kexec-tools: mips: support big-endian mips (repost)

[ Reposted with correct linux-mips address ]

Hi,

this patch switches the mips support in kexec-tools around a little bit.
All the files and directories containing "mipsel" have been renamed
to contain "mips" instead.

This is kind of consistent with the way that ARCH=mips in the kernel
works for both big and little endian.

After a small amount of tweaking, which is also included in this patch, the
code compiles and works fine for big endian mips as well as small endian
mips. All you need to do is compile using an appropriate compiler.

That is to say, kexec-tools's build system doesn't need to
be told about which endienness the code is being compiled for.

I have added kept mipsel as a supported "architecture" via ./configure,
though its just an alias for mips now. This is consistent with how
other architectures such as sh are treated. But I'm happy to remove
mipsel from ./configure if the mips people want that.

I tested this patch using qemu and the 2.6.24.3 tag of the mips-2.6 git
tree compiled for the qemu machine type for both big and little endian.
The qemu machine type has subsequently been removed, and kexec-tools
needs some work in order to function with qemu - as far as I understand
the way the boot parameters are passed needs to be fixed, likely
in purgatory. However, this is not related to the changes
introduced in this patch.

I intend to merge this patch into kexec-tools-testing if
no alarm bells are sounded.

Signed-off-by: Simon Horman <horms@verge.net.au>

1 files changed, 183 insertions, 0 deletions

diff --git a/kexec/arch/mips/kexec-elf-mips.c b/kexec/arch/mips/kexec-elf-mips.c
new file mode 100644
index 0000000..8220829
--- /dev/null
+++ b/kexec/arch/mips/kexec-elf-mips.c
@@ -0,0 +1,183 @@
+/*
+ * kexec-elf-mips.c - kexec Elf loader for mips
+ * Copyright (C) 2007 Francesco Chiechi, Alessandro Rubini
+ * Copyright (C) 2007 Tvblob s.r.l.
+ *
+ * derived from ../ppc/kexec-elf-ppc.c
+ * Copyright (C) 2004 Albert Herranz
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2.  See the file COPYING for more details.
+*/
+
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <getopt.h>
+#include <elf.h>
+#include <boot/elf_boot.h>
+#include <ip_checksum.h>
+#include "../../kexec.h"
+#include "../../kexec-elf.h"
+#include "kexec-mips.h"
+#include <arch/options.h>
+
+static const int probe_debug = 0;
+
+#define BOOTLOADER         "kexec"
+#define MAX_COMMAND_LINE   256
+
+#define UPSZ(X) ((sizeof(X) + 3) & ~3)
+static struct boot_notes {
+	Elf_Bhdr hdr;
+	Elf_Nhdr bl_hdr;
+	unsigned char bl_desc[UPSZ(BOOTLOADER)];
+	Elf_Nhdr blv_hdr;
+	unsigned char blv_desc[UPSZ(BOOTLOADER_VERSION)];
+	Elf_Nhdr cmd_hdr;
+	unsigned char command_line[0];
+} elf_boot_notes = {
+	.hdr = {
+		.b_signature = 0x0E1FB007,
+		.b_size = sizeof(elf_boot_notes),
+		.b_checksum = 0,
+		.b_records = 3,
+	},
+	.bl_hdr = {
+		.n_namesz = 0,
+		.n_descsz = sizeof(BOOTLOADER),
+		.n_type = EBN_BOOTLOADER_NAME,
+	},
+	.bl_desc = BOOTLOADER,
+	.blv_hdr = {
+		.n_namesz = 0,
+		.n_descsz = sizeof(BOOTLOADER_VERSION),
+		.n_type = EBN_BOOTLOADER_VERSION,
+	},
+	.blv_desc = BOOTLOADER_VERSION,
+	.cmd_hdr = {
+		.n_namesz = 0,
+		.n_descsz = 0,
+		.n_type = EBN_COMMAND_LINE,
+	},
+};
+
+
+#define OPT_APPEND	(OPT_ARCH_MAX+0)
+
+int elf_mips_probe(const char *buf, off_t len)
+{
+
+	struct mem_ehdr ehdr;
+	int result;
+	result = build_elf_exec_info(buf, len, &ehdr, 0);
+	if (result < 0) {
+		goto out;
+	}
+
+	/* Verify the architecuture specific bits */
+	if (ehdr.e_machine != EM_MIPS) {
+		/* for a different architecture */
+		if (probe_debug) {
+			fprintf(stderr, "Not for this architecture.\n");
+		}
+		result = -1;
+		goto out;
+	}
+	result = 0;
+ out:
+	free_elf_info(&ehdr);
+	return result;
+}
+
+void elf_mips_usage(void)
+{
+	printf("    --command-line=STRING Set the kernel command line to "
+			"STRING.\n"
+	       "    --append=STRING       Set the kernel command line to "
+			"STRING.\n");
+}
+
+int elf_mips_load(int argc, char **argv, const char *buf, off_t len,
+	struct kexec_info *info)
+{
+	struct mem_ehdr ehdr;
+	char *arg_buf;
+	size_t arg_bytes;
+	unsigned long arg_base;
+	struct boot_notes *notes;
+	size_t note_bytes;
+	const char *command_line;
+	int command_line_len;
+	unsigned char *setup_start;
+	uint32_t setup_size;
+	int opt;
+	static const struct option options[] = {
+		KEXEC_ARCH_OPTIONS
+		{"command-line", 1, 0, OPT_APPEND},
+		{"append",       1, 0, OPT_APPEND},
+		{0, 0, 0, 0},
+	};
+
+	static const char short_options[] = KEXEC_ARCH_OPT_STR "d";
+
+	command_line = 0;
+	while ((opt = getopt_long(argc, argv, short_options,
+				  options, 0)) != -1) {
+		switch (opt) {
+		default:
+			/* Ignore core options */
+			if (opt < OPT_ARCH_MAX) {
+				break;
+			}
+		case '?':
+			usage();
+			return -1;
+		case OPT_APPEND:
+			command_line = optarg;
+			break;
+		}
+	}
+	command_line_len = 0;
+	setup_simple_regs.spr9 = 0;
+	if (command_line) {
+		command_line_len = strlen(command_line) + 1;
+		setup_simple_regs.spr9 = 2;
+	}
+
+	/* Load the ELF executable */
+	elf_exec_build_load(info, &ehdr, buf, len, 0);
+
+	setup_start = setup_simple_start;
+	setup_size = setup_simple_size;
+	setup_simple_regs.spr8 = ehdr.e_entry;
+
+	note_bytes = sizeof(elf_boot_notes) + ((command_line_len + 3) & ~3);
+	arg_bytes = note_bytes + ((setup_size + 3) & ~3);
+
+	arg_buf = xmalloc(arg_bytes);
+	arg_base = add_buffer_virt(info,
+		 arg_buf, arg_bytes, arg_bytes, 4, 0, elf_max_addr(&ehdr), 1);
+
+	notes = (struct boot_notes *)(arg_buf + ((setup_size + 3) & ~3));
+
+	memcpy(arg_buf, setup_start, setup_size);
+	memcpy(notes, &elf_boot_notes, sizeof(elf_boot_notes));
+	memcpy(notes->command_line, command_line, command_line_len);
+
+	notes->hdr.b_size = note_bytes;
+	notes->cmd_hdr.n_descsz = command_line_len;
+	notes->hdr.b_checksum = compute_ip_checksum(notes, note_bytes);
+
+	info->entry = (void *)arg_base;
+
+	return 0;
+}
+