[RESEND][PATCH] DSPBRIDGE: cache operation against kernel address instead of user's

[Omar Ramirez Luna]

From: Hiroshi DOYU <hiroshi.d...@nokia.com>

Based on the discussion:
  http://www.spinics.net/lists/arm-kernel/msg72810.html
HACK: export "follow_page()" for dspbridge cache operation

Signed-off-by: Hiroshi DOYU <hiroshi.d...@nokia.com>
---
 drivers/dsp/bridge/rmgr/proc.c |   68 
++++++++++++++++++++++++++++++---------
 mm/memory.c                    |    1 +
 2 files changed, 53 insertions(+), 16 deletions(-)

diff --git a/drivers/dsp/bridge/rmgr/proc.c b/drivers/dsp/bridge/rmgr/proc.c
index 491661f..3e05281 100644
--- a/drivers/dsp/bridge/rmgr/proc.c
+++ b/drivers/dsp/bridge/rmgr/proc.c
@@ -574,8 +574,43 @@ DSP_STATUS PROC_EnumNodes(DSP_HPROCESSOR 
hProcessor, OUT DSP_HNODE *aNodeTab,
        return status;
 }

+/* Cache operation against kernel address instead of users */
+static int memory_sync_page(struct vm_area_struct *vma, unsigned long 
start,
+                           ssize_t len, enum DSP_FLUSHTYPE ftype)
+{
+       struct page *page;
+       void *kaddr;
+       unsigned long offset;
+       ssize_t rest;
+
+       while (len) {
+               page = follow_page(vma, start, FOLL_GET);
+               if (!page) {
+                       pr_err("%s: no page for %08lx\n", __func__, start);
+                       return -EINVAL;
+               } else if (IS_ERR(page)) {
+                       pr_err("%s: err page for %08lx(%lu)\n", __func__, start,
+                              IS_ERR(page));
+                       return IS_ERR(page);
+               }
+
+               offset = start & ~PAGE_MASK;
+               kaddr = page_address(page) + offset;
+               rest = min_t(ssize_t, PAGE_SIZE - offset, len);
+
+               MEM_FlushCache(kaddr, rest, ftype);
+
+               put_page(page);
+               len -= rest;
+               start += rest;
+       }
+
+       return 0;
+}
+
 /* Check if the given area blongs to process virtul memory address 
space */
-static int memory_check_vma(unsigned long start, u32 len)
+static int memory_sync_vma(unsigned long start, u32 len,
+                          enum DSP_FLUSHTYPE ftype)
 {
        int err = 0;
        unsigned long end;
@@ -585,14 +620,19 @@ static int memory_check_vma(unsigned long start, 
u32 len)
        if (end <= start)
                return -EINVAL;

-       down_read(&current->mm->mmap_sem);
-
        while ((vma = find_vma(current->mm, start)) != NULL) {
+               ssize_t size;

-               if (vma->vm_start > start) {
-                       err = -EINVAL;
+               if (vma->vm_flags & (VM_IO | VM_PFNMAP))
+                       return -EINVAL;
+
+               if (vma->vm_start > start)
+                       return -EINVAL;
+
+               size = min_t(ssize_t, vma->vm_end - start, len);
+               err = memory_sync_page(vma, start, size, ftype);
+               if (err)
                        break;
-               }

                if (end <= vma->vm_end)
                        break;
@@ -603,8 +643,6 @@ static int memory_check_vma(unsigned long start, u32 
len)
        if (!vma)
                err = -EINVAL;

-       up_read(&current->mm->mmap_sem);
-
        return err;
 }

@@ -629,17 +667,15 @@ static DSP_STATUS proc_memory_sync(DSP_HPROCESSOR 
hProcessor, void *pMpuAddr,
                goto err_out;
        }

-       if (memory_check_vma((u32)pMpuAddr, ulSize)) {
-               GT_3trace(PROC_DebugMask, GT_7CLASS,
-                         "%s: InValid address parameters\n",
-                         __func__, pMpuAddr, ulSize);
+       down_read(&current->mm->mmap_sem);
+
+       if (memory_sync_vma((u32)pMpuAddr, ulSize, FlushMemType)) {
+               pr_err("%s: InValid address parameters %p %x\n",
+                      __func__, pMpuAddr, ulSize);
                status = DSP_EHANDLE;
-               goto err_out;
        }

-       (void)SYNC_EnterCS(hProcLock);
-       MEM_FlushCache(pMpuAddr, ulSize, FlushMemType);
-       (void)SYNC_LeaveCS(hProcLock);
+       up_read(&current->mm->mmap_sem);

 err_out:
        GT_2trace(PROC_DebugMask, GT_ENTER,
diff --git a/mm/memory.c b/mm/memory.c
index 6ab19dd..377be88 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1228,6 +1228,7 @@ no_page_table:
                return ERR_PTR(-EFAULT);
        return page;
 }
+EXPORT_SYMBOL_GPL(follow_page);

 int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
                     unsigned long start, int nr_pages, unsigned int gup_flags,
--
1.6.2.4


--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html