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arm: mvebu: Espressobin: Fix default env variables

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Default env variables on Espressobin boards are broken since commit c4df0f6f31
("arm: mvebu: Espressobin: Set default value for $fdtfile env variable") as well
as the 'env default -a' command.

The algorithm to find free space in the default_environment[] array returns
after the first env variable instead of the correct position of the last
variable, where there is allocated free space.

This causes that U-Boot board_late_init() function to overwrite a portion of the
default environment with $ethXaddr and $fdtfile variables immediately after the
first env variable and so it is overwriting other variables.

This patch also adds an additional null byte to terminate the environment array.

But U-Boot board_late_init() function do not fill this nul byte explicitly. And
because of that, U-Boot is later trying to interpret remaining buffer as a
continuation of variable list. Normally buffer should be empty but due to the
above issue, it contains garbage from remaining env variables.

For example 'env default -a' command results in damaging variable names. It was
observed that scritaddr variable name was changed to criptaddr (without leading
's').

This bug was reported and discussed on the Armbian forum:
https://forum.armbian.com/topic/19564-making-espressobin-v7-work-in-2022/?do=findComment&comment=138136

Fix these issues in two steps:

1) Change code which finds free space for dynamic env variables in
default_environment[] array by jumping to the end of the variable list instead
of jumping after the first defined variable. [By Derek]

2) Add code which appends terminating nul byte as indication of the end of the
env list, after the last nul term env string. [By Pali]

Fixes: c4df0f6f31 ("arm: mvebu: Espressobin: Set default value for $fdtfile env variable")
Signed-off-by: Derek LaHousse <derek@seaofdirac.org>
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Stefan Roese <sr@denx.de>
This commit is contained in:
Derek LaHousse 2022-12-12 07:34:17 +01:00 committed by Stefan Roese
parent 7a7b0856ca
commit 3a68fda33f
1 changed files with 17 additions and 3 deletions
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20
board/Marvell/mvebu_armada-37xx/board.c
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@ -99,9 +99,16 @@ int board_late_init(void)
if (!of_machine_is_compatible("globalscale,espressobin"))
return 0;
/* Find free buffer in default_environment[] for new variables */
while (*ptr != '\0' && *(ptr+1) != '\0') ptr++;
ptr += 2;
/*
* Find free space for new variables in default_environment[] array.
* Free space is after the last variable, each variable is termined
* by nul byte and after the last variable is additional nul byte.
* Move ptr to the position where new variable can be filled.
*/
while (*ptr != '\0') {
do { ptr++; } while (*ptr != '\0');
ptr++;
}
/*
* Ensure that 'env default -a' does not erase permanent MAC addresses
@ -145,6 +152,13 @@ int board_late_init(void)
strcpy(ptr, "fdtfile=marvell/armada-3720-espressobin-emmc.dtb");
else
strcpy(ptr, "fdtfile=marvell/armada-3720-espressobin.dtb");
ptr += strlen(ptr) + 1;
/*
* After the last variable (which is nul term string) append another nul
* byte which terminates the list. So everything after ptr is ignored.
*/
*ptr = '\0';
return 0;
}