cregit-Linux how code gets into the kernel

Release 4.7 drivers/firmware/psci.c

Directory: drivers/firmware
/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * Copyright (C) 2015 ARM Limited
 */


#define pr_fmt(fmt) "psci: " fmt

#include <linux/arm-smccc.h>
#include <linux/cpuidle.h>
#include <linux/errno.h>
#include <linux/linkage.h>
#include <linux/of.h>
#include <linux/pm.h>
#include <linux/printk.h>
#include <linux/psci.h>
#include <linux/reboot.h>
#include <linux/slab.h>
#include <linux/suspend.h>

#include <uapi/linux/psci.h>

#include <asm/cpuidle.h>
#include <asm/cputype.h>
#include <asm/system_misc.h>
#include <asm/smp_plat.h>
#include <asm/suspend.h>

/*
 * While a 64-bit OS can make calls with SMC32 calling conventions, for some
 * calls it is necessary to use SMC64 to pass or return 64-bit values.
 * For such calls PSCI_FN_NATIVE(version, name) will choose the appropriate
 * (native-width) function ID.
 */
#ifdef CONFIG_64BIT

#define PSCI_FN_NATIVE(version, name)	PSCI_##version##_FN64_##name
#else

#define PSCI_FN_NATIVE(version, name)	PSCI_##version##_FN_##name
#endif

/*
 * The CPU any Trusted OS is resident on. The trusted OS may reject CPU_OFF
 * calls to its resident CPU, so we must avoid issuing those. We never migrate
 * a Trusted OS even if it claims to be capable of migration -- doing so will
 * require cooperation with a Trusted OS driver.
 */

static int resident_cpu = -1;


bool psci_tos_resident_on(int cpu) { return cpu == resident_cpu; }

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struct psci_operations psci_ops; typedef unsigned long (psci_fn)(unsigned long, unsigned long, unsigned long, unsigned long); static psci_fn *invoke_psci_fn; enum psci_function { PSCI_FN_CPU_SUSPEND, PSCI_FN_CPU_ON, PSCI_FN_CPU_OFF, PSCI_FN_MIGRATE, PSCI_FN_MAX, }; static u32 psci_function_id[PSCI_FN_MAX]; #define PSCI_0_2_POWER_STATE_MASK \ (PSCI_0_2_POWER_STATE_ID_MASK | \ PSCI_0_2_POWER_STATE_TYPE_MASK | \ PSCI_0_2_POWER_STATE_AFFL_MASK) #define PSCI_1_0_EXT_POWER_STATE_MASK \ (PSCI_1_0_EXT_POWER_STATE_ID_MASK | \ PSCI_1_0_EXT_POWER_STATE_TYPE_MASK) static u32 psci_cpu_suspend_feature;
static inline bool psci_has_ext_power_state(void) { return psci_cpu_suspend_feature & PSCI_1_0_FEATURES_CPU_SUSPEND_PF_MASK; }

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static inline bool psci_power_state_loses_context(u32 state) { const u32 mask = psci_has_ext_power_state() ? PSCI_1_0_EXT_POWER_STATE_TYPE_MASK : PSCI_0_2_POWER_STATE_TYPE_MASK; return state & mask; }

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static inline bool psci_power_state_is_valid(u32 state) { const u32 valid_mask = psci_has_ext_power_state() ? PSCI_1_0_EXT_POWER_STATE_MASK : PSCI_0_2_POWER_STATE_MASK; return !(state & ~valid_mask); }

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static unsigned long __invoke_psci_fn_hvc(unsigned long function_id, unsigned long arg0, unsigned long arg1, unsigned long arg2) { struct arm_smccc_res res; arm_smccc_hvc(function_id, arg0, arg1, arg2, 0, 0, 0, 0, &res); return res.a0; }

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static unsigned long __invoke_psci_fn_smc(unsigned long function_id, unsigned long arg0, unsigned long arg1, unsigned long arg2) { struct arm_smccc_res res; arm_smccc_smc(function_id, arg0, arg1, arg2, 0, 0, 0, 0, &res); return res.a0; }

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static int psci_to_linux_errno(int errno) { switch (errno) { case PSCI_RET_SUCCESS: return 0; case PSCI_RET_NOT_SUPPORTED: return -EOPNOTSUPP; case PSCI_RET_INVALID_PARAMS: case PSCI_RET_INVALID_ADDRESS: return -EINVAL; case PSCI_RET_DENIED: return -EPERM; }; return -EINVAL; }

