On Mon, Oct 23, 2017 at 02:58:55PM +0530, Aneesh Kumar K.V wrote:

"Aneesh Kumar K.V" [off-list ref] writes:

quoted

Ram Pai [off-list ref] writes:

quoted

powerpc needs an additional vma bit to support 32 keys.
Till the additional vma bit lands in include/linux/mm.h
we have to define  it  in powerpc specific header file.
This is  needed to get pkeys working on power.

Signed-off-by: Ram Pai <redacted>
---
 arch/powerpc/include/asm/pkeys.h |   18 ++++++++++++++++++
 1 files changed, 18 insertions(+), 0 deletions(-)

diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h
index c02305a..44e01a2 100644
--- a/arch/powerpc/include/asm/pkeys.h
+++ b/arch/powerpc/include/asm/pkeys.h

@@ -3,6 +3,24 @@

 extern bool pkey_inited;
 extern bool pkey_execute_disable_support;
+
+/*
+ * powerpc needs an additional vma bit to support 32 keys.
+ * Till the additional vma bit lands in include/linux/mm.h
+ * we have to carry the hunk below. This is  needed to get
+ * pkeys working on power. -- Ram
+ */
+#ifndef VM_HIGH_ARCH_BIT_4
+#define VM_HIGH_ARCH_BIT_4	36
+#define VM_HIGH_ARCH_4	BIT(VM_HIGH_ARCH_BIT_4)
+#define VM_PKEY_SHIFT VM_HIGH_ARCH_BIT_0
+#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
+#define VM_PKEY_BIT4	VM_HIGH_ARCH_4
+#endif
+
 #define ARCH_VM_PKEY_FLAGS 0

Do we want them in pkeys.h ? Even if they are arch specific for the
existing ones we have them in include/linux/mm.h. IIUC, vmflags details
are always in mm.h? This will be the first exception to that?

Also can we move that 

#if defined (CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS)
# 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 */
# define VM_PKEY_BIT1	VM_HIGH_ARCH_1
# define VM_PKEY_BIT2	VM_HIGH_ARCH_2
# define VM_PKEY_BIT3	VM_HIGH_ARCH_3
#endif

to

#if defined (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 */
# define VM_PKEY_BIT1	VM_HIGH_ARCH_1
# define VM_PKEY_BIT2	VM_HIGH_ARCH_2
# define VM_PKEY_BIT3	VM_HIGH_ARCH_3
#endif


And then later update the generic to handle PKEY_BIT4?

Yes. The above changes have been implemented in a patch sent to the mm
mailing list as well as to lkml.

https://lkml.org/lkml/2017/9/15/504

RP