The kernel page table caches are tied to init_mm, so there is no
more need for them after userspace is finished.
destroy_context() gets called when we drop the last reference for an
mm, which can be much later than the task exit due to other lazy mm
references to it. We can free the page table cache pages on task exit
because they only cache the userspace page tables and kernel threads
should not access user space addresses.
The mapping for kernel threads itself is maintained in init_mm and
page table cache for that is attached to init_mm.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
[mpe: Merge change log additions from Aneesh]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
mmu_init_secondary() calls ppc44x_pin_tlb() which is marked __init,
leading to a warning:
The function mmu_init_secondary() references
the function __init ppc44x_pin_tlb().
There's no CPU hotplug support on 44x so mmu_init_secondary() will
only be called at boot. Therefore we should mark it as __init.
Signed-off-by: Alexey Spirkov <alexeis@astrosoft.ru>
[mpe: Flesh out change log details]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
asm/tlbflush.h is only needed for:
- using functions xxx_flush_tlb_xxx()
- using MMU_NO_CONTEXT
- including asm-generic/pgtable.h
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Files not using fixmap consts or functions don't need asm/fixmap.h
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
files not using feature fixup don't need asm/feature-fixups.h
files using feature fixup need asm/feature-fixups.h
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This patch moves ASM_CONST() and stringify_in_c() into
dedicated asm-const.h, then cleans all related inclusions.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
[mpe: asm-compat.h should include asm-const.h]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
We do this in some part. This patch make sure we always try to search
for hpte without holding lock and redo the compare with lock held once
match found.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
When computing the starting slot number for a hash page table group we used
to do this
hpte_group = ((hash & htab_hash_mask) * HPTES_PER_GROUP) & ~0x7UL;
Multiplying with 8 (HPTES_PER_GROUP) imply the last three bits are 0. Hence we
really don't need to clear then separately.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Applications need the ability to associate an address-range with some
key and latter revert to its initial default key. Pkey-0 comes close to
providing this function but falls short, because the current
implementation disallows applications to explicitly associate pkey-0 to
the address range.
Lets make pkey-0 less special and treat it almost like any other key.
Thus it can be explicitly associated with any address range, and can be
freed. This gives the application more flexibility and power. The
ability to free pkey-0 must be used responsibily, since pkey-0 is
associated with almost all address-range by default.
Even with this change pkey-0 continues to be slightly more special
from the following point of view.
(a) it is implicitly allocated.
(b) it is the default key assigned to any address-range.
(c) its permissions cannot be modified by userspace.
NOTE: (c) is specific to powerpc only. pkey-0 is associated by default
with all pages including kernel pages, and pkeys are also active in
kernel mode. If any permission is denied on pkey-0, the kernel running
in the context of the application will be unable to operate.
Tested on powerpc.
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
[mpe: Drop #define PKEY_0 0 in favour of plain old 0]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
execute-only key is allocated dynamically. This is a problem. When a
thread implicitly creates an execute-only key, and resets the UAMOR
for that key, the UAMOR value does not percolate to all the other
threads. Any other thread may ignorantly change the permissions on the
key. This can cause the key to be not execute-only for that thread.
Preallocate the execute-only key and ensure that no thread can change
the permission of the key, by resetting the corresponding bit in
UAMOR.
Fixes: 5586cf61e1 ("powerpc: introduce execute-only pkey")
Cc: stable@vger.kernel.org # v4.16+
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Total number of pkeys calculation is off by 1. Fix it.
Fixes: 4fb158f65a ("powerpc: track allocation status of all pkeys")
Cc: stable@vger.kernel.org # v4.16+
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Key allocation and deallocation has the side effect of programming the
UAMOR/AMR/IAMR registers. This is wrong, since its the responsibility of
the application and not that of the kernel, to modify the permission on
the key.
Do not modify the pkey registers at key allocation/deallocation.
This patch also fixes a bug where a sys_pkey_free() resets the UAMOR
bits of the key, thus making its permissions unmodifiable from user
space. Later if the same key gets reallocated from a different thread
this thread will no longer be able to change the permissions on the key.
Fixes: cf43d3b264 ("powerpc: Enable pkey subsystem")
Cc: stable@vger.kernel.org # v4.16+
Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Deny all permissions on all keys, with some exceptions. pkey-0 must
allow all permissions, or else everything comes to a screaching halt.
Execute-only key must allow execute permission.
Fixes: cf43d3b264 ("powerpc: Enable pkey subsystem")
Cc: stable@vger.kernel.org # v4.16+
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Currently in a multithreaded application, a key allocated by one
thread is not usable by other threads. By "not usable" we mean that
other threads are unable to change the access permissions for that
key for themselves.
When a new key is allocated in one thread, the corresponding UAMOR
bits for that thread get enabled, however the UAMOR bits for that key
for all other threads remain disabled.
Other threads have no way to set permissions on the key, and the
current default permissions are that read/write is enabled for all
keys, which means the key has no effect for other threads. Although
that may be the desired behaviour in some circumstances, having all
threads able to control their permissions for the key is more
flexible.
The current behaviour also differs from the x86 behaviour, which is
problematic for users.
To fix this, enable the UAMOR bits for all keys, at process
creation (in start_thread(), ie exec time). Since the contents of
UAMOR are inherited at fork, all threads are capable of modifying the
permissions on any key.
This is technically an ABI break on powerpc, but pkey support is fairly
new on powerpc and not widely used, and this brings us into
line with x86.
Fixes: cf43d3b264 ("powerpc: Enable pkey subsystem")
Cc: stable@vger.kernel.org # v4.16+
Tested-by: Florian Weimer <fweimer@redhat.com>
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
[mpe: Reword some of the changelog]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The HUGEPD_*_SHIFT macros are always defined to be PGDIR_SHIFT and
PUD_SHIFT, and have to have those values to work properly. They once used
to have different values, but that was really only because they were used
to mean different things in different contexts.
6fa50483 "powerpc/mm/hugetlb: initialize the pagetable cache correctly for
hugetlb" removed that double meaning, but left the now useless constants.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Merge in some commits we're sharing with the KVM tree.
I manually propagated the change from commit d3d4ffaae4
("powerpc/powernv/ioda2: Reduce upper limit for DMA window size") into
pci-ioda-tce.c.
Conflicts:
arch/powerpc/include/asm/cputable.h
arch/powerpc/platforms/powernv/pci-ioda.c
arch/powerpc/platforms/powernv/pci.h
POWER9 DD1 was never a product. It is no longer supported by upstream
firmware, and it is not effectively supported in Linux due to lack of
testing.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Michael Ellerman <mpe@ellerman.id.au>
[mpe: Remove arch_make_huge_pte() entirely]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
- introduce __diag_* macros and suppress -Wattribute-alias warnings from GCC 8
- fix stack protector test script for x86_64
- fix line number handling in Kconfig
- document that '#' starts a comment in Kconfig
- handle P_SYMBOL property in dump debugging of Kconfig
- correct help message of LD_DEAD_CODE_DATA_ELIMINATION
- fix occasional segmentation faults in Kconfig
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Merge tag 'kbuild-fixes-v4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild fixes from Masahiro Yamada:
- introduce __diag_* macros and suppress -Wattribute-alias warnings
from GCC 8
- fix stack protector test script for x86_64
- fix line number handling in Kconfig
- document that '#' starts a comment in Kconfig
- handle P_SYMBOL property in dump debugging of Kconfig
- correct help message of LD_DEAD_CODE_DATA_ELIMINATION
- fix occasional segmentation faults in Kconfig
* tag 'kbuild-fixes-v4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
kconfig: loop boundary condition fix
kbuild: reword help of LD_DEAD_CODE_DATA_ELIMINATION
kconfig: handle P_SYMBOL in print_symbol()
kconfig: document Kconfig source file comments
kconfig: fix line numbers for if-entries in menu tree
stack-protector: Fix test with 32-bit userland and CONFIG_64BIT=y
powerpc: Remove -Wattribute-alias pragmas
disable -Wattribute-alias warning for SYSCALL_DEFINEx()
kbuild: add macro for controlling warnings to linux/compiler.h
With SYSCALL_DEFINEx() disabling -Wattribute-alias generically, there's
no need to duplicate that for PowerPC syscalls.
This reverts commit 4155203739 ("powerpc: fix build failure by
disabling attribute-alias warning in pci_32") and commit 2479bfc9bc
("powerpc: Fix build by disabling attribute-alias warning for
SYSCALL_DEFINEx").
Signed-off-by: Paul Burton <paul.burton@mips.com>
Acked-by: Christophe Leroy <christophe.leroy@c-s.fr>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
With 4k page size for hugetlb we allocate hugepage directories from its on slab
cache. With patch 0c4d26802 ("powerpc/book3s64/mm: Simplify the rcu callback for page table free")
we missed to free these allocated hugepd tables.
Update pgtable_free to handle hugetlb hugepd directory table.
Fixes: 0c4d268029 ("powerpc/book3s64/mm: Simplify the rcu callback for page table free")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
[mpe: Add CONFIG_HUGETLB_PAGE guard to fix build break]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
If possible CPUs are limited (e.g., by kexec), then the kvm prefetch
workaround function can access the paca pointer for a !possible CPU.
Fixes: d2e60075a3 ("powerpc/64: Use array of paca pointers and allocate pacas individually")
Cc: stable@kernel.org
Reported-by: Pridhiviraj Paidipeddi <ppaidipe@linux.vnet.ibm.com>
Tested-by: Pridhiviraj Paidipeddi <ppaidipe@linux.vnet.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The patch 99baac21e4 ("mm: fix MADV_[FREE|DONTNEED] TLB flush miss
problem") added a force flush mode to the mmu_gather flush, which
unconditionally flushes the entire address range being invalidated
(even if actual ptes only covered a smaller range), to solve a problem
with concurrent threads invalidating the same PTEs causing them to
miss TLBs that need flushing.
This does not work with powerpc that invalidates mmu_gather batches
according to page size. Have powerpc flush all possible page sizes in
the range if it encounters this concurrency condition.
Patch 4647706ebe ("mm: always flush VMA ranges affected by
zap_page_range") does add a TLB flush for all page sizes on powerpc for
the zap_page_range case, but that is to be removed and replaced with
the mmu_gather flush to avoid redundant flushing. It is also thought to
not cover other obscure race conditions:
https://lkml.kernel.org/r/BD3A0EBE-ECF4-41D4-87FA-C755EA9AB6BD@gmail.com
Hash does not have a problem because it invalidates TLBs inside the
page table locks.
Reported-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
With PHYS_ADDR_MAX there is now a type safe variant for all bits set.
Make use of it.
Patch created using a semantic patch as follows:
// <smpl>
@@
typedef phys_addr_t;
@@
-(phys_addr_t)ULLONG_MAX
+PHYS_ADDR_MAX
// </smpl>
Link: http://lkml.kernel.org/r/20180419214204.19322-1-stefan@agner.ch
Signed-off-by: Stefan Agner <stefan@agner.ch>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com> [arm64]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Notable changes:
- Support for split PMD page table lock on 64-bit Book3S (Power8/9).
- Add support for HAVE_RELIABLE_STACKTRACE, so we properly support live
patching again.
- Add support for patching barrier_nospec in copy_from_user() and syscall entry.
- A couple of fixes for our data breakpoints on Book3S.
- A series from Nick optimising TLB/mm handling with the Radix MMU.
- Numerous small cleanups to squash sparse/gcc warnings from Mathieu Malaterre.
- Several series optimising various parts of the 32-bit code from Christophe Leroy.
- Removal of support for two old machines, "SBC834xE" and "C2K" ("GEFanuc,C2K"),
which is why the diffstat has so many deletions.
And many other small improvements & fixes.
There's a few out-of-area changes. Some minor ftrace changes OK'ed by Steve, and
a fix to our powernv cpuidle driver. Then there's a series touching mm, x86 and
fs/proc/task_mmu.c, which cleans up some details around pkey support. It was
ack'ed/reviewed by Ingo & Dave and has been in next for several weeks.
Thanks to:
Akshay Adiga, Alastair D'Silva, Alexey Kardashevskiy, Al Viro, Andrew
Donnellan, Aneesh Kumar K.V, Anju T Sudhakar, Arnd Bergmann, Balbir Singh,
Cédric Le Goater, Christophe Leroy, Christophe Lombard, Colin Ian King, Dave
Hansen, Fabio Estevam, Finn Thain, Frederic Barrat, Gautham R. Shenoy, Haren
Myneni, Hari Bathini, Ingo Molnar, Jonathan Neuschäfer, Josh Poimboeuf,
Kamalesh Babulal, Madhavan Srinivasan, Mahesh Salgaonkar, Mark Greer, Mathieu
Malaterre, Matthew Wilcox, Michael Neuling, Michal Suchanek, Naveen N. Rao,
Nicholas Piggin, Nicolai Stange, Olof Johansson, Paul Gortmaker, Paul
Mackerras, Peter Rosin, Pridhiviraj Paidipeddi, Ram Pai, Rashmica Gupta, Ravi
Bangoria, Russell Currey, Sam Bobroff, Samuel Mendoza-Jonas, Segher
Boessenkool, Shilpasri G Bhat, Simon Guo, Souptick Joarder, Stewart Smith,
Thiago Jung Bauermann, Torsten Duwe, Vaibhav Jain, Wei Yongjun, Wolfram Sang,
Yisheng Xie, YueHaibing.
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Merge tag 'powerpc-4.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman:
"Notable changes:
- Support for split PMD page table lock on 64-bit Book3S (Power8/9).
- Add support for HAVE_RELIABLE_STACKTRACE, so we properly support
live patching again.
- Add support for patching barrier_nospec in copy_from_user() and
syscall entry.
- A couple of fixes for our data breakpoints on Book3S.
- A series from Nick optimising TLB/mm handling with the Radix MMU.
- Numerous small cleanups to squash sparse/gcc warnings from Mathieu
Malaterre.
- Several series optimising various parts of the 32-bit code from
Christophe Leroy.
- Removal of support for two old machines, "SBC834xE" and "C2K"
("GEFanuc,C2K"), which is why the diffstat has so many deletions.
And many other small improvements & fixes.
There's a few out-of-area changes. Some minor ftrace changes OK'ed by
Steve, and a fix to our powernv cpuidle driver. Then there's a series
touching mm, x86 and fs/proc/task_mmu.c, which cleans up some details
around pkey support. It was ack'ed/reviewed by Ingo & Dave and has
been in next for several weeks.
Thanks to: Akshay Adiga, Alastair D'Silva, Alexey Kardashevskiy, Al
Viro, Andrew Donnellan, Aneesh Kumar K.V, Anju T Sudhakar, Arnd
Bergmann, Balbir Singh, Cédric Le Goater, Christophe Leroy, Christophe
Lombard, Colin Ian King, Dave Hansen, Fabio Estevam, Finn Thain,
Frederic Barrat, Gautham R. Shenoy, Haren Myneni, Hari Bathini, Ingo
Molnar, Jonathan Neuschäfer, Josh Poimboeuf, Kamalesh Babulal,
Madhavan Srinivasan, Mahesh Salgaonkar, Mark Greer, Mathieu Malaterre,
Matthew Wilcox, Michael Neuling, Michal Suchanek, Naveen N. Rao,
Nicholas Piggin, Nicolai Stange, Olof Johansson, Paul Gortmaker, Paul
Mackerras, Peter Rosin, Pridhiviraj Paidipeddi, Ram Pai, Rashmica
Gupta, Ravi Bangoria, Russell Currey, Sam Bobroff, Samuel
Mendoza-Jonas, Segher Boessenkool, Shilpasri G Bhat, Simon Guo,
Souptick Joarder, Stewart Smith, Thiago Jung Bauermann, Torsten Duwe,
Vaibhav Jain, Wei Yongjun, Wolfram Sang, Yisheng Xie, YueHaibing"
* tag 'powerpc-4.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (251 commits)
powerpc/64s/radix: Fix missing ptesync in flush_cache_vmap
cpuidle: powernv: Fix promotion from snooze if next state disabled
powerpc: fix build failure by disabling attribute-alias warning in pci_32
ocxl: Fix missing unlock on error in afu_ioctl_enable_p9_wait()
powerpc-opal: fix spelling mistake "Uniterrupted" -> "Uninterrupted"
powerpc: fix spelling mistake: "Usupported" -> "Unsupported"
powerpc/pkeys: Detach execute_only key on !PROT_EXEC
powerpc/powernv: copy/paste - Mask SO bit in CR
powerpc: Remove core support for Marvell mv64x60 hostbridges
powerpc/boot: Remove core support for Marvell mv64x60 hostbridges
powerpc/boot: Remove support for Marvell mv64x60 i2c controller
powerpc/boot: Remove support for Marvell MPSC serial controller
powerpc/embedded6xx: Remove C2K board support
powerpc/lib: optimise PPC32 memcmp
powerpc/lib: optimise 32 bits __clear_user()
powerpc/time: inline arch_vtime_task_switch()
powerpc/Makefile: set -mcpu=860 flag for the 8xx
powerpc: Implement csum_ipv6_magic in assembly
powerpc/32: Optimise __csum_partial()
powerpc/lib: Adjust .balign inside string functions for PPC32
...
Disassociate the exec_key from a VMA if the VMA permission is not
PROT_EXEC anymore. Otherwise the exec_only key continues to be
associated with the vma, causing unexpected behavior.
The problem was reported on x86 by Shakeel Butt, which is also
applicable on powerpc.
Fixes: 5586cf61e1 ("powerpc: introduce execute-only pkey")
Cc: stable@vger.kernel.org # v4.16+
Reported-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Pull siginfo updates from Eric Biederman:
"This set of changes close the known issues with setting si_code to an
invalid value, and with not fully initializing struct siginfo. There
remains work to do on nds32, arc, unicore32, powerpc, arm, arm64, ia64
and x86 to get the code that generates siginfo into a simpler and more
maintainable state. Most of that work involves refactoring the signal
handling code and thus careful code review.
Also not included is the work to shrink the in kernel version of
struct siginfo. That depends on getting the number of places that
directly manipulate struct siginfo under control, as it requires the
introduction of struct kernel_siginfo for the in kernel things.
Overall this set of changes looks like it is making good progress, and
with a little luck I will be wrapping up the siginfo work next
development cycle"
* 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (46 commits)
signal/sh: Stop gcc warning about an impossible case in do_divide_error
signal/mips: Report FPE_FLTUNK for undiagnosed floating point exceptions
signal/um: More carefully relay signals in relay_signal.
signal: Extend siginfo_layout with SIL_FAULT_{MCEERR|BNDERR|PKUERR}
signal: Remove unncessary #ifdef SEGV_PKUERR in 32bit compat code
signal/signalfd: Add support for SIGSYS
signal/signalfd: Remove __put_user from signalfd_copyinfo
signal/xtensa: Use force_sig_fault where appropriate
signal/xtensa: Consistenly use SIGBUS in do_unaligned_user
signal/um: Use force_sig_fault where appropriate
signal/sparc: Use force_sig_fault where appropriate
signal/sparc: Use send_sig_fault where appropriate
signal/sh: Use force_sig_fault where appropriate
signal/s390: Use force_sig_fault where appropriate
signal/riscv: Replace do_trap_siginfo with force_sig_fault
signal/riscv: Use force_sig_fault where appropriate
signal/parisc: Use force_sig_fault where appropriate
signal/parisc: Use force_sig_mceerr where appropriate
signal/openrisc: Use force_sig_fault where appropriate
signal/nios2: Use force_sig_fault where appropriate
...
stale_map[] bits are only set in steal_context_smp() so
on UP processors this map is useless. Only manage it for SMP
processors.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
last_context is 16 on the 8xx, 65535 on the 47x and 255 on other ones.
The kernel is exclusively built for the 8xx, for the 47x or for
another processor so the last context can be defined as a constant
depending on the processor.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
[mpe: Reformat old comment]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
no_selective_tlbil hence the use of either steal_all_contexts()
or steal_context_up() depends on the subarch, it won't change
during run. Only the 8xx uses steal_all_contexts and CONFIG_PPC_8xx
is exclusive of other processors.
This patch replaces the test of no_selective_tlbil global var by
a test of CONFIG_PPC_8xx selection. It avoids the test and
removes unnecessary code.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
First context is now 1 for all supported platforms, so it
can be made a constant.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
When inserting SLB entries for EA above 512TB, we need to hard disable irq.
This will make sure we don't take a PMU interrupt that can possibly touch
user space address via a stack dump. To prevent this, we need to hard disable
the interrupt.
Also add a comment explaining why we don't need context synchronizing isync
with slbmte.
Fixes: f384796c4 ("powerpc/mm: Add support for handling > 512TB address in SLB miss")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
With split pmd page table lock enabled, we don't use mm->page_table_lock when
updating pmd entries. This patch update hugetlb path to use the right lock
when inserting huge page directory entries into page table.
ex: if we are using hugepd and inserting hugepd entry at the pmd level, we
use pmd_lockptr, which based on config can be split pmd lock.
For update huge page directory entries itself we use mm->page_table_lock. We
do have a helper huge_pte_lockptr() for that.
Fixes: 675d99529 ("powerpc/book3s64: Enable split pmd ptlock")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The stores to update the SLB shadow area must be made as they appear
in the C code, so that the hypervisor does not see an entry with
mismatched vsid and esid. Use WRITE_ONCE for this.
GCC has been observed to elide the first store to esid in the update,
which means that if the hypervisor interrupts the guest after storing
to vsid, it could see an entry with old esid and new vsid, which may
possibly result in memory corruption.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
When a single-threaded process has a non-local mm_cpumask, try to use
that point to flush the TLBs out of other CPUs in the cpumask.
An IPI is used for clearing remote CPUs for a few reasons:
- An IPI can end lazy TLB use of the mm, which is required to prevent
TLB entries being created on the remote CPU. The alternative is to
drop lazy TLB switching completely, which costs 7.5% in a context
switch ping-pong test betwee a process and kernel idle thread.
- An IPI can have remote CPUs flush the entire PID, but the local CPU
can flush a specific VA. tlbie would require over-flushing of the
local CPU (where the process is running).
- A single threaded process that is migrated to a different CPU is
likely to have a relatively small mm_cpumask, so IPI is reasonable.
No other thread can concurrently switch to this mm, because it must
have been given a reference to mm_users by the current thread before it
can use_mm. mm_users can be asynchronously incremented (by
mm_activate or mmget_not_zero), but those users must use remote mm
access and can't use_mm or access user address space. Existing code
makes the this assumption already, for example sparc64 has reset
mm_cpumask using this condition since the start of history, see
arch/sparc/kernel/smp_64.c.
This reduces tlbies for a kernel compile workload from 0.90M to 0.12M,
tlbiels are increased significantly due to the PID flushing for the
cleaning up remote CPUs, and increased local flushes (PID flushes take
128 tlbiels vs 1 tlbie).
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Implementing pte_update with pte_xchg (which uses cmpxchg) is
inefficient. A single larx/stcx. works fine, no need for the less
efficient cmpxchg sequence.
Then remove the memory barriers from the operation. There is a
requirement for TLB flushing to load mm_cpumask after the store
that reduces pte permissions, which is moved into the TLB flush
code.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The ISA suggests ptesync after setting a pte, to prevent a table walk
initiated by a subsequent access from missing that store and causing a
spurious fault. This is an architectual allowance that allows an
implementation's page table walker to be incoherent with the store
queue.
However there is no correctness problem in taking a spurious fault in
userspace -- the kernel copes with these at any time, so the updated
pte will be found eventually. Spurious kernel faults on vmap memory
must be avoided, so a ptesync is put into flush_cache_vmap.
On POWER9 so far I have not found a measurable window where this can
result in more minor faults, so as an optimisation, remove the costly
ptesync from pte updates. If an implementation benefits from ptesync,
it would be better to add it back in update_mmu_cache, so it's not
done for things like fork(2).
fork --fork --exec benchmark improved 5.2% (12400->13100).
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Prefetch the faulting address in update_mmu_cache to give the page
table walker perhaps 100 cycles head start as locks are dropped and
the interrupt completed.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Radix flushes the TLB when updating ptes to increase permissiveness
of protection (increase access authority). Book3S does not require
TLB flushing in this case, and it is not done on hash. This patch
avoids the flush for radix.
>From Power ISA v3.0B, p.1090:
Setting a Reference or Change Bit or Upgrading Access Authority
(PTE Subject to Atomic Hardware Updates)
If the only change being made to a valid PTE that is subject to
atomic hardware updates is to set the Reference or Change bit to 1
or to add access authorities, a simpler sequence suffices because
the translation hardware will refetch the PTE if an access is
attempted for which the only problems were reference and/or change
bits needing to be set or insufficient access authority.
The nest MMU on POWER9 does not re-fetch the PTE after such an access
attempt before faulting, so address spaces with a coprocessor
attached will continue to flush in these cases.
This reduces tlbies for a kernel compile workload from 1.28M to 0.95M,
tlbiels from 20.17M 19.68M.
fork --fork --exec benchmark improved 2.77% (12000->12300).
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
When relaxing access (read -> read_write update), pte needs to be marked invalid
to handle a nest MMU bug. We also need to do a tlb flush after the pte is
marked invalid before updating the pte with new access bits.
We also move tlb flush to platform specific __ptep_set_access_flags. This will
help us to gerid of unnecessary tlb flush on BOOK3S 64 later. We don't do that
in this patch. This also helps in avoiding multiple tlbies with coprocessor
attached.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
In later patch, we use the vma and psize to do tlb flush. Do the prototype
update in separate patch to make the review easy.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
In later patch we will update them which require them to be moved
to pgtable-radix.c. Keeping the function in radix.h results in
compile warning as below.
./arch/powerpc/include/asm/book3s/64/radix.h: In function ‘radix__ptep_set_access_flags’:
./arch/powerpc/include/asm/book3s/64/radix.h:196:28: error: dereferencing pointer to incomplete type ‘struct vm_area_struct’
struct mm_struct *mm = vma->vm_mm;
^~
./arch/powerpc/include/asm/book3s/64/radix.h:204:6: error: implicit declaration of function ‘atomic_read’; did you mean ‘__atomic_load’? [-Werror=implicit-function-declaration]
atomic_read(&mm->context.copros) > 0) {
^~~~~~~~~~~
__atomic_load
./arch/powerpc/include/asm/book3s/64/radix.h:204:21: error: dereferencing pointer to incomplete type ‘struct mm_struct’
atomic_read(&mm->context.copros) > 0) {
Instead of fixing header dependencies, we move the function to pgtable-radix.c
Also the function is now large to be a static inline . Doing the
move in separate patch helps in review.
No functional change in this patch. Only code movement.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
In a later patch, we want to update __ptep_set_access_flags take page size
arg. This makes ptep_set_access_flags only work with mmu_virtual_psize.
To simplify the code make huge_ptep_set_access_flags directly call
__ptep_set_access_flags so that we can compute the hugetlb page size in
hugetlb function.
Now that ptep_set_access_flags won't be called for hugetlb remove
the is_vm_hugetlb_page() check and add the assert of pte lock
unconditionally.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
GCC 8.1 emits warnings such as the following. As arch/powerpc code is
built with -Werror, this breaks the build with GCC 8.1.
In file included from arch/powerpc/kernel/pci_64.c:23:
./include/linux/syscalls.h:233:18: error: 'sys_pciconfig_iobase' alias
between functions of incompatible types 'long int(long int, long
unsigned int, long unsigned int)' and 'long int(long int, long int,
long int)' [-Werror=attribute-alias]
asmlinkage long sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) \
^~~
./include/linux/syscalls.h:222:2: note: in expansion of macro '__SYSCALL_DEFINEx'
__SYSCALL_DEFINEx(x, sname, __VA_ARGS__)
This patch inhibits those warnings.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
[mpe: Trim change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Trivial fix to remove the following sparse warnings:
arch/powerpc/kernel/module_32.c:112:74: warning: Using plain integer as NULL pointer
arch/powerpc/kernel/module_32.c:117:74: warning: Using plain integer as NULL pointer
drivers/macintosh/via-pmu.c:1155:28: warning: Using plain integer as NULL pointer
drivers/macintosh/via-pmu.c:1230:20: warning: Using plain integer as NULL pointer
drivers/macintosh/via-pmu.c:1385:36: warning: Using plain integer as NULL pointer
drivers/macintosh/via-pmu.c:1752:23: warning: Using plain integer as NULL pointer
drivers/macintosh/via-pmu.c:2084:19: warning: Using plain integer as NULL pointer
drivers/macintosh/via-pmu.c:2110:32: warning: Using plain integer as NULL pointer
drivers/macintosh/via-pmu.c:2167:19: warning: Using plain integer as NULL pointer
drivers/macintosh/via-pmu.c:2183:19: warning: Using plain integer as NULL pointer
drivers/macintosh/via-pmu.c:277:20: warning: Using plain integer as NULL pointer
arch/powerpc/platforms/powermac/setup.c:155:67: warning: Using plain integer as NULL pointer
arch/powerpc/platforms/powermac/setup.c:247:27: warning: Using plain integer as NULL pointer
arch/powerpc/platforms/powermac/setup.c:249:27: warning: Using plain integer as NULL pointer
arch/powerpc/platforms/powermac/setup.c:252:37: warning: Using plain integer as NULL pointer
arch/powerpc/mm/tlb_hash32.c:127:21: warning: Using plain integer as NULL pointer
arch/powerpc/mm/tlb_hash32.c:148:21: warning: Using plain integer as NULL pointer
arch/powerpc/mm/tlb_hash32.c:44:21: warning: Using plain integer as NULL pointer
arch/powerpc/mm/tlb_hash32.c:57:21: warning: Using plain integer as NULL pointer
arch/powerpc/mm/tlb_hash32.c:87:21: warning: Using plain integer as NULL pointer
arch/powerpc/kernel/btext.c:160:31: warning: Using plain integer as NULL pointer
arch/powerpc/kernel/btext.c:167:22: warning: Using plain integer as NULL pointer
arch/powerpc/kernel/btext.c:274:21: warning: Using plain integer as NULL pointer
arch/powerpc/kernel/btext.c:285:31: warning: Using plain integer as NULL pointer
arch/powerpc/include/asm/hugetlb.h:204:16: warning: Using plain integer as NULL pointer
arch/powerpc/mm/ppc_mmu_32.c:170:21: warning: Using plain integer as NULL pointer
arch/powerpc/platforms/powermac/pci.c:1227:23: warning: Using plain integer as NULL pointer
arch/powerpc/platforms/powermac/pci.c:65:24: warning: Using plain integer as NULL pointer
Also use `--fix` command line option from `script/checkpatch --strict` to
remove the following:
CHECK: Comparison to NULL could be written "!dispDeviceBase"
#72: FILE: arch/powerpc/kernel/btext.c:160:
+ if (dispDeviceBase == NULL)
CHECK: Comparison to NULL could be written "!vbase"
#80: FILE: arch/powerpc/kernel/btext.c:167:
+ if (vbase == NULL)
CHECK: Comparison to NULL could be written "!base"
#89: FILE: arch/powerpc/kernel/btext.c:274:
+ if (base == NULL)
CHECK: Comparison to NULL could be written "!dispDeviceBase"
#98: FILE: arch/powerpc/kernel/btext.c:285:
+ if (dispDeviceBase == NULL)
CHECK: Comparison to NULL could be written "strstr"
#117: FILE: arch/powerpc/kernel/module_32.c:117:
+ if (strstr(secstrings + sechdrs[i].sh_name, ".debug") != NULL)
CHECK: Comparison to NULL could be written "!Hash"
#130: FILE: arch/powerpc/mm/ppc_mmu_32.c:170:
+ if (Hash == NULL)
CHECK: Comparison to NULL could be written "Hash"
#143: FILE: arch/powerpc/mm/tlb_hash32.c:44:
+ if (Hash != NULL) {
CHECK: Comparison to NULL could be written "!Hash"
#152: FILE: arch/powerpc/mm/tlb_hash32.c:57:
+ if (Hash == NULL) {
CHECK: Comparison to NULL could be written "!Hash"
#161: FILE: arch/powerpc/mm/tlb_hash32.c:87:
+ if (Hash == NULL) {
CHECK: Comparison to NULL could be written "!Hash"
#170: FILE: arch/powerpc/mm/tlb_hash32.c:127:
+ if (Hash == NULL) {
CHECK: Comparison to NULL could be written "!Hash"
#179: FILE: arch/powerpc/mm/tlb_hash32.c:148:
+ if (Hash == NULL) {
ERROR: space required after that ';' (ctx:VxV)
#192: FILE: arch/powerpc/platforms/powermac/pci.c:65:
+ for (; node != NULL;node = node->sibling) {
CHECK: Comparison to NULL could be written "node"
#192: FILE: arch/powerpc/platforms/powermac/pci.c:65:
+ for (; node != NULL;node = node->sibling) {
CHECK: Comparison to NULL could be written "!region"
#201: FILE: arch/powerpc/platforms/powermac/pci.c:1227:
+ if (region == NULL)
CHECK: Comparison to NULL could be written "of_get_property"
#214: FILE: arch/powerpc/platforms/powermac/setup.c:155:
+ if (of_get_property(np, "cache-unified", NULL) != NULL && dc) {
CHECK: Comparison to NULL could be written "!np"
#223: FILE: arch/powerpc/platforms/powermac/setup.c:247:
+ if (np == NULL)
CHECK: Comparison to NULL could be written "np"
#226: FILE: arch/powerpc/platforms/powermac/setup.c:249:
+ if (np != NULL) {
CHECK: Comparison to NULL could be written "l2cr"
#230: FILE: arch/powerpc/platforms/powermac/setup.c:252:
+ if (l2cr != NULL) {
CHECK: Comparison to NULL could be written "via"
#243: FILE: drivers/macintosh/via-pmu.c:277:
+ if (via != NULL)
CHECK: Comparison to NULL could be written "current_req"
#252: FILE: drivers/macintosh/via-pmu.c:1155:
+ if (current_req != NULL) {
CHECK: Comparison to NULL could be written "!req"
#261: FILE: drivers/macintosh/via-pmu.c:1230:
+ if (req == NULL || pmu_state != idle
CHECK: Comparison to NULL could be written "!req"
#270: FILE: drivers/macintosh/via-pmu.c:1385:
+ if (req == NULL) {
CHECK: Comparison to NULL could be written "!pp"
#288: FILE: drivers/macintosh/via-pmu.c:2084:
+ if (pp == NULL)
CHECK: Comparison to NULL could be written "!pp"
#297: FILE: drivers/macintosh/via-pmu.c:2110:
+ if (count < 1 || pp == NULL)
CHECK: Comparison to NULL could be written "!pp"
#306: FILE: drivers/macintosh/via-pmu.c:2167:
+ if (pp == NULL)
CHECK: Comparison to NULL could be written "pp"
#315: FILE: drivers/macintosh/via-pmu.c:2183:
+ if (pp != NULL) {
Link: https://github.com/linuxppc/linux/issues/37
Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Commit a7a9dcd882 ("powerpc: Avoid taking a data miss on every
userspace instruction miss") has shown that limiting the read of
faulting instruction to likely cases improves performance.
This patch goes further into this direction by limiting the read
of the faulting instruction to the only cases where it is likely
needed.
On an MPC885, with the same benchmark app as in the commit referred
above, we see a reduction of about 3900 dTLB misses (approx 3%):
Before the patch:
Performance counter stats for './fault 500' (10 runs):
683033312 cpu-cycles ( +- 0.03% )
134538 dTLB-load-misses ( +- 0.03% )
46099 iTLB-load-misses ( +- 0.02% )
19681 faults ( +- 0.02% )
5.389747878 seconds time elapsed ( +- 0.06% )
With the patch:
Performance counter stats for './fault 500' (10 runs):
682112862 cpu-cycles ( +- 0.03% )
130619 dTLB-load-misses ( +- 0.03% )
46073 iTLB-load-misses ( +- 0.05% )
19681 faults ( +- 0.01% )
5.381342641 seconds time elapsed ( +- 0.07% )
The proper work of the huge stack expansion was tested with the
following app:
int main(int argc, char **argv)
{
char buf[1024 * 1025];
sprintf(buf, "Hello world !\n");
printf(buf);
exit(0);
}
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Add include of pagemap.h to fix build errors]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Use symbolic names defined in asm/ppc-opcode.h
instead of hardcoded values.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
