[PATCH] Adds vm_operations_struct.access to vm_ops, allowing access via ptrace (and thus, gdb) and /dev/mem

[Markus Dreseler]

Exporting generic_access_phys is already in the linux sources as of 
1d1fdd95df681f0c065d90ffaafa215a0e8825e2.
VM_IO was added so that get_user_pages uses vm_ops.access.
---
  fs/pmfs/xip.c |    8 +++++++-
  mm/memory.c   |    1 +
  2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/fs/pmfs/xip.c b/fs/pmfs/xip.c
index c7471be..f29f6f5 100644
--- a/fs/pmfs/xip.c
+++ b/fs/pmfs/xip.c
@@ -643,10 +643,16 @@ static int pmfs_xip_file_hpage_fault(struct 
vm_area_struct *vma,

  static const struct vm_operations_struct pmfs_xip_vm_ops = {
  	.fault	= pmfs_xip_file_fault,
+	#ifdef CONFIG_HAVE_IOREMAP_PROT
+	.access = generic_access_phys,
+	#endif
  };

  static const struct vm_operations_struct pmfs_xip_hpage_vm_ops = {
  	.fault	= pmfs_xip_file_hpage_fault,
+	#ifdef CONFIG_HAVE_IOREMAP_PROT
+	.access = generic_access_phys,
+	#endif
  };

  static inline int pmfs_has_huge_mmap(struct super_block *sb)
@@ -664,7 +670,7 @@ int pmfs_xip_file_mmap(struct file *file, struct 
vm_area_struct *vma)

  	file_accessed(file);

-	vma->vm_flags |= VM_MIXEDMAP;
+	vma->vm_flags |= (VM_MIXEDMAP | VM_IO);

  	block_sz = pmfs_data_block_size(vma, vma->vm_start, 0);
  	if (pmfs_has_huge_mmap(file->f_mapping->host->i_sb) &&
diff --git a/mm/memory.c b/mm/memory.c
index 6e91ac7..45ba28e 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4248,6 +4248,7 @@ int generic_access_phys(struct vm_area_struct 
*vma, unsigned long addr,

  	return len;
  }
+EXPORT_SYMBOL_GPL(generic_access_phys);
  #endif

  /*
-- 
1.7.9.5