diff options
Diffstat (limited to 'arch/arm64/kernel/mpam.c')
| -rw-r--r-- | arch/arm64/kernel/mpam.c | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/arch/arm64/kernel/mpam.c b/arch/arm64/kernel/mpam.c new file mode 100644 index 000000000000..3a490de4fa12 --- /dev/null +++ b/arch/arm64/kernel/mpam.c @@ -0,0 +1,62 @@ +// 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) |