Add tracepoint to track hugepage invalidate. This help us
in debugging difficult to track bugs.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
We would get wrong results in compiler recomputed old_pmd. Avoid
that by using ACCESS_ONCE
CC: <stable@vger.kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
As per ISA, for 4k base page size we compare 14..65 bits of VA specified
with the entry_VA in tlb. That implies we need to make sure we do a
tlbie with all the possible 4k va we used to access the 16MB hugepage.
With 64k base page size we compare 14..57 bits of VA. Hence we cannot
ignore the lower 24 bits of va while tlbie .We also cannot tlb
invalidate a 16MB entry with just one tlbie instruction because
we don't track which va was used to instantiate the tlb entry.
CC: <stable@vger.kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
If we changed base page size of the segment, either via sub_page_protect
or via remap_4k_pfn, we do a demote_segment which doesn't flush the hash
table entries. We do a lazy hash page table flush for all mapped pages
in the demoted segment. This happens when we handle hash page fault for
these pages.
We use _PAGE_COMBO bit along with _PAGE_HASHPTE to indicate whether a
pte is backed by 4K hash pte. If we find _PAGE_COMBO not set on the pte,
that implies that we could possibly have older 64K hash pte entries in
the hash page table and we need to invalidate those entries.
Use _PAGE_COMBO to determine the page size with which we should
invalidate the hash table entries on unmap.
CC: <stable@vger.kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
If we changed base page size of the segment, either via sub_page_protect
or via remap_4k_pfn, we do a demote_segment which doesn't flush the hash
table entries. We do a lazy hash page table flush for all mapped pages
in the demoted segment. This happens when we handle hash page fault
for these pages.
We use _PAGE_COMBO bit along with _PAGE_HASHPTE to indicate whether a
pte is backed by 4K hash pte. If we find _PAGE_COMBO not set on the pte,
that implies that we could possibly have older 64K hash pte entries in
the hash page table and we need to invalidate those entries.
Handle this correctly for 16M pages
CC: <stable@vger.kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
The segment identifier and segment size will remain the same in
the loop, So we can compute it outside. We also change the
hugepage_invalidate interface so that we can use it the later patch
CC: <stable@vger.kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
With hugepages, we store the hpte valid information in the pte page
whose address is stored in the second half of the PMD. Use a
write barrier to make sure clearing pmd busy bit and updating
hpte valid info are ordered properly.
CC: <stable@vger.kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
There is an issue currently where NUMA information is used on powerpc
(and possibly ia64) before it has been read from the device-tree, which
leads to large slab consumption with CONFIG_SLUB and memoryless nodes.
NUMA powerpc non-boot CPU's cpu_to_node/cpu_to_mem is only accurate
after start_secondary(), similar to ia64, which is invoked via
smp_init().
Commit 6ee0578b4d ("workqueue: mark init_workqueues() as
early_initcall()") made init_workqueues() be invoked via
do_pre_smp_initcalls(), which is obviously before the secondary
processors are online.
Additionally, the following commits changed init_workqueues() to use
cpu_to_node to determine the node to use for kthread_create_on_node:
bce903809a ("workqueue: add wq_numa_tbl_len and
wq_numa_possible_cpumask[]")
f3f90ad469 ("workqueue: determine NUMA node of workers accourding to
the allowed cpumask")
Therefore, when init_workqueues() runs, it sees all CPUs as being on
Node 0. On LPARs or KVM guests where Node 0 is memoryless, this leads to
a high number of slab deactivations
(http://www.spinics.net/lists/linux-mm/msg67489.html).
Fix this by initializing the powerpc-specific CPU<->node/local memory
node mapping as early as possible, which on powerpc is
do_init_bootmem(). Currently that function initializes the mapping for
the boot CPU, but we extend it to setup the mapping for all possible
CPUs. Then, in smp_prepare_cpus(), we can correspondingly set the
per-cpu values for all possible CPUs. That ensures that before the
early_initcalls run (and really as early as possible), the per-cpu NUMA
mapping is accurate.
