Commit message: efi/x86/Add missing error handling to old_memmap 1:1 mapping code

The old_memmap flow in efi_call_phys_prolog() performs numerous memory
allocations, and either does not check for failure at all, or it does
but fails to propagate it back to the caller, which may end up calling
into the firmware with an incomplete 1:1 mapping.

So let's fix this by returning NULL from efi_call_phys_prolog() on
memory allocation failures only, and by handling this condition in the
caller. Also, clean up any half baked sets of page tables that we may
have created before returning with a NULL return value.

Note that any failure at this level will trigger a panic() two levels
up, so none of this makes a huge difference, but it is a nice cleanup
nonetheless.

[ardb: update commit log, add efi_call_phys_epilog() call on error path]

Signed-off-by: Gen Zhang <blackgod016574@gmail.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rob Bradford <robert.bradford@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20190525112559.7917-2-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
CVE: CVE-2019-12380
CWE: CWE-388
Vulnerability description: **DISPUTED** An issue was discovered in the efi subsystem in the Linux kernel through 5.1.5. phys_efi_set_virtual_address_map in arch/x86/platform/efi/efi.c and efi_call_phys_prolog in arch/x86/platform/efi/efi_64.c mishandle memory allocation failures. NOTE: This id is disputed as not being an issue because “All the code touched by the referenced commit runs only at boot, before any user processes are started. Therefore, there is no possibility for an unprivileged user to control it.”.

Project: tip

static void __init kexec_enter_virtual_mode(void)
{
#ifdef CONFIG_KEXEC_CORE
	efi_memory_desc_t *md;
	unsigned int num_pages;

	efi.systab = NULL;

	/*
	 * We don't do virtual mode, since we don't do runtime services, on
	 * non-native EFI. With efi=old_map, we don't do runtime services in
	 * kexec kernel because in the initial boot something else might
	 * have been mapped at these virtual addresses.
	 */
	if (!efi_is_native() || efi_enabled(EFI_OLD_MEMMAP)) {
		efi_memmap_unmap();
		clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
		return;
	}

	if (efi_alloc_page_tables()) {
		pr_err("Failed to allocate EFI page tables\n");
		clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
		return;
	}

	/*
	* Map efi regions which were passed via setup_data. The virt_addr is a
	* fixed addr which was used in first kernel of a kexec boot.
	*/
	for_each_efi_memory_desc(md) {
		efi_map_region_fixed(md); /* FIXME: add error handling */
		get_systab_virt_addr(md);
	}

	/*
	 * Unregister the early EFI memmap from efi_init() and install
	 * the new EFI memory map.
	 */
	efi_memmap_unmap();

	if (efi_memmap_init_late(efi.memmap.phys_map,
				 efi.memmap.desc_size * efi.memmap.nr_map)) {
		pr_err("Failed to remap late EFI memory map\n");
		clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
		return;
	}

	BUG_ON(!efi.systab);

	num_pages = ALIGN(efi.memmap.nr_map * efi.memmap.desc_size, PAGE_SIZE);
	num_pages >>= PAGE_SHIFT;

	if (efi_setup_page_tables(efi.memmap.phys_map, num_pages)) {
		clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
		return;
	}

	efi_sync_low_kernel_mappings();

	/*
	 * Now that EFI is in virtual mode, update the function
	 * pointers in the runtime service table to the new virtual addresses.
	 *
	 * Call EFI services through wrapper functions.
	 */
	efi.runtime_version = efi_systab.hdr.revision;

	efi_native_runtime_setup();

	efi.set_virtual_address_map = NULL;

	if (efi_enabled(EFI_OLD_MEMMAP) && (__supported_pte_mask & _PAGE_NX))
		runtime_code_page_mkexec();

	/* clean DUMMY object */
	efi_delete_dummy_variable();
#endif
}

Project: tip

void __init parse_efi_setup(u64 phys_addr, u32 data_len)
{
	efi_setup = phys_addr + sizeof(struct setup_data);
}

Project: tip

efi_thunk_reset_system(int reset_type, efi_status_t status,
		       unsigned long data_size, efi_char16_t *data)
{
	u32 phys_data;
	unsigned long flags;

	spin_lock_irqsave(&efi_runtime_lock, flags);

	phys_data = virt_to_phys_or_null_size(data, data_size);

	efi_thunk(reset_system, reset_type, status, data_size, phys_data);

	spin_unlock_irqrestore(&efi_runtime_lock, flags);
}

Project: tip

static bool __init efi_memmap_entry_valid(const efi_memory_desc_t *md, int i)
{
	u64 end = (md->num_pages << EFI_PAGE_SHIFT) + md->phys_addr - 1;
	u64 end_hi = 0;
	char buf[64];

	if (md->num_pages == 0) {
		end = 0;
	} else if (md->num_pages > EFI_PAGES_MAX ||
		   EFI_PAGES_MAX - md->num_pages <
		   (md->phys_addr >> EFI_PAGE_SHIFT)) {
		end_hi = (md->num_pages & OVERFLOW_ADDR_MASK)
			>> OVERFLOW_ADDR_SHIFT;

		if ((md->phys_addr & U64_HIGH_BIT) && !(end & U64_HIGH_BIT))
			end_hi += 1;
	} else {
		return true;
	}

	pr_warn_once(FW_BUG "Invalid EFI memory map entries:\n");

	if (end_hi) {
		pr_warn("mem%02u: %s range=[0x%016llx-0x%llx%016llx] (invalid)\n",
			i, efi_md_typeattr_format(buf, sizeof(buf), md),
			md->phys_addr, end_hi, end);
	} else {
		pr_warn("mem%02u: %s range=[0x%016llx-0x%016llx] (invalid)\n",
			i, efi_md_typeattr_format(buf, sizeof(buf), md),
			md->phys_addr, end);
	}
	return false;
}

Project: tip

efi_thunk_get_wakeup_time(efi_bool_t *enabled, efi_bool_t *pending,
			  efi_time_t *tm)
{
	efi_status_t status;
	u32 phys_enabled, phys_pending, phys_tm;
	unsigned long flags;

	spin_lock(&rtc_lock);
	spin_lock_irqsave(&efi_runtime_lock, flags);

	phys_enabled = virt_to_phys_or_null(enabled);
	phys_pending = virt_to_phys_or_null(pending);
	phys_tm = virt_to_phys_or_null(tm);

	status = efi_thunk(get_wakeup_time, phys_enabled,
			     phys_pending, phys_tm);

	spin_unlock_irqrestore(&efi_runtime_lock, flags);
	spin_unlock(&rtc_lock);

	return status;
}

Project: tip

static void *realloc_pages(void *old_memmap, int old_shift)
{
	void *ret;

	ret = (void *)__get_free_pages(GFP_KERNEL, old_shift + 1);
	if (!ret)
		goto out;

	/*
	 * A first-time allocation doesn't have anything to copy.
	 */
	if (!old_memmap)
		return ret;

	memcpy(ret, old_memmap, PAGE_SIZE << old_shift);

out:
	free_pages((unsigned long)old_memmap, old_shift);
	return ret;
}

Project: tip

pgd_t * __init efi_call_phys_prolog(void)
{
	unsigned long vaddr, addr_pgd, addr_p4d, addr_pud;
	pgd_t *save_pgd, *pgd_k, *pgd_efi;
	p4d_t *p4d, *p4d_k, *p4d_efi;
	pud_t *pud;

	int pgd;
	int n_pgds, i, j;

	if (!efi_enabled(EFI_OLD_MEMMAP)) {
		efi_switch_mm(&efi_mm);
		return efi_mm.pgd;
	}

	early_code_mapping_set_exec(1);

	n_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT), PGDIR_SIZE);
	save_pgd = kmalloc_array(n_pgds, sizeof(*save_pgd), GFP_KERNEL);
	if (!save_pgd)
		return NULL;

