arch/s390/kernel/abs_lowcore.c

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 #include <linux/pgtable.h>
   4 #include <asm/abs_lowcore.h>
   5
   6 unsigned long __bootdata_preserved(__abs_lowcore);
   7 int __bootdata_preserved(relocate_lowcore);
   8
   9 int abs_lowcore_map(int cpu, struct lowcore *lc, bool alloc)
  10 {
  11         unsigned long addr = __abs_lowcore + (cpu * sizeof(struct lowcore));
  12         unsigned long phys = __pa(lc);
  13         int rc, i;
  14
  15         for (i = 0; i < LC_PAGES; i++) {
  16                 rc = __vmem_map_4k_page(addr, phys, PAGE_KERNEL, alloc);
  17                 if (rc) {
  18                         /*
  19                          * Do not unmap allocated page tables in case the
  20                          * allocation was not requested. In such a case the
  21                          * request is expected coming from an atomic context,
  22                          * while the unmap attempt might sleep.
  23                          */
  24                         if (alloc) {
  25                                 for (--i; i >= 0; i--) {
  26                                         addr -= PAGE_SIZE;
  27                                         vmem_unmap_4k_page(addr);
  28                                 }
  29                         }
  30                         return rc;
  31                 }
  32                 addr += PAGE_SIZE;
  33                 phys += PAGE_SIZE;
  34         }
  35         return 0;
  36 }
  37
  38 void abs_lowcore_unmap(int cpu)
  39 {
  40         unsigned long addr = __abs_lowcore + (cpu * sizeof(struct lowcore));
  41         int i;
  42
  43         for (i = 0; i < LC_PAGES; i++) {
  44                 vmem_unmap_4k_page(addr);
  45                 addr += PAGE_SIZE;
  46         }
  47 }