tools: testing: add simple __mmap_region() userland test

Introduce demonstrative, basic, __mmap_region() test upon which we can
base further work upon moving forwards.

This simply asserts that mappings can be made and merges occur as
expected.

As part of this change, fix the security_vm_enough_memory_mm() stub which
was previously incorrectly implemented.

Link: https://lkml.kernel.org/r/20241213162409.41498-1-lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Jann Horn <jannh@google.com>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/tools/testing/vma/vma.c b/tools/testing/vma/vma.c
index 920fba58884e3e90e15388322d4e4b3253aeeb43..04ab45e27fb8eea64f5c4e50ad74102d647d6ceb 100644 (file)
--- a/tools/testing/vma/vma.c
+++ b/tools/testing/vma/vma.c
@@ -1574,6 +1574,57 @@ static bool test_expand_only_mode(void)
        return true;
 }
 
+static bool test_mmap_region_basic(void)
+{
+       struct mm_struct mm = {};
+       unsigned long addr;
+       struct vm_area_struct *vma;
+       VMA_ITERATOR(vmi, &mm, 0);
+
+       current->mm = &mm;
+
+       /* Map at 0x300000, length 0x3000. */
+       addr = __mmap_region(NULL, 0x300000, 0x3000,
+                            VM_READ | VM_WRITE | VM_MAYREAD | VM_MAYWRITE,
+                            0x300, NULL);
+       ASSERT_EQ(addr, 0x300000);
+
+       /* Map at 0x250000, length 0x3000. */
+       addr = __mmap_region(NULL, 0x250000, 0x3000,
+                            VM_READ | VM_WRITE | VM_MAYREAD | VM_MAYWRITE,
+                            0x250, NULL);
+       ASSERT_EQ(addr, 0x250000);
+
+       /* Map at 0x303000, merging to 0x300000 of length 0x6000. */
+       addr = __mmap_region(NULL, 0x303000, 0x3000,
+                            VM_READ | VM_WRITE | VM_MAYREAD | VM_MAYWRITE,
+                            0x303, NULL);
+       ASSERT_EQ(addr, 0x303000);
+
+       /* Map at 0x24d000, merging to 0x250000 of length 0x6000. */
+       addr = __mmap_region(NULL, 0x24d000, 0x3000,
+                            VM_READ | VM_WRITE | VM_MAYREAD | VM_MAYWRITE,
+                            0x24d, NULL);
+       ASSERT_EQ(addr, 0x24d000);
+
+       ASSERT_EQ(mm.map_count, 2);
+
+       for_each_vma(vmi, vma) {
+               if (vma->vm_start == 0x300000) {
+                       ASSERT_EQ(vma->vm_end, 0x306000);
+                       ASSERT_EQ(vma->vm_pgoff, 0x300);
+               } else if (vma->vm_start == 0x24d000) {
+                       ASSERT_EQ(vma->vm_end, 0x253000);
+                       ASSERT_EQ(vma->vm_pgoff, 0x24d);
+               } else {
+                       ASSERT_FALSE(true);
+               }
+       }
+
+       cleanup_mm(&mm, &vmi);
+       return true;
+}
+
 int main(void)
 {
        int num_tests = 0, num_fail = 0;
@@ -1607,6 +1658,8 @@ int main(void)
        TEST(copy_vma);
        TEST(expand_only_mode);
 
+       TEST(mmap_region_basic);
+
 #undef TEST
 
        printf("%d tests run, %d passed, %d failed.\n",

diff --git a/tools/testing/vma/vma_internal.h b/tools/testing/vma/vma_internal.h
index b973b3e41c834215732dbe1220d49aa6869cd102..ae635eecbfa823d3dfb2e473e8d77ac631b4714e 100644 (file)
--- a/tools/testing/vma/vma_internal.h
+++ b/tools/testing/vma/vma_internal.h
@@ -996,7 +996,7 @@ static inline bool is_file_hugepages(struct file *)
 
 static inline int security_vm_enough_memory_mm(struct mm_struct *, long)
 {
-       return true;
+       return 0;
 }
 
 static inline bool may_expand_vm(struct mm_struct *, vm_flags_t, unsigned long)