try_get_page() is very similar to try_get_compound_head(), and in fact
try_get_page() has fallen a little behind in terms of maintenance:
try_get_compound_head() handles speculative page references more
thoroughly.
There are only two try_get_page() callsites, so just call
try_get_compound_head() directly from those, and remove try_get_page()
entirely.
Also, seeing as how this changes try_get_compound_head() into a non-static
function, provide some kerneldoc documentation for it.
Link: https://lkml.kernel.org/r/20210813044133.1536842-4-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The struct pci_dev uses reference counting but zPCI assumed erroneously
that the last reference would always be the local reference after
calling pci_stop_and_remove_bus_device(). This is usually the case but
not how reference counting works and thus inherently fragile.
In fact one case where this causes a NULL pointer dereference when on an
SRIOV device the function 0 was hot unplugged before another function of
the same multi-function device. In this case the second function's
pdev->sriov->dev reference keeps the struct pci_dev of function 0 alive
even after the unplug. This bug was previously hidden by the fact that
we were leaking the struct pci_dev which in turn means that it always
outlived the struct zpci_dev. This was fixed in commit 0b13525c20
("s390/pci: fix leak of PCI device structure") exposing the broken
behavior.
Fix this by accounting for the long living reference a struct pci_dev
has to its underlying struct zpci_dev via the zbus->function[] array and
only release that in pcibios_release_device() ensuring that the struct
pci_dev is not left with a dangling reference. This is a minimal fix in
the future it would probably better to use fine grained reference
counting for struct zpci_dev.
Fixes: 05bc1be6db ("s390/pci: create zPCI bus")
Cc: stable@vger.kernel.org
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
and netfilter trees.
Current release - regressions:
- mac80211: fix starting aggregation sessions on mesh interfaces
Current release - new code bugs:
- sctp: send pmtu probe only if packet loss in Search Complete state
- bnxt_en: add missing periodic PHC overflow check
- devlink: fix phys_port_name of virtual port and merge error
- hns3: change the method of obtaining default ptp cycle
- can: mcba_usb_start(): add missing urb->transfer_dma initialization
Previous releases - regressions:
- set true network header for ECN decapsulation
- mlx5e: RX, avoid possible data corruption w/ relaxed ordering and LRO
- phy: re-add check for PHY_BRCM_DIS_TXCRXC_NOENRGY on the BCM54811 PHY
- sctp: fix return value check in __sctp_rcv_asconf_lookup
Previous releases - always broken:
- bpf:
- more spectre corner case fixes, introduce a BPF nospec
instruction for mitigating Spectre v4
- fix OOB read when printing XDP link fdinfo
- sockmap: fix cleanup related races
- mac80211: fix enabling 4-address mode on a sta vif after assoc
- can:
- raw: raw_setsockopt(): fix raw_rcv panic for sock UAF
- j1939: j1939_session_deactivate(): clarify lifetime of
session object, avoid UAF
- fix number of identical memory leaks in USB drivers
- tipc:
- do not blindly write skb_shinfo frags when doing decryption
- fix sleeping in tipc accept routine
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Merge tag 'net-5.14-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Pull networking fixes from Jakub Kicinski:
"Networking fixes for 5.14-rc4, including fixes from bpf, can, WiFi
(mac80211) and netfilter trees.