While testing memoryless nodes on PowerKVM guests with a fix to the
workqueue logic to use cpu_to_mem() instead of cpu_to_node(), with a
guest topology of:
available: 2 nodes (0-1)
node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49
node 0 size: 0 MB
node 0 free: 0 MB
node 1 cpus: 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99
node 1 size: 16336 MB
node 1 free: 15329 MB
node distances:
node 0 1
0: 10 40
1: 40 10
the slab consumption decreases from
Slab: 932416 kB
SUnreclaim: 902336 kB
to
Slab: 395264 kB
SUnreclaim: 359424 kB
And we a corresponding increase in the slab efficiency from
slab mem objs slabs
used active active
------------------------------------------------------------
kmalloc-16384 337 MB 11.28% 100.00%
task_struct 288 MB 9.93% 100.00%
to
slab mem objs slabs
used active active
------------------------------------------------------------
kmalloc-16384 37 MB 100.00% 100.00%
task_struct 31 MB 100.00% 100.00%
Powerpc didn't support memoryless nodes until recently (64bb80d87f
"powerpc/numa: Enable CONFIG_HAVE_MEMORYLESS_NODES" and 8c27226119
"powerpc/numa: Enable USE_PERCPU_NUMA_NODE_ID"). Those commits also
helped improve memory consumption with these kind of environments.
Signed-off-by: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
__early_init_mmu() does some things that are really only needed by the
boot cpu. On FSL booke, This includes calling
memblock_enforce_memory_limit(), which is labelled __init. Secondary
cpu init code can't be __init as that would break CPU hotplug.
While it's probably a bug that memblock_enforce_memory_limit() isn't
__init_memblock instead, there's no reason why we should be doing this
stuff for secondary cpus in the first place.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Rather than have architectures #define ARCH_HAS_SG_CHAIN in an
architecture specific scatterlist.h, make it a proper Kconfig option and
use that instead. At same time, remove the header files are are now
mostly useless and just include asm-generic/scatterlist.h.
[sfr@canb.auug.org.au: powerpc files now need asm/dma.h]
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de> [x86]
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> [powerpc]
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull powerpc updates from Ben Herrenschmidt:
"This is the powerpc new goodies for 3.17. The short story:
The biggest bit is Michael removing all of pre-POWER4 processor
support from the 64-bit kernel. POWER3 and rs64. This gets rid of a
ton of old cruft that has been bitrotting in a long while. It was
broken for quite a few versions already and nobody noticed. Nobody
uses those machines anymore. While at it, he cleaned up a bunch of
old dusty cabinets, getting rid of a skeletton or two.
Then, we have some base VFIO support for KVM, which allows assigning
of PCI devices to KVM guests, support for large 64-bit BARs on
"powernv" platforms, support for HMI (Hardware Management Interrupts)
on those same platforms, some sparse-vmemmap improvements (for memory
hotplug),
There is the usual batch of Freescale embedded updates (summary in the
merge commit) and fixes here or there, I think that's it for the
highlights"
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (102 commits)
powerpc/eeh: Export eeh_iommu_group_to_pe()
powerpc/eeh: Add missing #ifdef CONFIG_IOMMU_API
powerpc: Reduce scariness of interrupt frames in stack traces
powerpc: start loop at section start of start in vmemmap_populated()
powerpc: implement vmemmap_free()
powerpc: implement vmemmap_remove_mapping() for BOOK3S
powerpc: implement vmemmap_list_free()
powerpc: Fail remap_4k_pfn() if PFN doesn't fit inside PTE
powerpc/book3s: Fix endianess issue for HMI handling on napping cpus.
powerpc/book3s: handle HMIs for cpus in nap mode.
powerpc/powernv: Invoke opal call to handle hmi.
powerpc/book3s: Add basic infrastructure to handle HMI in Linux.
powerpc/iommu: Fix comments with it_page_shift
powerpc/powernv: Handle compound PE in config accessors
powerpc/powernv: Handle compound PE for EEH
powerpc/powernv: Handle compound PE
powerpc/powernv: Split ioda_eeh_get_state()
powerpc/powernv: Allow to freeze PE
powerpc/powernv: Enable M64 aperatus for PHB3
powerpc/eeh: Aux PE data for error log
...
This patch introduces zone_for_memory() to arch_add_memory() on powerpc
to ensure new, higher memory added into ZONE_MOVABLE if movable zone has
already setup.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: "Mel Gorman" <mgorman@suse.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
vmemmap_populated() checks whether the [start, start + page_size) has valid
pfn numbers, to know whether a vmemmap mapping has been created that includes
this range.
