1 files changed, 127 insertions, 103 deletions

diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
index 6fac253bc783..49dbbae762ae 100644
--- a/arch/arm64/kernel/efi.c
+++ b/arch/arm64/kernel/efi.c
@@ -11,25 +11,31 @@
  *
  */
 
+#include <linux/atomic.h>
 #include <linux/dmi.h>
 #include <linux/efi.h>
 #include <linux/export.h>
 #include <linux/memblock.h>
+#include <linux/mm_types.h>
 #include <linux/bootmem.h>
 #include <linux/of.h>
 #include <linux/of_fdt.h>
+#include <linux/preempt.h>
+#include <linux/rbtree.h>
+#include <linux/rwsem.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
+#include <linux/spinlock.h>
 
 #include <asm/cacheflush.h>
 #include <asm/efi.h>
 #include <asm/tlbflush.h>
 #include <asm/mmu_context.h>
+#include <asm/mmu.h>
+#include <asm/pgtable.h>
 
 struct efi_memory_map memmap;
 
-static efi_runtime_services_t *runtime;
-
 static u64 efi_system_table;
 
 static int uefi_debug __initdata;
@@ -69,9 +75,33 @@ static void __init efi_setup_idmap(void)
 	}
 }
 
+/*
+ * Translate a EFI virtual address into a physical address: this is necessary,
+ * as some data members of the EFI system table are virtually remapped after
+ * SetVirtualAddressMap() has been called.
+ */
+static phys_addr_t efi_to_phys(unsigned long addr)
+{
+	efi_memory_desc_t *md;
+
+	for_each_efi_memory_desc(&memmap, md) {
+		if (!(md->attribute & EFI_MEMORY_RUNTIME))
+			continue;
+		if (md->virt_addr == 0)
+			/* no virtual mapping has been installed by the stub */
+			break;
+		if (md->virt_addr <= addr &&
+		    (addr - md->virt_addr) < (md->num_pages << EFI_PAGE_SHIFT))
+			return md->phys_addr + addr - md->virt_addr;
+	}
+	return addr;
+}
+
 static int __init uefi_init(void)
 {
 	efi_char16_t *c16;
+	void *config_tables;
+	u64 table_size;
 	char vendor[100] = "unknown";
 	int i, retval;
 
@@ -99,7 +129,7 @@ static int __init uefi_init(void)
 			efi.systab->hdr.revision & 0xffff);
 
 	/* Show what we know for posterity */
-	c16 = early_memremap(efi.systab->fw_vendor,
+	c16 = early_memremap(efi_to_phys(efi.systab->fw_vendor),
 			     sizeof(vendor));
 	if (c16) {
 		for (i = 0; i < (int) sizeof(vendor) - 1 && *c16; ++i)
@@ -112,8 +142,14 @@ static int __init uefi_init(void)
 		efi.systab->hdr.revision >> 16,
 		efi.systab->hdr.revision & 0xffff, vendor);
 
-	retval = efi_config_init(NULL);
+	table_size = sizeof(efi_config_table_64_t) * efi.systab->nr_tables;
+	config_tables = early_memremap(efi_to_phys(efi.systab->tables),
+				       table_size);
+
+	retval = efi_config_parse_tables(config_tables, efi.systab->nr_tables,
+					 sizeof(efi_config_table_64_t), NULL);
 
+	early_memunmap(config_tables, table_size);
 out:
 	early_memunmap(efi.systab,  sizeof(efi_system_table_t));
 	return retval;
@@ -328,51 +364,14 @@ void __init efi_idmap_init(void)
 	efi_setup_idmap();
 }
 
-static int __init remap_region(efi_memory_desc_t *md, void **new)
-{
-	u64 paddr, vaddr, npages, size;
-
-	paddr = md->phys_addr;
-	npages = md->num_pages;
-	memrange_efi_to_native(&paddr, &npages);
-	size = npages << PAGE_SHIFT;
-
-	if (is_normal_ram(md))
-		vaddr = (__force u64)ioremap_cache(paddr, size);
-	else
-		vaddr = (__force u64)ioremap(paddr, size);
-
-	if (!vaddr) {
-		pr_err("Unable to remap 0x%llx pages @ %p\n",
-		       npages, (void *)paddr);
-		return 0;
-	}
-
-	/* adjust for any rounding when EFI and system pagesize differs */
-	md->virt_addr = vaddr + (md->phys_addr - paddr);
-
-	if (uefi_debug)
-		pr_info("  EFI remap 0x%012llx => %p\n",
-			md->phys_addr, (void *)md->virt_addr);
-
-	memcpy(*new, md, memmap.desc_size);
-	*new += memmap.desc_size;
-
-	return 1;
-}
-
 /*
- * Switch UEFI from an identity map to a kernel virtual map
+ * Enable the UEFI Runtime Services if all prerequisites are in place, i.e.,
+ * non-early mapping of the UEFI system table and virtual mappings for all
+ * EFI_MEMORY_RUNTIME regions.
  */
-static int __init arm64_enter_virtual_mode(void)
+static int __init arm64_enable_runtime_services(void)
 {
-	efi_memory_desc_t *md;
-	phys_addr_t virtmap_phys;
-	void *virtmap, *virt_md;
-	efi_status_t status;
 	u64 mapsize;
-	int count = 0;
-	unsigned long flags;
 
 	if (!efi_enabled(EFI_BOOT)) {
 		pr_info("EFI services will not be available.\n");
@@ -395,81 +394,30 @@ static int __init arm64_enter_virtual_mode(void)
 
 	efi.memmap = &memmap;
 
-	/* Map the runtime regions */
-	virtmap = kmalloc(mapsize, GFP_KERNEL);
-	if (!virtmap) {
-		pr_err("Failed to allocate EFI virtual memmap\n");
-		return -1;
-	}
-	virtmap_phys = virt_to_phys(virtmap);
-	virt_md = virtmap;
-
-	for_each_efi_memory_desc(&memmap, md) {
-		if (!(md->attribute & EFI_MEMORY_RUNTIME))
-			continue;
-		if (!remap_region(md, &virt_md))
-			goto err_unmap;
-		++count;
-	}
-
-	efi.systab = (__force void *)efi_lookup_mapped_addr(efi_system_table);
+	efi.systab = (__force void *)ioremap_cache(efi_system_table,
+						   sizeof(efi_system_table_t));
 	if (!efi.systab) {
-		/*
-		 * If we have no virtual mapping for the System Table at this
-		 * point, the memory map doesn't cover the physical offset where
-		 * it resides. This means the System Table will be inaccessible
-		 * to Runtime Services themselves once the virtual mapping is
-		 * installed.
-		 */
-		pr_err("Failed to remap EFI System Table -- buggy firmware?\n");
-		goto err_unmap;
+		pr_err("Failed to remap EFI System Table\n");
+		return -1;
 	}
 	set_bit(EFI_SYSTEM_TABLES, &efi.flags);
 
-	local_irq_save(flags);
-	cpu_switch_mm(idmap_pg_dir, &init_mm);
-
-	/* Call SetVirtualAddressMap with the physical address of the map */
-	runtime = efi.systab->runtime;
-	efi.set_virtual_address_map = runtime->set_virtual_address_map;
-
-	status = efi.set_virtual_address_map(count * memmap.desc_size,
-					     memmap.desc_size,
-					     memmap.desc_version,
-					     (efi_memory_desc_t *)virtmap_phys);
-	cpu_set_reserved_ttbr0();
-	flush_tlb_all();
-	local_irq_restore(flags);
-
-	kfree(virtmap);
-
 	free_boot_services();
 
