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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>
114 lines
3.2 KiB
C
114 lines
3.2 KiB
C
/*
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* (C) Copyright 2004
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* Wolfgang Denk, DENX Software Engineering, wd@denx.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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#include <common.h>
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#include <command.h>
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#include <malloc.h>
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#include <asm/immap.h>
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/* Prototypes */
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int do_reset (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]);
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int checkboard (void) {
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ulong val;
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uchar val8;
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puts ("Board: ");
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puts("Freescale M5249EVB");
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val8 = ((uchar)~((uchar)mbar2_readLong(MCFSIM_GPIO1_READ) >> 4)) & 0xf;
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printf(" (Switch=%1X)\n", val8);
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/*
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* Set LED on
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*/
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val = mbar2_readLong(MCFSIM_GPIO1_OUT) & ~CONFIG_SYS_GPIO1_LED;
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mbar2_writeLong(MCFSIM_GPIO1_OUT, val); /* Set LED on */
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return 0;
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};
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phys_size_t initdram (int board_type) {
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unsigned long junk = 0xa5a59696;
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/*
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* Note:
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* RC = ([(RefreshTime/#rows) / (1/BusClk)] / 16) - 1
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*/
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#ifdef CONFIG_SYS_FAST_CLK
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/*
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* Busclk=70MHz, RefreshTime=64ms, #rows=4096 (4K)
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* SO=1, NAM=0, COC=0, RTIM=01 (6clk refresh), RC=39
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*/
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mbar_writeShort(MCFSIM_DCR, 0x8239);
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#elif CONFIG_SYS_PLL_BYPASS
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/*
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* Busclk=5.6448MHz, RefreshTime=64ms, #rows=8192 (8K)
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* SO=1, NAM=0, COC=0, RTIM=01 (6clk refresh), RC=02
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*/
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mbar_writeShort(MCFSIM_DCR, 0x8202);
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#else
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/*
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* Busclk=36MHz, RefreshTime=64ms, #rows=4096 (4K)
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* SO=1, NAM=0, COC=0, RTIM=01 (6clk refresh), RC=22 (562 bus clock cycles)
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*/
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mbar_writeShort(MCFSIM_DCR, 0x8222);
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#endif
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/*
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* SDRAM starts at 0x0000_0000, CASL=10, CBM=010, PS=10 (16bit port),
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* PM=1 (continuous page mode)
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*/
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/* RE=0 (keep auto-refresh disabled while setting up registers) */
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mbar_writeLong(MCFSIM_DACR0, 0x00003324);
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/* BAM=007c (bits 22,21 are bank selects; 256kB blocks) */
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mbar_writeLong(MCFSIM_DMR0, 0x01fc0001);
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/** Precharge sequence **/
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mbar_writeLong(MCFSIM_DACR0, 0x0000332c); /* Set DACR0[IP] (bit 3) */
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*((volatile unsigned long *) 0x00) = junk; /* write to a memory location to init. precharge */
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udelay(0x10); /* Allow several Precharge cycles */
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/** Refresh Sequence **/
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mbar_writeLong(MCFSIM_DACR0, 0x0000b324); /* Enable the refresh bit, DACR0[RE] (bit 15) */
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udelay(0x7d0); /* Allow gobs of refresh cycles */
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/** Mode Register initialization **/
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mbar_writeLong(MCFSIM_DACR0, 0x0000b364); /* Enable DACR0[IMRS] (bit 6); RE remains enabled */
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*((volatile unsigned long *) 0x800) = junk; /* Access RAM to initialize the mode register */
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return CONFIG_SYS_SDRAM_SIZE * 1024 * 1024;
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};
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int testdram (void) {
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/* TODO: XXX XXX XXX */
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printf ("DRAM test not implemented!\n");
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return (0);
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}
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