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	The hush shell dynamically allocates (and re-allocates) memory for the
argument strings in the "char *argv[]" argument vector passed to
commands.  Any code that modifies these pointers will cause serious
corruption of the malloc data structures and crash U-Boot, so make
sure the compiler can check that no such modifications are being done
by changing the code into "char * const argv[]".
This modification is the result of debugging a strange crash caused
after adding a new command, which used the following argument
processing code which has been working perfectly fine in all Unix
systems since version 6 - but not so in U-Boot:
int main (int argc, char **argv)
{
	while (--argc > 0 && **++argv == '-') {
/* ====> */	while (*++*argv) {
			switch (**argv) {
			case 'd':
				debug++;
				break;
			...
			default:
				usage ();
			}
		}
	}
	...
}
The line marked "====>" will corrupt the malloc data structures and
usually cause U-Boot to crash when the next command gets executed by
the shell.  With the modification, the compiler will prevent this with
an
	error: increment of read-only location '*argv'
N.B.: The code above can be trivially rewritten like this:
	while (--argc > 0 && **++argv == '-') {
		char *arg = *argv;
		while (*++arg) {
			switch (*arg) {
			...
Signed-off-by: Wolfgang Denk <wd@denx.de>
Acked-by: Mike Frysinger <vapier@gentoo.org>
		
	
			
		
			
				
	
	
		
			190 lines
		
	
	
		
			5.5 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			190 lines
		
	
	
