arm64/efi: move SetVirtualAddressMap() to UEFI stub (f3cdfd23) · Commits · 戴 / test

arch/arm64/include/asm/efi.h

+32 −2

Original line number	Diff line number	Diff line
		@@ -7,28 +7,36 @@
		#ifdef CONFIG_EFI
		extern void efi_init(void);
		extern void efi_idmap_init(void);
		extern void efi_virtmap_init(void);
		#else
		#define efi_init()
		#define efi_idmap_init()
		#define efi_virtmap_init()
		#endif

		#define efi_call_virt(f, ...) \
		({ \
		efi_##f##_t *__f = efi.systab->runtime->f; \
		efi_##f##_t *__f; \
		efi_status_t __s; \
		\
		kernel_neon_begin(); \
		efi_virtmap_load(); \
		__f = efi.systab->runtime->f; \
		__s = __f(__VA_ARGS__); \
		efi_virtmap_unload(); \
		kernel_neon_end(); \
		__s; \
		})

		#define __efi_call_virt(f, ...) \
		({ \
		efi_##f##_t *__f = efi.systab->runtime->f; \
		efi_##f##_t *__f; \
		\
		kernel_neon_begin(); \
		efi_virtmap_load(); \
		__f = efi.systab->runtime->f; \
		__f(__VA_ARGS__); \
		efi_virtmap_unload(); \
		kernel_neon_end(); \
		})

		@@ -46,4 +54,26 @@ extern void efi_idmap_init(void);

		#define EFI_ALLOC_ALIGN SZ_64K

		/*
		* On ARM systems, virtually remapped UEFI runtime services are set up in three
		* distinct stages:
		* - The stub retrieves the final version of the memory map from UEFI, populates
		* the virt_addr fields and calls the SetVirtualAddressMap() [SVAM] runtime
		* service to communicate the new mapping to the firmware (Note that the new
		* mapping is not live at this time)
		* - During early boot, the page tables are allocated and populated based on the
		* virt_addr fields in the memory map, but only if all descriptors with the
		* EFI_MEMORY_RUNTIME attribute have a non-zero value for virt_addr. If this
		* succeeds, the EFI_VIRTMAP flag is set to indicate that the virtual mappings
		* have been installed successfully.
		* - During an early initcall(), the UEFI Runtime Services are enabled and the
		* EFI_RUNTIME_SERVICES bit set if some conditions are met, i.e., we need a
		* non-early mapping of the UEFI system table, and we need to have the virtmap
		* installed.
		*/
		#define EFI_VIRTMAP EFI_ARCH_1

		void efi_virtmap_load(void);
		void efi_virtmap_unload(void);

		#endif /* _ASM_EFI_H */

arch/arm64/kernel/efi.c

+127 −103

Original line number	Diff line number	Diff line
		@@ -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;
		@@ -329,51 +365,14 @@ void __init efi_idmap_init(void)
		early_memunmap(memmap.map, memmap.map_end - memmap.map);
		}

		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);
		}

arch/arm64/kernel/setup.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -401,6 +401,7 @@ void __init setup_arch(char **cmdline_p)
		paging_init();
		request_standard_resources();

		efi_virtmap_init();
		efi_idmap_init();
		early_ioremap_reset();

drivers/firmware/efi/libstub/arm-stub.c

+59 −0

Original line number	Diff line number	Diff line
		@@ -295,3 +295,62 @@ fail_free_image:
		fail:
		return EFI_ERROR;
		}

		/*
		* This is the base address at which to start allocating virtual memory ranges
		* for UEFI Runtime Services. This is in the low TTBR0 range so that we can use
		* any allocation we choose, and eliminate the risk of a conflict after kexec.
		* The value chosen is the largest non-zero power of 2 suitable for this purpose
		* both on 32-bit and 64-bit ARM CPUs, to maximize the likelihood that it can
		* be mapped efficiently.
		*/
		#define EFI_RT_VIRTUAL_BASE 0x40000000

		/*
		* efi_get_virtmap() - create a virtual mapping for the EFI memory map
		*
		* This function populates the virt_addr fields of all memory region descriptors
		* in @memory_map whose EFI_MEMORY_RUNTIME attribute is set. Those descriptors
		* are also copied to @runtime_map, and their total count is returned in @count.
		*/
		void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size,
		unsigned long desc_size, efi_memory_desc_t *runtime_map,
		int *count)
		{
		u64 efi_virt_base = EFI_RT_VIRTUAL_BASE;
		efi_memory_desc_t *out = runtime_map;
		int l;

		for (l = 0; l < map_size; l += desc_size) {
		efi_memory_desc_t in = (void )memory_map + l;
		u64 paddr, size;

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

		/*
		* Make the mapping compatible with 64k pages: this allows
		* a 4k page size kernel to kexec a 64k page size kernel and
		* vice versa.
		*/
		paddr = round_down(in->phys_addr, SZ_64K);
		size = round_up(in->num_pages * EFI_PAGE_SIZE +
		in->phys_addr - paddr, SZ_64K);

		/*
		* Avoid wasting memory on PTEs by choosing a virtual base that
		* is compatible with section mappings if this region has the
		* appropriate size and physical alignment. (Sections are 2 MB
		* on 4k granule kernels)
		*/
		if (IS_ALIGNED(in->phys_addr, SZ_2M) && size >= SZ_2M)
		efi_virt_base = round_up(efi_virt_base, SZ_2M);

		in->virt_addr = efi_virt_base + in->phys_addr - paddr;
		efi_virt_base += size;

		memcpy(out, in, desc_size);
		out = (void *)out + desc_size;
		++*count;
		}
		}

drivers/firmware/efi/libstub/efistub.h

+4 −0

Original line number	Diff line number	Diff line
		@@ -39,4 +39,8 @@ efi_status_t allocate_new_fdt_and_exit_boot(efi_system_table_t *sys_table,

		void get_fdt(efi_system_table_t sys_table);

		void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size,
		unsigned long desc_size, efi_memory_desc_t *runtime_map,
		int *count);

		#endif

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