--- /dev/null
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/syscalls.h>
+#include <linux/mm.h>
+#include <linux/fs.h>
+#include <linux/smp.h>
+#include <linux/sem.h>
+#include <linux/msg.h>
+#include <linux/shm.h>
+#include <linux/stat.h>
+#include <linux/mman.h>
+#include <linux/file.h>
+#include <linux/utsname.h>
+#include <linux/personality.h>
+#include <linux/random.h>
+#include <linux/uaccess.h>
+#include <linux/elf.h>
+
+#include <asm/ia32.h>
+#include <asm/syscalls.h>
+
+/*
+ * Align a virtual address to avoid aliasing in the I$ on AMD F15h.
+ */
+static unsigned long get_align_mask(void)
+{
+ /* handle 32- and 64-bit case with a single conditional */
+ if (va_align.flags < 0 || !(va_align.flags & (2 - mmap_is_ia32())))
+ return 0;
+
+ if (!(current->flags & PF_RANDOMIZE))
+ return 0;
+
+ return va_align.mask;
+}
+
+/*
+ * To avoid aliasing in the I$ on AMD F15h, the bits defined by the
+ * va_align.bits, [12:upper_bit), are set to a random value instead of
+ * zeroing them. This random value is computed once per boot. This form
+ * of ASLR is known as "per-boot ASLR".
+ *
+ * To achieve this, the random value is added to the info.align_offset
+ * value before calling vm_unmapped_area() or ORed directly to the
+ * address.
+ */
+static unsigned long get_align_bits(void)
+{
+ return va_align.bits & get_align_mask();
+}
+
+unsigned long align_vdso_addr(unsigned long addr)
+{
+ unsigned long align_mask = get_align_mask();
+ addr = (addr + align_mask) & ~align_mask;
+ return addr | get_align_bits();
+}
+
+static int __init control_va_addr_alignment(char *str)
+{
+ /* guard against enabling this on other CPU families */
+ if (va_align.flags < 0)
+ return 1;
+
+ if (*str == 0)
+ return 1;
+
+ if (*str == '=')
+ str++;
+
+ if (!strcmp(str, "32"))
+ va_align.flags = ALIGN_VA_32;
+ else if (!strcmp(str, "64"))
+ va_align.flags = ALIGN_VA_64;
+ else if (!strcmp(str, "off"))
+ va_align.flags = 0;
+ else if (!strcmp(str, "on"))
+ va_align.flags = ALIGN_VA_32 | ALIGN_VA_64;
+ else
+ return 0;
+
+ return 1;
+}
+__setup("align_va_addr", control_va_addr_alignment);
+
+SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
+ unsigned long, prot, unsigned long, flags,
+ unsigned long, fd, unsigned long, off)
+{
+ long error;
+ error = -EINVAL;
+ if (off & ~PAGE_MASK)
+ goto out;
+
+ error = sys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
+out:
+ return error;
+}
+
+static void find_start_end(unsigned long flags, unsigned long *begin,
+ unsigned long *end)
+{
+ if (!test_thread_flag(TIF_ADDR32) && (flags & MAP_32BIT)) {
+ unsigned long new_begin;
+ /* This is usually used needed to map code in small
+ model, so it needs to be in the first 31bit. Limit
+ it to that. This means we need to move the
+ unmapped base down for this case. This can give
+ conflicts with the heap, but we assume that glibc
+ malloc knows how to fall back to mmap. Give it 1GB
+ of playground for now. -AK */
+ *begin = 0x40000000;
+ *end = 0x80000000;
+ if (current->flags & PF_RANDOMIZE) {
+ new_begin = randomize_range(*begin, *begin + 0x02000000, 0);
+ if (new_begin)
+ *begin = new_begin;
+ }
+ } else {
+ *begin = current->mm->mmap_legacy_base;
+ *end = TASK_SIZE;
+ }
+}
+
+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;
+ unsigned long begin, end;
+
+ if (flags & MAP_FIXED)
+ return addr;
+
+ find_start_end(flags, &begin, &end);
+
+ if (len > end)
+ return -ENOMEM;
+
+ if (addr) {
+ addr = PAGE_ALIGN(addr);
+ vma = find_vma(mm, addr);
+ if (end - len >= addr &&
+ (!vma || addr + len <= vma->vm_start))
+ return addr;
+ }
+
+ info.flags = 0;
+ info.length = len;
+ info.low_limit = begin;
+ info.high_limit = end;
+ info.align_mask = 0;
+ info.align_offset = pgoff << PAGE_SHIFT;
+ if (filp) {
+ info.align_mask = get_align_mask();
+ info.align_offset += get_align_bits();
+ }
+ 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;
+
+ /* requested length too big for entire address space */
+ if (len > TASK_SIZE)
+ return -ENOMEM;
+
+ if (flags & MAP_FIXED)
+ return addr;
+
+ /* for MAP_32BIT mappings we force the legacy mmap base */
+ if (!test_thread_flag(TIF_ADDR32) && (flags & MAP_32BIT))
+ goto bottomup;
+
+ /* requesting a specific address */
+ if (addr) {
+ addr = PAGE_ALIGN(addr);
+ vma = find_vma(mm, addr);
+ if (TASK_SIZE - len >= addr &&
+ (!vma || addr + len <= vma->vm_start))
+ return addr;
+ }
+
+ info.flags = VM_UNMAPPED_AREA_TOPDOWN;
+ info.length = len;
+ info.low_limit = PAGE_SIZE;
+ info.high_limit = mm->mmap_base;
+ info.align_mask = 0;
+ info.align_offset = pgoff << PAGE_SHIFT;
+ if (filp) {
+ info.align_mask = get_align_mask();
+ info.align_offset += get_align_bits();
+ }
+ addr = vm_unmapped_area(&info);
+ if (!(addr & ~PAGE_MASK))
+ return addr;
+ VM_BUG_ON(addr != -ENOMEM);
+
+bottomup:
+ /*
+ * 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.
+ */
+ return arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
+}
Code Review / kvmfornfv.git / blobdiff