+From vgoyal@redhat.com Wed Nov 20 09:51:43 2013

+From: Vivek Goyal <vgoyal@redhat.com>

+Date: Wed, 20 Nov 2013 12:50:50 -0500

+Subject: [PATCH 5/6] kexec-bzImage: Support for loading bzImage using 64bit entry

+To: linux-kernel@vger.kernel.org, kexec@lists.infradead.org

+Cc: ebiederm@xmission.com, hpa@zytor.com, mjg59@srcf.ucam.org, greg@kroah.com, Vivek Goyal <vgoyal@redhat.com>

+Message-ID: <1384969851-7251-6-git-send-email-vgoyal@redhat.com>

+

+

+This is loader specific code which can load bzImage and set it up for

+64bit entry. This does not take care of 32bit entry or real mode entry

+yet.

+

+Signed-off-by: Vivek Goyal <vgoyal@redhat.com>

+---

+ arch/x86/include/asm/kexec-bzimage.h | 12 +

+ arch/x86/include/asm/kexec.h | 26 ++

+ arch/x86/kernel/Makefile | 2

+ arch/x86/kernel/kexec-bzimage.c | 375 +++++++++++++++++++++++++++++++++++

+ arch/x86/kernel/machine_kexec_64.c | 4

+ arch/x86/kernel/purgatory_entry_64.S | 119 +++++++++++

+ 6 files changed, 537 insertions(+), 1 deletion(-)

+ create mode 100644 arch/x86/include/asm/kexec-bzimage.h

+ create mode 100644 arch/x86/kernel/kexec-bzimage.c

+ create mode 100644 arch/x86/kernel/purgatory_entry_64.S

+

+--- /dev/null

++++ b/arch/x86/include/asm/kexec-bzimage.h

+@@ -0,0 +1,12 @@

++#ifndef _ASM_BZIMAGE_H

++#define _ASM_BZIMAGE_H

++

++extern int bzImage64_probe(const char *buf, unsigned long len);

++extern void *bzImage64_load(struct kimage *image, char *kernel,

++ unsigned long kernel_len, char *initrd,

++ unsigned long initrd_len, char *cmdline,

++ unsigned long cmdline_len);

++extern int bzImage64_prep_entry(struct kimage *image);

++extern int bzImage64_cleanup(struct kimage *image);

++

++#endif /* _ASM_BZIMAGE_H */

+--- a/arch/x86/include/asm/kexec.h

++++ b/arch/x86/include/asm/kexec.h

+@@ -15,6 +15,9 @@

+ # define PAGES_NR 4

+ #endif

+

++#define KEXEC_PURGATORY_PAGE_SIZE 4096

++#define KEXEC_PURGATORY_CODE_MAX_SIZE 2048

++

+ # define KEXEC_CONTROL_CODE_MAX_SIZE 2048

+

+ #ifndef __ASSEMBLY__

+@@ -141,6 +144,9 @@ relocate_kernel(unsigned long indirectio

+ unsigned long page_list,

+ unsigned long start_address,

+ unsigned int preserve_context);

++void purgatory_entry64(void);

++extern unsigned long purgatory_entry64_regs;

++extern struct desc_struct entry64_gdt;

+ #endif

+

+ #define ARCH_HAS_KIMAGE_ARCH

+@@ -161,6 +167,26 @@ struct kimage_arch {

+ pmd_t *pmd;

+ pte_t *pte;

+ };

++

++struct kexec_entry64_regs {

++ uint64_t rax;

++ uint64_t rbx;

++ uint64_t rcx;

++ uint64_t rdx;

++ uint64_t rsi;

++ uint64_t rdi;

++ uint64_t rsp;

++ uint64_t rbp;

++ uint64_t r8;

++ uint64_t r9;

++ uint64_t r10;

++ uint64_t r11;

++ uint64_t r12;

++ uint64_t r13;

++ uint64_t r14;

++ uint64_t r15;

++ uint64_t rip;

++};

+ #endif

+

+ typedef void crash_vmclear_fn(void);

+--- a/arch/x86/kernel/Makefile

++++ b/arch/x86/kernel/Makefile

+@@ -68,6 +68,7 @@ obj-$(CONFIG_FTRACE_SYSCALLS) += ftrace.

