Merge tag 'efi-riscv-shared-for-v5.10' of ssh://gitolite.kernel.org/p…

…ub/scm/linux/kernel/git/efi/efi into for-next

Stable branch for v5.10 shared between the EFI and RISC-V trees

The RISC-V EFI boot and runtime support will be merged for v5.10 via
the RISC-V tree. However, it incorporates some changes that conflict
with other EFI changes that are in flight, so this tag serves as a
shared base that allows those conflicts to be resolved beforehand.

* tag 'efi-riscv-shared-for-v5.10' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/efi/efi:
  efi/libstub: arm32: Use low allocation for the uncompressed kernel
  efi/libstub: Export efi_low_alloc_above() to other units
  efi/libstub: arm32: Base FDT and initrd placement on image address
  efi: Rename arm-init to efi-init common for all arch
  include: pe.h: Add RISC-V related PE definition

arch/arm/include/asm/efi.h

@@ -66,25 +66,24 @@ static inline void efifb_setup_from_dmi(struct screen_info *si, const char *opt)
 #define MAX_UNCOMP_KERNEL_SIZE	SZ_32M
 
 /*
- * The kernel zImage should preferably be located between 32 MB and 128 MB
- * from the base of DRAM. The min address leaves space for a maximal size
- * uncompressed image, and the max address is due to how the zImage decompressor
- * picks a destination address.
+ * phys-to-virt patching requires that the physical to virtual offset fits
+ * into the immediate field of an add/sub instruction, which comes down to the
+ * 24 least significant bits being zero, and so the offset should be a multiple
+ * of 16 MB. Since PAGE_OFFSET itself is a multiple of 16 MB, the physical
+ * base should be aligned to 16 MB as well.
  */
-#define ZIMAGE_OFFSET_LIMIT	SZ_128M
-#define MIN_ZIMAGE_OFFSET	MAX_UNCOMP_KERNEL_SIZE
+#define EFI_PHYS_ALIGN		SZ_16M
 
-/* on ARM, the FDT should be located in the first 128 MB of RAM */
-static inline unsigned long efi_get_max_fdt_addr(unsigned long dram_base)
+/* on ARM, the FDT should be located in a lowmem region */
+static inline unsigned long efi_get_max_fdt_addr(unsigned long image_addr)
 {
-	return dram_base + ZIMAGE_OFFSET_LIMIT;
+	return round_down(image_addr, EFI_PHYS_ALIGN) + SZ_512M;
 }
 
 /* on ARM, the initrd should be loaded in a lowmem region */
-static inline unsigned long efi_get_max_initrd_addr(unsigned long dram_base,
-						    unsigned long image_addr)
+static inline unsigned long efi_get_max_initrd_addr(unsigned long image_addr)
 {
-	return dram_base + SZ_512M;
+	return round_down(image_addr, EFI_PHYS_ALIGN) + SZ_512M;
 }
 
 struct efi_arm_entry_state {

arch/arm64/include/asm/efi.h

@@ -65,7 +65,7 @@ efi_status_t __efi_rt_asm_wrapper(void *, const char *, ...);
 	(SEGMENT_ALIGN > THREAD_ALIGN ? SEGMENT_ALIGN : THREAD_ALIGN)
 
 /* on arm64, the FDT may be located anywhere in system RAM */
-static inline unsigned long efi_get_max_fdt_addr(unsigned long dram_base)
+static inline unsigned long efi_get_max_fdt_addr(unsigned long image_addr)
 {
 	return ULONG_MAX;
 }
@@ -80,8 +80,7 @@ static inline unsigned long efi_get_max_fdt_addr(unsigned long dram_base)
  * apply to other bootloaders, and are required for some kernel
  * configurations.
  */
-static inline unsigned long efi_get_max_initrd_addr(unsigned long dram_base,
-						    unsigned long image_addr)
+static inline unsigned long efi_get_max_initrd_addr(unsigned long image_addr)
 {
 	return (image_addr & ~(SZ_1G - 1UL)) + (1UL << (VA_BITS_MIN - 1));
 }

drivers/firmware/efi/Makefile

@@ -32,7 +32,7 @@ obj-$(CONFIG_EFI_EMBEDDED_FIRMWARE)	+= embedded-firmware.o
 fake_map-y				+= fake_mem.o
 fake_map-$(CONFIG_X86)			+= x86_fake_mem.o
 
