Prepare to allow for hardware link stack flushing by using the
none/sw/hw type, same as the count cache state.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200609070610.846703-3-npiggin@gmail.com
The count cache flush mostly refers to both count cache and link stack
flushing. As a first step to untangling these a bit, re-name the bits
that apply to both.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200609070610.846703-2-npiggin@gmail.com
When a FP/VEC/VSX unavailable fault loads registers and enables the
facility in the MSR, re-set the lazy restore counters to 1 rather
than incrementing them so every fault gets the same number of
restores before the next fault.
This probably shouldn't be a practical change because if a lazy counter
was non-zero then it should have been restored and would not cause a
fault when userspace tries to access it. However the code and comment
implies otherwise so that's misleading and unnecessary.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200623234139.2262227-3-npiggin@gmail.com
Before returning to user, if there are missing FP/VEC/VSX bits from the
user MSR then those registers had been saved and must be restored again
before use. restore_math will decide whether to restore immediately, or
skip the restore and let fp/vec/vsx unavailable faults demand load the
registers.
Each time restore_math restores one of the FP/VSX or VEC register sets
is loaded, an 8-bit counter is incremented (load_fp and load_vec). When
these wrap to zero, restore_math no longer restores that register set
until after they are next demand faulted.
It's quite usual for those counters to have different values, so if one
wraps to zero and restore_math no longer restores its registers or user
MSR bit but the other is not zero yet does not need to be restored
(because the kernel is not frequently using the FPU), then restore_math
will be called and it will also not return in the early exit check.
This causes msr_check_and_set to test and set the MSR at every kernel
exit despite having no work to do.
This can cause workloads (e.g., a NULL syscall microbenchmark) to run
fast for a time while both counters are non-zero, then slow down when
one of the counters reaches zero, then speed up again after the second
counter reaches zero. The cost is significant, about 10% slowdown on a
NULL syscall benchmark, and the jittery behaviour is very undesirable.
Fix this by having restore_math test all conditions first, and only
update MSR if we will be loading registers.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200623234139.2262227-2-npiggin@gmail.com
The TM test in restore_math added by commit dc16b553c9 ("powerpc:
Always restore FPU/VEC/VSX if hardware transactional memory in use") is
no longer necessary after commit a8318c13e7 ("powerpc/tm: Fix
restoring FP/VMX facility incorrectly on interrupts"), which removed
the cases where restore_math has to restore if TM is active.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200623234139.2262227-1-npiggin@gmail.com
With kernel now supporting new pmem flush/sync instructions, we can now
enable the kernel to initialize the device. On P10 these devices would
appear with a new compatible string. For PAPR device we have
compatible "ibm,pmemory-v2"
and for OF pmem device we have
compatible "pmem-region-v2"
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200701072235.223558-8-aneesh.kumar@linux.ibm.com
nvdimm expect the flush routines to just mark the cache clean. The barrier
that mark the store globally visible is done in nvdimm_flush().
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200701072235.223558-7-aneesh.kumar@linux.ibm.com
pmem on POWER10 can now use phwsync instead of hwsync to ensure
all previous writes are architecturally visible for the platform
buffer flush.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200701072235.223558-6-aneesh.kumar@linux.ibm.com
Start using dcbstps; phwsync; sequence for flushing persistent memory range.
The new instructions are implemented as a variant of dcbf and hwsync and on
P8 and P9 they will be executed as those instructions. We avoid using them on
older hardware. This helps to avoid difficult to debug bugs.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200701072235.223558-4-aneesh.kumar@linux.ibm.com
POWER10 introduces two new variants of dcbf instructions (dcbstps and dcbfps)
that can be used to write modified locations back to persistent storage.
Additionally, POWER10 also introduce phwsync and plwsync which can be used
to establish order of these writes to persistent storage.