Current release - regressions:
- mac80211: fix starting aggregation sessions on mesh interfaces
Current release - new code bugs:
- sctp: send pmtu probe only if packet loss in Search Complete state
- bnxt_en: add missing periodic PHC overflow check
- devlink: fix phys_port_name of virtual port and merge error
- hns3: change the method of obtaining default ptp cycle
- can: mcba_usb_start(): add missing urb->transfer_dma initialization
Previous releases - regressions:
- set true network header for ECN decapsulation
- mlx5e: RX, avoid possible data corruption w/ relaxed ordering and
LRO
- phy: re-add check for PHY_BRCM_DIS_TXCRXC_NOENRGY on the BCM54811
PHY
- sctp: fix return value check in __sctp_rcv_asconf_lookup
Previous releases - always broken:
- bpf:
- more spectre corner case fixes, introduce a BPF nospec
instruction for mitigating Spectre v4
- fix OOB read when printing XDP link fdinfo
- sockmap: fix cleanup related races
- mac80211: fix enabling 4-address mode on a sta vif after assoc
- can:
- raw: raw_setsockopt(): fix raw_rcv panic for sock UAF
- j1939: j1939_session_deactivate(): clarify lifetime of session
object, avoid UAF
- fix number of identical memory leaks in USB drivers
- tipc:
- do not blindly write skb_shinfo frags when doing decryption
- fix sleeping in tipc accept routine"
* tag 'net-5.14-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (91 commits)
gve: Update MAINTAINERS list
can: esd_usb2: fix memory leak
can: ems_usb: fix memory leak
can: usb_8dev: fix memory leak
can: mcba_usb_start(): add missing urb->transfer_dma initialization
can: hi311x: fix a signedness bug in hi3110_cmd()
MAINTAINERS: add Yasushi SHOJI as reviewer for the Microchip CAN BUS Analyzer Tool driver
bpf: Fix leakage due to insufficient speculative store bypass mitigation
bpf: Introduce BPF nospec instruction for mitigating Spectre v4
sis900: Fix missing pci_disable_device() in probe and remove
net: let flow have same hash in two directions
nfc: nfcsim: fix use after free during module unload
tulip: windbond-840: Fix missing pci_disable_device() in probe and remove
sctp: fix return value check in __sctp_rcv_asconf_lookup
nfc: s3fwrn5: fix undefined parameter values in dev_err()
net/mlx5: Fix mlx5_vport_tbl_attr chain from u16 to u32
net/mlx5e: Fix nullptr in mlx5e_hairpin_get_mdev()
net/mlx5: Unload device upon firmware fatal error
net/mlx5e: Fix page allocation failure for ptp-RQ over SF
net/mlx5e: Fix page allocation failure for trap-RQ over SF
...
zstd decompression uses __builtin_clz() which fails back to __clzdi2()
when the kernel is built for older hardware like z900. This leads to
build failures like the following:
s390x-11.1.0-ld: /devel/src/kernel/arch/s390/boot/compressed/../../../../lib/zstd/bitstream.h:148: undefined reference to `__clzdi2'
Fix that by optionally including lib/clz_ctz.c into the decompressor.
Reported-by: kernel test robot <lkp@intel.com>
Fixes: 7b034d9c1b ("s390/boot: add zstd support")
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Link: https://lore.kernel.org/r/patch-1.thread-f0f589.git-f0f58936888f.your-ad-here.call-01627564869-ext-2765@work.hours
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
- Fix MTE shared page detection
- Enable selftest's use of PMU registers when asked to
s390:
- restore 5.13 debugfs names
x86:
- fix sizes for vcpu-id indexed arrays
- fixes for AMD virtualized LAPIC (AVIC)
- other small bugfixes
Generic:
- access tracking performance test
- dirty_log_perf_test command line parsing fix
- Fix selftest use of obsolete pthread_yield() in favour of sched_yield()
- use cpu_relax when halt polling
- fixed missing KVM_CLEAR_DIRTY_LOG compat ioctl
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull kvm fixes from Paolo Bonzini:
"ARM:
- Fix MTE shared page detection
- Enable selftest's use of PMU registers when asked to
s390:
- restore 5.13 debugfs names
x86:
- fix sizes for vcpu-id indexed arrays
- fixes for AMD virtualized LAPIC (AVIC)
- other small bugfixes
Generic:
- access tracking performance test
- dirty_log_perf_test command line parsing fix
- Fix selftest use of obsolete pthread_yield() in favour of
sched_yield()
- use cpu_relax when halt polling
- fixed missing KVM_CLEAR_DIRTY_LOG compat ioctl"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: add missing compat KVM_CLEAR_DIRTY_LOG
KVM: use cpu_relax when halt polling
KVM: SVM: use vmcb01 in svm_refresh_apicv_exec_ctrl
KVM: SVM: tweak warning about enabled AVIC on nested entry
KVM: SVM: svm_set_vintr don't warn if AVIC is active but is about to be deactivated
KVM: s390: restore old debugfs names
KVM: SVM: delay svm_vcpu_init_msrpm after svm->vmcb is initialized
KVM: selftests: Introduce access_tracking_perf_test
KVM: selftests: Fix missing break in dirty_log_perf_test arg parsing
x86/kvm: fix vcpu-id indexed array sizes
KVM: x86: Check the right feature bit for MSR_KVM_ASYNC_PF_ACK access
docs: virt: kvm: api.rst: replace some characters
KVM: Documentation: Fix KVM_CAP_ENFORCE_PV_FEATURE_CPUID name
KVM: nSVM: Swap the parameter order for svm_copy_vmrun_state()/svm_copy_vmloadsave_state()
KVM: nSVM: Rename nested_svm_vmloadsave() to svm_copy_vmloadsave_state()
KVM: arm64: selftests: get-reg-list: actually enable pmu regs in pmu sublist
KVM: selftests: change pthread_yield to sched_yield
KVM: arm64: Fix detection of shared VMAs on guest fault
Daniel Borkmann says:
====================
pull-request: bpf 2021-07-29
The following pull-request contains BPF updates for your *net* tree.
