Pull pidfd updates from Christian Brauner:
"This introduces a new extension to the pidfd_open() syscall. Users can
now raise the new PIDFD_NONBLOCK flag to support non-blocking pidfd
file descriptors. This has been requested for uses in async process
management libraries such as async-pidfd in Rust.
Ever since the introduction of pidfds and more advanced async io
various programming languages such as Rust have grown support for
async event libraries. These libraries are created to help build
epoll-based event loops around file descriptors. A common pattern is
to automatically make all file descriptors they manage to O_NONBLOCK.
For such libraries the EAGAIN error code is treated specially. When a
function is called that returns EAGAIN the function isn't called again
until the event loop indicates the the file descriptor is ready.
Supporting EAGAIN when waiting on pidfds makes such libraries just
work with little effort.
This introduces a new flag PIDFD_NONBLOCK that is equivalent to
O_NONBLOCK. This follows the same patterns we have for other (anon
inode) file descriptors such as EFD_NONBLOCK, IN_NONBLOCK,
SFD_NONBLOCK, TFD_NONBLOCK and the same for close-on-exec flags.
Passing a non-blocking pidfd to waitid() currently has no effect, i.e.
is not supported. There are users which would like to use waitid() on
pidfds that are O_NONBLOCK and mix it with pidfds that are blocking
and both pass them to waitid().
The expected behavior is to have waitid() return -EAGAIN for
non-blocking pidfds and to block for blocking pidfds without needing
to perform any additional checks for flags set on the pidfd before
passing it to waitid(). Non-blocking pidfds will return EAGAIN from
waitid() when no child process is ready yet. Returning -EAGAIN for
non-blocking pidfds makes it easier for event loops that handle EAGAIN
specially.
It also makes the API more consistent and uniform. In essence,
waitid() is treated like a read on a non-blocking pidfd or a recvmsg()
on a non-blocking socket.
With the addition of support for non-blocking pidfds we support the
same functionality that sockets do. For sockets() recvmsg() supports
MSG_DONTWAIT for pidfds waitid() supports WNOHANG. Both flags are
per-call options. In contrast non-blocking pidfds and non-blocking
sockets are a setting on an open file description affecting all
threads in the calling process as well as other processes that hold
file descriptors referring to the same open file description. Both
behaviors, per call and per open file description, have genuine
use-cases.
The interaction with the WNOHANG flag is documented as follows:
- If a non-blocking pidfd is passed and WNOHANG is not raised we
simply raise the WNOHANG flag internally. When do_wait() returns
indicating that there are eligible child processes but none have
exited yet we set EAGAIN. If no child process exists we continue
returning ECHILD.
- If a non-blocking pidfd is passed and WNOHANG is raised waitid()
will continue returning 0, i.e. it will not set EAGAIN. This ensure
backwards compatibility with applications passing WNOHANG
explicitly with pidfds"
* tag 'threads-v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
tests: remove O_NONBLOCK before waiting for WSTOPPED
tests: add waitid() tests for non-blocking pidfds
tests: port pidfd_wait to kselftest harness
pidfd: support PIDFD_NONBLOCK in pidfd_open()
exit: support non-blocking pidfds
Pull kernel_clone() updates from Christian Brauner:
"During the v5.9 merge window we reworked the process creation
codepaths across multiple architectures. After this work we were only
left with the _do_fork() helper based on the struct kernel_clone_args
calling convention. As was pointed out _do_fork() isn't valid
kernelese especially for a helper that isn't just static.
This series removes the _do_fork() helper and introduces the new
kernel_clone() helper. The process creation cleanup didn't change the
name to something more reasonable mainly because _do_fork() was used
in quite a few places. So sending this as a separate series seemed the
better strategy.
I originally intended to send this early in the v5.9 development cycle
after the merge window had closed but given that this was touching
quite a few places I decided to defer this until the v5.10 merge
window"
* tag 'kernel-clone-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
sched: remove _do_fork()
tracing: switch to kernel_clone()
kgdbts: switch to kernel_clone()
kprobes: switch to kernel_clone()
x86: switch to kernel_clone()
sparc: switch to kernel_clone()
nios2: switch to kernel_clone()
m68k: switch to kernel_clone()
ia64: switch to kernel_clone()
h8300: switch to kernel_clone()
fork: introduce kernel_clone()
Pull kselftest updates from Shuah Khan:
- a selftests harness fix to flush stdout before forking to avoid
parent and child printing duplicates messages. This is evident when
test output is redirected to a file.