This patch exposes these instructions to the rest of the kernel. The existing
dcbf and hwsync instructions in P8 and P9 are adequate to enable appropriate
synchronization with OpenCAPI-hosted persistent storage. Hence the new
instructions are added as a variant of the old ones that old hardware
won't differentiate.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200701072235.223558-3-aneesh.kumar@linux.ibm.com
The PAPR based virtualized persistent memory devices are only supported on
POWER9 and above. In the followup patch, the kernel will switch the persistent
memory cache flush functions to use a new `dcbf` variant instruction. The new
instructions even though added in ISA 3.1 works even on P8 and P9 because these
are implemented as a variant of existing `dcbf` and `hwsync` and on P8 and
P9 behaves as such.
Considering these devices are only supported on P8 and above, update the driver
to prevent a P7-compat guest from using persistent memory devices.
We don't update of_pmem driver with the same condition, because, on bare-metal,
the firmware enables pmem support only on P9 and above. There the kernel depends
on OPAL firmware to restrict exposing persistent memory related device tree
entries on older hardware. of_pmem.ko is written without any arch dependency and
we don't want to add ppc64 specific cpu feature check in of_pmem driver.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200701072235.223558-2-aneesh.kumar@linux.ibm.com
When platform doesn't support GTSE, let TLB invalidation requests
for radix guests be off-loaded to the host using H_RPT_INVALIDATE
hcall.
[hcall wrapper, error path handling and renames]
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Bharata B Rao <bharata@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200703053608.12884-4-bharata@linux.ibm.com
H_REGISTER_PROC_TBL asks for GTSE by default. GTSE flag bit should
be set only when GTSE is supported.
Signed-off-by: Bharata B Rao <bharata@linux.ibm.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200703053608.12884-3-bharata@linux.ibm.com
Make GTSE an MMU feature and enable it by default for radix.
However for guest, conditionally enable it if hypervisor supports
it via OV5 vector. Let prom_init ask for radix GTSE only if the
support exists.
Having GTSE as an MMU feature will make it easy to enable radix
without GTSE. Currently radix assumes GTSE is enabled by default.
Signed-off-by: Bharata B Rao <bharata@linux.ibm.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200703053608.12884-2-bharata@linux.ibm.com
save_general_regs() which does special handling when i == PT_SOFTE.
Rewrite it to minimise the specific part, especially the __put_user()
and associated error handling is the same so make it common.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
[mpe: Use a regular if rather than ternary operator]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/47a38df46cae5a5a88a558a64d71f75e9c4d9950.1594125164.git.christophe.leroy@csgroup.eu
Since commit ("1bd79336a426 powerpc: Fix various
syscall/signal/swapcontext bugs"), getting save_general_regs() called
without FULL_REGS() is very unlikely and generates a warning.
The 32-bit version of save_general_regs() doesn't take care of it
at all and copies all registers anyway since that commit.
Moreover, commit 965dd3ad30 ("powerpc/64/syscall: Remove
non-volatile GPR save optimisation") is another reason why it would
never happen.
So the same with 64-bit, don't worry about FULL_REGS() and copy
all registers all the time.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/173de3b659fa3a5f126a0eb170522cccd909950f.1594125164.git.christophe.leroy@csgroup.eu
Returning from an interrupt or syscall to a signal handler currently
begins execution directly at the handler's entry point, with LR set to
the address of the sigreturn trampoline. When the signal handler
function returns, it runs the trampoline. It looks like this:
# interrupt at user address xyz
# kernel stuff... signal is raised
rfid
# void handler(int sig)
addis 2,12,.TOC.-.LCF0@ha
addi 2,2,.TOC.-.LCF0@l
mflr 0
std 0,16(1)
stdu 1,-96(1)
# handler stuff
ld 0,16(1)
mtlr 0
blr
# __kernel_sigtramp_rt64
addi r1,r1,__SIGNAL_FRAMESIZE
li r0,__NR_rt_sigreturn
sc
# kernel executes rt_sigreturn
rfid
# back to user address xyz
Note the blr with no matching bl. This can corrupt the return
predictor.
Solve this by instead resuming execution at the signal trampoline
which then calls the signal handler. qtrace-tools link_stack checker
confirms the entire user/kernel/vdso cycle is balanced after this
patch, whereas it's not upstream.
Alan confirms the dwarf unwind info still looks good. gdb still
recognises the signal frame and can step into parent frames if it
break inside a signal handler.
Performance is pretty noisy, not a very significant change on a POWER9
here, but branch misses are consistently a lot lower on a
microbenchmark:
Performance counter stats for './signal':
13,085.72 msec task-clock # 1.000 CPUs utilized
45,024,760,101 cycles # 3.441 GHz
65,102,895,542 instructions # 1.45 insn per cycle
11,271,673,787 branches # 861.372 M/sec
59,468,979 branch-misses # 0.53% of all branches
12,989.09 msec task-clock # 1.000 CPUs utilized
44,692,719,559 cycles # 3.441 GHz
65,109,984,964 instructions # 1.46 insn per cycle
11,282,136,057 branches # 868.585 M/sec
39,786,942 branch-misses # 0.35% of all branches
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200511101952.1463138-1-npiggin@gmail.com
The kernel test robot pointed out a slightly different error message
after recent commit 5456ffdee6 ("powerpc/spufs: simplify spufs core
dumping") to spufs for a configuration that never worked:
powerpc64-linux-ld: arch/powerpc/platforms/cell/spufs/file.o: in function `.spufs_proxydma_info_dump':
>> file.c:(.text+0x4c68): undefined reference to `.dump_emit'
powerpc64-linux-ld: arch/powerpc/platforms/cell/spufs/file.o: in function `.spufs_dma_info_dump':
file.c:(.text+0x4d70): undefined reference to `.dump_emit'
powerpc64-linux-ld: arch/powerpc/platforms/cell/spufs/file.o: in function `.spufs_wbox_info_dump':
file.c:(.text+0x4df4): undefined reference to `.dump_emit'
Add a Kconfig dependency to prevent this from happening again.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200706132302.3885935-1-arnd@arndb.de
pnv_ioda_setup_bus_dma() is only used when a passed through PE is
returned to the host. If the kernel is built without IOMMU support
this is dead code. Move it under the #ifdef with the rest of the
IOMMU API support.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200705133557.443607-2-oohall@gmail.com
The kernel test robot noticed these are non-static which causes Clang to
print some warnings. These are called via ppc_md function pointers so
there's no need for them to be non-static.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200705133557.443607-1-oohall@gmail.com
Unlike drivers/base/cacheinfo, powerpc cacheinfo code is not exposing
shared_cpu_list under /sys/devices/system/cpu/cpu<n>/cache/index<m>
Add shared_cpu_list to per cpu per index directory to maintain parity
with x86. Some scripts (example: mmtests
https://github.com/gormanm/mmtests) seem to be looking for
shared_cpu_list instead of shared_cpu_map.
Before this patch:
# ls /sys/devices/system/cpu0/cache/index1
coherency_line_size number_of_sets size ways_of_associativity
level shared_cpu_map type
# cat /sys/devices/system/cpu0/cache/index1/shared_cpu_map
00ff
#
After this patch:
# ls /sys/devices/system/cpu0/cache/index1
coherency_line_size number_of_sets shared_cpu_map type
level shared_cpu_list size ways_of_associativity
# cat /sys/devices/system/cpu0/cache/index1/shared_cpu_map
00ff
# cat /sys/devices/system/cpu0/cache/index1/shared_cpu_list
0-7
#
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200629103703.4538-4-srikar@linux.vnet.ibm.com
In anticipation of implementing shared_cpu_list, move code under
shared_cpu_map_show() to a common function.
No functional changes.