We've added 9 non-merge commits during the last 14 day(s) which contain
a total of 20 files changed, 446 insertions(+), 138 deletions(-).
The main changes are:
1) Fix UBSAN out-of-bounds splat for showing XDP link fdinfo, from Lorenz Bauer.
2) Fix insufficient Spectre v4 mitigation in BPF runtime, from Daniel Borkmann,
Piotr Krysiuk and Benedict Schlueter.
3) Batch of fixes for BPF sockmap found under stress testing, from John Fastabend.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
In case of JITs, each of the JIT backends compiles the BPF nospec instruction
/either/ to a machine instruction which emits a speculation barrier /or/ to
/no/ machine instruction in case the underlying architecture is not affected
by Speculative Store Bypass or has different mitigations in place already.
This covers both x86 and (implicitly) arm64: In case of x86, we use 'lfence'
instruction for mitigation. In case of arm64, we rely on the firmware mitigation
as controlled via the ssbd kernel parameter. Whenever the mitigation is enabled,
it works for all of the kernel code with no need to provide any additional
instructions here (hence only comment in arm64 JIT). Other archs can follow
as needed. The BPF nospec instruction is specifically targeting Spectre v4
since i) we don't use a serialization barrier for the Spectre v1 case, and
ii) mitigation instructions for v1 and v4 might be different on some archs.
The BPF nospec is required for a future commit, where the BPF verifier does
annotate intermediate BPF programs with speculation barriers.
Co-developed-by: Piotr Krysiuk <piotras@gmail.com>
Co-developed-by: Benedict Schlueter <benedict.schlueter@rub.de>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Piotr Krysiuk <piotras@gmail.com>
Signed-off-by: Benedict Schlueter <benedict.schlueter@rub.de>
Acked-by: Alexei Starovoitov <ast@kernel.org>
commit bc9e9e672d ("KVM: debugfs: Reuse binary stats descriptors")
did replace the old definitions with the binary ones. While doing that
it missed that some files are names different than the counters. This
is especially important for kvm_stat which does have special handling
for counters named instruction_*.
Fixes: commit bc9e9e672d ("KVM: debugfs: Reuse binary stats descriptors")
CC: Jing Zhang <jingzhangos@google.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Message-Id: <20210726150108.5603-1-borntraeger@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Pull networking fixes from David Miller:
1) Fix type of bind option flag in af_xdp, from Baruch Siach.
2) Fix use after free in bpf_xdp_link_release(), from Xuan Zhao.
3) PM refcnt imbakance in r8152, from Takashi Iwai.
4) Sign extension ug in liquidio, from Colin Ian King.
5) Mising range check in s390 bpf jit, from Colin Ian King.
6) Uninit value in caif_seqpkt_sendmsg(), from Ziyong Xuan.
7) Fix skb page recycling race, from Ilias Apalodimas.
8) Fix memory leak in tcindex_partial_destroy_work, from Pave Skripkin.
9) netrom timer sk refcnt issues, from Nguyen Dinh Phi.
10) Fix data races aroun tcp's tfo_active_disable_stamp, from Eric
Dumazet.
11) act_skbmod should only operate on ethernet packets, from Peilin Ye.
12) Fix slab out-of-bpunds in fib6_nh_flush_exceptions(),, from Psolo
Abeni.
13) Fix sparx5 dependencies, from Yajun Deng.
* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (74 commits)
dpaa2-switch: seed the buffer pool after allocating the swp
net: sched: cls_api: Fix the the wrong parameter
net: sparx5: fix unmet dependencies warning
net: dsa: tag_ksz: dont let the hardware process the layer 4 checksum
net: dsa: ensure linearized SKBs in case of tail taggers
ravb: Remove extra TAB
ravb: Fix a typo in comment
net: dsa: sja1105: make VID 4095 a bridge VLAN too
tcp: disable TFO blackhole logic by default
sctp: do not update transport pathmtu if SPP_PMTUD_ENABLE is not set
net: ixp46x: fix ptp build failure
ibmvnic: Remove the proper scrq flush
selftests: net: add ESP-in-UDP PMTU test
udp: check encap socket in __udp_lib_err
sctp: update active_key for asoc when old key is being replaced
r8169: Avoid duplicate sysfs entry creation error
ixgbe: Fix packet corruption due to missing DMA sync
Revert "qed: fix possible unpaired spin_{un}lock_bh in _qed_mcp_cmd_and_union()"
ipv6: fix another slab-out-of-bounds in fib6_nh_flush_exceptions
fsl/fman: Add fibre support
...
The DMA code section of the decompressor must be compiled with expolines
if Spectre V2 mitigation has been enabled for the decompressed kernel.
This is required because although the decompressor's image contains
the DMA code section, it is handed over to the decompressed kernel for use.
Because the DMA code is already slow w/o expolines, use expolines always
regardless whether the decompressed kernel is using them or not. This
simplifies the DMA code by dropping the conditional compilation of
expolines.
Fixes: bf72630130 ("s390: use proper expoline sections for .dma code")
Cc: <stable@vger.kernel.org> # 5.2
Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Andrii Nakryiko says:
====================
pull-request: bpf 2021-07-15
The following pull-request contains BPF updates for your *net* tree.
We've added 9 non-merge commits during the last 5 day(s) which contain
a total of 9 files changed, 37 insertions(+), 15 deletions(-).
The main changes are:
1) Fix NULL pointer dereference in BPF_TEST_RUN for BPF_XDP_DEVMAP and
BPF_XDP_CPUMAP programs, from Xuan Zhuo.
2) Fix use-after-free of net_device in XDP bpf_link, from Xuan Zhuo.
3) Follow-up fix to subprog poke descriptor use-after-free problem, from
Daniel Borkmann and John Fastabend.
4) Fix out-of-range array access in s390 BPF JIT backend, from Colin Ian King.
5) Fix memory leak in BPF sockmap, from John Fastabend.
6) Fix for sockmap to prevent proc stats reporting bug, from John Fastabend
and Jakub Sitnicki.
7) Fix NULL pointer dereference in bpftool, from Tobias Klauser.
8) AF_XDP documentation fixes, from Baruch Siach.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently array jit->seen_reg[r1] is being accessed before the range
checking of index r1. The range changing on r1 should be performed
first since it will avoid any potential out-of-range accesses on the
array seen_reg[] and also it is more optimal to perform checks on r1
before fetching data from the array. Fix this by swapping the order
of the checks before the array access.
Fixes: 0546231057 ("s390/bpf: Add s390x eBPF JIT compiler backend")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Ilya Leoshkevich <iii@linux.ibm.com>
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/bpf/20210715125712.24690-1-colin.king@canonical.com
doing make install on an Ubuntu that is installed on an LVM will fail to
boot. Turns out that defconfig misses 2 device mapper related configs
for the Ubuntu initramfs.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Steffen Maier <maier@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
This fixes a permanent rebuild of the 32 bit vdso. The RPM build process
was first calling 'make bzImage' and 'make modules' as a second step.
This caused a recompilation of vdso32.so, which in turn also changed
the build-id of vmlinux.
Fixes: 779df22487 ("s390/vdso: add minimal compat vdso")
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
- Increase the -falign-functions alignment for the debug option.
- Remove ugly libelf checks from the top Makefile.
- Make the silent build (-s) more silent.
- Re-compile the kernel if KBUILD_BUILD_TIMESTAMP is specified.
- Various script cleanups
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Merge tag 'kbuild-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
- Increase the -falign-functions alignment for the debug option.
- Remove ugly libelf checks from the top Makefile.
- Make the silent build (-s) more silent.
- Re-compile the kernel if KBUILD_BUILD_TIMESTAMP is specified.
- Various script cleanups
* tag 'kbuild-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (27 commits)
scripts: add generic syscallnr.sh
scripts: check duplicated syscall number in syscall table
sparc: syscalls: use pattern rules to generate syscall headers
parisc: syscalls: use pattern rules to generate syscall headers
nds32: add arch/nds32/boot/.gitignore
kbuild: mkcompile_h: consider timestamp if KBUILD_BUILD_TIMESTAMP is set
kbuild: modpost: Explicitly warn about unprototyped symbols
kbuild: remove trailing slashes from $(KBUILD_EXTMOD)
kconfig.h: explain IS_MODULE(), IS_ENABLED()
kconfig: constify long_opts
scripts/setlocalversion: simplify the short version part
scripts/setlocalversion: factor out 12-chars hash construction
scripts/setlocalversion: add more comments to -dirty flag detection
scripts/setlocalversion: remove workaround for old make-kpkg
scripts/setlocalversion: remove mercurial, svn and git-svn supports
kbuild: clean up ${quiet} checks in shell scripts
kbuild: sink stdout from cmd for silent build
init: use $(call cmd,) for generating include/generated/compile.h
kbuild: merge scripts/mkmakefile to top Makefile
sh: move core-y in arch/sh/Makefile to arch/sh/Kbuild
...
- Fix preempt_count initialization.
- Rework call_on_stack() macro to add proper type handling and avoid
possible register corruption.
- More error prone "register asm" removal and fixes.
- Fix syscall restarting when multiple signals are coming in. This adds
minimalistic trampolines to vdso so we can return from signal without
using the stack which requires pgm check handler hacks when NX is
enabled.
- Remove HAVE_IRQ_EXIT_ON_IRQ_STACK since this is no longer true after
switch to generic entry.
- Fix protected virtualization secure storage access exception handling.
- Make machine check C handler always enter with DAT enabled and move
register validation to C code.
- Fix tinyconfig boot problem by avoiding MONITOR CALL without CONFIG_BUG.
- Increase asm symbols alignment to 16 to make it consistent with
compilers.
- Enable concurrent access to the CPU Measurement Counter Facility.
- Add support for dynamic AP bus size limit and rework ap_dqap to deal
with messages greater than recv buffer.
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Merge tag 's390-5.14-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull more s390 updates from Vasily Gorbik:
- Fix preempt_count initialization.
- Rework call_on_stack() macro to add proper type handling and avoid
possible register corruption.
- More error prone "register asm" removal and fixes.
- Fix syscall restarting when multiple signals are coming in. This adds
minimalistic trampolines to vdso so we can return from signal without
using the stack which requires pgm check handler hacks when NX is
enabled.
- Remove HAVE_IRQ_EXIT_ON_IRQ_STACK since this is no longer true after
switch to generic entry.
- Fix protected virtualization secure storage access exception
handling.
- Make machine check C handler always enter with DAT enabled and move
register validation to C code.
- Fix tinyconfig boot problem by avoiding MONITOR CALL without
CONFIG_BUG.
- Increase asm symbols alignment to 16 to make it consistent with
compilers.
- Enable concurrent access to the CPU Measurement Counter Facility.
- Add support for dynamic AP bus size limit and rework ap_dqap to deal
with messages greater than recv buffer.
* tag 's390-5.14-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (41 commits)
s390: preempt: Fix preempt_count initialization
s390/linkage: increase asm symbols alignment to 16
s390: rename CALL_ON_STACK_NORETURN() to call_on_stack_noreturn()
s390: add type checking to CALL_ON_STACK_NORETURN() macro
s390: remove old CALL_ON_STACK() macro
s390/softirq: use call_on_stack() macro
s390/lib: use call_on_stack() macro
s390/smp: use call_on_stack() macro
s390/kexec: use call_on_stack() macro
s390/irq: use call_on_stack() macro
s390/mm: use call_on_stack() macro
s390: introduce proper type handling call_on_stack() macro
s390/irq: simplify on_async_stack()
s390/irq: inline do_softirq_own_stack()
s390/irq: simplify do_softirq_own_stack()
s390/ap: get rid of register asm in ap_dqap()
s390: rename PIF_SYSCALL_RESTART to PIF_EXECVE_PGSTE_RESTART
s390: move restart of execve() syscall
s390/signal: remove sigreturn on stack
s390/signal: switch to using vdso for sigreturn and syscall restart
...
S390's init_idle_preempt_count(p, cpu) doesn't actually let us initialize the
preempt_count of the requested CPU's idle task: it unconditionally writes
to the current CPU's. This clearly conflicts with idle_threads_init(),
which intends to initialize *all* the idle tasks, including their
preempt_count (or their CPU's, if the arch uses a per-CPU preempt_count).
Unfortunately, it seems the way s390 does things doesn't let us initialize
every possible CPU's preempt_count early on, as the pages where this
resides are only allocated when a CPU is brought up and are freed when it
is brought down.
Let the arch-specific code set a CPU's preempt_count when its lowcore is
allocated, and turn init_idle_preempt_count() into an empty stub.
Fixes: f1a0a376ca ("sched/core: Initialize the idle task with preemption disabled")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Link: https://lore.kernel.org/r/20210707163338.1623014-1-valentin.schneider@arm.com
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Both clang and gcc (for -march=z13 and later) align functions to 16
bytes at -O2 to benefit branch prediction.
Make asm symbols alignment consistent with that.
This also benefits potential ftrace code patching, which is currently
able to patch 8 aligned bytes at once.
With defconfig this currently increases .text size by 4104 bytes.
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Lower case matches the call_on_stack() macro and is easier to read.
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Make sure the to be called function takes no arguments (and returns void).
Otherwise usage of CALL_ON_STACK_NORETURN() would generate broken code.
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
The existing CALL_ON_STACK() macro allows for subtle bugs:
- There is no type checking of the function that is being called. That
is: missing or too many arguments do not cause any compile error or
warning. The same is true if the return type of the called function
changes. This can lead to quite random bugs.
- Sign and zero extension of arguments is missing. Given that the s390
C ABI requires that the caller of a function performs proper sign
and zero extension this can also lead to subtle bugs.
- If arguments to the CALL_ON_STACK() macros contain functions calls
register corruption can happen due to register asm constructs being
used.
Therefore introduce a new call_on_stack() macro which is supposed to
fix all these problems.
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Make on_async_stack() a bit more readable, even though as usual it
depends if one considers "!!!" readable or not.
At least the new construct to check if the async stack is in use or
not is a bit shorter and generates slightly better code.
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Move do_softirq_own_stack() to proper header file so it can be
inlined; saving a few cycles.
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
do_softirq_own_stack() is always called from task context and
therefore it is not necessary to check if the async stack is
currently used.
Remove the check and directly switch to async stack.
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
This is the second part of the cleanup for the header file ap.h
to remove the register asm statements. This patch deals with
the inline ap_dqap() function where within the assembler code
an odd register of an register pair is to be addressed.
[hca@linux.ibm.com: this intentionally breaks compilation with any
clang compilers prior to llvm-project commit 458eac257377 ("[SystemZ]
Support the 'N' code for the odd register in inline-asm.").
This is hopefully the last clang kernel compile breakage caused by
incompatibilities between gcc and clang.]
Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
PIF_SYSCALL_RESTART is now only used to restart execve when loading
PGSTE binaries. Rename the flag to reflect that, and avoid people
thinking that this bit has anything to do with generic syscall
restarting.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
On s390, execve might have to be restarted for PGSTE binaries
like kvm. In the past this was done via the PIF_SYSCALL_RESTART
bit. However, with the recent changes, syscalls are now restarted
differently. Now that execve() is the only call that might get
restarted via PIF_SYSCALL_RESTART, move the loop to do_syscall().
This also has the advantage that the restart is no longer visible
to userspace.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
{rt_}sigreturn is now called from the vdso, so we no longer
need the svc on the stack, and therefore no hack to support that
mechanism on machines with non-executable stack.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
with generic entry, there's a bug when it comes to restarting of signals.
The failing sequence is:
a) a signal is coming in, and no handler is registered, so the lower
part of arch_do_signal_or_restart() in arch/s390/kernel/signal.c
sets PIF_SYSCALL_RESTART.
b) a second signal gets pending while the kernel is still in the exit
loop, and for that one, a handler exists.
c) The first part of arch_do_signal_or_restart() is called. That part
calls handle_signal(), which sets up stack + registers for handling
the signal.
d) __do_syscall() in arch/s390/kernel/syscall.c checks for
PIF_SYSCALL_RESTART right before leaving to userspace. If it is set,
it restart's the syscall. However, the registers are already setup
for handling a signal from c). The syscall is now restarted with the
wrong arguments.
Change the code to:
- use vdso for syscall_restart() instead of PIF_SYSCALL_RESTART because
we cannot rewind and go back to userspace on s390 because the system call
number might be encoded in the svc instruction.
- for all other syscalls we rewind the PSW and return to userspace.
Cc: <stable@kernel.org> # v5.12+ d57778feb9: s390/vdso: always enable vdso
Cc: <stable@kernel.org> # v5.12+ 686341f254: s390/vdso64: add sigreturn,rt_sigreturn and restart_syscall
Cc: <stable@kernel.org> # v5.12+ 43e1f76b0b: s390/vdso: rename VDSO64_LBASE to VDSO_LBASE
Cc: <stable@kernel.org> # v5.12+ 779df22487: s390/vdso: add minimal compat vdso
Cc: <stable@kernel.org> # v5.12+
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Add a small vdso for 31 bit compat application that provides
trampolines for calls to sigreturn,rt_sigreturn,syscall_restart.
This is requird for moving these syscalls away from the signal
frame to the vdso. Note that this patch effectively disables
CONFIG_COMPAT when using clang to compile the kernel. clang
doesn't support 31 bit mode.
We want to redirect sigreturn and restart_syscall to the vdso. However,
the kernel cannot parse the ELF vdso file, so we need to generate header
files which contain the offsets of the syscall instructions in the vdso
page.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Will be used by both vdso32 and vdso64, so change the name.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Add minimalistic trampolines to vdso64 so we can return from signal
without using the stack which requires pgm check handler hacks when
NX is enabled.
restart_syscall will be called from vdso to work around the architectural
limitation that the syscall number might be encoded in the svc instruction,
and therefore can not be changed.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
With the upcoming move of the svc sigreturn instruction from
the signal frame to vdso we need to have vdso always enabled.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Using register asm statements has been proven to be very error prone,
especially when using code instrumentation where gcc may add function
calls, which clobbers register contents in an unexpected way.
Therefore get rid of register asm statements in ap code. There are also
potential bugs, depending on inline decisions of the compiler.
E.g. for:
static inline struct ap_queue_status ap_tapq(ap_qid_t qid, unsigned long *info)
{
register unsigned long reg0 asm ("0") = qid;
register struct ap_queue_status reg1 asm ("1");
register unsigned long reg2 asm ("2");
asm volatile(".long 0xb2af0000" /* PQAP(TAPQ) */
: "=d" (reg1), "=d" (reg2)
: "d" (reg0)
: "cc");
if (info)
*info = reg2;
return reg1;
}
In case of KCOV the "if (info)" line could cause a generated function
call, which could clobber the contents of both reg2, and reg1.
Similar can happen in case of KASAN for the "*info = reg2" line.
Even though compilers will likely inline the function and optimize
things away, this is not guaranteed.
To get rid of this bug class, simply get rid of register asm constructs.
Note: The inline function ap_dqap() will be handled in a
separate patch because this one requires an addressing of the
odd register of a register pair (which is done with %N[xxx] in
the assembler code) and that's currently not supported by clang.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