		
			5.5 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /* SPARC code for booting linux 2.6
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|  *
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|  * (C) Copyright 2007
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|  * Daniel Hellstrom, Gaisler Research, daniel@gaisler.com.
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|  *
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|  * See file CREDITS for list of people who contributed to this
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|  * project.
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|  *
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|  * This program is free software; you can redistribute it and/or
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|  * modify it under the terms of the GNU General Public License as
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|  * published by the Free Software Foundation; either version 2 of
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|  * the License, or (at your option) any later version.
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|  *
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|  * This program is distributed in the hope that it will be useful,
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|  * but WITHOUT ANY WARRANTY; without even the implied warranty of
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|  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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|  * GNU General Public License for more details.
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|  *
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|  * You should have received a copy of the GNU General Public License
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|  * along with this program; if not, write to the Free Software
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|  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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|  * MA 02111-1307 USA
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|  */
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| 
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| #include <common.h>
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| #include <command.h>
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| #include <asm/byteorder.h>
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| #include <asm/prom.h>
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| #include <asm/cache.h>
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| #include <image.h>
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| 
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| #define PRINT_KERNEL_HEADER
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| 
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| extern image_header_t header;
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| extern void srmmu_init_cpu(unsigned int entry);
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| extern void prepare_bootargs(char *bootargs);
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| 
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| #ifdef CONFIG_USB_UHCI
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| extern int usb_lowlevel_stop(void);
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| #endif
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| 
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| /* sparc kernel argument (the ROM vector) */
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| struct linux_romvec *kernel_arg_promvec;
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| 
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| /* page szie is 4k */
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| #define PAGE_SIZE 0x1000
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| #define RAMDISK_IMAGE_START_MASK	0x07FF
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| #define RAMDISK_PROMPT_FLAG		0x8000
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| #define RAMDISK_LOAD_FLAG		0x4000
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| struct __attribute__ ((packed)) {
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| 	char traptable[PAGE_SIZE];
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| 	char swapper_pg_dir[PAGE_SIZE];
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| 	char pg0[PAGE_SIZE];
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| 	char pg1[PAGE_SIZE];
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| 	char pg2[PAGE_SIZE];
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| 	char pg3[PAGE_SIZE];
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| 	char empty_bad_page[PAGE_SIZE];
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| 	char empty_bad_page_table[PAGE_SIZE];
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| 	char empty_zero_page[PAGE_SIZE];
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| 	unsigned char hdr[4];	/* ascii "HdrS" */
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| 	/* 00.02.06.0b is for Linux kernel 2.6.11 */
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| 	unsigned char linuxver_mega_major;
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| 	unsigned char linuxver_major;
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| 	unsigned char linuxver_minor;
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| 	unsigned char linuxver_revision;
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| 	/* header version 0x0203 */
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| 	unsigned short hdr_ver;
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| 	union __attribute__ ((packed)) {
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| 		struct __attribute__ ((packed)) {
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| 			unsigned short root_flags;
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| 			unsigned short root_dev;
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| 			unsigned short ram_flags;
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| 			unsigned int sparc_ramdisk_image;
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| 			unsigned int sparc_ramdisk_size;
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| 			unsigned int reboot_command;
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| 			unsigned int resv[3];
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| 			unsigned int end;
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| 		} ver_0203;
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| 	} hdr_input;
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| } *linux_hdr;
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| 
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| /* temporary initrd image holder */
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| image_header_t ihdr;
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| 
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| void arch_lmb_reserve(struct lmb *lmb)
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| {
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| 	/* Reserve the space used by PROM and stack. This is done
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| 	 * to avoid that the RAM image is copied over stack or
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| 	 * PROM.
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| 	 */
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| 	lmb_reserve(lmb, CONFIG_SYS_RELOC_MONITOR_BASE, CONFIG_SYS_RAM_END);
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| }
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| 
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| /* boot the linux kernel */
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| int do_bootm_linux(int flag, int argc, char * const argv[], bootm_headers_t * images)
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| {
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| 	char *bootargs;
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| 	ulong initrd_start, initrd_end;
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| 	ulong rd_len;
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| 	unsigned int data, len, checksum;
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| 	unsigned int initrd_addr, kernend;
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| 	void (*kernel) (struct linux_romvec *, void *);
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| 	struct lmb *lmb = &images->lmb;
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| 	int ret;
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| 
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| 	if ((flag != 0) && (flag != BOOTM_STATE_OS_GO))
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| 		return 1;
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| 
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| 	/* Get virtual address of kernel start */
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| 	linux_hdr = (void *)images->os.load;
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| 
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| 	/* */
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| 	kernel = (void (*)(struct linux_romvec *, void *))images->ep;
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| 
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| 	/* check for a SPARC kernel */
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| 	if ((linux_hdr->hdr[0] != 'H') ||
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| 	    (linux_hdr->hdr[1] != 'd') ||
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| 	    (linux_hdr->hdr[2] != 'r') || (linux_hdr->hdr[3] != 'S')) {
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| 		puts("Error reading header of SPARC Linux kernel, aborting\n");
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| 		goto error;
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| 	}
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| #ifdef PRINT_KERNEL_HEADER
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| 	printf("## Found SPARC Linux kernel %d.%d.%d ...\n",
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| 	       linux_hdr->linuxver_major,
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| 	       linux_hdr->linuxver_minor, linux_hdr->linuxver_revision);
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| #endif
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| 
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| #ifdef CONFIG_USB_UHCI
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| 	usb_lowlevel_stop();
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| #endif
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| 
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| 	/* set basic boot params in kernel header now that it has been
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| 	 * extracted and is writeable.
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| 	 */
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| 
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| 	/* Calc length of RAM disk, if zero no ramdisk available */
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| 	rd_len = images->rd_end - images->rd_start;
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| 
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| 	if (rd_len) {
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| 		ret = boot_ramdisk_high(lmb, images->rd_start, rd_len,
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| 					&initrd_start, &initrd_end);
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| 		if (ret) {
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| 			puts("### Failed to relocate RAM disk\n");
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| 			goto error;
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| 		}
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| 
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| 		/* Update SPARC kernel header so that Linux knows
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| 		 * what is going on and where to find RAM disk.
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| 		 *
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| 		 * Set INITRD Image address relative to RAM Start
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| 		 */
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| 		linux_hdr->hdr_input.ver_0203.sparc_ramdisk_image =
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| 		    initrd_start - CONFIG_SYS_RAM_BASE;
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| 		linux_hdr->hdr_input.ver_0203.sparc_ramdisk_size = rd_len;
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| 		/* Clear READ ONLY flag if set to non-zero */
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| 		linux_hdr->hdr_input.ver_0203.root_flags = 1;
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| 		/* Set root device to: Root_RAM0 */
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| 		linux_hdr->hdr_input.ver_0203.root_dev = 0x100;
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| 		linux_hdr->hdr_input.ver_0203.ram_flags = 0;
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| 	} else {
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| 		/* NOT using RAMDISK image, overwriting kernel defaults */
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| 		linux_hdr->hdr_input.ver_0203.sparc_ramdisk_image = 0;
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| 		linux_hdr->hdr_input.ver_0203.sparc_ramdisk_size = 0;
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| 		/* Leave to kernel defaults
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| 		   linux_hdr->hdr_input.ver_0203.root_flags = 1;
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| 		   linux_hdr->hdr_input.ver_0203.root_dev = 0;
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| 		   linux_hdr->hdr_input.ver_0203.ram_flags = 0;
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| 		 */
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| 	}
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| 
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| 	/* Copy bootargs from bootargs variable to kernel readable area */
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| 	bootargs = getenv("bootargs");
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| 	prepare_bootargs(bootargs);
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| 
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| 	/* turn on mmu & setup context table & page table for process 0 (kernel) */
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| 	srmmu_init_cpu((unsigned int)kernel);
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| 
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| 	/* Enter SPARC Linux kernel
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| 	 * From now on the only code in u-boot that will be
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| 	 * executed is the PROM code.
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| 	 */
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| 	kernel(kernel_arg_promvec, (void *)images->ep);
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| 
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| 	/* It will never come to this... */
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| 	while (1) ;
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| 
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|       error:
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| 	return 1;
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| }
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