This is same as the generic code, but then we have to duplicate
because we need to enable enable this along with hash which set
HAVE_ARCH_UNMAPPED_AREA. Hash need special get_unmapped_area handling
because of limitations around base page size. With radix we don't have
such restrictions.
Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.vnet.ibm.com>
---
arch/powerpc/mm/mmap.c | 109 +++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 109 insertions(+)
diff --git a/arch/powerpc/mm/mmap.c b/arch/powerpc/mm/mmap.c
index 0f0502e12f6c..001997c7299b 100644
--- a/arch/powerpc/mm/mmap.c
+++ b/arch/powerpc/mm/mmap.c
@@ -26,6 +26,8 @@
#include <linux/mm.h>
#include <linux/random.h>
#include <linux/sched.h>
+#include <linux/security.h>
+#include <linux/mman.h>
/*
* Top of mmap area (just below the process stack).
@@ -78,6 +80,111 @@ static inline unsigned long mmap_base(unsigned long rnd)
return PAGE_ALIGN(TASK_SIZE - gap - rnd);
}
+#ifdef CONFIG_PPC_RADIX_MMU
+/*
+ * Same function as generic code used only for radix, because we don't need to
overload
+ * the generic one. But we will have to duplicate, because hash select
+ * HAVE_ARCH_UNMAPPED_AREA
+ */
+static unsigned long
+arch_radix_get_unmapped_area(struct file *filp, unsigned long addr,
+ unsigned long len, unsigned long pgoff,
+ unsigned long flags)
+{
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma;
+ struct vm_unmapped_area_info info;
+
+ if (len > TASK_SIZE - mmap_min_addr)
+ return -ENOMEM;
+
+ if (flags & MAP_FIXED)
+ return addr;
+
+ if (addr) {
+ addr = PAGE_ALIGN(addr);
+ vma = find_vma(mm, addr);
+ if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
+ (!vma || addr + len <= vma->vm_start))
+ return addr;
+ }
+
+ info.flags = 0;
+ info.length = len;
+ info.low_limit = mm->mmap_base;
+ info.high_limit = TASK_SIZE;
+ info.align_mask = 0;
+ return vm_unmapped_area(&info);
+}
+
+static unsigned long
+arch_radix_get_unmapped_area_topdown(struct file *filp,
+ const unsigned long addr0,
+ const unsigned long len,
+ const unsigned long pgoff,
+ const unsigned long flags)
+{
+ struct vm_area_struct *vma;
+ struct mm_struct *mm = current->mm;
+ unsigned long addr = addr0;
+ struct vm_unmapped_area_info info;
+
+ /* requested length too big for entire address space */
+ if (len > TASK_SIZE - mmap_min_addr)
+ return -ENOMEM;
+
+ if (flags & MAP_FIXED)
+ return addr;
+
+ /* requesting a specific address */
+ if (addr) {
+ addr = PAGE_ALIGN(addr);
+ vma = find_vma(mm, addr);
+ if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
+ (!vma || addr + len <= vma->vm_start))
+ return addr;
+ }
+
+ info.flags = VM_UNMAPPED_AREA_TOPDOWN;
+ info.length = len;
+ info.low_limit = max(PAGE_SIZE, mmap_min_addr);
+ info.high_limit = mm->mmap_base;
+ info.align_mask = 0;
+ addr = vm_unmapped_area(&info);
+
+ /*
+ * A failed mmap() very likely causes application failure,
+ * so fall back to the bottom-up function here. This scenario
+ * can happen with large stack limits and large mmap()
+ * allocations.
+ */
+ if (addr & ~PAGE_MASK) {
+ VM_BUG_ON(addr != -ENOMEM);
+ info.flags = 0;
+ info.low_limit = TASK_UNMAPPED_BASE;
+ info.high_limit = TASK_SIZE;
+ addr = vm_unmapped_area(&info);
+ }
+
+ return addr;
+}
+
+static void arch_pick_radix_mmap_layout(struct mm_struct *mm,
+ unsigned long random_factor)
+{
+ if (mmap_is_legacy()) {
+ mm->mmap_base = TASK_UNMAPPED_BASE;
+ mm->get_unmapped_area = arch_radix_get_unmapped_area;
+ } else {
+ mm->mmap_base = mmap_base(random_factor);
+ mm->get_unmapped_area = arch_radix_get_unmapped_area_topdown;
+ }
+}
+#else
+/* dummy */
+extern void arch_pick_radix_mmap_layout(struct mm_struct *mm,
+ unsigned long random_factor);
+#endif
/*
* This function, called very early during the creation of a new
* process VM image, sets up which VM layout function to use:
@@ -89,6 +196,8 @@ void arch_pick_mmap_layout(struct mm_struct *mm)
if (current->flags & PF_RANDOMIZE)
random_factor = arch_mmap_rnd();
+ if (radix_enabled())
+ return arch_pick_radix_mmap_layout(mm, random_factor);
/*
* Fall back to the standard layout if the personality
* bit is set, or if the expected stack growth is unlimited:
--
2.5.0
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