Some architectures like powerpc64 have the capability to separate
read access and write access protection.
For get_user() and copy_from_user(), powerpc64 only open read access.
For put_user() and copy_to_user(), powerpc64 only open write access.
But when using unsafe_get_user() or unsafe_put_user(),
user_access_begin open both read and write.
Other architectures like powerpc book3s 32 bits only allow write
access protection. And on this architecture protection is an heavy
operation as it requires locking/unlocking per segment of 256Mbytes.
On those architecture it is therefore desirable to do the unlocking
only for write access. (Note that book3s/32 ranges from very old
powermac from the 90's with powerpc 601 processor, till modern
ADSL boxes with PowerQuicc II processors for instance so it
is still worth considering.)
In order to avoid any risk based of hacking some variable parameters
passed to user_access_begin/end that would allow hacking and
leaving user access open or opening too much, it is preferable to
use dedicated static functions that can't be overridden.
Add a user_read_access_begin and user_read_access_end to only open
read access.
Add a user_write_access_begin and user_write_access_end to only open
write access.
By default, when undefined, those new access helpers default on the
existing user_access_begin and user_access_end.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/36e43241c7f043a24b5069e78c6a7edd11043be5.1585898438.git.christophe.leroy@c-s.fr
At the time being, unsafe_copy_to_user() is based on
raw_copy_to_user() which calls __copy_tofrom_user().
__copy_tofrom_user() is a big optimised function to copy big amount
of data. It aligns destinations to cache line in order to use
dcbz instruction.
Today unsafe_copy_to_user() is called only from filldir().
It is used to mainly copy small amount of data like filenames,
so __copy_tofrom_user() is not fit.
Also, unsafe_copy_to_user() is used within user_access_begin/end
sections. In those section, it is preferable to not call functions.
Rewrite unsafe_copy_to_user() as a macro that uses __put_user_goto().
We first perform a loop of long, then we finish with necessary
complements.
unsafe_copy_to_user() might be used in the near future to copy
fixed-size data, like pt_regs structs during signal processing.
Having it as a macro allows GCC to optimise it for instead when
it knows the size in advance, it can unloop loops, drop complements
when the size is a multiple of longs, etc ...
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/fe952112c29bf6a0a2778c9e6bbb4f4afd2c4258.1587143308.git.christophe.leroy@c-s.fr
get/put_user() can be called with nontrivial arguments. fs/proc/page.c
has a good example:
if (put_user(stable_page_flags(ppage), out)) {
stable_page_flags() is quite a lot of code, including spin locks in
the page allocator.
Ensure these arguments are evaluated before user access is allowed.
This improves security by reducing code with access to userspace, but
it also fixes a PREEMPT bug with KUAP on powerpc/64s:
stable_page_flags() is currently called with AMR set to allow writes,
it ends up calling spin_unlock(), which can call preempt_schedule. But
the task switch code can not be called with AMR set (it relies on
interrupts saving the register), so this blows up.
It's fine if the code inside allow_user_access() is preemptible,
because a timer or IPI will save the AMR, but it's not okay to
explicitly cause a reschedule.
Fixes: de78a9c42a ("powerpc: Add a framework for Kernel Userspace Access Protection")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200407041245.600651-1-npiggin@gmail.com
Currently, it is possible to have CONFIG_FUNCTION_TRACER disabled, but
CONFIG_MPROFILE_KERNEL enabled. Though all existing users of
MPROFILE_KERNEL are doing the right thing, it is weird to have
MPROFILE_KERNEL enabled when the function tracer isn't. Fix this by
making MPROFILE_KERNEL depend on FUNCTION_TRACER.
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200422092612.514301-1-naveen.n.rao@linux.vnet.ibm.com
Add documentation for the following sysfs interfaces:
/sys/devices/system/cpu/cpuX/purr
/sys/devices/system/cpu/cpuX/spurr
/sys/devices/system/cpu/cpuX/idle_purr
/sys/devices/system/cpu/cpuX/idle_spurr
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1586249263-14048-6-git-send-email-ego@linux.vnet.ibm.com
On Pseries LPARs, to calculate utilization, we need to know the
[S]PURR ticks when the CPUs were busy or idle.