Some range before end might not be checked by this loop:
sec11start......start11..sec11end/sec12start..end....start12..sec12end
as the above, for start11(section 11), it checks [sec11start, sec11end), and
loop ends as the next start(start12) is bigger than end. However,
[sec11end/sec12start, end) is not checked here.
So before the loop, adjust the start to be the start of the section, so we don't miss ranges like the above.
After we adjust start to be the start of the section, it also means it's
aligned with vmemmap as of the sizeof struct page, so we could use
page_to_pfn directly in the loop.
Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Acked-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
vmemmap_free() does the opposite of vmemap_populate().
This patch also puts vmemmap_free() and vmemmap_list_free() into
CONFIG_MEMMORY_HOTPLUG.
Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Acked-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This is to be called in vmemmap_free(), leave the implementation on BOOK3E
empty as before.
Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Acked-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This patch implements vmemmap_list_free() for vmemmap_free().
The freed entries will be removed from vmemmap_list, and form a freed list,
with next as the header. The next position in the last allocated page is kept
at the list tail.
When allocation, if there are freed entries left, get it from the freed list;
if no freed entries left, get it like before from the last allocated pages.
With this change, realmode_pfn_to_page() also needs to be changed to walk
all the entries in the vmemmap_list, as the virt_addr of the entries might not
be stored in order anymore.
It helps to reuse the memory when continuous doing memory hot-plug/remove
operations, but didn't reclaim the pages already allocated, so the memory usage
will only increase, but won't exceed the value for the largest memory
configuration.
Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Acked-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This silences a section mismatch warning. early_alloc_pgtable() is
called from map_kernel_page() which cannot be __init, but only when
slab_is_available() returns false which can only happen during early
boot.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Scott writes:
Highlights include e6500 hardware threading support, an e6500 TLB erratum
workaround, corenet error reporting, support for a new board, and some
minor fixes.
Erratum A-008139 can cause duplicate TLB entries if an indirect
entry is overwritten using tlbwe while the other thread is using it to
do a lookup. Work around this by using tlbilx to invalidate prior
to overwriting.
To avoid the need to save another register to hold MAS1 during the
workaround code, TID clearing has been moved from tlb_miss_kernel_e6500
until after the SMT section.
Signed-off-by: Scott Wood <scottwood@freescale.com>
There are still a few occurences where it remains, because it helps to
explain something that persists.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Now that we have dropped power3 support we can remove CONFIG_POWER3. The
usage in pgtable_32.c was already dead code as CONFIG_POWER3 was not
selectable on PPC32.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
We now only support cpus that use an SLB, so we don't need an MMU
feature to indicate that.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Old cpus didn't have a Segment Lookaside Buffer (SLB), instead they had
a Segment Table (STAB). Now that we've dropped support for those cpus,
we can remove the STAB support entirely.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
In fb5a515704 "powerpc: Remove platforms/wsp and associated pieces",
we removed the last user of MMU_FTRS_A2. So remove it.
MMU_FTRS_A2 was the last user of MMU_FTR_TYPE_3E, so remove it also.
This leaves some unreachable code in mmu_context_nohash.c, so remove
that also.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Virtualized environments may expose a e6500 dual-threaded core
as two single-threaded e6500 cores. Take advantage of this
and get rid of the tlb lock and the trap-causing tlbsx in
the htw miss handler by guarding with CPU_FTR_SMT, as it's
already being done in the bolted tlb1 miss handler.
As seen in the results below, measurements done with lmbench
random memory access latency test running under Freescale's
Embedded Hypervisor, there is a ~34% improvement.
Memory latencies in nanoseconds - smaller is better
(WARNING - may not be correct, check graphs)
----------------------------------------------------
Host Mhz L1 $ L2 $ Main mem Rand mem
--------- --- ---- ---- -------- --------
smt 1665 1.8020 13.2 83.0 1149.7
nosmt 1665 1.8020 13.2 83.0 758.1
Signed-off-by: Laurentiu Tudor <Laurentiu.Tudor@freescale.com>
Cc: Scott Wood <scottwood@freescale.com>
[scottwood@freescale.com: commit message tweak]
Signed-off-by: Scott Wood <scottwood@freescale.com>
Commit 82d86de25b "TLB lock recursive"
introduced a bug whereby cpu 0 uses the same value for "lock held" as
is used to indicate that the lock is free. This means that cpu 1 can
acquire the lock whenever it wants, regardless of whether cpu 0 has it
locked, which in turn means we can get duplicate TLB entries.
