Re: [PATCH 03/25] powerpc: track allocation status of all pkeys

On Sat, Oct 07, 2017 at 09:02:55PM +1100, Michael Ellerman wrote:

Ram Pai [off-list ref] writes:

quoted

Total 32 keys are available on power7 and above. However
pkey 0,1 are reserved. So effectively we  have  30 pkeys.

On 4K kernels, we do not  have  5  bits  in  the  PTE to
represent  all the keys; we only have 3bits.Two of those
keys are reserved; pkey 0 and pkey 1. So effectively  we
have 6 pkeys.

This patch keeps track of reserved keys, allocated  keys
and keys that are currently free.

Also it  adds  skeletal  functions  and macros, that the
architecture-independent code expects to be available.

Signed-off-by: Ram Pai <redacted>
---
 arch/powerpc/include/asm/book3s/64/mmu.h |    9 ++++
 arch/powerpc/include/asm/mmu_context.h   |    1 +
 arch/powerpc/include/asm/pkeys.h         |   72 ++++++++++++++++++++++++++++--
 arch/powerpc/mm/mmu_context_book3s64.c   |    2 +
 arch/powerpc/mm/pkeys.c                  |   28 ++++++++++++
 5 files changed, 108 insertions(+), 4 deletions(-)

This doesn't build for me, with pseries_le_defconfig. I assume it built
for you. So something has changed upstream maybe?

Yes. :(
The following commit upstream broke my patches.
df3735c5b40fad8d0d28eb8ab065fe955b3347ee

Will fix and send you a patch.

RP

In file included from ../include/linux/pkeys.h:8:0,
                 from ../mm/mprotect.c:26:
../mm/mprotect.c: In function ‘do_mprotect_pkey’:
../arch/powerpc/include/asm/pkeys.h:27:29: error: ‘VM_PKEY_BIT0’ undeclared (first use in this function)
 #define ARCH_VM_PKEY_FLAGS (VM_PKEY_BIT0 | VM_PKEY_BIT1 | VM_PKEY_BIT2 | \
                             ^

..snip...