The total PURR and SPURR ticks are already exposed via the per-cpu
sysfs files "purr" and "spurr". This patch adds support for exposing
the idle PURR and SPURR ticks via new per-cpu sysfs files named
"idle_purr" and "idle_spurr".
This patch also adds helper functions to accurately read the values of
idle_purr and idle_spurr especially from an interrupt context between
when the interrupt has occurred between the pseries_idle_prolog() and
pseries_idle_epilog(). This will ensure that the idle purr/spurr
values corresponding to the latest idle period is accounted for before
these values are read.
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1586249263-14048-5-git-send-email-ego@linux.vnet.ibm.com
On Pseries LPARs, to calculate utilization, we need to know the
[S]PURR ticks when the CPUs were busy or idle.
Via pseries_idle_prolog(), pseries_idle_epilog(), we track the idle
PURR ticks in the VPA variable "wait_state_cycles". This patch extends
the support to account for the idle SPURR ticks.
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1586249263-14048-4-git-send-email-ego@linux.vnet.ibm.com
Currently when CPU goes idle, we take a snapshot of PURR via
pseries_idle_prolog() which is used at the CPU idle exit to compute
the idle PURR cycles via the function pseries_idle_epilog(). Thus,
the value of idle PURR cycle thus read before pseries_idle_prolog() and
after pseries_idle_epilog() is always correct.
However, if we were to read the idle PURR cycles from an interrupt
context between pseries_idle_prolog() and pseries_idle_epilog() (this
will be done in a future patch), then, the value of the idle PURR thus
read will not include the cycles spent in the most recent idle period.
Thus, in that interrupt context, we will need access to the snapshot
of the PURR before going idle, in order to compute the idle PURR
cycles for the latest idle duration.
In this patch, we save the snapshot of PURR in pseries_idle_prolog()
in a per-cpu variable, instead of on the stack, so that it can be
accessed from an interrupt context.
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1586249263-14048-3-git-send-email-ego@linux.vnet.ibm.com
Currently prior to entering an idle state on a Linux Guest, the
pseries cpuidle driver implement an idle_loop_prolog() and
idle_loop_epilog() functions which ensure that idle_purr is correctly
computed, and the hypervisor is informed that the CPU cycles have been
donated.
These prolog and epilog functions are also required in the default
idle call, i.e pseries_lpar_idle(). Hence move these accessor
functions to a common header file and call them from
pseries_lpar_idle(). Since the existing header files such as
asm/processor.h have enough clutter, create a new header file
asm/idle.h. Finally rename idle_loop_prolog() and idle_loop_epilog()
to pseries_idle_prolog() and pseries_idle_epilog() as they are only
relavent for on pseries guests.
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1586249263-14048-2-git-send-email-ego@linux.vnet.ibm.com
0day reports over and over on an powerpc randconfig with clang:
lib/mpi/generic_mpih-mul1.c:37:13: error: invalid use of a cast in a
inline asm context requiring an l-value: remove the cast or build with
-fheinous-gnu-extensions
Remove the superfluous casts, which have been done previously for x86
and arm32 in commit dea632cadd ("lib/mpi: fix build with clang") and
commit 7b7c1df288 ("lib/mpi/longlong.h: fix building with 32-bit
x86").
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://github.com/ClangBuiltLinux/linux/issues/991
Link: https://lore.kernel.org/r/20200413195041.24064-1-natechancellor@gmail.com
CONFIG_PPC_KUAP_DEBUG is not selectable because it depends on PPC_32
which doesn't exists.
Fixing it leads to a deadlock due to a vital register getting
clobbered in _switch().
Change dependency to PPC32 and use r0 instead of r4 in _switch()
Fixes: e2fb9f5444 ("powerpc/32: Prepare for Kernel Userspace Access Protection")
Cc: stable@vger.kernel.org # v5.2+
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/540242f7d4573f7cdf1b3bf46bb35f743b2cd68f.1587124651.git.christophe.leroy@c-s.fr
WRITE_RO lkdtm test works.
But when selecting CONFIG_DEBUG_RODATA_TEST, the kernel reports
rodata_test: test data was not read only
This is because when rodata test runs, there are still old entries
in TLB.
Flush TLB after setting kernel pages RO or NX.
