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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>
35 lines
755 B
C
35 lines
755 B
C
/*
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* flash.c - helper commands for working with GPIO-assisted flash
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*
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* Copyright (c) 2005-2009 Analog Devices Inc.
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*
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* Licensed under the GPL-2 or later.
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*/
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#include <common.h>
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#include <command.h>
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#include <asm/blackfin.h>
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#include "gpio_cfi_flash.h"
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int do_pf(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
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{
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ulong faddr = CONFIG_SYS_FLASH_BASE;
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ushort data;
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ulong dflg;
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if (argc > 1) {
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dflg = simple_strtoul(argv[1], NULL, 16);
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faddr |= (dflg << 21);
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gpio_cfi_flash_swizzle((void *)faddr);
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} else {
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data = bfin_read_PORTFIO();
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printf("Port F data %04x (PF4:%i)\n", data, !!(data & PF4));
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}
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return 0;
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}
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U_BOOT_CMD(pf, 3, 0, do_pf,
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"set/clear PF4 GPIO flash bank switch\n",
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"<pf4> - set PF4 GPIO pin state\n");
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