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static u32 psci_get_version(void) { return invoke_psci_fn(PSCI_0_2_FN_PSCI_VERSION, 0, 0, 0); }

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static int psci_cpu_suspend(u32 state, unsigned long entry_point) { int err; u32 fn; fn = psci_function_id[PSCI_FN_CPU_SUSPEND]; err = invoke_psci_fn(fn, state, entry_point, 0); return psci_to_linux_errno(err); }

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static int psci_cpu_off(u32 state) { int err; u32 fn; fn = psci_function_id[PSCI_FN_CPU_OFF]; err = invoke_psci_fn(fn, state, 0, 0); return psci_to_linux_errno(err); }

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static int psci_cpu_on(unsigned long cpuid, unsigned long entry_point) { int err; u32 fn; fn = psci_function_id[PSCI_FN_CPU_ON]; err = invoke_psci_fn(fn, cpuid, entry_point, 0); return psci_to_linux_errno(err); }

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static int psci_migrate(unsigned long cpuid) { int err; u32 fn; fn = psci_function_id[PSCI_FN_MIGRATE]; err = invoke_psci_fn(fn, cpuid, 0, 0); return psci_to_linux_errno(err); }

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static int psci_affinity_info(unsigned long target_affinity, unsigned long lowest_affinity_level) { return invoke_psci_fn(PSCI_FN_NATIVE(0_2, AFFINITY_INFO), target_affinity, lowest_affinity_level, 0); }

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static int psci_migrate_info_type(void) { return invoke_psci_fn(PSCI_0_2_FN_MIGRATE_INFO_TYPE, 0, 0, 0); }

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static unsigned long psci_migrate_info_up_cpu(void) { return invoke_psci_fn(PSCI_FN_NATIVE(0_2, MIGRATE_INFO_UP_CPU), 0, 0, 0); }

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static int get_set_conduit_method(struct device_node *np) { const char *method; pr_info("probing for conduit method from DT.\n"); if (of_property_read_string(np, "method", &method)) { pr_warn("missing \"method\" property\n"); return -ENXIO; } if (!strcmp("hvc", method)) { invoke_psci_fn = __invoke_psci_fn_hvc; } else if (!strcmp("smc", method)) { invoke_psci_fn = __invoke_psci_fn_smc; } else { pr_warn("invalid \"method\" property: %s\n", method); return -EINVAL; } return 0; }

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static void psci_sys_reset(enum reboot_mode reboot_mode, const char *cmd) { invoke_psci_fn(PSCI_0_2_FN_SYSTEM_RESET, 0, 0, 0); }

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static void psci_sys_poweroff(void) { invoke_psci_fn(PSCI_0_2_FN_SYSTEM_OFF, 0, 0, 0); }

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static int __init psci_features(u32 psci_func_id) { return invoke_psci_fn(PSCI_1_0_FN_PSCI_FEATURES, psci_func_id, 0, 0); }

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#ifdef CONFIG_CPU_IDLE static DEFINE_PER_CPU_READ_MOSTLY(u32 *, psci_power_state);
static int psci_dt_cpu_init_idle(struct device_node *cpu_node, int cpu) { int i, ret, count = 0; u32 *psci_states; struct device_node *state_node; /* * If the PSCI cpu_suspend function hook has not been initialized * idle states must not be enabled, so bail out */ if (!psci_ops.cpu_suspend) return -EOPNOTSUPP; /* Count idle states */ while ((state_node = of_parse_phandle(cpu_node, "cpu-idle-states", count))) { count++; of_node_put(state_node); } if (!count) return -ENODEV; psci_states = kcalloc(count, sizeof(*psci_states), GFP_KERNEL); if (!psci_states) return -ENOMEM; for (i = 0; i < count; i++) { u32 state; state_node = of_parse_phandle(cpu_node, "cpu-idle-states", i); ret = of_property_read_u32(state_node, "arm,psci-suspend-param", &state); if (ret) { pr_warn(" * %s missing arm,psci-suspend-param property\n", state_node->full_name); of_node_put(state_node); goto free_mem; } of_node_put(state_node); pr_debug("psci-power-state %#x index %d\n", state, i); if (!psci_power_state_is_valid(state)) { pr_warn("Invalid PSCI power state %#x\n", state); ret = -EINVAL; goto free_mem; } psci_states[i] = state; } /* Idle states parsed correctly, initialize per-cpu pointer */ per_cpu(psci_power_state, cpu) = psci_states; return 0; free_mem: kfree(psci_states); return ret; }

