generic: improve MIPS kexec support

It is based on patches from the linux-longsoon-community git tree:
http://dev.lemote.com/cgit/linux-loongson-community.git/

Now the kernel can use the command line parameter from kexec-tools.

Runtime tested on ar71xx with 2.6.39.4 (the wathdog must be stopped
before executing the new kernel). Compile tested with lantiq (3.1.4)
and brcm47xx (3.0.12).

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@29674 3c298f89-4303-0410-b956-a3cf2f4a3e73

1 files changed, 186 insertions, 0 deletions

diff --git a/target/linux/generic/patches-3.1/335-mips-kexec-cleanup-kexec-tools-parameter-handling.patch b/target/linux/generic/patches-3.1/335-mips-kexec-cleanup-kexec-tools-parameter-handling.patch
new file mode 100644
index 0000000000..abc89712ba
--- /dev/null
+++ b/target/linux/generic/patches-3.1/335-mips-kexec-cleanup-kexec-tools-parameter-handling.patch
@@ -0,0 +1,186 @@
+--- a/arch/mips/kernel/machine_kexec.c
++++ b/arch/mips/kernel/machine_kexec.c
+@@ -23,67 +23,104 @@ void (*relocated_kexec_smp_wait) (void *
+ atomic_t kexec_ready_to_reboot = ATOMIC_INIT(0);
+ #endif
+ 
+-static void machine_kexec_init_args(void)
++#define KEXEC_MIPS_ARGV_BUF_SIZE	COMMAND_LINE_SIZE
++#define KEXEC_MIPS_ARGV_MAX_ARGS	(COMMAND_LINE_SIZE / 15)
++
++char kexec_argv_buf[KEXEC_MIPS_ARGV_BUF_SIZE] __kexec;
++int kexec_argv[KEXEC_MIPS_ARGV_MAX_ARGS] __kexec;
++
++static void
++machine_kexec_print_args(void)
+ {
+-	kexec_args[0] = fw_arg0;
+-	kexec_args[1] = fw_arg1;
+-	kexec_args[2] = fw_arg2;
+-	kexec_args[3] = fw_arg3;
++	int i;
+ 
+ 	pr_info("kexec_args[0] (argc): %lu\n", kexec_args[0]);
+ 	pr_info("kexec_args[1] (argv): %p\n", (void *)kexec_args[1]);
+ 	pr_info("kexec_args[2] (env ): %p\n", (void *)kexec_args[2]);
+ 	pr_info("kexec_args[3] (desc): %p\n", (void *)kexec_args[3]);
+-}
+ 
+-#define ARGV_MAX_ARGS (COMMAND_LINE_SIZE / 15)
++	for (i = 0; i < kexec_args[0]; i++)
++		pr_info("kexec_argv[%d] = %p, %s\n", i,
++			(char *)kexec_argv[i], (char *)kexec_argv[i]);
++}
+ 
+-int machine_kexec_pass_args(struct kimage *image)
++static void
++machine_kexec_init_argv(struct kimage *image)
+ {
+-	int i, argc = 0;
+-	char *bootloader = "kexec";
+-	int *kexec_argv = (int *)kexec_args[1];
++	void __user *buf;
++	size_t bufsz;
++	size_t size;
++	int i;
+ 
++	bufsz = 0;
+ 	for (i = 0; i < image->nr_segments; i++) {
+-		if (!strncmp(bootloader, (char *)image->segment[i].buf,
+-				strlen(bootloader))) {
+-			/*
+-			 * convert command line string to array
+-			 * of parameters (as bootloader does).
+-			 */
+-			/*
+-			 * Note: we do treat the 1st string "kexec" as an
+-			 * argument ;-) so, argc here is 1.
+-			 */
+-			char *str = (char *)image->segment[i].buf;
+-			char *ptr = strchr(str, ' ');
+-			char *kbuf = (char *)kexec_argv[0];
+-			/* Whenever --command-line or --append used, "kexec" is copied */
+-			argc = 1;
+-			/* Parse the offset */
+-			while (ptr && (ARGV_MAX_ARGS > argc)) {
+-				*ptr = '\0';
+-				if (ptr[1] != ' ' && ptr[1] != '\0') {
+-					int offt = (int)(ptr - str + 1);