-arm-obj-$(CONFIG_EFI)			:= arm-init.o arm-runtime.o
+arm-obj-$(CONFIG_EFI)			:= efi-init.o arm-runtime.o
 obj-$(CONFIG_ARM)			+= $(arm-obj-y)
 obj-$(CONFIG_ARM64)			+= $(arm-obj-y)
 obj-$(CONFIG_EFI_CAPSULE_LOADER)	+= capsule-loader.o

drivers/firmware/efi/libstub/arm32-stub.c

@@ -113,162 +113,58 @@ void free_screen_info(struct screen_info *si)
 	efi_bs_call(free_pool, si);
 }
 
-static efi_status_t reserve_kernel_base(unsigned long dram_base,
-					unsigned long *reserve_addr,
-					unsigned long *reserve_size)
-{
-	efi_physical_addr_t alloc_addr;
-	efi_memory_desc_t *memory_map;
-	unsigned long nr_pages, map_size, desc_size, buff_size;
-	efi_status_t status;
-	unsigned long l;
-
-	struct efi_boot_memmap map = {
-		.map		= &memory_map,
-		.map_size	= &map_size,
-		.desc_size	= &desc_size,
-		.desc_ver	= NULL,
-		.key_ptr	= NULL,
-		.buff_size	= &buff_size,
-	};
-
-	/*
-	 * Reserve memory for the uncompressed kernel image. This is
-	 * all that prevents any future allocations from conflicting
-	 * with the kernel. Since we can't tell from the compressed
-	 * image how much DRAM the kernel actually uses (due to BSS
-	 * size uncertainty) we allocate the maximum possible size.
-	 * Do this very early, as prints can cause memory allocations
-	 * that may conflict with this.
-	 */
-	alloc_addr = dram_base + MAX_UNCOMP_KERNEL_SIZE;
-	nr_pages = MAX_UNCOMP_KERNEL_SIZE / EFI_PAGE_SIZE;
-	status = efi_bs_call(allocate_pages, EFI_ALLOCATE_MAX_ADDRESS,
-			     EFI_BOOT_SERVICES_DATA, nr_pages, &alloc_addr);
-	if (status == EFI_SUCCESS) {
-		if (alloc_addr == dram_base) {
-			*reserve_addr = alloc_addr;
-			*reserve_size = MAX_UNCOMP_KERNEL_SIZE;
-			return EFI_SUCCESS;
-		}
-		/*
-		 * If we end up here, the allocation succeeded but starts below
-		 * dram_base. This can only occur if the real base of DRAM is
-		 * not a multiple of 128 MB, in which case dram_base will have
-		 * been rounded up. Since this implies that a part of the region
-		 * was already occupied, we need to fall through to the code
-		 * below to ensure that the existing allocations don't conflict.
-		 * For this reason, we use EFI_BOOT_SERVICES_DATA above and not
-		 * EFI_LOADER_DATA, which we wouldn't able to distinguish from
-		 * allocations that we want to disallow.
-		 */
-	}
-
-	/*
-	 * If the allocation above failed, we may still be able to proceed:
-	 * if the only allocations in the region are of types that will be
-	 * released to the OS after ExitBootServices(), the decompressor can
-	 * safely overwrite them.
-	 */
-	status = efi_get_memory_map(&map);
-	if (status != EFI_SUCCESS) {
-		efi_err("reserve_kernel_base(): Unable to retrieve memory map.\n");
-		return status;
-	}
-
-	for (l = 0; l < map_size; l += desc_size) {
-		efi_memory_desc_t *desc;
-		u64 start, end;
-
-		desc = (void *)memory_map + l;
-		start = desc->phys_addr;
-		end = start + desc->num_pages * EFI_PAGE_SIZE;
-
-		/* Skip if entry does not intersect with region */
-		if (start >= dram_base + MAX_UNCOMP_KERNEL_SIZE ||
-		    end <= dram_base)
-			continue;
-
-		switch (desc->type) {
-		case EFI_BOOT_SERVICES_CODE:
-		case EFI_BOOT_SERVICES_DATA:
-			/* Ignore types that are released to the OS anyway */
-			continue;
-
-		case EFI_CONVENTIONAL_MEMORY:
-			/* Skip soft reserved conventional memory */
-			if (efi_soft_reserve_enabled() &&
-			    (desc->attribute & EFI_MEMORY_SP))
-				continue;
-
-			/*
-			 * Reserve the intersection between this entry and the
-			 * region.
-			 */
-			start = max(start, (u64)dram_base);
-			end = min(end, (u64)dram_base + MAX_UNCOMP_KERNEL_SIZE);
-
-			status = efi_bs_call(allocate_pages,
-					     EFI_ALLOCATE_ADDRESS,
-					     EFI_LOADER_DATA,
-					     (end - start) / EFI_PAGE_SIZE,
-					     &start);
-			if (status != EFI_SUCCESS) {
-				efi_err("reserve_kernel_base(): alloc failed.\n");
-				goto out;
-			}
-			break;
-
-		case EFI_LOADER_CODE:
-		case EFI_LOADER_DATA:
-			/*
-			 * These regions may be released and reallocated for
-			 * another purpose (including EFI_RUNTIME_SERVICE_DATA)
-			 * at any time during the execution of the OS loader,
-			 * so we cannot consider them as safe.
-			 */
-		default:
-			/*
-			 * Treat any other allocation in the region as unsafe */
-			status = EFI_OUT_OF_RESOURCES;
-			goto out;
-		}
-	}
-
-	status = EFI_SUCCESS;
-out:
-	efi_bs_call(free_pool, memory_map);
-	return status;
-}
-
 efi_status_t handle_kernel_image(unsigned long *image_addr,
 				 unsigned long *image_size,
 				 unsigned long *reserve_addr,
 				 unsigned long *reserve_size,
-				 unsigned long dram_base,
 				 efi_loaded_image_t *image)
 {
-	unsigned long kernel_base;
+	const int slack = TEXT_OFFSET - 5 * PAGE_SIZE;
+	int alloc_size = MAX_UNCOMP_KERNEL_SIZE + EFI_PHYS_ALIGN;
+	unsigned long alloc_base, kernel_base;
 	efi_status_t status;
 
