dma/pool: Ensure DMA_DIRECT_REMAP allocations are decrypted

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

diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c
index 7b04f7575796b8f3a4bd29ac39f56f1e2f07168f..ee45dee33d4916b7d7bd837bc4409f7762f8cc1d 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