Add one to the CPU value to ensure we do not use zero as a "lock held"
value.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Reported-by: Ed Swarthout <ed.swarthout@freescale.com>
Previously TID was being cleared before the tlbsx, but not after. This
can lead to a multiway hit between a TLB entry with TID=0 (previously
inserted when PID=0) and a TLB entry with TID!=0 that matches PID.
This can theoretically result in undefined behavior, though we probably
get lucky due to the details of the overlap. It also results in the
inability to use multihit detection to detect other conflicting TLB
entries, as well as poorer TLB utilization due to duplicating kernel
TLB entries.
Rather than try to patch up MAS1 after tlbsx, the entire value is
saved/restored as with MAS2.
I observed a slight improvement in TLB miss performance with this patch
applied.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Reported-by: Ed Swarthout <ed.swarthout@freescale.com>
Pull powerpc updates from Ben Herrenschmidt:
"Here is the bulk of the powerpc changes for this merge window. It got
a bit delayed in part because I wasn't paying attention, and in part
because I discovered I had a core PCI change without a PCI maintainer
ack in it. Bjorn eventually agreed it was ok to merge it though we'll
probably improve it later and I didn't want to rebase to add his ack.
There is going to be a bit more next week, essentially fixes that I
still want to sort through and test.
The biggest item this time is the support to build the ppc64 LE kernel
with our new v2 ABI. We previously supported v2 userspace but the
kernel itself was a tougher nut to crack. This is now sorted mostly
thanks to Anton and Rusty.
We also have a fairly big series from Cedric that add support for
64-bit LE zImage boot wrapper. This was made harder by the fact that
traditionally our zImage wrapper was always 32-bit, but our new LE
toolchains don't really support 32-bit anymore (it's somewhat there
but not really "supported") so we didn't want to rely on it. This
meant more churn that just endian fixes.
This brings some more LE bits as well, such as the ability to run in
LE mode without a hypervisor (ie. under OPAL firmware) by doing the
right OPAL call to reinitialize the CPU to take HV interrupts in the
right mode and the usual pile of endian fixes.
There's another series from Gavin adding EEH improvements (one day we
*will* have a release with less than 20 EEH patches, I promise!).
Another highlight is the support for the "Split core" functionality on
P8 by Michael. This allows a P8 core to be split into "sub cores" of
4 threads which allows the subcores to run different guests under KVM
(the HW still doesn't support a partition per thread).
And then the usual misc bits and fixes ..."
[ Further delayed by gmail deciding that BenH is a dirty spammer.
Google knows. ]
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (155 commits)
powerpc/powernv: Add missing include to LPC code
selftests/powerpc: Test the THP bug we fixed in the previous commit
powerpc/mm: Check paca psize is up to date for huge mappings
powerpc/powernv: Pass buffer size to OPAL validate flash call
powerpc/pseries: hcall functions are exported to modules, need _GLOBAL_TOC()
powerpc: Exported functions __clear_user and copy_page use r2 so need _GLOBAL_TOC()
powerpc/powernv: Set memory_block_size_bytes to 256MB
powerpc: Allow ppc_md platform hook to override memory_block_size_bytes
powerpc/powernv: Fix endian issues in memory error handling code
powerpc/eeh: Skip eeh sysfs when eeh is disabled
powerpc: 64bit sendfile is capped at 2GB
powerpc/powernv: Provide debugfs access to the LPC bus via OPAL
powerpc/serial: Use saner flags when creating legacy ports
powerpc: Add cpu family documentation
powerpc/xmon: Fix up xmon format strings
powerpc/powernv: Add calls to support little endian host
powerpc: Document sysfs DSCR interface
powerpc: Fix regression of per-CPU DSCR setting
powerpc: Split __SYSFS_SPRSETUP macro
arch: powerpc/fadump: Cleaning up inconsistent NULL checks
...
We have a bug in our hugepage handling which exhibits as an infinite
loop of hash faults. If the fault is being taken in the kernel it will
typically trigger the softlockup detector, or the RCU stall detector.
The bug is as follows:
1. mmap(0xa0000000, ..., MAP_FIXED | MAP_HUGE_TLB | MAP_ANONYMOUS ..)