- a tools/ wide change to avoid comma separated statements from Joe
Perches. This fix spans tools/lib, tools/power/cpupower, and
selftests.
* tag 'linux-kselftest-fixes-5.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
tools: Avoid comma separated statements
selftests/harness: Flush stdout before forking
Merge misc updates from Andrew Morton:
"181 patches.
Subsystems affected by this patch series: kbuild, scripts, ntfs,
ocfs2, vfs, mm (slab, slub, kmemleak, dax, debug, pagecache, fadvise,
gup, swap, memremap, memcg, selftests, pagemap, mincore, hmm, dma,
memory-failure, vmallo and migration)"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (181 commits)
mm/migrate: remove obsolete comment about device public
mm/migrate: remove cpages-- in migrate_vma_finalize()
mm, oom_adj: don't loop through tasks in __set_oom_adj when not necessary
memblock: use separate iterators for memory and reserved regions
memblock: implement for_each_reserved_mem_region() using __next_mem_region()
memblock: remove unused memblock_mem_size()
x86/setup: simplify reserve_crashkernel()
x86/setup: simplify initrd relocation and reservation
arch, drivers: replace for_each_membock() with for_each_mem_range()
arch, mm: replace for_each_memblock() with for_each_mem_pfn_range()
memblock: reduce number of parameters in for_each_mem_range()
memblock: make memblock_debug and related functionality private
memblock: make for_each_memblock_type() iterator private
mircoblaze: drop unneeded NUMA and sparsemem initializations
riscv: drop unneeded node initialization
h8300, nds32, openrisc: simplify detection of memory extents
arm64: numa: simplify dummy_numa_init()
arm, xtensa: simplify initialization of high memory pages
dma-contiguous: simplify cma_early_percent_memory()
KVM: PPC: Book3S HV: simplify kvm_cma_reserve()
...
This patch reduces the running time for compaction_test from about 27 sec,
to 3.3 sec, which is about an 8x speedup.
These numbers are for an Intel x86_64 system with 32 GB of DRAM.
The compaction_test.c program was spending most of its time doing mmap(),
1 MB at a time, on about 25 GB of memory.
Instead, do the mmaps 100 MB at a time. (Going past 100 MB doesn't make
things go much faster, because other parts of the program are using the
remaining time.)
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Sri Jayaramappa <sjayaram@akamai.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Link: https://lkml.kernel.org/r/20201002080621.551044-2-jhubbard@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Avoid accidental wrong builds, due to built-in rules working just a little
bit too well--but not quite as well as required for our situation here.
In other words, "make userfaultfd" (for example) is supposed to fail to
build at all, because this Makefile only supports either "make" (all), or
"make /full/path". However, the built-in rules, if not suppressed, will
pick up CFLAGS and the initial LDLIBS (but not the target-specific LDLIBS,
because those are only set for the full path target!). This causes it to
get pretty far into building things despite using incorrect values such as
an *occasionally* incomplete LDLIBS value.
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Link: https://lkml.kernel.org/r/20200915012901.1655280-3-jhubbard@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "selftests/vm: fix some minor aggravating factors in the Makefile".
This fixes a couple of minor aggravating factors that I ran across while
trying to do some changes in selftests/vm. These are simple things, but
like most things with GNU Make, it's rarely obvious what's wrong until you
understand *the entire Makefile and all of its includes*.
So while there is, of course, joy in learning those details, I thought I'd
fix these little things, so as to allow others to skip out on the Joy if
they so choose. :)
First of all, if you have an item (let's choose userfaultfd for an
example) that fails to build, you might do this:
$ make -j32
# ...you observe a failed item in the threaded output
# OK, let's get a closer look
$ make
# ...but now the build quietly "succeeds".
That's what Patch 0001 fixes.