	/*
	 * Build 1:1 identity mapping for efi=old_map usage. Note that
	 * PAGE_OFFSET is PGDIR_SIZE aligned when KASLR is disabled, while
	 * it is PUD_SIZE ALIGNED with KASLR enabled. So for a given physical
	 * address X, the pud_index(X) != pud_index(__va(X)), we can only copy
	 * PUD entry of __va(X) to fill in pud entry of X to build 1:1 mapping.
	 * This means here we can only reuse the PMD tables of the direct mapping.
	 */
	for (pgd = 0; pgd < n_pgds; pgd++) {
		addr_pgd = (unsigned long)(pgd * PGDIR_SIZE);
		vaddr = (unsigned long)__va(pgd * PGDIR_SIZE);
		pgd_efi = pgd_offset_k(addr_pgd);
		save_pgd[pgd] = *pgd_efi;

		p4d = p4d_alloc(&init_mm, pgd_efi, addr_pgd);
		if (!p4d) {
			pr_err("Failed to allocate p4d table!\n");
			goto out;
		}

		for (i = 0; i < PTRS_PER_P4D; i++) {
			addr_p4d = addr_pgd + i * P4D_SIZE;
			p4d_efi = p4d + p4d_index(addr_p4d);

			pud = pud_alloc(&init_mm, p4d_efi, addr_p4d);
			if (!pud) {
				pr_err("Failed to allocate pud table!\n");
				goto out;
			}

			for (j = 0; j < PTRS_PER_PUD; j++) {
				addr_pud = addr_p4d + j * PUD_SIZE;

				if (addr_pud > (max_pfn << PAGE_SHIFT))
					break;

				vaddr = (unsigned long)__va(addr_pud);

				pgd_k = pgd_offset_k(vaddr);
				p4d_k = p4d_offset(pgd_k, vaddr);
				pud[j] = *pud_offset(p4d_k, vaddr);
			}
		}
		pgd_offset_k(pgd * PGDIR_SIZE)->pgd &= ~_PAGE_NX;
	}

	__flush_tlb_all();
	return save_pgd;
out:
	efi_call_phys_epilog(save_pgd);
	return NULL;
}

Project: tip

virt_to_phys_or_null_size(void *va, unsigned long size)
{
	bool bad_size;

	if (!va)
		return 0;

	if (virt_addr_valid(va))
		return virt_to_phys(va);

	/*
	 * A fully aligned variable on the stack is guaranteed not to
	 * cross a page bounary. Try to catch strings on the stack by
	 * checking that 'size' is a power of two.
	 */
	bad_size = size > PAGE_SIZE || !is_power_of_2(size);

	WARN_ON(!IS_ALIGNED((unsigned long)va, size) || bad_size);

	return slow_virt_to_phys(va);
}

Project: tip

void __init efi_map_region(efi_memory_desc_t *md)
{
	unsigned long size = md->num_pages << PAGE_SHIFT;
	u64 pa = md->phys_addr;

	if (efi_enabled(EFI_OLD_MEMMAP))
		return old_map_region(md);

	/*
	 * Make sure the 1:1 mappings are present as a catch-all for b0rked
	 * firmware which doesn't update all internal pointers after switching
	 * to virtual mode and would otherwise crap on us.
	 */
	__map_region(md, md->phys_addr);

	/*
	 * Enforce the 1:1 mapping as the default virtual address when
	 * booting in EFI mixed mode, because even though we may be
	 * running a 64-bit kernel, the firmware may only be 32-bit.
	 */
	if (!efi_is_native () && IS_ENABLED(CONFIG_EFI_MIXED)) {
		md->virt_addr = md->phys_addr;
		return;
	}

	efi_va -= size;

	/* Is PA 2M-aligned? */
	if (!(pa & (PMD_SIZE - 1))) {
		efi_va &= PMD_MASK;
	} else {
		u64 pa_offset = pa & (PMD_SIZE - 1);
		u64 prev_va = efi_va;

		/* get us the same offset within this 2M page */
		efi_va = (efi_va & PMD_MASK) + pa_offset;

		if (efi_va > prev_va)
			efi_va -= PMD_SIZE;
	}

	if (efi_va < EFI_VA_END) {
		pr_warn(FW_WARN "VA address range overflow!\n");
		return;
	}

	/* Do the VA map */
	__map_region(md, efi_va);
	md->virt_addr = efi_va;
}

Project: tip

efi_thunk_query_capsule_caps(efi_capsule_header_t **capsules,
			     unsigned long count, u64 *max_size,
			     int *reset_type)
{
	/*
	 * To properly support this function we would need to repackage
	 * 'capsules' because the firmware doesn't understand 64-bit
	 * pointers.
	 */
	return EFI_UNSUPPORTED;
}

Project: tip

static int __init efi_update_mappings(efi_memory_desc_t *md, unsigned long pf)
{
	unsigned long pfn;
	pgd_t *pgd = efi_mm.pgd;
	int err1, err2;

	/* Update the 1:1 mapping */
	pfn = md->phys_addr >> PAGE_SHIFT;
	err1 = kernel_map_pages_in_pgd(pgd, pfn, md->phys_addr, md->num_pages, pf);
	if (err1) {
		pr_err("Error while updating 1:1 mapping PA 0x%llx -> VA 0x%llx!\n",
			   md->phys_addr, md->virt_addr);
	}

	err2 = kernel_map_pages_in_pgd(pgd, pfn, md->virt_addr, md->num_pages, pf);
	if (err2) {
		pr_err("Error while updating VA mapping PA 0x%llx -> VA 0x%llx!\n",
			   md->phys_addr, md->virt_addr);
	}

	return err1 || err2;
}

Project: tip

void __init efi_enter_virtual_mode(void)
{
	if (efi_enabled(EFI_PARAVIRT))
		return;

	if (efi_setup)
		kexec_enter_virtual_mode();
	else
		__efi_enter_virtual_mode();

	efi_dump_pagetable();
}

Project: tip

static efi_status_t efi_thunk_get_time(efi_time_t *tm, efi_time_cap_t *tc)
{
	efi_status_t status;
	u32 phys_tm, phys_tc;
	unsigned long flags;

	spin_lock(&rtc_lock);
	spin_lock_irqsave(&efi_runtime_lock, flags);

	phys_tm = virt_to_phys_or_null(tm);
	phys_tc = virt_to_phys_or_null(tc);

	status = efi_thunk(get_time, phys_tm, phys_tc);

	spin_unlock_irqrestore(&efi_runtime_lock, flags);
	spin_unlock(&rtc_lock);

	return status;
}

Project: tip

void efi_thunk_runtime_setup(void)
{
	efi.get_time = efi_thunk_get_time;
	efi.set_time = efi_thunk_set_time;
	efi.get_wakeup_time = efi_thunk_get_wakeup_time;
	efi.set_wakeup_time = efi_thunk_set_wakeup_time;
	efi.get_variable = efi_thunk_get_variable;
	efi.get_next_variable = efi_thunk_get_next_variable;
	efi.set_variable = efi_thunk_set_variable;
	efi.set_variable_nonblocking = efi_thunk_set_variable_nonblocking;
	efi.get_next_high_mono_count = efi_thunk_get_next_high_mono_count;
	efi.reset_system = efi_thunk_reset_system;
	efi.query_variable_info = efi_thunk_query_variable_info;
	efi.query_variable_info_nonblocking = efi_thunk_query_variable_info_nonblocking;
	efi.update_capsule = efi_thunk_update_capsule;
	efi.query_capsule_caps = efi_thunk_query_capsule_caps;
}

