Re: [RFC v6 13/62] powerpc: track allocation status of all pkeys

On Thu, Jul 27, 2017 at 11:01:44AM -0300, Thiago Jung Bauermann wrote:

=20
Hello Ram,
=20
I'm still going through the patches and haven't formed a full picture of
the feature in my mind yet, so my comments today won't be particularly
insightful...
=20
But hopefully the comments that I currently have will be helpful anyway.

sure. thanx for taking the time to look through the patches.

=20
Ram Pai [off-list ref] writes:

quoted

diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/as=

m/pkeys.h

quoted

index 203d7de..09b268e 100644

--- a/arch/powerpc/include/asm/pkeys.h
+++ b/arch/powerpc/include/asm/pkeys.h

@@ -2,21 +2,87 @@
 #define _ASM_PPC64_PKEYS_H

 extern bool pkey_inited;
-#define ARCH_VM_PKEY_FLAGS 0
+#define arch_max_pkey()  32
+#define ARCH_VM_PKEY_FLAGS (VM_PKEY_BIT0 | VM_PKEY_BIT1 | VM_PKEY_BIT2=

 | \

quoted

+				VM_PKEY_BIT3 | VM_PKEY_BIT4)
+/*
+ * Bits are in BE format.
+ * NOTE: key 31, 1, 0 are not used.
+ * key 0 is used by default. It give read/write/execute permission.
+ * key 31 is reserved by the hypervisor.
+ * key 1 is recommended to be not used.
+ * PowerISA(3.0) page 1015, programming note.
+ */
+#define PKEY_INITIAL_ALLOCAION  0xc0000001

=20
There's a typo in the macro name, should be "ALLOCATION".

Thanks fixed it. The new version of the code, calculates the
allocation_mask at runtime, depending on the number of keys specified by
the device tree as well as other factors.  So the above macro is
replaced by a variable 'initial_allocation_mask'.

RP

=20
--=20
Thiago Jung Bauermann
IBM Linux Technology Center

--=20
Ram Pai