tile: map data region shadow of kernel as R/W

This is necessary for things like reading /proc/kcore, doing ftrace, etc. It happens by default when using huge pages to map the kernel data, but not when using small pages. Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>

tile: map data region shadow of kernel as R/W
This is necessary for things like reading /proc/kcore, doing ftrace, etc. It happens by default when using huge pages to map the kernel data, but not when using small pages. Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
Chris Metcalf
1 parent 49e4e15619
Showing 1 changed file with 5 additions and 2 deletions Side-by-side Diff
arch/tile/mm/init.c
@@ -233,9 +233,12 @@
 	if (kdata_huge)
 		return construct_pgprot(PAGE_KERNEL, PAGE_HOME_HASH);
  
-	/* We map the aliased pages of permanent text inaccessible. */
+	/*
+	 * We map the aliased pages of permanent text so we can
+	 * update them if necessary, for ftrace, etc.
+	 */
 	if (address < (ulong) _sinittext - CODE_DELTA)
-		return PAGE_NONE;
+		return construct_pgprot(PAGE_KERNEL, PAGE_HOME_HASH);
  
 	/* We map read-only data non-coherent for performance. */
 	if ((address >= (ulong) __start_rodata &&
...	...	@@ -233,9 +233,12 @@
233	233	if (kdata_huge)
234	234	return construct_pgprot(PAGE_KERNEL, PAGE_HOME_HASH);
235	235
236		- /* We map the aliased pages of permanent text inaccessible. */
	236	+ /*
	237	+ * We map the aliased pages of permanent text so we can
	238	+ * update them if necessary, for ftrace, etc.
	239	+ */
237	240	if (address < (ulong) _sinittext - CODE_DELTA)
238		- return PAGE_NONE;
	241	+ return construct_pgprot(PAGE_KERNEL, PAGE_HOME_HASH);
239	242
240	243	/* We map read-only data non-coherent for performance. */
241	244	if ((address >= (ulong) __start_rodata &&