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From:   Christophe Leroy <christophe.leroy@c-s.fr>
Subject: [RFC PATCH v1 2/6] powerpc: Add framework for Kernel Userspace
 Protection
To:     Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Michael Ellerman <mpe@ellerman.id.au>, ruscur@russell.cc
Cc:     linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Date:   Wed,  7 Nov 2018 16:56:29 +0000 (UTC)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

This patch adds a skeleton for Kernel Userspace Protection
functionnalities like Kernel Userspace Access Protection and
Kernel Userspace Execution Prevention

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
 arch/powerpc/include/asm/mmu.h | 2 ++
 arch/powerpc/kernel/setup_64.c | 1 +
 arch/powerpc/mm/init-common.c  | 4 ++++
 arch/powerpc/mm/init_32.c      | 2 ++
 4 files changed, 9 insertions(+)

diff --git a/arch/powerpc/include/asm/mmu.h b/arch/powerpc/include/asm/mmu.h
index eb20eb3b8fb0..39c51dcba8f4 100644
--- a/arch/powerpc/include/asm/mmu.h
+++ b/arch/powerpc/include/asm/mmu.h
@@ -268,6 +268,8 @@ static inline u16 get_mm_addr_key(struct mm_struct *mm, unsigned long address)
 }
 #endif /* CONFIG_PPC_MEM_KEYS */
 
+void setup_kup(void);
+
 #endif /* !__ASSEMBLY__ */
 
 /* The kernel use the constants below to index in the page sizes array.
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 2a51e4cc8246..4e21b10ff38d 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -372,6 +372,7 @@ void __init early_setup(unsigned long dt_ptr)
 	 */
 	btext_map();
 #endif /* CONFIG_PPC_EARLY_DEBUG_BOOTX */
+	setup_kup();
 }
 
 #ifdef CONFIG_SMP
diff --git a/arch/powerpc/mm/init-common.c b/arch/powerpc/mm/init-common.c
index 2b656e67f2ea..e469814e8290 100644
--- a/arch/powerpc/mm/init-common.c
+++ b/arch/powerpc/mm/init-common.c
@@ -25,6 +25,10 @@
 #include <asm/pgalloc.h>
 #include <asm/pgtable.h>
 
+void setup_kup(void)
+{
+}
+
 static void pgd_ctor(void *addr)
 {
 	memset(addr, 0, PGD_TABLE_SIZE);
diff --git a/arch/powerpc/mm/init_32.c b/arch/powerpc/mm/init_32.c
index 3e59e5d64b01..4012ee6f0754 100644
--- a/arch/powerpc/mm/init_32.c
+++ b/arch/powerpc/mm/init_32.c
@@ -182,6 +182,8 @@ void __init MMU_init(void)
 	btext_unmap();
 #endif
 
+	setup_kup();
+
 	/* Shortly after that, the entire linear mapping will be available */
 	memblock_set_current_limit(lowmem_end_addr);
 }
-- 
2.13.3