2. Slice code converts the slice psize to 16M.
3. The code on lines 539-540 of slice.c in slice_get_unmapped_area()
synchronises the mm->context with the paca->context. So the paca slice
mask is updated to include the 16M slice.
3. Either:
* mmap() fails because there are no huge pages available.
* mmap() succeeds and the mapping is then munmapped.
In both cases the slice psize remains at 16M in both the paca & mm.
4. mmap(0xa0000000, ..., MAP_FIXED | MAP_ANONYMOUS ..)
5. The slice psize is converted back to 64K. Because of the check on line 539
of slice.c we DO NOT update the paca->context. The paca slice mask is now
out of sync with the mm slice mask.
6. User/kernel accesses 0xa0000000.
7. The SLB miss handler slb_allocate_realmode() **uses the paca slice mask**
to create an SLB entry and inserts it in the SLB.
18. With the 16M SLB entry in place the hardware does a hash lookup, no entry
is found so a data access exception is generated.
19. The data access handler calls do_page_fault() -> handle_mm_fault().
10. __handle_mm_fault() creates a THP mapping with do_huge_pmd_anonymous_page().
11. The hardware retries the access, there is still nothing in the hash table
so once again a data access exception is generated.
12. hash_page() calls into __hash_page_thp() and inserts a mapping in the
hash. Although the THP mapping maps 16M the hashing is done using 64K
as the segment page size.
13. hash_page() returns immediately after calling __hash_page_thp(), skipping
over the code at line 1125. Resulting in the mismatch between the
paca->context and mm->context not being detected.
14. The hardware retries the access, the hash it generates using the 16M
SLB entry does NOT match the hash we inserted.
15. We take another data access and go into __hash_page_thp().
16. We see a valid entry in the hpte_slot_array and so we call updatepp()
which succeeds.
17. Goto 14.
We could fix this in two ways. The first would be to remove or modify
the check on line 539 of slice.c.
The second option is to cause the check of paca psize in hash_page() on
line 1125 to also be done for THP pages.
We prefer the latter, because the check & update of the paca psize is
not done until we know it's necessary. It's also done only on the
current cpu, so we don't need to IPI all other cpus.
Without further rearranging the code, the simplest fix is to pull out
the code that checks paca psize and call it in two places. Firstly for
THP/hugetlb, and secondly for other mappings as before.
Thanks to Dave Jones for trinity, which originally found this bug.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: stable@vger.kernel.org [v3.11+]
Currently hugepage migration is available for all archs which support
pmd-level hugepage, but testing is done only for x86_64 and there're
bugs for other archs. So to avoid breaking such archs, this patch
limits the availability strictly to x86_64 until developers of other
archs get interested in enabling this feature.
Simply disabling hugepage migration on non-x86_64 archs is not enough to
fix the reported problem where sys_move_pages() hits the BUG_ON() in
follow_page(FOLL_GET), so let's fix this by checking if hugepage
migration is supported in vma_migratable().
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Tested-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Miller <davem@davemloft.net>
Cc: <stable@vger.kernel.org> [3.12+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- Another round of clean-up of FDT related code in architecture code.
This removes knowledge of internal FDT details from most architectures
except powerpc.
- Conversion of kernel's custom FDT parsing code to use libfdt.
- DT based initialization for generic serial earlycon. The introduction
of generic serial earlycon support went in thru tty tree.
- Improve the platform device naming for DT probed devices to ensure
unique naming and use parent names instead of a global index.
- Fix a race condition in of_update_property.
- Unify the various linker section OF match tables and fix several
function prototype errors.
- Update platform_get_irq_byname to work in deferred probe cases.
- 2 binding doc updates
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Merge tag 'devicetree-for-3.16' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux into next
Pull DeviceTree updates from Rob Herring:
- Another round of clean-up of FDT related code in architecture code.
This removes knowledge of internal FDT details from most
architectures except powerpc.
- Conversion of kernel's custom FDT parsing code to use libfdt.
- DT based initialization for generic serial earlycon. The
introduction of generic serial earlycon support went in through the
tty tree.
- Improve the platform device naming for DT probed devices to ensure
unique naming and use parent names instead of a global index.
- Fix a race condition in of_update_property.
- Unify the various linker section OF match tables and fix several
function prototype errors.
- Update platform_get_irq_byname to work in deferred probe cases.
