12 Commits

Author SHA1 Message Date
Thiago Jung Bauermann
c5cc1f4df6 powerpc/ptrace: Add memory protection key regset
The AMR/IAMR/UAMOR are part of the program context.
Allow it to be accessed via ptrace and through core files.

Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-01-20 22:59:06 +11:00
Ram Pai
f2407ef3ba powerpc: helper to validate key-access permissions of a pte
helper function that checks if the read/write/execute is allowed
on the pte.

Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-01-20 22:59:03 +11:00
Ram Pai
a6590ca55f powerpc: Program HPTE key protection bits
Map the PTE protection key bits to the HPTE key protection bits,
while creating HPTE  entries.

Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-01-20 22:59:03 +11:00
Ram Pai
eb95d016ce powerpc: map vma key-protection bits to pte key bits.
Map  the  key  protection  bits of the vma to the pkey bits in
the PTE.

The PTE  bits used  for pkey  are  3,4,5,6  and 57. The  first
four bits are the same four bits that were freed up  initially
in this patch series. remember? :-) Without those four bits
this patch wouldn't be possible.

BUT, on 4k kernel, bit 3, and 4 could not be freed up. remember?
Hence we have to be satisfied with 5, 6 and 7.

Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-01-20 22:59:02 +11:00
Ram Pai
87bbabbed8 powerpc: implementation for arch_override_mprotect_pkey()
arch independent code calls arch_override_mprotect_pkey()
to return a pkey that best matches the requested protection.

This patch provides the implementation.

Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-01-20 22:59:02 +11:00
Ram Pai
013a91b39c powerpc: ability to associate pkey to a vma
arch-independent code expects the arch to  map
a  pkey  into the vma's protection bit setting.
The patch provides that ability.

Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-01-20 22:59:01 +11:00
Ram Pai
5586cf61e1 powerpc: introduce execute-only pkey
This patch provides the implementation of execute-only pkey.
The architecture-independent layer expects the arch-dependent
layer, to support the ability to create and enable a special
key which has execute-only permission.

Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-01-20 22:59:01 +11:00
Ram Pai
06bb53b338 powerpc: store and restore the pkey state across context switches
Store and restore the AMR, IAMR and UAMOR register state of the task
before scheduling out and after scheduling in, respectively.

Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-01-20 22:59:00 +11:00
Ram Pai
2ddc53f3a7 powerpc: implementation for arch_set_user_pkey_access()
This patch provides the detailed implementation for
a user to allocate a key and enable it in the hardware.

It provides the plumbing, but it cannot be used till
the system call is implemented. The next patch  will
do so.

Reviewed-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-01-20 22:58:59 +11:00
Ram Pai
0685f217af powerpc: cleanup AMR, IAMR when a key is allocated or freed
Cleanup the bits corresponding to a key in the AMR, and IAMR
register, when the key is newly allocated/activated or is freed.
We dont want some residual bits cause the hardware enforce
unintended behavior when the key is activated or freed.

Reviewed-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-01-20 22:58:59 +11:00
Ram Pai
4fb158f65a powerpc: track allocation status of all pkeys
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.

Reviewed-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-01-20 22:58:35 +11:00
Ram Pai
92e3da3cf1 powerpc: initial pkey plumbing
Basic  plumbing  to   initialize  the   pkey  system.
Nothing is enabled yet. A later patch will enable it
once all the infrastructure is in place.

Signed-off-by: Ram Pai <linuxram@us.ibm.com>
[mpe: Rework copyrights to use SPDX tags]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-01-20 21:45:03 +11:00