bionic: tests: Remove PAGE_SIZE usage

Instead of the hardcoded PAGE_SIZE 4096 macro, use the
real system page-size as queried from the auxillary vector.

Bug: 277272383
Bug: 300367402
Test: atest -c bionic-unit-tests
Change-Id: I2f1ad1b431e36ef45e9f53f713ced6b06e0d4f70
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
diff --git a/tests/dlfcn_test.cpp b/tests/dlfcn_test.cpp
index 67f1973..5b3eaf8 100644
--- a/tests/dlfcn_test.cpp
+++ b/tests/dlfcn_test.cpp
@@ -824,6 +824,8 @@
 }
 
 TEST(dlfcn, dlclose_unload) {
+  const size_t kPageSize = getpagesize();
+
   void* handle = dlopen("libtest_simple.so", RTLD_NOW);
   ASSERT_TRUE(handle != nullptr) << dlerror();
   uint32_t* taxicab_number = static_cast<uint32_t*>(dlsym(handle, "dlopen_testlib_taxicab_number"));
@@ -833,8 +835,8 @@
   // Making sure that the library has been unmapped as part of library unload
   // process. Note that mprotect somewhat counter-intuitively returns ENOMEM in
   // this case.
-  uintptr_t page_start = reinterpret_cast<uintptr_t>(taxicab_number) & ~(PAGE_SIZE - 1);
-  ASSERT_TRUE(mprotect(reinterpret_cast<void*>(page_start), PAGE_SIZE, PROT_NONE) != 0);
+  uintptr_t page_start = reinterpret_cast<uintptr_t>(taxicab_number) & ~(kPageSize - 1);
+  ASSERT_TRUE(mprotect(reinterpret_cast<void*>(page_start), kPageSize, PROT_NONE) != 0);
   ASSERT_ERRNO(ENOMEM);
 }