Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752340AbbBWDpM (ORCPT ); Sun, 22 Feb 2015 22:45:12 -0500 Received: from userp1040.oracle.com ([156.151.31.81]:23049 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751573AbbBWDpJ (ORCPT ); Sun, 22 Feb 2015 22:45:09 -0500 From: Yinghai Lu To: Thomas Gleixner , "H. Peter Anvin" , Ingo Molnar , Jonathan Corbet , Matt Fleming Cc: Kees Cook , Junjie Mao , linux-doc@vger.kernel.org, linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, Yinghai Lu Subject: [PATCH v2] x86, boot: Allow 64bit EFI kernel to be loaded above 4G Date: Sun, 22 Feb 2015 19:43:48 -0800 Message-Id: <1424663028-13066-1-git-send-email-yinghai@kernel.org> X-Mailer: git-send-email 1.8.4.5 X-Source-IP: ucsinet21.oracle.com [156.151.31.93] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8356 Lines: 222 Now could use kexec to place kernel/boot_params/cmd_line/initrd above 4G, but that is with legacy interface with startup_64 directly. This patch will allow 64bit EFI kernel to be loaded above 4G and use EFI HANDOVER PROTOCOL to start the kernel. Current 32bit code32_start is used for passing around load address, so it will overflow when kernel is loaded abover 4G. The patch mainly add ext_code32_start to take load address high 32bits. After this patch, could use patched grub2-x86_64.efi to place kernel/boot_params/cmd_line/initrd all above 4G and execute the kernel above 4G. bootlog like: kernel: done [ linux 9.25MiB 100% 6.66MiB/s ] params: [1618fc000,1618fffff] cmdline: [1618fb000,1618fb7fe] kernel: [15e000000,161385fff] initrd: [15bcbe000,15dffffbb] initrd: 1 file done [ initrd.img 35.26MiB 100% 11.93MiB/s ] early console in decompress_kernel decompress_kernel: input: [0x15fd0b3b4-0x16063c803], output: 0x15e000000, heap: [0x160645b00-0x16064daff] Decompressing Linux... xz... Parsing ELF... done. Booting the kernel. [ 0.000000] bootconsole [uart0] enabled [ 0.000000] real_mode_data : phys 00000001618fc000 [ 0.000000] real_mode_data : virt ffff8801618fc000 [ 0.000000] Kernel Layout: [ 0.000000] .text: [0x15e000000-0x15f08f72c] [ 0.000000] .rodata: [0x15f200000-0x15fa44fff] [ 0.000000] .data: [0x15fc00000-0x15fe545ff] [ 0.000000] .init: [0x15fe56000-0x16021afff] [ 0.000000] .bss: [0x160229000-0x16135ffff] [ 0.000000] .brk: [0x161360000-0x161385fff] [ 0.000000] memblock_reserve: [0x0000000009f000-0x000000000fffff] flags 0x0 * BIOS reserved ... [ 0.000000] memblock_reserve: [0x0000015e000000-0x0000016135ffff] flags 0x0 TEXT DATA BSS [ 0.000000] memblock_reserve: [0x0000015bcbe000-0x0000015dffffff] flags 0x0 RAMDISK -v2: add cast to avoid warning with 32bit, also update description for ext_code32_start in boot.txt Signed-off-by: Yinghai Lu --- Documentation/x86/boot.txt | 19 +++++++++++++++++++ arch/x86/boot/compressed/eboot.c | 15 ++++++++++----- arch/x86/boot/compressed/head_64.S | 7 ++++++- arch/x86/boot/header.S | 3 ++- arch/x86/include/uapi/asm/bootparam.h | 1 + arch/x86/kernel/asm-offsets.c | 1 + 6 files changed, 39 insertions(+), 7 deletions(-) Index: linux-2.6/arch/x86/include/uapi/asm/bootparam.h =================================================================== --- linux-2.6.orig/arch/x86/include/uapi/asm/bootparam.h +++ linux-2.6/arch/x86/include/uapi/asm/bootparam.h @@ -84,6 +84,7 @@ struct setup_header { __u64 pref_address; __u32 init_size; __u32 handover_offset; + __u32 ext_code32_start; } __attribute__((packed)); struct sys_desc_table { Index: linux-2.6/arch/x86/kernel/asm-offsets.c =================================================================== --- linux-2.6.orig/arch/x86/kernel/asm-offsets.c +++ linux-2.6/arch/x86/kernel/asm-offsets.c @@ -68,6 +68,7 @@ void common(void) { OFFSET(BP_kernel_alignment, boot_params, hdr.kernel_alignment); OFFSET(BP_pref_address, boot_params, hdr.pref_address); OFFSET(BP_code32_start, boot_params, hdr.code32_start); + OFFSET(BP_ext_code32_start, boot_params, hdr.ext_code32_start); BLANK(); DEFINE(PTREGS_SIZE, sizeof(struct pt_regs)); Index: linux-2.6/arch/x86/boot/compressed/head_64.S =================================================================== --- linux-2.6.orig/arch/x86/boot/compressed/head_64.S +++ linux-2.6/arch/x86/boot/compressed/head_64.S @@ -264,6 +264,8 @@ ENTRY(efi_pe_entry) mov %rax, %rsi leaq startup_32(%rip), %rax