- 2 binding doc updates
* tag 'devicetree-for-3.16' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux: (58 commits)
of: handle NULL node in next_child iterators
of/irq: provide more wrappers for !CONFIG_OF
devicetree: bindings: Document micrel vendor prefix
dt: bindings: dwc2: fix required value for the phy-names property
of_pci_irq: kill useless variable in of_irq_parse_pci()
of/irq: do irq resolution in platform_get_irq_byname()
of: Add a testcase for of_find_node_by_path()
of: Make of_find_node_by_path() handle /aliases
of: Create unlocked version of for_each_child_of_node()
lib: add glibc style strchrnul() variant
of: Handle memory@0 node on PPC32 only
pci/of: Remove dead code
of: fix race between search and remove in of_update_property()
of: Use NULL for pointers
of: Stop naming platform_device using dcr address
of: Ensure unique names without sacrificing determinism
tty/serial: pl011: add DT based earlycon support
of/fdt: add FDT serial scanning for earlycon
of/fdt: add FDT address translation support
serial: earlycon: add DT support
...
was a pretty active cycle for KVM. Changes include:
- a lot of s390 changes: optimizations, support for migration,
GDB support and more
- ARM changes are pretty small: support for the PSCI 0.2 hypercall
interface on both the guest and the host (the latter acked by Catalin)
- initial POWER8 and little-endian host support
- support for running u-boot on embedded POWER targets
- pretty large changes to MIPS too, completing the userspace interface
and improving the handling of virtualized timer hardware
- for x86, a larger set of changes is scheduled for 3.17. Still,
we have a few emulator bugfixes and support for running nested
fully-virtualized Xen guests (para-virtualized Xen guests have
always worked). And some optimizations too.
The only missing architecture here is ia64. It's not a coincidence
that support for KVM on ia64 is scheduled for removal in 3.17.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm into next
Pull KVM updates from Paolo Bonzini:
"At over 200 commits, covering almost all supported architectures, this
was a pretty active cycle for KVM. Changes include:
- a lot of s390 changes: optimizations, support for migration, GDB
support and more
- ARM changes are pretty small: support for the PSCI 0.2 hypercall
interface on both the guest and the host (the latter acked by
Catalin)
- initial POWER8 and little-endian host support
- support for running u-boot on embedded POWER targets
- pretty large changes to MIPS too, completing the userspace
interface and improving the handling of virtualized timer hardware
- for x86, a larger set of changes is scheduled for 3.17. Still, we
have a few emulator bugfixes and support for running nested
fully-virtualized Xen guests (para-virtualized Xen guests have
always worked). And some optimizations too.
The only missing architecture here is ia64. It's not a coincidence
that support for KVM on ia64 is scheduled for removal in 3.17"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (203 commits)
KVM: add missing cleanup_srcu_struct
KVM: PPC: Book3S PR: Rework SLB switching code
KVM: PPC: Book3S PR: Use SLB entry 0
KVM: PPC: Book3S HV: Fix machine check delivery to guest
KVM: PPC: Book3S HV: Work around POWER8 performance monitor bugs
KVM: PPC: Book3S HV: Make sure we don't miss dirty pages
KVM: PPC: Book3S HV: Fix dirty map for hugepages
KVM: PPC: Book3S HV: Put huge-page HPTEs in rmap chain for base address
KVM: PPC: Book3S HV: Fix check for running inside guest in global_invalidates()
KVM: PPC: Book3S: Move KVM_REG_PPC_WORT to an unused register number
KVM: PPC: Book3S: Add ONE_REG register names that were missed
KVM: PPC: Add CAP to indicate hcall fixes
KVM: PPC: MPIC: Reset IRQ source private members
KVM: PPC: Graciously fail broken LE hypercalls
PPC: ePAPR: Fix hypercall on LE guest
KVM: PPC: BOOK3S: Remove open coded make_dsisr in alignment handler
KVM: PPC: BOOK3S: Always use the saved DAR value
PPC: KVM: Make NX bit available with magic page
KVM: PPC: Disable NX for old magic page using guests
KVM: PPC: BOOK3S: HV: Add mixed page-size support for guest
...
On LPAR guest systems Linux enables the shadow SLB to indicate to the
hypervisor a number of SLB entries that always have to be available.