+ obj-$(CONFIG_X86_TSC) += trace_clock.o

+ obj-$(CONFIG_KEXEC) += machine_kexec_$(BITS).o

+ obj-$(CONFIG_KEXEC) += relocate_kernel_$(BITS).o crash.o

++obj-$(CONFIG_KEXEC) += kexec-bzimage.o

+ obj-$(CONFIG_CRASH_DUMP) += crash_dump_$(BITS).o

+ obj-y += kprobes/

+ obj-$(CONFIG_MODULES) += module.o

+@@ -122,4 +123,5 @@ ifeq ($(CONFIG_X86_64),y)

+

+ obj-$(CONFIG_PCI_MMCONFIG) += mmconf-fam10h_64.o

+ obj-y += vsmp_64.o

++ obj-$(CONFIG_KEXEC) += purgatory_entry_64.o

+ endif

+--- /dev/null

++++ b/arch/x86/kernel/kexec-bzimage.c

+@@ -0,0 +1,375 @@

++#include <linux/string.h>

++#include <linux/printk.h>

++#include <linux/errno.h>

++#include <linux/slab.h>

++#include <linux/kexec.h>

++#include <linux/kernel.h>

++#include <linux/mm.h>

++

++#include <asm/bootparam.h>

++#include <asm/setup.h>

++

++#ifdef CONFIG_X86_64

++

++struct bzimage64_data {

++ unsigned long kernel_load_addr;

++ unsigned long bootparams_load_addr;

++

++ /*

++ * Temporary buffer to hold bootparams buffer. This should be

++ * freed once the bootparam segment has been loaded.

++ */

++ void *bootparams_buf;

++ struct page *purgatory_page;

++};

++

++int bzImage64_probe(const char *buf, unsigned long len)

++{

++ int ret = -ENOEXEC;

++ struct setup_header *header;

++

++ if (len < 2 * 512) {

++ pr_debug("File is too short to be a bzImage\n");

++ return ret;

++ }

++

++ header = (struct setup_header *)(buf + 0x1F1);

++ if (memcmp((char *)&header->header, "HdrS", 4) != 0) {

++ pr_debug("Not a bzImage\n");

++ return ret;

++ }

++

++ if (header->boot_flag != 0xAA55) {

++ /* No x86 boot sector present */

++ pr_debug("No x86 boot sector present\n");

++ return ret;

++ }

++

++ if (header->version < 0x020C) {

++ /* Must be at least protocol version 2.12 */

++ pr_debug("Must be at least protocol version 2.12\n");

++ return ret;

++ }

++

++ if ((header->loadflags & 1) == 0) {

++ /* Not a bzImage */

++ pr_debug("zImage not a bzImage\n");

++ return ret;

++ }

++

++ if ((header->xloadflags & 3) != 3) {

++ /* XLF_KERNEL_64 and XLF_CAN_BE_LOADED_ABOVE_4G should be set */

++ pr_debug("Not a relocatable bzImage64\n");

++ return ret;

++ }

++

++ /* I've got a bzImage */

++ pr_debug("It's a relocatable bzImage64\n");

++ ret = 0;

++

++ return ret;

++}

++

++static int setup_memory_map_entries(struct boot_params *params)

++{

++ unsigned int nr_e820_entries;

++

++ /* TODO: What about EFI */

++ nr_e820_entries = e820_saved.nr_map;

++ if (nr_e820_entries > E820MAX)

++ nr_e820_entries = E820MAX;

++

++ params->e820_entries = nr_e820_entries;

++ memcpy(&params->e820_map, &e820_saved.map,

++ nr_e820_entries * sizeof(struct e820entry));

++

++ return 0;

++}

++

++static void setup_linux_system_parameters(struct boot_params *params)

++{

++ unsigned int nr_e820_entries;

++ unsigned long long mem_k, start, end;

++ int i;

