Will Deacon [Thu, 13 Feb 2020 12:06:26 +0000 (12:06 +0000)]
arm64: ptrace: Override SPSR.SS when single-stepping is enabled
Luis reports that, when reverse debugging with GDB, single-step does not
function as expected on arm64:
| I've noticed, under very specific conditions, that a PTRACE_SINGLESTEP
| request by GDB won't execute the underlying instruction. As a consequence,
| the PC doesn't move, but we return a SIGTRAP just like we would for a
| regular successful PTRACE_SINGLESTEP request.
The underlying problem is that when the CPU register state is restored
as part of a reverse step, the SPSR.SS bit is cleared and so the hardware
single-step state can transition to the "active-pending" state, causing
an unexpected step exception to be taken immediately if a step operation
is attempted.
In hindsight, we probably shouldn't have exposed SPSR.SS in the pstate
accessible by the GPR regset, but it's a bit late for that now. Instead,
simply prevent userspace from configuring the bit to a value which is
inconsistent with the TIF_SINGLESTEP state for the task being traced.
Cc: <stable@vger.kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Keno Fischer <keno@juliacomputing.com> Link: https://lore.kernel.org/r/1eed6d69-d53d-9657-1fc9-c089be07f98c@linaro.org Reported-by: Luis Machado <luis.machado@linaro.org> Tested-by: Luis Machado <luis.machado@linaro.org> Signed-off-by: Will Deacon <will@kernel.org>
Will Deacon [Thu, 2 Jul 2020 20:16:20 +0000 (21:16 +0100)]
arm64: ptrace: Consistently use pseudo-singlestep exceptions
Although the arm64 single-step state machine can be fast-forwarded in
cases where we wish to generate a SIGTRAP without actually executing an
instruction, this has two major limitations outside of simply skipping
an instruction due to emulation.
1. Stepping out of a ptrace signal stop into a signal handler where
SIGTRAP is blocked. Fast-forwarding the stepping state machine in
this case will result in a forced SIGTRAP, with the handler reset to
SIG_DFL.
2. The hardware implicitly fast-forwards the state machine when executing
an SVC instruction for issuing a system call. This can interact badly
with subsequent ptrace stops signalled during the execution of the
system call (e.g. SYSCALL_EXIT or seccomp traps), as they may corrupt
the stepping state by updating the PSTATE for the tracee.
Resolve both of these issues by injecting a pseudo-singlestep exception
on entry to a signal handler and also on return to userspace following a
system call.
Cc: <stable@vger.kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Tested-by: Luis Machado <luis.machado@linaro.org> Reported-by: Keno Fischer <keno@juliacomputing.com> Signed-off-by: Will Deacon <will@kernel.org>
To solve the above issue, current module should be registered to kernel,
so that try_module_get() can be invoked when perf sampling starts. This
adds the reference counting of module and could prevent users from removing
modules during sampling.
Will Deacon [Thu, 9 Jul 2020 20:48:41 +0000 (21:48 +0100)]
efi/libstub/arm64: Retain 2MB kernel Image alignment if !KASLR
Since commit 82046702e288 ("efi/libstub/arm64: Replace 'preferred' offset
with alignment check"), loading a relocatable arm64 kernel at a physical
address which is not 2MB aligned and subsequently booting with EFI will
leave the Image in-place, relying on the kernel to relocate itself early
during boot. In conjunction with commit dd4bc6076587 ("arm64: warn on
incorrect placement of the kernel by the bootloader"), which enables
CONFIG_RELOCATABLE by default, this effectively means that entering an
arm64 kernel loaded at an alignment smaller than 2MB with EFI (e.g. using
QEMU) will result in silent relocation at runtime.
Unfortunately, this has a subtle but confusing affect for developers
trying to inspect the PC value during a crash and comparing it to the
symbol addresses in vmlinux using tools such as 'nm' or 'addr2line';
all text addresses will be displaced by a sub-2MB offset, resulting in
the wrong symbol being identified in many cases. Passing "nokaslr" on
the command line or disabling "CONFIG_RANDOMIZE_BASE" does not help,
since the EFI stub only copies the kernel Image to a 2MB boundary if it
is not relocatable.
Adjust the EFI stub for arm64 so that the minimum Image alignment is 2MB
unless KASLR is in use.
Cc: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Marc Zyngier <maz@kernel.org> Cc: David Brazdil <dbrazdil@google.com> Acked-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Will Deacon <will@kernel.org>
arm64/alternatives: don't patch up internal branches
Commit f7b93d42945c ("arm64/alternatives: use subsections for replacement
sequences") moved the alternatives replacement sequences into subsections,
in order to keep the as close as possible to the code that they replace.
Unfortunately, this broke the logic in branch_insn_requires_update,
which assumed that any branch into kernel executable code was a branch
that required updating, which is no longer the case now that the code
sequences that are patched in are in the same section as the patch site
itself.
So the only way to discriminate branches that require updating and ones
that don't is to check whether the branch targets the replacement sequence
itself, and so we can drop the call to kernel_text_address() entirely.
Fixes: f7b93d42945c ("arm64/alternatives: use subsections for replacement sequences") Reported-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Tested-by: Alexandru Elisei <alexandru.elisei@arm.com> Link: https://lore.kernel.org/r/20200709125953.30918-1-ardb@kernel.org Signed-off-by: Will Deacon <will@kernel.org>
When the erratum_1463225 array was introduced a sentinel at the end was
missing thus causing a KASAN: global-out-of-bounds in
is_affected_midr_range_list on arm64 error.
arm64: Documentation: Fix broken table in generated HTML
cpu-feature-registers.rst is missing a new line before a couple
of tables listing the visible fields, causing broken tables in
the HTML documentation generated by "make htmldocs". Fix this
by adding the missing new line.
Reported-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Link: https://lore.kernel.org/r/20200707143152.154541-1-suzuki.poulose@arm.com Signed-off-by: Will Deacon <will@kernel.org>
After entering kdb due to breakpoint, when we execute 'ss' or 'go' (will
delay installing breakpoints, do single-step first), it won't work
correctly, and it will enter kdb due to oops.
It's because the reason gotten in kdb_stub() is not as expected, and it
seems that the ex_vector for single-step should be 0, like what arch
powerpc/sh/parisc has implemented.
Before the patch:
Entering kdb (current=0xffff8000119e2dc0, pid 0) on processor 0 due to Keyboard Entry
[0]kdb> bp printk
Instruction(i) BP #0 at 0xffff8000101486cc (printk)
is enabled addr at ffff8000101486cc, hardtype=0 installed=0
[0]kdb> g
/ # echo h > /proc/sysrq-trigger
Entering kdb (current=0xffff0000fa878040, pid 266) on processor 3 due to Breakpoint @ 0xffff8000101486cc
[3]kdb> ss
After the patch:
Entering kdb (current=0xffff8000119e2dc0, pid 0) on processor 0 due to Keyboard Entry
[0]kdb> bp printk
Instruction(i) BP #0 at 0xffff8000101486cc (printk)
is enabled addr at ffff8000101486cc, hardtype=0 installed=0
[0]kdb> g
/ # echo h > /proc/sysrq-trigger
Entering kdb (current=0xffff0000fa852bc0, pid 268) on processor 0 due to Breakpoint @ 0xffff8000101486cc
[0]kdb> g
Entering kdb (current=0xffff0000fa852bc0, pid 268) on processor 0 due to Breakpoint @ 0xffff8000101486cc
[0]kdb> ss
Entering kdb (current=0xffff0000fa852bc0, pid 268) on processor 0 due to SS trap @ 0xffff800010082ab8
[0]kdb>
Fixes: 44679a4f142b ("arm64: KGDB: Add step debugging support") Signed-off-by: Wei Li <liwei391@huawei.com> Tested-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20200509214159.19680-2-liwei391@huawei.com Signed-off-by: Will Deacon <will@kernel.org>
Will Deacon [Wed, 8 Jul 2020 21:10:01 +0000 (22:10 +0100)]
arm64: entry: Tidy up block comments and label numbers
Continually butchering our entry code with CPU errata workarounds has
led to it looking a little scruffy. Consistently used /* */ comment
style for multi-line block comments and ensure that small numeric labels
use consecutive integers.
No functional change, but the state of things was irritating.
Marc Zyngier [Mon, 6 Jul 2020 16:38:02 +0000 (17:38 +0100)]
arm64: Rework ARM_ERRATUM_1414080 handling
The current handling of erratum 1414080 has the side effect that
cntkctl_el1 can get changed for both 32 and 64bit tasks.
This isn't a problem so far, but if we ever need to mitigate another
of these errata on the 64bit side, we'd better keep the messing with
cntkctl_el1 local to 32bit tasks.
For that, make sure that on entering the kernel from a 32bit tasks,
userspace access to cntvct gets enabled, and disabled returning to
userspace, while it never gets changed for 64bit tasks.
Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Link: https://lore.kernel.org/r/20200706163802.1836732-5-maz@kernel.org
[will: removed branch instructions per Mark's review comments] Signed-off-by: Will Deacon <will@kernel.org>
Marc Zyngier [Mon, 6 Jul 2020 16:38:01 +0000 (17:38 +0100)]
arm64: arch_timer: Disable the compat vdso for cores affected by ARM64_WORKAROUND_1418040
ARM64_WORKAROUND_1418040 requires that AArch32 EL0 accesses to
the virtual counter register are trapped and emulated by the kernel.
