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1f9677582a
Currently, platforms do not provide complete memory region information to OpenSBI. Generally, memory regions are only created for the few MMIO devices that have M-mode drivers. As a result, most MMIO devices fall inside the default S-mode RWX memory region, which does _not_ have the MMIO flag set. In fact, OpenSBI relies on certain S-mode MMIO devices being inside non-MMIO memory regions. Both fdt_domain_based_fixup_one() and mpxy_rpmi_sysmis_xfer() call sbi_domain_check_addr() with the MMIO flag cleared, and that function currently requires an exact flag match. Those access checks will thus erroneously fail if the platform creates memory regions with the correct flags for these devices (or for a larger MMIO region containing these devices). We should not ignore the MMIO flag entirely, because sbi_domain_check_addr() is also used to check the permissions of S-mode shared memory buffers, and S-mode should not be using MMIO device addresses as memory buffers. But when checking if S-mode is allowed to do MMIO accesses, we need to recognize that MMIO devices appear in memory regions both with and without the MMIO flag set. Signed-off-by: Samuel Holland <samuel.holland@sifive.com> Reviewed-by: Yu-Chien Peter Lin <peter.lin@sifive.com> Reviewed-by: Anup Patel <anup@brainfault.org> Link: https://lore.kernel.org/r/20251121193808.1528050-2-samuel.holland@sifive.com Signed-off-by: Anup Patel <anup@brainfault.org>