++

++ /* Get subarch from existing bootparams */

++ params->hdr.hardware_subarch = boot_params.hdr.hardware_subarch;

++

++ /* Copying screen_info will do? */

++ memcpy(&params->screen_info, &boot_params.screen_info,

++ sizeof(struct screen_info));

++

++ /* Fill in memsize later */

++ params->screen_info.ext_mem_k = 0;

++ params->alt_mem_k = 0;

++

++ /* Default APM info */

++ memset(&params->apm_bios_info, 0, sizeof(params->apm_bios_info));

++

++ /* Default drive info */

++ memset(&params->hd0_info, 0, sizeof(params->hd0_info));

++ memset(&params->hd1_info, 0, sizeof(params->hd1_info));

++

++ /* Default sysdesc table */

++ params->sys_desc_table.length = 0;

++

++ setup_memory_map_entries(params);

++ nr_e820_entries = params->e820_entries;

++

++ for(i = 0; i < nr_e820_entries; i++) {

++ if (params->e820_map[i].type != E820_RAM)

++ continue;

++ start = params->e820_map[i].addr;

++ end = params->e820_map[i].addr + params->e820_map[i].size - 1;

++

++ if ((start <= 0x100000) && end > 0x100000) {

++ mem_k = (end >> 10) - (0x100000 >> 10);

++ params->screen_info.ext_mem_k = mem_k;

++ params->alt_mem_k = mem_k;

++ if (mem_k > 0xfc00)

++ params->screen_info.ext_mem_k = 0xfc00; /* 64M*/

++ if (mem_k > 0xffffffff)

++ params->alt_mem_k = 0xffffffff;

++ }

++ }

++

++ /* Setup EDD info */

++ memcpy(params->eddbuf, boot_params.eddbuf,

++ EDDMAXNR * sizeof(struct edd_info));

++ params->eddbuf_entries = boot_params.eddbuf_entries;

++

++ memcpy(params->edd_mbr_sig_buffer, boot_params.edd_mbr_sig_buffer,

++ EDD_MBR_SIG_MAX * sizeof(unsigned int));

++}

++

++static void setup_initrd(struct boot_params *boot_params, unsigned long initrd_load_addr, unsigned long initrd_len)

++{

++ boot_params->hdr.ramdisk_image = initrd_load_addr & 0xffffffffUL;

++ boot_params->hdr.ramdisk_size = initrd_len & 0xffffffffUL;

++

++ boot_params->ext_ramdisk_image = initrd_load_addr >> 32;

++ boot_params->ext_ramdisk_size = initrd_len >> 32;

++}

++

++static void setup_cmdline(struct boot_params *boot_params,

++ unsigned long bootparams_load_addr,

++ unsigned long cmdline_offset, char *cmdline,

++ unsigned long cmdline_len)

++{

++ char *cmdline_ptr = ((char *)boot_params) + cmdline_offset;

++ unsigned long cmdline_ptr_phys;

++ uint32_t cmdline_low_32, cmdline_ext_32;

++

++ memcpy(cmdline_ptr, cmdline, cmdline_len);

++ cmdline_ptr[cmdline_len - 1] = '\0';

++

++ cmdline_ptr_phys = bootparams_load_addr + cmdline_offset;

++ cmdline_low_32 = cmdline_ptr_phys & 0xffffffffUL;

++ cmdline_ext_32 = cmdline_ptr_phys >> 32;

++

++ boot_params->hdr.cmd_line_ptr = cmdline_low_32;

++ if (cmdline_ext_32)

++ boot_params->ext_cmd_line_ptr = cmdline_ext_32;

++}

++

++void *bzImage64_load(struct kimage *image, char *kernel,

++ unsigned long kernel_len,

++ char *initrd, unsigned long initrd_len,

++ char *cmdline, unsigned long cmdline_len)

++{

++

++ struct setup_header *header;

++ int setup_sects, kern16_size_needed, kern16_size, ret = 0;

++ unsigned long setup_size, setup_header_size;

++ struct boot_params *params;

++ unsigned long bootparam_load_addr, kernel_load_addr, initrd_load_addr;

