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From:   Mark Rutland <mark.rutland@arm.com>
To:     linux-arm-kernel@lists.infradead.org
Cc:     arnd@arndb.de, catalin.marinas@arm.com, cdall@kernel.org,
        drjones@redhat.com, kvmarm@lists.cs.columbia.edu,
        linux-arch@vger.kernel.org, marc.zyngier@arm.com,
        mark.rutland@arm.com, ramana.radhakrishnan@arm.com,
        suzuki.poulose@arm.com, will.deacon@arm.com,
        linux-kernel@vger.kernel.org, awallis@codeaurora.org,
        kernel-hardening@lists.openwall.com
Subject: [PATCHv3 06/11] asm-generic: mm_hooks: allow hooks to be overridden individually
Date:   Tue, 17 Apr 2018 19:37:30 +0100
Message-Id: <20180417183735.56985-7-mark.rutland@arm.com>
In-Reply-To: <20180417183735.56985-1-mark.rutland@arm.com>
References: <20180417183735.56985-1-mark.rutland@arm.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

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@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linux-arch@vger.kernel.org
---
 include/asm-generic/mm_hooks.h | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/include/asm-generic/mm_hooks.h b/include/asm-generic/mm_hooks.h
index 8ac4e68a12f0..2b3ee15d3702 100644
--- a/include/asm-generic/mm_hooks.h
+++ b/include/asm-generic/mm_hooks.h
@@ -7,31 +7,42 @@
 #ifndef _ASM_GENERIC_MM_HOOKS_H
 #define _ASM_GENERIC_MM_HOOKS_H
 
+#ifndef arch_dup_mmap
 static inline int arch_dup_mmap(struct mm_struct *oldmm,
 				struct mm_struct *mm)
 {
 	return 0;
 }
+#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
+
 #endif	/* _ASM_GENERIC_MM_HOOKS_H */
-- 
2.11.0