// SPDX-License-Identifier: GPL-2.0 /* Copyright (C) 2025 Arm Ltd. */ #include <asm/mpam.h> #include <linux/arm_mpam.h> #include <linux/cpu_pm.h> #include <linux/jump_label.h> #include <linux/percpu.h> DEFINE_STATIC_KEY_FALSE(mpam_enabled); DEFINE_PER_CPU(u64, arm64_mpam_default); DEFINE_PER_CPU(u64, arm64_mpam_current); u64 arm64_mpam_global_default; static int mpam_pm_notifier(struct notifier_block *self, unsigned long cmd, void *v) { u64 regval; int cpu = smp_processor_id(); switch (cmd) { case CPU_PM_EXIT: /* * Don't use mpam_thread_switch() as the system register * value has changed under our feet. */ regval = READ_ONCE(per_cpu(arm64_mpam_current, cpu)); write_sysreg_s(regval | MPAM1_EL1_MPAMEN, SYS_MPAM1_EL1); if (system_supports_sme()) { write_sysreg_s(regval & (MPAMSM_EL1_PARTID_D | MPAMSM_EL1_PMG_D), SYS_MPAMSM_EL1); } isb(); write_sysreg_s(regval, SYS_MPAM0_EL1); return NOTIFY_OK; default: return NOTIFY_DONE; } } static struct notifier_block mpam_pm_nb = { .notifier_call = mpam_pm_notifier, }; static int __init arm64_mpam_register_cpus(void) { u64 mpamidr = read_sanitised_ftr_reg(SYS_MPAMIDR_EL1); u16 partid_max = FIELD_GET(MPAMIDR_EL1_PARTID_MAX, mpamidr); u8 pmg_max = FIELD_GET(MPAMIDR_EL1_PMG_MAX, mpamidr); if (!system_supports_mpam()) return 0; cpu_pm_register_notifier(&mpam_pm_nb); return mpam_register_requestor(partid_max, pmg_max); } /* Must occur before mpam_msc_driver_init() from subsys_initcall() */ arch_initcall(arm64_mpam_register_cpus)