++ unsigned long kernel_bufsz, kernel_memsz, kernel_align;

++ char *kernel_buf;

++ struct bzimage64_data *ldata;

++

++ header = (struct setup_header *)(kernel + 0x1F1);

++ setup_sects = header->setup_sects;

++ if (setup_sects == 0)

++ setup_sects = 4;

++

++ kern16_size = (setup_sects + 1) * 512;

++ if (kernel_len < kern16_size) {

++ pr_debug("bzImage truncated\n");

++ return ERR_PTR(-ENOEXEC);

++ }

++

++ if (cmdline_len > header->cmdline_size) {

++ pr_debug("Kernel command line too long\n");

++ return ERR_PTR(-EINVAL);

++ }

++

++ /* Allocate loader specific data */

++ ldata = kzalloc(sizeof(struct bzimage64_data), GFP_KERNEL);

++ if (!ldata)

++ return ERR_PTR(-ENOMEM);

++

++ /* Argument/parameter segment */

++ kern16_size_needed = kern16_size;

++ if (kern16_size_needed < 4096)

++ kern16_size_needed = 4096;

++

++ setup_size = kern16_size_needed + cmdline_len;

++ params = kzalloc(setup_size, GFP_KERNEL);

++ if (!params) {

++ ret = -ENOMEM;

++ goto out_free_loader_data;

++ }

++

++ /* Copy setup header onto bootparams. */

++ setup_header_size = 0x0202 + kernel[0x0201] - 0x1F1;

++

++ /* Is there a limit on setup header size? */

++ memcpy(&params->hdr, (kernel + 0x1F1), setup_header_size);

++ ret = kexec_add_buffer(image, (char *)params, setup_size,

++ setup_size, 16, 0x3000, -1, 1, &bootparam_load_addr);

++ if (ret)

++ goto out_free_params;

++ pr_debug("Loaded boot_param and command line at 0x%lx\n",

++ bootparam_load_addr);

++

++ /* Load kernel */

++ kernel_buf = kernel + kern16_size;

++ kernel_bufsz = kernel_len - kern16_size;

++ kernel_memsz = ALIGN(header->init_size, 4096);

++ kernel_align = header->kernel_alignment;

++

++ ret = kexec_add_buffer(image, kernel_buf,

++ kernel_bufsz, kernel_memsz, kernel_align, 0x100000,

++ -1, 1, &kernel_load_addr);

++ if (ret)

++ goto out_free_params;

++

++ pr_debug("Loaded 64bit kernel at 0x%lx sz = 0x%lx\n", kernel_load_addr,

++ kernel_memsz);

++

++ /* Load initrd high */

++ if (initrd) {

++ ret = kexec_add_buffer(image, initrd, initrd_len, initrd_len,

++ 4096, 0x10000000, ULONG_MAX, 1, &initrd_load_addr);

++ if (ret)

++ goto out_free_params;

++

++ pr_debug("Loaded initrd at 0x%lx sz = 0x%lx\n",

++ initrd_load_addr, initrd_len);

++ setup_initrd(params, initrd_load_addr, initrd_len);

++ }

++

++ setup_cmdline(params, bootparam_load_addr, kern16_size_needed,

++ cmdline, cmdline_len);

++

++ /* bootloader info. Do we need a separate ID for kexec kernel loader? */

++ params->hdr.type_of_loader = 0x0D << 4;

++ params->hdr.loadflags = 0;

++

++ setup_linux_system_parameters(params);

++

++ /*

++ * Allocate a purgatory page. For 64bit entry point, purgatory

++ * code can be anywhere.

++ *

++ * Control page allocation logic goes through segment list to

++ * make sure allocated page is not destination page. So allocate

++ * control page after all required segment have been prepared.

++ */

++ ldata->purgatory_page = kimage_alloc_control_pages(image,

++ get_order(KEXEC_PURGATORY_PAGE_SIZE));

++

++ if (!ldata->purgatory_page) {

++ printk(KERN_ERR "Could not allocate purgatory page\n");

++ ret = -ENOMEM;

++ goto out_free_params;

++ }

++

++ /*

++ * Store pointer to params so that it could be freed after loading

++ * params segment has been loaded and contents have been copied

++ * somewhere else.

++ */

++ ldata->bootparams_buf = params;

++ ldata->kernel_load_addr = kernel_load_addr;

++ ldata->bootparams_load_addr = bootparam_load_addr;

++ return ldata;

++

++out_free_params:

++ kfree(params);

++out_free_loader_data:

++ kfree(ldata);

++ return ERR_PTR(ret);

++}

++

++int bzImage64_prep_entry(struct kimage *image)

++{

++ struct bzimage64_data *ldata;

++ char *purgatory_page;

++ unsigned long regs_offset, gdt_offset, purgatory_page_phys;

++ struct kexec_entry64_regs *regs;

++ char *gdt_ptr;

++ unsigned long long *gdt_addr;

++

++ if (!image->file_mode)

++ return 0;

++

++ ldata = image->image_loader_data;

++ if (!ldata)

++ return -EINVAL;

++

++ /* Copy purgatory code to its control page */

++ purgatory_page = page_address(ldata->purgatory_page);

++

++ /* Physical address of purgatory page */

++ purgatory_page_phys = PFN_PHYS(page_to_pfn(ldata->purgatory_page));

++

++ memcpy(purgatory_page, purgatory_entry64,

++ KEXEC_PURGATORY_CODE_MAX_SIZE);

++

++ /* Set registers appropriately */

++ regs_offset = (unsigned long)&purgatory_entry64_regs -

++ (unsigned long)purgatory_entry64;

++ regs = (struct kexec_entry64_regs *) (purgatory_page + regs_offset);

++

++ regs->rbx = 0; /* Bootstrap Processor */

++ regs->rsi = ldata->bootparams_load_addr;

++ regs->rip = ldata->kernel_load_addr + 0x200;

++

++ /* Fix up gdt */

++ gdt_offset = (unsigned long)&entry64_gdt -

++ (unsigned long)purgatory_entry64;

++

++ gdt_ptr = purgatory_page + gdt_offset;

++

++ /* Skip a word which contains size of gdt table */

++ gdt_addr = (unsigned long long *)(gdt_ptr + 2);

++

++ *gdt_addr = (unsigned long long)gdt_ptr;

++

++ /*

++ * Update the relocated address of gdt. By the time we load gdt

++ * in purgatory, we are running using identity mapped tables.

++ * Load identity mapped address here.

++ */

++ *gdt_addr = (unsigned long long)(purgatory_page_phys + gdt_offset);

++

++ /*

++ * Jump to purgatory after control page. By the time we jump to

++ * purgatory, we are using itentifiy mapped page tables

++ */

++ kimage_set_start_addr(image, purgatory_page_phys);

++ return 0;

++}

++

++/* This cleanup function is called after various segments have been loaded */

++int bzImage64_cleanup(struct kimage *image)

++{

++ struct bzimage64_data *ldata = image->image_loader_data;

++

++ kfree(ldata->bootparams_buf);

++ ldata->bootparams_buf = NULL;

++ return 0;

++}

++

++#endif /* CONFIG_X86_64 */

+--- a/arch/x86/kernel/machine_kexec_64.c

++++ b/arch/x86/kernel/machine_kexec_64.c

+@@ -21,10 +21,12 @@

+ #include <asm/tlbflush.h>

+ #include <asm/mmu_context.h>

+ #include <asm/debugreg.h>

++#include <asm/kexec-bzimage.h>

+

+ /* arch dependent functionality related to kexec file based syscall */

+ static struct kexec_file_type kexec_file_type[]={

+- {"", NULL, NULL, NULL, NULL},

++ {"bzImage64", bzImage64_probe, bzImage64_load, bzImage64_prep_entry,

++ bzImage64_cleanup},

+ };

+

+ static int nr_file_types = sizeof(kexec_file_type)/sizeof(kexec_file_type[0]);

+--- /dev/null

++++ b/arch/x86/kernel/purgatory_entry_64.S

+@@ -0,0 +1,119 @@

++/*

++ * Copyright (C) 2013 Red Hat Inc.

