To support memory backup/restore an option named
--load-preserve-context is added to kexec. When it is specified
toggether with --mem-max, most segments for crash dump support are
loaded, and the memory range between mem_min to mem_max which has no
segments loaded are loaded as backup segments. To support jump back
from kexeced, options named --load-jump-back-helper and --entry are
added to load a helper image with specified entry to jump back.
Signed-off-by: Huang Ying <ying.huang at intel.com>
---
kexec/arch/i386/crashdump-x86.c | 51 +++++++---
kexec/arch/i386/kexec-bzImage.c | 10 +-
kexec/arch/i386/kexec-elf-x86.c | 4
kexec/arch/i386/kexec-x86-common.c | 3
kexec/arch/i386/x86-linux-setup.h | 3
kexec/crashdump-elf.c | 2
kexec/crashdump.c | 1
kexec/kexec-syscall.h | 5 -
kexec/kexec.c | 177 +++++++++++++++++++++++++++++++++++-
kexec/kexec.h | 12 ++
purgatory/arch/i386/purgatory-x86.c | 14 ++
purgatory/arch/i386/setup-x86.S | 3
purgatory/include/purgatory.h | 1
purgatory/printf.c | 38 ++++++-
14 files changed, 291 insertions(+), 33 deletions(-)
--- a/kexec/kexec-syscall.h
+++ b/kexec/kexec-syscall.h
@@ -75,8 +75,9 @@ static inline long kexec_reboot(void)
}
-#define KEXEC_ON_CRASH 0x00000001
-#define KEXEC_ARCH_MASK 0xffff0000
+#define KEXEC_ON_CRASH 0x00000001
+#define KEXEC_PRESERVE_CONTEXT 0x00000002
+#define KEXEC_ARCH_MASK 0xffff0000
/* These values match the ELF architecture values.
* Unless there is a good reason that should continue to be the case.
--- a/kexec/kexec.c
+++ b/kexec/kexec.c
@@ -378,6 +378,91 @@ unsigned long add_buffer_virt(struct kex
buf_min, buf_max, buf_end, 0);
}
+static int find_memory_range(struct kexec_info *info,
+ unsigned long *base, unsigned long *size)
+{
+ int i;
+ unsigned long start, end;
+
+ for (i = 0; i < info->memory_ranges; i++) {
+ if (info->memory_range[i].type != RANGE_RAM)
+ continue;
+ start = info->memory_range[i].start;
+ end = info->memory_range[i].end;
+ if (end > *base && start < *base + *size) {
+ if (start > *base) {
+ *size = *base + *size - start;
+ *base = start;
+ }
+ if (end < *base + *size)
+ *size = end - *base;
+ return 1;
+ }
+ }
+ return 0;
+}
+
+static int find_segment_hole(struct kexec_info *info,
+ unsigned long *base, unsigned long *size)
+{
+ int i;
+ unsigned long seg_base, seg_size;
+
+ for (i = 0; i < info->nr_segments; i++) {
+ seg_base = (unsigned long)info->segment[i].mem;
+ seg_size = info->segment[i].memsz;
+
+ if (seg_base + seg_size <= *base)
+ continue;
+ else if (seg_base >= *base + *size)
+ break;
+ else if (*base < seg_base) {
+ *size = seg_base - *base;
+ break;
+ } else if (seg_base + seg_size < *base + *size) {
+ *size = *base + *size - (seg_base + seg_size);
+ *base = seg_base + seg_size;
+ } else {
+ *size = 0;
+ break;
+ }
+ }
+ return *size;
+}
+
+int add_backup_segments(struct kexec_info *info, unsigned long backup_base,
+ unsigned long backup_size)
+{
+ unsigned long mem_base, mem_size, bkseg_base, bkseg_size, start, end;
+ unsigned long pagesize;
+
+ pagesize = getpagesize();
+ while (backup_size) {
+ mem_base = backup_base;
+ mem_size = backup_size;
+ if (!find_memory_range(info, &mem_base, &mem_size))
+ break;
+ backup_size = backup_base + backup_size - \
+ (mem_base + mem_size);
+ backup_base = mem_base + mem_size;
+ while (mem_size) {
+ bkseg_base = mem_base;
+ bkseg_size = mem_size;
+ if (sort_segments(info) < 0)
+ return -1;
+ if (!find_segment_hole(info, &bkseg_base, &bkseg_size))
+ break;
+ start = (bkseg_base + pagesize - 1) & ~(pagesize - 1);
+ end = (bkseg_base + bkseg_size) & ~(pagesize - 1);
+ add_segment(info, NULL, 0, start, end-start);
+ mem_size = mem_base + mem_size - \
+ (bkseg_base + bkseg_size);
+ mem_base = bkseg_base + bkseg_size;
+ }
+ }
+ return 0;
+}
+
char *slurp_file(const char *filename, off_t *r_size)
{
int fd;
@@ -581,7 +666,7 @@ static void update_purgatory(struct kexe
* Load the new kernel
*/
static int my_load(const char *type, int fileind, int argc, char **argv,
- unsigned long kexec_flags)
+ unsigned long kexec_flags, unsigned long entry)
{
char *kernel;
char *kernel_buf;
@@ -665,6 +750,9 @@ static int my_load(const char *type, int
if (arch_compat_trampoline(&info) < 0) {
return -1;
}
+ if (info.kexec_flags & KEXEC_PRESERVE_CONTEXT) {
+ add_backup_segments(&info, mem_min, mem_max - mem_min + 1);
+ }
/* Verify all of the segments load to a valid location in memory */
for (i = 0; i < info.nr_segments; i++) {
if (!valid_memory_segment(&info, info.segment +i)) {
@@ -681,6 +769,8 @@ static int my_load(const char *type, int
}
/* if purgatory is loaded update it */
update_purgatory(&info);
+ if (entry)
+ info.entry = entry;
#if 0
fprintf(stderr, "kexec_load: entry = %p flags = %lx\n",
info.entry, info.kexec_flags);
@@ -754,6 +844,47 @@ static int my_exec(void)
return -1;
}
+static int kexec_loaded(void);
+
+static int load_jump_back_helper_image(unsigned long kexec_flags,
+ unsigned long entry)
+{
+ int result;
+ struct kexec_segment seg;
+
+ memset(&seg, 0, sizeof(seg));
+ result = kexec_load((void *)entry, 1, &seg,
+ kexec_flags);
+ return result;
+}
+
+/*
+ * Jump back to the original kernel
+ */
+static int my_load_jump_back_helper(unsigned long kexec_flags,
+ unsigned long entry)
+{
+ int result;
+
+ if (kexec_loaded()) {
+ fprintf(stderr, "There is kexec kernel loaded, make sure "
+ "you are in kexeced kernel.\n");
+ return -1;
+ }
+ if (!entry) {
+ fprintf(stderr, "Please specify jump back entry "
+ "in command line\n");
+ return -1;
+ }
+ result = load_jump_back_helper_image(kexec_flags, entry);
+ if (result) {
+ fprintf(stderr, "load jump back kernel failed: %s\n",
+ strerror(errno));
+ return result;
+ }
+ return result;
+}
+
static void version(void)
{
printf(PACKAGE_STRING " released " PACKAGE_DATE "\n");
@@ -787,6 +918,10 @@ void usage(void)
" --mem-max=<addr> Specify the highest memory address to\n"
" load code into.\n"
" --reuseinird Reuse initrd from first boot.\n"
+ " --load-preserve-context Load the new kernel and preserve\n"
+ " context of current kernel during kexec.\n"
+ " --load-jump-back-helper Load a helper image to jump back\n"
+ " to original kernel.\n"
"\n"
"Supported kernel file types and options: \n");
for (i = 0; i < file_types; i++) {
@@ -895,11 +1030,13 @@ int main(int argc, char *argv[])
{
int do_load = 1;
int do_exec = 0;
+ int do_load_jump_back_helper = 0;
int do_shutdown = 1;
int do_sync = 1;
int do_ifdown = 0;
int do_unload = 0;
int do_reuse_initrd = 0;
+ unsigned long entry = 0;
char *type = 0;
char *endptr;
int opt;
@@ -949,6 +1086,32 @@ int main(int argc, char *argv[])
do_ifdown = 1;
do_exec = 1;
break;
+ case OPT_LOAD_JUMP_BACK_HELPER:
+ do_load = 0;
+ do_shutdown = 0;
+ do_sync = 1;
+ do_ifdown = 1;
+ do_exec = 0;
+ do_load_jump_back_helper = 1;
+ kexec_flags = KEXEC_PRESERVE_CONTEXT;
+ break;
+ case OPT_ENTRY:
+ entry = strtoul(optarg, &endptr, 0);
+ if (*endptr) {
+ fprintf(stderr,
+ "Bad option value in --load-jump-back-helper=%s\n",
+ optarg);
+ usage();
+ return 1;
+ }
+ break;
+ case OPT_LOAD_PRESERVE_CONTEXT:
+ do_load = 1;
+ do_exec = 0;
+ do_shutdown = 0;
+ do_sync = 1;
+ kexec_flags = KEXEC_PRESERVE_CONTEXT;
+ break;
case OPT_TYPE:
type = optarg;
break;
@@ -994,6 +1157,13 @@ int main(int argc, char *argv[])
die("Then try loading kdump kernel\n");
}
+ if (do_load && (kexec_flags & KEXEC_PRESERVE_CONTEXT) &&
+ mem_max == ULONG_MAX) {
+ printf("Please specify memory range used by kexeced kernel\n");
+ printf("to preserve the context of original kernel with \n");
+ die("\"--mem-max\" parameter\n");
+ }
+
fileind = optind;
/* Reset getopt for the next pass; called in other source modules */
opterr = 1;
@@ -1021,7 +1191,7 @@ int main(int argc, char *argv[])
result = k_unload(kexec_flags);
}
if (do_load && (result == 0)) {
- result = my_load(type, fileind, argc, argv, kexec_flags);
+ result = my_load(type, fileind, argc, argv, kexec_flags, entry);
}
/* Don't shutdown unless there is something to reboot to! */
if ((result == 0) && (do_shutdown || do_exec) && !kexec_loaded()) {
@@ -1039,6 +1209,9 @@ int main(int argc, char *argv[])
if ((result == 0) && do_exec) {
result = my_exec();
}
+ if ((result == 0) && do_load_jump_back_helper) {
+ result = my_load_jump_back_helper(kexec_flags, entry);
+ }
fflush(stdout);
fflush(stderr);
--- a/kexec/kexec.h
+++ b/kexec/kexec.h
@@ -174,7 +174,10 @@ extern int file_types;
#define OPT_MEM_MIN 256
#define OPT_MEM_MAX 257
#define OPT_REUSE_INITRD 258
-#define OPT_MAX 259
+#define OPT_LOAD_PRESERVE_CONTEXT 259
+#define OPT_LOAD_JUMP_BACK_HELPER 260
+#define OPT_ENTRY 261
+#define OPT_MAX 262
#define KEXEC_OPTIONS \
{ "help", 0, 0, OPT_HELP }, \
{ "version", 0, 0, OPT_VERSION }, \
@@ -183,6 +186,9 @@ extern int file_types;
{ "load", 0, 0, OPT_LOAD }, \
{ "unload", 0, 0, OPT_UNLOAD }, \
{ "exec", 0, 0, OPT_EXEC }, \
+ { "load-preserve-context", 0, 0, OPT_LOAD_PRESERVE_CONTEXT}, \
+ { "load-jump-back-helper", 0, 0, OPT_LOAD_JUMP_BACK_HELPER }, \
+ { "entry", 1, 0, OPT_ENTRY }, \
{ "type", 1, 0, OPT_TYPE }, \
{ "load-panic", 0, 0, OPT_PANIC }, \
{ "mem-min", 1, 0, OPT_MEM_MIN }, \
@@ -242,6 +248,10 @@ int kexec_iomem_for_each_line(char *matc
int parse_iomem_single(char *str, uint64_t *start, uint64_t *end);
const char * proc_iomem(void);
+extern int add_backup_segments(struct kexec_info *info,
+ unsigned long backup_base,
+ unsigned long backup_size);
+
#define MAX_LINE 160
#ifdef DEBUG
--- a/kexec/arch/i386/kexec-bzImage.c
+++ b/kexec/arch/i386/kexec-bzImage.c
@@ -114,6 +114,7 @@ int do_bzImage_load(struct kexec_info *i
unsigned int relocatable_kernel = 0;
unsigned long kernel32_load_addr;
char *modified_cmdline;
+ unsigned long cmdline_end;
/*
* Find out about the file I am about to load.
@@ -166,7 +167,7 @@ int do_bzImage_load(struct kexec_info *i
/* Need to append some command line parameters internally in case of
* taking crash dumps.
*/
- if (info->kexec_flags & KEXEC_ON_CRASH) {
+ if (info->kexec_flags & (KEXEC_ON_CRASH | KEXEC_PRESERVE_CONTEXT)) {
modified_cmdline = xmalloc(COMMAND_LINE_SIZE);
memset((void *)modified_cmdline, 0, COMMAND_LINE_SIZE);
if (command_line) {
@@ -205,11 +206,11 @@ int do_bzImage_load(struct kexec_info *i
0x3000, 640*1024, -1, 0);
dbgprintf("Loaded purgatory at addr 0x%lx\n", info->rhdr.rel_addr);
/* The argument/parameter segment */
- setup_size = kern16_size + command_line_len;
+ setup_size = kern16_size + command_line_len + PURGATORY_CMDLINE_SIZE;
real_mode = xmalloc(setup_size);
memcpy(real_mode, kernel, kern16_size);
- if (info->kexec_flags & KEXEC_ON_CRASH) {
+ if (info->kexec_flags & (KEXEC_ON_CRASH | KEXEC_PRESERVE_CONTEXT)) {
/* If using bzImage for capture kernel, then we will not be
* executing real mode code. setup segment can be loaded
* anywhere as we will be just reading command line.
@@ -316,6 +317,9 @@ int do_bzImage_load(struct kexec_info *i
elf_rel_set_symbol(&info->rhdr, "entry16_regs", ®s16, sizeof(regs16));
elf_rel_set_symbol(&info->rhdr, "entry16_debug_regs", ®s16, sizeof(regs16));
elf_rel_set_symbol(&info->rhdr, "entry32_regs", ®s32, sizeof(regs32));
+ cmdline_end = setup_base + kern16_size + command_line_len - 1;
+ elf_rel_set_symbol(&info->rhdr, "cmdline_end", &cmdline_end,
+ sizeof(unsigned long));
/* Fill in the information BIOS calls would normally provide. */
if (!real_mode_entry) {
--- a/kexec/arch/i386/x86-linux-setup.h
+++ b/kexec/arch/i386/x86-linux-setup.h
@@ -15,4 +15,7 @@ void setup_linux_system_parameters(struc
#define KERN32_BASE 0x100000 /* 1MB */
#define INITRD_BASE 0x1000000 /* 16MB */
+/* command line parameter may be appended by purgatory */
+#define PURGATORY_CMDLINE_SIZE 64
+
#endif /* X86_LINUX_SETUP_H */
--- a/purgatory/arch/i386/purgatory-x86.c
+++ b/purgatory/arch/i386/purgatory-x86.c
@@ -31,6 +31,8 @@ uint8_t reset_vga = 0;
uint8_t legacy_timer = 0;
uint8_t legacy_pic = 0;
uint8_t panic_kernel = 0;
+unsigned long jump_back_entry = 0;
+char *cmdline_end = 0;
void setup_arch(void)
{
@@ -40,8 +42,18 @@ void setup_arch(void)
/* if (legacy_timer) x86_setup_legacy_timer(); */
}
+extern void x86_setup_jump_back_entry();
+
/* This function can be used to execute after the SHA256 verification. */
void post_verification_setup_arch(void)
{
- if (panic_kernel) crashdump_backup_memory();
+ if (panic_kernel) crashdump_backup_memory();
+ if (jump_back_entry) x86_setup_jump_back_entry();
+}
+
+void x86_setup_jump_back_entry()
+{
+ if (cmdline_end)
+ sprintf(cmdline_end, " kexec_jump_back_entry=0x%x",
+ jump_back_entry);
}
--- a/purgatory/arch/i386/setup-x86.S
+++ b/purgatory/arch/i386/setup-x86.S
@@ -41,6 +41,9 @@ purgatory_start:
ljmp $0x10,$1f
1:
+ movl 0(%esp), %eax
+ movl %eax, jump_back_entry
+
/* Setup a stack */
movl $lstack_end, %esp
--- a/purgatory/printf.c
+++ b/purgatory/printf.c
@@ -33,19 +33,23 @@ PRINTF and friends
%s - string
Note: width specification not supported
**************************************************************************/
-void printf(const char *fmt, ...)
+void vsprintf(char *buffer, const char *fmt, va_list args)
{
- va_list args;
char *p;
- va_start(args, fmt);
for ( ; *fmt != '\0'; ++fmt) {
if (*fmt != '%') {
- putchar(*fmt);
+ if (buffer)
+ *buffer++ = *fmt;
+ else
+ putchar(*fmt);
continue;
}
if (*++fmt == 's') {
for(p = va_arg(args, char *); *p != '\0'; p++)
- putchar(*p);
+ if (buffer)
+ *buffer++ = *p;
+ else
+ putchar(*p);
}
else { /* Length of item is bounded */
char tmp[40], *q = tmp;
@@ -121,8 +125,30 @@ void printf(const char *fmt, ...)
*q++ = *fmt;
/* now output the saved string */
for (p = tmp; p < q; ++p)
- putchar(*p);
+ if (buffer)
+ *buffer++ = *p;
+ else
+ putchar(*p);
}
}
+ if (buffer)
+ *buffer = '\0';
+}
+
+void sprintf(char *buffer, const char *fmt, ...)
+{
+ va_list args;
+
+ va_start(args, fmt);
+ vsprintf(buffer, fmt, args);
+ va_end(args);
+}
+
+void printf(const char *fmt, ...)
+{
+ va_list args;
+
+ va_start(args, fmt);
+ vsprintf(0, fmt, args);
va_end(args);
}
--- a/purgatory/include/purgatory.h
+++ b/purgatory/include/purgatory.h
@@ -2,6 +2,7 @@
#define PURGATORY_H
void putchar(int ch);
+void sprintf(char *buffer, const char *fmt, ...);
void printf(const char *fmt, ...);
void setup_arch(void);
void post_verification_setup_arch(void);
--- a/kexec/arch/i386/crashdump-x86.c
+++ b/kexec/arch/i386/crashdump-x86.c
@@ -57,7 +57,8 @@ static struct memory_range crash_reserve
* to look into down the line. May be something like /proc/kernelmem or may
* be zone data structures exported from kernel.
*/
-static int get_crash_memory_ranges(struct memory_range **range, int *ranges)
+static int get_crash_memory_ranges(struct memory_range **range, int *ranges,
+ int kexec_flags)
{
const char *iomem = proc_iomem();
int memory_ranges = 0;
@@ -74,10 +75,12 @@ static int get_crash_memory_ranges(struc
/* First entry is for first 640K region. Different bios report first
* 640K in different manner hence hardcoding it */
- crash_memory_range[0].start = 0x00000000;
- crash_memory_range[0].end = 0x0009ffff;
- crash_memory_range[0].type = RANGE_RAM;
- memory_ranges++;
+ if (!(kexec_flags & KEXEC_PRESERVE_CONTEXT)) {
+ crash_memory_range[0].start = 0x00000000;
+ crash_memory_range[0].end = 0x0009ffff;
+ crash_memory_range[0].type = RANGE_RAM;
+ memory_ranges++;
+ }
while(fgets(line, sizeof(line), fp) != 0) {
char *str;
@@ -128,6 +131,22 @@ static int get_crash_memory_ranges(struc
}
}
fclose(fp);
+ if (kexec_flags & KEXEC_PRESERVE_CONTEXT) {
+ int i;
+ for (i = 0; i < memory_ranges; i++) {
+ if (crash_memory_range[i].end > 0x0009ffff) {
+ crash_reserved_mem.start = \
+ crash_memory_range[i].start;
+ break;
+ }
+ }
+ if (crash_reserved_mem.start >= mem_max) {
+ fprintf("Too small mem_max: 0x%lx.\n", mem_max);
+ return -1;
+ }
+ crash_reserved_mem.end = mem_max;
+ crash_reserved_mem.type = RANGE_RAM;
+ }
if (exclude_crash_reserve_region(&memory_ranges) < 0)
return -1;
*range = crash_memory_range;
@@ -514,7 +533,8 @@ int load_crashdump_segments(struct kexec
int nr_ranges, align = 1024;
