Re: [PATCH v6 04/11] arm64: dts: ti: k3-am62p-verdin: Fix wkup R5F memory region size

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Unaligned `no-map` memory region breaks semantics on 64KB-page ARM64 kernels, exposing firmware memory to speculative accesses and corruption.
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commit 7feed923de4c5fff1956c33a3b2895b2571326ee
Author: Markus Schneider-Pargmann (TI) <msp@baylibre.com>

arm64: dts: ti: k3-am62p-verdin: Fix wkup R5F memory region size

This commit updates the wkup R5F memory region to match the MCU SDK linker
footprint.

Link: https://github.com/TexasInstruments/mcupsdk-core-k3/blob/k3_main/examples/drivers/ipc/ipc_rpmsg_echo_linux/am62px-sk/wkup-r5fss0-0_freertos/ti-arm-clang/linker.cmd

> diff --git a/arch/arm64/boot/dts/ti/k3-am62p-verdin.dtsi b/arch/arm64/boot/dts/ti/k3-am62p-verdin.dtsi
> --- a/arch/arm64/boot/dts/ti/k3-am62p-verdin.dtsi
> +++ b/arch/arm64/boot/dts/ti/k3-am62p-verdin.dtsi
> @@ -170,7 +170,7 @@ wkup_r5fss0_core0_dma_memory_region: memory@9c800000 {
>  
>  		wkup_r5fss0_core0_memory_region: memory@9c900000 {
>  			compatible = "shared-dma-pool";
> -			reg = <0x00 0x9c900000 0x00 0x01e00000>;
> +			reg = <0x00 0x9c900000 0x00 0x01d08000>;

[Severity: High]
The new size 0x01d08000 applied to 0x9c900000 creates an end address of
0x9e608000. Does this unaligned end address cause mapping issues on
64kb-page arm64 kernels?

When the memory mapping logic processes adjacent valid memory starting at
0x9e608000, won't __create_pgd_mapping_locked() round the start address
down to the page boundary at 0x9e600000?

It seems this would inadvertently map the last 32kb of the no-map firmware
region (0x9e600000 to 0x9e608000) into the linear map as normal cacheable
memory. Could this mismatched memory attribute and speculative cache eviction
corrupt remote processor data?

I also noticed that later patches in the series move and split this region,
but they appear to retain the unaligned 0x9e608000 end address in
wkup_r5fss0_core0_dm_region. Will the alignment issue persist through the
end of the series?

>  			no-map;
>  		};
>  	};

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Sashiko AI review · https://sashiko.dev/#/patchset/20260609-topic-am62a-ioddr-dt-v6-19-v6-0-16afba97fbe0@baylibre.com?part=4