Fixes: d5f17ee964 ("powerpc/8xx: don't disable large TLBs with CONFIG_STRICT_KERNEL_RWX")
Cc: stable@vger.kernel.org # v5.1+
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/485caac75f195f18c11eb077b0031fdd2bb7fb9e.1587361039.git.christophe.leroy@c-s.fr
allyesconfig fails with:
./usr/include/asm/vas-api.h:15:2: error: unknown type name '__u32'
15 | __u32 version;
| ^~~~~
./usr/include/asm/vas-api.h:16:2: error: unknown type name '__s16'
16 | __s16 vas_id; /* specific instance of vas or -1 for default */
| ^~~~~
./usr/include/asm/vas-api.h:17:2: error: unknown type name '__u16'
17 | __u16 reserved1;
| ^~~~~
./usr/include/asm/vas-api.h:18:2: error: unknown type name '__u64'
18 | __u64 flags; /* Future use */
| ^~~~~
./usr/include/asm/vas-api.h:19:2: error: unknown type name '__u64'
19 | __u64 reserved2[6];
| ^~~~~
uapi headers should be self contained, so add an include of
linux/types.h.
Fixes: 45f25a79fe ("powerpc/vas: Define VAS_TX_WIN_OPEN ioctl API")
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Haren Myneni <haren@linux.ibm.com>
[mpe: Flesh out change log from linux-next error report]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200422154129.11f988fd@canb.auug.org.au
Include a README file with the instructions to use the
testcases at selftests/powerpc/nx-gzip.
Signed-off-by: Bulent Abali <abali@us.ibm.com>
Signed-off-by: Raphael Moreira Zinsly <rzinsly@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200420205538.25181-6-rzinsly@linux.ibm.com
Include a decompression testcase for the powerpc NX-GZIP
engine.
Signed-off-by: Bulent Abali <abali@us.ibm.com>
Signed-off-by: Raphael Moreira Zinsly <rzinsly@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200420205538.25181-5-rzinsly@linux.ibm.com
Add files to be able to compress and decompress files using the
powerpc NX-GZIP engine.
Signed-off-by: Bulent Abali <abali@us.ibm.com>
Signed-off-by: Raphael Moreira Zinsly <rzinsly@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200420205538.25181-3-rzinsly@linux.ibm.com
As described by Haren:
Power9 processor supports Virtual Accelerator Switchboard (VAS) which
allows kernel and userspace to send compression requests to Nest
Accelerator (NX) directly. The NX unit comprises of 2 842 compression
engines and 1 GZIP engine. Linux kernel already has 842 compression
support on kernel. This patch series adds GZIP compression support
from user space. The GZIP Compression engine implements the ZLIB and
GZIP compression algorithms. No plans of adding NX-GZIP compression
support in kernel right now.
Applications can send requests to NX directly with COPY/PASTE
instructions. But kernel has to establish channel / window on NX-GZIP
device for the userspace. So userspace access to the GZIP engine is
provided through /dev/crypto/nx-gzip device with several operations.
An application must open the this device to obtain a file
descriptor (fd). Using the fd, application should issue the
VAS_TX_WIN_OPEN ioctl to establish a connection to the engine. Once
window is opened, should use mmap() system call to map the hardware
address of engine's request queue into the application's virtual
address space. Then user space forms the request as co-processor
Request Block (CRB) and paste this CRB on the mapped HW address using
COPY/PASTE instructions. Application can poll on status flags (part of
CRB) with timeout for request completion.
For VAS_TX_WIN_OPEN ioctl, if user space passes vas_id = -1 (struct
vas_tx_win_open_attr), kernel determines the VAS instance on the
corresponding chip based on the CPU on which the process is executing.
Otherwise, the specified VAS instance is used if application passes
the proper VAS instance (vas_id listed in
/proc/device-tree/vas@*/ibm,vas_id).
Process can open multiple windows with different FDs or can send
several requests to NX on the same window at the same time.
As described by Haren:
On Power9, Virtual Accelerator Switchboard (VAS) allows user space or
kernel to communicate with Nest Accelerator (NX) directly using
COPY/PASTE instructions. NX provides various functionalities such as
compression, encryption and etc. But only compression (842 and GZIP
formats) is supported in Linux kernel on power9.
