• Daniel Cashman's avatar
    x86: mm: support ARCH_MMAP_RND_BITS · 9e08f57d
    Daniel Cashman authored
    x86: arch_mmap_rnd() uses hard-coded values, 8 for 32-bit and 28 for
    64-bit, to generate the random offset for the mmap base address.  This
    value represents a compromise between increased ASLR effectiveness and
    avoiding address-space fragmentation.  Replace it with a Kconfig option,
    which is sensibly bounded, so that platform developers may choose where
    to place this compromise.  Keep default values as new minimums.
    Signed-off-by: default avatarDaniel Cashman <dcashman@google.com>
    Cc: Russell King <linux@arm.linux.org.uk>
    Acked-by: default avatarKees Cook <keescook@chromium.org>
    Cc: Ingo Molnar <mingo@kernel.org>
    Cc: Jonathan Corbet <corbet@lwn.net>
    Cc: Don Zickus <dzickus@redhat.com>
    Cc: Eric W. Biederman <ebiederm@xmission.com>
    Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
    Cc: Josh Poimboeuf <jpoimboe@redhat.com>
    Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
    Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
    Cc: Andrea Arcangeli <aarcange@redhat.com>
    Cc: Mel Gorman <mgorman@suse.de>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: David Rientjes <rientjes@google.com>
    Cc: Mark Salyzyn <salyzyn@android.com>
    Cc: Jeff Vander Stoep <jeffv@google.com>
    Cc: Nick Kralevich <nnk@google.com>
    Cc: Catalin Marinas <catalin.marinas@arm.com>
    Cc: Will Deacon <will.deacon@arm.com>
    Cc: "H. Peter Anvin" <hpa@zytor.com>
    Cc: Hector Marco-Gisbert <hecmargi@upv.es>
    Cc: Borislav Petkov <bp@suse.de>
    Cc: Ralf Baechle <ralf@linux-mips.org>
    Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
    Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
    Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    9e08f57d
mmap.c 3.33 KB