arch/riscv/kernel/pi/cmdline_early.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 #include <linux/types.h>
   3 #include <linux/init.h>
   4 #include <linux/libfdt.h>
   5 #include <linux/string.h>
   6 #include <asm/pgtable.h>
   7 #include <asm/setup.h>
   8
   9 static char early_cmdline[COMMAND_LINE_SIZE];
  10
  11 /*
  12  * Declare the functions that are exported (but prefixed) here so that LLVM
  13  * does not complain it lacks the 'static' keyword (which, if added, makes
  14  * LLVM complain because the function is actually unused in this file).
  15  */
  16 u64 set_satp_mode_from_cmdline(uintptr_t dtb_pa);
  17 bool set_nokaslr_from_cmdline(uintptr_t dtb_pa);
  18
  19 static char *get_early_cmdline(uintptr_t dtb_pa)
  20 {
  21         const char *fdt_cmdline = NULL;
  22         unsigned int fdt_cmdline_size = 0;
  23         int chosen_node;
  24
  25         if (!IS_ENABLED(CONFIG_CMDLINE_FORCE)) {
  26                 chosen_node = fdt_path_offset((void *)dtb_pa, "/chosen");
  27                 if (chosen_node >= 0) {
  28                         fdt_cmdline = fdt_getprop((void *)dtb_pa, chosen_node,
  29                                                   "bootargs", NULL);
  30                         if (fdt_cmdline) {
  31                                 fdt_cmdline_size = strlen(fdt_cmdline);
  32                                 strscpy(early_cmdline, fdt_cmdline,
  33                                         COMMAND_LINE_SIZE);
  34                         }
  35                 }
  36         }
  37
  38         if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) ||
  39             IS_ENABLED(CONFIG_CMDLINE_FORCE) ||
  40             fdt_cmdline_size == 0 /* CONFIG_CMDLINE_FALLBACK */) {
  41                 strncat(early_cmdline, CONFIG_CMDLINE,
  42                         COMMAND_LINE_SIZE - fdt_cmdline_size);
  43         }
  44
  45         return early_cmdline;
  46 }
  47
  48 static u64 match_noXlvl(char *cmdline)
  49 {
  50         if (strstr(cmdline, "no4lvl"))
  51                 return SATP_MODE_48;
  52         else if (strstr(cmdline, "no5lvl"))
  53                 return SATP_MODE_57;
  54
  55         return 0;
  56 }
  57
  58 u64 set_satp_mode_from_cmdline(uintptr_t dtb_pa)
  59 {
  60         char *cmdline = get_early_cmdline(dtb_pa);
  61
  62         return match_noXlvl(cmdline);
  63 }
  64
  65 static bool match_nokaslr(char *cmdline)
  66 {
  67         return strstr(cmdline, "nokaslr");
  68 }
  69
  70 bool set_nokaslr_from_cmdline(uintptr_t dtb_pa)
  71 {
  72         char *cmdline = get_early_cmdline(dtb_pa);
  73
  74         return match_nokaslr(cmdline);
  75 }