Commit 6f6a841f authored by Mike Rapoport's avatar Mike Rapoport Committed by Linus Torvalds
Browse files

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: default avatarMike Rapoport <rppt@linux.ibm.com>
Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 90647d9d

tools/testing/selftests/vm/gup_test.c

+2 −1
Original line number Diff line number Diff line
@@ -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 */

tools/testing/selftests/vm/util.h

+24 −3
Original line number Diff line number Diff line
@@ -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;



static inline unsigned int page_size(void)

{

	if (!__page_size)

		__page_size = sysconf(_SC_PAGESIZE);

	return __page_size;

}



#define PAGE_SIZE (1 << PAGE_SHIFT)

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)