[PATCH] Add method to pass initrd through cmdline

[Hui Li]

Problem description:
Under loongson platform,use command:
kexec -l vmlinux... --append="root=UUID=28e1..." --initrd=...
kexec -e
quick restart failed.

The reason of this problem:
The kernel cannot parse the UUID,UUID is parsed in the initrd.
Loongson platform obtain the initrd through cmdline in kernel.
In kexec-tools, initrd is not added to cmdline.

The solution:
Add initrd parameter to cmdline. and add a CONFIG_LOONGSON configuration
to distinguish PAGE_OFFSET between different platforms under mips.

Signed-off-by: Hui Li <lihui at loongson.cn>
---
 configure.ac                     |  5 ++++
 kexec/arch/mips/crashdump-mips.h |  6 ++++-
 kexec/arch/mips/kexec-elf-mips.c | 43 ++++++++++++++++++++++++++++++++
 3 files changed, 53 insertions(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index cf8e8a2..26bfbcd 100644
--- a/configure.ac
+++ b/configure.ac
@@ -111,6 +111,11 @@ AC_ARG_WITH([booke],
 		AC_DEFINE(CONFIG_BOOKE,1,
 			[Define to build for BookE]))
 
+AC_ARG_WITH([loongson],
+		AC_HELP_STRING([--with-loongson],[build for loongson]),
+		AC_DEFINE(CONFIG_LOONGSON,1,
+			[Define to build for LoongsoN]))
+
 dnl ---Programs
 dnl To specify a different compiler, just 'export CC=/path/to/compiler'
 if test "${build}" != "${host}" ; then
diff --git a/kexec/arch/mips/crashdump-mips.h b/kexec/arch/mips/crashdump-mips.h
index 7edd859..d53c696 100644
--- a/kexec/arch/mips/crashdump-mips.h
+++ b/kexec/arch/mips/crashdump-mips.h
@@ -5,7 +5,11 @@ struct kexec_info;
 int load_crashdump_segments(struct kexec_info *info, char *mod_cmdline,
 				unsigned long max_addr, unsigned long min_base);
 #ifdef __mips64
-#define PAGE_OFFSET	0xa800000000000000ULL
+#ifdef CONFIG_LOONGSON
+#define PAGE_OFFSET 0xFFFFFFFF80000000ULL
+#else
+#define PAGE_OFFSET 0xa800000000000000ULL
+#endif
 #define MAXMEM		0
 #else
 #define PAGE_OFFSET	0x80000000
diff --git a/kexec/arch/mips/kexec-elf-mips.c b/kexec/arch/mips/kexec-elf-mips.c
index a2d11fc..1de418e 100644
--- a/kexec/arch/mips/kexec-elf-mips.c
+++ b/kexec/arch/mips/kexec-elf-mips.c
@@ -40,6 +40,44 @@ static const int probe_debug = 0;
 #define CMDLINE_PREFIX "kexec "
 static char cmdline_buf[COMMAND_LINE_SIZE] = CMDLINE_PREFIX;
 
+/* 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 initrd parameters to command line. */
+static int cmdline_add_initrd(char *cmdline, unsigned long addr, char *new_para)
+{
+	int cmdlen, len;
+	char str[30], *ptr;
+
+	ptr = str;
+	strcpy(str, new_para);
+	ptr += strlen(str);
+	ultoa(addr, ptr);
+	len = strlen(str);
+	cmdlen = strlen(cmdline) + len;
+	if (cmdlen > (COMMAND_LINE_SIZE - 1))
+		die("Command line overflow\n");
+	strcat(cmdline, str);
+
+	return 0;
+}
+
+
 int elf_mips_probe(const char *buf, off_t len)
 {
 	struct mem_ehdr ehdr;
@@ -171,6 +209,11 @@ int elf_mips_load(int argc, char **argv, const char *buf, off_t len,
 		/* Now that the buffer for initrd is prepared, update the dtb
 		 * with an appropriate location */
 		dtb_set_initrd(&dtb_buf, &dtb_length, initrd_base, initrd_base + initrd_size);
+
+		/* Add the initrd parameters to cmdline */
+		cmdline_add_initrd(cmdline_buf, PAGE_OFFSET + initrd_base, " rd_start=");
+		cmdline_add_initrd(cmdline_buf, initrd_size, " rd_size=");
+
 	}
 
 
-- 
2.20.1