diff mbox series

[1/2] mm: Change mmap_rnd_bits_max to __ro_after_init

Message ID 20230929211155.3910949-5-samitolvanen@google.com
State New
Headers
Series riscv: Increase mmap_rnd_bits_max on Sv48/57 |

Commit Message

Sami Tolvanen Sept. 29, 2023, 9:11 p.m. UTC 
  Allow mmap_rnd_bits_max to be updated on architectures that
determine virtual address space size at runtime instead of relying
on Kconfig options by changing it from const to __ro_after_init.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
---
 include/linux/mm.h | 2 +-
 mm/mmap.c          | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

Comments

Kees Cook Sept. 29, 2023, 9:55 p.m. UTC | #1 
On Fri, Sep 29, 2023 at 09:11:57PM +0000, Sami Tolvanen wrote:
> Allow mmap_rnd_bits_max to be updated on architectures that
> determine virtual address space size at runtime instead of relying
> on Kconfig options by changing it from const to __ro_after_init.
> 
> Signed-off-by: Sami Tolvanen <samitolvanen@google.com>

Just the kind of thing __ro_after_init was made for. :)

Reviewed-by: Kees Cook <keescook@chromium.org>
diff mbox series

Patch

diff --git a/include/linux/mm.h b/include/linux/mm.h
index bf5d0b1b16f4..72a98b2afaf9 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -86,7 +86,7 @@  extern int sysctl_legacy_va_layout;
 
 #ifdef CONFIG_HAVE_ARCH_MMAP_RND_BITS
 extern const int mmap_rnd_bits_min;
-extern const int mmap_rnd_bits_max;
+extern int mmap_rnd_bits_max __ro_after_init;
 extern int mmap_rnd_bits __read_mostly;
 #endif
 #ifdef CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS
diff --git a/mm/mmap.c b/mm/mmap.c
index b56a7f0c9f85..ed1b178b223a 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -64,7 +64,7 @@ 
 
 #ifdef CONFIG_HAVE_ARCH_MMAP_RND_BITS
 const int mmap_rnd_bits_min = CONFIG_ARCH_MMAP_RND_BITS_MIN;
-const int mmap_rnd_bits_max = CONFIG_ARCH_MMAP_RND_BITS_MAX;
+int mmap_rnd_bits_max __ro_after_init = CONFIG_ARCH_MMAP_RND_BITS_MAX;
 int mmap_rnd_bits __read_mostly = CONFIG_ARCH_MMAP_RND_BITS;
 #endif
 #ifdef CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS