kexec-tools: x86_64 append command line options

o Modifying the command line agruments to append memmap= and elfcore=
  options for the capture kernel.

o Introducing get_crash_memory_ranges to traverse through /proc/iomem
  which will be useful when perparing elf-headers as we have to prepare
  elf headers for each chunck.

Signed-off-by: Murali M Chakravarthy <muralim@in.ibm.com>
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Maneesh Soni <maneesh@in.ibm.com>

2 files changed, 414 insertions, 0 deletions

diff --git a/kexec/arch/x86_64/crashdump-x86_64.c b/kexec/arch/x86_64/crashdump-x86_64.c
index 299d9d1..8f06eee 100644
--- a/kexec/arch/x86_64/crashdump-x86_64.c
+++ b/kexec/arch/x86_64/crashdump-x86_64.c
@@ -34,6 +34,401 @@
 #include "crashdump-x86_64.h"
 #include <x86/x86-linux.h>
 
+#define MAX_LINE	160
+
+extern struct arch_options_t arch_options;
+
+/* Forward Declaration. */
+static int exclude_crash_reserve_region(int *nr_ranges);
+
+/* Stores a sorted list of RAM memory ranges for which to create elf headers.
+ * A separate program header is created for backup region */
+static struct memory_range crash_memory_range[CRASH_MAX_MEMORY_RANGES];
+
+/* Memory region reserved for storing panic kernel and other data. */
+static struct memory_range crash_reserved_mem;
+
+/* Reads the appropriate file and retrieves the SYSTEM RAM regions for whom to
+ * create Elf headers. Keeping it separate from get_memory_ranges() as
+ * requirements are different in the case of normal kexec and crashdumps.
+ *
+ * Normal kexec needs to look at all of available physical memory irrespective
+ * of the fact how much of it is being used by currently running kernel.
+ * Crashdumps need to have access to memory regions actually being used by
+ * running  kernel. Expecting a different file/data structure than /proc/iomem
+ * 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)
+{
+	const char iomem[]= "/proc/iomem";
+	int memory_ranges = 0;
+	char line[MAX_LINE];
+	FILE *fp;
+	unsigned long long start, end;
+
+	fp = fopen(iomem, "r");
+	if (!fp) {
+		fprintf(stderr, "Cannot open %s: %s\n",
+			iomem, strerror(errno));
+		return -1;
+	}
+
+	/* 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++;
+
+	while(fgets(line, sizeof(line), fp) != 0) {
+		char *str;
+		int type, consumed, count;
+		if (memory_ranges >= CRASH_MAX_MEMORY_RANGES)
+			break;
+		count = sscanf(line, "%Lx-%Lx : %n",
+			&start, &end, &consumed);
+		if (count != 2)
+			continue;
+		str = line + consumed;
+#if 0
+		printf("%016Lx-%016Lx : %s",
+			start, end, str);
+#endif
+		/* Only Dumping memory of type System RAM. */
+		if (memcmp(str, "System RAM\n", 11) == 0) {
+			type = RANGE_RAM;
+		} else if (memcmp(str, "Crash kernel\n", 13) == 0) {
+				/* Reserved memory region. New kernel can
+				 * use this region to boot into. */
+				crash_reserved_mem.start = start;
+				crash_reserved_mem.end = end;
+				crash_reserved_mem.type = RANGE_RAM;
+				continue;
+		} else {
+			continue;
+		}
+
+		/* First 640K already registered */
+		if (start >= 0x00000000 && end <= 0x0009ffff)
+			continue;
+
+		crash_memory_range[memory_ranges].start = start;
+		crash_memory_range[memory_ranges].end = end;
+		crash_memory_range[memory_ranges].type = type;
+		memory_ranges++;
+
+		/* Segregate linearly mapped region. */
+		if ((MAXMEM - 1) >= start && (MAXMEM - 1) <= end) {
+			crash_memory_range[memory_ranges-1].end = MAXMEM -1;
+
+			/* Add segregated region. */
+			crash_memory_range[memory_ranges].start = MAXMEM;
+			crash_memory_range[memory_ranges].end = end;
+			crash_memory_range[memory_ranges].type = type;
+			memory_ranges++;
+		}
+	}
+	fclose(fp);
+	if (exclude_crash_reserve_region(&memory_ranges) < 0)
+		return -1;
+	*range = crash_memory_range;
+	*ranges = memory_ranges;
+#if 0
+	int i;
+	printf("CRASH MEMORY RANGES\n");
+	for(i = 0; i < memory_ranges; i++) {
+		start = crash_memory_range[i].start;
+		end = crash_memory_range[i].end;
+		printf("%016Lx-%016Lx\n", start, end);
+	}
+#endif
+	return 0;
+}
+
+/* Removes crash reserve region from list of memory chunks for whom elf program
+ * headers have to be created. Assuming crash reserve region to be a single
+ * continuous area fully contained inside one of the memory chunks */
+static int exclude_crash_reserve_region(int *nr_ranges)
+{
+	int i, j, tidx = -1;
+	unsigned long long cstart, cend;
+	struct memory_range temp_region;
+
+	/* Crash reserved region. */
+	cstart = crash_reserved_mem.start;
+	cend = crash_reserved_mem.end;
+
+	for (i = 0; i < (*nr_ranges); i++) {
+		unsigned long long mstart, mend;
+		mstart = crash_memory_range[i].start;
+		mend = crash_memory_range[i].end;
+		if (cstart < mend && cend > mstart) {
+			if (cstart != mstart && cend != mend) {
+				/* Split memory region */
+				crash_memory_range[i].end = cstart - 1;
+				temp_region.start = cend + 1;
+				temp_region.end = mend;
+				temp_region.type = RANGE_RAM;
+				tidx = i+1;
+			} else if (cstart != mstart)
+				crash_memory_range[i].end = cstart - 1;
+			else
+				crash_memory_range[i].start = cend + 1;
+		}
+	}
+	/* Insert split memory region, if any. */
+	if (tidx >= 0) {
+		if (*nr_ranges == CRASH_MAX_MEMORY_RANGES) {
+			/* No space to insert another element. */
+			fprintf(stderr, "Error: Number of crash memory ranges"
+					" excedeed the max limit\n");
+			return -1;
+		}
+		for (j = (*nr_ranges - 1); j >= tidx; j--)
+			crash_memory_range[j+1] = crash_memory_range[j];
+		crash_memory_range[tidx].start = temp_region.start;
+		crash_memory_range[tidx].end = temp_region.end;
+		crash_memory_range[tidx].type = temp_region.type;
+		(*nr_ranges)++;
+	}
+	return 0;
+}
+
+/* Adds a segment from list of memory regions which new kernel can use to
+ * boot. Segment start and end should be aligned to 1K boundary. */
+static int add_memmap(struct memory_range *memmap_p, unsigned long long addr,
+								size_t size)
+{
+	int i, j, nr_entries = 0, tidx = 0, align = 1024;
+	unsigned long long mstart, mend;
+
+	/* Do alignment check. */
+	if ((addr%align) || (size%align))
+		return -1;
+
+	/* Make sure at least one entry in list is free. */
+	for (i = 0; i < CRASH_MAX_MEMMAP_NR;  i++) {
+		mstart = memmap_p[i].start;
+		mend = memmap_p[i].end;
+		if (!mstart  && !mend)
+			break;
+		else
+			nr_entries++;
+	}
+	if (nr_entries == CRASH_MAX_MEMMAP_NR)
+		return -1;
+
+	for (i = 0; i < CRASH_MAX_MEMMAP_NR;  i++) {
+		mstart = memmap_p[i].start;
+		mend = memmap_p[i].end;
+		if (mstart == 0 && mend == 0)
+			break;
+		if (mstart <= (addr+size-1) && mend >=addr)
+			/* Overlapping region. */
+			return -1;
+		else if (addr > mend)
+			tidx = i+1;
+	}
+		/* Insert the memory region. */
+		for (j = nr_entries-1; j >= tidx; j--)
+			memmap_p[j+1] = memmap_p[j];
+		memmap_p[tidx].start = addr;
+		memmap_p[tidx].end = addr + size - 1;
+#if 0
+	printf("Memmap after adding segment\n");