This makes the vdso pretty pointless, and in some cases livelock
prone.
Provide a workaround entry that limits the vdso to 64bit tasks.
Marc Zyngier [Mon, 6 Jul 2020 16:37:59 +0000 (17:37 +0100)]
arm64: Introduce a way to disable the 32bit vdso
We have a class of errata (grouped under the ARM64_WORKAROUND_1418040
banner) that force the trapping of counter access from 32bit EL0.
We would normally disable the whole vdso for such defect, except that
it would disable it for 64bit userspace as well, which is a shame.
Instead, add a new vdso_clock_mode, which signals that the vdso
isn't usable for compat tasks. This gets checked in the new
vdso_clocksource_ok() helper, now provided for the 32bit vdso.
Gavin Shan [Tue, 30 Jun 2020 07:52:27 +0000 (17:52 +1000)]
drivers/firmware/psci: Fix memory leakage in alloc_init_cpu_groups()
The CPU mask (@tmp) should be released on failing to allocate
@cpu_groups or any of its elements. Otherwise, it leads to memory
leakage because the CPU mask variable is dynamically allocated
when CONFIG_CPUMASK_OFFSTACK is enabled.
Will Deacon [Wed, 8 Jul 2020 16:25:46 +0000 (17:25 +0100)]
KVM: arm64: Fix definition of PAGE_HYP_DEVICE
PAGE_HYP_DEVICE is intended to encode attribute bits for an EL2 stage-1
pte mapping a device. Unfortunately, it includes PROT_DEVICE_nGnRE which
encodes attributes for EL1 stage-1 mappings such as UXN and nG, which are
RES0 for EL2, and DBM which is meaningless as TCR_EL2.HD is not set.
Fix the definition of PAGE_HYP_DEVICE so that it doesn't set RES0 bits
at EL2.
Acked-by: Marc Zyngier <maz@kernel.org> Cc: Marc Zyngier <maz@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: James Morse <james.morse@arm.com> Cc: <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20200708162546.26176-1-will@kernel.org Signed-off-by: Will Deacon <will@kernel.org>
arm64: Add KRYO4XX silver CPU cores to erratum list 1530923 and 1024718
KRYO4XX silver/LITTLE CPU cores with revision r1p0 are affected by
erratum 1530923 and 1024718, so add them to the respective list.
The variant and revision bits are implementation defined and are
different from the their Cortex CPU counterparts on which they are
based on, i.e., r1p0 is equivalent to rdpe.
arm64: Add KRYO4XX gold CPU cores to erratum list 1463225 and 1418040
KRYO4XX gold/big CPU core revisions r0p0 to r3p1 are affected by
erratum 1463225 and 1418040, so add them to the respective list.
The variant and revision bits are implementation defined and are
different from the their Cortex CPU counterparts on which they are
based on, i.e., (r0p0 to r3p1) is equivalent to (rcpe to rfpf).
Add MIDR value for KRYO4XX gold/big CPU cores which are
used in Qualcomm Technologies, Inc. SoCs. This will be
used to identify and apply erratum which are applicable
for these CPU cores.
Ard Biesheuvel [Tue, 30 Jun 2020 08:19:21 +0000 (10:19 +0200)]
arm64/alternatives: use subsections for replacement sequences
When building very large kernels, the logic that emits replacement
sequences for alternatives fails when relative branches are present
in the code that is emitted into the .altinstr_replacement section
and patched in at the original site and fixed up. The reason is that
the linker will insert veneers if relative branches go out of range,
and due to the relative distance of the .altinstr_replacement from
the .text section where its branch targets usually live, veneers
may be emitted at the end of the .altinstr_replacement section, with
the relative branches in the sequence pointed at the veneers instead
of the actual target.
The alternatives patching logic will attempt to fix up the branch to
point to its original target, which will be the veneer in this case,
but given that the patch site is likely to be far away as well, it
will be out of range and so patching will fail. There are other cases
where these veneers are problematic, e.g., when the target of the
branch is in .text while the patch site is in .init.text, in which
case putting the replacement sequence inside .text may not help either.
So let's use subsections to emit the replacement code as closely as
possible to the patch site, to ensure that veneers are only likely to
be emitted if they are required at the patch site as well, in which
case they will be in range for the replacement sequence both before
and after it is transported to the patch site.
This will prevent alternative sequences in non-init code from being
released from memory after boot, but this is tolerable given that the
entire section is only 512 KB on an allyesconfig build (which weighs in
at 500+ MB for the entire Image). Also, note that modules today carry
the replacement sequences in non-init sections as well, and any of
those that target init code will be emitted into init sections after
this change.
This fixes an early crash when booting an allyesconfig kernel on a
system where any of the alternatives sequences containing relative
branches are activated at boot (e.g., ARM64_HAS_PAN on TX2)
Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Andre Przywara <andre.przywara@arm.com> Cc: Dave P Martin <dave.martin@arm.com> Link: https://lore.kernel.org/r/20200630081921.13443-1-ardb@kernel.org Signed-off-by: Will Deacon <will@kernel.org>
Mark Brown [Wed, 24 Jun 2020 10:49:33 +0000 (11:49 +0100)]
kselftest: arm64: Remove redundant clean target
The arm64 signal tests generate warnings during build since both they and
the toplevel lib.mk define a clean target:
Makefile:25: warning: overriding recipe for target 'clean'
../../lib.mk:126: warning: ignoring old recipe for target 'clean'
Since the inclusion of lib.mk is in the signal Makefile there is no
situation where this warning could be avoided so just remove the redundant
clean target.
arm64: Don't insert a BTI instruction at inner labels
Some ftrace features are broken since commit 714a8d02ca4d ("arm64: asm:
Override SYM_FUNC_START when building the kernel with BTI"). For example
the function_graph tracer:
When ftrace_modify_graph_caller() attempts to write a branch at
ftrace_graph_call, it finds the "BTI J" instruction inserted by
SYM_INNER_LABEL() instead of a NOP, and aborts.
It turns out we don't currently need the BTI landing pads inserted by
SYM_INNER_LABEL:
* ftrace_call and ftrace_graph_call are only used for runtime patching
of the active tracer. The patched code is not reached from a branch.
* install_el2_stub is reached from a CBZ instruction, which doesn't
change PSTATE.BTYPE.
* __guest_exit is reached from B instructions in the hyp-entry vectors,
which aren't subject to BTI checks either.
Remove the BTI annotation from SYM_INNER_LABEL.
Fixes: 714a8d02ca4d ("arm64: asm: Override SYM_FUNC_START when building the kernel with BTI") Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org> Reviewed-by: Mark Brown <broonie@kernel.org> Link: https://lore.kernel.org/r/20200624112253.1602786-1-jean-philippe@linaro.org Signed-off-by: Will Deacon <will@kernel.org>
Will Deacon [Wed, 24 Jun 2020 12:23:10 +0000 (13:23 +0100)]
arm64: vdso: Only pass --no-eh-frame-hdr when linker supports it
Commit 87676cfca141 ("arm64: vdso: Disable dwarf unwinding through the
sigreturn trampoline") unconditionally passes the '--no-eh-frame-hdr'
option to the linker when building the native vDSO in an attempt to
prevent generation of the .eh_frame_hdr section, the presence of which
has been implicated in segfaults originating from the libgcc unwinder.
Unfortunately, not all versions of binutils support this option, which
has been shown to cause build failures in linux-next:
| CALL scripts/atomic/check-atomics.sh
| CALL scripts/checksyscalls.sh
| LD arch/arm64/kernel/vdso/vdso.so.dbg
| ld: unrecognized option '--no-eh-frame-hdr'
| ld: use the --help option for usage information
| arch/arm64/kernel/vdso/Makefile:64: recipe for target
| 'arch/arm64/kernel/vdso/vdso.so.dbg' failed
| make[1]: *** [arch/arm64/kernel/vdso/vdso.so.dbg] Error 1
| arch/arm64/Makefile:175: recipe for target 'vdso_prepare' failed
| make: *** [vdso_prepare] Error 2
Only link the vDSO with '--no-eh-frame-hdr' when the linker supports it.
If we end up with the section due to linker defaults, the absence of CFI
information in the sigreturn trampoline will prevent the unwinder from
breaking.
Link: https://lore.kernel.org/r/7a7e31a8-9a7b-2428-ad83-2264f20bdc2d@hisilicon.com Fixes: 87676cfca141 ("arm64: vdso: Disable dwarf unwinding through the sigreturn trampoline") Reported-by: Shaokun Zhang <zhangshaokun@hisilicon.com> Tested-by: Jon Hunter <jonathanh@nvidia.com> Signed-off-by: Will Deacon <will@kernel.org>
Mark Brown [Fri, 19 Jun 2020 12:35:50 +0000 (13:35 +0100)]
arm64: Depend on newer binutils when building PAC
Versions of binutils prior to 2.33.1 don't understand the ELF notes that
are added by modern compilers to indicate the PAC and BTI options used
to build the code. This causes them to emit large numbers of warnings in
the form:
during the kernel build which is currently causing quite a bit of
disruption for automated build testing using clang.
