efi/x86: Decompress at start of PE image load address (1887c9b6) · Commits · 戴 / test

arch/x86/boot/compressed/head_32.S

+17 −0

Original line number	Diff line number	Diff line
		@@ -100,6 +100,19 @@ SYM_FUNC_START(startup_32)

		#ifdef CONFIG_RELOCATABLE
		movl %edx, %ebx

		#ifdef CONFIG_EFI_STUB
		/*
		* If we were loaded via the EFI LoadImage service, startup_32() will be at an
		* offset to the start of the space allocated for the image. efi_pe_entry() will
		* set up image_offset to tell us where the image actually starts, so that we
		* can use the full available buffer.
		* image_offset = startup_32 - image_base
		* Otherwise image_offset will be zero and has no effect on the calculations.
		*/
		subl image_offset(%edx), %ebx
		#endif

		movl BP_kernel_alignment(%esi), %eax
		decl %eax
		addl %eax, %ebx
		@@ -226,6 +239,10 @@ SYM_DATA_START_LOCAL(gdt)
		.quad 0x00cf92000000ffff /* __KERNEL_DS */
		SYM_DATA_END_LABEL(gdt, SYM_L_LOCAL, gdt_end)

		#ifdef CONFIG_EFI_STUB
		SYM_DATA(image_offset, .long 0)
		#endif

		/*
		* Stack and heap for uncompression
		*/

arch/x86/boot/compressed/head_64.S

+39 −3

Original line number	Diff line number	Diff line
		@@ -99,6 +99,19 @@ SYM_FUNC_START(startup_32)

		#ifdef CONFIG_RELOCATABLE
		movl %ebp, %ebx

		#ifdef CONFIG_EFI_STUB
		/*
		* If we were loaded via the EFI LoadImage service, startup_32 will be at an
		* offset to the start of the space allocated for the image. efi_pe_entry will
		* set up image_offset to tell us where the image actually starts, so that we
		* can use the full available buffer.
		* image_offset = startup_32 - image_base
		* Otherwise image_offset will be zero and has no effect on the calculations.
		*/
		subl image_offset(%ebp), %ebx
		#endif

		movl BP_kernel_alignment(%esi), %eax
		decl %eax
		addl %eax, %ebx
		@@ -111,9 +124,8 @@ SYM_FUNC_START(startup_32)
		1:

		/* Target address to relocate to for decompression */
		movl BP_init_size(%esi), %eax
		subl $_end, %eax
		addl %eax, %ebx
		addl BP_init_size(%esi), %ebx
		subl $_end, %ebx

		/*
		* Prepare for entering 64 bit mode
		@@ -299,6 +311,20 @@ SYM_CODE_START(startup_64)
		/* Start with the delta to where the kernel will run at. */
		#ifdef CONFIG_RELOCATABLE
		leaq startup_32(%rip) /* - $startup_32 */, %rbp

		#ifdef CONFIG_EFI_STUB
		/*
		* If we were loaded via the EFI LoadImage service, startup_32 will be at an
		* offset to the start of the space allocated for the image. efi_pe_entry will
		* set up image_offset to tell us where the image actually starts, so that we
		* can use the full available buffer.
		* image_offset = startup_32 - image_base
		* Otherwise image_offset will be zero and has no effect on the calculations.
		*/
		movl image_offset(%rip), %eax
		subq %rax, %rbp
		#endif

		movl BP_kernel_alignment(%rsi), %eax
		decl %eax
		addq %rax, %rbp
		@@ -647,6 +673,10 @@ SYM_DATA_START_LOCAL(gdt)
		.quad 0x0000000000000000 /* TS continued */
		SYM_DATA_END_LABEL(gdt, SYM_L_LOCAL, gdt_end)

		#ifdef CONFIG_EFI_STUB
		SYM_DATA(image_offset, .long 0)
		#endif

		#ifdef CONFIG_EFI_MIXED
		SYM_DATA_LOCAL(efi32_boot_args, .long 0, 0, 0)
		SYM_DATA(efi_is64, .byte 1)
		@@ -712,6 +742,12 @@ SYM_FUNC_START(efi32_pe_entry)
		movl -4(%ebp), %esi // loaded_image
		movl LI32_image_base(%esi), %esi // loaded_image->image_base
		movl %ebx, %ebp // startup_32 for efi32_pe_stub_entry
		/*
		* We need to set the image_offset variable here since startup_32() will
		* use it before we get to the 64-bit efi_pe_entry() in C code.
		*/
		subl %esi, %ebx
		movl %ebx, image_offset(%ebp) // save image_offset
		jmp efi32_pe_stub_entry

		2: popl %edi // restore callee-save registers

drivers/firmware/efi/libstub/x86-stub.c

+14 −3

Original line number	Diff line number	Diff line
		@@ -19,6 +19,7 @@

		static efi_system_table_t *sys_table;
		extern const bool efi_is64;
		extern u32 image_offset;

		__pure efi_system_table_t *efi_system_table(void)
		{
		@@ -365,6 +366,7 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
		struct boot_params *boot_params;
		struct setup_header *hdr;
		efi_loaded_image_t *image;
		void *image_base;
		efi_guid_t proto = LOADED_IMAGE_PROTOCOL_GUID;
		int options_size = 0;
		efi_status_t status;
		@@ -385,7 +387,10 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
		efi_exit(handle, status);
		}

		hdr = &((struct boot_params *)efi_table_attr(image, image_base))->hdr;
		image_base = efi_table_attr(image, image_base);
		image_offset = (void *)startup_32 - image_base;

		hdr = &((struct boot_params *)image_base)->hdr;
		above4g = hdr->xloadflags & XLF_CAN_BE_LOADED_ABOVE_4G;

		status = efi_allocate_pages(0x4000, (unsigned long *)&boot_params,
		@@ -400,7 +405,7 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
		hdr = &boot_params->hdr;

		/* Copy the second sector to boot_params */
		memcpy(&hdr->jump, efi_table_attr(image, image_base) + 512, 512);
		memcpy(&hdr->jump, image_base + 512, 512);

		/*
		* Fill out some of the header fields ourselves because the
		@@ -727,7 +732,7 @@ unsigned long efi_main(efi_handle_t handle,
		* If the kernel isn't already loaded at the preferred load
		* address, relocate it.
		*/
		if (bzimage_addr != hdr->pref_address) {
		if (bzimage_addr - image_offset != hdr->pref_address) {
		status = efi_relocate_kernel(&bzimage_addr,
		hdr->init_size, hdr->init_size,
		hdr->pref_address,
		@@ -737,6 +742,12 @@ unsigned long efi_main(efi_handle_t handle,
		efi_printk("efi_relocate_kernel() failed!\n");
		goto fail;
		}
		/*
		* Now that we've copied the kernel elsewhere, we no longer
		* have a set up block before startup_32(), so reset image_offset
		* to zero in case it was set earlier.
		*/
		image_offset = 0;
		}

		/*

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