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200629103703.4538-3-srikar@linux.vnet.ibm.com
Tejun Heo had modified shared_cpu_map_show() to use scnprintf instead
of cpumap_print during support for *pb[l] format. Refer commit
0c118b7bd0 ("powerpc: use %*pb[l] to print bitmaps including
cpumasks and nodemasks").
cpumap_print_to_pagebuf() is a standard function to print cpumap. With
commit 9cf79d115f ("bitmap: remove explicit newline handling using
scnprintf format string"), there is no need to print explicit newline
and trailing null character. cpumap_print_to_pagebuf() internally uses
scnprintf(). Hence replace scnprintf() with cpumap_print_to_pagebuf().
Note: shared_cpu_map_show() in drivers/base/cacheinfo.c already uses
cpumap_print_to_pagebuf().
Before this patch:
# cat /sys/devices/system/cpu0/cache/index1/shared_cpu_map
00ff
#
(Notice the extra blank line).
After this patch:
# cat /sys/devices/system/cpu0/cache/index1/shared_cpu_map
00ff
#
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200629103703.4538-2-srikar@linux.vnet.ibm.com
I'm seeing RCU warnings when exiting xmon. xmon resets the NMI
watchdog, but does nothing with the RCU stall or soft lockup
watchdogs. Add a helper function that handles all three.
Signed-off-by: Anton Blanchard <anton@ozlabs.org>
Acked-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200630100218.62a3c3fb@kryten.localdomain
With CONFIG_OF_ALL_DTBS=y, as set by eg. allmodconfig, we see lots of
warnings about our dts files, such as:
arch/powerpc/boot/dts/glacier.dts:492.26-532.5:
Warning (pci_bridge): /plb/pciex@d00000000: node name is not "pci"
or "pcie"
The node name should not particularly matter, it's just a name, and
AFAICS there's no kernel code that cares whether nodes are *named*
"pciex" or "pcie". So shutup these warnings by converting to the name
dtc wants.
As always there's some risk this could break something obscure that
does rely on the name, in which case we can revert.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200623130320.405852-1-mpe@ellerman.id.au
Clang warns:
arch/powerpc/boot/main.c:107:18: warning: array comparison always
evaluates to a constant [-Wtautological-compare]
if (_initrd_end > _initrd_start) {
^
arch/powerpc/boot/main.c:155:20: warning: array comparison always
evaluates to a constant [-Wtautological-compare]
if (_esm_blob_end <= _esm_blob_start)
^
2 warnings generated.
These are not true arrays, they are linker defined symbols, which are
just addresses. Using the address of operator silences the warning
and does not change the resulting assembly with either clang/ld.lld
or gcc/ld (tested with diff + objdump -Dr).
Reported-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Geoff Levand <geoff@infradead.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200624035920.835571-1-natechancellor@gmail.com
Move ptep_get() close to pte_update(), in an ifdef section already
dedicated to powerpc 8xx. This section contains explanation about
the layout of page table entries.
Also modify it to return 4 times the pte value instead of padding
with zeroes.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/9f2df6621fcaf9eba15fadc61c169d0c8e2fb849.1592481938.git.christophe.leroy@csgroup.eu
With hash translation, the hypervisor can hint the LPAR about 16GB contiguous range
via ibm,expected#pages. The kernel marks the range specified in the device tree
as reserved. Avoid doing this when using radix translation. Radix translation
only supports 1G gigantic hugepage and kernel can do the 1G gigantic hugepage
allocation via early memblock reservation. This can be done because with radix
translation pages are not required to be contiguous on the host.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200622064019.16682-1-aneesh.kumar@linux.ibm.com
FIX_EARLY_DEBUG_BASE reserves a 128k area for debuging.
