powerpc/powernv: Use struct opal_prd_msg in more places

Use the newly added struct opal_prd_msg in some other functions that
operate on opal_prd messages, rather than using other types.

Signed-off-

powerpc/powernv: Use struct opal_prd_msg in more places

Use the newly added struct opal_prd_msg in some other functions that
operate on opal_prd messages, rather than using other types.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230821142820.497107-2-mpe@ellerman.id.au

show more ...

powerpc/powernv: Fix fortify source warnings in opal-prd.c

As reported by Mahesh & Aneesh, opal_prd_msg_notifier() triggers a
FORTIFY_SOURCE warning:

memcpy: detected field-spanning write (size 3

powerpc/powernv: Fix fortify source warnings in opal-prd.c

As reported by Mahesh & Aneesh, opal_prd_msg_notifier() triggers a
FORTIFY_SOURCE warning:

memcpy: detected field-spanning write (size 32) of single field "&item->msg" at arch/powerpc/platforms/powernv/opal-prd.c:355 (size 4)
WARNING: CPU: 9 PID: 660 at arch/powerpc/platforms/powernv/opal-prd.c:355 opal_prd_msg_notifier+0x174/0x188 [opal_prd]
NIP opal_prd_msg_notifier+0x174/0x188 [opal_prd]
LR opal_prd_msg_notifier+0x170/0x188 [opal_prd]
Call Trace:
opal_prd_msg_notifier+0x170/0x188 [opal_prd] (unreliable)
notifier_call_chain+0xc0/0x1b0
atomic_notifier_call_chain+0x2c/0x40
opal_message_notify+0xf4/0x2c0

This happens because the copy is targeting item->msg, which is only 4
bytes in size, even though the enclosing item was allocated with extra
space following the msg.

To fix the warning define struct opal_prd_msg with a union of the header
and a flex array, and have the memcpy target the flex array.

Reported-by: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Reported-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Tested-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Reviewed-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230821142820.497107-1-mpe@ellerman.id.au

show more ...

powerpc/powernv/prd: Unregister OPAL_MSG_PRD2 notifier during module unload

Commit 587164cd, introduced new opal message type (OPAL_MSG_PRD2) and
added opal notifier. But I missed to unregister the

powerpc/powernv/prd: Unregister OPAL_MSG_PRD2 notifier during module unload

Commit 587164cd, introduced new opal message type (OPAL_MSG_PRD2) and
added opal notifier. But I missed to unregister the notifier during
module unload path. This results in below call trace if you try to
unload and load opal_prd module.

Also add new notifier_block for OPAL_MSG_PRD2 message.

Sample calltrace (modprobe -r opal_prd; modprobe opal_prd)
BUG: Unable to handle kernel data access on read at 0xc0080000192200e0
Faulting instruction address: 0xc00000000018d1cc
Oops: Kernel access of bad area, sig: 11 [#1]
LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA PowerNV
CPU: 66 PID: 7446 Comm: modprobe Kdump: loaded Tainted: G E 5.14.0prd #759
NIP: c00000000018d1cc LR: c00000000018d2a8 CTR: c0000000000cde10
REGS: c0000003c4c0f0a0 TRAP: 0300 Tainted: G E (5.14.0prd)
MSR: 9000000002009033 <SF,HV,VEC,EE,ME,IR,DR,RI,LE> CR: 24224824 XER: 20040000
CFAR: c00000000018d2a4 DAR: c0080000192200e0 DSISR: 40000000 IRQMASK: 1
...
NIP notifier_chain_register+0x2c/0xc0
LR atomic_notifier_chain_register+0x48/0x80
Call Trace:
0xc000000002090610 (unreliable)
atomic_notifier_chain_register+0x58/0x80
opal_message_notifier_register+0x7c/0x1e0
opal_prd_probe+0x84/0x150 [opal_prd]
platform_probe+0x78/0x130
really_probe+0x110/0x5d0
__driver_probe_device+0x17c/0x230
driver_probe_device+0x60/0x130
__driver_attach+0xfc/0x220
bus_for_each_dev+0xa8/0x130
driver_attach+0x34/0x50
bus_add_driver+0x1b0/0x300
driver_register+0x98/0x1a0
__platform_driver_register+0x38/0x50
opal_prd_driver_init+0x34/0x50 [opal_prd]
do_one_initcall+0x60/0x2d0
do_init_module+0x7c/0x320
load_module+0x3394/0x3650
__do_sys_finit_module+0xd4/0x160
system_call_exception+0x140/0x290
system_call_common+0xf4/0x258

Fixes: 587164cd593c ("powerpc/powernv: Add new opal message type")
Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211028165716.41300-1-hegdevasant@linux.vnet.ibm.com

show more ...

powerpc/powernv/prd: Unregister OPAL_MSG_PRD2 notifier during module unload

commit 52862ab33c5d97490f3fa345d6529829e6d6637b upstream.

