[SPARC64]: Top-down address space allocation for 32-bit tasks.
Currently allocations are very constrained for 32-bit processes.
It grows down-up from 0x70000000 to 0xf0000000 which gives about
2GB of stack + dynamic mmap() space.
So support the top-down method, and we need to override the
generic helper function in order to deal with D-cache coloring.
With these changes I was able to squeeze out a mmap() just over
3.6GB in size in a 32-bit process.
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/asm-sparc64/pgtable.h b/include/asm-sparc64/pgtable.h
index d427ce6..ed4124e 100644
--- a/include/asm-sparc64/pgtable.h
+++ b/include/asm-sparc64/pgtable.h
@@ -752,8 +752,11 @@
#include <asm-generic/pgtable.h>
-/* We provide our own get_unmapped_area to cope with VA holes for userland */
+/* We provide our own get_unmapped_area to cope with VA holes and
+ * SHM area cache aliasing for userland.
+ */
#define HAVE_ARCH_UNMAPPED_AREA
+#define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
/* We provide a special get_unmapped_area for framebuffer mmaps to try and use
* the largest alignment possible such that larget PTEs can be used.