Implement the bulk of interrupt return logic in C. The asm return code
must handle a few cases: restoring full GPRs, and emulating stack
store.
The stack store emulation is significantly simplfied, rather than
creating a new return frame and switching to that before performing
the store, it uses the PACA to keep a scratch register around to
perform the store.
The asm return code is moved into 64e for now. The new logic has made
allowance for 64e, but I don't have a full environment that works well
to test it, and even booting in emulated qemu is not great for stress
testing. 64e shouldn't be too far off working with this, given a bit
more testing and auditing of the logic.
This is slightly faster on a POWER9 (page fault speed increases about
1.1%), probably due to reduced mtmsrd.
mpe: Includes fixes from Nick for _TIF_EMULATE_STACK_STORE
handling (including the fast_interrupt_return path), to remove
trace_hardirqs_on(), and fixes the interrupt-return part of the
MSR_VSX restore bug caught by tm-unavailable selftest.
mpe: Incorporate fix from Nick:
The return-to-kernel path has to replay any soft-pending interrupts if
it is returning to a context that had interrupts soft-enabled. It has
to do this carefully and avoid plain enabling interrupts if this is an
irq context, which can cause multiple nesting of interrupts on the
stack, and other unexpected issues.
The code which avoided this case got the soft-mask state wrong, and
marked interrupts as enabled before going around again to retry. This
seems to be mostly harmless except when PREEMPT=y, this calls
preempt_schedule_irq with irqs apparently enabled and runs into a BUG
in kernel/sched/core.c
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michal Suchanek <msuchanek@suse.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200225173541.1549955-29-npiggin@gmail.com
System call entry and particularly exit code is beyond the limit of
what is reasonable to implement in asm.
This conversion moves all conditional branches out of the asm code,
except for the case that all GPRs should be restored at exit.
Null syscall test is about 5% faster after this patch, because the
exit work is handled under local_irq_disable, and the hard mask and
pending interrupt replay is handled after that, which avoids games
with MSR.
mpe: Includes subsequent fixes from Nick:
This fixes 4 issues caught by TM selftests. First was a tm-syscall bug
that hit due to tabort_syscall being called after interrupts were
reconciled (in a subsequent patch), which led to interrupts being
enabled before tabort_syscall was called. Rather than going through an
un-reconciling interrupts for the return, I just go back to putting
the test early in asm, the C-ification of that wasn't a big win
anyway.
Second is the syscall return _TIF_USER_WORK_MASK check would go into
an infinite loop if _TIF_RESTORE_TM became set. The asm code uses
_TIF_USER_WORK_MASK to brach to slowpath which includes
restore_tm_state.
Third is system call return was not calling restore_tm_state, I missed
this completely (alhtough it's in the return from interrupt C
conversion because when the asm syscall code encountered problems it
would branch to the interrupt return code.
Fourth is MSR_VEC missing from restore_math, which was caught by
tm-unavailable selftest taking an unexpected facility unavailable
interrupt when testing VSX unavailble exception with MSR.FP=1
MSR.VEC=1. Fourth case also has a fixup in a subsequent patch.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michal Suchanek <msuchanek@suse.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200225173541.1549955-26-npiggin@gmail.com
H_PAGE_THP_HUGE is used to differentiate between a THP hugepage and
hugetlb hugepage entries. The difference is WRT how we handle hash
fault on these address. THP address enables MPSS in segments. We want
to manage devmap hugepage entries similar to THP pt entries. Hence use
H_PAGE_THP_HUGE for devmap huge PTE entries.
With current code while handling hash PTE fault, we do set is_thp =
true when finding devmap PTE huge PTE entries.
Current code also does the below sequence we setting up huge devmap
entries.
entry = pmd_mkhuge(pfn_t_pmd(pfn, prot));
if (pfn_t_devmap(pfn))
entry = pmd_mkdevmap(entry);
In that case we would find both H_PAGE_THP_HUGE and PAGE_DEVMAP set
for huge devmap PTE entries. This results in false positive error like
below.
kernel BUG at /home/kvaneesh/src/linux/mm/memory.c:4321!
Oops: Exception in kernel mode, sig: 5 [#1]
LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
Modules linked in:
CPU: 56 PID: 67996 Comm: t_mmap_dio Not tainted 5.6.0-rc4-59640-g371c804dedbc #128
....
NIP [c00000000044c9e4] __follow_pte_pmd+0x264/0x900
LR [c0000000005d45f8] dax_writeback_one+0x1a8/0x740
Call Trace:
str_spec.74809+0x22ffb4/0x2d116c (unreliable)
dax_writeback_one+0x1a8/0x740
dax_writeback_mapping_range+0x26c/0x700
ext4_dax_writepages+0x150/0x5a0
do_writepages+0x68/0x180
__filemap_fdatawrite_range+0x138/0x180
file_write_and_wait_range+0xa4/0x110
ext4_sync_file+0x370/0x6e0
vfs_fsync_range+0x70/0xf0
sys_msync+0x220/0x2e0
system_call+0x5c/0x68
This is because our pmd_trans_huge check doesn't exclude _PAGE_DEVMAP.
To make this all consistent, update pmd_mkdevmap to set
H_PAGE_THP_HUGE and pmd_trans_huge check now excludes _PAGE_DEVMAP
correctly.
Fixes: ebd3119793 ("powerpc/mm: Add devmap support for ppc64")
Cc: stable@vger.kernel.org # v4.13+
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/20200313094842.351830-1-aneesh.kumar@linux.ibm.com
Reorder Linux PTE bits to (almost) match Hash PTE bits.
RW Kernel : PP = 00
RO Kernel : PP = 00
RW User : PP = 01
RO User : PP = 11
So naturally, we should have
_PAGE_USER = 0x001
_PAGE_RW = 0x002
Today 0x001 and 0x002 and _PAGE_PRESENT and _PAGE_HASHPTE which
both are software only bits.
Switch _PAGE_USER and _PAGE_PRESET
Switch _PAGE_RW and _PAGE_HASHPTE
This allows to remove a few insns.
