mirror of
https://github.com/brain-hackers/u-boot-brain
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![Wolfgang Denk](/assets/img/avatar_default.png)
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>
93 lines
2.4 KiB
C
93 lines
2.4 KiB
C
/*
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* (C) Copyright 2002
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* Daniel Engström, Omicron Ceti AB, daniel@omicron.se.
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*
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* (C) Copyright 2002
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* Sysgo Real-Time Solutions, GmbH <www.elinos.com>
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* Marius Groeger <mgroeger@sysgo.de>
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*
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* (C) Copyright 2002
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* Sysgo Real-Time Solutions, GmbH <www.elinos.com>
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* Alex Zuepke <azu@sysgo.de>
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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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* CPU specific code
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*/
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#include <common.h>
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#include <command.h>
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#include <asm/interrupt.h>
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int cpu_init_f(void)
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{
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/* initialize FPU, reset EM, set MP and NE */
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asm ("fninit\n" \
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"movl %cr0, %eax\n" \
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"andl $~0x4, %eax\n" \
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"orl $0x22, %eax\n" \
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"movl %eax, %cr0\n" );
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return 0;
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}
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int cpu_init_r(void)
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{
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/* Initialize core interrupt and exception functionality of CPU */
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cpu_init_interrupts ();
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return 0;
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}
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int do_reset(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
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{
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printf ("resetting ...\n");
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udelay(50000); /* wait 50 ms */
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disable_interrupts();
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reset_cpu(0);
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/*NOTREACHED*/
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return 0;
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}
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void flush_cache (unsigned long dummy1, unsigned long dummy2)
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{
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asm("wbinvd\n");
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return;
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}
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void __attribute__ ((regparm(0))) generate_gpf(void);
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/* segment 0x70 is an arbitrary segment which does not exist */
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asm(".globl generate_gpf\n"
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".hidden generate_gpf\n"
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".type generate_gpf, @function\n"
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"generate_gpf:\n"
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"ljmp $0x70, $0x47114711\n");
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void __reset_cpu(ulong addr)
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{
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printf("Resetting using i386 Triple Fault\n");
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set_vector(13, generate_gpf); /* general protection fault handler */
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set_vector(8, generate_gpf); /* double fault handler */
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generate_gpf(); /* start the show */
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}
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void reset_cpu(ulong addr) __attribute__((weak, alias("__reset_cpu")));
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