driver *drv = &pseries_idle_driver; + + drv->state_count = 0; + + for (idle_state = 0; idle_state < max_idle_state; ++idle_state) { + /* Is the state not enabled? */ + if (cpuidle_state_table[idle_state].enter == NULL) + continue; + + drv->states[drv->state_count] = /* structure copy */ + cpuidle_state_table[idle_state]; + + drv->state_count += 1; + } + + return 0; +} + +static void __init fixup_cede0_latency(void) +{ + struct xcede_latency_payload *payload; + u64 min_xcede_latency_us = UINT_MAX; + int i; + + if (parse_cede_parameters()) + return; + + pr_info("cpuidle: Skipping the %d Extended CEDE idle states\n", + nr_xcede_records); + + payload = &xcede_latency_parameter.payload; + + /* + * The CEDE idle state maps to CEDE(0). While the hypervisor + * does not advertise CEDE(0) exit latency values, it does + * advertise the latency values of the extended CEDE states. + * We use the lowest advertised exit latency value as a proxy + * for the exit latency of CEDE(0). + */ + for (i = 0; i < nr_xcede_records; i++) { + struct xcede_latency_record *record = &payload->records[i]; + u8 hint = record->hint; + u64 latency_tb = be64_to_cpu(record->latency_ticks); + u64 latency_us = DIV_ROUND_UP_ULL(tb_to_ns(latency_tb), NSEC_PER_USEC); + + /* + * We expect the exit latency of an extended CEDE + * state to be non-zero, it to since it takes at least + * a few nanoseconds to wakeup the idle CPU and + * dispatch the virtual processor into the Linux + * Guest. + * + * So we consider only non-zero value for performing + * the fixup of CEDE(0) latency. + */ + if (latency_us == 0) { + pr_warn("cpuidle: Skipping xcede record %d [hint=%d]. Exit latency = 0us\n", + i, hint); + continue; + } + + if (latency_us < min_xcede_latency_us) + min_xcede_latency_us = latency_us; + } + + if (min_xcede_latency_us != UINT_MAX) { + dedicated_states[1].exit_latency = min_xcede_latency_us; + dedicated_states[1].target_residency = 10 * (min_xcede_latency_us); + pr_info("cpuidle: Fixed up CEDE exit latency to %llu us\n", + min_xcede_latency_us); + } + +} + +/* + * pseries_idle_probe() + * Choose state table for shared versus dedicated partition + */ +static int __init pseries_idle_probe(void) +{ + + if (cpuidle_disable != IDLE_NO_OVERRIDE) + return -ENODEV; + + if (firmware_has_feature(FW_FEATURE_SPLPAR)) { + if (lppaca_shared_proc()) { + cpuidle_state_table = shared_states; + max_idle_state = ARRAY_SIZE(shared_states); + } else { + /* + * Use firmware provided latency values + * starting with POWER10 platforms. In the + * case that we are running on a POWER10 + * platform but in an earlier compat mode, we + * can still use the firmware provided values. + * + * However, on platforms prior to POWER10, we + * cannot rely on the accuracy of the firmware + * provided latency values. On such platforms, + * go with the conservative default estimate + * of 10us. + */ + if (cpu_has_feature(CPU_FTR_ARCH_31) || pvr_version_is(PVR_POWER10)) + fixup_cede0_latency(); + cpuidle_state_table = dedicated_states; + max_idle_state = NR_DEDICATED_STATES; + } + } else + return -ENODEV; + + if (max_idle_state > 1) { + snooze_timeout_en = true; + snooze_timeout = cpuidle_state_table[1].target_residency * + tb_ticks_per_usec; + } + return 0; +} + +static int __init pseries_processor_idle_init(void) +{ + int retval; + + retval = pseries_idle_probe(); + if (retval) + return retval; + + pseries_cpuidle_driver_init(); + retval = cpuidle_register(&pseries_idle_driver, NULL); + if (retval) { + printk(KERN_DEBUG "Registration of pseries driver failed.\n"); + return retval; + } + + retval = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, + "cpuidle/pseries:online", + pseries_cpuidle_cpu_online, NULL); + WARN_ON(retval < 0); + retval = cpuhp_setup_state_nocalls(CPUHP_CPUIDLE_DEAD, + "cpuidle/pseries:DEAD", NULL, + pseries_cpuidle_cpu_dead); + WARN_ON(retval < 0); + printk(KERN_DEBUG "pseries_idle_driver registered\n"); + return 0; +} + +device_initcall(pseries_processor_idle_init); -- cgit v1.2.3