Project: tip

efi_status_t efi_thunk_set_virtual_address_map(
	void *phys_set_virtual_address_map,
	unsigned long memory_map_size,
	unsigned long descriptor_size,
	u32 descriptor_version,
	efi_memory_desc_t *virtual_map)
{
	efi_status_t status;
	unsigned long flags;
	u32 func;

	efi_sync_low_kernel_mappings();
	local_irq_save(flags);

	efi_switch_mm(&efi_mm);

	func = (u32)(unsigned long)phys_set_virtual_address_map;
	status = efi64_thunk(func, memory_map_size, descriptor_size,
			     descriptor_version, virtual_map);

	efi_switch_mm(efi_scratch.prev_mm);
	local_irq_restore(flags);

	return status;
}

Project: tip

static int __init efi_runtime_init(void)
{
	int rv;

	/*
	 * Check out the runtime services table. We need to map
	 * the runtime services table so that we can grab the physical
	 * address of several of the EFI runtime functions, needed to
	 * set the firmware into virtual mode.
	 *
	 * When EFI_PARAVIRT is in force then we could not map runtime
	 * service memory region because we do not have direct access to it.
	 * However, runtime services are available through proxy functions
	 * (e.g. in case of Xen dom0 EFI implementation they call special
	 * hypercall which executes relevant EFI functions) and that is why
	 * they are always enabled.
	 */

	if (!efi_enabled(EFI_PARAVIRT)) {
		if (efi_enabled(EFI_64BIT))
			rv = efi_runtime_init64();
		else
			rv = efi_runtime_init32();

		if (rv)
			return rv;
	}

	set_bit(EFI_RUNTIME_SERVICES, &efi.flags);

	return 0;
}

Project: tip

efi_thunk_set_variable(efi_char16_t *name, efi_guid_t *vendor,
		       u32 attr, unsigned long data_size, void *data)
{
	u32 phys_name, phys_vendor, phys_data;
	efi_status_t status;
	unsigned long flags;

	spin_lock_irqsave(&efi_runtime_lock, flags);

	phys_name = virt_to_phys_or_null_size(name, efi_name_size(name));
	phys_vendor = virt_to_phys_or_null(vendor);
	phys_data = virt_to_phys_or_null_size(data, data_size);

	/* If data_size is > sizeof(u32) we've got problems */
	status = efi_thunk(set_variable, phys_name, phys_vendor,
			   attr, data_size, phys_data);

	spin_unlock_irqrestore(&efi_runtime_lock, flags);

	return status;
}

Project: tip

void efi_switch_mm(struct mm_struct *mm)
{
	efi_scratch.prev_mm = current->active_mm;
	current->active_mm = mm;
	switch_mm(efi_scratch.prev_mm, mm, NULL);
}

Project: tip

static int __init setup_add_efi_memmap(char *arg)
{
	add_efi_memmap = 1;
	return 0;
}

Project: tip

void __iomem *__init efi_ioremap(unsigned long phys_addr, unsigned long size,
				 u32 type, u64 attribute)
{
	unsigned long last_map_pfn;

	if (type == EFI_MEMORY_MAPPED_IO)
		return ioremap(phys_addr, size);

	last_map_pfn = init_memory_mapping(phys_addr, phys_addr + size);
	if ((last_map_pfn << PAGE_SHIFT) < phys_addr + size) {
		unsigned long top = last_map_pfn << PAGE_SHIFT;
		efi_ioremap(top, size - (top - phys_addr), type, attribute);
	}

	if (!(attribute & EFI_MEMORY_WB))
		efi_memory_uc((u64)(unsigned long)__va(phys_addr), size);

	return (void __iomem *)__va(phys_addr);
}

Project: tip

void __init efi_init(void)
{
	efi_char16_t *c16;
	char vendor[100] = "unknown";
	int i = 0;
	void *tmp;

#ifdef CONFIG_X86_32
	if (boot_params.efi_info.efi_systab_hi ||
	    boot_params.efi_info.efi_memmap_hi) {
		pr_info("Table located above 4GB, disabling EFI.\n");
		return;
	}
	efi_phys.systab = (efi_system_table_t *)boot_params.efi_info.efi_systab;
#else
	efi_phys.systab = (efi_system_table_t *)
			  (boot_params.efi_info.efi_systab |
			  ((__u64)boot_params.efi_info.efi_systab_hi<<32));
#endif

	if (efi_systab_init(efi_phys.systab))
		return;

	efi.config_table = (unsigned long)efi.systab->tables;
	efi.fw_vendor	 = (unsigned long)efi.systab->fw_vendor;
	efi.runtime	 = (unsigned long)efi.systab->runtime;

	/*
	 * Show what we know for posterity
	 */
	c16 = tmp = early_memremap(efi.systab->fw_vendor, 2);
	if (c16) {
		for (i = 0; i < sizeof(vendor) - 1 && *c16; ++i)
			vendor[i] = *c16++;
		vendor[i] = '\0';
	} else
		pr_err("Could not map the firmware vendor!\n");
	early_memunmap(tmp, 2);

	pr_info("EFI v%u.%.02u by %s\n",
		efi.systab->hdr.revision >> 16,
		efi.systab->hdr.revision & 0xffff, vendor);

	if (efi_reuse_config(efi.systab->tables, efi.systab->nr_tables))
		return;

	if (efi_config_init(arch_tables))
		return;

	/*
	 * Note: We currently don't support runtime services on an EFI
	 * that doesn't match the kernel 32/64-bit mode.
	 */

	if (!efi_runtime_supported())
		pr_info("No EFI runtime due to 32/64-bit mismatch with kernel\n");
	else {
		if (efi_runtime_disabled() || efi_runtime_init()) {
			efi_memmap_unmap();
			return;
		}
	}

	efi_clean_memmap();

	if (efi_enabled(EFI_DBG))
		efi_print_memmap();
}

Project: tip

int __init efi_alloc_page_tables(void)
{
	pgd_t *pgd, *efi_pgd;
	p4d_t *p4d;
	pud_t *pud;
	gfp_t gfp_mask;

	if (efi_enabled(EFI_OLD_MEMMAP))
		return 0;

	gfp_mask = GFP_KERNEL | __GFP_ZERO;
	efi_pgd = (pgd_t *)__get_free_pages(gfp_mask, PGD_ALLOCATION_ORDER);
	if (!efi_pgd)
		return -ENOMEM;

	pgd = efi_pgd + pgd_index(EFI_VA_END);
	p4d = p4d_alloc(&init_mm, pgd, EFI_VA_END);
	if (!p4d) {
		free_page((unsigned long)efi_pgd);
		return -ENOMEM;
	}

	pud = pud_alloc(&init_mm, p4d, EFI_VA_END);
	if (!pud) {
		if (pgtable_l5_enabled())
			free_page((unsigned long) pgd_page_vaddr(*pgd));
		free_pages((unsigned long)efi_pgd, PGD_ALLOCATION_ORDER);
		return -ENOMEM;
	}

	efi_mm.pgd = efi_pgd;
	mm_init_cpumask(&efi_mm);
	init_new_context(NULL, &efi_mm);

	return 0;
}

Project: tip

static efi_status_t efi_thunk_set_time(efi_time_t *tm)
{
	efi_status_t status;
	u32 phys_tm;
	unsigned long flags;

	spin_lock(&rtc_lock);
	spin_lock_irqsave(&efi_runtime_lock, flags);

	phys_tm = virt_to_phys_or_null(tm);

	status = efi_thunk(set_time, phys_tm);

	spin_unlock_irqrestore(&efi_runtime_lock, flags);
	spin_unlock(&rtc_lock);

	return status;
}

Project: tip

efi_thunk_update_capsule(efi_capsule_header_t **capsules,
			 unsigned long count, unsigned long sg_list)
{
	/*
	 * To properly support this function we would need to repackage
	 * 'capsules' because the firmware doesn't understand 64-bit
	 * pointers.
	 */
	return EFI_UNSUPPORTED;
}