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/c4d6c18a7f8d9d3b899bc492f55fbc40ef38896a.1583861325.git.christophe.leroy@c-s.fr
On PPC32, pte_offset_map() does a kmap_atomic() in order to support
page tables allocated in high memory, just like ARM and x86/32.
But since at least 2008 and commit 8054a3428f ("powerpc: Remove dead
CONFIG_HIGHPTE"), page tables are never allocated in high memory.
When the page is in low mem, kmap_atomic() just returns the page
address but still disable preemption and pagefault. And it is
not an inlined function, so we suffer function call for no reason.
Make pte_offset_map() the same as pte_offset_kernel() and make
pte_unmap() void, in the same way as PPC64 which doesn't have HIGHMEM.
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/03c97f0f6b3790d164822563be80f2fd4713a955.1581932480.git.christophe.leroy@c-s.fr
- Implement user_access_begin() and friends for our platforms that support
controlling kernel access to userspace.
- Enable CONFIG_VMAP_STACK on 32-bit Book3S and 8xx.
- Some tweaks to our pseries IOMMU code to allow SVMs ("secure" virtual
machines) to use the IOMMU.
- Add support for CLOCK_{REALTIME/MONOTONIC}_COARSE to the 32-bit VDSO, and
some other improvements.
- A series to use the PCI hotplug framework to control opencapi card's so that
they can be reset and re-read after flashing a new FPGA image.
As well as other minor fixes and improvements as usual.
Thanks to:
Alastair D'Silva, Alexandre Ghiti, Alexey Kardashevskiy, Andrew Donnellan,
Aneesh Kumar K.V, Anju T Sudhakar, Bai Yingjie, Chen Zhou, Christophe Leroy,
Frederic Barrat, Greg Kurz, Jason A. Donenfeld, Joel Stanley, Jordan Niethe,
Julia Lawall, Krzysztof Kozlowski, Laurent Dufour, Laurentiu Tudor, Linus
Walleij, Michael Bringmann, Nathan Chancellor, Nicholas Piggin, Nick
Desaulniers, Oliver O'Halloran, Peter Ujfalusi, Pingfan Liu, Ram Pai, Randy
Dunlap, Russell Currey, Sam Bobroff, Sebastian Andrzej Siewior, Shawn
Anastasio, Stephen Rothwell, Steve Best, Sukadev Bhattiprolu, Thiago Jung
Bauermann, Tyrel Datwyler, Vaibhav Jain.
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Merge tag 'powerpc-5.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman:
"A pretty small batch for us, and apologies for it being a bit late, I
wanted to sneak Christophe's user_access_begin() series in.
Summary:
- Implement user_access_begin() and friends for our platforms that
support controlling kernel access to userspace.
- Enable CONFIG_VMAP_STACK on 32-bit Book3S and 8xx.
- Some tweaks to our pseries IOMMU code to allow SVMs ("secure"
virtual machines) to use the IOMMU.
- Add support for CLOCK_{REALTIME/MONOTONIC}_COARSE to the 32-bit
VDSO, and some other improvements.
- A series to use the PCI hotplug framework to control opencapi
card's so that they can be reset and re-read after flashing a new
FPGA image.
As well as other minor fixes and improvements as usual.
Thanks to: Alastair D'Silva, Alexandre Ghiti, Alexey Kardashevskiy,
Andrew Donnellan, Aneesh Kumar K.V, Anju T Sudhakar, Bai Yingjie, Chen
Zhou, Christophe Leroy, Frederic Barrat, Greg Kurz, Jason A.
Donenfeld, Joel Stanley, Jordan Niethe, Julia Lawall, Krzysztof
Kozlowski, Laurent Dufour, Laurentiu Tudor, Linus Walleij, Michael
Bringmann, Nathan Chancellor, Nicholas Piggin, Nick Desaulniers,
Oliver O'Halloran, Peter Ujfalusi, Pingfan Liu, Ram Pai, Randy Dunlap,
Russell Currey, Sam Bobroff, Sebastian Andrzej Siewior, Shawn
Anastasio, Stephen Rothwell, Steve Best, Sukadev Bhattiprolu, Thiago
Jung Bauermann, Tyrel Datwyler, Vaibhav Jain"
* tag 'powerpc-5.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (131 commits)
powerpc: configs: Cleanup old Kconfig options
powerpc/configs/skiroot: Enable some more hardening options
powerpc/configs/skiroot: Disable xmon default & enable reboot on panic
powerpc/configs/skiroot: Enable security features
powerpc/configs/skiroot: Update for symbol movement only
powerpc/configs/skiroot: Drop default n CONFIG_CRYPTO_ECHAINIV
powerpc/configs/skiroot: Drop HID_LOGITECH
powerpc/configs: Drop NET_VENDOR_HP which moved to staging
powerpc/configs: NET_CADENCE became NET_VENDOR_CADENCE
powerpc/configs: Drop CONFIG_QLGE which moved to staging
powerpc: Do not consider weak unresolved symbol relocations as bad
powerpc/32s: Fix kasan_early_hash_table() for CONFIG_VMAP_STACK
powerpc: indent to improve Kconfig readability
powerpc: Provide initial documentation for PAPR hcalls
powerpc: Implement user_access_save() and user_access_restore()
powerpc: Implement user_access_begin and friends
powerpc/32s: Prepare prevent_user_access() for user_access_end()
powerpc/32s: Drop NULL addr verification
powerpc/kuap: Fix set direction in allow/prevent_user_access()
powerpc/32s: Fix bad_kuap_fault()
...
Patch series "Fixup page directory freeing", v4.
This is a repost of patch series from Peter with the arch specific changes
except ppc64 dropped. ppc64 changes are added here because we are redoing
the patch series on top of ppc64 changes. This makes it easy to backport
these changes. Only the first 2 patches need to be backported to stable.
The thing is, on anything SMP, freeing page directories should observe the
exact same order as normal page freeing:
1) unhook page/directory
2) TLB invalidate
3) free page/directory
Without this, any concurrent page-table walk could end up with a
Use-after-Free. This is esp. trivial for anything that has software
page-table walkers (HAVE_FAST_GUP / software TLB fill) or the hardware
caches partial page-walks (ie. caches page directories).