movl %eax, BP_code32_start(%rsi) + shr $32, %rax + movl %eax, BP_ext_code32_start(%rsi) jmp 2f /* Skip the relocation */ handover_entry: @@ -287,7 +289,10 @@ fail: hlt jmp fail 2: - movl BP_code32_start(%esi), %eax + movl BP_code32_start(%rsi), %eax + movl BP_ext_code32_start(%rsi), %ebx + shl $32, %rbx + orq %rbx, %rax leaq preferred_addr(%rax), %rax jmp *%rax Index: linux-2.6/arch/x86/boot/compressed/eboot.c =================================================================== --- linux-2.6.orig/arch/x86/boot/compressed/eboot.c +++ linux-2.6/arch/x86/boot/compressed/eboot.c @@ -1388,6 +1388,7 @@ struct boot_params *efi_main(struct efi_ void *handle; efi_system_table_t *_table; bool is64; + unsigned long loaded_addr; efi_early = c; @@ -1429,9 +1430,12 @@ struct boot_params *efi_main(struct efi_ * If the kernel isn't already loaded at the preferred load * address, relocate it. */ - if (hdr->pref_address != hdr->code32_start) { - unsigned long bzimage_addr = hdr->code32_start; - status = efi_relocate_kernel(sys_table, &bzimage_addr, + loaded_addr = hdr->code32_start; + loaded_addr |= (unsigned long)((u64)hdr->ext_code32_start << 32); + if (hdr->pref_address != loaded_addr) { + unsigned long loaded_addr_orig = loaded_addr; + + status = efi_relocate_kernel(sys_table, &loaded_addr, hdr->init_size, hdr->init_size, hdr->pref_address, hdr->kernel_alignment); @@ -1440,8 +1444,9 @@ struct boot_params *efi_main(struct efi_ goto fail; } - hdr->pref_address = hdr->code32_start; - hdr->code32_start = bzimage_addr; + hdr->pref_address = loaded_addr_orig; + hdr->code32_start = loaded_addr & 0xffffffff; + hdr->ext_code32_start = (unsigned long)((u64)loaded_addr >> 32); } status = exit_boot(boot_params, handle, is64); Index: linux-2.6/arch/x86/boot/header.S =================================================================== --- linux-2.6.orig/arch/x86/boot/header.S +++ linux-2.6/arch/x86/boot/header.S @@ -301,7 +301,7 @@ _start: # Part 2 of the header, from the old setup.S .ascii "HdrS" # header signature - .word 0x020d # header version number (>= 0x0105) + .word 0x020e # header version number (>= 0x0105) # or else old loadlin-1.5 will fail) .globl realmode_swtch realmode_swtch: .word 0, 0 # default_switch, SETUPSEG @@ -449,6 +449,7 @@ pref_address: .quad LOAD_PHYSICAL_ADDR #endif init_size: .long INIT_SIZE # kernel initialization size handover_offset: .long 0 # Filled in by build.c +ext_code32_start: .long 0 # werid one! # End of setup header ##################################################### Index: linux-2.6/Documentation/x86/boot.txt =================================================================== --- linux-2.6.orig/Documentation/x86/boot.txt +++ linux-2.6/Documentation/x86/boot.txt @@ -61,6 +61,9 @@ Protocol 2.12: (Kernel 3.8) Added the xl to struct boot_params for loading bzImage and ramdisk above 4G in 64bit. +Protocol 2.14: (Kernel 3.20) Added the ext_code32_start to support 64bit + EFI kernel to be loaded above 4G. + **** MEMORY LAYOUT The traditional memory map for the kernel loader, used for Image or @@ -197,6 +200,7 @@ Offset Proto Name Meaning 0258/8 2.10+ pref_address Preferred loading address 0260/4 2.10+ init_size Linear memory required during initialization 0264/4 2.11+ handover_offset Offset of handover entry point +0268/4 2.14+ ext_code32_start Extended part for code32_start (1) For backwards compatibility, if the setup_sects field contains 0, the real value is 4. @@ -738,6 +742,14 @@ Offset/size: 0x264/4 See EFI HANDOVER PROTOCOL below for more details. +Field name: ext_code32_start +Type: modify (optional, reloc) +Offset/size: 0x268/4 +Protocol: 2.14+ + + This field is the upper 32bits of load address when EFI 64bit kernel + is loaded above 4G. And it is used with code32_start to compare to + pref_address to decide if kernel need to be relocated further. **** THE IMAGE CHECKSUM @@ -1122,4 +1134,11 @@ The boot loader *must* fill out the foll o hdr.ramdisk_image (if applicable) o hdr.ramdisk_size (if applicable) +for 64bit, when loading above 4G, *must* fill out the following fields, + + o hdr.ext_code32_start + o ext_cmd_line_ptr + o ext_ramdisk_image (if applicable) + o ext_ramdisk_size (if applicable) + All other fields should be zero. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/