s390: avoid z13 cache aliasing

Avoid cache aliasing on z13 by aligning shared objects to multiples
of 512K. The virtual addresses of a page from a shared file needs
to have identical bits in the range 2^12 to 2^18.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 5 insertions, 3 deletions

diff --git a/arch/s390/include/asm/elf.h b/arch/s390/include/asm/elf.h
index f6e43d39e3d8..c9df40b5c0ac 100644
--- a/arch/s390/include/asm/elf.h
+++ b/arch/s390/include/asm/elf.h
@@ -163,8 +163,8 @@ extern unsigned int vdso_enabled;
    the loader.  We need to make sure that it is out of the way of the program
    that it will "exec", and that there is sufficient room for the brk.  */
 
-extern unsigned long randomize_et_dyn(unsigned long base);
-#define ELF_ET_DYN_BASE         (randomize_et_dyn(STACK_TOP / 3 * 2))
+extern unsigned long randomize_et_dyn(void);
+#define ELF_ET_DYN_BASE         randomize_et_dyn()
 
 /* This yields a mask that user programs can use to figure out what
    instruction set this CPU supports. */
@@ -209,7 +209,9 @@ do {								\
 } while (0)
 #endif /* CONFIG_COMPAT */
 
-#define STACK_RND_MASK  0x7ffUL
+extern unsigned long mmap_rnd_mask;
+
+#define STACK_RND_MASK  (mmap_rnd_mask)
 
 #define ARCH_DLINFO                                                         \
 do {                                                                        \