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