Even on UP this might give issues since mmu_gather is preemptible these
days. An interrupt or preempted task accessing user pages might stumble
into the free page if the hardware caches page directories.
This patch series fixes ppc64 and add generic MMU_GATHER changes to
support the conversion of other architectures. I haven't added patches
w.r.t other architecture because they are yet to be acked.
This patch (of 9):
A followup patch is going to make sure we correctly invalidate page walk
cache before we free page table pages. In order to keep things simple
enable RCU_TABLE_FREE even for !SMP so that we don't have to fixup the
!SMP case differently in the followup patch
!SMP case is right now broken for radix translation w.r.t page walk
cache flush. We can get interrupted in between page table free and
that would imply we have page walk cache entries pointing to tables
which got freed already. Michael said "both our platforms that run on
Power9 force SMP on in Kconfig, so the !SMP case is unlikely to be a
problem for anyone in practice, unless they've hacked their kernel to
build it !SMP."
Link: http://lkml.kernel.org/r/20200116064531.483522-2-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
walk_page_range() is going to be allowed to walk page tables other than
those of user space. For this it needs to know when it has reached a
'leaf' entry in the page tables. This information is provided by the
p?d_leaf() functions/macros.
For powerpc p?d_is_leaf() functions already exist. Export them using the
new p?d_leaf() name.
Link: http://lkml.kernel.org/r/20191218162402.45610-7-steven.price@arm.com
Signed-off-by: Steven Price <steven.price@arm.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Hogan <jhogan@kernel.org>
Cc: James Morse <james.morse@arm.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: "Liang, Kan" <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Cc: Zong Li <zong.li@sifive.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Implement user_access_save() and user_access_restore()
On 8xx and radix:
- On save, get the value of the associated special register then
prevent user access.
- On restore, set back the saved value to the associated special
register.
On book3s/32:
- On save, get the value stored in current->thread.kuap and prevent
user access.
- On restore, regenerate address range from the stored value and
reopen read/write access for that range.
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/54f2f74938006b33c55a416674807b42ef222068.1579866752.git.christophe.leroy@c-s.fr
In preparation of implementing user_access_begin and friends
on powerpc, the book3s/32 version of prevent_user_access() need
to be prepared for user_access_end().
user_access_end() doesn't provide the address and size which
were passed to user_access_begin(), required by prevent_user_access()
to know which segment to modify.
The list of segments which where unprotected by allow_user_access()
are available in current->kuap. But we don't want prevent_user_access()
to read this all the time, especially everytime it is 0 (for instance
because the access was not a write access).
Implement a special direction named KUAP_CURRENT. In this case only,
the addr and end are retrieved from current->kuap.
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/55bcc1f25d8200892a31f67a0b024ff3b816c3cc.1579866752.git.christophe.leroy@c-s.fr
NULL addr is a user address. Don't waste time checking it. If
someone tries to access it, it will SIGFAULT the same way as for
address 1, so no need to make it special.
The special case is when not doing a write, in that case we want
to drop the entire function. This is now handled by 'dir' param
and not by the nulity of 'to' anymore.
Also make beginning of prevent_user_access() similar
to beginning of allow_user_access(), and tell the compiler
that writing in kernel space or with a 0 length is unlikely
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/85e971223dfe6ace734637db1841678939a76155.1579866752.git.christophe.leroy@c-s.fr
At the moment, bad_kuap_fault() reports a fault only if a bad access
to userspace occurred while access to userspace was not granted.
But if a fault occurs for a write outside the allowed userspace
segment(s) that have been unlocked, bad_kuap_fault() fails to
detect it and the kernel loops forever in do_page_fault().
Fix it by checking that the accessed address is within the allowed
range.
Fixes: a68c31fc01 ("powerpc/32s: Implement 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/f48244e9485ada0a304ed33ccbb8da271180c80d.1579866752.git.christophe.leroy@c-s.fr
Add support of KASAN_VMALLOC on PPC32.
To allow this, the early shadow covering the VMALLOC space
need to be removed once high_memory var is set and before
freeing memblock.
And the VMALLOC area need to be aligned such that boundaries
are covered by a full shadow page.
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/031dec5487bde9b2181c8b3c9800e1879cf98c1a.1579024426.git.christophe.leroy@c-s.fr
Commit 0034d395f8 ("powerpc/mm/hash64: Map all the kernel regions in
the same 0xc range") has a bug in the definition of MIN_USER_CONTEXT.
The result is that the context id used for the vmemmap and the lowest
context id handed out to userspace are the same. The context id is
essentially the process identifier as far as the first stage of the
MMU translation is concerned.
This can result in multiple SLB entries with the same VSID (Virtual
Segment ID), accessible to the kernel and some random userspace
process that happens to get the overlapping id, which is not expected
eg:
07 c00c000008000000 40066bdea7000500 1T ESID= c00c00 VSID= 66bdea7 LLP:100
12 0002000008000000 40066bdea7000d80 1T ESID= 200 VSID= 66bdea7 LLP:100
Even though the user process and the kernel use the same VSID, the
permissions in the hash page table prevent the user process from
reading or writing to any kernel mappings.
It can also lead to SLB entries with different base page size
encodings (LLP), eg:
05 c00c000008000000 00006bde0053b500 256M ESID=c00c00000 VSID= 6bde0053b LLP:100
09 0000000008000000 00006bde0053bc80 256M ESID= 0 VSID= 6bde0053b LLP: 0
Such SLB entries can result in machine checks, eg. as seen on a G5:
Oops: Machine check, sig: 7 [#1]
BE PAGE SIZE=64K MU-Hash SMP NR_CPUS=4 NUMA Power Mac
NIP: c00000000026f248 LR: c000000000295e58 CTR: 0000000000000000
REGS: c0000000erfd3d70 TRAP: 0200 Tainted: G M (5.5.0-rcl-gcc-8.2.0-00010-g228b667d8ea1)
MSR: 9000000000109032 <SF,HV,EE,ME,IR,DR,RI> CR: 24282048 XER: 00000000
DAR: c00c000000612c80 DSISR: 00000400 IRQMASK: 0
...