-	if (status != EFI_SUCCESS) {
-		pr_err("Failed to set EFI virtual address map! [%lx]\n",
-			status);
+	if (!efi_enabled(EFI_VIRTMAP)) {
+		pr_err("No UEFI virtual mapping was installed -- runtime services will not be available\n");
 		return -1;
 	}
 
 	/* Set up runtime services function pointers */
-	runtime = efi.systab->runtime;
 	efi_native_runtime_setup();
 	set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
 
 	efi.runtime_version = efi.systab->hdr.revision;
 
 	return 0;
-
-err_unmap:
-	/* unmap all mappings that succeeded: there are 'count' of those */
-	for (virt_md = virtmap; count--; virt_md += memmap.desc_size) {
-		md = virt_md;
-		iounmap((__force void __iomem *)md->virt_addr);
-	}
-	kfree(virtmap);
-	return -1;
 }
-early_initcall(arm64_enter_virtual_mode);
+early_initcall(arm64_enable_runtime_services);
 
 static int __init arm64_dmi_init(void)
 {
@@ -484,3 +432,79 @@ static int __init arm64_dmi_init(void)
 	return 0;
 }
 core_initcall(arm64_dmi_init);
+
+static pgd_t efi_pgd[PTRS_PER_PGD] __page_aligned_bss;
+
+static struct mm_struct efi_mm = {
+	.mm_rb			= RB_ROOT,
+	.pgd			= efi_pgd,
+	.mm_users		= ATOMIC_INIT(2),
+	.mm_count		= ATOMIC_INIT(1),
+	.mmap_sem		= __RWSEM_INITIALIZER(efi_mm.mmap_sem),
+	.page_table_lock	= __SPIN_LOCK_UNLOCKED(efi_mm.page_table_lock),
+	.mmlist			= LIST_HEAD_INIT(efi_mm.mmlist),
+	INIT_MM_CONTEXT(efi_mm)
+};
+
+static void efi_set_pgd(struct mm_struct *mm)
+{
+	cpu_switch_mm(mm->pgd, mm);
+	flush_tlb_all();
+	if (icache_is_aivivt())
+		__flush_icache_all();
+}
+
+void efi_virtmap_load(void)
+{
+	preempt_disable();
+	efi_set_pgd(&efi_mm);
+}
+
+void efi_virtmap_unload(void)
+{
+	efi_set_pgd(current->active_mm);
+	preempt_enable();
+}
+
+void __init efi_virtmap_init(void)
+{
+	efi_memory_desc_t *md;
+
+	if (!efi_enabled(EFI_BOOT))
+		return;
+
+	for_each_efi_memory_desc(&memmap, md) {
+		u64 paddr, npages, size;
+		pgprot_t prot;
+
+		if (!(md->attribute & EFI_MEMORY_RUNTIME))
+			continue;
+		if (WARN(md->virt_addr == 0,
+			 "UEFI virtual mapping incomplete or missing -- no entry found for 0x%llx\n",
+			 md->phys_addr))
+			return;
+
+		paddr = md->phys_addr;
+		npages = md->num_pages;
+		memrange_efi_to_native(&paddr, &npages);
+		size = npages << PAGE_SHIFT;
+
+		pr_info("  EFI remap 0x%016llx => %p\n",
+			md->phys_addr, (void *)md->virt_addr);
+
+		/*
+		 * Only regions of type EFI_RUNTIME_SERVICES_CODE need to be
+		 * executable, everything else can be mapped with the XN bits
+		 * set.
+		 */
+		if (!is_normal_ram(md))
+			prot = __pgprot(PROT_DEVICE_nGnRE);
+		else if (md->type == EFI_RUNTIME_SERVICES_CODE)
+			prot = PAGE_KERNEL_EXEC;
+		else
+			prot = PAGE_KERNEL;
+
+		create_pgd_mapping(&efi_mm, paddr, md->virt_addr, size, prot);
+	}
+	set_bit(EFI_VIRTMAP, &efi.flags);
+}