Project: tip

static int __init efi_update_mem_attr(struct mm_struct *mm, efi_memory_desc_t *md)
{
	unsigned long pf = 0;

	if (md->attribute & EFI_MEMORY_XP)
		pf |= _PAGE_NX;

	if (!(md->attribute & EFI_MEMORY_RO))
		pf |= _PAGE_RW;

	if (sev_active())
		pf |= _PAGE_ENC;

	return efi_update_mappings(md, pf);
}

Project: tip

static int __init efi_systab_init(void *phys)
{
	if (efi_enabled(EFI_64BIT)) {
		efi_system_table_64_t *systab64;
		struct efi_setup_data *data = NULL;
		u64 tmp = 0;

		if (efi_setup) {
			data = early_memremap(efi_setup, sizeof(*data));
			if (!data)
				return -ENOMEM;
		}
		systab64 = early_memremap((unsigned long)phys,
					 sizeof(*systab64));
		if (systab64 == NULL) {
			pr_err("Couldn't map the system table!\n");
			if (data)
				early_memunmap(data, sizeof(*data));
			return -ENOMEM;
		}

		efi_systab.hdr = systab64->hdr;
		efi_systab.fw_vendor = data ? (unsigned long)data->fw_vendor :
					      systab64->fw_vendor;
		tmp |= data ? data->fw_vendor : systab64->fw_vendor;
		efi_systab.fw_revision = systab64->fw_revision;
		efi_systab.con_in_handle = systab64->con_in_handle;
		tmp |= systab64->con_in_handle;
		efi_systab.con_in = systab64->con_in;
		tmp |= systab64->con_in;
		efi_systab.con_out_handle = systab64->con_out_handle;
		tmp |= systab64->con_out_handle;
		efi_systab.con_out = systab64->con_out;
		tmp |= systab64->con_out;
		efi_systab.stderr_handle = systab64->stderr_handle;
		tmp |= systab64->stderr_handle;
		efi_systab.stderr = systab64->stderr;
		tmp |= systab64->stderr;
		efi_systab.runtime = data ?
				     (void *)(unsigned long)data->runtime :
				     (void *)(unsigned long)systab64->runtime;
		tmp |= data ? data->runtime : systab64->runtime;
		efi_systab.boottime = (void *)(unsigned long)systab64->boottime;
		tmp |= systab64->boottime;
		efi_systab.nr_tables = systab64->nr_tables;
		efi_systab.tables = data ? (unsigned long)data->tables :
					   systab64->tables;
		tmp |= data ? data->tables : systab64->tables;

		early_memunmap(systab64, sizeof(*systab64));
		if (data)
			early_memunmap(data, sizeof(*data));
#ifdef CONFIG_X86_32
		if (tmp >> 32) {
			pr_err("EFI data located above 4GB, disabling EFI.\n");
			return -EINVAL;
		}
#endif
	} else {
		efi_system_table_32_t *systab32;

		systab32 = early_memremap((unsigned long)phys,
					 sizeof(*systab32));
		if (systab32 == NULL) {
			pr_err("Couldn't map the system table!\n");
			return -ENOMEM;
		}

		efi_systab.hdr = systab32->hdr;
		efi_systab.fw_vendor = systab32->fw_vendor;
		efi_systab.fw_revision = systab32->fw_revision;
		efi_systab.con_in_handle = systab32->con_in_handle;
		efi_systab.con_in = systab32->con_in;
		efi_systab.con_out_handle = systab32->con_out_handle;
		efi_systab.con_out = systab32->con_out;
		efi_systab.stderr_handle = systab32->stderr_handle;
		efi_systab.stderr = systab32->stderr;
		efi_systab.runtime = (void *)(unsigned long)systab32->runtime;
		efi_systab.boottime = (void *)(unsigned long)systab32->boottime;
		efi_systab.nr_tables = systab32->nr_tables;
		efi_systab.tables = systab32->tables;

		early_memunmap(systab32, sizeof(*systab32));
	}

	efi.systab = &efi_systab;

	/*
	 * Verify the EFI Table
	 */
	if (efi.systab->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE) {
		pr_err("System table signature incorrect!\n");
		return -EINVAL;
	}
	if ((efi.systab->hdr.revision >> 16) == 0)
		pr_err("Warning: System table version %d.%02d, expected 1.00 or greater!\n",
		       efi.systab->hdr.revision >> 16,
		       efi.systab->hdr.revision & 0xffff);

	return 0;
}

Project: tip

void __init runtime_code_page_mkexec(void)
{
	efi_memory_desc_t *md;

	/* Make EFI runtime service code area executable */
	for_each_efi_memory_desc(md) {
		if (md->type != EFI_RUNTIME_SERVICES_CODE)
			continue;

		efi_set_executable(md, true);
	}
}

Project: tip

void __init efi_memory_uc(u64 addr, unsigned long size)
{
	unsigned long page_shift = 1UL << EFI_PAGE_SHIFT;
	u64 npages;

	npages = round_up(size, page_shift) / page_shift;
	memrange_efi_to_native(&addr, &npages);
	set_memory_uc(addr, npages);
}

Project: tip

efi_thunk_get_variable(efi_char16_t *name, efi_guid_t *vendor,
		       u32 *attr, unsigned long *data_size, void *data)
{
	efi_status_t status;
	u32 phys_name, phys_vendor, phys_attr;
	u32 phys_data_size, phys_data;
	unsigned long flags;

	spin_lock_irqsave(&efi_runtime_lock, flags);

	phys_data_size = virt_to_phys_or_null(data_size);
	phys_vendor = virt_to_phys_or_null(vendor);
	phys_name = virt_to_phys_or_null_size(name, efi_name_size(name));
	phys_attr = virt_to_phys_or_null(attr);
	phys_data = virt_to_phys_or_null_size(data, *data_size);

	status = efi_thunk(get_variable, phys_name, phys_vendor,
			   phys_attr, phys_data_size, phys_data);

	spin_unlock_irqrestore(&efi_runtime_lock, flags);

	return status;
}

Project: tip

void __init efi_call_phys_epilog(pgd_t *save_pgd)
{
	/*
	 * After the lock is released, the original page table is restored.
	 */
	int pgd_idx, i;
	int nr_pgds;
	pgd_t *pgd;
	p4d_t *p4d;
	pud_t *pud;

	if (!efi_enabled(EFI_OLD_MEMMAP)) {
		efi_switch_mm(efi_scratch.prev_mm);
		return;
	}

	nr_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT) , PGDIR_SIZE);

	for (pgd_idx = 0; pgd_idx < nr_pgds; pgd_idx++) {
		pgd = pgd_offset_k(pgd_idx * PGDIR_SIZE);
		set_pgd(pgd_offset_k(pgd_idx * PGDIR_SIZE), save_pgd[pgd_idx]);

		if (!pgd_present(*pgd))
			continue;

		for (i = 0; i < PTRS_PER_P4D; i++) {
			p4d = p4d_offset(pgd,
					 pgd_idx * PGDIR_SIZE + i * P4D_SIZE);

			if (!p4d_present(*p4d))
				continue;

			pud = (pud_t *)p4d_page_vaddr(*p4d);
			pud_free(&init_mm, pud);
		}

		p4d = (p4d_t *)pgd_page_vaddr(*pgd);
		p4d_free(&init_mm, p4d);
	}

	kfree(save_pgd);

