Revert "remoteproc: qcom_q6v5_mss: map/unmap metadata region before/after use"

This reverts commit fc156629b23a21181e473e60341e3a78af25a1d4.

This commit manages to do three API violations at once:

 - dereference the return value of dma_alloc_attrs with the
   DMA_ATTR_NO_KERNEL_MAPPING mapping, which is clearly forbidden and
   will do the wrong thing on various dma mapping implementations.  The
   fact that dma-direct uses a struct page as a cookie is an undocumented
   implementation detail
 - include dma-map-ops.h and use pgprot_dmacoherent despite a clear
   comment documenting that this is not acceptable
 - use of the VM_DMA_COHERENT for something that is not the dma-mapping
   code
 - use of VM_FLUSH_RESET_PERMS for vmap, while it is only supported for
   vmalloc

Acked-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sibi Sankar <quic_sibis@quicinc.com>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230117085840.32356-6-quic_sibis@quicinc.com

diff --git a/drivers/remoteproc/qcom_q6v5_mss.c b/drivers/remoteproc/qcom_q6v5_mss.c
index 2f40276..e2f765f 100644 (file)
--- a/drivers/remoteproc/qcom_q6v5_mss.c
+++ b/drivers/remoteproc/qcom_q6v5_mss.c
@@ -10,7 +10,6 @@
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/devcoredump.h>
-#include <linux/dma-map-ops.h>
 #include <linux/dma-mapping.h>
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
@@ -961,52 +960,27 @@ static void q6v5proc_halt_axi_port(struct q6v5 *qproc,
 static int q6v5_mpss_init_image(struct q6v5 *qproc, const struct firmware *fw,
                                const char *fw_name)
 {
-       unsigned long dma_attrs = DMA_ATTR_FORCE_CONTIGUOUS | DMA_ATTR_NO_KERNEL_MAPPING;
-       unsigned long flags = VM_DMA_COHERENT | VM_FLUSH_RESET_PERMS;
-       struct page **pages;
-       struct page *page;
+       unsigned long dma_attrs = DMA_ATTR_FORCE_CONTIGUOUS;
        dma_addr_t phys;
        void *metadata;
        int mdata_perm;
        int xferop_ret;
        size_t size;
-       void *vaddr;
-       int count;
+       void *ptr;
        int ret;
-       int i;
 
        metadata = qcom_mdt_read_metadata(fw, &size, fw_name, qproc->dev);
        if (IS_ERR(metadata))
                return PTR_ERR(metadata);
 
-       page = dma_alloc_attrs(qproc->dev, size, &phys, GFP_KERNEL, dma_attrs);
-       if (!page) {
+       ptr = dma_alloc_attrs(qproc->dev, size, &phys, GFP_KERNEL, dma_attrs);
+       if (!ptr) {
                kfree(metadata);
                dev_err(qproc->dev, "failed to allocate mdt buffer\n");
                return -ENOMEM;
        }
 
-       count = PAGE_ALIGN(size) >> PAGE_SHIFT;
-       pages = kmalloc_array(count, sizeof(struct page *), GFP_KERNEL);
-       if (!pages) {
-               ret = -ENOMEM;
-               goto free_dma_attrs;
-       }
-
-       for (i = 0; i < count; i++)
-               pages[i] = nth_page(page, i);
-
-       vaddr = vmap(pages, count, flags, pgprot_dmacoherent(PAGE_KERNEL));
-       kfree(pages);
-       if (!vaddr) {
-               dev_err(qproc->dev, "unable to map memory region: %pa+%zx\n", &phys, size);
-               ret = -EBUSY;
-               goto free_dma_attrs;
-       }
-
-       memcpy(vaddr, metadata, size);
-
-       vunmap(vaddr);
+       memcpy(ptr, metadata, size);
 
        /* Hypervisor mapping to access metadata by modem */
        mdata_perm = BIT(QCOM_SCM_VMID_HLOS);
@@ -1036,7 +1010,7 @@ static int q6v5_mpss_init_image(struct q6v5 *qproc, const struct firmware *fw,
                         "mdt buffer not reclaimed system may become unstable\n");
 
 free_dma_attrs:
-       dma_free_attrs(qproc->dev, size, page, phys, dma_attrs);
+       dma_free_attrs(qproc->dev, size, ptr, phys, dma_attrs);
        kfree(metadata);
 
        return ret < 0 ? ret : 0;