NIP [c00000000026f248] .kmem_cache_free+0x58/0x140
LR [c088000008295e58] .putname 8x88/0xa
Call Trace:
.putname+0xB8/0xa
.filename_lookup.part.76+0xbe/0x160
.do_faccessat+0xe0/0x380
system_call+0x5c/ex68
This happens with 256MB segments and 64K pages, as the duplicate VSID
is hit with the first vmemmap segment and the first user segment, and
older 32-bit userspace maps things in the first user segment.
On other CPUs a machine check is not seen. Instead the userspace
process can get stuck continuously faulting, with the fault never
properly serviced, due to the kernel not understanding that there is
already a HPTE for the address but with inaccessible permissions.
On machines with 1T segments we've not seen the bug hit other than by
deliberately exercising it. That seems to be just a matter of luck
though, due to the typical layout of the user virtual address space
and the ranges of vmemmap that are typically populated.
To fix it we add 2 to MIN_USER_CONTEXT. This ensures the lowest
context given to userspace doesn't overlap with the VMEMMAP context,
or with the context for INVALID_REGION_ID.
Fixes: 0034d395f8 ("powerpc/mm/hash64: Map all the kernel regions in the same 0xc range")
Cc: stable@vger.kernel.org # v5.2+
Reported-by: Christian Marillat <marillat@debian.org>
Reported-by: Romain Dolbeau <romain@dolbeau.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
[mpe: Account for INVALID_REGION_ID, mostly rewrite change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200123102547.11623-1-mpe@ellerman.id.au
Merge updates from Andrew Morton:
"Incoming:
- a small number of updates to scripts/, ocfs2 and fs/buffer.c
- most of MM
I still have quite a lot of material (mostly not MM) staged after
linux-next due to -next dependencies. I'll send those across next week
as the preprequisites get merged up"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (135 commits)
mm/page_io.c: annotate refault stalls from swap_readpage
mm/Kconfig: fix trivial help text punctuation
mm/Kconfig: fix indentation
mm/memory_hotplug.c: remove __online_page_set_limits()
mm: fix typos in comments when calling __SetPageUptodate()
mm: fix struct member name in function comments
mm/shmem.c: cast the type of unmap_start to u64
mm: shmem: use proper gfp flags for shmem_writepage()
mm/shmem.c: make array 'values' static const, makes object smaller
userfaultfd: require CAP_SYS_PTRACE for UFFD_FEATURE_EVENT_FORK
fs/userfaultfd.c: wp: clear VM_UFFD_MISSING or VM_UFFD_WP during userfaultfd_register()
userfaultfd: wrap the common dst_vma check into an inlined function
userfaultfd: remove unnecessary WARN_ON() in __mcopy_atomic_hugetlb()
userfaultfd: use vma_pagesize for all huge page size calculation
mm/madvise.c: use PAGE_ALIGN[ED] for range checking
mm/madvise.c: replace with page_size() in madvise_inject_error()
mm/mmap.c: make vma_merge() comment more easy to understand
mm/hwpoison-inject: use DEFINE_DEBUGFS_ATTRIBUTE to define debugfs fops
autonuma: reduce cache footprint when scanning page tables
autonuma: fix watermark checking in migrate_balanced_pgdat()
...
Patch series "hugetlbfs: convert macros to static inline, fix sparse
warning".
The definition for huge_pte_offset() in <linux/hugetlb.h> causes a
sparse warning in the !CONFIG_HUGETLB_PAGE. Fix this as well as
converting all macros in this block of definitions to static inlines for
better type checking.
When making the above changes, build errors were found in powerpc due to
duplicate definitions. A separate powerpc specific patch is included as
a requisite to remove the definitions and get them from
<linux/hugetlb.h>.
This patch (of 2):
This removes the power specific stubs created by commit aad71e3928
("powerpc/mm: Fix build break with RADIX=y & HUGETLBFS=n") used when
!CONFIG_HUGETLB_PAGE. Instead, it addresses the build break by getting
the definitions from <linux/hugetlb.h>. This allows the macros in
<linux/hugetlb.h> to be replaced with static inlines.
Link: http://lkml.kernel.org/r/20191112194558.139389-2-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: Ben Dooks <ben.dooks@codethink.co.uk>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With commit 22a61c3c4f ("asm-generic/tlb: Track freeing of
page-table directories in struct mmu_gather") we now track whether we
freed page table in mmu_gather. Use that to decide whether to flush
Page Walk Cache.
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/20191024075801.22434-2-aneesh.kumar@linux.ibm.com
Make sure starting addr is aligned to segment boundary so that when
incrementing the segment, the starting address of the new segment is
below the end address. Otherwise the last segment might get missed.
Fixes: a68c31fc01 ("powerpc/32s: Implement Kernel Userspace Access Protection")
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/067a1b09f15f421d40797c2d04c22d4049a1cee8.1571071875.git.christophe.leroy@c-s.fr
After merging the powerpc tree, today's linux-next build (powerpc64
allnoconfig) failed like this:
arch/powerpc/mm/book3s64/pgtable.c:216:3:
error: implicit declaration of function 'radix__flush_all_lpid_guest'
radix__flush_all_lpid_guest() is only declared for
CONFIG_PPC_RADIX_MMU which is not set for this build.
Fix it by adding an empty version for the RADIX_MMU=n case, which
should never be called.
Fixes: 99161de3a2 ("powerpc/64s/radix: tidy up TLB flushing code")
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
[mpe: Munge change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190930101342.36c1afa0@canb.auug.org.au
- Complete the reworks to interoperate with powerpc dynamic huge page sizes
- Fix a crash due to missed accounting for the powerpc 'struct
page'-memmap mapping granularity.
- Fix badblock initialization for volatile (DRAM emulated) pmem ranges.
- Stop triggering request_key() notifications to userspace when
NVDIMM-security is disabled / not present.
- Miscellaneous small fixups.
