[PATCH] flexible-mmap for ppc64

From: <arjanv@redhat.com>

Implement the new address space layout for 32-bit apps running on ppc64.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/arch/ppc64/mm/Makefile b/arch/ppc64/mm/Makefile
index 4e47f66faa0d14056f0803d1277a39bfb66b1c36..d63dc4421f39a41d567c416a044a0880ce7a2d77 100644 (file)
--- a/arch/ppc64/mm/Makefile
+++ b/arch/ppc64/mm/Makefile
@@ -5,6 +5,6 @@
 EXTRA_CFLAGS += -mno-minimal-toc
 
 obj-y := fault.o init.o imalloc.o hash_utils.o hash_low.o tlb.o \
-       slb_low.o slb.o stab.o
+       slb_low.o slb.o stab.o mmap.o
 obj-$(CONFIG_DISCONTIGMEM) += numa.o
 obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o

diff --git a/arch/ppc64/mm/mmap.c b/arch/ppc64/mm/mmap.c
new file mode 100644 (file)
index 0000000..f90dd1f
--- /dev/null
+++ b/arch/ppc64/mm/mmap.c
@@ -0,0 +1,86 @@
+/*
+ *  linux/arch/ppc64/mm/mmap.c
+ *
+ *  flexible mmap layout support
+ *
+ * Copyright 2003-2004 Red Hat Inc., Durham, North Carolina.
+ * All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ *
+ * Started by Ingo Molnar <mingo@elte.hu>
+ */
+
+#include <linux/personality.h>
+#include <linux/mm.h>
+
+/*
+ * Top of mmap area (just below the process stack).
+ *
+ * Leave an at least ~128 MB hole.
+ */
+#define MIN_GAP (128*1024*1024)
+#define MAX_GAP (TASK_SIZE/6*5)
+
+static inline unsigned long mmap_base(void)
+{
+       unsigned long gap = current->rlim[RLIMIT_STACK].rlim_cur;
+
+       if (gap < MIN_GAP)
+               gap = MIN_GAP;
+       else if (gap > MAX_GAP)
+               gap = MAX_GAP;
+
+       return TASK_SIZE - (gap & PAGE_MASK);
+}
+
+static inline int mmap_is_legacy(void)
+{
+       /*
+        * Force standard allocation for 64 bit programs.
+        */
+       if (!test_thread_flag(TIF_32BIT))
+               return 1;
+
+       if (current->personality & ADDR_COMPAT_LAYOUT)
+               return 1;
+
+       if (current->rlim[RLIMIT_STACK].rlim_cur == RLIM_INFINITY)
+               return 1;
+
+       return sysctl_legacy_va_layout;
+}
+
+/*
+ * This function, called very early during the creation of a new
+ * process VM image, sets up which VM layout function to use:
+ */
+void arch_pick_mmap_layout(struct mm_struct *mm)
+{
+       /*
+        * Fall back to the standard layout if the personality
+        * bit is set, or if the expected stack growth is unlimited:
+        */
+       if (mmap_is_legacy()) {
+               mm->mmap_base = TASK_UNMAPPED_BASE;
+               mm->get_unmapped_area = arch_get_unmapped_area;
+               mm->unmap_area = arch_unmap_area;
+       } else {
+               mm->mmap_base = mmap_base();
+               mm->get_unmapped_area = arch_get_unmapped_area_topdown;
+               mm->unmap_area = arch_unmap_area_topdown;
+       }
+}

diff --git a/include/asm-ppc64/processor.h b/include/asm-ppc64/processor.h
index 7f8884145ff1d4162ea39cb9896a6c8738338001..b8e80dfc96f303032d049fd5bac6641dfff90ac5 100644 (file)
--- a/include/asm-ppc64/processor.h
+++ b/include/asm-ppc64/processor.h
@@ -628,6 +628,8 @@ static inline void prefetchw(const void *x)
 
 #endif /* ASSEMBLY */
 
+#define HAVE_ARCH_PICK_MMAP_LAYOUT
+
 /*
  * Number of entries in the SLB. If this ever changes we should handle
  * it with a use a cpu feature fixup.