	__flush_tlb_all();
	early_code_mapping_set_exec(0);
}

Project: tip

efi_thunk_get_next_high_mono_count(u32 *count)
{
	efi_status_t status;
	u32 phys_count;
	unsigned long flags;

	spin_lock_irqsave(&efi_runtime_lock, flags);

	phys_count = virt_to_phys_or_null(count);
	status = efi_thunk(get_next_high_mono_count, phys_count);

	spin_unlock_irqrestore(&efi_runtime_lock, flags);

	return status;
}

Project: tip

static void __init get_systab_virt_addr(efi_memory_desc_t *md)
{
	unsigned long size;
	u64 end, systab;

	size = md->num_pages << EFI_PAGE_SHIFT;
	end = md->phys_addr + size;
	systab = (u64)(unsigned long)efi_phys.systab;
	if (md->phys_addr <= systab && systab < end) {
		systab += md->virt_addr - md->phys_addr;
		efi.systab = (efi_system_table_t *)(unsigned long)systab;
	}
}

Project: tip

efi_thunk_get_next_variable(unsigned long *name_size,
			    efi_char16_t *name,
			    efi_guid_t *vendor)
{
	efi_status_t status;
	u32 phys_name_size, phys_name, phys_vendor;
	unsigned long flags;

	spin_lock_irqsave(&efi_runtime_lock, flags);

	phys_name_size = virt_to_phys_or_null(name_size);
	phys_vendor = virt_to_phys_or_null(vendor);
	phys_name = virt_to_phys_or_null_size(name, *name_size);

	status = efi_thunk(get_next_variable, phys_name_size,
			   phys_name, phys_vendor);

	spin_unlock_irqrestore(&efi_runtime_lock, flags);

	return status;
}

Project: tip

static inline void *efi_map_next_entry_reverse(void *entry)
{
	/* Initial call */
	if (!entry)
		return efi.memmap.map_end - efi.memmap.desc_size;

	entry -= efi.memmap.desc_size;
	if (entry < efi.memmap.map)
		return NULL;

	return entry;
}

Project: tip

void efi_sync_low_kernel_mappings(void)
{
	unsigned num_entries;
	pgd_t *pgd_k, *pgd_efi;
	p4d_t *p4d_k, *p4d_efi;
	pud_t *pud_k, *pud_efi;
	pgd_t *efi_pgd = efi_mm.pgd;

	if (efi_enabled(EFI_OLD_MEMMAP))
		return;

	/*
	 * We can share all PGD entries apart from the one entry that
	 * covers the EFI runtime mapping space.
	 *
	 * Make sure the EFI runtime region mappings are guaranteed to
	 * only span a single PGD entry and that the entry also maps
	 * other important kernel regions.
	 */
	MAYBE_BUILD_BUG_ON(pgd_index(EFI_VA_END) != pgd_index(MODULES_END));
	MAYBE_BUILD_BUG_ON((EFI_VA_START & PGDIR_MASK) !=
			(EFI_VA_END & PGDIR_MASK));

	pgd_efi = efi_pgd + pgd_index(PAGE_OFFSET);
	pgd_k = pgd_offset_k(PAGE_OFFSET);

	num_entries = pgd_index(EFI_VA_END) - pgd_index(PAGE_OFFSET);
	memcpy(pgd_efi, pgd_k, sizeof(pgd_t) * num_entries);

	/*
	 * As with PGDs, we share all P4D entries apart from the one entry
	 * that covers the EFI runtime mapping space.
	 */
	BUILD_BUG_ON(p4d_index(EFI_VA_END) != p4d_index(MODULES_END));
	BUILD_BUG_ON((EFI_VA_START & P4D_MASK) != (EFI_VA_END & P4D_MASK));

	pgd_efi = efi_pgd + pgd_index(EFI_VA_END);
	pgd_k = pgd_offset_k(EFI_VA_END);
	p4d_efi = p4d_offset(pgd_efi, 0);
	p4d_k = p4d_offset(pgd_k, 0);

	num_entries = p4d_index(EFI_VA_END);
	memcpy(p4d_efi, p4d_k, sizeof(p4d_t) * num_entries);

	/*
	 * We share all the PUD entries apart from those that map the
	 * EFI regions. Copy around them.
	 */
	BUILD_BUG_ON((EFI_VA_START & ~PUD_MASK) != 0);
	BUILD_BUG_ON((EFI_VA_END & ~PUD_MASK) != 0);

	p4d_efi = p4d_offset(pgd_efi, EFI_VA_END);
	p4d_k = p4d_offset(pgd_k, EFI_VA_END);
	pud_efi = pud_offset(p4d_efi, 0);
	pud_k = pud_offset(p4d_k, 0);

	num_entries = pud_index(EFI_VA_END);
	memcpy(pud_efi, pud_k, sizeof(pud_t) * num_entries);

	pud_efi = pud_offset(p4d_efi, EFI_VA_START);
	pud_k = pud_offset(p4d_k, EFI_VA_START);

	num_entries = PTRS_PER_PUD - pud_index(EFI_VA_START);
	memcpy(pud_efi, pud_k, sizeof(pud_t) * num_entries);
}

Project: tip

efi_thunk_query_variable_info(u32 attr, u64 *storage_space,
			      u64 *remaining_space,
			      u64 *max_variable_size)
{
	efi_status_t status;
	u32 phys_storage, phys_remaining, phys_max;
	unsigned long flags;

	if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
		return EFI_UNSUPPORTED;

	spin_lock_irqsave(&efi_runtime_lock, flags);

	phys_storage = virt_to_phys_or_null(storage_space);
	phys_remaining = virt_to_phys_or_null(remaining_space);
	phys_max = virt_to_phys_or_null(max_variable_size);

	status = efi_thunk(query_variable_info, attr, phys_storage,
			   phys_remaining, phys_max);

	spin_unlock_irqrestore(&efi_runtime_lock, flags);

	return status;
}

Project: tip

void __init efi_set_executable(efi_memory_desc_t *md, bool executable)
{
	u64 addr, npages;

	addr = md->virt_addr;
	npages = md->num_pages;

	memrange_efi_to_native(&addr, &npages);

	if (executable)
		set_memory_x(addr, npages);
	else
		set_memory_nx(addr, npages);
}

Project: tip

static void __init efi_clean_memmap(void)
{
	efi_memory_desc_t *out = efi.memmap.map;
	const efi_memory_desc_t *in = out;
	const efi_memory_desc_t *end = efi.memmap.map_end;
	int i, n_removal;

	for (i = n_removal = 0; in < end; i++) {
		if (efi_memmap_entry_valid(in, i)) {
			if (out != in)
				memcpy(out, in, efi.memmap.desc_size);
			out = (void *)out + efi.memmap.desc_size;
		} else {
			n_removal++;
		}
		in = (void *)in + efi.memmap.desc_size;
	}

	if (n_removal > 0) {
		u64 size = efi.memmap.nr_map - n_removal;

		pr_warn("Removing %d invalid memory map entries.\n", n_removal);
		efi_memmap_install(efi.memmap.phys_map, size);
	}
}

