arch/riscv/kernel/cpu_ops.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2020 Western Digital Corporation or its affiliates.
   4  */
   5
   6 #include <linux/errno.h>
   7 #include <linux/mm.h>
   8 #include <linux/of.h>
   9 #include <linux/string.h>
  10 #include <linux/sched.h>
  11 #include <linux/sched/task_stack.h>
  12 #include <asm/cpu_ops.h>
  13 #include <asm/sbi.h>
  14 #include <asm/smp.h>
  15
  16 const struct cpu_operations *cpu_ops[NR_CPUS] __ro_after_init;
  17
  18 void *__cpu_up_stack_pointer[NR_CPUS] __section(".data");
  19 void *__cpu_up_task_pointer[NR_CPUS] __section(".data");
  20
  21 extern const struct cpu_operations cpu_ops_sbi;
  22 extern const struct cpu_operations cpu_ops_spinwait;
  23
  24 void cpu_update_secondary_bootdata(unsigned int cpuid,
  25                                    struct task_struct *tidle)
  26 {
  27         int hartid = cpuid_to_hartid_map(cpuid);
  28
  29         /* Make sure tidle is updated */
  30         smp_mb();
  31         WRITE_ONCE(__cpu_up_stack_pointer[hartid],
  32                    task_stack_page(tidle) + THREAD_SIZE);
  33         WRITE_ONCE(__cpu_up_task_pointer[hartid], tidle);
  34 }
  35
  36 void __init cpu_set_ops(int cpuid)
  37 {
  38 #if IS_ENABLED(CONFIG_RISCV_SBI)
  39         if (sbi_probe_extension(SBI_EXT_HSM) > 0) {
  40                 if (!cpuid)
  41                         pr_info("SBI v0.2 HSM extension detected\n");
  42                 cpu_ops[cpuid] = &cpu_ops_sbi;
  43         } else
  44 #endif
  45                 cpu_ops[cpuid] = &cpu_ops_spinwait;
  46 }