[PATCH 3/4] [mm/nommu]: use copy_to_user_page to call flush icache for [#811] toolchain old bug

[Bryan Wu]

From: Jie Zhang <jie.zhang@xxxxxxxxxx>

access_process_vm in mm/memory.c uses copy_to_user_page and
copy_from_user_page. So for !MMU we'd better do the same thing.
Other archs with mmu do the cache flush in copy_to_user_page.
It gives me hint that copy_to_user_page is designed to flush
the cache. On other side, no archs do the cache flush ptrace.

Signed-off-by: Jie Zhang <jie.zhang@xxxxxxxxxx>
Signed-off-by: Bryan Wu <cooloney@xxxxxxxxxx>
---
 mm/nommu.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/mm/nommu.c b/mm/nommu.c
index c11e5cc..56bb447 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1458,9 +1458,11 @@ int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, in
 
 		/* only read or write mappings where it is permitted */
 		if (write && vma->vm_flags & VM_MAYWRITE)
-			len -= copy_to_user((void *) addr, buf, len);
+			copy_to_user_page(vma, NULL, NULL,
+					  (void *) addr, buf, len);
 		else if (!write && vma->vm_flags & VM_MAYREAD)
-			len -= copy_from_user(buf, (void *) addr, len);
+			copy_from_user_page(vma, NULL, NULL,
+					    buf, (void *) addr, len);
 		else
 			len = 0;
 	} else {
-- 
1.5.5

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