selftest/vm: add helpers to detect PAGE_SIZE and PAGE_SHIFT

PAGE_SIZE is not 4096 in many configurations, particularly ppc64 uses 64K
pages in majority of cases.

Add helpers to detect PAGE_SIZE and PAGE_SHIFT dynamically.

Without this tests are broken w.r.t reading /proc/self/pagemap

    if (pread(pagemap_fd, ent, sizeof(ent),
              (uintptr_t)ptr >> (PAGE_SHIFT - 3)) != sizeof(ent))
              err(2, "read pagemap");

Link: https://lkml.kernel.org/r/20220307054355.149820-2-aneesh.kumar@linux.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/tools/testing/selftests/vm/gup_test.c b/tools/testing/selftests/vm/gup_test.c
index fe043f67798b0b1b6b2578450ca2dbda99b5b5bd..cda837a147364bb63bd7c8d7a936c937c726e2ff 100644 (file)
--- a/tools/testing/selftests/vm/gup_test.c
+++ b/tools/testing/selftests/vm/gup_test.c
@@ -10,8 +10,9 @@
 #include <assert.h>
 #include "../../../../mm/gup_test.h"
 
+#include "util.h"
+
 #define MB (1UL << 20)
-#define PAGE_SIZE sysconf(_SC_PAGESIZE)
 
 /* Just the flags we need, copied from mm.h: */
 #define FOLL_WRITE     0x01    /* check pte is writable */

diff --git a/tools/testing/selftests/vm/util.h b/tools/testing/selftests/vm/util.h
index 0f0a0f345d7688bdf1008c9a0f8c5db2c881a9ac..b27d26199334ffee9312527fd155379a3db00376 100644 (file)
--- a/tools/testing/selftests/vm/util.h
+++ b/tools/testing/selftests/vm/util.h
@@ -6,11 +6,32 @@
 #include <stdint.h>
 #include <sys/mman.h>
 #include <err.h>
+#include <string.h> /* ffsl() */
+#include <unistd.h> /* _SC_PAGESIZE */
 
-#define PAGE_SHIFT     12
-#define HPAGE_SHIFT    21
+static unsigned int __page_size;
+static unsigned int __page_shift;
 
-#define PAGE_SIZE (1 << PAGE_SHIFT)
+static inline unsigned int page_size(void)
+{
+       if (!__page_size)
+               __page_size = sysconf(_SC_PAGESIZE);
+       return __page_size;
+}
+
+static inline unsigned int page_shift(void)
+{
+       if (!__page_shift)
+               __page_shift = (ffsl(page_size()) - 1);
+       return __page_shift;
+}
+
+#define PAGE_SHIFT     (page_shift())
+#define PAGE_SIZE      (page_size())
+/*
+ * On ppc64 this will only work with radix 2M hugepage size
+ */
+#define HPAGE_SHIFT 21
 #define HPAGE_SIZE (1 << HPAGE_SHIFT)
 
 #define PAGEMAP_PRESENT(ent)   (((ent) & (1ull << 63)) != 0)