From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757324AbbGGXMe (ORCPT ); Tue, 7 Jul 2015 19:12:34 -0400 Received: from mail-ie0-f181.google.com ([209.85.223.181]:34114 "EHLO mail-ie0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932247AbbGGXM1 (ORCPT ); Tue, 7 Jul 2015 19:12:27 -0400 MIME-Version: 1.0 In-Reply-To: <1436300428-21163-29-git-send-email-yinghai@kernel.org> References: <1436300428-21163-1-git-send-email-yinghai@kernel.org> <1436300428-21163-29-git-send-email-yinghai@kernel.org> Date: Tue, 7 Jul 2015 16:12:26 -0700 X-Google-Sender-Auth: P0akEdDDdeDurEOTRc3XtSCs_G4 Message-ID: Subject: Re: [PATCH 28/42] x86, boot: Allow 64bit EFI kernel to be loaded above 4G From: Kees Cook To: Yinghai Lu Cc: "H. Peter Anvin" , Baoquan He , LKML Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 7, 2015 at 1:20 PM, Yinghai Lu wrote: > 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 > -v3: change to 4.0 from 3.20. > > 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(-) > > diff --git a/Documentation/x86/boot.txt b/Documentation/x86/boot.txt > index 9da6f35..90efaa2 100644 > --- a/Documentation/x86/boot.txt > +++ b/Documentation/x86/boot.txt > @@ -61,6 +61,9 @@ Protocol 2.12: (Kernel 3.8) Added the xloadflags field and extension fields > to struct boot_params for loading bzImage and ramdisk > above 4G in 64bit. > > +Protocol 2.14: (Kernel 4.0) Added the ext_code32_start to support 64bit > + EFI kernel to be loaded above 4G. > + Should be at least kernel 4.3. > **** 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. > @@ -744,6 +748,14 @@ 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 > > @@ -1127,4 +1139,11 @@ The boot loader *must* fill out the following fields in bp, > 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. > diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c > index 2c82bd1..05d77a5 100644 > --- a/arch/x86/boot/compressed/eboot.c > +++ b/arch/x86/boot/compressed/eboot.c > @@ -1394,6 +1394,7 @@ struct boot_params *efi_main(struct efi_config *c, > void *handle; > efi_system_table_t *_table; > bool is64; > + unsigned long loaded_addr; > > efi_early = c; > > @@ -1435,9 +1436,12 @@ struct boot_params *efi_main(struct efi_config *c, > * 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); > @@ -1446,8 +1450,9 @@ struct boot_params *efi_main(struct efi_config *c, > 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); > diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S > index 075bb15..ab52d2c 100644 > --- a/arch/x86/boot/compressed/head_64.S > +++ b/arch/x86/boot/compressed/head_64.S > @@ -266,6 +266,8 @@ 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: > @@ -289,7 +291,10 @@ 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 > > diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S > index 99204e5..09e7c69 100644 > --- a/arch/x86/boot/header.S > +++ b/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 > @@ -478,6 +478,7 @@ pref_address: .quad LOAD_PHYSICAL_ADDR # preferred load 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! Comment is a typo? > > # End of setup header ##################################################### > > diff --git a/arch/x86/include/uapi/asm/bootparam.h b/arch/x86/include/uapi/asm/bootparam.h > index ab456dc..bb9973d 100644 > --- a/arch/x86/include/uapi/asm/bootparam.h > +++ b/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 { > diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c > index d2e00bc..3f9789f 100644 > --- a/arch/x86/kernel/asm-offsets.c > +++ b/arch/x86/kernel/asm-offsets.c > @@ -90,6 +90,7 @@ void common(void) { > OFFSET(BP_init_size, boot_params, hdr.init_size); > 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)); > -- > 1.8.4.5 > > -- > 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/ -Kees -- Kees Cook Chrome OS Security