842 compression driver (drivers/crypto/nx/nx-842-powernv.c) is already
included in Linux. Only GZIP support will be available from user
space.
Applications can issue GZIP compression / decompression requests to NX
with COPY/PASTE instructions. When NX is processing these requests,
can hit fault on the request buffer (not in memory). It issues an
interrupt and pastes fault CRB in fault FIFO. Expects kernel to handle
this fault and return credits for both send and fault windows after
processing.
This patch series adds IRQ and fault window setup, and NX fault
handling:
- Alloc IRQ and trigger port address, and configure IRQ per VAS
instance.
- Set port# for each window to generate an interrupt when noticed
fault.
- Set fault window and FIFO on which NX paste fault CRB.
- Setup IRQ thread fault handler per VAS instance.
- When receiving an interrupt, Read CRBs from fault FIFO and update
coprocessor_status_block (CSB) in the corresponding CRB with
translation failure (CSB_CC_TRANSLATION). After issuing NX
requests, process polls on CSB address. When it sees translation
error, can touch the request buffer to bring the page in to memory
and reissue NX request.
- If copy_to_user fails on user space CSB address, OS sends SEGV
signal.
If {i,d}-cache-block-size is set and {i,d}-cache-line-size is not, use
the block-size value for both. Per the devicetree spec cache-line-size
is only needed if it differs from the block size.
Originally the code would fallback from block size to line size. An
error message was printed if both properties were missing.
Later the code was refactored to use clearer names and logic but it
inadvertently made line size a required property, meaning on systems
without a line size property we fall back to the default from the
cputable.
On powernv (OPAL) platforms, since the introduction of device tree CPU
features (5a61ef74f2 ("powerpc/64s: Support new device tree binding
for discovering CPU features")), that has led to the wrong value being
used, as the fallback value is incorrect for Power8/Power9 CPUs.
The incorrect values flow through to the VDSO and also to the sysconf
values, SC_LEVEL1_ICACHE_LINESIZE etc.
Fixes: bd067f83b0 ("powerpc/64: Fix naming of cache block vs. cache line")
Cc: stable@vger.kernel.org # v4.11+
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Reported-by: Qian Cai <cai@lca.pw>
[mpe: Add even more detail to change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200416221908.7886-1-chris.packham@alliedtelesis.co.nz
Since cd758a9b57 "KVM: PPC: Book3S HV: Use __gfn_to_pfn_memslot in HPT
page fault handler", it's been possible in fairly rare circumstances to
load a non-present PTE in kvmppc_book3s_hv_page_fault() when running a
guest on a POWER8 host.
Because that case wasn't checked for, we could misinterpret the non-present
PTE as being a cache-inhibited PTE. That could mismatch with the
corresponding hash PTE, which would cause the function to fail with -EFAULT
a little further down. That would propagate up to the KVM_RUN ioctl()
generally causing the KVM userspace (usually qemu) to fall over.
This addresses the problem by catching that case and returning to the guest
instead.
For completeness, this fixes the radix page fault handler in the same
way. For radix this didn't cause any obvious misbehaviour, because we
ended up putting the non-present PTE into the guest's partition-scoped
page tables, leading immediately to another hypervisor data/instruction
storage interrupt, which would go through the page fault path again
and fix things up.
Fixes: cd758a9b57 "KVM: PPC: Book3S HV: Use __gfn_to_pfn_memslot in HPT page fault handler"
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1820402
Reported-by: David Gibson <david@gibson.dropbear.id.au>
Tested-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Power9 introduced Virtual Accelerator Switchboard (VAS) which allows
userspace to communicate with Nest Accelerator (NX) directly. But
kernel has to establish channel to NX for userspace. This document
describes user space API that application can use to establish
communication channel.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.ibm.com>
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1587114715.2275.1135.camel@hbabu-laptop
When window is opened, pid reference is taken for user space
windows. Not needed for kernel windows. So remove 'pid' in
vas_tx_win_attr struct.
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1587114674.2275.1132.camel@hbabu-laptop
Changes to probe GZIP device-tree nodes, open RX windows and setup
GZIP compression type. No plans to provide GZIP usage in kernel right
now, but this patch enables GZIP for user space usage.
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1587114624.2275.1129.camel@hbabu-laptop
Make setup and enable code generic to support new GZIP compression type.
Changed nx842 reference to nx and moved some code to new functions.
Functionality is not changed except sparse warning fix - setting NULL
instead of 0 for per_cpu send window in nx_delete_coprocs().
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1587114569.2275.1126.camel@hbabu-laptop
Rename nx-842-powernv.c to nx-common-powernv.c to add code for setup
and enable new GZIP compression type. The actual functionality is not
changed in this patch.
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1587114200.2275.1113.camel@hbabu-laptop
coproc entry is initialized during NX probe on power9, but not on P8.
nx842_delete_coprocs() is used for both and frees receive window if it
is allocated. Getting crash for rmmod on P8 since coproc->vas.rxwin
is not initialized.
This patch replaces kmalloc with kzalloc in nx842_powernv_probe()
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1587114163.2275.1110.camel@hbabu-laptop
On power9, userspace can send GZIP compression requests directly to NX
once kernel establishes NX channel / window with VAS. This patch provides
user space API which allows user space to establish channel using open
VAS_TX_WIN_OPEN ioctl, mmap and close operations.
Each window corresponds to file descriptor and application can open
multiple windows. After the window is opened, VAS_TX_WIN_OPEN icoctl to
open a window on specific VAS instance, mmap() system call to map
the hardware address of engine's request queue into the application's
virtual address space.
Then the application can then submit one or more requests to the the
engine by using the copy/paste instructions and pasting the CRBs to
the virtual address (aka paste_address) returned by mmap().
Only NX GZIP coprocessor type is supported right now and allow GZIP
engine access via /dev/crypto/nx-gzip device node.
Thanks to Michael Ellerman for his changes and suggestions to make the
ioctl generic to support any coprocessor type.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1587114121.2275.1109.camel@hbabu-laptop
Define the VAS_TX_WIN_OPEN ioctl interface for NX GZIP access
from user space. This interface is used to open GZIP send window and
mmap region which can be used by userspace to send requests to NX
directly with copy/paste instructions.
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1587114065.2275.1106.camel@hbabu-laptop
Initialize send and receive window attributes for GZIP high and
normal priority types.
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1587114029.2275.1103.camel@hbabu-laptop
set_thread_uses_vas() sets used_vas flag for a process that opened VAS
window and issue CP_ABORT during context switch for only that process.
In multi-thread application, windows can be shared. For example Thread
A can open a window and Thread B can run COPY/PASTE instructions to
send NX request which may cause corruption or snooping or a covert
channel Also once this flag is set, continue to run CP_ABORT even the
VAS window is closed.
So define vas-windows counter in process mm_context, increment this
counter for each window open and decrement it for window close. If
vas-windows is set, issue CP_ABORT during context switch. It means
clear the foreign real address mapping only if the process / thread
uses COPY/PASTE. Then disable it for that process if windows are not
open.
Moved set_thread_uses_vas() code to vas_tx_win_open() as this
functionality is needed only for userspace open windows. We are adding
VAS userspace support along with this fix. So no need to include this
fix in stable releases.
Fixes: 9d2a4d7133 ("powerpc: Define set_thread_uses_vas()")
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Reported-by: Nicholas Piggin <npiggin@gmail.com>
Suggested-by: Milton Miller <miltonm@us.ibm.com>
Suggested-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1587017291.2275.1077.camel@hbabu-laptop
NX may be processing requests while trying to close window. Wait until
all credits are returned and then free send window from VAS instance.
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1587017256.2275.1076.camel@hbabu-laptop
Process can not close send window until all requests are processed.
Means wait until window state is not busy and send credits are
returned. Display debug messages in case taking longer to close the
window.
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1587017219.2275.1073.camel@hbabu-laptop
System checkstops if RxFIFO overruns with more requests than the
maximum possible number of CRBs allowed in FIFO at any time. So
max credits value (rxattr.wcreds_max) is set and is passed to
vas_rx_win_open() by the the driver.
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1587017136.2275.1070.camel@hbabu-laptop
Dump FIFO entries if could not find send window and print CRB
for debugging.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1587017099.2275.1067.camel@hbabu-laptop
NX uses credit mechanism to control the number of requests issued on
a specific window at any point of time. Only send windows and fault
window are used credits. When the request is issued on a given window,
a credit is taken. This credit will be returned after that request is
processed. If credits are not available, returns RMA_Busy for send
window and RMA_Reject for fault window.
NX expects OS to return credit for send window after processing fault
CRB. Also credit has to be returned for fault window after handling
the fault.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1587017059.2275.1064.camel@hbabu-laptop
Applications polls on CSB for the status update after requests are
issued. NX process these requests and update the CSB with the status.
If it encounters translation error, pastes CRB in fault FIFO and
raises an interrupt. The kernel handles fault by reading CRB from
fault FIFO and process the fault CRB.
For each fault CRB, update fault address in CRB (fault_storage_addr)
and translation error status in CSB so that user space can touch the
fault address and resend the request. If the user space passed invalid
CSB address send signal to process with SIGSEGV.
In the case of multi-thread applications, child thread may not be
available. So if the task is not running, send signal to tgid.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1587017022.2275.1063.camel@hbabu-laptop
When NX encounters translation error on CRB and any request buffer,
raises an interrupt on the CPU to handle the fault. It can raise one
interrupt for multiple faults. Expects OS to handle these faults and
return credits for fault window after processing faults.
Setup thread IRQ handler and IRQ thread function per each VAS instance.
IRQ handler checks if the thread is already woken up and can handle new
faults. If so returns with IRQ_HANDLED, otherwise wake up thread to
process new faults.
The thread functions reads each CRB entry from fault FIFO until sees
invalid entry. After reading each CRB, determine the corresponding
send window using pswid (from CRB) and process fault CRB. Then
invalidate the entry and return credit. Processing fault CRB and
return credit is described in subsequent patches.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1587016982.2275.1060.camel@hbabu-laptop
When process opens a window, its pid and tgid will be saved in the
vas_window struct. This window will be closed when the process exits.
The kernel handles NX faults by updating CSB or send SEGV signal to pid
of the process if the userspace csb addr is invalid.
In multi-thread applications, a window can be opened by a child thread,
but it will not be closed when this thread exits. It is expected that
the parent will clean up all resources including NX windows opened by
child threads. A child thread can send NX requests using this window
and could be killed before completion is reported. If the pid assigned
to this thread is reused while requests are pending, a failure SEGV
would be directed to the wrong place.
To prevent reusing the pid, take references to pid and mm when the window
is opened and release them when when the window is closed. Then if child
thread is not running, SEGV signal will be sent to thread group leader
(tgid).
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1587016936.2275.1057.camel@hbabu-laptop
For each user space send window, register NX with fault window ID
and port value so that NX paste CRBs in this fault FIFO when it
sees fault on the request buffer.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1587016888.2275.1054.camel@hbabu-laptop
Setup fault window for each VAS instance. When NX gets a fault on
request buffer, pastes fault CRB in the corresponding fault FIFO and
then raises an interrupt to the OS. The kernel handles this fault
and process faults CRB from this FIFO.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1587016846.2275.1053.camel@hbabu-laptop
Allocate a xive irq on each chip with a vas instance. The NX coprocessor
raises a host CPU interrupt via vas if it encounters page fault on user
space request buffer. Subsequent patches register the trigger port with
the NX coprocessor, and create a vas fault handler for this interrupt
mapping.
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1587016806.2275.1050.camel@hbabu-laptop
Kernel sets fault address and status in CRB for NX page fault on user
space address after processing page fault. User space gets the signal
and handles the fault mentioned in CRB by bringing the page in to
memory and send NX request again.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1587016769.2275.1048.camel@hbabu-laptop
This function allocates IRQ on a specific chip. VAS needs per chip
IRQ allocation and will have IRQ handler per VAS instance.
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1587016720.2275.1047.camel@hbabu-laptop
When remapping a mapping where a portion of a VMA is remapped
into another portion of the VMA it can cause the VMA to become
split. During the copy_vma operation the VMA can actually
be remerged if it's an anonymous VMA whose pages have not yet
been faulted. This isn't normally a problem because at the end
of the remap the original portion is unmapped causing it to
become split again.
However, MREMAP_DONTUNMAP leaves that original portion in place which
means that the VMA which was split and then remerged is not actually
split at the end of the mremap. This patch fixes a bug where
we don't detect that the VMAs got remerged and we end up
putting back VM_ACCOUNT on the next mapping which is completely
unreleated. When that next mapping is unmapped it results in
incorrectly unaccounting for the memory which was never accounted,
and eventually we will underflow on the memory comittment.
There is also another issue which is similar, we're currently
accouting for the number of pages in the new_vma but that's wrong.
We need to account for the length of the remap operation as that's
all that is being added. If there was a mapping already at that
location its comittment would have been adjusted as part of
the munmap at the start of the mremap.
A really simple repro can be seen in:
https://gist.github.com/bgaff/e101ce99da7d9a8c60acc641d07f312c
Fixes: e346b38130 ("mm/mremap: add MREMAP_DONTUNMAP to mremap()")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Brian Geffon <bgeffon@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
clk where we want to keep it on for earlycon.
-----BEGIN PGP SIGNATURE-----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=6Qda
-----END PGP SIGNATURE-----
Merge tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux
Pull clk fixes from Stephen Boyd:
"Two build fixes for a couple clk drivers and a fix for the Unisoc
serial clk where we want to keep it on for earlycon"
* tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
clk: sprd: don't gate uart console clock
clk: mmp2: fix link error without mmp2
clk: asm9260: fix __clk_hw_register_fixed_rate_with_accuracy typo
objtool:
- Ignore the double UD2 which is emitted in BUG() when CONFIG_UBSAN_TRAP
is enabled.
- Support clang non-section symbols in objtool ORC dump
- Fix switch table detection in .text.unlikely
- Make the BP scratch register warning more robust.
x86:
- Increase microcode maximum patch size for AMD to cope with new CPUs
which have a larger patch size.
- Fix a crash in the resource control filesystem when the removal of the
default resource group is attempted.
- Preserve Code and Data Prioritization enabled state accross CPU
hotplug.
- Update split lock cpu matching to use the new X86_MATCH macros.
- Change the split lock enumeration as Intel finaly decided that the
IA32_CORE_CAPABILITIES bits are not architectural contrary to what
the SDM claims. !@#%$^!
- Add Tremont CPU models to the split lock detection cpu match.
- Add a missing static attribute to make sparse happy.
-----BEGIN PGP SIGNATURE-----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=raUm
-----END PGP SIGNATURE-----
Merge tag 'x86-urgent-2020-04-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 and objtool fixes from Thomas Gleixner:
"A set of fixes for x86 and objtool:
objtool:
- Ignore the double UD2 which is emitted in BUG() when
CONFIG_UBSAN_TRAP is enabled.
- Support clang non-section symbols in objtool ORC dump
- Fix switch table detection in .text.unlikely
- Make the BP scratch register warning more robust.
x86:
- Increase microcode maximum patch size for AMD to cope with new CPUs
which have a larger patch size.
- Fix a crash in the resource control filesystem when the removal of
the default resource group is attempted.
- Preserve Code and Data Prioritization enabled state accross CPU
hotplug.
- Update split lock cpu matching to use the new X86_MATCH macros.
- Change the split lock enumeration as Intel finaly decided that the
IA32_CORE_CAPABILITIES bits are not architectural contrary to what
the SDM claims. !@#%$^!
- Add Tremont CPU models to the split lock detection cpu match.
- Add a missing static attribute to make sparse happy"
* tag 'x86-urgent-2020-04-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/split_lock: Add Tremont family CPU models
x86/split_lock: Bits in IA32_CORE_CAPABILITIES are not architectural
x86/resctrl: Preserve CDP enable over CPU hotplug
x86/resctrl: Fix invalid attempt at removing the default resource group
x86/split_lock: Update to use X86_MATCH_INTEL_FAM6_MODEL()
x86/umip: Make umip_insns static
x86/microcode/AMD: Increase microcode PATCH_MAX_SIZE
objtool: Make BP scratch register warning more robust
objtool: Fix switch table detection in .text.unlikely
objtool: Support Clang non-section symbols in ORC generation
objtool: Support Clang non-section symbols in ORC dump
objtool: Fix CONFIG_UBSAN_TRAP unreachable warnings
Christophe Leroy