src/arch/x86/null_breakpoint.c

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2
   3 #include <arch/breakpoint.h>
   4 #include <arch/null_breakpoint.h>
   5 #include <bootstate.h>
   6 #include <console/console.h>
   7 #include <types.h>
   8
   9 static struct breakpoint_handle null_deref_bp;
  10 static struct breakpoint_handle null_fetch_bp;
  11
  12 static int handle_fetch_breakpoint(struct breakpoint_handle handle, struct eregs *regs)
  13 {
  14         printk(BIOS_ERR, "Instruction fetch from address zero\n");
  15         return 0;
  16 }
  17
  18 static int handle_deref_breakpoint(struct breakpoint_handle handle, struct eregs *regs)
  19 {
  20 #if ENV_X86_64
  21         printk(BIOS_ERR, "Null dereference at rip: 0x%llx\n", regs->rip);
  22 #else
  23         printk(BIOS_ERR, "Null dereference at eip: 0x%x\n", regs->eip);
  24 #endif
  25         return 0;
  26 }
  27
  28 static void create_deref_breakpoint(void)
  29 {
  30         enum breakpoint_result res =
  31                 breakpoint_create_data(&null_deref_bp, NULL, sizeof(uintptr_t), false);
  32
  33         if (res != BREAKPOINT_RES_OK) {
  34                 printk(BIOS_ERR, "Failed to create NULL dereference breakpoint\n");
  35                 return;
  36         }
  37
  38         breakpoint_set_handler(null_deref_bp, &handle_deref_breakpoint);
  39         breakpoint_enable(null_deref_bp, true);
  40 }
  41
  42 static void create_instruction_breakpoint(void)
  43 {
  44         enum breakpoint_result res = breakpoint_create_instruction(&null_fetch_bp, NULL);
  45
  46         if (res != BREAKPOINT_RES_OK) {
  47                 printk(BIOS_ERR, "Failed to create address zero instruction fetch breakpoint\n");
  48                 return;
  49         }
  50
  51         breakpoint_set_handler(null_fetch_bp, &handle_fetch_breakpoint);
  52         breakpoint_enable(null_fetch_bp, true);
  53 }
  54
  55 void null_breakpoint_init(void)
  56 {
  57         create_deref_breakpoint();
  58         create_instruction_breakpoint();
  59 }
  60
  61 void null_breakpoint_remove(void)
  62 {
  63         breakpoint_remove(null_fetch_bp);
  64         breakpoint_remove(null_deref_bp);
  65 }
  66
  67 static void null_breakpoint_remove_hook(void *unused)
  68 {
  69         null_breakpoint_remove();
  70 }
  71
  72 BOOT_STATE_INIT_ENTRY(BS_OS_RESUME, BS_ON_ENTRY, null_breakpoint_remove_hook, NULL);
  73 BOOT_STATE_INIT_ENTRY(BS_PAYLOAD_BOOT, BS_ON_ENTRY, null_breakpoint_remove_hook, NULL);