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Merge tag 'libnvdimm-fixes-5.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
More libnvdimm updates from Dan Williams:
- Complete the reworks to interoperate with powerpc dynamic huge page
sizes
- Fix a crash due to missed accounting for the powerpc 'struct
page'-memmap mapping granularity
- Fix badblock initialization for volatile (DRAM emulated) pmem ranges
- Stop triggering request_key() notifications to userspace when
NVDIMM-security is disabled / not present
- Miscellaneous small fixups
* tag 'libnvdimm-fixes-5.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
libnvdimm/region: Enable MAP_SYNC for volatile regions
libnvdimm: prevent nvdimm from requesting key when security is disabled
libnvdimm/region: Initialize bad block for volatile namespaces
libnvdimm/nfit_test: Fix acpi_handle redefinition
libnvdimm/altmap: Track namespace boundaries in altmap
libnvdimm: Fix endian conversion issues
libnvdimm/dax: Pick the right alignment default when creating dax devices
powerpc/book3s64: Export has_transparent_hugepage() related functions.
In later patch, we want to use hash_transparent_hugepage() in a kernel module.
Export two related functions.
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Link: https://lore.kernel.org/r/20190924042440.27946-1-aneesh.kumar@linux.ibm.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Introduce two options to control the use of the tlbie instruction. A
boot time option which completely disables the kernel using the
instruction, this is currently incompatible with HASH MMU, KVM, and
coherent accelerators.
And a debugfs option can be switched at runtime and avoids using tlbie
for invalidating CPU TLBs for normal process and kernel address
mappings. Coherent accelerators are still managed with tlbie, as will
KVM partition scope translations.
Cross-CPU TLB flushing is implemented with IPIs and tlbiel. This is a
basic implementation which does not attempt to make any optimisation
beyond the tlbie implementation.
This is useful for performance testing among other things. For example
in certain situations on large systems, using IPIs may be faster than
tlbie as they can be directed rather than broadcast. Later we may also
take advantage of the IPIs to do more interesting things such as trim
the mm cpumask more aggressively.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190902152931.17840-7-npiggin@gmail.com
There should be no functional changes.
- Use calls to existing radix_tlb.c functions in flush_partition.
- Rename radix__flush_tlb_lpid to radix__flush_all_lpid and similar,
because they flush everything, matching flush_all_mm rather than
flush_tlb_mm for the lpid.
- Remove some unused radix_tlb.c flush primitives.
Signed-off: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190902152931.17840-3-npiggin@gmail.com
This callback is only required because the partition table init comes
before process table allocation on powernv (aka bare metal aka native).
Change the order to allocate the process table first, and remove the
callback.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190902152931.17840-2-npiggin@gmail.com
This switches to using common code for the DMA allocations, including
potential use of the CMA allocator if configured.
Switching to the generic code enables DMA allocations from atomic
context, which is required by the DMA API documentation, and also
adds various other minor features drivers start relying upon. It
also makes sure we have on tested code base for all architectures
that require uncached pte bits for coherent DMA allocations.
Another advantage is that consistent memory allocations now share
the general vmalloc pool instead of needing an explicit careout
from it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Christophe Leroy <christophe.leroy@c-s.fr> # tested on 8xx
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190814132230.31874-2-hch@lst.de
PPC32 and PPC64 are doing the same once SLAB is available.
Create a do_ioremap() function that calls get_vm_area and
do the mapping.
For PPC64, we add the 4K PFN hack sanity check to __ioremap_caller()
in order to avoid using __ioremap_at(). Other checks in __ioremap_at()
are irrelevant for __ioremap_caller().
On PPC64, VM area is allocated in the range [ioremap_bot ; IOREMAP_END]
On PPC32, VM area is allocated in the range [VMALLOC_START ; VMALLOC_END]
Lets define IOREMAP_START is ioremap_bot for PPC64, and alias
IOREMAP_START/END to VMALLOC_START/END on PPC32
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/42e7e36ad32e0fdf76692426cc642799c9f689b8.1566309263.git.christophe.leroy@c-s.fr
book3s64's ioremap_range() is almost same as fallback ioremap_range(),
except that it calls radix__ioremap_range() when radix is enabled.
radix__ioremap_range() is also very similar to the other ones, expect
that it calls ioremap_page_range when slab is available.
PPC32 __ioremap_caller() have a loop doing the same thing as
ioremap_range() so use it on PPC32 as well.
Lets keep only one version of ioremap_range() which calls
ioremap_page_range() on all platforms when slab is available.
At the same time, drop the nid parameter which is not used.
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/4b1dca7096b01823b101be7338983578641547f1.1566309263.git.christophe.leroy@c-s.fr
Drop multiple definitions of ioremap_bot and make one common to
all subarches.
Only CONFIG_PPC_BOOK3E_64 had a global static init value for
ioremap_bot. Now ioremap_bot is set in early_init_mmu_global().
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/920eebfd9f36f14c79d1755847f5bf7c83703bdd.1566309262.git.christophe.leroy@c-s.fr
pfn_pte is never given a pte above the addressable physical memory
limit, so the masking is redundant. In case of a software bug, it
is not obviously better to silently truncate the pfn than to corrupt
the pte (either one will result in memory corruption or crashes),
so there is no reason to add this to the fast path.
Add VM_BUG_ON to catch cases where the pfn is invalid. These would
catch the create_section_mapping bug fixed by a previous commit.
[16885.256466] ------------[ cut here ]------------
[16885.256492] kernel BUG at arch/powerpc/include/asm/book3s/64/pgtable.h:612!
cpu 0x0: Vector: 700 (Program Check) at [c0000000ee0a36d0]
pc: c000000000080738: __map_kernel_page+0x248/0x6f0
lr: c000000000080ac0: __map_kernel_page+0x5d0/0x6f0
sp: c0000000ee0a3960
msr: 9000000000029033
current = 0xc0000000ec63b400
paca = 0xc0000000017f0000 irqmask: 0x03 irq_happened: 0x01
pid = 85, comm = sh
kernel BUG at arch/powerpc/include/asm/book3s/64/pgtable.h:612!
Linux version 5.3.0-rc1-00001-g0fe93e5f3394
enter ? for help
[c0000000ee0a3a00] c000000000d37378 create_physical_mapping+0x260/0x360
[c0000000ee0a3b10] c000000000d370bc create_section_mapping+0x1c/0x3c
[c0000000ee0a3b30] c000000000071f54 arch_add_memory+0x74/0x130
Signed-off-by: Nicholas Piggin <npiggin@gmail.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/20190724084638.24982-5-npiggin@gmail.com
Only BOOK3S and FSL_BOOK3E have a usefull update_mmu_cache().