struct memory_range *mem_range, *memmap_p;
- if (get_crash_memory_ranges(&mem_range, &nr_ranges) < 0)
+ if (get_crash_memory_ranges(&mem_range, &nr_ranges,
+ info->kexec_flags) < 0)
return -1;
/*
@@ -535,14 +555,17 @@ int load_crashdump_segments(struct kexec
add_memmap(memmap_p, crash_reserved_mem.start, sz);
/* Create a backup region segment to store backup data*/
- sz = (BACKUP_SRC_SIZE + align - 1) & ~(align - 1);
- tmp = xmalloc(sz);
- memset(tmp, 0, sz);
- info->backup_start = add_buffer(info, tmp, sz, sz, align,
- 0, max_addr, -1);
- dbgprintf("Created backup segment at 0x%lx\n", info->backup_start);
- if (delete_memmap(memmap_p, info->backup_start, sz) < 0)
- return -1;
+ if (!(info->kexec_flags & KEXEC_PRESERVE_CONTEXT)) {
+ sz = (BACKUP_SRC_SIZE + align - 1) & ~(align - 1);
+ tmp = xmalloc(sz);
+ memset(tmp, 0, sz);
+ info->backup_start = add_buffer(info, tmp, sz, sz, align,
+ 0, max_addr, -1);
+ dbgprintf("Created backup segment at 0x%lx\n",
+ info->backup_start);
+ if (delete_memmap(memmap_p, info->backup_start, sz) < 0)
+ return -1;
+ }
/* Create elf header segment and store crash image data. */
if (arch_options.core_header_type == CORE_TYPE_ELF64) {
--- a/kexec/crashdump-elf.c
+++ b/kexec/crashdump-elf.c
@@ -164,7 +164,7 @@ int FUNC(struct kexec_info *info,
dbgprintf_phdr("Elf header", phdr);
}
- if (has_vmcoreinfo) {
+ if (has_vmcoreinfo && !(info->kexec_flags & KEXEC_PRESERVE_CONTEXT)) {
phdr = (PHDR *) bufp;
bufp += sizeof(PHDR);
phdr->p_type = PT_NOTE;
--- a/kexec/arch/i386/kexec-elf-x86.c
+++ b/kexec/arch/i386/kexec-elf-x86.c
@@ -170,7 +170,7 @@ int elf_x86_load(int argc, char **argv,
/* Need to append some command line parameters internally in case of
* taking crash dumps.
*/
- if (info->kexec_flags & KEXEC_ON_CRASH) {
+ if (info->kexec_flags & (KEXEC_ON_CRASH|KEXEC_PRESERVE_CONTEXT)) {
modified_cmdline = xmalloc(COMMAND_LINE_SIZE);
memset((void *)modified_cmdline, 0, COMMAND_LINE_SIZE);
if (command_line) {
@@ -257,7 +257,7 @@ int elf_x86_load(int argc, char **argv,
/* If panic kernel is being loaded, additional segments need
* to be created. */
- if (info->kexec_flags & KEXEC_ON_CRASH) {
+ if (info->kexec_flags & (KEXEC_ON_CRASH|KEXEC_PRESERVE_CONTEXT)) {
rc = load_crashdump_segments(info, modified_cmdline,
max_addr, 0);
if (rc < 0)
--- a/kexec/arch/i386/kexec-x86-common.c
+++ b/kexec/arch/i386/kexec-x86-common.c
@@ -174,7 +174,8 @@ int get_memory_ranges(struct memory_rang
* Override user values only if kernel exported values are
* subset of user defined values.
*/
- if (kexec_flags & KEXEC_ON_CRASH) {
+ if ((kexec_flags & KEXEC_ON_CRASH) &&
+ !(kexec_flags & KEXEC_PRESERVE_CONTEXT)) {
unsigned long long start, end;
ret = parse_iomem_single("Crash kernel\n", &start, &end);
--- a/kexec/crashdump.c
+++ b/kexec/crashdump.c
@@ -29,6 +29,7 @@
#include <elf.h>
#include "kexec.h"
#include "crashdump.h"
+#include "kexec-syscall.h"
/* include "crashdump-elf.c" twice to create two functions from one */
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