-	/* use a 16 MiB aligned base for the decompressed kernel */
-	kernel_base = round_up(dram_base, SZ_16M) + TEXT_OFFSET;
-
 	/*
-	 * Note that some platforms (notably, the Raspberry Pi 2) put
-	 * spin-tables and other pieces of firmware at the base of RAM,
-	 * abusing the fact that the window of TEXT_OFFSET bytes at the
-	 * base of the kernel image is only partially used at the moment.
-	 * (Up to 5 pages are used for the swapper page tables)
+	 * Allocate space for the decompressed kernel as low as possible.
+	 * The region should be 16 MiB aligned, but the first 'slack' bytes
+	 * are not used by Linux, so we allow those to be occupied by the
+	 * firmware.
 	 */
-	status = reserve_kernel_base(kernel_base - 5 * PAGE_SIZE, reserve_addr,
-				     reserve_size);
+	status = efi_low_alloc_above(alloc_size, EFI_PAGE_SIZE, &alloc_base, 0x0);
 	if (status != EFI_SUCCESS) {
 		efi_err("Unable to allocate memory for uncompressed kernel.\n");
 		return status;
 	}
 
-	*image_addr = kernel_base;
+	if ((alloc_base % EFI_PHYS_ALIGN) > slack) {
+		/*
+		 * More than 'slack' bytes are already occupied at the base of
+		 * the allocation, so we need to advance to the next 16 MiB block.
+		 */
+		kernel_base = round_up(alloc_base, EFI_PHYS_ALIGN);
+		efi_info("Free memory starts at 0x%lx, setting kernel_base to 0x%lx\n",
+			 alloc_base, kernel_base);
+	} else {
+		kernel_base = round_down(alloc_base, EFI_PHYS_ALIGN);
+	}
+
+	*reserve_addr = kernel_base + slack;
+	*reserve_size = MAX_UNCOMP_KERNEL_SIZE;
+
+	/* now free the parts that we will not use */
+	if (*reserve_addr > alloc_base) {
+		efi_bs_call(free_pages, alloc_base,
+			    (*reserve_addr - alloc_base) / EFI_PAGE_SIZE);
+		alloc_size -= *reserve_addr - alloc_base;
+	}
+	efi_bs_call(free_pages, *reserve_addr + MAX_UNCOMP_KERNEL_SIZE,
+		    (alloc_size - MAX_UNCOMP_KERNEL_SIZE) / EFI_PAGE_SIZE);
+
+	*image_addr = kernel_base + TEXT_OFFSET;
 	*image_size = 0;
+
+	efi_debug("image addr == 0x%lx, reserve_addr == 0x%lx\n",
+		  *image_addr, *reserve_addr);
+
 	return EFI_SUCCESS;
 }

drivers/firmware/efi/libstub/arm64-stub.c

@@ -50,7 +50,6 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
 				 unsigned long *image_size,
 				 unsigned long *reserve_addr,
 				 unsigned long *reserve_size,
-				 unsigned long dram_base,
 				 efi_loaded_image_t *image)
 {
 	efi_status_t status;

