[RFC 1/9] asm-generic: mm_hooks: allow hooks to be overridden individually

From: Mark Rutland
Date: Mon Apr 03 2017 - 11:20:09 EST


Currently, an architecture must either implement all of the mm hooks
itself, or use all of those provided by the asm-generic implementation.
When an architecture only needs to override a single hook, it must copy
the stub implementations from the asm-generic version.

To avoid this repetition, allow each hook to be overridden indiviually,
by placing each under an #ifndef block. As architectures providing their
own hooks can't include this file today, this shouldn't adversely affect
any existing hooks.

Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: linux-arch@xxxxxxxxxxxxxxx
---
include/asm-generic/mm_hooks.h | 12 ++++++++++++
1 file changed, 12 insertions(+)

diff --git a/include/asm-generic/mm_hooks.h b/include/asm-generic/mm_hooks.h
index cc5d9a1..c5a4328 100644
--- a/include/asm-generic/mm_hooks.h
+++ b/include/asm-generic/mm_hooks.h
@@ -6,36 +6,48 @@
#ifndef _ASM_GENERIC_MM_HOOKS_H
#define _ASM_GENERIC_MM_HOOKS_H

+#ifndef arch_dup_mmap
static inline void arch_dup_mmap(struct mm_struct *oldmm,
struct mm_struct *mm)
{
}
+#endif

+#ifndef arch_exit_mmap
static inline void arch_exit_mmap(struct mm_struct *mm)
{
}
+#endif

+#ifndef arch_unmap
static inline void arch_unmap(struct mm_struct *mm,
struct vm_area_struct *vma,
unsigned long start, unsigned long end)
{
}
+#endif

+#ifndef arch_bprm_mm_init
static inline void arch_bprm_mm_init(struct mm_struct *mm,
struct vm_area_struct *vma)
{
}
+#endif

+#ifndef arch_vma_access_permitted
static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
bool write, bool execute, bool foreign)
{
/* by default, allow everything */
return true;
}
+#endif

+#ifndef arch_pte_access_permitted
static inline bool arch_pte_access_permitted(pte_t pte, bool write)
{
/* by default, allow everything */
return true;
}
+#endif
#endif /* _ASM_GENERIC_MM_HOOKS_H */
--
1.9.1