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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2015-01-14 17:51:17 +0100
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2015-01-22 12:15:59 +0100
commit1f6b83e5e4d3aed46eac1d219322fba9c7341cd8 (patch)
treea7839cd769ec8637746d5e20a7eb7117373caaf0 /arch/s390/mm/mmap.c
parentf8b2dcbd9e6d1479b9b5a9e9e78bbaf783bde819 (diff)
downloadlinux-1f6b83e5e4d3aed46eac1d219322fba9c7341cd8.tar.bz2
s390: avoid z13 cache aliasing
Avoid cache aliasing on z13 by aligning shared objects to multiples of 512K. The virtual addresses of a page from a shared file needs to have identical bits in the range 2^12 to 2^18. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/mm/mmap.c')
-rw-r--r--arch/s390/mm/mmap.c142
1 files changed, 140 insertions, 2 deletions
diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c
index 9b436c21195e..d008f638b2cd 100644
--- a/arch/s390/mm/mmap.c
+++ b/arch/s390/mm/mmap.c
@@ -28,8 +28,12 @@
#include <linux/module.h>
#include <linux/random.h>
#include <linux/compat.h>
+#include <linux/security.h>
#include <asm/pgalloc.h>
+unsigned long mmap_rnd_mask;
+unsigned long mmap_align_mask;
+
static unsigned long stack_maxrandom_size(void)
{
if (!(current->flags & PF_RANDOMIZE))
@@ -60,8 +64,10 @@ static unsigned long mmap_rnd(void)
{
if (!(current->flags & PF_RANDOMIZE))
return 0;
- /* 8MB randomization for mmap_base */
- return (get_random_int() & 0x7ffUL) << PAGE_SHIFT;
+ if (is_32bit_task())
+ return (get_random_int() & 0x7ff) << PAGE_SHIFT;
+ else
+ return (get_random_int() & mmap_rnd_mask) << PAGE_SHIFT;
}
static unsigned long mmap_base_legacy(void)
@@ -81,6 +87,106 @@ static inline unsigned long mmap_base(void)
return STACK_TOP - stack_maxrandom_size() - mmap_rnd() - gap;
}
+unsigned long
+arch_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;
+ int do_color_align;
+
+ 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;
+ }
+
+ do_color_align = 0;
+ if (filp || (flags & MAP_SHARED))
+ do_color_align = !is_32bit_task();
+
+ info.flags = 0;
+ info.length = len;
+ info.low_limit = mm->mmap_base;
+ info.high_limit = TASK_SIZE;
+ info.align_mask = do_color_align ? (mmap_align_mask << PAGE_SHIFT) : 0;
+ info.align_offset = pgoff << PAGE_SHIFT;
+ return vm_unmapped_area(&info);
+}
+
+unsigned long
+arch_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;
+ int do_color_align;
+
+ /* 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;
+ }
+
+ do_color_align = 0;
+ if (filp || (flags & MAP_SHARED))
+ do_color_align = !is_32bit_task();
+
+ 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 = do_color_align ? (mmap_align_mask << PAGE_SHIFT) : 0;
+ info.align_offset = pgoff << PAGE_SHIFT;
+ 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;
+}
+
+unsigned long randomize_et_dyn(void)
+{
+ unsigned long base;
+
+ base = (STACK_TOP / 3 * 2) & (~mmap_align_mask << PAGE_SHIFT);
+ return base + mmap_rnd();
+}
+
#ifndef CONFIG_64BIT
/*
@@ -177,4 +283,36 @@ void arch_pick_mmap_layout(struct mm_struct *mm)
}
}
+static int __init setup_mmap_rnd(void)
+{
+ struct cpuid cpu_id;
+
+ get_cpu_id(&cpu_id);
+ switch (cpu_id.machine) {
+ case 0x9672:
+ case 0x2064:
+ case 0x2066:
+ case 0x2084:
+ case 0x2086:
+ case 0x2094:
+ case 0x2096:
+ case 0x2097:
+ case 0x2098:
+ case 0x2817:
+ case 0x2818:
+ case 0x2827:
+ case 0x2828:
+ mmap_rnd_mask = 0x7ffUL;
+ mmap_align_mask = 0UL;
+ break;
+ case 0x2964: /* z13 */
+ default:
+ mmap_rnd_mask = 0x3ff80UL;
+ mmap_align_mask = 0x7fUL;
+ break;
+ }
+ return 0;
+}
+early_initcall(setup_mmap_rnd);
+
#endif