[PATCH v1 4/4] arm64: dts: qcom: sm8750: Make the ADSP remote heap no-map

[Jianping Li]

The ADSP remote heap is declared as a reusable shared DMA pool.
Allowing the kernel to reuse this region is incompatible with handing
the entire region over to the DSP, as HLOS allocations may access
pages for which HLOS no longer has access permissions.

The same configuration has caused synchronous external aborts on
other platforms when the kernel accesses pages within the ADSP remote
heap.

Replace reusable with no-map to keep the region reserved for the DSP
and exclude it from the kernel's standard memory mapping.

Fixes: 0bcf9ca23a873 ("arm64: dts: qcom: sm8750: add memory node for adsp fastrpc")
Link: https://lore.kernel.org/all/20251209-sm8750-fastrpc-adsp-v3-1-ccfff49a8af9@xxxxxxxxxx/
Signed-off-by: Jianping Li <jianping.li@xxxxxxxxxxxxxxxx>
---
 arch/arm64/boot/dts/qcom/sm8750.dtsi | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/boot/dts/qcom/sm8750.dtsi b/arch/arm64/boot/dts/qcom/sm8750.dtsi
index cf947acc5760..0d493359408b 100644
--- a/arch/arm64/boot/dts/qcom/sm8750.dtsi
+++ b/arch/arm64/boot/dts/qcom/sm8750.dtsi
@@ -561,7 +561,7 @@ adsp_rpc_remote_heap_mem: adsp-rpc-remote-heap {
 			alloc-ranges = <0x0 0x00000000 0x0 0xffffffff>;
 			alignment = <0x0 0x400000>;
 			size = <0x0 0xc00000>;
-			reusable;
+			no-map;
 		};
 	};
 
-- 
2.43.0