+	for (i = 0; i < CRASH_MAX_MEMMAP_NR;  i++) {
+		mstart = memmap_p[i].start;
+		mend = memmap_p[i].end;
+		if (mstart == 0 && mend == 0)
+			break;
+		printf("%016llx - %016llx\n",
+			mstart, mend);
+	}
+#endif
+	return 0;
+}
+
+/* Removes a segment from list of memory regions which new kernel can use to
+ * boot. Segment start and end should be aligned to 1K boundary. */
+static int delete_memmap(struct memory_range *memmap_p, unsigned long long addr,
+								size_t size)
+{
+	int i, j, nr_entries = 0, tidx = -1, operation = 0, align = 1024;
+	unsigned long long mstart, mend;
+	struct memory_range temp_region;
+
+	/* Do alignment check. */
+	if ((addr%align) || (size%align))
+		return -1;
+
+	/* Make sure at least one entry in list is free. */
+	for (i = 0; i < CRASH_MAX_MEMMAP_NR;  i++) {
+		mstart = memmap_p[i].start;
+		mend = memmap_p[i].end;
+		if (!mstart  && !mend)
+			break;
+		else
+			nr_entries++;
+	}
+	if (nr_entries == CRASH_MAX_MEMMAP_NR)
+		/* List if full */
+		return -1;
+
+	for (i = 0; i < CRASH_MAX_MEMMAP_NR;  i++) {
+		mstart = memmap_p[i].start;
+		mend = memmap_p[i].end;
+		if (mstart == 0 && mend == 0)
+			/* Did not find the segment in the list. */
+			return -1;
+		if (mstart <= addr && mend >= (addr + size - 1)) {
+			if (mstart == addr && mend == (addr + size - 1)) {
+				/* Exact match. Delete region */
+				operation = -1;
+				tidx = i;
+				break;
+			}
+			if (mstart != addr && mend != (addr + size - 1)) {
+				/* Split in two */
+				memmap_p[i].end = addr - 1;
+				temp_region.start = addr + size;
+				temp_region.end = mend;
+				operation = 1;
+				tidx = i;
+				break;
+			}
+
+			/* No addition/deletion required. Adjust the existing.*/
+			if (mstart != addr) {
+				memmap_p[i].end = addr - 1;
+				break;
+			} else {
+				memmap_p[i].start = addr + size;
+				break;
+			}
+		}
+	}
+	if ((operation == 1) && tidx >=0) {
+		/* Insert the split memory region. */
+		for (j = nr_entries-1; j > tidx; j--)
+			memmap_p[j+1] = memmap_p[j];
+		memmap_p[tidx+1] = temp_region;
+	}
+	if ((operation == -1) && tidx >=0) {
+		/* Delete the exact match memory region. */
+		for (j = i+1; j < CRASH_MAX_MEMMAP_NR; j++)
+			memmap_p[j-1] = memmap_p[j];
+		memmap_p[j-1].start = memmap_p[j-1].end = 0;
+	}
+#if 0
+	printf("Memmap after deleting segment\n");
+	for (i = 0; i < CRASH_MAX_MEMMAP_NR;  i++) {
+		mstart = memmap_p[i].start;
+		mend = memmap_p[i].end;
+		if (mstart == 0 && mend == 0) {
+			break;
+		}
+		printf("%016llx - %016llx\n",
+			mstart, mend);
+	}
+#endif
+	return 0;
+}
+
+/* Converts unsigned long to ascii string. */
+static void ultoa(unsigned long i, char *str)
+{
+	int j = 0, k;
+	char tmp;
+
+	do {
+		str[j++] = i % 10 + '0';
+	} while ((i /=10) > 0);
+	str[j] = '\0';
+
+	/* Reverse the string. */
+	for (j = 0, k = strlen(str) - 1; j < k; j++, k--) {
+		tmp = str[k];
+		str[k] = str[j];
+		str[j] = tmp;
+	}
+}
+
+/* Adds the appropriate memmap= options to command line, indicating the
+ * memory regions the new kernel can use to boot into. */
+static int cmdline_add_memmap(char *cmdline, struct memory_range *memmap_p)
+{
+	int i, cmdlen, len, min_sizek = 100;
+	char str_mmap[256], str_tmp[20];
+
+	/* Exact map */
+	strcpy(str_mmap, " memmap=exactmap");
+	len = strlen(str_mmap);
+	cmdlen = strlen(cmdline) + len;
+	if (cmdlen > (COMMAND_LINE_SIZE - 1))
+		die("Command line overflow\n");
+	strcat(cmdline, str_mmap);
+
+	for (i = 0; i < CRASH_MAX_MEMMAP_NR;  i++) {
+		unsigned long startk, endk;
+		startk = (memmap_p[i].start/1024);
+		endk = ((memmap_p[i].end + 1)/1024);
+		if (!startk && !endk)
+			/* All regions traversed. */
+			break;
+
+		/* A region is not worth adding if region size < 100K. It eats
+		 * up precious command line length. */
+		if ((endk - startk) < min_sizek)
+			continue;
+		strcpy (str_mmap, " memmap=");
+		ultoa((endk-startk), str_tmp);
+		strcat (str_mmap, str_tmp);
+		strcat (str_mmap, "K@");
+		ultoa(startk, str_tmp);
+		strcat (str_mmap, str_tmp);
+		strcat (str_mmap, "K");
+		len = strlen(str_mmap);
+		cmdlen = strlen(cmdline) + len;
+		if (cmdlen > (COMMAND_LINE_SIZE - 1))
+			die("Command line overflow\n");
+		strcat(cmdline, str_mmap);
+	}
+#if 0
+		printf("Command line after adding memmap\n");
+		printf("%s\n", cmdline);
+#endif
+	return 0;
+}
+
+/* Adds the elfcorehdr= command line parameter to command line. */
+static int cmdline_add_elfcorehdr(char *cmdline, unsigned long addr)
+{
+	int cmdlen, len, align = 1024;
+	char str[30], *ptr;
+
+	/* Passing in elfcorehdr=xxxK format. Saves space required in cmdline.
+	 * Ensure 1K alignment*/
+	if (addr%align)
+		return -1;
+	addr = addr/align;
+	ptr = str;
+	strcpy(str, " elfcorehdr=");
+	ptr += strlen(str);
+	ultoa(addr, ptr);
+	strcat(str, "K");
+	len = strlen(str);
+	cmdlen = strlen(cmdline) + len;
+	if (cmdlen > (COMMAND_LINE_SIZE - 1))
+		die("Command line overflow\n");
+	strcat(cmdline, str);
+#if 0
+		printf("Command line after adding elfcorehdr\n");
+		printf("%s\n", cmdline);
+#endif
+	return 0;
+}
+
 /* Returns the virtual address of start of crash notes buffer for a cpu. */
 static int get_crash_notes_section_addr(int cpu, unsigned long long *addr)
 {
diff --git a/kexec/arch/x86_64/kexec-elf-x86_64.c b/kexec/arch/x86_64/kexec-elf-x86_64.c
index 5cac0e6..1f3c54d 100644
--- a/kexec/arch/x86_64/kexec-elf-x86_64.c
+++ b/kexec/arch/x86_64/kexec-elf-x86_64.c
@@ -32,6 +32,7 @@
 #include <elf.h>
 #include <x86/x86-linux.h>
 #include "../../kexec.h"
+#include "../../kexec-syscall.h"
 #include "../../kexec-elf.h"
 #include "../../kexec-elf-boot.h"
 #include "../i386/x86-linux-setup.h"
@@ -85,7 +86,9 @@ int elf_x86_64_load(int argc, char **argv, const char *buf, off_t len,
 {
 	struct mem_ehdr ehdr;
 	const char *command_line;
+	char *modified_cmdline;
 	int command_line_len;
+	int modified_cmdline_len;
 	const char *ramdisk;
 	unsigned long entry, max_addr;
 	int arg_style;
@@ -118,6 +121,8 @@ int elf_x86_64_load(int argc, char **argv, const char *buf, off_t len,
 	 */
 	arg_style = ARG_STYLE_ELF;
 	command_line = 0;
+	modified_cmdline = 0;
+	modified_cmdline_len = 0;
 	ramdisk = 0;
 	while((opt = getopt_long(argc, argv, short_options, options, 0)) != -1) {
 		switch(opt) {
@@ -156,6 +161,20 @@ int elf_x86_64_load(int argc, char **argv, const char *buf, off_t len,
 		command_line_len = strlen(command_line) +1;
 	}
 
+	/* Need to append some command line parameters internally in case of
+	 * taking crash dumps.
+	 */
+	if (info->kexec_flags & KEXEC_ON_CRASH) {
+		modified_cmdline = xmalloc(COMMAND_LINE_SIZE);
+		memset((void *)modified_cmdline, 0, COMMAND_LINE_SIZE);
+		if (command_line) {
+			strncpy(modified_cmdline, command_line,
+						COMMAND_LINE_SIZE);
+			modified_cmdline[COMMAND_LINE_SIZE - 1] = '\0';
+		}
+		modified_cmdline_len = strlen(modified_cmdline);
+	}
+
 	/* Load the ELF executable */
 	elf_exec_build_load(info, &ehdr, buf, len);