In commit 15cd0e675f3f76b (arm64: Kconfig: ptrauth: Add binutils version
check to fix mismatch) we added a dependency on binutils to avoid this
issue when building with versions of GCC that emit the notes but did not
do so for clang as it was believed that the existing check for
.cfi_negate_ra_state was already requiring a new enough binutils. This
does not appear to be the case for some versions of binutils (eg, the
binutils in Debian 10) so instead refactor so we require a new enough
GNU binutils in all cases other than when we are using an old GCC
version that does not emit notes.
Other, more exotic, combinations of tools are possible such as using
clang, lld and gas together are possible and may have further problems
but rather than adding further version checks it looks like the most
robust thing will be to just test that we can build cleanly with the
configured tools but that will require more review and discussion so do
this for now to address the immediate problem disrupting build testing.
Will Deacon [Mon, 22 Jun 2020 12:09:49 +0000 (13:09 +0100)]
arm64: compat: Always use sigpage for sigreturn trampoline
The 32-bit sigreturn trampoline in the compat sigpage matches the binary
representation of the arch/arm/ sigpage exactly. This is important for
debuggers (e.g. GDB) and unwinders (e.g. libunwind) since they rely
on matching the instruction sequence in order to identify that they are
unwinding through a signal. The same cannot be said for the sigreturn
trampoline in the compat vDSO, which defeats the unwinder heuristics and
instead attempts to use unwind directives for the unwinding. This is in
contrast to arch/arm/, which never uses the vDSO for sigreturn.
Ensure compatibility with arch/arm/ and existing unwinders by always
using the sigpage for the sigreturn trampoline, regardless of the
presence of the compat vDSO.
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Will Deacon <will@kernel.org>
Will Deacon [Mon, 22 Jun 2020 11:35:41 +0000 (12:35 +0100)]
arm64: compat: Allow 32-bit vdso and sigpage to co-exist
In preparation for removing the signal trampoline from the compat vDSO,
allow the sigpage and the compat vDSO to co-exist.
For the moment the vDSO signal trampoline will still be used when built.
Subsequent patches will move to the sigpage consistently.
Acked-by: Dave Martin <Dave.Martin@arm.com> Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Will Deacon <will@kernel.org>
Will Deacon [Mon, 22 Jun 2020 19:24:22 +0000 (20:24 +0100)]
arm64: vdso: Disable dwarf unwinding through the sigreturn trampoline
Commit 7e9f5e6629f6 ("arm64: vdso: Add --eh-frame-hdr to ldflags") results
in a .eh_frame_hdr section for the vDSO, which in turn causes the libgcc
unwinder to unwind out of signal handlers using the .eh_frame information
populated by our .cfi directives. In conjunction with a4eb355a3fda
("arm64: vdso: Fix CFI directives in sigreturn trampoline"), this has
been shown to cause segmentation faults originating from within the
unwinder during thread cancellation:
| Thread 14 "virtio-net-rx" received signal SIGSEGV, Segmentation fault.
| 0x0000000000435e24 in uw_frame_state_for ()
| (gdb) bt
| #0 0x0000000000435e24 in uw_frame_state_for ()
| #1 0x0000000000436e88 in _Unwind_ForcedUnwind_Phase2 ()
| #2 0x00000000004374d8 in _Unwind_ForcedUnwind ()
| #3 0x0000000000428400 in __pthread_unwind (buf=<optimized out>) at unwind.c:121
| #4 0x0000000000429808 in __do_cancel () at ./pthreadP.h:304
| #5 sigcancel_handler (sig=32, si=0xffff33c743f0, ctx=<optimized out>) at nptl-init.c:200
| #6 sigcancel_handler (sig=<optimized out>, si=0xffff33c743f0, ctx=<optimized out>) at nptl-init.c:165
| #7 <signal handler called>
| #8 futex_wait_cancelable (private=0, expected=0, futex_word=0x3890b708) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
After considerable bashing of heads, it appears that our CFI directives
for unwinding out of the sigreturn trampoline are only processed by libgcc
when both a .eh_frame_hdr section is present *and* the mysterious NOP is
covered by an entry in .eh_frame. With both of these now in place, it has
highlighted that our CFI directives are not comprehensive enough to
restore the stack pointer of the interrupted context. This results in libgcc
falling back to an arm64-specific unwinder after computing a bogus PC value
from the unwind tables. The unwinder promptly dereferences this bogus address
in an attempt to see if the pointed-to instruction sequence looks like
the sigreturn trampoline.
Restore the old unwind behaviour, which relied solely on heuristics in
the unwinder, by removing the .eh_frame_hdr section from the vDSO and
commenting out the insufficient CFI directives for now. Add comments to
explain the current, miserable state of affairs.
Cc: Tamas Zsoldos <tamas.zsoldos@arm.com> Cc: Szabolcs Nagy <szabolcs.nagy@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Daniel Kiss <daniel.kiss@arm.com> Acked-by: Dave Martin <Dave.Martin@arm.com> Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Reported-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Will Deacon <will@kernel.org>
Will Deacon [Fri, 29 May 2020 13:12:18 +0000 (14:12 +0100)]
arm64: hw_breakpoint: Don't invoke overflow handler on uaccess watchpoints
Unprivileged memory accesses generated by the so-called "translated"
instructions (e.g. STTR) at EL1 can cause EL0 watchpoints to fire
unexpectedly if kernel debugging is enabled. In such cases, the
hw_breakpoint logic will invoke the user overflow handler which will
typically raise a SIGTRAP back to the current task. This is futile when
returning back to the kernel because (a) the signal won't have been
delivered and (b) userspace can't handle the thing anyway.
Avoid invoking the user overflow handler for watchpoints triggered by
kernel uaccess routines, and instead single-step over the faulting
instruction as we would if no overflow handler had been installed.
(Fixes tag identifies the introduction of unprivileged memory accesses,
which exposed this latent bug in the hw_breakpoint code)
Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: James Morse <james.morse@arm.com> Fixes: 57f4959bad0a ("arm64: kernel: Add support for User Access Override") Reported-by: Luis Machado <luis.machado@linaro.org> Signed-off-by: Will Deacon <will@kernel.org>
Will Deacon [Tue, 16 Jun 2020 18:03:49 +0000 (19:03 +0100)]
arm64: bti: Require clang >= 10.0.1 for in-kernel BTI support
Unfortunately, most versions of clang that support BTI are capable of
miscompiling the kernel when converting a switch statement into a jump
table. As an example, attempting to spawn a KVM guest results in a panic:
Unfortunately, this results in a fatal exception because paciasp is
compatible only with branch-and-link (call) instructions and not simple
indirect branches.
A fix is being merged into Clang 10.0.1 so that a 'bti j' instruction is
emitted as an explicit landing pad in this situation. Make in-kernel
BTI depend on that compiler version when building with clang.
Will Deacon [Tue, 16 Jun 2020 17:29:11 +0000 (18:29 +0100)]
arm64: sve: Fix build failure when ARM64_SVE=y and SYSCTL=n
When I squashed the 'allnoconfig' compiler warning about the
set_sve_default_vl() function being defined but not used in commit 1e570f512cbd ("arm64/sve: Eliminate data races on sve_default_vl"), I
accidentally broke the build for configs where ARM64_SVE is enabled, but
SYSCTL is not.
Fix this by only compiling the SVE sysctl support if both CONFIG_SVE=y
and CONFIG_SYSCTL=y.
Will Deacon [Mon, 15 Jun 2020 15:27:43 +0000 (16:27 +0100)]
arm64: pgtable: Clear the GP bit for non-executable kernel pages
Commit cca98e9f8b5e ("mm: enforce that vmap can't map pages executable")
introduced 'pgprot_nx(prot)' for arm64 but collided silently with the
BTI support during the merge window, which endeavours to clear the GP
bit for non-executable kernel mappings in set_memory_nx().
For consistency between the two APIs, clear the GP bit in pgprot_nx().
Shyam Thombre [Wed, 10 Jun 2020 11:09:44 +0000 (16:39 +0530)]
arm64: mm: reset address tag set by kasan sw tagging
KASAN sw tagging sets a random tag of 8 bits in the top byte of the pointer
returned by the memory allocating functions. So for the functions unaware
of this change, the top 8 bits of the address must be reset which is done
by the function arch_kasan_reset_tag().
Will Deacon [Mon, 15 Jun 2020 11:23:16 +0000 (12:23 +0100)]
arm64: traps: Dump registers prior to panic() in bad_mode()
When panicing due to an unknown/unhandled exception at EL1, dump the
registers of the faulting context so that it's easier to figure out
what went wrong. In particular, this makes it a lot easier to debug
in-kernel BTI failures since it pretty-prints PSTATE.BTYPE in the crash
log.
Dave Martin [Wed, 10 Jun 2020 17:03:10 +0000 (18:03 +0100)]
arm64/sve: Eliminate data races on sve_default_vl
sve_default_vl can be modified via the /proc/sys/abi/sve_default_vl
sysctl concurrently with use, and modified concurrently by multiple
threads.
Adding a lock for this seems overkill, and I don't want to think any
more than necessary, so just define wrappers using READ_ONCE()/
WRITE_ONCE().
This will avoid the possibility of torn accesses and repeated loads
and stores.
There's no evidence yet that this is going wrong in practice: this
is just hygiene. For generic sysctl users, it would be better to
build this kind of thing into the sysctl common code somehow.
Dave Martin [Wed, 10 Jun 2020 17:03:09 +0000 (18:03 +0100)]
docs/arm64: Fix typo'd #define in sve.rst
sve.rst describes a flag PR_SVE_SET_VL_INHERIT for the
PR_SVE_SET_VL prctl, but there is no flag of this name. The flag
is shared between the _GET and _SET calls, so the _SET prefix was
dropped, giving the name PR_SVE_VL_INHERIT in the headers.
Ard Biesheuvel [Mon, 15 Jun 2020 10:19:39 +0000 (12:19 +0200)]
arm64: remove TEXT_OFFSET randomization
TEXT_OFFSET was recently changed to 0x0, in preparation for its removal
at a later stage, and a warning is emitted into the kernel log when the
bootloader appears to have failed to take the TEXT_OFFSET image header
value into account.
Ironically, this warning itself fails to take TEXT_OFFSET into account,
and compares the kernel image's alignment modulo 2M against a hardcoded
value of 0x0, and so the warning will trigger spuriously when TEXT_OFFSET
randomization is enabled.
Given the intent to get rid of TEXT_OFFSET entirely, let's fix this
oversight by just removing support for TEXT_OFFSET randomization.
Linus Torvalds [Sun, 14 Jun 2020 18:39:31 +0000 (11:39 -0700)]
Merge tag 'LSM-add-setgid-hook-5.8-author-fix' of git://github.com/micah-morton/linux
Pull SafeSetID update from Micah Morton:
"Add additional LSM hooks for SafeSetID
SafeSetID is capable of making allow/deny decisions for set*uid calls
on a system, and we want to add similar functionality for set*gid
calls.
The work to do that is not yet complete, so probably won't make it in
for v5.8, but we are looking to get this simple patch in for v5.8
since we have it ready.
We are planning on the rest of the work for extending the SafeSetID
LSM being merged during the v5.9 merge window"
* tag 'LSM-add-setgid-hook-5.8-author-fix' of git://github.com/micah-morton/linux:
security: Add LSM hooks to set*gid syscalls
Thomas Cedeno [Tue, 9 Jun 2020 17:22:13 +0000 (10:22 -0700)]
security: Add LSM hooks to set*gid syscalls
The SafeSetID LSM uses the security_task_fix_setuid hook to filter
set*uid() syscalls according to its configured security policy. In
preparation for adding analagous support in the LSM for set*gid()
syscalls, we add the requisite hook here. Tested by putting print
statements in the security_task_fix_setgid hook and seeing them get hit
during kernel boot.
Signed-off-by: Thomas Cedeno <thomascedeno@google.com> Signed-off-by: Micah Morton <mortonm@chromium.org>
Linus Torvalds [Sun, 14 Jun 2020 16:47:25 +0000 (09:47 -0700)]
Merge tag 'for-5.8-part2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs updates from David Sterba:
"This reverts the direct io port to iomap infrastructure of btrfs
merged in the first pull request. We found problems in invalidate page
that don't seem to be fixable as regressions or without changing iomap
code that would not affect other filesystems.
There are four reverts in total, but three of them are followup
cleanups needed to revert a43a67a2d715 cleanly. The result is the
buffer head based implementation of direct io.
Reverts are not great, but under current circumstances I don't see
better options"
* tag 'for-5.8-part2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
Revert "btrfs: switch to iomap_dio_rw() for dio"
Revert "fs: remove dio_end_io()"
Revert "btrfs: remove BTRFS_INODE_READDIO_NEED_LOCK"
Revert "btrfs: split btrfs_direct_IO to read and write part"
2) RXRPC fails to send norigications, from David Howells.
3) MPTCP RM_ADDR parsing has an off by one pointer error, fix from
Geliang Tang.
4) Fix crash when using MSG_PEEK with sockmap, from Anny Hu.
5) The ucc_geth driver needs __netdev_watchdog_up exported, from
Valentin Longchamp.
6) Fix hashtable memory leak in dccp, from Wang Hai.
7) Fix how nexthops are marked as FDB nexthops, from David Ahern.
8) Fix mptcp races between shutdown and recvmsg, from Paolo Abeni.
9) Fix crashes in tipc_disc_rcv(), from Tuong Lien.
10) Fix link speed reporting in iavf driver, from Brett Creeley.
11) When a channel is used for XSK and then reused again later for XSK,
we forget to clear out the relevant data structures in mlx5 which
causes all kinds of problems. Fix from Maxim Mikityanskiy.
12) Fix memory leak in genetlink, from Cong Wang.
13) Disallow sockmap attachments to UDP sockets, it simply won't work.
From Lorenz Bauer.
* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (83 commits)
net: ethernet: ti: ale: fix allmulti for nu type ale
net: ethernet: ti: am65-cpsw-nuss: fix ale parameters init
net: atm: Remove the error message according to the atomic context
bpf: Undo internal BPF_PROBE_MEM in BPF insns dump
libbpf: Support pre-initializing .bss global variables
tools/bpftool: Fix skeleton codegen
bpf: Fix memlock accounting for sock_hash
bpf: sockmap: Don't attach programs to UDP sockets
bpf: tcp: Recv() should return 0 when the peer socket is closed
ibmvnic: Flush existing work items before device removal
genetlink: clean up family attributes allocations
net: ipa: header pad field only valid for AP->modem endpoint
net: ipa: program upper nibbles of sequencer type
net: ipa: fix modem LAN RX endpoint id
net: ipa: program metadata mask differently
ionic: add pcie_print_link_status
rxrpc: Fix race between incoming ACK parser and retransmitter
net/mlx5: E-Switch, Fix some error pointer dereferences
net/mlx5: Don't fail driver on failure to create debugfs
net/mlx5e: CT: Fix ipv6 nat header rewrite actions
...
This patch reverts the main part of switching direct io implementation
to iomap infrastructure. There's a problem in invalidate page that
couldn't be solved as regression in this development cycle.
The problem occurs when buffered and direct io are mixed, and the ranges
overlap. Although this is not recommended, filesystems implement
measures or fallbacks to make it somehow work. In this case, fallback to
buffered IO would be an option for btrfs (this already happens when
direct io is done on compressed data), but the change would be needed in
the iomap code, bringing new semantics to other filesystems.
Another problem arises when again the buffered and direct ios are mixed,
invalidation fails, then -EIO is set on the mapping and fsync will fail,
though there's no real error.
There have been discussions how to fix that, but revert seems to be the
least intrusive option.
net: ethernet: ti: ale: fix allmulti for nu type ale
On AM65xx MCU CPSW2G NUSS and 66AK2E/L NUSS allmulti setting does not allow
unregistered mcast packets to pass.
This happens, because ALE VLAN entries on these SoCs do not contain port
masks for reg/unreg mcast packets, but instead store indexes of
ALE_VLAN_MASK_MUXx_REG registers which intended for store port masks for
reg/unreg mcast packets.
This path was missed by commit 9d1f6447274f ("net: ethernet: ti: ale: fix
seeing unreg mcast packets with promisc and allmulti disabled").
Hence, fix it by taking into account ALE type in cpsw_ale_set_allmulti().
Fixes: 9d1f6447274f ("net: ethernet: ti: ale: fix seeing unreg mcast packets with promisc and allmulti disabled") Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com> Signed-off-by: David S. Miller <davem@davemloft.net>
net: ethernet: ti: am65-cpsw-nuss: fix ale parameters init
The ALE parameters structure is created on stack, so it has to be reset
before passing to cpsw_ale_create() to avoid garbage values.
Fixes: 93a76530316a ("net: ethernet: ti: introduce am65x/j721e gigabit eth subsystem driver") Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Linus Torvalds [Sat, 13 Jun 2020 20:43:56 +0000 (13:43 -0700)]
Merge tag '5.8-rc-smb3-fixes-part2' of git://git.samba.org/sfrench/cifs-2.6
Pull more cifs updates from Steve French:
"12 cifs/smb3 fixes, 2 for stable.
- add support for idsfromsid on create and chgrp/chown allowing
ability to save owner information more naturally for some workloads
- improve query info (getattr) when SMB3.1.1 posix extensions are
negotiated by using new query info level"
* tag '5.8-rc-smb3-fixes-part2' of git://git.samba.org/sfrench/cifs-2.6:
smb3: Add debug message for new file creation with idsfromsid mount option
cifs: fix chown and chgrp when idsfromsid mount option enabled
smb3: allow uid and gid owners to be set on create with idsfromsid mount option
smb311: Add tracepoints for new compound posix query info
smb311: add support for using info level for posix extensions query
smb311: Add support for lookup with posix extensions query info
smb311: Add support for SMB311 query info (non-compounded)
SMB311: Add support for query info using posix extensions (level 100)
smb3: add indatalen that can be a non-zero value to calculation of credit charge in smb2 ioctl
smb3: fix typo in mount options displayed in /proc/mounts
cifs: Add get_security_type_str function to return sec type.
smb3: extend fscache mount volume coherency check
Linus Torvalds [Sat, 13 Jun 2020 20:32:40 +0000 (13:32 -0700)]
doc: don't use deprecated "---help---" markers in target docs
I'm not convinced the script makes useful automaed help lines anyway,
but since we're trying to deprecate the use of "---help---" in Kconfig
files, let's fix the doc example code too.
See commit a7f7f6248d97 ("treewide: replace '---help---' in Kconfig
files with 'help'")
Linus Torvalds [Sat, 13 Jun 2020 20:29:16 +0000 (13:29 -0700)]
Merge tag 'kbuild-v5.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull more Kbuild updates from Masahiro Yamada:
- fix build rules in binderfs sample
- fix build errors when Kbuild recurses to the top Makefile
- covert '---help---' in Kconfig to 'help'
* tag 'kbuild-v5.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
treewide: replace '---help---' in Kconfig files with 'help'
kbuild: fix broken builds because of GZIP,BZIP2,LZOP variables
samples: binderfs: really compile this sample and fix build issues
Linus Torvalds [Sat, 13 Jun 2020 20:17:49 +0000 (13:17 -0700)]
Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi
Pull more SCSI updates from James Bottomley:
"This is the set of changes collected since just before the merge
window opened. It's mostly minor fixes in drivers.
The one non-driver set is the three optical disk (sr) changes where
two are error path fixes and one is a helper conversion.
The big driver change is the hpsa compat_alloc_userspace rework by Al
so he can kill the remaining user. This has been tested and acked by
the maintainer"
* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (21 commits)
scsi: acornscsi: Fix an error handling path in acornscsi_probe()
scsi: storvsc: Remove memset before memory freeing in storvsc_suspend()
scsi: cxlflash: Remove an unnecessary NULL check
scsi: ibmvscsi: Don't send host info in adapter info MAD after LPM
scsi: sr: Fix sr_probe() missing deallocate of device minor
scsi: sr: Fix sr_probe() missing mutex_destroy
scsi: st: Convert convert get_user_pages() --> pin_user_pages()
scsi: target: Rename target_setup_cmd_from_cdb() to target_cmd_parse_cdb()
scsi: target: Fix NULL pointer dereference
scsi: target: Initialize LUN in transport_init_se_cmd()
scsi: target: Factor out a new helper, target_cmd_init_cdb()
scsi: hpsa: hpsa_ioctl(): Tidy up a bit
scsi: hpsa: Get rid of compat_alloc_user_space()
scsi: hpsa: Don't bother with vmalloc for BIG_IOCTL_Command_struct
scsi: hpsa: Lift {BIG_,}IOCTL_Command_struct copy{in,out} into hpsa_ioctl()
scsi: ufs: Remove redundant urgent_bkop_lvl initialization
scsi: ufs: Don't update urgent bkops level when toggling auto bkops
scsi: qedf: Remove redundant initialization of variable rc
scsi: mpt3sas: Fix memset() in non-RDPQ mode
scsi: iscsi: Fix reference count leak in iscsi_boot_create_kobj
...
Linus Torvalds [Sat, 13 Jun 2020 20:12:38 +0000 (13:12 -0700)]
Merge branch 'i2c/for-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux
Pull i2c updates from Wolfram Sang:
"I2C has quite some patches for you this time. I hope it is the move to
per-driver-maintainers which is now showing results. We will see.
The big news is two new drivers (Nuvoton NPCM and Qualcomm CCI),
larger refactoring of the Designware, Tegra, and PXA drivers, the
Cadence driver supports being a slave now, and there is support to
instanciate SPD eeproms for well-known cases (which will be
user-visible because the i801 driver supports it), and some
devm_platform_ioremap_resource() conversions which blow up the
diffstat.
Note that I applied the Nuvoton driver quite late, so some minor fixup
patches arrived during the merge window. I chose to apply them right
away because they were trivial"
* 'i2c/for-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (109 commits)
i2c: Drop stray comma in MODULE_AUTHOR statements
i2c: npcm7xx: npcm_i2caddr[] can be static
MAINTAINERS: npcm7xx: Add maintainer for Nuvoton NPCM BMC
i2c: npcm7xx: Fix a couple of error codes in probe
i2c: icy: Fix build with CONFIG_AMIGA_PCMCIA=n
i2c: npcm7xx: Remove unnecessary parentheses
i2c: npcm7xx: Add support for slave mode for Nuvoton
i2c: npcm7xx: Add Nuvoton NPCM I2C controller driver
dt-bindings: i2c: npcm7xx: add NPCM I2C controller
i2c: pxa: don't error out if there's no pinctrl
i2c: add 'single-master' property to generic bindings
i2c: designware: Add Baikal-T1 System I2C support
i2c: designware: Move reg-space remapping into a dedicated function
i2c: designware: Retrieve quirk flags as early as possible
i2c: designware: Convert driver to using regmap API
i2c: designware: Discard Cherry Trail model flag
i2c: designware: Add Baytrail sem config DW I2C platform dependency
i2c: designware: slave: Set DW I2C core module dependency
i2c: designware: Use `-y` to build multi-object modules
dt-bindings: i2c: dw: Add Baikal-T1 SoC I2C controller
...
Linus Torvalds [Sat, 13 Jun 2020 20:09:38 +0000 (13:09 -0700)]
Merge tag 'media/v5.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media
Pull more media updates from Mauro Carvalho Chehab:
- a set of atomisp patches. They remove several abstraction layers, and
fixes clang and gcc warnings (that were hidden via some macros that
were disabling 4 or 5 types of warnings there). There are also some
important fixes and sensor auto-detection on newer BIOSes via ACPI
_DCM tables.
- some fixes
* tag 'media/v5.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (95 commits)
media: rkvdec: Fix H264 scaling list order
media: v4l2-ctrls: Unset correct HEVC loop filter flag
media: videobuf2-dma-contig: fix bad kfree in vb2_dma_contig_clear_max_seg_size
media: v4l2-subdev.rst: correct information about v4l2 events
media: s5p-mfc: Properly handle dma_parms for the allocated devices
media: medium: cec: Make MEDIA_CEC_SUPPORT default to n if !MEDIA_SUPPORT
media: cedrus: Implement runtime PM
media: cedrus: Program output format during each run
media: atomisp: improve ACPI/DMI detection logs
media: Revert "media: atomisp: add Asus Transform T101HA ACPI vars"
media: Revert "media: atomisp: Add some ACPI detection info"
media: atomisp: improve sensor detection code to use _DSM table
media: atomisp: get rid of an iomem abstraction layer
media: atomisp: get rid of a string_support.h abstraction layer
media: atomisp: use strscpy() instead of less secure variants
media: atomisp: set DFS to MAX if sensor doesn't report fps
media: atomisp: use different dfs failed messages
media: atomisp: change the detection of ISP2401 at runtime
media: atomisp: use macros from intel-family.h
media: atomisp: don't set hpll_freq twice with different values
...
Linus Torvalds [Sat, 13 Jun 2020 20:04:36 +0000 (13:04 -0700)]
Merge tag 'libnvdimm-for-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
Pull libnvdimm updates from Dan Williams:
"Small collection of cleanups to rework usage of ->queuedata and the
GUID api"
* tag 'libnvdimm-for-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
nvdimm/pmem: stop using ->queuedata
nvdimm/btt: stop using ->queuedata
nvdimm/blk: stop using ->queuedata
libnvdimm: Replace guid_copy() with import_guid() where it makes sense
Linus Torvalds [Sat, 13 Jun 2020 19:44:30 +0000 (12:44 -0700)]
Merge tag 'iomap-5.8-merge-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux
Pull iomap fix from Darrick Wong:
"A single iomap bug fix for a variable type mistake on 32-bit
architectures, fixing an integer overflow problem in the unshare
actor"
* tag 'iomap-5.8-merge-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
iomap: Fix unsharing of an extent >2GB on a 32-bit machine
Linus Torvalds [Sat, 13 Jun 2020 17:55:29 +0000 (10:55 -0700)]
Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm
Pull ARM fixes from Russell King:
- fix for "hex" Kconfig default to use 0x0 rather than 0 to allow these
to be removed from defconfigs
- fix from Ard Biesheuvel for EFI HYP mode booting
* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
ARM: 8985/1: efi/decompressor: deal with HYP mode boot gracefully
ARM: 8984/1: Kconfig: set default ZBOOT_ROM_TEXT/BSS value to 0x0
Linus Torvalds [Sat, 13 Jun 2020 17:51:29 +0000 (10:51 -0700)]
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mattst88/alpha
Pull alpha updates from Matt Turner:
"A few changes for alpha. They're mostly small janitorial fixes but
there's also a build fix and most notably a patch from Mikulas that
fixes a hang on boot on the Avanti platform, which required quite a
bit of work and review"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mattst88/alpha:
alpha: Fix build around srm_sysrq_reboot_op
alpha: c_next should increase position index
alpha: Replace sg++ with sg = sg_next(sg)
alpha: fix memory barriers so that they conform to the specification
alpha: remove unneeded semicolon in sys_eiger.c
alpha: remove unneeded semicolon in osf_sys.c
alpha: Replace strncmp with str_has_prefix
alpha: fix rtc port ranges
alpha: Kconfig: pedantic formatting
Linus Torvalds [Sat, 13 Jun 2020 17:21:00 +0000 (10:21 -0700)]
Merge tag 'ras-core-2020-06-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 RAS updates from Thomas Gleixner:
"RAS updates from Borislav Petkov:
- Unmap a whole guest page if an MCE is encountered in it to avoid
follow-on MCEs leading to the guest crashing, by Tony Luck.
This change collided with the entry changes and the merge
resolution would have been rather unpleasant. To avoid that the
entry branch was merged in before applying this. The resulting code
did not change over the rebase.
- AMD MCE error thresholding machinery cleanup and hotplug
sanitization, by Thomas Gleixner.
- Change the MCE notifiers to denote whether they have handled the
error and not break the chain early by returning NOTIFY_STOP, thus
giving the opportunity for the later handlers in the chain to see
it. By Tony Luck.
- Add AMD family 0x17, models 0x60-6f support, by Alexander Monakov.
- Last but not least, the usual round of fixes and improvements"
* tag 'ras-core-2020-06-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
x86/mce/dev-mcelog: Fix -Wstringop-truncation warning about strncpy()
x86/{mce,mm}: Unmap the entire page if the whole page is affected and poisoned
EDAC/amd64: Add AMD family 17h model 60h PCI IDs
hwmon: (k10temp) Add AMD family 17h model 60h PCI match
x86/amd_nb: Add AMD family 17h model 60h PCI IDs
x86/mcelog: Add compat_ioctl for 32-bit mcelog support
x86/mce: Drop bogus comment about mce.kflags
x86/mce: Fixup exception only for the correct MCEs
EDAC: Drop the EDAC report status checks
x86/mce: Add mce=print_all option
x86/mce: Change default MCE logger to check mce->kflags
x86/mce: Fix all mce notifiers to update the mce->kflags bitmask
x86/mce: Add a struct mce.kflags field
x86/mce: Convert the CEC to use the MCE notifier
x86/mce: Rename "first" function as "early"
x86/mce/amd, edac: Remove report_gart_errors
x86/mce/amd: Make threshold bank setting hotplug robust
x86/mce/amd: Cleanup threshold device remove path
x86/mce/amd: Straighten CPU hotplug path
x86/mce/amd: Sanitize thresholding device creation hotplug path
...
Linus Torvalds [Sat, 13 Jun 2020 17:05:47 +0000 (10:05 -0700)]
Merge tag 'x86-entry-2020-06-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 entry updates from Thomas Gleixner:
"The x86 entry, exception and interrupt code rework
This all started about 6 month ago with the attempt to move the Posix
CPU timer heavy lifting out of the timer interrupt code and just have
lockless quick checks in that code path. Trivial 5 patches.
This unearthed an inconsistency in the KVM handling of task work and
the review requested to move all of this into generic code so other
architectures can share.
Valid request and solved with another 25 patches but those unearthed
inconsistencies vs. RCU and instrumentation.
Digging into this made it obvious that there are quite some
inconsistencies vs. instrumentation in general. The int3 text poke
handling in particular was completely unprotected and with the batched
update of trace events even more likely to expose to endless int3
recursion.
In parallel the RCU implications of instrumenting fragile entry code
came up in several discussions.
The conclusion of the x86 maintainer team was to go all the way and
make the protection against any form of instrumentation of fragile and
dangerous code pathes enforcable and verifiable by tooling.
A first batch of preparatory work hit mainline with commit d5f744f9a2ac ("Pull x86 entry code updates from Thomas Gleixner")
That (almost) full solution introduced a new code section
'.noinstr.text' into which all code which needs to be protected from
instrumentation of all sorts goes into. Any call into instrumentable
code out of this section has to be annotated. objtool has support to
validate this.
Kprobes now excludes this section fully which also prevents BPF from
fiddling with it and all 'noinstr' annotated functions also keep
ftrace off. The section, kprobes and objtool changes are already
merged.
The major changes coming with this are:
- Preparatory cleanups
- Annotating of relevant functions to move them into the
noinstr.text section or enforcing inlining by marking them
__always_inline so the compiler cannot misplace or instrument
them.
- Splitting and simplifying the idtentry macro maze so that it is
now clearly separated into simple exception entries and the more
interesting ones which use interrupt stacks and have the paranoid
handling vs. CR3 and GS.
- Move quite some of the low level ASM functionality into C code:
- enter_from and exit to user space handling. The ASM code now
calls into C after doing the really necessary ASM handling and
the return path goes back out without bells and whistels in
ASM.
- exception entry/exit got the equivivalent treatment
- move all IRQ tracepoints from ASM to C so they can be placed as
appropriate which is especially important for the int3
recursion issue.
- Consolidate the declaration and definition of entry points between
32 and 64 bit. They share a common header and macros now.
- Remove the extra device interrupt entry maze and just use the
regular exception entry code.
- All ASM entry points except NMI are now generated from the shared
header file and the corresponding macros in the 32 and 64 bit
entry ASM.
- The C code entry points are consolidated as well with the help of
DEFINE_IDTENTRY*() macros. This allows to ensure at one central
point that all corresponding entry points share the same
semantics. The actual function body for most entry points is in an
instrumentable and sane state.
There are special macros for the more sensitive entry points, e.g.
INT3 and of course the nasty paranoid #NMI, #MCE, #DB and #DF.
They allow to put the whole entry instrumentation and RCU handling
into safe places instead of the previous pray that it is correct
approach.
- The INT3 text poke handling is now completely isolated and the
recursion issue banned. Aside of the entry rework this required
other isolation work, e.g. the ability to force inline bsearch.
- Prevent #DB on fragile entry code, entry relevant memory and
disable it on NMI, #MC entry, which allowed to get rid of the
nested #DB IST stack shifting hackery.
- A few other cleanups and enhancements which have been made
possible through this and already merged changes, e.g.
consolidating and further restricting the IDT code so the IDT
table becomes RO after init which removes yet another popular
attack vector
- About 680 lines of ASM maze are gone.
There are a few open issues:
- An escape out of the noinstr section in the MCE handler which needs
some more thought but under the aspect that MCE is a complete
trainwreck by design and the propability to survive it is low, this
was not high on the priority list.
- Paravirtualization
When PV is enabled then objtool complains about a bunch of indirect
calls out of the noinstr section. There are a few straight forward
ways to fix this, but the other issues vs. general correctness were
more pressing than parawitz.
- KVM
KVM is inconsistent as well. Patches have been posted, but they
have not yet been commented on or picked up by the KVM folks.
- IDLE
Pretty much the same problems can be found in the low level idle
code especially the parts where RCU stopped watching. This was
beyond the scope of the more obvious and exposable problems and is
on the todo list.
The lesson learned from this brain melting exercise to morph the
evolved code base into something which can be validated and understood
is that once again the violation of the most important engineering
principle "correctness first" has caused quite a few people to spend
valuable time on problems which could have been avoided in the first
place. The "features first" tinkering mindset really has to stop.
With that I want to say thanks to everyone involved in contributing to
this effort. Special thanks go to the following people (alphabetical
order): Alexandre Chartre, Andy Lutomirski, Borislav Petkov, Brian
Gerst, Frederic Weisbecker, Josh Poimboeuf, Juergen Gross, Lai
Jiangshan, Macro Elver, Paolo Bonzin,i Paul McKenney, Peter Zijlstra,
Vitaly Kuznetsov, and Will Deacon"
* tag 'x86-entry-2020-06-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (142 commits)
x86/entry: Force rcu_irq_enter() when in idle task
x86/entry: Make NMI use IDTENTRY_RAW
x86/entry: Treat BUG/WARN as NMI-like entries
x86/entry: Unbreak __irqentry_text_start/end magic
x86/entry: __always_inline CR2 for noinstr
lockdep: __always_inline more for noinstr
x86/entry: Re-order #DB handler to avoid *SAN instrumentation
x86/entry: __always_inline arch_atomic_* for noinstr
x86/entry: __always_inline irqflags for noinstr
x86/entry: __always_inline debugreg for noinstr
x86/idt: Consolidate idt functionality
x86/idt: Cleanup trap_init()
x86/idt: Use proper constants for table size
x86/idt: Add comments about early #PF handling
x86/idt: Mark init only functions __init
x86/entry: Rename trace_hardirqs_off_prepare()
x86/entry: Clarify irq_{enter,exit}_rcu()
x86/entry: Remove DBn stacks
x86/entry: Remove debug IDT frobbing
x86/entry: Optimize local_db_save() for virt
...
Masahiro Yamada [Sat, 13 Jun 2020 16:50:22 +0000 (01:50 +0900)]
treewide: replace '---help---' in Kconfig files with 'help'
Since commit 84af7a6194e4 ("checkpatch: kconfig: prefer 'help' over
'---help---'"), the number of '---help---' has been gradually
decreasing, but there are still more than 2400 instances.
This commit finishes the conversion. While I touched the lines,
I also fixed the indentation.
There are a variety of indentation styles found.
a) 4 spaces + '---help---'
b) 7 spaces + '---help---'
c) 8 spaces + '---help---'
d) 1 space + 1 tab + '---help---'
e) 1 tab + '---help---' (correct indentation)
f) 1 tab + 1 space + '---help---'
g) 1 tab + 2 spaces + '---help---'
In order to convert all of them to 1 tab + 'help', I ran the
following commend:
$ find . -name 'Kconfig*' | xargs sed -i 's/^[[:space:]]*---help---/\thelp/'
Linus Torvalds [Sat, 13 Jun 2020 16:56:21 +0000 (09:56 -0700)]
Merge tag 'notifications-20200601' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
Pull notification queue from David Howells:
"This adds a general notification queue concept and adds an event
source for keys/keyrings, such as linking and unlinking keys and
changing their attributes.
Thanks to Debarshi Ray, we do have a pull request to use this to fix a
problem with gnome-online-accounts - as mentioned last time:
Without this, g-o-a has to constantly poll a keyring-based kerberos
cache to find out if kinit has changed anything.
[ There are other notification pending: mount/sb fsinfo notifications
for libmount that Karel Zak and Ian Kent have been working on, and
Christian Brauner would like to use them in lxc, but let's see how
this one works first ]
LSM hooks are included:
- A set of hooks are provided that allow an LSM to rule on whether or
not a watch may be set. Each of these hooks takes a different
"watched object" parameter, so they're not really shareable. The
LSM should use current's credentials. [Wanted by SELinux & Smack]
- A hook is provided to allow an LSM to rule on whether or not a
particular message may be posted to a particular queue. This is
given the credentials from the event generator (which may be the
system) and the watch setter. [Wanted by Smack]
I've provided SELinux and Smack with implementations of some of these
hooks.
WHY
===
Key/keyring notifications are desirable because if you have your
kerberos tickets in a file/directory, your Gnome desktop will monitor
that using something like fanotify and tell you if your credentials
cache changes.
However, we also have the ability to cache your kerberos tickets in
the session, user or persistent keyring so that it isn't left around
on disk across a reboot or logout. Keyrings, however, cannot currently
be monitored asynchronously, so the desktop has to poll for it - not
so good on a laptop. This facility will allow the desktop to avoid the
need to poll.
DESIGN DECISIONS
================
- The notification queue is built on top of a standard pipe. Messages
are effectively spliced in. The pipe is opened with a special flag:
pipe2(fds, O_NOTIFICATION_PIPE);
The special flag has the same value as O_EXCL (which doesn't seem
like it will ever be applicable in this context)[?]. It is given up
front to make it a lot easier to prohibit splice&co from accessing
the pipe.
[?] Should this be done some other way? I'd rather not use up a new
O_* flag if I can avoid it - should I add a pipe3() system call
instead?
Messages are then read out of the pipe using read().
- It should be possible to allow write() to insert data into the
notification pipes too, but this is currently disabled as the
kernel has to be able to insert messages into the pipe *without*
holding pipe->mutex and the code to make this work needs careful
auditing.
- sendfile(), splice() and vmsplice() are disabled on notification
pipes because of the pipe->mutex issue and also because they
sometimes want to revert what they just did - but one or more
notification messages might've been interleaved in the ring.
- The kernel inserts messages with the wait queue spinlock held. This
means that pipe_read() and pipe_write() have to take the spinlock
to update the queue pointers.
- Records in the buffer are binary, typed and have a length so that
they can be of varying size.
This allows multiple heterogeneous sources to share a common
buffer; there are 16 million types available, of which I've used
just a few, so there is scope for others to be used. Tags may be
specified when a watchpoint is created to help distinguish the
sources.
- Records are filterable as types have up to 256 subtypes that can be
individually filtered. Other filtration is also available.
- Notification pipes don't interfere with each other; each may be
bound to a different set of watches. Any particular notification
will be copied to all the queues that are currently watching for it
- and only those that are watching for it.
- When recording a notification, the kernel will not sleep, but will
rather mark a queue as having lost a message if there's
insufficient space. read() will fabricate a loss notification
message at an appropriate point later.
- The notification pipe is created and then watchpoints are attached
to it, using one of:
where in both cases, fd indicates the queue and the number after is
a tag between 0 and 255.
- Watches are removed if either the notification pipe is destroyed or
the watched object is destroyed. In the latter case, a message will
be generated indicating the enforced watch removal.
Things I want to avoid:
- Introducing features that make the core VFS dependent on the
network stack or networking namespaces (ie. usage of netlink).
- Dumping all this stuff into dmesg and having a daemon that sits
there parsing the output and distributing it as this then puts the
responsibility for security into userspace and makes handling
namespaces tricky. Further, dmesg might not exist or might be
inaccessible inside a container.
- Letting users see events they shouldn't be able to see.
TESTING AND MANPAGES
====================
- The keyutils tree has a pipe-watch branch that has keyctl commands
for making use of notifications. Proposed manual pages can also be
found on this branch, though a couple of them really need to go to
the main manpages repository instead.
If the kernel supports the watching of keys, then running "make
test" on that branch will cause the testing infrastructure to spawn
a monitoring process on the side that monitors a notifications pipe
for all the key/keyring changes induced by the tests and they'll
all be checked off to make sure they happened.
- A test program is provided (samples/watch_queue/watch_test) that
can be used to monitor for keyrings, mount and superblock events.
Information on the notifications is simply logged to stdout"
* tag 'notifications-20200601' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
smack: Implement the watch_key and post_notification hooks
selinux: Implement the watch_key security hook
keys: Make the KEY_NEED_* perms an enum rather than a mask
pipe: Add notification lossage handling
pipe: Allow buffers to be marked read-whole-or-error for notifications
Add sample notification program
watch_queue: Add a key/keyring notification facility
security: Add hooks to rule on setting a watch
pipe: Add general notification queue support
pipe: Add O_NOTIFICATION_PIPE
security: Add a hook for the point of notification insertion
uapi: General notification queue definitions
Ard Biesheuvel [Fri, 12 Jun 2020 10:21:35 +0000 (11:21 +0100)]
ARM: 8985/1: efi/decompressor: deal with HYP mode boot gracefully
EFI on ARM only supports short descriptors, and given that it mandates
that the MMU and caches are on, it is implied that booting in HYP mode
is not supported.
However, implementations of EFI exist (i.e., U-Boot) that ignore this
requirement, which is not entirely unreasonable, given that it makes
HYP mode inaccessible to the operating system.
So let's make sure that we can deal with this condition gracefully.
We already tolerate booting the EFI stub with the caches off (even
though this violates the EFI spec as well), and so we should deal
with HYP mode boot with MMU and caches either on or off.
- When the MMU and caches are on, we can ignore the HYP stub altogether,
since we can carry on executing at HYP. We do need to ensure that we
disable the MMU at HYP before entering the kernel proper.
- When the MMU and caches are off, we have to drop to SVC mode so that
we can set up the page tables using short descriptors. In this case,
we need to install the HYP stub as usual, so that we can return to HYP
mode before handing over to the kernel proper.
Tested-by: Heinrich Schuchardt <xypron.glpk@gmx.de> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Chris Packham [Tue, 9 Jun 2020 02:28:14 +0000 (03:28 +0100)]
ARM: 8984/1: Kconfig: set default ZBOOT_ROM_TEXT/BSS value to 0x0
ZBOOT_ROM_TEXT and ZBOOT_ROM_BSS are defined as 'hex' but had a default
of "0". Kconfig will helpfully expand a text entry of 0 to 0x0 but
because this is not the same as the default value it was treated as
being explicitly set when running 'make savedefconfig' so most arm
defconfigs have CONFIG_ZBOOT_ROM_TEXT=0x0 and CONFIG_ZBOOT_ROM_BSS=0x0.
Change the default to 0x0 which will mean next time the defconfigs are
re-generated the spurious config entries will be removed.
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Joerg Roedel [Thu, 11 Jun 2020 09:11:39 +0000 (11:11 +0200)]
alpha: Fix build around srm_sysrq_reboot_op
The patch introducing the struct was probably never compile tested,
because it sets a handler with a wrong function signature. Wrap the
handler into a functions with the correct signature to fix the build.
Fixes: 0f1c9688a194 ("tty/sysrq: alpha: export and use __sysrq_get_key_op()") Cc: Emil Velikov <emil.l.velikov@gmail.com> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Tested-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Matt Turner <mattst88@gmail.com>
Mikulas Patocka [Tue, 26 May 2020 14:47:49 +0000 (10:47 -0400)]
alpha: fix memory barriers so that they conform to the specification
The commits cd0e00c10672 and 92d7223a7423 broke boot on the Alpha Avanti
platform. The patches move memory barriers after a write before the write.
The result is that if there's iowrite followed by ioread, there is no
barrier between them.
The Alpha architecture allows reordering of the accesses to the I/O space,
and the missing barrier between write and read causes hang with serial
port and real time clock.
This patch makes barriers confiorm to the specification.
1. We add mb() before readX_relaxed and writeX_relaxed -
memory-barriers.txt claims that these functions must be ordered w.r.t.
each other. Alpha doesn't order them, so we need an explicit barrier.
2. We add mb() before reads from the I/O space - so that if there's a
write followed by a read, there should be a barrier between them.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Fixes: cd0e00c10672 ("alpha: io: reorder barriers to guarantee writeX() and iowriteX() ordering") Fixes: 92d7223a7423 ("alpha: io: reorder barriers to guarantee writeX() and iowriteX() ordering #2") Cc: stable@vger.kernel.org # v4.17+ Acked-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Reviewed-by: Maciej W. Rozycki <macro@linux-mips.org> Signed-off-by: Matt Turner <mattst88@gmail.com>
In commit b6b2735514bc
("tracing: Use str_has_prefix() instead of using fixed sizes")
the newly introduced str_has_prefix() was used
to replace error-prone strncmp(str, const, len).
Here fix codes with the same pattern.
Signed-off-by: Chuhong Yuan <hslester96@gmail.com> Signed-off-by: Matt Turner <mattst88@gmail.com>
Andrii Nakryiko [Fri, 12 Jun 2020 19:45:04 +0000 (12:45 -0700)]
libbpf: Support pre-initializing .bss global variables
Remove invalid assumption in libbpf that .bss map doesn't have to be updated
in kernel. With addition of skeleton and memory-mapped initialization image,
.bss doesn't have to be all zeroes when BPF map is created, because user-code
might have initialized those variables from user-space.
Andrii Nakryiko [Fri, 12 Jun 2020 20:16:03 +0000 (13:16 -0700)]
tools/bpftool: Fix skeleton codegen
Remove unnecessary check at the end of codegen() routine which makes codegen()
to always fail and exit bpftool with error code. Positive value of variable
n is not an indicator of a failure.
Fixes: 2c4779eff837 ("tools, bpftool: Exit on error in function codegen") Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Tobias Klauser <tklauser@distanz.ch> Link: https://lore.kernel.org/bpf/20200612201603.680852-1-andriin@fb.com
Sabrina Dubroca [Wed, 10 Jun 2020 10:19:43 +0000 (12:19 +0200)]
bpf: tcp: Recv() should return 0 when the peer socket is closed
If the peer is closed, we will never get more data, so
tcp_bpf_wait_data will get stuck forever. In case we passed
MSG_DONTWAIT to recv(), we get EAGAIN but we should actually get
0.
>From man 2 recv:
RETURN VALUE
When a stream socket peer has performed an orderly shutdown, the
return value will be 0 (the traditional "end-of-file" return).
This patch makes tcp_bpf_wait_data always return 1 when the peer
socket has been shutdown. Either we have data available, and it would
have returned 1 anyway, or there isn't, in which case we'll call
tcp_recvmsg which does the right thing in this situation.
Steve French [Fri, 12 Jun 2020 19:49:47 +0000 (14:49 -0500)]
smb3: Add debug message for new file creation with idsfromsid mount option
Pavel noticed that a debug message (disabled by default) in creating the security
descriptor context could be useful for new file creation owner fields
(as we already have for the mode) when using mount parm idsfromsid.
[38120.392272] CIFS: FYI: owner S-1-5-88-1-0, group S-1-5-88-2-0
[38125.792637] CIFS: FYI: owner S-1-5-88-1-1000, group S-1-5-88-2-1000
Also cleans up a typo in a comment
Signed-off-by: Steve French <stfrench@microsoft.com> Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Thomas Falcon [Fri, 12 Jun 2020 18:34:41 +0000 (13:34 -0500)]
ibmvnic: Flush existing work items before device removal
Ensure that all scheduled work items have completed before continuing
with device removal and after further event scheduling has been
halted. This patch fixes a bug where a scheduled driver reset event
is processed following device removal.
Signed-off-by: Thomas Falcon <tlfalcon@linux.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Cong Wang [Fri, 12 Jun 2020 07:16:55 +0000 (00:16 -0700)]
genetlink: clean up family attributes allocations
genl_family_rcv_msg_attrs_parse() and genl_family_rcv_msg_attrs_free()
take a boolean parameter to determine whether allocate/free the family
attrs. This is unnecessary as we can just check family->parallel_ops.
More importantly, callers would not need to worry about pairing these
parameters correctly after this patch.
And this fixes a memory leak, as after commit c36f05559104
("genetlink: fix memory leaks in genl_family_rcv_msg_dumpit()")
we call genl_family_rcv_msg_attrs_parse() for both parallel and
non-parallel cases.
Fixes: c36f05559104 ("genetlink: fix memory leaks in genl_family_rcv_msg_dumpit()") Reported-by: Ido Schimmel <idosch@idosch.org> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Reviewed-by: Ido Schimmel <idosch@mellanox.com> Tested-by: Ido Schimmel <idosch@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Linus Torvalds [Fri, 12 Jun 2020 19:38:18 +0000 (12:38 -0700)]
Merge branch 'proc-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull proc fix from Eric Biederman:
"Much to my surprise syzbot found a very old bug in proc that the
recent changes made easier to reproce. This bug is subtle enough it
looks like it fooled everyone who should know better"
* 'proc-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
proc: Use new_inode not new_inode_pseudo
Thomas Gleixner [Fri, 12 Jun 2020 13:55:00 +0000 (15:55 +0200)]
x86/entry: Force rcu_irq_enter() when in idle task
The idea of conditionally calling into rcu_irq_enter() only when RCU is
not watching turned out to be not completely thought through.
Paul noticed occasional premature end of grace periods in RCU torture
testing. Bisection led to the commit which made the invocation of
rcu_irq_enter() conditional on !rcu_is_watching().
It turned out that this conditional breaks RCU assumptions about the idle
task when the scheduler tick happens to be a nested interrupt. Nested
interrupts can happen when the first interrupt invokes softirq processing
on return which enables interrupts.
If that nested tick interrupt does not invoke rcu_irq_enter() then the
RCU's irq-nesting checks will believe that this interrupt came directly
from idle, which will cause RCU to report a quiescent state. Because this
interrupt instead came from a softirq handler which might have been
executing an RCU read-side critical section, this can cause the grace
period to end prematurely.
Change the condition from !rcu_is_watching() to is_idle_task(current) which
enforces that interrupts in the idle task unconditionally invoke
rcu_irq_enter() independent of the RCU state.
This is also correct vs. user mode entries in NOHZ full scenarios because
user mode entries bring RCU out of EQS and force the RCU irq nesting state
accounting to nested. As only the first interrupt can enter from user mode
a nested tick interrupt will enter from kernel mode and as the nesting
state accounting is forced to nesting it will not do anything stupid even
if rcu_irq_enter() has not been invoked.
Fixes: 3eeec3858488 ("x86/entry: Provide idtentry_entry/exit_cond_rcu()") Reported-by: "Paul E. McKenney" <paulmck@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: "Paul E. McKenney" <paulmck@kernel.org> Reviewed-by: "Paul E. McKenney" <paulmck@kernel.org> Acked-by: Andy Lutomirski <luto@kernel.org> Acked-by: Frederic Weisbecker <frederic@kernel.org> Link: https://lkml.kernel.org/r/87wo4cxubv.fsf@nanos.tec.linutronix.de
Linus Torvalds [Fri, 12 Jun 2020 19:24:42 +0000 (12:24 -0700)]
Merge tag 'pwm/for-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm
Pull pwm updates from Thierry Reding:
"Nothing too exciting for this cycle. A couple of fixes across the
board, and Lee volunteered to help with patch review"
* tag 'pwm/for-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm:
pwm: Add missing "CONFIG_" prefix
MAINTAINERS: Add Lee Jones as reviewer for the PWM subsystem
pwm: imx27: Fix rounding behavior
pwm: rockchip: Simplify rockchip_pwm_get_state()
pwm: img: Call pm_runtime_put() in pm_runtime_get_sync() failed case
pwm: tegra: Support dynamic clock frequency configuration
pwm: jz4740: Add support for the JZ4725B
pwm: jz4740: Make PWM start with the active part
pwm: jz4740: Enhance precision in calculation of duty cycle
pwm: jz4740: Drop dependency on MACH_INGENIC
pwm: lpss: Fix get_state runtime-pm reference handling
pwm: sun4i: Support direct clock output on Allwinner A64
pwm: Add support for Azoteq IQS620A PWM generator
dt-bindings: pwm: rcar: add r8a77961 support
pwm: Add missing '\n' in log messages
Linus Torvalds [Fri, 12 Jun 2020 19:19:13 +0000 (12:19 -0700)]
Merge tag 'iommu-drivers-move-v5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu
Pull iommu driver directory structure cleanup from Joerg Roedel:
"Move the Intel and AMD IOMMU drivers into their own subdirectory.
Both drivers consist of several files by now and giving them their own
directory unclutters the IOMMU top-level directory a bit"
* tag 'iommu-drivers-move-v5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
iommu/vt-d: Move Intel IOMMU driver into subdirectory
iommu/amd: Move AMD IOMMU driver into subdirectory
Linus Torvalds [Fri, 12 Jun 2020 19:13:36 +0000 (12:13 -0700)]
Merge tag 'printk-for-5.8-kdb-nmi' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux
Pull printk fix from Petr Mladek:
"One more printk change for 5.8: make sure that messages printed from
KDB context are redirected to KDB console handlers. It did not work
when KDB interrupted NMI or printk_safe contexts.
Arm people started hitting this problem more often recently. I forgot
to add the fix into the previous pull request by mistake"
* tag 'printk-for-5.8-kdb-nmi' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
printk/kdb: Redirect printk messages into kdb in any context
projects / mirror_ubuntu-kernels.git / log