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Linghui Wu
4f25071afe
On WCN3990/SNOC the MSA region is mapped with devm_memremap(MEMREMAP_WT).
On arm64 such a mapping is not Normal-cacheable, so unaligned accesses to
it are not permitted. ath10k_msa_dump_memory() copies the region with a
plain memcpy(), whose optimized __pi_memcpy_generic implementation issues
wide/unaligned loads. This triggers an alignment fault (FSC=0x21) Oops in
ath10k_snoc_fw_crashed_dump() while collecting the devcoredump:
Unable to handle kernel paging request ... FSC=0x21: alignment fault
pc : __pi_memcpy_generic
lr : ath10k_snoc_fw_crashed_dump [ath10k_snoc]
The Oops both leaves the firmware RAM dump buffer zeroed (no dump is
captured) and crashes the kernel, which in turn breaks modem SSR
recovery.
Use memcpy_fromio(), which only performs accesses that are valid for such
a device-memory mapping. The generic memcpy_fromio() implementation aligns
the source before issuing word-sized reads and stores the destination with
put_unaligned(), so it is also safe for the coherent DMA allocation used on
the non-reserved-memory path. ath11k and ath12k use the same pattern
when copying target memory into crash dumps, so call it unconditionally
here too.
The MEMREMAP_WT pointer is a plain void *, so an explicit __iomem cast is
needed; use __force to keep sparse happy.
Tested-on: WCN3990 hw1.0 SNOC WLAN.HL.3.3.7.c5-00107-QCAHLSWMTPL-1
Fixes: 3f14b73c38 ("ath10k: Enable MSA region dump support for WCN3990")
Signed-off-by: Linghui Wu <linghui.wu@oss.qualcomm.com>
Reviewed-by: Rameshkumar Sundaram <rameshkumar.sundaram@oss.qualcomm.com>
Reviewed-by: Baochen Qiang <baochen.qiang@oss.qualcomm.com>
Link: https://patch.msgid.link/20260727072629.2297208-1-linghui.wu@oss.qualcomm.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>
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