-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: