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From:   Ram Pai <linuxram@us.ibm.com>
To:     mpe@ellerman.id.au, mingo@redhat.com, akpm@linux-foundation.org
Cc:     linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org, x86@kernel.org,
        linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
        dave.hansen@intel.com, benh@kernel.crashing.org, paulus@samba.org,
        khandual@linux.vnet.ibm.com, aneesh.kumar@linux.vnet.ibm.com,
        bsingharora@gmail.com, hbabu@us.ibm.com, mhocko@kernel.org,
        bauerman@linux.vnet.ibm.com, ebiederm@xmission.com,
        linuxram@us.ibm.com, corbet@lwn.net, arnd@arndb.de
Subject: [PATCH v13 3/3] mm, powerpc, x86: introduce an additional vma bit for powerpc pkey
Date:   Fri,  4 May 2018 14:59:42 -0700
Message-Id: <1525471183-21277-3-git-send-email-linuxram@us.ibm.com>
In-Reply-To: <1525471183-21277-1-git-send-email-linuxram@us.ibm.com>
References: <1525471183-21277-1-git-send-email-linuxram@us.ibm.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Only 4bits are allocated in the vma flags to hold 16 keys. This is
sufficient on x86. PowerPC supports 32 keys, which needs 5bits.
Allocate an  additional bit.

cc: Dave Hansen <dave.hansen@intel.com>
cc: Michael Ellermen <mpe@ellerman.id.au>
cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
---
 fs/proc/task_mmu.c |    1 +
 include/linux/mm.h |    8 +++++++-
 2 files changed, 8 insertions(+), 1 deletions(-)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 0c9e392..3ddddc7 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -679,6 +679,7 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
 		[ilog2(VM_PKEY_BIT1)]	= "",
 		[ilog2(VM_PKEY_BIT2)]	= "",
 		[ilog2(VM_PKEY_BIT3)]	= "",
+		[ilog2(VM_PKEY_BIT4)]	= "",
 #endif /* CONFIG_ARCH_HAS_PKEYS */
 	};
 	size_t i;
diff --git a/include/linux/mm.h b/include/linux/mm.h
index c6a6f24..cca67d1 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -230,10 +230,16 @@ extern int overcommit_kbytes_handler(struct ctl_table *, int, void __user *,
 
 #ifdef CONFIG_ARCH_HAS_PKEYS
 # define VM_PKEY_SHIFT	VM_HIGH_ARCH_BIT_0
-# define VM_PKEY_BIT0	VM_HIGH_ARCH_0	/* A protection key is a 4-bit value */
+/* Protection key is a 4-bit value on x86 and 5-bit value on ppc64   */
+# define VM_PKEY_BIT0	VM_HIGH_ARCH_0
 # define VM_PKEY_BIT1	VM_HIGH_ARCH_1
 # define VM_PKEY_BIT2	VM_HIGH_ARCH_2
 # define VM_PKEY_BIT3	VM_HIGH_ARCH_3
+#if defined(CONFIG_PPC)
+# define VM_PKEY_BIT4	VM_HIGH_ARCH_4
+#else 
+# define VM_PKEY_BIT4	0
+#endif
 #endif /* CONFIG_ARCH_HAS_PKEYS */
 
 #if defined(CONFIG_X86)
-- 
1.7.1