ARC: add configuration option for MMU page size

ARC CPU may have MMU page size of 4/8(default)/16k.
uClibc needs to have page size configured accodring to HW it will be run on.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

extra/Configs/Config.arc

@@ -21,3 +21,20 @@ config CONFIG_ARC_CPU_700
 	  ARCompact ISA based ARC CPU
 
 endchoice
+
+choice
+	prompt "MMU Page Size"
+	default CONFIG_ARC_PAGE_SIZE_8K
+
+config CONFIG_ARC_PAGE_SIZE_8K
+	bool "8KB"
+	help
+	  Choose between 4k, 8k (default) or 16k
+
+config CONFIG_ARC_PAGE_SIZE_16K
+	bool "16KB"
+
+config CONFIG_ARC_PAGE_SIZE_4K
+	bool "4KB"
+
+endchoice

libc/sysdeps/linux/arc/bits/uClibc_page.h

@@ -9,16 +9,25 @@
 
 /*
  * ARC700/linux supports 4k, 8k, 16k pages (build time).
- * We rely on the kernel exported header (aka uapi headers since 3.8)
- * for PAGE_SIZE and friends. This avoids hand-editing here when building
- * toolchain.
  *
  * Although uClibc determines page size dynamically, from kernel's auxv which
  * ARC Linux does pass, still the generic code needs a fall back
  *  _dl_pagesize = auxvt[AT_PAGESZ].a_un.a_val ? : PAGE_SIZE
  *
  */
-#include <asm/page.h>
+
+#include <features.h>
+
+#if defined(__CONFIG_ARC_PAGE_SIZE_16K__)
+#define PAGE_SHIFT		14
+#elif defined(__CONFIG_ARC_PAGE_SIZE_4K__)
+#define PAGE_SHIFT		12
+#else
+#define PAGE_SHIFT		13
+#endif
+
+#define PAGE_SIZE	(1UL << PAGE_SHIFT)
+#define PAGE_MASK	(~(PAGE_SIZE-1))
 
 /* TBD: fix this with runtime value for a PAGE_SIZE agnostic uClibc */
 #define MMAP2_PAGE_SHIFT PAGE_SHIFT