Project: tip

efi_thunk_set_wakeup_time(efi_bool_t enabled, efi_time_t *tm)
{
	efi_status_t status;
	u32 phys_tm;
	unsigned long flags;

	spin_lock(&rtc_lock);
	spin_lock_irqsave(&efi_runtime_lock, flags);

	phys_tm = virt_to_phys_or_null(tm);

	status = efi_thunk(set_wakeup_time, enabled, phys_tm);

	spin_unlock_irqrestore(&efi_runtime_lock, flags);
	spin_unlock(&rtc_lock);

	return status;
}

Project: tip

static int __init efi_runtime_init32(void)
{
	efi_runtime_services_32_t *runtime;

	runtime = early_memremap((unsigned long)efi.systab->runtime,
			sizeof(efi_runtime_services_32_t));
	if (!runtime) {
		pr_err("Could not map the runtime service table!\n");
		return -ENOMEM;
	}

	/*
	 * We will only need *early* access to the SetVirtualAddressMap
	 * EFI runtime service. All other runtime services will be called
	 * via the virtual mapping.
	 */
	efi_phys.set_virtual_address_map =
			(efi_set_virtual_address_map_t *)
			(unsigned long)runtime->set_virtual_address_map;
	early_memunmap(runtime, sizeof(efi_runtime_services_32_t));

	return 0;
}

Project: tip

void __init efi_find_mirror(void)
{
	efi_memory_desc_t *md;
	u64 mirror_size = 0, total_size = 0;

	for_each_efi_memory_desc(md) {
		unsigned long long start = md->phys_addr;
		unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;

		total_size += size;
		if (md->attribute & EFI_MEMORY_MORE_RELIABLE) {
			memblock_mark_mirror(start, size);
			mirror_size += size;
		}
	}
	if (mirror_size)
		pr_info("Memory: %lldM/%lldM mirrored memory\n",
			mirror_size>>20, total_size>>20);
}

Project: tip

void __init efi_print_memmap(void)
{
	efi_memory_desc_t *md;
	int i = 0;

	for_each_efi_memory_desc(md) {
		char buf[64];

		pr_info("mem%02u: %s range=[0x%016llx-0x%016llx] (%lluMB)\n",
			i++, efi_md_typeattr_format(buf, sizeof(buf), md),
			md->phys_addr,
			md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT) - 1,
			(md->num_pages >> (20 - EFI_PAGE_SHIFT)));
	}
}

Project: tip

static bool should_map_region(efi_memory_desc_t *md)
{
	/*
	 * Runtime regions always require runtime mappings (obviously).
	 */
	if (md->attribute & EFI_MEMORY_RUNTIME)
		return true;

	/*
	 * 32-bit EFI doesn't suffer from the bug that requires us to
	 * reserve boot services regions, and mixed mode support
	 * doesn't exist for 32-bit kernels.
	 */
	if (IS_ENABLED(CONFIG_X86_32))
		return false;

	/*
	 * Map all of RAM so that we can access arguments in the 1:1
	 * mapping when making EFI runtime calls.
	 */
	if (IS_ENABLED(CONFIG_EFI_MIXED) && !efi_is_native()) {
		if (md->type == EFI_CONVENTIONAL_MEMORY ||
		    md->type == EFI_LOADER_DATA ||
		    md->type == EFI_LOADER_CODE)
			return true;
	}

	/*
	 * Map boot services regions as a workaround for buggy
	 * firmware that accesses them even when they shouldn't.
	 *
	 * See efi_{reserve,free}_boot_services().
	 */
	if (md->type == EFI_BOOT_SERVICES_CODE ||
	    md->type == EFI_BOOT_SERVICES_DATA)
		return true;

	return false;
}

Project: tip

static efi_status_t __init phys_efi_set_virtual_address_map(
	unsigned long memory_map_size,
	unsigned long descriptor_size,
	u32 descriptor_version,
	efi_memory_desc_t *virtual_map)
{
	efi_status_t status;
	unsigned long flags;
	pgd_t *save_pgd;

	save_pgd = efi_call_phys_prolog();
	if (!save_pgd)
		return EFI_ABORTED;

	/* Disable interrupts around EFI calls: */
	local_irq_save(flags);
	status = efi_call_phys(efi_phys.set_virtual_address_map,
			       memory_map_size, descriptor_size,
			       descriptor_version, virtual_map);
	local_irq_restore(flags);

	efi_call_phys_epilog(save_pgd);

	return status;
}

Project: tip

void __init efi_dump_pagetable(void)
{
#ifdef CONFIG_EFI_PGT_DUMP
	if (efi_enabled(EFI_OLD_MEMMAP))
		ptdump_walk_pgd_level(NULL, swapper_pg_dir);
	else
		ptdump_walk_pgd_level(NULL, efi_mm.pgd);
#endif
}

Project: tip

static void __init __map_region(efi_memory_desc_t *md, u64 va)
{
	unsigned long flags = _PAGE_RW;
	unsigned long pfn;
	pgd_t *pgd = efi_mm.pgd;

	if (!(md->attribute & EFI_MEMORY_WB))
		flags |= _PAGE_PCD;

	if (sev_active() && md->type != EFI_MEMORY_MAPPED_IO)
		flags |= _PAGE_ENC;

	pfn = md->phys_addr >> PAGE_SHIFT;
	if (kernel_map_pages_in_pgd(pgd, pfn, va, md->num_pages, flags))
		pr_warn("Error mapping PA 0x%llx -> VA 0x%llx!\n",
			   md->phys_addr, va);
}

Project: tip

efi_thunk_set_variable_nonblocking(efi_char16_t *name, efi_guid_t *vendor,
				   u32 attr, unsigned long data_size,
				   void *data)
{
	u32 phys_name, phys_vendor, phys_data;
	efi_status_t status;
	unsigned long flags;

	if (!spin_trylock_irqsave(&efi_runtime_lock, flags))
		return EFI_NOT_READY;

	phys_name = virt_to_phys_or_null_size(name, efi_name_size(name));
	phys_vendor = virt_to_phys_or_null(vendor);
	phys_data = virt_to_phys_or_null_size(data, data_size);

	/* If data_size is > sizeof(u32) we've got problems */
	status = efi_thunk(set_variable, phys_name, phys_vendor,
			   attr, data_size, phys_data);

	spin_unlock_irqrestore(&efi_runtime_lock, flags);

	return status;
}

Project: tip

static void __init __efi_enter_virtual_mode(void)
{
	int count = 0, pg_shift = 0;
	void *new_memmap = NULL;
	efi_status_t status;
	unsigned long pa;

	efi.systab = NULL;

	if (efi_alloc_page_tables()) {
		pr_err("Failed to allocate EFI page tables\n");
		clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
		return;
	}

	efi_merge_regions();
	new_memmap = efi_map_regions(&count, &pg_shift);
	if (!new_memmap) {
		pr_err("Error reallocating memory, EFI runtime non-functional!\n");
		clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
		return;
	}

	pa = __pa(new_memmap);

	/*
	 * Unregister the early EFI memmap from efi_init() and install
	 * the new EFI memory map that we are about to pass to the
	 * firmware via SetVirtualAddressMap().
	 */
	efi_memmap_unmap();

	if (efi_memmap_init_late(pa, efi.memmap.desc_size * count)) {
		pr_err("Failed to remap late EFI memory map\n");
		clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
		return;
	}

	if (efi_enabled(EFI_DBG)) {
		pr_info("EFI runtime memory map:\n");
		efi_print_memmap();
	}

