powerpc/mm/nohash/kup.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * This file contains the routines for initializing kernel userspace protection
   4  */
   5
   6 #include <linux/export.h>
   7 #include <linux/init.h>
   8 #include <linux/jump_label.h>
   9 #include <linux/printk.h>
  10 #include <linux/smp.h>
  11
  12 #include <asm/kup.h>
  13 #include <asm/smp.h>
  14
  15 #ifdef CONFIG_PPC_KUAP
  16 struct static_key_false disable_kuap_key;
  17 EXPORT_SYMBOL(disable_kuap_key);
  18
  19 void setup_kuap(bool disabled)
  20 {
  21         if (disabled) {
  22                 if (IS_ENABLED(CONFIG_40x))
  23                         disable_kuep = true;
  24                 if (smp_processor_id() == boot_cpuid)
  25                         static_branch_enable(&disable_kuap_key);
  26                 return;
  27         }
  28
  29         pr_info("Activating Kernel Userspace Access Protection\n");
  30
  31         __prevent_user_access(KUAP_READ_WRITE);
  32 }
  33 #endif