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int psci_cpu_init_idle(unsigned int cpu) { struct device_node *cpu_node; int ret; cpu_node = of_get_cpu_node(cpu, NULL); if (!cpu_node) return -ENODEV; ret = psci_dt_cpu_init_idle(cpu_node, cpu); of_node_put(cpu_node); return ret; }

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static int psci_suspend_finisher(unsigned long index) { u32 *state = __this_cpu_read(psci_power_state); return psci_ops.cpu_suspend(state[index - 1], virt_to_phys(cpu_resume)); }

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int psci_cpu_suspend_enter(unsigned long index) { int ret; u32 *state = __this_cpu_read(psci_power_state); /* * idle state index 0 corresponds to wfi, should never be called * from the cpu_suspend operations */ if (WARN_ON_ONCE(!index)) return -EINVAL; if (!psci_power_state_loses_context(state[index - 1])) ret = psci_ops.cpu_suspend(state[index - 1], 0); else ret = cpu_suspend(index, psci_suspend_finisher); return ret; }

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/* ARM specific CPU idle operations */ #ifdef CONFIG_ARM static const struct cpuidle_ops psci_cpuidle_ops __initconst = { .suspend = psci_cpu_suspend_enter, .init = psci_dt_cpu_init_idle, }; CPUIDLE_METHOD_OF_DECLARE(psci, "psci", &psci_cpuidle_ops); #endif #endif
static int psci_system_suspend(unsigned long unused) { return invoke_psci_fn(PSCI_FN_NATIVE(1_0, SYSTEM_SUSPEND), virt_to_phys(cpu_resume), 0, 0); }

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static int psci_system_suspend_enter(suspend_state_t state) { return cpu_suspend(0, psci_system_suspend); }

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static const struct platform_suspend_ops psci_suspend_ops = { .valid = suspend_valid_only_mem, .enter = psci_system_suspend_enter, };
static void __init psci_init_system_suspend(void) { int ret; if (!IS_ENABLED(CONFIG_SUSPEND)) return; ret = psci_features(PSCI_FN_NATIVE(1_0, SYSTEM_SUSPEND)); if (ret != PSCI_RET_NOT_SUPPORTED) suspend_set_ops(&psci_suspend_ops); }

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static void __init psci_init_cpu_suspend(void) { int feature = psci_features(psci_function_id[PSCI_FN_CPU_SUSPEND]); if (feature != PSCI_RET_NOT_SUPPORTED) psci_cpu_suspend_feature = feature; }

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/* * Detect the presence of a resident Trusted OS which may cause CPU_OFF to * return DENIED (which would be fatal). */
static void __init psci_init_migrate(void) { unsigned long cpuid; int type, cpu = -1; type = psci_ops.migrate_info_type(); if (type == PSCI_0_2_TOS_MP) { pr_info("Trusted OS migration not required\n"); return; } if (type == PSCI_RET_NOT_SUPPORTED) { pr_info("MIGRATE_INFO_TYPE not supported.\n"); return; } if (type != PSCI_0_2_TOS_UP_MIGRATE && type != PSCI_0_2_TOS_UP_NO_MIGRATE) { pr_err("MIGRATE_INFO_TYPE returned unknown type (%d)\n", type); return; } cpuid = psci_migrate_info_up_cpu(); if (cpuid & ~MPIDR_HWID_BITMASK) { pr_warn("MIGRATE_INFO_UP_CPU reported invalid physical ID (0x%lx)\n", cpuid); return; } cpu = get_logical_index(cpuid); resident_cpu = cpu >= 0 ? cpu : -1; pr_info("Trusted OS resident on physical CPU 0x%lx\n", cpuid); }

