arch/x86/boot/compressed/idt_64.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 #include <asm/trap_pf.h>
   3 #include <asm/segment.h>
   4 #include <asm/trapnr.h>
   5 #include "misc.h"
   6
   7 static void set_idt_entry(int vector, void (*handler)(void))
   8 {
   9         unsigned long address = (unsigned long)handler;
  10         gate_desc entry;
  11
  12         memset(&entry, 0, sizeof(entry));
  13
  14         entry.offset_low    = (u16)(address & 0xffff);
  15         entry.segment       = __KERNEL_CS;
  16         entry.bits.type     = GATE_TRAP;
  17         entry.bits.p        = 1;
  18         entry.offset_middle = (u16)((address >> 16) & 0xffff);
  19         entry.offset_high   = (u32)(address >> 32);
  20
  21         memcpy(&boot_idt[vector], &entry, sizeof(entry));
  22 }
  23
  24 /* Have this here so we don't need to include <asm/desc.h> */
  25 static void load_boot_idt(const struct desc_ptr *dtr)
  26 {
  27         asm volatile("lidt %0"::"m" (*dtr));
  28 }
  29
  30 /* Setup IDT before kernel jumping to  .Lrelocated */
  31 void load_stage1_idt(void)
  32 {
  33         boot_idt_desc.address = (unsigned long)boot_idt;
  34
  35
  36         if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT))
  37                 set_idt_entry(X86_TRAP_VC, boot_stage1_vc);
  38
  39         load_boot_idt(&boot_idt_desc);
  40 }
  41
  42 /* Setup IDT after kernel jumping to  .Lrelocated */
  43 void load_stage2_idt(void)
  44 {
  45         boot_idt_desc.address = (unsigned long)boot_idt;
  46
  47         set_idt_entry(X86_TRAP_PF, boot_page_fault);
  48
  49 #ifdef CONFIG_AMD_MEM_ENCRYPT
  50         set_idt_entry(X86_TRAP_VC, boot_stage2_vc);
  51 #endif
  52
  53         load_boot_idt(&boot_idt_desc);
  54 }
  55
  56 void cleanup_exception_handling(void)
  57 {
  58         /*
  59          * Flush GHCB from cache and map it encrypted again when running as
  60          * SEV-ES guest.
  61          */
  62         sev_es_shutdown_ghcb();
  63
  64         /* Set a null-idt, disabling #PF and #VC handling */
  65         boot_idt_desc.size    = 0;
  66         boot_idt_desc.address = 0;
  67         load_boot_idt(&boot_idt_desc);
  68 }