For the others, just define it static inline.
In the meantime, simplify the FSL_BOOK3E related ifdef as
book3e_hugetlb_preload() only exists when CONFIG_PPC_FSL_BOOK3E
is selected.
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/668aba4db6b9af6d8a151174e11a4289f1a6bbcd.1565933217.git.christophe.leroy@c-s.fr
ARCH_HAS_ZONE_DEVICE is somewhat meaningless in itself, and combined
with the long-out-of-date comment can lead to the impression than an
architecture may just enable it (since __add_pages() now "comprehends
device memory" for itself) and expect things to work.
In practice, however, ZONE_DEVICE users have little chance of
functioning correctly without __HAVE_ARCH_PTE_DEVMAP, so let's clean
that up the same way as ARCH_HAS_PTE_SPECIAL and make it the proper
dependency so the real situation is clearer.
Link: http://lkml.kernel.org/r/87554aa78478a02a63f2c4cf60a847279ae3eb3b.1558547956.git.robin.murphy@arm.com
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Acked-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Notable changes:
- Removal of the NPU DMA code, used by the out-of-tree Nvidia driver, as well
as some other functions only used by drivers that haven't (yet?) made it
upstream.
- A fix for a bug in our handling of hardware watchpoints (eg. perf record -e
mem: ...) which could lead to register corruption and kernel crashes.
- Enable HAVE_ARCH_HUGE_VMAP, which allows us to use large pages for vmalloc
when using the Radix MMU.
- A large but incremental rewrite of our exception handling code to use gas
macros rather than multiple levels of nested CPP macros.
And the usual small fixes, cleanups and improvements.
Thanks to:
Alastair D'Silva, Alexey Kardashevskiy, Andreas Schwab, Aneesh Kumar K.V, Anju
T Sudhakar, Anton Blanchard, Arnd Bergmann, Athira Rajeev, Cédric Le Goater,
Christian Lamparter, Christophe Leroy, Christophe Lombard, Christoph Hellwig,
Daniel Axtens, Denis Efremov, Enrico Weigelt, Frederic Barrat, Gautham R.
Shenoy, Geert Uytterhoeven, Geliang Tang, Gen Zhang, Greg Kroah-Hartman, Greg
Kurz, Gustavo Romero, Krzysztof Kozlowski, Madhavan Srinivasan, Masahiro
Yamada, Mathieu Malaterre, Michael Neuling, Nathan Lynch, Naveen N. Rao,
Nicholas Piggin, Nishad Kamdar, Oliver O'Halloran, Qian Cai, Ravi Bangoria,
Sachin Sant, Sam Bobroff, Satheesh Rajendran, Segher Boessenkool, Shaokun
Zhang, Shawn Anastasio, Stewart Smith, Suraj Jitindar Singh, Thiago Jung
Bauermann, YueHaibing.
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Merge tag 'powerpc-5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman:
"Notable changes:
- Removal of the NPU DMA code, used by the out-of-tree Nvidia driver,
as well as some other functions only used by drivers that haven't
(yet?) made it upstream.
- A fix for a bug in our handling of hardware watchpoints (eg. perf
record -e mem: ...) which could lead to register corruption and
kernel crashes.
- Enable HAVE_ARCH_HUGE_VMAP, which allows us to use large pages for
vmalloc when using the Radix MMU.
- A large but incremental rewrite of our exception handling code to
use gas macros rather than multiple levels of nested CPP macros.
And the usual small fixes, cleanups and improvements.
Thanks to: Alastair D'Silva, Alexey Kardashevskiy, Andreas Schwab,
Aneesh Kumar K.V, Anju T Sudhakar, Anton Blanchard, Arnd Bergmann,
Athira Rajeev, Cédric Le Goater, Christian Lamparter, Christophe
Leroy, Christophe Lombard, Christoph Hellwig, Daniel Axtens, Denis
Efremov, Enrico Weigelt, Frederic Barrat, Gautham R. Shenoy, Geert
Uytterhoeven, Geliang Tang, Gen Zhang, Greg Kroah-Hartman, Greg Kurz,
Gustavo Romero, Krzysztof Kozlowski, Madhavan Srinivasan, Masahiro
Yamada, Mathieu Malaterre, Michael Neuling, Nathan Lynch, Naveen N.
Rao, Nicholas Piggin, Nishad Kamdar, Oliver O'Halloran, Qian Cai, Ravi
Bangoria, Sachin Sant, Sam Bobroff, Satheesh Rajendran, Segher
Boessenkool, Shaokun Zhang, Shawn Anastasio, Stewart Smith, Suraj
Jitindar Singh, Thiago Jung Bauermann, YueHaibing"
* tag 'powerpc-5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (163 commits)
powerpc/powernv/idle: Fix restore of SPRN_LDBAR for POWER9 stop state.
powerpc/eeh: Handle hugepages in ioremap space
ocxl: Update for AFU descriptor template version 1.1
powerpc/boot: pass CONFIG options in a simpler and more robust way
powerpc/boot: add {get, put}_unaligned_be32 to xz_config.h
powerpc/irq: Don't WARN continuously in arch_local_irq_restore()
powerpc/module64: Use symbolic instructions names.
powerpc/module32: Use symbolic instructions names.
powerpc: Move PPC_HA() PPC_HI() and PPC_LO() to ppc-opcode.h
powerpc/module64: Fix comment in R_PPC64_ENTRY handling
powerpc/boot: Add lzo support for uImage
powerpc/boot: Add lzma support for uImage
powerpc/boot: don't force gzipped uImage
powerpc/8xx: Add microcode patch to move SMC parameter RAM.
powerpc/8xx: Use IO accessors in microcode programming.
powerpc/8xx: replace #ifdefs by IS_ENABLED() in microcode.c
powerpc/8xx: refactor programming of microcode CPM params.
powerpc/8xx: refactor printing of microcode patch name.
powerpc/8xx: Refactor microcode write
powerpc/8xx: refactor writing of CPM microcode arrays
...