Today we go through this shadow SLB and disable all ESID's valid bits.
However, pHyp doesn't like this approach very much and honors us with
fancy machine checks.
Fortunately the shadow SLB descriptor also has an entry that indicates
the number of valid entries following. During the lifetime of a guest
we can just swap that value to 0 and don't have to worry about the
SLB restoration magic.
While we're touching the code, let's also make it more readable (get
rid of rldicl), allow it to deal with a dynamic number of bolted
SLB entries and only do shadow SLB swizzling on LPAR systems.
Signed-off-by: Alexander Graf <agraf@suse.de>
The only way Freescale booke chips support mappings larger than 4K
is via TLB1. The only way we support (direct) TLB1 entries is via
hugetlb, which is not what map_kernel_page() does when given a large
page size.
Without this, a kernel with CONFIG_SPARSEMEM_VMEMMAP enabled crashes on
boot with messages such as:
PID hash table entries: 4096 (order: 3, 32768 bytes)
Sorting __ex_table...
BUG: Bad page state in process swapper pfn:00a2f
page:8000040000023a48 count:0 mapcount:0 mapping:0000040000ffce48 index:0x40000ffbe50
page flags: 0x40000ffda40(active|arch_1|private|private_2|head|tail|swapcache|mappedtodisk|reclaim|swapbacked|unevictable|mlocked)
page dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set
bad because of flags:
page flags: 0x311840(active|private|private_2|swapcache|unevictable|mlocked)
Modules linked in:
CPU: 0 PID: 0 Comm: swapper Not tainted 3.15.0-rc1-00003-g7fa250c #299
Call Trace:
[c00000000098ba20] [c000000000008b3c] .show_stack+0x7c/0x1cc (unreliable)
[c00000000098baf0] [c00000000060aa50] .dump_stack+0x88/0xb4
[c00000000098bb70] [c0000000000c0468] .bad_page+0x144/0x1a0
[c00000000098bc10] [c0000000000c0628] .free_pages_prepare+0x164/0x17c
[c00000000098bcc0] [c0000000000c24cc] .free_hot_cold_page+0x48/0x214
[c00000000098bd60] [c00000000086c318] .free_all_bootmem+0x1fc/0x354
[c00000000098be70] [c00000000085da84] .mem_init+0xac/0xdc
[c00000000098bef0] [c0000000008547b0] .start_kernel+0x21c/0x4d4
[c00000000098bf90] [c000000000000448] .start_here_common+0x20/0x58
Signed-off-by: Scott Wood <scottwood@freescale.com>
This request includes a few bug fixes that really shouldn't wait for the next
release.
It fixes KVM on 32bit PowerPC when built as module. It also fixes the PV KVM
acceleration when NX gets honored by the host. Furthermore we fix transactional
memory support and numa support on HV KVM.
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Merge tag 'signed-for-3.15' of git://github.com/agraf/linux-2.6 into kvm-master
Patch queue for 3.15 - 2014-05-12
This request includes a few bug fixes that really shouldn't wait for the next
release.
It fixes KVM on 32bit PowerPC when built as module. It also fixes the PV KVM
acceleration when NX gets honored by the host. Furthermore we fix transactional
memory support and numa support on HV KVM.
This series adds support for building the powerpc 64-bit
LE kernel using the new ABI v2. We already supported
running ABI v2 userspace programs but this adds support
for building the kernel itself using the new ABI.
In case of extending the eaddr in future, use this macro
PGTABLE_EADDR_SIZE to ease the maintenance of the code.
Signed-off-by: Liu Ping Fan <pingfank@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
When we never get around to seeing an HEA ethernet adapter, there's
no point in restricting ourselves to 4k IO page size.
This speeds up IO maps when CONFIG_IBMEBUS is disabled.
[ Updated the test to also lift the restriction on arch 2.07
(Power 8) which cannot have an HEA
-- BenH ]
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
foo
Make of_get_flat_dt_prop arguments compatible with libfdt fdt_getprop
call in preparation to convert FDT code to use libfdt. Make the return
value const and the property length ptr type an int.
Signed-off-by: Rob Herring <robh@kernel.org>
Tested-by: Michal Simek <michal.simek@xilinx.com>
Tested-by: Grant Likely <grant.likely@linaro.org>
Tested-by: Stephen Chivers <schivers@csc.com>
Our PV guest patching code assembles chunks of instructions on the fly when it
encounters more complicated instructions to hijack. These instructions need
to live in a section that we don't mark as non-executable, as otherwise we
fault when jumping there.