+-					kexec_argv[argc] = (int)kbuf + offt;
+-					argc++;
+-				}
+-				ptr = strchr(ptr + 1, ' ');
+-			}
+-			if (argc > 1) {
+-				/* Copy to kernel space */
+-				copy_from_user(kbuf, (char *)image->segment[i].buf, image->segment[i].bufsz);
+-				fw_arg0 = kexec_args[0] = argc;
+-			}
+-			break;
++		struct kexec_segment *seg;
++
++		seg = &image->segment[i];
++		if (seg->bufsz < 6)
++			continue;
++
++		if (strncmp((char *) seg->buf, "kexec", 5))
++			continue;
++
++		/* don't copy "kexec" */
++		buf = seg->buf + 5;
++		bufsz = seg->bufsz - 5;
++		break;
++	}
++
++	if (i >= image->nr_segments)
++		return;
++
++	size = KEXEC_MIPS_ARGV_BUF_SIZE - 1;
++	size = min(size, bufsz);
++	if (size < bufsz)
++		pr_warn("kexec command line truncated to %d bytes\n", size);
++
++	/* Copy to kernel space */
++	copy_from_user(kexec_argv_buf, buf, size);
++}
++
++static void
++machine_kexec_parse_argv(struct kimage *image)
++{
++	char *reboot_code_buffer;
++	int reloc_delta;
++	char *ptr;
++	int argc;
++	int i;
++
++	ptr = kexec_argv_buf;
++	argc = 0;
++
++	/*
++	 * convert command line string to array of parameters
++	 * (as bootloader does).
++	 */
++	while (ptr && *ptr && (KEXEC_MIPS_ARGV_MAX_ARGS > argc)) {
++		if (*ptr == ' ') {
++			*ptr++ = '\0';
++			continue;
+ 		}
++
++		kexec_argv[argc++] = (int) ptr;
++		ptr = strchr(ptr, ' ');
+ 	}
+ 
+-	pr_info("argc = %lu\n", kexec_args[0]);
+-	for (i = 0; i < kexec_args[0]; i++)
+-		pr_info("argv[%d] = %p, %s\n", i, (char *)kexec_argv[i], (char *)kexec_argv[i]);
++	if (!argc)
++		return;
+ 
+-	return 0;
++	kexec_args[0] = argc;
++	kexec_args[1] = (int) kexec_argv;
++	kexec_args[2] = 0;
++	kexec_args[3] = 0;
++
++	reboot_code_buffer = page_address(image->control_code_page);
++	reloc_delta = reboot_code_buffer - (char *) &__start___kexec_relocate;
++
++	kexec_args[1] += reloc_delta;
++	for (i = 0; i < argc; i++)
++		kexec_argv[i] += reloc_delta;
+ }
+ 
+ int
+@@ -95,8 +132,14 @@ machine_kexec_prepare(struct kimage *kim
+ 	 *
+ 	 * This can be overrided by _machine_kexec_prepare().
+ 	 */
+-	machine_kexec_init_args();
+-	machine_kexec_pass_args(kimage);
++
++	kexec_args[0] = fw_arg0;
++	kexec_args[1] = fw_arg1;
++	kexec_args[2] = fw_arg2;
++	kexec_args[3] = fw_arg3;
++
++	machine_kexec_init_argv(kimage);
++	machine_kexec_parse_argv(kimage);
+ 
+ 	if (_machine_kexec_prepare)
+ 		return _machine_kexec_prepare(kimage);
+@@ -152,11 +195,13 @@ machine_kexec(struct kimage *image)
+ 	pr_info("kexec_indirection_page = %p\n",
+ 			(void *)kexec_indirection_page);
+ 
++	pr_info("Copy kexec_relocate section from %p to reboot_code_buffer: %p\n",
++			&__start___kexec_relocate, (void *)reboot_code_buffer);
++
+ 	memcpy((void *)reboot_code_buffer, &__start___kexec_relocate,
+ 	       kexec_relocate_size);
+ 
+-	pr_info("Copy kexec_relocate section from %p to reboot_code_buffer: %p\n",
+-			&__start___kexec_relocate, (void *)reboot_code_buffer);
++	machine_kexec_print_args();
+ 
+ 	/*
+ 	 * The generic kexec code builds a page list with physical