[PATCH 08/11] kexec-bzImage: Support for loading bzImage using 64bit entry

[Vivek Goyal <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 |  11 ++
 arch/x86/include/asm/kexec.h         |  30 +++++
 arch/x86/kernel/Makefile             |   2 +
 arch/x86/kernel/kexec-bzimage.c      | 234 +++++++++++++++++++++++++++++++++++
 arch/x86/kernel/machine_kexec.c      | 136 ++++++++++++++++++++
 arch/x86/kernel/machine_kexec_64.c   |   3 +-
 6 files changed, 415 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/machine_kexec.c

diff --git a/arch/x86/include/asm/kexec-bzimage.h b/arch/x86/include/asm/kexec-bzimage.h
new file mode 100644
index 0000000..9e83961
--- /dev/null
+++ b/arch/x86/include/asm/kexec-bzimage.h
@@ -0,0 +1,11 @@
+#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_cleanup(struct kimage *image);
+
+#endif  /* _ASM_BZIMAGE_H */
diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
index 17483a4..9bd6fec 100644
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h
@@ -23,6 +23,7 @@
 
 #include <asm/page.h>
 #include <asm/ptrace.h>
+#include <asm/bootparam.h>
 
 /*
  * KEXEC_SOURCE_MEMORY_LIMIT maximum page get_free_page can return.
@@ -161,11 +162,40 @@ 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);
 extern crash_vmclear_fn __rcu *crash_vmclear_loaded_vmcss;
 