Even when we have HugeTLB and THP disabled, kernel linear map can still be
mapped with hugepages. This is only an issue with radix translation because hash
MMU doesn't map kernel linear range in linux page table and other kernel
map areas are not mapped using hugepage.
Add config independent helpers and put WARN_ON() when we don't expect things
to be mapped via hugepages.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Since commit 0034d395f8 ("powerpc/mm/hash64: Map all the kernel
regions in the same 0xc range") __kernel_virt_size is not used
anymore.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
None of these routines were ever used anywhere in the kernel tree
since they were added to the kernel.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Merge our fixes branch into next, this brings in a number of commits
that fix bugs we don't want to hit in next, in particular the fix for
CVE-2019-12817.
This sets the HAVE_ARCH_HUGE_VMAP option, and defines the required
page table functions.
This enables huge (2MB and 1GB) ioremap mappings. I don't have a
benchmark for this change, but huge vmap will be used by a later core
kernel change to enable huge vmalloc memory mappings. This improves
cached `git diff` performance by about 5% on a 2-node POWER9 with 32MB
size dentry cache hash.
Profiling git diff dTLB misses with a vanilla kernel:
81.75% git [kernel.vmlinux] [k] __d_lookup_rcu
7.21% git [kernel.vmlinux] [k] strncpy_from_user
1.77% git [kernel.vmlinux] [k] find_get_entry
1.59% git [kernel.vmlinux] [k] kmem_cache_free
40,168 dTLB-miss
0.100342754 seconds time elapsed
With powerpc huge vmalloc:
2,987 dTLB-miss
0.095933138 seconds time elapsed
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Radix can use ioremap_page_range for ioremap, after slab is available.
This makes it possible to enable huge ioremap mapping support.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
One fix for a regression introduced by our 32-bit KASAN support, which broke
booting on machines with "bootx" early debugging enabled.
A fix for a bug which broke kexec on 32-bit, introduced by changes to the 32-bit
STRICT_KERNEL_RWX support in v5.1.
Finally two fixes going to stable for our THP split/collapse handling,
discovered by Nick. The first fixes random crashes and/or corruption in guests
under sufficient load.
Thanks to:
Nicholas Piggin, Christophe Leroy, Aaro Koskinen, Mathieu Malaterre.
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Merge tag 'powerpc-5.2-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc fixes from Michael Ellerman:
"One fix for a regression introduced by our 32-bit KASAN support, which
broke booting on machines with "bootx" early debugging enabled.
A fix for a bug which broke kexec on 32-bit, introduced by changes to
the 32-bit STRICT_KERNEL_RWX support in v5.1.
Finally two fixes going to stable for our THP split/collapse handling,
discovered by Nick. The first fixes random crashes and/or corruption
in guests under sufficient load.
Thanks to: Nicholas Piggin, Christophe Leroy, Aaro Koskinen, Mathieu
Malaterre"
* tag 'powerpc-5.2-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
powerpc/32s: fix booting with CONFIG_PPC_EARLY_DEBUG_BOOTX
powerpc/64s: __find_linux_pte() synchronization vs pmdp_invalidate()
powerpc/64s: Fix THP PMD collapse serialisation
powerpc: Fix kexec failure on book3s/32
Commit 1b2443a547 ("powerpc/book3s64: Avoid multiple endian
conversion in pte helpers") changed the actual bitwise tests in
pte_access_permitted by using pte_write() and pte_present() helpers
rather than raw bitwise testing _PAGE_WRITE and _PAGE_PRESENT bits.
The pte_present() change now returns true for PTEs which are
!_PAGE_PRESENT and _PAGE_INVALID, which is the combination used by
pmdp_invalidate() to synchronize access from lock-free lookups.
pte_access_permitted() is used by pmd_access_permitted(), so allowing
GUP lock free access to proceed with such PTEs breaks this
synchronisation.
This bug has been observed on a host using the hash page table MMU,
with random crashes and corruption in guests, usually together with
bad PMD messages in the host.
Fix this by adding an explicit check in pmd_access_permitted(), and
documenting the condition explicitly.
The pte_write() change should be okay, and would prevent GUP from
falling back to the slow path when encountering savedwrite PTEs, which
matches what x86 (that does not implement savedwrite) does.
Fixes: 1b2443a547 ("powerpc/book3s64: Avoid multiple endian conversion in pte helpers")
Cc: stable@vger.kernel.org # v4.20+
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-or-later
has been chosen to replace the boilerplate/reference in 3029 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
One fix going back to stable, for a bug on 32-bit introduced when we added
support for THREAD_INFO_IN_TASK.
A fix for a typo in a recent rework of our hugetlb code that leads to crashes on
64-bit when using hugetlbfs with a 4K PAGE_SIZE.
Two fixes for our recent rework of the address layout on 64-bit hash CPUs, both
only triggered when userspace tries to access addresses outside the user or
kernel address ranges.
Finally a fix for a recently introduced double free in an error path in our
cacheinfo code.
Thanks to:
Aneesh Kumar K.V, Christophe Leroy, Sachin Sant, Tobin C. Harding.
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Merge tag 'powerpc-5.2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc fixes from Michael Ellerman:
"One fix going back to stable, for a bug on 32-bit introduced when we
added support for THREAD_INFO_IN_TASK.
A fix for a typo in a recent rework of our hugetlb code that leads to
crashes on 64-bit when using hugetlbfs with a 4K PAGE_SIZE.
Two fixes for our recent rework of the address layout on 64-bit hash
CPUs, both only triggered when userspace tries to access addresses
outside the user or kernel address ranges.
Finally a fix for a recently introduced double free in an error path
in our cacheinfo code.
Thanks to: Aneesh Kumar K.V, Christophe Leroy, Sachin Sant, Tobin C.
Harding"
* tag 'powerpc-5.2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
powerpc/cacheinfo: Remove double free
powerpc/mm/hash: Fix get_region_id() for invalid addresses
powerpc/mm: Drop VM_BUG_ON in get_region_id()
powerpc/mm: Fix crashes with hugepages & 4K pages
powerpc/32s: fix flush_hash_pages() on SMP
Accesses by userspace to random addresses outside the user or kernel
address range will generate an SLB fault. When we handle that fault we
classify the effective address into several classes, eg. user, kernel
linear, kernel virtual etc.
For addresses that are completely outside of any valid range, we
should not insert an SLB entry at all, and instead immediately an
exception.
In the past this was handled in two ways. Firstly we would check the
top nibble of the address (using REGION_ID(ea)) and that would tell us
if the address was user (0), kernel linear (c), kernel virtual (d), or
vmemmap (f). If the address didn't match any of these it was invalid.
Then for each type of address we would do a secondary check. For the
user region we check against H_PGTABLE_RANGE, for kernel linear we
would mask the top nibble of the address and then check the address
against MAX_PHYSMEM_BITS.
As part of commit 0034d395f8 ("powerpc/mm/hash64: Map all the kernel
regions in the same 0xc range") we replaced REGION_ID() with
get_region_id() and changed the masking of the top nibble to only mask
the top two bits, which introduced a bug.
Addresses less than (4 << 60) are still handled correctly, they are
either less than (1 << 60) in which case they are subject to the
H_PGTABLE_RANGE check, or they are correctly checked against
MAX_PHYSMEM_BITS.
However addresses from (4 << 60) to ((0xc << 60) - 1), are incorrectly
treated as kernel linear addresses in get_region_id(). Then the top
two bits are cleared by EA_MASK in slb_allocate_kernel() and the
address is checked against MAX_PHYSMEM_BITS, which it passes due to
the masking. The end result is we incorrectly insert SLB entries for
those addresses.
That is not actually catastrophic, having inserted the SLB entry we
will then go on to take a page fault for the address and at that point
we detect the problem and report it as a bad fault.
Still we should not be inserting those entries, or treating them as
kernel linear addresses in the first place. So fix get_region_id() to
detect addresses in that range and return an invalid region id, which
we cause use to not insert an SLB entry and directly report an
exception.
Fixes: 0034d395f8 ("powerpc/mm/hash64: Map all the kernel regions in the same 0xc range")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
[mpe: Drop change to EA_MASK for now, rewrite change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
We call get_region_id() without validating the ea value. That means
with a wrong ea value we hit the BUG as below.
kernel BUG at arch/powerpc/include/asm/book3s/64/hash.h:129!
Oops: Exception in kernel mode, sig: 5 [#1]
LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
CPU: 0 PID: 3937 Comm: access_tests Not tainted 5.1.0
....
NIP [c00000000007ba20] do_slb_fault+0x70/0x320
LR [c00000000000896c] data_access_slb_common+0x15c/0x1a0
Fix this by removing the VM_BUG_ON. All callers make sure the returned
region id is valid and error out otherwise.
Fixes: 0034d395f8 ("powerpc/mm/hash64: Map all the kernel regions in the same 0xc range")
Reported-by: Andrew Donnellan <ajd@linux.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
On systems without CONTIG_ALLOC activated but that support gigantic pages,
boottime reserved gigantic pages can not be freed at all. This patch
simply enables the possibility to hand back those pages to memory
allocator.
Link: http://lkml.kernel.org/r/20190327063626.18421-5-alex@ghiti.fr
Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
Acked-by: David S. Miller <davem@davemloft.net> [sparc]
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andy Lutomirsky <luto@kernel.org>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When implementing the KUAP support on Radix we fixed one case where
mmu_has_feature() was being called too early in boot via
__put_user_size().
However since then some new code in linux-next has created a new path
via which we can end up calling mmu_has_feature() too early.
On P9 this leads to crashes early in boot if we have both PPC_KUAP and
CONFIG_JUMP_LABEL_FEATURE_CHECK_DEBUG enabled. Our early boot code
calls printk() which calls probe_kernel_read(), that does a
__copy_from_user_inatomic() which calls into set_kuap() and that uses
mmu_has_feature().
At that point in boot we haven't patched MMU features yet so the debug
code in mmu_has_feature() complains, and calls printk(). At that point
we recurse, eg:
...
dump_stack+0xdc
probe_kernel_read+0x1a4
check_pointer+0x58
...
printk+0x40
dump_stack_print_info+0xbc
dump_stack+0x8
probe_kernel_read+0x1a4
probe_kernel_read+0x19c
check_pointer+0x58
...
printk+0x40
cpufeatures_process_feature+0xc8
scan_cpufeatures_subnodes+0x380
of_scan_flat_dt_subnodes+0xb4
dt_cpu_ftrs_scan_callback+0x158
of_scan_flat_dt+0xf0
dt_cpu_ftrs_scan+0x3c
early_init_devtree+0x360
early_setup+0x9c
And so on for infinity, symptom is a dead system.
Even more fun is what happens when using the hash MMU (ie. p8 or p9
with Radix disabled), and when we don't have
CONFIG_JUMP_LABEL_FEATURE_CHECK_DEBUG enabled. With the debug disabled
we don't check if static keys have been initialised, we just rely on
the jump label. But the jump label defaults to true so we just whack
the AMR even though Radix is not enabled.
Clearing the AMR is fine, but after we've done the user copy we write
(0b11 << 62) into AMR. When using hash that makes all pages with key
zero no longer readable or writable. All kernel pages implicitly have
key zero, and so all of a sudden the kernel can't read or write any of
its memory. Again dead system.
In the medium term we have several options for fixing this.
probe_kernel_read() doesn't need to touch AMR at all, it's not doing a
user access after all, but it uses __copy_from_user_inatomic() just
because it's easy, we could fix that.
It would also be safe to default to not writing to the AMR during
early boot, until we've detected features. But it's not clear that
flipping all the MMU features to static_key_false won't introduce
other bugs.
But for now just switch to early_mmu_has_feature() in set_kuap(), that
avoids all the problems with jump labels. It adds the overhead of a
global lookup and test, but that's probably trivial compared to the
writes to the AMR anyway.
Fixes: 890274c2dc ("powerpc/64s: Implement KUAP for Radix MMU")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Russell Currey <ruscur@russell.cc>
When we add KASAN shadow area, KVIRT_TOP can't be anymore fixed
at 0xfe000000.
This patch uses FIXADDR_START to define KVIRT_TOP.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