	BUG_ON(!efi.systab);

	if (efi_setup_page_tables(pa, 1 << pg_shift)) {
		clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
		return;
	}

	efi_sync_low_kernel_mappings();

	if (efi_is_native()) {
		status = phys_efi_set_virtual_address_map(
				efi.memmap.desc_size * count,
				efi.memmap.desc_size,
				efi.memmap.desc_version,
				(efi_memory_desc_t *)pa);
	} else {
		status = efi_thunk_set_virtual_address_map(
				efi_phys.set_virtual_address_map,
				efi.memmap.desc_size * count,
				efi.memmap.desc_size,
				efi.memmap.desc_version,
				(efi_memory_desc_t *)pa);
	}

	if (status != EFI_SUCCESS) {
		pr_alert("Unable to switch EFI into virtual mode (status=%lx)!\n",
			 status);
		panic("EFI call to SetVirtualAddressMap() failed!");
	}

	efi_free_boot_services();

	/*
	 * Now that EFI is in virtual mode, update the function
	 * pointers in the runtime service table to the new virtual addresses.
	 *
	 * Call EFI services through wrapper functions.
	 */
	efi.runtime_version = efi_systab.hdr.revision;

	if (efi_is_native())
		efi_native_runtime_setup();
	else
		efi_thunk_runtime_setup();

	efi.set_virtual_address_map = NULL;

	/*
	 * Apply more restrictive page table mapping attributes now that
	 * SVAM() has been called and the firmware has performed all
	 * necessary relocation fixups for the new virtual addresses.
	 */
	efi_runtime_update_mappings();

	/* clean DUMMY object */
	efi_delete_dummy_variable();
}

Project: tip

static void __init early_code_mapping_set_exec(int executable)
{
	efi_memory_desc_t *md;

	if (!(__supported_pte_mask & _PAGE_NX))
		return;

	/* Make EFI service code area executable */
	for_each_efi_memory_desc(md) {
		if (md->type == EFI_RUNTIME_SERVICES_CODE ||
		    md->type == EFI_BOOT_SERVICES_CODE)
			efi_set_executable(md, executable);
	}
}

Project: tip

static int __init efi_runtime_init64(void)
{
	efi_runtime_services_64_t *runtime;

	runtime = early_memremap((unsigned long)efi.systab->runtime,
			sizeof(efi_runtime_services_64_t));
	if (!runtime) {
		pr_err("Could not map the runtime service table!\n");
		return -ENOMEM;
	}

	/*
	 * We will only need *early* access to the SetVirtualAddressMap
	 * EFI runtime service. All other runtime services will be called
	 * via the virtual mapping.
	 */
	efi_phys.set_virtual_address_map =
			(efi_set_virtual_address_map_t *)
			(unsigned long)runtime->set_virtual_address_map;
	early_memunmap(runtime, sizeof(efi_runtime_services_64_t));

	return 0;
}

Project: tip

void __init efi_map_region_fixed(efi_memory_desc_t *md)
{
	__map_region(md, md->phys_addr);
	__map_region(md, md->virt_addr);
}

Project: tip

static void * __init efi_map_regions(int *count, int *pg_shift)
{
	void *p, *new_memmap = NULL;
	unsigned long left = 0;
	unsigned long desc_size;
	efi_memory_desc_t *md;

	desc_size = efi.memmap.desc_size;

	p = NULL;
	while ((p = efi_map_next_entry(p))) {
		md = p;

		if (!should_map_region(md))
			continue;

		efi_map_region(md);
		get_systab_virt_addr(md);

		if (left < desc_size) {
			new_memmap = realloc_pages(new_memmap, *pg_shift);
			if (!new_memmap)
				return NULL;

			left += PAGE_SIZE << *pg_shift;
			(*pg_shift)++;
		}

		memcpy(new_memmap + (*count * desc_size), md, desc_size);

		left -= desc_size;
		(*count)++;
	}

	return new_memmap;
}

Project: tip

void __init efi_runtime_update_mappings(void)
{
	efi_memory_desc_t *md;

	if (efi_enabled(EFI_OLD_MEMMAP)) {
		if (__supported_pte_mask & _PAGE_NX)
			runtime_code_page_mkexec();
		return;
	}

	/*
	 * Use the EFI Memory Attribute Table for mapping permissions if it
	 * exists, since it is intended to supersede EFI_PROPERTIES_TABLE.
	 */
	if (efi_enabled(EFI_MEM_ATTR)) {
		efi_memattr_apply_permissions(NULL, efi_update_mem_attr);
		return;
	}

	/*
	 * EFI_MEMORY_ATTRIBUTES_TABLE is intended to replace
	 * EFI_PROPERTIES_TABLE. So, use EFI_PROPERTIES_TABLE to update
	 * permissions only if EFI_MEMORY_ATTRIBUTES_TABLE is not
	 * published by the firmware. Even if we find a buggy implementation of
	 * EFI_MEMORY_ATTRIBUTES_TABLE, don't fall back to
	 * EFI_PROPERTIES_TABLE, because of the same reason.
	 */

	if (!efi_enabled(EFI_NX_PE_DATA))
		return;

	for_each_efi_memory_desc(md) {
		unsigned long pf = 0;

		if (!(md->attribute & EFI_MEMORY_RUNTIME))
			continue;

		if (!(md->attribute & EFI_MEMORY_WB))
			pf |= _PAGE_PCD;

		if ((md->attribute & EFI_MEMORY_XP) ||
			(md->type == EFI_RUNTIME_SERVICES_DATA))
			pf |= _PAGE_NX;

		if (!(md->attribute & EFI_MEMORY_RO) &&
			(md->type != EFI_RUNTIME_SERVICES_CODE))
			pf |= _PAGE_RW;

		if (sev_active())
			pf |= _PAGE_ENC;

		efi_update_mappings(md, pf);
	}
}

Project: tip

static void __init do_add_efi_memmap(void)
{
	efi_memory_desc_t *md;

	for_each_efi_memory_desc(md) {
		unsigned long long start = md->phys_addr;
		unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
		int e820_type;

		switch (md->type) {
		case EFI_LOADER_CODE:
		case EFI_LOADER_DATA:
		case EFI_BOOT_SERVICES_CODE:
		case EFI_BOOT_SERVICES_DATA:
		case EFI_CONVENTIONAL_MEMORY:
			if (md->attribute & EFI_MEMORY_WB)
				e820_type = E820_TYPE_RAM;
			else
				e820_type = E820_TYPE_RESERVED;
			break;
		case EFI_ACPI_RECLAIM_MEMORY:
			e820_type = E820_TYPE_ACPI;
			break;
		case EFI_ACPI_MEMORY_NVS:
			e820_type = E820_TYPE_NVS;
			break;
		case EFI_UNUSABLE_MEMORY:
			e820_type = E820_TYPE_UNUSABLE;
			break;
		case EFI_PERSISTENT_MEMORY:
			e820_type = E820_TYPE_PMEM;
			break;
		default:
			/*
			 * EFI_RESERVED_TYPE EFI_RUNTIME_SERVICES_CODE
			 * EFI_RUNTIME_SERVICES_DATA EFI_MEMORY_MAPPED_IO
			 * EFI_MEMORY_MAPPED_IO_PORT_SPACE EFI_PAL_CODE
			 */
			e820_type = E820_TYPE_RESERVED;
			break;
		}
		e820__range_add(start, size, e820_type);
	}
	e820__update_table(e820_table);
}

Project: tip

int __init efi_memblock_x86_reserve_range(void)
{
	struct efi_info *e = &boot_params.efi_info;
	struct efi_memory_map_data data;
	phys_addr_t pmap;
	int rv;

	if (efi_enabled(EFI_PARAVIRT))
		return 0;