+extern int kexec_setup_initrd(struct boot_params *boot_params,
+		unsigned long initrd_load_addr, unsigned long initrd_len);
+extern int kexec_setup_cmdline(struct boot_params *boot_params,
+		unsigned long bootparams_load_addr,
+		unsigned long cmdline_offset, char *cmdline,
+		unsigned long cmdline_len);
+extern int kexec_setup_boot_parameters(struct boot_params *params);
+
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* _ASM_X86_KEXEC_H */
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index cb648c8..fa9981d 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -67,8 +67,10 @@ obj-$(CONFIG_DYNAMIC_FTRACE)	+= ftrace.o
 obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o
 obj-$(CONFIG_FTRACE_SYSCALLS)	+= ftrace.o
 obj-$(CONFIG_X86_TSC)		+= trace_clock.o
+obj-$(CONFIG_KEXEC)		+= machine_kexec.o
 obj-$(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
diff --git a/arch/x86/kernel/kexec-bzimage.c b/arch/x86/kernel/kexec-bzimage.c
new file mode 100644
index 0000000..cbfcd00
--- /dev/null
+++ b/arch/x86/kernel/kexec-bzimage.c
@@ -0,0 +1,234 @@
+#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 {
+	/*
+	 * Temporary buffer to hold bootparams buffer. This should be
+	 * freed once the bootparam segment has been loaded.
+	 */
+	void *bootparams_buf;
+};
+
+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;
+}
+
+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, ret = 0;
+	unsigned long setup_header_size, params_cmdline_sz;
+	struct boot_params *params;
+	unsigned long bootparam_load_addr, kernel_load_addr, initrd_load_addr;
+	unsigned long purgatory_load_addr;
+	unsigned long kernel_bufsz, kernel_memsz, kernel_align;
+	char *kernel_buf;
+	struct bzimage64_data *ldata;
+	struct kexec_entry64_regs regs64;
+	void *stack;
+
+	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);
+
+	/*
+	 * Load purgatory. For 64bit entry point, purgatory  code can be
+	 * anywhere.
+	 */
+	ret = kexec_load_purgatory(image, 0x3000, -1, 1, &purgatory_load_addr);
+	if (ret) {
+		pr_debug("Loading purgatory failed\n");
+		goto out_free_loader_data;
+	}
+
+	pr_debug("Loaded purgatory at 0x%lx\n", purgatory_load_addr);
+
+	/* Load Bootparams and cmdline */
+	params_cmdline_sz = sizeof(struct boot_params) + cmdline_len;
+	params = kzalloc(params_cmdline_sz, 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, params_cmdline_sz,
+			params_cmdline_sz, 16, 0x3000, -1, 1,
+			&bootparam_load_addr);
+	if (ret)
+		goto out_free_params;
+	pr_debug("Loaded boot_param and command line at 0x%lx sz=0x%lx\n",
+			bootparam_load_addr, params_cmdline_sz);
+
+	/* 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, 0x1000000, 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);
+		ret = kexec_setup_initrd(params, initrd_load_addr, initrd_len);
+		if (ret)
+			goto out_free_params;
+	}
+
+	ret = kexec_setup_cmdline(params, bootparam_load_addr,
+			sizeof(struct boot_params), cmdline, cmdline_len);
+	if (ret)
+		goto out_free_params;
+
+	/* bootloader info. Do we need a separate ID for kexec kernel loader? */
+	params->hdr.type_of_loader = 0x0D << 4;
+	params->hdr.loadflags = 0;
+
+	/* Setup purgatory regs for entry */
+	ret = kexec_purgatory_get_set_symbol(image, "entry64_regs", &regs64,
+					sizeof(regs64), 1);
+	if (ret)
+		goto out_free_params;
+
+	regs64.rbx = 0; /* Bootstrap Processor */
+	regs64.rsi = bootparam_load_addr;
+	regs64.rip = kernel_load_addr + 0x200;
+	stack = kexec_purgatory_get_symbol_addr(image, "stack_end");
+	if (IS_ERR(stack)) {
+		pr_debug("Could not find address of symbol stack_end\n");
+		ret = -EINVAL;
+		goto out_free_params;
+	}
+
+	regs64.rsp = (unsigned long)stack;
+	ret = kexec_purgatory_get_set_symbol(image, "entry64_regs", &regs64,
+					sizeof(regs64), 0);
+	if (ret)
+		goto out_free_params;
+
+	ret = kexec_setup_boot_parameters(params);
+	if (ret)
+		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;
+	return ldata;
+
+out_free_params:
+	kfree(params);
+out_free_loader_data:
+	kfree(ldata);
+	return ERR_PTR(ret);
+}
+
+/* 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;
+
+	if (!ldata)
+		return 0;
+
+	kfree(ldata->bootparams_buf);
+	ldata->bootparams_buf = NULL;
+
+	return 0;
+}
+
+#endif /* CONFIG_X86_64 */
diff --git a/arch/x86/kernel/machine_kexec.c b/arch/x86/kernel/machine_kexec.c
new file mode 100644
index 0000000..ac55890
--- /dev/null
+++ b/arch/x86/kernel/machine_kexec.c
@@ -0,0 +1,136 @@
+/*
+ * handle transition of Linux booting another kernel
+ *
+ * Copyright (C) 2014 Red Hat Inc.
+ * Authors:
+ * 	Vivek Goyal <vgoyal@redhat.com>
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2.  See the file COPYING for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <asm/bootparam.h>
+#include <asm/setup.h>
+
+/*
+ * Common code for x86 and x86_64 used for kexec.
+ *
+ * For the time being it compiles only for x86_64 as there are no image
+ * loaders implemented * for x86. This #ifdef can be removed once somebody
+ * decides to write an image loader on CONFIG_X86_32.
+ */
+
+#ifdef CONFIG_X86_64
+
+int kexec_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;
+
+	return 0;
+}
+
+int kexec_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;
+
+	return 0;
+}
+
+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;
+}
+
+int kexec_setup_boot_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));
+
+	return 0;
+}
+
+#endif /* CONFIG_X86_64 */
diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
index 8866c5e..37df7d3 100644
--- a/arch/x86/kernel/machine_kexec_64.c
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -21,10 +21,11 @@
 #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},
+	{"bzImage64", bzImage64_probe, bzImage64_load, bzImage64_cleanup},
 };
 
 static int nr_file_types = sizeof(kexec_file_type)/sizeof(kexec_file_type[0]);
-- 
1.8.4.2


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