Second, if you instead attempt this approach for your closer look (a casual
mistake, as it's not supported):
$ make userfaultfd
# ...userfaultfd fails to link, due to incomplete LDLIBS
That's what Patch 0002 fixes.
This patch (of 2):
If one or more of these selftest fail to build, then after the first
failure, subsequent invocations of "make" will make it appear that there
are no build failures, after all.
That's because the failed build products remain, with up-to-date
timestamps, thus tricking Make (and you!) into believing that there's
nothing else to build.
Fix this by telling Make to delete targets that didn't completely
succeed.
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Link: https://lkml.kernel.org/r/20200915012901.1655280-1-jhubbard@nvidia.com
Link: https://lkml.kernel.org/r/20200915012901.1655280-2-jhubbard@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull seccomp updates from Kees Cook:
"The bulk of the changes are with the seccomp selftests to accommodate
some powerpc-specific behavioral characteristics. Additional cleanups,
fixes, and improvements are also included:
- heavily refactor seccomp selftests (and clone3 selftests
dependency) to fix powerpc (Kees Cook, Thadeu Lima de Souza
Cascardo)
- fix style issue in selftests (Zou Wei)
- upgrade "unknown action" from KILL_THREAD to KILL_PROCESS (Rich
Felker)
- replace task_pt_regs(current) with current_pt_regs() (Denis
Efremov)
- fix corner-case race in USER_NOTIF (Jann Horn)
- make CONFIG_SECCOMP no longer per-arch (YiFei Zhu)"
* tag 'seccomp-v5.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (23 commits)
seccomp: Make duplicate listener detection non-racy
seccomp: Move config option SECCOMP to arch/Kconfig
selftests/clone3: Avoid OS-defined clone_args
selftests/seccomp: powerpc: Set syscall return during ptrace syscall exit
selftests/seccomp: Allow syscall nr and ret value to be set separately
selftests/seccomp: Record syscall during ptrace entry
selftests/seccomp: powerpc: Fix seccomp return value testing
selftests/seccomp: Remove SYSCALL_NUM_RET_SHARE_REG in favor of SYSCALL_RET_SET
selftests/seccomp: Avoid redundant register flushes
selftests/seccomp: Convert REGSET calls into ARCH_GETREG/ARCH_SETREG
selftests/seccomp: Convert HAVE_GETREG into ARCH_GETREG/ARCH_SETREG
selftests/seccomp: Remove syscall setting #ifdefs
selftests/seccomp: mips: Remove O32-specific macro
selftests/seccomp: arm64: Define SYSCALL_NUM_SET macro
selftests/seccomp: arm: Define SYSCALL_NUM_SET macro
selftests/seccomp: mips: Define SYSCALL_NUM_SET macro
selftests/seccomp: Provide generic syscall setting macro
selftests/seccomp: Refactor arch register macros to avoid xtensa special case
selftests/seccomp: Use __NR_mknodat instead of __NR_mknod
selftests/seccomp: Use bitwise instead of arithmetic operator for flags
...
Pull scheduler updates from Ingo Molnar:
- reorganize & clean up the SD* flags definitions and add a bunch of
sanity checks. These new checks caught quite a few bugs or at least
inconsistencies, resulting in another set of patches.
- rseq updates, add MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ
- add a new tracepoint to improve CPU capacity tracking
- improve overloaded SMP system load-balancing behavior
- tweak SMT balancing
- energy-aware scheduling updates
- NUMA balancing improvements
- deadline scheduler fixes and improvements
- CPU isolation fixes
- misc cleanups, simplifications and smaller optimizations
* tag 'sched-core-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (42 commits)
sched/deadline: Unthrottle PI boosted threads while enqueuing
sched/debug: Add new tracepoint to track cpu_capacity
sched/fair: Tweak pick_next_entity()
rseq/selftests: Test MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ
rseq/selftests,x86_64: Add rseq_offset_deref_addv()
rseq/membarrier: Add MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ
sched/fair: Use dst group while checking imbalance for NUMA balancer
sched/fair: Reduce busy load balance interval
sched/fair: Minimize concurrent LBs between domain level
sched/fair: Reduce minimal imbalance threshold
sched/fair: Relax constraint on task's load during load balance
sched/fair: Remove the force parameter of update_tg_load_avg()
sched/fair: Fix wrong cpu selecting from isolated domain
sched: Remove unused inline function uclamp_bucket_base_value()
sched/rt: Disable RT_RUNTIME_SHARE by default
sched/deadline: Fix stale throttling on de-/boosted tasks
sched/numa: Use runnable_avg to classify node
sched/topology: Move sd_flag_debug out of #ifdef CONFIG_SYSCTL
MAINTAINERS: Add myself as SCHED_DEADLINE reviewer
sched/topology: Move SD_DEGENERATE_GROUPS_MASK out of linux/sched/topology.h
...
Pull x86 fsgsbase updates from Borislav Petkov:
"Misc minor cleanups and corrections to the fsgsbase code and
respective selftests"
* tag 'x86_fsgsbase_for_v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
selftests/x86/fsgsbase: Test PTRACE_PEEKUSER for GSBASE with invalid LDT GS
selftests/x86/fsgsbase: Reap a forgotten child
x86/fsgsbase: Replace static_cpu_has() with boot_cpu_has()
x86/entry/64: Correct the comment over SAVE_AND_SET_GSBASE
Pull RAS updates from Borislav Petkov:
- Extend the recovery from MCE in kernel space also to processes which
encounter an MCE in kernel space but while copying from user memory
by sending them a SIGBUS on return to user space and umapping the
faulty memory, by Tony Luck and Youquan Song.
- memcpy_mcsafe() rework by splitting the functionality into
copy_mc_to_user() and copy_mc_to_kernel(). This, as a result, enables
support for new hardware which can recover from a machine check
encountered during a fast string copy and makes that the default and
lets the older hardware which does not support that advance recovery,
opt in to use the old, fragile, slow variant, by Dan Williams.
- New AMD hw enablement, by Yazen Ghannam and Akshay Gupta.
- Do not use MSR-tracing accessors in #MC context and flag any fault
while accessing MCA architectural MSRs as an architectural violation
with the hope that such hw/fw misdesigns are caught early during the
hw eval phase and they don't make it into production.
- Misc fixes, improvements and cleanups, as always.
* tag 'ras_updates_for_v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mce: Allow for copy_mc_fragile symbol checksum to be generated
x86/mce: Decode a kernel instruction to determine if it is copying from user
x86/mce: Recover from poison found while copying from user space
x86/mce: Avoid tail copy when machine check terminated a copy from user
x86/mce: Add _ASM_EXTABLE_CPY for copy user access
x86/mce: Provide method to find out the type of an exception handler
x86/mce: Pass pointer to saved pt_regs to severity calculation routines
x86/copy_mc: Introduce copy_mc_enhanced_fast_string()
x86, powerpc: Rename memcpy_mcsafe() to copy_mc_to_{user, kernel}()
x86/mce: Drop AMD-specific "DEFERRED" case from Intel severity rule list
x86/mce: Add Skylake quirk for patrol scrub reported errors
RAS/CEC: Convert to DEFINE_SHOW_ATTRIBUTE()
x86/mce: Annotate mce_rd/wrmsrl() with noinstr
x86/mce/dev-mcelog: Do not update kflags on AMD systems
x86/mce: Stop mce_reign() from re-computing severity for every CPU
x86/mce: Make mce_rdmsrl() panic on an inaccessible MSR
x86/mce: Increase maximum number of banks to 64
x86/mce: Delay clearing IA32_MCG_STATUS to the end of do_machine_check()
x86/MCE/AMD, EDAC/mce_amd: Remove struct smca_hwid.xec_bitmap
RAS/CEC: Fix cec_init() prototype
Pull arm64 updates from Will Deacon:
"There's quite a lot of code here, but much of it is due to the
addition of a new PMU driver as well as some arm64-specific selftests
which is an area where we've traditionally been lagging a bit.
In terms of exciting features, this includes support for the Memory
Tagging Extension which narrowly missed 5.9, hopefully allowing
userspace to run with use-after-free detection in production on CPUs
that support it. Work is ongoing to integrate the feature with KASAN
for 5.11.
Another change that I'm excited about (assuming they get the hardware
right) is preparing the ASID allocator for sharing the CPU page-table
with the SMMU. Those changes will also come in via Joerg with the
IOMMU pull.
We do stray outside of our usual directories in a few places, mostly
due to core changes required by MTE. Although much of this has been
Acked, there were a couple of places where we unfortunately didn't get
any review feedback.
Other than that, we ran into a handful of minor conflicts in -next,
but nothing that should post any issues.
Summary:
- Userspace support for the Memory Tagging Extension introduced by
Armv8.5. Kernel support (via KASAN) is likely to follow in 5.11.
- Selftests for MTE, Pointer Authentication and FPSIMD/SVE context
switching.
- Fix and subsequent rewrite of our Spectre mitigations, including
the addition of support for PR_SPEC_DISABLE_NOEXEC.
- Support for the Armv8.3 Pointer Authentication enhancements.
- Support for ASID pinning, which is required when sharing
page-tables with the SMMU.
- MM updates, including treating flush_tlb_fix_spurious_fault() as a
no-op.
- Perf/PMU driver updates, including addition of the ARM CMN PMU
driver and also support to handle CPU PMU IRQs as NMIs.
- Allow prefetchable PCI BARs to be exposed to userspace using normal
non-cacheable mappings.
- Implementation of ARCH_STACKWALK for unwinding.
- Improve reporting of unexpected kernel traps due to BPF JIT
failure.
- Improve robustness of user-visible HWCAP strings and their
corresponding numerical constants.
- Removal of TEXT_OFFSET.
- Removal of some unused functions, parameters and prototypes.
- Removal of MPIDR-based topology detection in favour of firmware
description.
- Cleanups to handling of SVE and FPSIMD register state in
preparation for potential future optimisation of handling across
syscalls.
- Cleanups to the SDEI driver in preparation for support in KVM.
- Miscellaneous cleanups and refactoring work"
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (148 commits)
Revert "arm64: initialize per-cpu offsets earlier"
arm64: random: Remove no longer needed prototypes
arm64: initialize per-cpu offsets earlier
kselftest/arm64: Check mte tagged user address in kernel
kselftest/arm64: Verify KSM page merge for MTE pages
kselftest/arm64: Verify all different mmap MTE options
kselftest/arm64: Check forked child mte memory accessibility
kselftest/arm64: Verify mte tag inclusion via prctl
kselftest/arm64: Add utilities and a test to validate mte memory
perf: arm-cmn: Fix conversion specifiers for node type
perf: arm-cmn: Fix unsigned comparison to less than zero
arm64: dbm: Invalidate local TLB when setting TCR_EL1.HD
arm64: mm: Make flush_tlb_fix_spurious_fault() a no-op
arm64: Add support for PR_SPEC_DISABLE_NOEXEC prctl() option
arm64: Pull in task_stack_page() to Spectre-v4 mitigation code
KVM: arm64: Allow patching EL2 vectors even with KASLR is not enabled
arm64: Get rid of arm64_ssbd_state
KVM: arm64: Convert ARCH_WORKAROUND_2 to arm64_get_spectre_v4_state()
KVM: arm64: Get rid of kvm_arm_have_ssbd()
KVM: arm64: Simplify handling of ARCH_WORKAROUND_2
...
Naresh reported that selftests: pidfd: pidfd_wait hangs on linux next kernel on
x86_64, i386 and arm64 Juno-r2
These devices are using NFS mounted rootfs.
I have tested pidfd testcases independently and all test PASS.
The Hang or exit from test run noticed when run by run_kselftest.sh
pidfd_wait.c:208:wait_nonblock:Expected sys_waitid(P_PIDFD, pidfd,
&info, WSTOPPED, NULL) (-1) == 0 (0)
wait_nonblock: Test terminated by assertion
metadata:
git branch: master
git repo: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
git commit: e64997027d5f171148687e58b78c8b3c869a6158
git describe: next-20200922
make_kernelversion: 5.9.0-rc6
kernel-config:
http://snapshots.linaro.org/openembedded/lkft/lkft/sumo/intel-core2-32/lkft/linux-next/865/config
The reason for this is a simple race in the selftests, that I overlooked and
which is more likely to hit when there's a lot of processes running on the
system. Basically the child process hasn't SIGSTOPed itself yet but the parent
is already calling waitid() on a O_NONBLOCK pidfd. Since it doesn't find a
WSTOPPED process it returns -EAGAIN correctly.
The fix for this is to move the line where we're removing the O_NONBLOCK
property from the fd before the waitid() WSTOPPED call so we hang until the
child becomes stopped.
Fixes: cd89597bbe ("tests: add waitid() tests for non-blocking pidfds")
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Link: https://lkft.validation.linaro.org/scheduler/job/1813223
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Late patches for 5.10: MTE selftests, minor KCSAN preparation and removal
of some unused prototypes.
(Amit Daniel Kachhap and others)
* for-next/late-arrivals:
arm64: random: Remove no longer needed prototypes
arm64: initialize per-cpu offsets earlier
kselftest/arm64: Check mte tagged user address in kernel
kselftest/arm64: Verify KSM page merge for MTE pages
kselftest/arm64: Verify all different mmap MTE options
kselftest/arm64: Check forked child mte memory accessibility
kselftest/arm64: Verify mte tag inclusion via prctl
kselftest/arm64: Add utilities and a test to validate mte memory
In reaction to a proposal to introduce a memcpy_mcsafe_fast()
implementation Linus points out that memcpy_mcsafe() is poorly named
relative to communicating the scope of the interface. Specifically what
addresses are valid to pass as source, destination, and what faults /
exceptions are handled.
Of particular concern is that even though x86 might be able to handle
the semantics of copy_mc_to_user() with its common copy_user_generic()
implementation other archs likely need / want an explicit path for this
case:
On Fri, May 1, 2020 at 11:28 AM Linus Torvalds <torvalds@linux-foundation.org> wrote:
>
> On Thu, Apr 30, 2020 at 6:21 PM Dan Williams <dan.j.williams@intel.com> wrote:
> >
> > However now I see that copy_user_generic() works for the wrong reason.
> > It works because the exception on the source address due to poison
> > looks no different than a write fault on the user address to the
> > caller, it's still just a short copy. So it makes copy_to_user() work
> > for the wrong reason relative to the name.
>
> Right.
>
> And it won't work that way on other architectures. On x86, we have a
> generic function that can take faults on either side, and we use it
> for both cases (and for the "in_user" case too), but that's an
> artifact of the architecture oddity.
>
> In fact, it's probably wrong even on x86 - because it can hide bugs -
> but writing those things is painful enough that everybody prefers
> having just one function.
Replace a single top-level memcpy_mcsafe() with either
copy_mc_to_user(), or copy_mc_to_kernel().
Introduce an x86 copy_mc_fragile() name as the rename for the
low-level x86 implementation formerly named memcpy_mcsafe(). It is used
as the slow / careful backend that is supplanted by a fast
copy_mc_generic() in a follow-on patch.
One side-effect of this reorganization is that separating copy_mc_64.S
to its own file means that perf no longer needs to track dependencies
for its memcpy_64.S benchmarks.
[ bp: Massage a bit. ]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: <stable@vger.kernel.org>
Link: http://lore.kernel.org/r/CAHk-=wjSqtXAqfUJxFtWNwmguFASTgB0dz1dT3V-78Quiezqbg@mail.gmail.com
Link: https://lkml.kernel.org/r/160195561680.2163339.11574962055305783722.stgit@dwillia2-desk3.amr.corp.intel.com
Add a testcase to check that user address with valid/invalid
mte tag works in kernel mode. This test verifies that the kernel
API's __arch_copy_from_user/__arch_copy_to_user works by considering
if the user pointer has valid/invalid allocation tags.
In MTE sync mode, file memory read/write and other similar interfaces
fails if a user memory with invalid tag is accessed in kernel. In async
mode no such failure occurs.
Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
Tested-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201002115630.24683-7-amit.kachhap@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
