Revert "x86-64/efi: Use EFI to deal with platform wall clock (again)"
This reverts commit bd52276fa1d4 ("x86-64/efi: Use EFI to deal with
platform wall clock (again)"), and the two supporting commits:
da5a108d05b4: "x86/kernel: remove tboot 1:1 page table creation code"
185034e72d59: "x86, efi: 1:1 pagetable mapping for virtual EFI calls")
as they all depend semantically on commit 53b87cf088e2 ("x86, mm:
Include the entire kernel memory map in trampoline_pgd") that got
reverted earlier due to the problems it caused.
This was pointed out by Yinghai Lu, and verified by me on my Macbook Air
that uses EFI.
Pointed-out-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c
index d4f460f..f84fe00 100644
--- a/arch/x86/kernel/tboot.c
+++ b/arch/x86/kernel/tboot.c
@@ -103,13 +103,71 @@
pr_debug("tboot_size: 0x%x\n", tboot->tboot_size);
}
+static pgd_t *tboot_pg_dir;
+static struct mm_struct tboot_mm = {
+ .mm_rb = RB_ROOT,
+ .pgd = swapper_pg_dir,
+ .mm_users = ATOMIC_INIT(2),
+ .mm_count = ATOMIC_INIT(1),
+ .mmap_sem = __RWSEM_INITIALIZER(init_mm.mmap_sem),
+ .page_table_lock = __SPIN_LOCK_UNLOCKED(init_mm.page_table_lock),
+ .mmlist = LIST_HEAD_INIT(init_mm.mmlist),
+};
+
static inline void switch_to_tboot_pt(void)
{
-#ifdef CONFIG_X86_32
- load_cr3(initial_page_table);
-#else
- write_cr3(real_mode_header->trampoline_pgd);
-#endif
+ write_cr3(virt_to_phys(tboot_pg_dir));
+}
+
+static int map_tboot_page(unsigned long vaddr, unsigned long pfn,
+ pgprot_t prot)
+{
+ pgd_t *pgd;
+ pud_t *pud;
+ pmd_t *pmd;
+ pte_t *pte;
+
+ pgd = pgd_offset(&tboot_mm, vaddr);
+ pud = pud_alloc(&tboot_mm, pgd, vaddr);
+ if (!pud)
+ return -1;
+ pmd = pmd_alloc(&tboot_mm, pud, vaddr);
+ if (!pmd)
+ return -1;
+ pte = pte_alloc_map(&tboot_mm, NULL, pmd, vaddr);
+ if (!pte)
+ return -1;
+ set_pte_at(&tboot_mm, vaddr, pte, pfn_pte(pfn, prot));
+ pte_unmap(pte);
+ return 0;
+}
+
+static int map_tboot_pages(unsigned long vaddr, unsigned long start_pfn,
+ unsigned long nr)
+{
+ /* Reuse the original kernel mapping */
+ tboot_pg_dir = pgd_alloc(&tboot_mm);
+ if (!tboot_pg_dir)
+ return -1;
+
+ for (; nr > 0; nr--, vaddr += PAGE_SIZE, start_pfn++) {
+ if (map_tboot_page(vaddr, start_pfn, PAGE_KERNEL_EXEC))
+ return -1;
+ }
+
+ return 0;
+}
+
+static void tboot_create_trampoline(void)
+{
+ u32 map_base, map_size;
+
+ /* Create identity map for tboot shutdown code. */
+ map_base = PFN_DOWN(tboot->tboot_base);
+ map_size = PFN_UP(tboot->tboot_size);
+ if (map_tboot_pages(map_base << PAGE_SHIFT, map_base, map_size))
+ panic("tboot: Error mapping tboot pages (mfns) @ 0x%x, 0x%x\n",
+ map_base, map_size);
}
#ifdef CONFIG_ACPI_SLEEP
@@ -167,6 +225,14 @@
if (!tboot_enabled())
return;
+ /*
+ * if we're being called before the 1:1 mapping is set up then just
+ * return and let the normal shutdown happen; this should only be
+ * due to very early panic()
+ */
+ if (!tboot_pg_dir)
+ return;
+
/* if this is S3 then set regions to MAC */
if (shutdown_type == TB_SHUTDOWN_S3)
if (tboot_setup_sleep())
@@ -277,6 +343,8 @@
if (!tboot_enabled())
return 0;
+ tboot_create_trampoline();
+
atomic_set(&ap_wfs_count, 0);
register_hotcpu_notifier(&tboot_cpu_notifier);