++ *

++ * Author(s): Vivek Goyal <vgoyal@redhat.com>

++ *

++ * This program is free software; you can redistribute it and/or modify

++ * it under the terms of the GNU General Public License as published by

++ * the Free Software Foundation (version 2 of the License).

++ *

++ * This program is distributed in the hope that it will be useful,

++ * but WITHOUT ANY WARRANTY; without even the implied warranty of

++ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

++ * GNU General Public License for more details.

++ *

++ * You should have received a copy of the GNU General Public License

++ * along with this program; if not, write to the Free Software

++ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

++ */

++

++

++/*

++ * One page for purgatory. Code occupies first KEXEC_PURGATORY_CODE_MAX_SIZE

++ * bytes. Rest is for data/stack etc.

++ */

++#include <asm/page.h>

++

++ .text

++ .align PAGE_SIZE

++ .code64

++ .globl purgatory_entry64, purgatory_entry64_regs, entry64_gdt

++

++

++purgatory_entry64:

++ /* Setup a gdt that should be preserved */

++ lgdt entry64_gdt(%rip)

++

++ /* load the data segments */

++ movl $0x18, %eax /* data segment */

++ movl %eax, %ds

++ movl %eax, %es

++ movl %eax, %ss

++ movl %eax, %fs

++ movl %eax, %gs

++

++ /* Setup new stack */

++ leaq stack_init(%rip), %rsp

++ pushq $0x10 /* CS */

++ leaq new_cs_exit(%rip), %rax

++ pushq %rax

++ lretq

++new_cs_exit:

++

++ /*

++ * Load the registers except rsp. rsp is already loaded with stack

++ * at the end of this page

++ */

++ movq rax(%rip), %rax

++ movq rbx(%rip), %rbx

++ movq rcx(%rip), %rcx

++ movq rdx(%rip), %rdx

++ movq rsi(%rip), %rsi

++ movq rdi(%rip), %rdi

++ movq rbp(%rip), %rbp

++ movq r8(%rip), %r8

++ movq r9(%rip), %r9

++ movq r10(%rip), %r10

++ movq r11(%rip), %r11

++ movq r12(%rip), %r12

++ movq r13(%rip), %r13

++ movq r14(%rip), %r14

++ movq r15(%rip), %r15

++

++ /* Jump to the new code... */

++ jmpq *rip(%rip)

++

++ .balign 16

++purgatory_entry64_regs:

++rax: .quad 0x00000000

++rbx: .quad 0x00000000

++rcx: .quad 0x00000000

++rdx: .quad 0x00000000

++rsi: .quad 0x00000000

++rdi: .quad 0x00000000

++rsp: .quad 0x00000000

++rbp: .quad 0x00000000

++r8: .quad 0x00000000

++r9: .quad 0x00000000

++r10: .quad 0x00000000

++r11: .quad 0x00000000

++r12: .quad 0x00000000

++r13: .quad 0x00000000

++r14: .quad 0x00000000

++r15: .quad 0x00000000

++rip: .quad 0x00000000

++

++ /* GDT */

++ .balign 16

++entry64_gdt:

++ /* 0x00 unusable segment

++ * 0x08 unused

++ * so use them as gdt ptr

++ */

++ .word gdt_end - entry64_gdt - 1

++ .quad entry64_gdt

++ .word 0, 0, 0

++

++ /* 0x10 4GB flat code segment */

++ .word 0xFFFF, 0x0000, 0x9A00, 0x00AF

++

++ /* 0x18 4GB flat data segment */

++ .word 0xFFFF, 0x0000, 0x9200, 0x00CF

++gdt_end:

++

++ .globl kexec_purgatory_code_size

++.set kexec_purgatory_code_size, . - purgatory_entry64

++

++/* Fill rest of the page with zeros to be used as stack */

++stack: .fill purgatory_entry64 + PAGE_SIZE - ., 1, 0

++stack_init: