From 67f3977f805b34cf0e41090679800d2091d41d49 Mon Sep 17 00:00:00 2001 From: Alexandre Ghiti Date: Mon, 23 Sep 2019 15:38:47 -0700 Subject: arm64, mm: move generic mmap layout functions to mm arm64 handles top-down mmap layout in a way that can be easily reused by other architectures, so make it available in mm. It then introduces a new config ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT that can be set by other architectures to benefit from those functions. Note that this new config depends on MMU being enabled, if selected without MMU support, a warning will be thrown. Link: http://lkml.kernel.org/r/20190730055113.23635-5-alex@ghiti.fr Signed-off-by: Alexandre Ghiti Suggested-by: Christoph Hellwig Acked-by: Catalin Marinas Acked-by: Kees Cook Reviewed-by: Christoph Hellwig Reviewed-by: Luis Chamberlain Cc: Albert Ou Cc: Alexander Viro Cc: James Hogan Cc: Palmer Dabbelt Cc: Paul Burton Cc: Ralf Baechle Cc: Russell King Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/Kconfig | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'arch/Kconfig') diff --git a/arch/Kconfig b/arch/Kconfig index 0fcf8ec1e098..dfce421b8e8a 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -706,6 +706,16 @@ config HAVE_ARCH_COMPAT_MMAP_BASES and vice-versa 32-bit applications to call 64-bit mmap(). Required for applications doing different bitness syscalls. +# This allows to use a set of generic functions to determine mmap base +# address by giving priority to top-down scheme only if the process +# is not in legacy mode (compat task, unlimited stack size or +# sysctl_legacy_va_layout). +# Architecture that selects this option can provide its own version of: +# - STACK_RND_MASK +config ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT + bool + depends on MMU + config HAVE_COPY_THREAD_TLS bool help -- cgit v1.2.3