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static void __init psci_0_2_set_functions(void) { pr_info("Using standard PSCI v0.2 function IDs\n"); psci_function_id[PSCI_FN_CPU_SUSPEND] = PSCI_FN_NATIVE(0_2, CPU_SUSPEND); psci_ops.cpu_suspend = psci_cpu_suspend; psci_function_id[PSCI_FN_CPU_OFF] = PSCI_0_2_FN_CPU_OFF; psci_ops.cpu_off = psci_cpu_off; psci_function_id[PSCI_FN_CPU_ON] = PSCI_FN_NATIVE(0_2, CPU_ON); psci_ops.cpu_on = psci_cpu_on; psci_function_id[PSCI_FN_MIGRATE] = PSCI_FN_NATIVE(0_2, MIGRATE); psci_ops.migrate = psci_migrate; psci_ops.affinity_info = psci_affinity_info; psci_ops.migrate_info_type = psci_migrate_info_type; arm_pm_restart = psci_sys_reset; pm_power_off = psci_sys_poweroff; }

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/* * Probe function for PSCI firmware versions >= 0.2 */
static int __init psci_probe(void) { u32 ver = psci_get_version(); pr_info("PSCIv%d.%d detected in firmware.\n", PSCI_VERSION_MAJOR(ver), PSCI_VERSION_MINOR(ver)); if (PSCI_VERSION_MAJOR(ver) == 0 && PSCI_VERSION_MINOR(ver) < 2) { pr_err("Conflicting PSCI version detected.\n"); return -EINVAL; } psci_0_2_set_functions(); psci_init_migrate(); if (PSCI_VERSION_MAJOR(ver) >= 1) { psci_init_cpu_suspend(); psci_init_system_suspend(); } return 0; }

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typedef int (*psci_initcall_t)(const struct device_node *); /* * PSCI init function for PSCI versions >=0.2 * * Probe based on PSCI PSCI_VERSION function */
static int __init psci_0_2_init(struct device_node *np) { int err; err = get_set_conduit_method(np); if (err) goto out_put_node; /* * Starting with v0.2, the PSCI specification introduced a call * (PSCI_VERSION) that allows probing the firmware version, so * that PSCI function IDs and version specific initialization * can be carried out according to the specific version reported * by firmware */ err = psci_probe(); out_put_node: of_node_put(np); return err; }

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/* * PSCI < v0.2 get PSCI Function IDs via DT. */
static int __init psci_0_1_init(struct device_node *np) { u32 id; int err; err = get_set_conduit_method(np); if (err) goto out_put_node; pr_info("Using PSCI v0.1 Function IDs from DT\n"); if (!of_property_read_u32(np, "cpu_suspend", &id)) { psci_function_id[PSCI_FN_CPU_SUSPEND] = id; psci_ops.cpu_suspend = psci_cpu_suspend; } if (!of_property_read_u32(np, "cpu_off", &id)) { psci_function_id[PSCI_FN_CPU_OFF] = id; psci_ops.cpu_off = psci_cpu_off; } if (!of_property_read_u32(np, "cpu_on", &id)) { psci_function_id[PSCI_FN_CPU_ON] = id; psci_ops.cpu_on = psci_cpu_on; } if (!of_property_read_u32(np, "migrate", &id)) { psci_function_id[PSCI_FN_MIGRATE] = id; psci_ops.migrate = psci_migrate; } out_put_node: of_node_put(np); return err; }

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static const struct of_device_id psci_of_match[] __initconst = { { .compatible = "arm,psci", .data = psci_0_1_init}, { .compatible = "arm,psci-0.2", .data = psci_0_2_init}, { .compatible = "arm,psci-1.0", .data = psci_0_2_init}, {}, };
int __init psci_dt_init(void) { struct device_node *np; const struct of_device_id *matched_np; psci_initcall_t init_fn; np = of_find_matching_node_and_match(NULL, psci_of_match, &matched_np); if (!np) return -ENODEV; init_fn = (psci_initcall_t)matched_np->data; return init_fn(np); }

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#ifdef CONFIG_ACPI /* * We use PSCI 0.2+ when ACPI is deployed on ARM64 and it's * explicitly clarified in SBBR */
int __init psci_acpi_init(void) { if (!acpi_psci_present()) { pr_info("is not implemented in ACPI.\n"); return -EOPNOTSUPP; } pr_info("probing for conduit method from ACPI.\n"); if (acpi_psci_use_hvc()) invoke_psci_fn = __invoke_psci_fn_hvc; else invoke_psci_fn = __invoke_psci_fn_smc; return psci_probe(); }

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#endif

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Directory: drivers/firmware
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