Re: MIPS: relocation issue

[Oleksij Rempel <o.rempel@pengutronix.de>]

Hi Antony,

thank you for your bug report. Can you please test my patch "[PATCH v1] MIPS: remove .bss 
to __rel_start overlay" with MMU enabled.

If it works, then we need to decide what should be done with MMU dependency.

On 28.01.20 07:46, Antony Pavlov wrote:
> Hi!
> 
> Since 28ed10d6a6 ("MIPS: relocation: add relocation support")
> iomem output on memory regions is invalid,
> all the code that rely on registered sdram memory regions
> after relocation can fail. E.g. the memtest commands fails
> on barebox.
> 
> How to reproduce the problem ov v2020.01.0:
> 
> $ wget https://www.barebox.org/download/barebox-2020.01.0.tar.bz2
> ...
> $ tar fx barebox-2020.01.0.tar.bz2
> $ cd barebox-2020.01.0
> $ export ARCH=mips
> $ export CROSS_COMPILE=mips-linux-gnu-
> $ make qemu-malta_defconfig
> $ sed -i "s/^.*CONFIG_CMD_MEMTEST.*/CONFIG_CMD_MEMTEST=y/" .config
> $ make
> $ qemu-system-mips -nodefaults -M malta -m 256 -nographic -serial stdio -monitor null -bios barebox-flash-image
> ...
> barebox@qemu malta:/ memtest
> Start iteration 1 of 1.
> Testing memory space: 0xa0865000 -> 0xafffffff:
> Starting data line test.
> Check for address bits stuck high.
> Check for address bits stuck low or shorted.
> Starting moving inversions test of RAM:
> Fill with address, compare, fill with inverted address, compare again
> 	[##########################################                       ]
> FAILURE (read/write): expected 0x03cca9f2, actual 0xa08126c4 at address 0xafb8f7c4.
> 
> Ooops, TLB miss on load or ifetch!
> 
> $ 0   : 00000000 00000000 fffffffb a085c900
> $ 4   : a0407e90 0000000a b80003f8 00000001
> $ 8   : a0858f28 00000000 00000053 00000008
> $12   : 00000000 00000000 0000005c 00000001
> $16   : 03ccab3c 03ccab3d a0825c48 00000000
> $20   : 00000000 00000001 a0853518 a085352c
> $24   : 00000018 a08124b8
> $28   : 00000000 8fb8fcf8 a0860000 03ccab3e
> Hi    : 0000000a
> Lo    : 00000000
> epc   : 03ccab3e
> ra    : 03ccab3e
> Status: 00000002
> Cause : 00000408
> Config: 80008482
> 
> ### ERROR ### Please RESET the board ###
> 
> 
> memtest for qemu-malta can be repaired by disabling relocation, e.g.
> 
> diff --git a/arch/mips/boot/start.S b/arch/mips/boot/start.S
> index c1cd2d9dd5..95b6596dde 100644
> --- a/arch/mips/boot/start.S
> +++ b/arch/mips/boot/start.S
> @@ -34,7 +34,7 @@ EXPORT(_start)
>          move    a0, s0
>          move    a1, s1
>          move    a2, s2
> -       la      v0, relocate_code
> +       la      v0, main_entry
>          jal     v0
>           nop
> 
> 
> Additional testing on real hardware has to be done.
> 

Kind regards,
Oleksij Rempel

-- 
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