Commit 587164cd, introduced new opal message type (OPAL_MSG_PRD

powerpc/powernv/prd: Unregister OPAL_MSG_PRD2 notifier during module unload

commit 52862ab33c5d97490f3fa345d6529829e6d6637b upstream.

Commit 587164cd, introduced new opal message type (OPAL_MSG_PRD2) and
added opal notifier. But I missed to unregister the notifier during
module unload path. This results in below call trace if you try to
unload and load opal_prd module.

Also add new notifier_block for OPAL_MSG_PRD2 message.

Sample calltrace (modprobe -r opal_prd; modprobe opal_prd)
BUG: Unable to handle kernel data access on read at 0xc0080000192200e0
Faulting instruction address: 0xc00000000018d1cc
Oops: Kernel access of bad area, sig: 11 [#1]
LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA PowerNV
CPU: 66 PID: 7446 Comm: modprobe Kdump: loaded Tainted: G E 5.14.0prd #759
NIP: c00000000018d1cc LR: c00000000018d2a8 CTR: c0000000000cde10
REGS: c0000003c4c0f0a0 TRAP: 0300 Tainted: G E (5.14.0prd)
MSR: 9000000002009033 <SF,HV,VEC,EE,ME,IR,DR,RI,LE> CR: 24224824 XER: 20040000
CFAR: c00000000018d2a4 DAR: c0080000192200e0 DSISR: 40000000 IRQMASK: 1
...
NIP notifier_chain_register+0x2c/0xc0
LR atomic_notifier_chain_register+0x48/0x80
Call Trace:
0xc000000002090610 (unreliable)
atomic_notifier_chain_register+0x58/0x80
opal_message_notifier_register+0x7c/0x1e0
opal_prd_probe+0x84/0x150 [opal_prd]
platform_probe+0x78/0x130
really_probe+0x110/0x5d0
__driver_probe_device+0x17c/0x230
driver_probe_device+0x60/0x130
__driver_attach+0xfc/0x220
bus_for_each_dev+0xa8/0x130
driver_attach+0x34/0x50
bus_add_driver+0x1b0/0x300
driver_register+0x98/0x1a0
__platform_driver_register+0x38/0x50
opal_prd_driver_init+0x34/0x50 [opal_prd]
do_one_initcall+0x60/0x2d0
do_init_module+0x7c/0x320
load_module+0x3394/0x3650
__do_sys_finit_module+0xd4/0x160
system_call_exception+0x140/0x290
system_call_common+0xf4/0x258

Fixes: 587164cd593c ("powerpc/powernv: Add new opal message type")
Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211028165716.41300-1-hegdevasant@linux.vnet.ibm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

powerpc/powernv: Remove unneeded variable: "rc"

Remove unneeded variable: "rc".

Signed-off-by: dingsenjie <dingsenjie@yulong.com>
Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>
Signed-off-by: Mi

powerpc/powernv: Remove unneeded variable: "rc"

Remove unneeded variable: "rc".

Signed-off-by: dingsenjie <dingsenjie@yulong.com>
Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210326115356.12444-1-dingsenjie@163.com

show more ...

powerpc/powernv: Fix spurious kerneldoc warnings in opal-prd.c

Comments opening with /** are parsed by kerneldoc and this causes the
following warning to be printed:

arch/powerpc/platforms/powernv

powerpc/powernv: Fix spurious kerneldoc warnings in opal-prd.c

Comments opening with /** are parsed by kerneldoc and this causes the
following warning to be printed:

arch/powerpc/platforms/powernv/opal-prd.c:31: warning: cannot understand
function prototype: 'struct opal_prd_msg_queue_item '

opal_prd_mesg_queue_item is an internal data structure so there's no real
need for it to be documented at all. Fix up the comment to squash the
warning.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200804005410.146094-5-oohall@gmail.com

show more ...

powerpc/powernv: Add new opal message type

We have OPAL_MSG_PRD message type to pass prd related messages from
OPAL to `opal-prd`. It can handle messages upto 64 bytes. We have a
requirement to send

powerpc/powernv: Add new opal message type

We have OPAL_MSG_PRD message type to pass prd related messages from
OPAL to `opal-prd`. It can handle messages upto 64 bytes. We have a
requirement to send bigger than 64 bytes of data from OPAL to
`opal-prd`. Lets add new message type (OPAL_MSG_PRD2) to pass bigger
data.

Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
[mpe: Make the error string clear that it's the PRD2 event that failed]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190826065701.8853-2-hegdevasant@linux.vnet.ibm.com

show more ...

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of th

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation this program is
distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 655 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070034.575739538@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

vfs: do bulk POLL* -> EPOLL* replacement

This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:

for V in IN OUT PRI ERR RDNORM RDBAN

vfs: do bulk POLL* -> EPOLL* replacement

This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:

for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done
done

with de-mangling cleanups yet to come.

NOTE! On almost all architectures, the EPOLL* constants have the same
values as the POLL* constants do. But they keyword here is "almost".
For various bad reasons they aren't the same, and epoll() doesn't
actually work quite correctly in some cases due to this on Sparc et al.

The next patch from Al will sort out the final differences, and we
should be all done.

Scripted-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

show more ...

ppc: annotate ->poll() instances

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

powerpc/powernv: use memdup_user

Use memdup_user() helper instead of open-coding to simplify the code.

Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Signed-off-by: Michael Ellerman <mpe@eller

powerpc/powernv: use memdup_user

Use memdup_user() helper instead of open-coding to simplify the code.

Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

show more ...

Replace <asm/uaccess.h> with <linux/uaccess.h> globally

This was entirely automated, using the script by Al:

PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
sed -i -e "s!$PA

Replace <asm/uaccess.h> with <linux/uaccess.h> globally

This was entirely automated, using the script by Al:

PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
$(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.

Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

show more ...

powerpc/powernv: Drop owner assignment from platform_driver

platform_driver does not need to set an owner because
platform_driver_register() will set it.

Signed-off-by: Krzysztof Kozlowski <k.kozlo

powerpc/powernv: Drop owner assignment from platform_driver

platform_driver does not need to set an owner because
platform_driver_register() will set it.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

show more ...

powerpc/powernv: Fix vma page prot flags in opal-prd driver

opal-prd driver will mmap() firmware code/data area as private
mapping to prd user space daemon. Write to this page will
trigger COW faul

powerpc/powernv: Fix vma page prot flags in opal-prd driver

opal-prd driver will mmap() firmware code/data area as private
mapping to prd user space daemon. Write to this page will
trigger COW faults. The new COW pages are normal kernel RAM
pages accounted by the kernel and are not special.

vma->vm_page_prot value will be used at page fault time
for the new COW pages, while pgprot_t value passed in
remap_pfn_range() is used for the initial page table entry.

Hence:
* Do not add _PAGE_SPECIAL in vma, but only for remap_pfn_range()
* Also remap_pfn_range() will add the _PAGE_SPECIAL flag using
pte_mkspecial() call, hence no need to specify in the driver

This fix resolves the page accounting warning shown below:
BUG: Bad rss-counter state mm:c0000007d34ac600 idx:1 val:19

The above warning is triggered since _PAGE_SPECIAL was incorrectly
being set for the normal kernel COW pages.

Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Acked-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

show more ...

powerpc/powernv: fix construction of opal PRD messages

We currently have a bug in the PRD code, where the contents of an
incoming message (beyond the header) will be overwritten by the list
item man

powerpc/powernv: fix construction of opal PRD messages

We currently have a bug in the PRD code, where the contents of an
incoming message (beyond the header) will be overwritten by the list
item manipulations when adding to to the prd_msg_queue.

This change reorders struct opal_prd_msg_queue_item, so that the
message body doesn't overlap the list_head.

We also clarify the memcpy of the message, as we're copying unnecessary
bytes at the end of the message data.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Acked-by: Stewart Smith <stewart@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

show more ...

powerpc/powernv: Add opal-prd channel

This change adds a char device to access the "PRD" (processor runtime
diagnostics) channel to OPAL firmware.

Includes contributions from Vaidyanathan Srinivasa

powerpc/powernv: Add opal-prd channel

This change adds a char device to access the "PRD" (processor runtime
diagnostics) channel to OPAL firmware.

Includes contributions from Vaidyanathan Srinivasan, Neelesh Gupta &
Vishal Kulkarni.

Signed-off-by: Neelesh Gupta <neelegup@linux.vnet.ibm.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Acked-by: Stewart Smith <stewart@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

show more ...

powerpc/powernv: Fix spurious kerneldoc warnings in opal-prd.c

Comments opening with /** are parsed by kerneldoc and this causes the
following warning to be printed:

arc

powerpc/powernv: Fix spurious kerneldoc warnings in opal-prd.c

Comments opening with /** are parsed by kerneldoc and this causes the
following warning to be printed:

arch/powerpc/platforms/powernv/opal-prd.c:31: warning: cannot understand
function prototype: 'struct opal_prd_msg_queue_item '

opal_prd_mesg_queue_item is an internal data structure so there's no real
need for it to be documented at all. Fix up the comment to squash the
warning.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200804005410.146094-5-oohall@gmail.com

show more ...

powerpc/powernv: Add new opal message type

We have OPAL_MSG_PRD message type to pass prd related messages from
OPAL to `opal-prd`. It can handle messages upto 64 bytes. We have a
req

powerpc/powernv: Add new opal message type

We have OPAL_MSG_PRD message type to pass prd related messages from
OPAL to `opal-prd`. It can handle messages upto 64 bytes. We have a
requirement to send bigger than 64 bytes of data from OPAL to
`opal-prd`. Lets add new message type (OPAL_MSG_PRD2) to pass bigger
data.

Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
[mpe: Make the error string clear that it's the PRD2 event that failed]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190826065701.8853-2-hegdevasant@linux.vnet.ibm.com

show more ...

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it u

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation this program is
distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 655 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070034.575739538@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

vfs: do bulk POLL* -> EPOLL* replacement

This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:

for V in IN OUT

vfs: do bulk POLL* -> EPOLL* replacement

This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:

for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done
done

with de-mangling cleanups yet to come.

NOTE! On almost all architectures, the EPOLL* constants have the same
values as the POLL* constants do. But they keyword here is "almost".
For various bad reasons they aren't the same, and epoll() doesn't
actually work quite correctly in some cases due to this on Sparc et al.

The next patch from Al will sort out the final differences, and we
should be all done.

Scripted-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

show more ...

ppc: annotate ->poll() instances

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

powerpc/powernv: use memdup_user

Use memdup_user() helper instead of open-coding to simplify the code.

Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Signed-off-by: Michael

powerpc/powernv: use memdup_user

Use memdup_user() helper instead of open-coding to simplify the code.

Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

show more ...

Replace <asm/uaccess.h> with <linux/uaccess.h> globally

This was entirely automated, using the script by Al:

PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'

Replace <asm/uaccess.h> with <linux/uaccess.h> globally

This was entirely automated, using the script by Al:

PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
$(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.

Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

show more ...

powerpc/powernv: Drop owner assignment from platform_driver

platform_driver does not need to set an owner because
platform_driver_register() will set it.

Signed-off-by: Krzyszto

powerpc/powernv: Drop owner assignment from platform_driver

platform_driver does not need to set an owner because
platform_driver_register() will set it.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

show more ...

powerpc/powernv: Fix vma page prot flags in opal-prd driver

opal-prd driver will mmap() firmware code/data area as private
mapping to prd user space daemon. Write to this page will

powerpc/powernv: Fix vma page prot flags in opal-prd driver

opal-prd driver will mmap() firmware code/data area as private
mapping to prd user space daemon. Write to this page will
trigger COW faults. The new COW pages are normal kernel RAM
pages accounted by the kernel and are not special.

vma->vm_page_prot value will be used at page fault time
for the new COW pages, while pgprot_t value passed in
remap_pfn_range() is used for the initial page table entry.

Hence:
* Do not add _PAGE_SPECIAL in vma, but only for remap_pfn_range()
* Also remap_pfn_range() will add the _PAGE_SPECIAL flag using
pte_mkspecial() call, hence no need to specify in the driver

This fix resolves the page accounting warning shown below:
BUG: Bad rss-counter state mm:c0000007d34ac600 idx:1 val:19

The above warning is triggered since _PAGE_SPECIAL was incorrectly
being set for the normal kernel COW pages.

Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Acked-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

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