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

@@ -87,40 +87,6 @@ static void install_memreserve_table(void)
 		efi_err("Failed to install memreserve config table!\n");
 }
 
-static unsigned long get_dram_base(void)
-{
-	efi_status_t status;
-	unsigned long map_size, buff_size;
-	unsigned long membase  = EFI_ERROR;
-	struct efi_memory_map map;
-	efi_memory_desc_t *md;
-	struct efi_boot_memmap boot_map;
-
-	boot_map.map		= (efi_memory_desc_t **)&map.map;
-	boot_map.map_size	= &map_size;
-	boot_map.desc_size	= &map.desc_size;
-	boot_map.desc_ver	= NULL;
-	boot_map.key_ptr	= NULL;
-	boot_map.buff_size	= &buff_size;
-
-	status = efi_get_memory_map(&boot_map);
-	if (status != EFI_SUCCESS)
-		return membase;
-
-	map.map_end = map.map + map_size;
-
-	for_each_efi_memory_desc_in_map(&map, md) {
-		if (md->attribute & EFI_MEMORY_WB) {
-			if (membase > md->phys_addr)
-				membase = md->phys_addr;
-		}
-	}
-
-	efi_bs_call(free_pool, map.map);
-
-	return membase;
-}
-
 /*
  * EFI entry point for the arm/arm64 EFI stubs.  This is the entrypoint
  * that is described in the PE/COFF header.  Most of the code is the same
@@ -134,7 +100,6 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
 	efi_status_t status;
 	unsigned long image_addr;
 	unsigned long image_size = 0;
-	unsigned long dram_base;
 	/* addr/point and size pairs for memory management*/
 	unsigned long initrd_addr = 0;
 	unsigned long initrd_size = 0;
@@ -174,13 +139,6 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
 		goto fail;
 	}
 
-	dram_base = get_dram_base();
-	if (dram_base == EFI_ERROR) {
-		efi_err("Failed to find DRAM base\n");
-		status = EFI_LOAD_ERROR;
-		goto fail;
-	}
-
 	/*
 	 * Get the command line from EFI, using the LOADED_IMAGE
 	 * protocol. We are going to copy the command line into the
@@ -218,7 +176,7 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
 	status = handle_kernel_image(&image_addr, &image_size,
 				     &reserve_addr,
 				     &reserve_size,
-				     dram_base, image);
+				     image);
 	if (status != EFI_SUCCESS) {
 		efi_err("Failed to relocate kernel\n");
 		goto fail_free_screeninfo;
@@ -262,7 +220,7 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
 		efi_info("Generating empty DTB\n");
 
 	if (!efi_noinitrd) {
-		max_addr = efi_get_max_initrd_addr(dram_base, image_addr);
+		max_addr = efi_get_max_initrd_addr(image_addr);
 		status = efi_load_initrd(image, &initrd_addr, &initrd_size,
 					 ULONG_MAX, max_addr);
 		if (status != EFI_SUCCESS)
@@ -306,7 +264,7 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
 	install_memreserve_table();
 
 	status = allocate_new_fdt_and_exit_boot(handle, &fdt_addr,
-						efi_get_max_fdt_addr(dram_base),
+						efi_get_max_fdt_addr(image_addr),
 						initrd_addr, initrd_size,
 						cmdline_ptr, fdt_addr, fdt_size);
 	if (status != EFI_SUCCESS)

drivers/firmware/efi/libstub/efistub.h

@@ -10,9 +10,6 @@
 #include <linux/types.h>
 #include <asm/efi.h>
 
-/* error code which can't be mistaken for valid address */
-#define EFI_ERROR	(~0UL)
-
 /*
  * __init annotations should not be used in the EFI stub, since the code is
  * either included in the decompressor (x86, ARM) where they have no effect,
@@ -740,6 +737,9 @@ efi_status_t efi_allocate_pages(unsigned long size, unsigned long *addr,
 efi_status_t efi_allocate_pages_aligned(unsigned long size, unsigned long *addr,
 					unsigned long max, unsigned long align);
 
+efi_status_t efi_low_alloc_above(unsigned long size, unsigned long align,
+				 unsigned long *addr, unsigned long min);
+
 efi_status_t efi_relocate_kernel(unsigned long *image_addr,
 				 unsigned long image_size,
 				 unsigned long alloc_size,
@@ -786,7 +786,6 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
 				 unsigned long *image_size,
 				 unsigned long *reserve_addr,
 				 unsigned long *reserve_size,
-				 unsigned long dram_base,
 				 efi_loaded_image_t *image);
 
 asmlinkage void __noreturn efi_enter_kernel(unsigned long entrypoint,