dma/pool: Ensure DMA_DIRECT_REMAP allocations are decrypted

commit 89a2d212bdb4bc29bed8e7077abe054b801137ea upstream.

When CONFIG_DMA_DIRECT_REMAP is enabled, atomic pool pages are
remapped via dma_common_contiguous_remap() using the supplied
pgprot. Currently, the mapping uses
pgprot_dmacoherent(PAGE_KERNEL), which leaves the memory encrypted
on systems with memory encryption enabled (e.g., ARM CCA Realms).

This can cause the DMA layer to fail or crash when accessing the
memory, as the underlying physical pages are not configured as
expected.

Fix this by requesting a decrypted mapping in the vmap() call:
pgprot_decrypted(pgprot_dmacoherent(PAGE_KERNEL))

This ensures that atomic pool memory is consistently mapped
unencrypted.

Cc: stable@vger.kernel.org
Signed-off-by: Shanker Donthineni <sdonthineni@nvidia.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20250811181759.998805-1-sdonthineni@nvidia.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c
index b481c48a31a630284f9c32d94213a210ea792334..6b0be9598a973f92078a6047c399f1383886ca34 100644 (file)
--- a/kernel/dma/pool.c
+++ b/kernel/dma/pool.c
@@ -102,8 +102,8 @@ static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size,
 
 #ifdef CONFIG_DMA_DIRECT_REMAP
        addr = dma_common_contiguous_remap(page, pool_size,
-                                          pgprot_dmacoherent(PAGE_KERNEL),
-                                          __builtin_return_address(0));
+                       pgprot_decrypted(pgprot_dmacoherent(PAGE_KERNEL)),
+                       __builtin_return_address(0));
        if (!addr)
                goto free_page;
 #else