#ifdef CONFIG_X86_32
	/* Can't handle data above 4GB at this time */
	if (e->efi_memmap_hi) {
		pr_err("Memory map is above 4GB, disabling EFI.\n");
		return -EINVAL;
	}
	pmap =  e->efi_memmap;
#else
	pmap = (e->efi_memmap |	((__u64)e->efi_memmap_hi << 32));
#endif
	data.phys_map		= pmap;
	data.size 		= e->efi_memmap_size;
	data.desc_size		= e->efi_memdesc_size;
	data.desc_version	= e->efi_memdesc_version;

	rv = efi_memmap_init_early(&data);
	if (rv)
		return rv;

	if (add_efi_memmap)
		do_add_efi_memmap();

	WARN(efi.memmap.desc_version != 1,
	     "Unexpected EFI_MEMORY_DESCRIPTOR version %ld",
	     efi.memmap.desc_version);

	memblock_reserve(pmap, efi.memmap.nr_map * efi.memmap.desc_size);

	return 0;
}

Project: tip

void __init old_map_region(efi_memory_desc_t *md)
{
	u64 start_pfn, end_pfn, end;
	unsigned long size;
	void *va;

	start_pfn = PFN_DOWN(md->phys_addr);
	size	  = md->num_pages << PAGE_SHIFT;
	end	  = md->phys_addr + size;
	end_pfn   = PFN_UP(end);

	if (pfn_range_is_mapped(start_pfn, end_pfn)) {
		va = __va(md->phys_addr);

		if (!(md->attribute & EFI_MEMORY_WB))
			efi_memory_uc((u64)(unsigned long)va, size);
	} else
		va = efi_ioremap(md->phys_addr, size,
				 md->type, md->attribute);

	md->virt_addr = (u64) (unsigned long) va;
	if (!va)
		pr_err("ioremap of 0x%llX failed!\n",
		       (unsigned long long)md->phys_addr);
}

Project: tip

static unsigned long efi_name_size(efi_char16_t *name)
{
	return ucs2_strsize(name, EFI_VAR_NAME_LEN) + 1;
}

Project: tip

static void *efi_map_next_entry(void *entry)
{
	if (!efi_enabled(EFI_OLD_MEMMAP) && efi_enabled(EFI_64BIT)) {
		/*
		 * Starting in UEFI v2.5 the EFI_PROPERTIES_TABLE
		 * config table feature requires us to map all entries
		 * in the same order as they appear in the EFI memory
		 * map. That is to say, entry N must have a lower
		 * virtual address than entry N+1. This is because the
		 * firmware toolchain leaves relative references in
		 * the code/data sections, which are split and become
		 * separate EFI memory regions. Mapping things
		 * out-of-order leads to the firmware accessing
		 * unmapped addresses.
		 *
		 * Since we need to map things this way whether or not
		 * the kernel actually makes use of
		 * EFI_PROPERTIES_TABLE, let's just switch to this
		 * scheme by default for 64-bit.
		 */
		return efi_map_next_entry_reverse(entry);
	}

	/* Initial call */
	if (!entry)
		return efi.memmap.map;

	entry += efi.memmap.desc_size;
	if (entry >= efi.memmap.map_end)
		return NULL;

	return entry;
}

Project: tip

static int __init arch_parse_efi_cmdline(char *str)
{
	if (!str) {
		pr_warn("need at least one option\n");
		return -EINVAL;
	}

	if (parse_option_str(str, "old_map"))
		set_bit(EFI_OLD_MEMMAP, &efi.flags);

	return 0;
}

Project: tip

efi_thunk_query_variable_info_nonblocking(u32 attr, u64 *storage_space,
					  u64 *remaining_space,
					  u64 *max_variable_size)
{
	efi_status_t status;
	u32 phys_storage, phys_remaining, phys_max;
	unsigned long flags;

	if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
		return EFI_UNSUPPORTED;

	if (!spin_trylock_irqsave(&efi_runtime_lock, flags))
		return EFI_NOT_READY;

	phys_storage = virt_to_phys_or_null(storage_space);
	phys_remaining = virt_to_phys_or_null(remaining_space);
	phys_max = virt_to_phys_or_null(max_variable_size);

	status = efi_thunk(query_variable_info, attr, phys_storage,
			   phys_remaining, phys_max);

	spin_unlock_irqrestore(&efi_runtime_lock, flags);

	return status;
}

Project: tip

int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
{
	unsigned long pfn, text, pf;
	struct page *page;
	unsigned npages;
	pgd_t *pgd = efi_mm.pgd;

	if (efi_enabled(EFI_OLD_MEMMAP))
		return 0;

	/*
	 * It can happen that the physical address of new_memmap lands in memory
	 * which is not mapped in the EFI page table. Therefore we need to go
	 * and ident-map those pages containing the map before calling
	 * phys_efi_set_virtual_address_map().
	 */
	pfn = pa_memmap >> PAGE_SHIFT;
	pf = _PAGE_NX | _PAGE_RW | _PAGE_ENC;
	if (kernel_map_pages_in_pgd(pgd, pfn, pa_memmap, num_pages, pf)) {
		pr_err("Error ident-mapping new memmap (0x%lx)!\n", pa_memmap);
		return 1;
	}

	/*
	 * Certain firmware versions are way too sentimential and still believe
	 * they are exclusive and unquestionable owners of the first physical page,
	 * even though they explicitly mark it as EFI_CONVENTIONAL_MEMORY
	 * (but then write-access it later during SetVirtualAddressMap()).
	 *
	 * Create a 1:1 mapping for this page, to avoid triple faults during early
	 * boot with such firmware. We are free to hand this page to the BIOS,
	 * as trim_bios_range() will reserve the first page and isolate it away
	 * from memory allocators anyway.
	 */
	pf = _PAGE_RW;
	if (sev_active())
		pf |= _PAGE_ENC;

	if (kernel_map_pages_in_pgd(pgd, 0x0, 0x0, 1, pf)) {
		pr_err("Failed to create 1:1 mapping for the first page!\n");
		return 1;
	}

	/*
	 * When making calls to the firmware everything needs to be 1:1
	 * mapped and addressable with 32-bit pointers. Map the kernel
	 * text and allocate a new stack because we can't rely on the
	 * stack pointer being < 4GB.
	 */
	if (!IS_ENABLED(CONFIG_EFI_MIXED) || efi_is_native())
		return 0;

	page = alloc_page(GFP_KERNEL|__GFP_DMA32);
	if (!page)
		panic("Unable to allocate EFI runtime stack < 4GB\n");

	efi_scratch.phys_stack = virt_to_phys(page_address(page));
	efi_scratch.phys_stack += PAGE_SIZE; /* stack grows down */

	npages = (_etext - _text) >> PAGE_SHIFT;
	text = __pa(_text);
	pfn = text >> PAGE_SHIFT;

	pf = _PAGE_RW | _PAGE_ENC;
	if (kernel_map_pages_in_pgd(pgd, pfn, text, npages, pf)) {
		pr_err("Failed to map kernel text 1:1\n");
		return 1;
	}

	return 0;
}

Project: tip

static void __init efi_merge_regions(void)
{
	efi_memory_desc_t *md, *prev_md = NULL;

	for_each_efi_memory_desc(md) {
		u64 prev_size;

		if (!prev_md) {
			prev_md = md;
			continue;
		}

		if (prev_md->type != md->type ||
		    prev_md->attribute != md->attribute) {
			prev_md = md;
			continue;
		}

		prev_size = prev_md->num_pages << EFI_PAGE_SHIFT;

		if (md->phys_addr == (prev_md->phys_addr + prev_size)) {
			prev_md->num_pages += md->num_pages;
			md->type = EFI_RESERVED_TYPE;
			md->attribute = 0;
			continue;
		}
		prev_md = md;
	}
}