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| author | David Rientjes <rientjes@google.com> | 2020-04-14 17:04:58 -0700 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2020-04-25 13:17:05 +0200 |
| commit | 76a19940bd62a81148c303f3df6d0cee9ae4b509 (patch) | |
| tree | 71caddd9ff61acea7bb981c723e33575278431c4 /kernel/dma/pool.c | |
| parent | 54adadf9b08571fb8b11dc9d0d3a2ddd39825efd (diff) | |
| download | linux-76a19940bd62a81148c303f3df6d0cee9ae4b509.tar.gz linux-76a19940bd62a81148c303f3df6d0cee9ae4b509.tar.bz2 linux-76a19940bd62a81148c303f3df6d0cee9ae4b509.zip | |
dma-direct: atomic allocations must come from atomic coherent pools
When a device requires unencrypted memory and the context does not allow
blocking, memory must be returned from the atomic coherent pools.
This avoids the remap when CONFIG_DMA_DIRECT_REMAP is not enabled and the
config only requires CONFIG_DMA_COHERENT_POOL. This will be used for
CONFIG_AMD_MEM_ENCRYPT in a subsequent patch.
Keep all memory in these pools unencrypted. When set_memory_decrypted()
fails, this prohibits the memory from being added. If adding memory to
the genpool fails, and set_memory_encrypted() subsequently fails, there
is no alternative other than leaking the memory.
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'kernel/dma/pool.c')
| -rw-r--r-- | kernel/dma/pool.c | 27 |
1 files changed, 24 insertions, 3 deletions
diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c index ffe866c2c034..c8d61b3a7bd6 100644 --- a/kernel/dma/pool.c +++ b/kernel/dma/pool.c @@ -8,6 +8,7 @@ #include <linux/dma-contiguous.h> #include <linux/init.h> #include <linux/genalloc.h> +#include <linux/set_memory.h> #include <linux/slab.h> #include <linux/workqueue.h> @@ -53,22 +54,42 @@ static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size, arch_dma_prep_coherent(page, pool_size); +#ifdef CONFIG_DMA_DIRECT_REMAP addr = dma_common_contiguous_remap(page, pool_size, pgprot_dmacoherent(PAGE_KERNEL), __builtin_return_address(0)); if (!addr) goto free_page; - +#else + addr = page_to_virt(page); +#endif + /* + * Memory in the atomic DMA pools must be unencrypted, the pools do not + * shrink so no re-encryption occurs in dma_direct_free_pages(). + */ + ret = set_memory_decrypted((unsigned long)page_to_virt(page), + 1 << order); + if (ret) + goto remove_mapping; ret = gen_pool_add_virt(pool, (unsigned long)addr, page_to_phys(page), pool_size, NUMA_NO_NODE); if (ret) - goto remove_mapping; + goto encrypt_mapping; return 0; +encrypt_mapping: + ret = set_memory_encrypted((unsigned long)page_to_virt(page), + 1 << order); + if (WARN_ON_ONCE(ret)) { + /* Decrypt succeeded but encrypt failed, purposely leak */ + goto out; + } remove_mapping: +#ifdef CONFIG_DMA_DIRECT_REMAP dma_common_free_remap(addr, pool_size); -free_page: +#endif +free_page: __maybe_unused if (!dma_release_from_contiguous(NULL, page, 1 << order)) __free_pages(page, order); out: |