Right now we put it into the .bss section where it automatically gets marked
as non-executable. Add a check to the NX setting function to ensure that we
leave these particular pages executable.
Signed-off-by: Alexander Graf <agraf@suse.de>
The if condition check was based on a draft ISA doc. Remove the same.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
The MMU hashtable and SLB branch patching code uses function
pointers for the update sites. This creates a difference between
ABIv1 and ABIv2 because we don't have function descriptors on
ABIv2.
Get rid of the function pointer and just point at the update
sites directly. This works on both ABIs.
Signed-off-by: Anton Blanchard <anton@samba.org>
binutils is smart enough to know that a branch to a function
descriptor is actually a branch to the functions text address.
Alan tells me that binutils has been doing this for 9 years.
Signed-off-by: Anton Blanchard <anton@samba.org>
Since v1:
Edited the comment according to Srivatsa's suggestion.
During the testing, we encounter below WARN followed by Oops:
WARNING: at kernel/sched/core.c:6218
...
NIP [c000000000101660] .build_sched_domains+0x11d0/0x1200
LR [c000000000101358] .build_sched_domains+0xec8/0x1200
PACATMSCRATCH [800000000000f032]
Call Trace:
[c00000001b103850] [c000000000101358] .build_sched_domains+0xec8/0x1200
[c00000001b1039a0] [c00000000010aad4] .partition_sched_domains+0x484/0x510
[c00000001b103aa0] [c00000000016d0a8] .rebuild_sched_domains+0x68/0xa0
[c00000001b103b30] [c00000000005cbf0] .topology_work_fn+0x10/0x30
...
Oops: Kernel access of bad area, sig: 11 [#1]
...
NIP [c00000000045c000] .__bitmap_weight+0x60/0xf0
LR [c00000000010132c] .build_sched_domains+0xe9c/0x1200
PACATMSCRATCH [8000000000029032]
Call Trace:
[c00000001b1037a0] [c000000000288ff4] .kmem_cache_alloc_node_trace+0x184/0x3a0
[c00000001b103850] [c00000000010132c] .build_sched_domains+0xe9c/0x1200
[c00000001b1039a0] [c00000000010aad4] .partition_sched_domains+0x484/0x510
[c00000001b103aa0] [c00000000016d0a8] .rebuild_sched_domains+0x68/0xa0
[c00000001b103b30] [c00000000005cbf0] .topology_work_fn+0x10/0x30
...
This was caused by that 'sd->groups == NULL' after building groups, which
was caused by the empty 'sd->span'.
The cpu's domain contained nothing because the cpu was assigned to a wrong
node, due to the following unfortunate sequence of events:
1. The hypervisor sent a topology update to the guest OS, to notify changes
to the cpu-node mapping. However, the update was actually redundant - i.e.,
the "new" mapping was exactly the same as the old one.
2. Due to this, the 'updated_cpus' mask turned out to be empty after exiting
the 'for-loop' in arch_update_cpu_topology().
3. So we ended up calling stop-machine() with an empty cpumask list, which made
stop-machine internally elect cpumask_first(cpu_online_mask), i.e., CPU0 as
the cpu to run the payload (the update_cpu_topology() function).
4. This causes update_cpu_topology() to be run by CPU0. And since 'updates'
is kzalloc()'ed inside arch_update_cpu_topology(), update_cpu_topology()
finds update->cpu as well as update->new_nid to be 0. In other words, we
end up assigning CPU0 (and eventually its siblings) to node 0, incorrectly.
Along with the following wrong updating, it causes the sched-domain rebuild
code to break and crash the system.
Fix this by skipping the topology update in cases where we find that
the topology has not actually changed in reality (ie., spurious updates).
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <paulus@samba.org>
CC: Nathan Fontenot <nfont@linux.vnet.ibm.com>
CC: Stephen Rothwell <sfr@canb.auug.org.au>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Robert Jennings <rcj@linux.vnet.ibm.com>
CC: Jesse Larrew <jlarrew@linux.vnet.ibm.com>
CC: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
CC: Alistair Popple <alistair@popple.id.au>
Suggested-by: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
We need to handle numa pte via the slow path
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