When page size is 256k, the calculation results in a 0 number of
pages, leading to the following failure:
CC arch/powerpc/kernel/asm-offsets.s
In file included from ./arch/powerpc/include/asm/nohash/32/pgtable.h:77:0,
from ./arch/powerpc/include/asm/nohash/pgtable.h:8,
from ./arch/powerpc/include/asm/pgtable.h:20,
from ./include/linux/pgtable.h:6,
from ./arch/powerpc/include/asm/kup.h:42,
from ./arch/powerpc/include/asm/uaccess.h:9,
from ./include/linux/uaccess.h:11,
from ./include/linux/crypto.h:21,
from ./include/crypto/hash.h:11,
from ./include/linux/uio.h:10,
from ./include/linux/socket.h:8,
from ./include/linux/compat.h:15,
from arch/powerpc/kernel/asm-offsets.c:14:
./arch/powerpc/include/asm/fixmap.h:75:2: error: overflow in enumeration values
__end_of_permanent_fixed_addresses,
^
make[2]: *** [arch/powerpc/kernel/asm-offsets.s] Error 1
Ensure the debug area is at least one page.
Fixes: b8e8efaa86 ("powerpc: reserve fixmap entries for early debug")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/ca8c9f8249f523b1fab873e67b81b11989d46553.1592207216.git.christophe.leroy@csgroup.eu
The iommu_table_ops::xchg_no_kill() callback updates TCE. It is quite
possible that not entire table is allocated if it is huge and multilevel
so xchg may also allocate subtables. If failed, it returns H_HARDWARE
for failed allocation and H_TOO_HARD if it needs it but cannot do because
the alloc parameter is "false" (set when called with MMU=off to force
retry with MMU=on).
The problem is that having separate errors only matters in real mode
(MMU=off) but the only caller with alloc="false" does not check the exact
error code and simply returns H_TOO_HARD; and for every other mode
alloc is "true". Also, the function is also called from the ioctl()
handler of the VFIO SPAPR TCE IOMMU subdriver which does not expect
hypervisor error codes (H_xxx) and will expose them to the userspace.
This converts wrong error codes to -ENOMEM.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200617003835.48831-1-aik@ozlabs.ru
IS_ENABLED() matches names exactly, so the missing "CONFIG_" prefix
means this code would never be built.
Also fixes a missing newline in pr_warn().
Fixes: 970d54f99c ("powerpc/book3s64/hash: Disable 16M linear mapping size if not aligned")
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/202006050717.A2F9809E@keescook
Since commit cbe46bd4f5 ("powerpc: remove CONFIG_CMDLINE #ifdef mess")
CONFIG_CMDLINE has always had a value regardless of CONFIG_CMDLINE_BOOL.
For example:
$ make ARCH=powerpc defconfig
$ cat .config
# CONFIG_CMDLINE_BOOL is not set
CONFIG_CMDLINE=""
When enabling CONFIG_CMDLINE_BOOL this value is kept making the 'default
"..." if CONFIG_CMDLINE_BOOL' ineffective.
$ ./scripts/config --enable CONFIG_CMDLINE_BOOL
$ cat .config
CONFIG_CMDLINE_BOOL=y
CONFIG_CMDLINE=""
Remove CONFIG_CMDLINE_BOOL and the inaccessible default.
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200611224220.25066-2-chris.packham@alliedtelesis.co.nz
blrl is not recommended to use as an indirect function call, as it may
corrupt the link stack predictor.
This is not a performance critical path but this should be fixed for
consistency.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200611121119.1015740-1-npiggin@gmail.com
One fix for the interrupt rework we did last release which broke KVM-PR.
Three commits fixing some fallout from the READ_ONCE() changes interacting badly
with our 8xx 16K pages support, which uses a pte_t that is a structure of 4
actual PTEs.
A cleanup of the 8xx pte_update() to use the newly added pmd_off().
A fix for a crash when handling an oops if CONFIG_DEBUG_VIRTUAL is enabled.
A minor fix for the SPU syscall generation.
Thanks to:
Aneesh Kumar K.V, Christian Zigotzky, Christophe Leroy, Mike Rapoport,
Nicholas Piggin.
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Merge tag 'powerpc-5.8-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc fixes from Michael Ellerman:
- One fix for the interrupt rework we did last release which broke
KVM-PR
- Three commits fixing some fallout from the READ_ONCE() changes
interacting badly with our 8xx 16K pages support, which uses a pte_t
that is a structure of 4 actual PTEs
- A cleanup of the 8xx pte_update() to use the newly added pmd_off()
- A fix for a crash when handling an oops if CONFIG_DEBUG_VIRTUAL is
enabled
- A minor fix for the SPU syscall generation
Thanks to Aneesh Kumar K.V, Christian Zigotzky, Christophe Leroy, Mike
Rapoport, Nicholas Piggin.
* tag 'powerpc-5.8-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
powerpc/8xx: Provide ptep_get() with 16k pages
mm: Allow arches to provide ptep_get()
mm/gup: Use huge_ptep_get() in gup_hugepte()
powerpc/syscalls: Use the number when building SPU syscall table
powerpc/8xx: use pmd_off() to access a PMD entry in pte_update()
powerpc/64s: Fix KVM interrupt using wrong save area
powerpc: Fix kernel crash in show_instructions() w/DEBUG_VIRTUAL
- Fix the visibility of the region 'align' attribute. The new unit tests
for region alignment handling caught a corner case where the alignment
cannot be specified if the region is converted from static to dynamic
provisioning at runtime.
- Add support for device health retrieval for the persistent memory
supported by the papr_scm driver. This includes both the standard
sysfs "health flags" that the nfit persistent memory driver publishes
and a mechanism for the ndctl tool to retrieve a health-command payload.
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Merge tag 'libnvdimm-for-5.8-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
Pull libnvdimm updates from Dan Williams:
"A feature (papr_scm health retrieval) and a fix (sysfs attribute
visibility) for v5.8.
Vaibhav explains in the merge commit below why missing v5.8 would be
painful and I agreed to try a -rc2 pull because only cosmetics kept
this out of -rc1 and his initial versions were posted in more than
enough time for v5.8 consideration:
'These patches are tied to specific features that were committed to
customers in upcoming distros releases (RHEL and SLES) whose
time-lines are tied to 5.8 kernel release.
Being able to track the health of an nvdimm is critical for our
customers that are running workloads leveraging papr-scm nvdimms.
Missing the 5.8 kernel would mean missing the distro timelines and
shifting forward the availability of this feature in distro kernels
by at least 6 months'
Summary:
- Fix the visibility of the region 'align' attribute.
The new unit tests for region alignment handling caught a corner
case where the alignment cannot be specified if the region is
converted from static to dynamic provisioning at runtime.
- Add support for device health retrieval for the persistent memory
supported by the papr_scm driver.
This includes both the standard sysfs "health flags" that the nfit
persistent memory driver publishes and a mechanism for the ndctl
tool to retrieve a health-command payload"
* tag 'libnvdimm-for-5.8-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
nvdimm/region: always show the 'align' attribute
powerpc/papr_scm: Implement support for PAPR_PDSM_HEALTH
ndctl/papr_scm,uapi: Add support for PAPR nvdimm specific methods
powerpc/papr_scm: Improve error logging and handling papr_scm_ndctl()
powerpc/papr_scm: Fetch nvdimm health information from PHYP
seq_buf: Export seq_buf_printf
powerpc: Document details on H_SCM_HEALTH hcall
READ_ONCE() now enforces atomic read, which leads to:
CC mm/gup.o
In file included from ./include/linux/kernel.h:11:0,
from mm/gup.c:2:
In function 'gup_hugepte.constprop',
inlined from 'gup_huge_pd.isra.79' at mm/gup.c:2465:8:
./include/linux/compiler.h:392:38: error: call to '__compiletime_assert_222' declared with attribute error: Unsupported access size for {READ,WRITE}_ONCE().
_compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
^
./include/linux/compiler.h:373:4: note: in definition of macro '__compiletime_assert'
prefix ## suffix(); \
^
./include/linux/compiler.h:392:2: note: in expansion of macro '_compiletime_assert'
_compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
^
./include/linux/compiler.h:405:2: note: in expansion of macro 'compiletime_assert'
compiletime_assert(__native_word(t) || sizeof(t) == sizeof(long long), \
^
./include/linux/compiler.h:291:2: note: in expansion of macro 'compiletime_assert_rwonce_type'
compiletime_assert_rwonce_type(x); \
^
mm/gup.c:2428:8: note: in expansion of macro 'READ_ONCE'
pte = READ_ONCE(*ptep);
^
In function 'gup_get_pte',
inlined from 'gup_pte_range' at mm/gup.c:2228:9,
inlined from 'gup_pmd_range' at mm/gup.c:2613:15,
inlined from 'gup_pud_range' at mm/gup.c:2641:15,
inlined from 'gup_p4d_range' at mm/gup.c:2666:15,
inlined from 'gup_pgd_range' at mm/gup.c:2694:15,
inlined from 'internal_get_user_pages_fast' at mm/gup.c:2795:3:
./include/linux/compiler.h:392:38: error: call to '__compiletime_assert_219' declared with attribute error: Unsupported access size for {READ,WRITE}_ONCE().
_compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
^
./include/linux/compiler.h:373:4: note: in definition of macro '__compiletime_assert'
prefix ## suffix(); \
^
./include/linux/compiler.h:392:2: note: in expansion of macro '_compiletime_assert'
_compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
^
./include/linux/compiler.h:405:2: note: in expansion of macro 'compiletime_assert'
compiletime_assert(__native_word(t) || sizeof(t) == sizeof(long long), \
^
./include/linux/compiler.h:291:2: note: in expansion of macro 'compiletime_assert_rwonce_type'
compiletime_assert_rwonce_type(x); \
^
mm/gup.c:2199:9: note: in expansion of macro 'READ_ONCE'
return READ_ONCE(*ptep);
^
make[2]: *** [mm/gup.o] Error 1
Define ptep_get() on 8xx when using 16k pages.
Fixes: 9e343b467c ("READ_ONCE: Enforce atomicity for {READ,WRITE}_ONCE() memory accesses")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/341688399c1b102756046d19ea6ce39db1ae4742.1592225558.git.christophe.leroy@csgroup.eu
Now that we've renamed probe_kernel_address() to get_kernel_nofault()
and made it look and behave more in line with get_user(), some of the
subtle type behavior differences end up being more obvious and possibly
dangerous.
When you do
get_user(val, user_ptr);
the type of the access comes from the "user_ptr" part, and the above
basically acts as
val = *user_ptr;
by design (except, of course, for the fact that the actual dereference
is done with a user access).
Note how in the above case, the type of the end result comes from the
pointer argument, and then the value is cast to the type of 'val' as
part of the assignment.
So the type of the pointer is ultimately the more important type both
for the access itself.
But 'get_kernel_nofault()' may now _look_ similar, but it behaves very
differently. When you do
get_kernel_nofault(val, kernel_ptr);
it behaves like
val = *(typeof(val) *)kernel_ptr;
except, of course, for the fact that the actual dereference is done with
exception handling so that a faulting access is suppressed and returned
as the error code.
But note how different the casting behavior of the two superficially
similar accesses are: one does the actual access in the size of the type
the pointer points to, while the other does the access in the size of
the target, and ignores the pointer type entirely.
Actually changing get_kernel_nofault() to act like get_user() is almost
certainly the right thing to do eventually, but in the meantime this
patch adds logit to at least verify that the pointer type is compatible
with the type of the result.
In many cases, this involves just casting the pointer to 'void *' to
make it obvious that the type of the pointer is not the important part.
It's not how 'get_user()' acts, but at least the behavioral difference
is now obvious and explicit.
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
