To support CONFIG_VMAP_STACK, the kernel has to activate Data MMU
Translation for accessing the stack. Before doing that it must save
SRR0, SRR1 and also DAR and DSISR when relevant, in order to not
loose them in case there is a Data TLB Miss once the translation is
reactivated.
This patch adds fields in thread struct for saving those registers.
It prepares entry_32.S to handle exception entry with
Data MMU Translation enabled and alters EXCEPTION_PROLOG macros to
save SRR0, SRR1, DAR and DSISR then reenables Data MMU.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/a775a1fea60f190e0f63503463fb775310a2009b.1576916812.git.christophe.leroy@c-s.fr
Commit a25bd72bad ("powerpc/mm/radix: Workaround prefetch issue with
KVM") introduced a number of workarounds as coming out of a guest with
the mmu enabled would make the cpu would start running in hypervisor
state with the PID value from the guest. The cpu will then start
prefetching for the hypervisor with that PID value.
In Power9 DD2.2 the cpu behaviour was modified to fix this. When
accessing Quadrant 0 in hypervisor mode with LPID != 0 prefetching will
not be performed. This means that we can get rid of the workarounds for
Power9 DD2.2 and later revisions. Add a new cpu feature
CPU_FTR_P9_RADIX_PREFETCH_BUG to indicate if the workarounds are needed.
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Acked-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191206031722.25781-1-jniethe5@gmail.com
Many drivers don't check for errors when they get a 0xFFs response from an
MMIO load. As a result after an EEH event occurs a driver can get stuck in
a polling loop unless it some kind of internal timeout logic.
Currently EEH tries to detect and report stuck drivers by dumping a stack
trace after eeh_dev_check_failure() is called EEH_MAX_FAILS times on an
already frozen PE. The value of EEH_MAX_FAILS was chosen so that a dump
would occur every few seconds if the driver was spinning in a loop. This
results in a lot of spurious stack traces in the kernel log.
Fix this by limiting it to printing one stack trace for each PE freeze. If
the driver is truely stuck the kernel's hung task detector is better suited
to reporting the probelm anyway.
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Sam Bobroff <sbobroff@linux.ibm.com>
Tested-by: Sam Bobroff <sbobroff@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191016012536.22588-1-oohall@gmail.com
The powerpc PCI code requires that a pci_dn structure exists for all
devices in the system. This is fine for real devices since at boot a pci_dn
is created for each PCI device in the DT and it's fine for hotplugged devices
since the hotplug slot driver will manage the pci_dn's devices in hotplug
slots. For SR-IOV, we need the platform / pcibios to manage the pci_dn for
virtual functions since firmware is unaware of VFs, and they aren't
"hot plugged" in the traditional sense.
Management of the pci_dn is handled by the, poorly named, functions:
add_pci_dev_data() and remove_pci_dev_data(). The entire body of these
functions is #ifdef`ed around CONFIG_PCI_IOV and they cannot be used
in any other context, so make them only available when CONFIG_PCI_IOV
is selected, and rename them to reflect their actual usage rather than
having them masquerade as generic code.
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Sam Bobroff <sbobroff@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190821062655.19735-2-oohall@gmail.com
When disabling virtual functions on an SR-IOV adapter we currently do not
correctly remove the EEH state for the now-dead virtual functions. When
removing the pci_dn that was created for the VF when SR-IOV was enabled
we free the corresponding eeh_dev without removing it from the child device
list of the eeh_pe that contained it. This can result in crashes due to the
use-after-free.
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Sam Bobroff <sbobroff@linux.ibm.com>
Tested-by: Sam Bobroff <sbobroff@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190821062655.19735-1-oohall@gmail.com
The eeh_sysfs_remove_device() function is supposed to clear the
EEH_DEV_SYSFS flag since it indicates the EEH sysfs entries have been added
for a pci_dev.
When the sysfs files are removed eeh_remove_device() the eeh_dev and the
pci_dev have already been de-associated. This then causes the
pci_dev_to_eeh_dev() call in eeh_sysfs_remove_device() to return NULL so
the flag can't be cleared from the still-live eeh_dev. This problem is
worked around in the caller by clearing the flag manually. However, this
behaviour doesn't make a whole lot of sense, so this patch fixes it by:
a) Re-ordering eeh_remove_device() so that eeh_sysfs_remove_device() is
called before de-associating the pci_dev and eeh_dev.
b) Making eeh_sysfs_remove_device() emit a warning if there's no
corresponding eeh_dev for a pci_dev. The paths where the sysfs
files are only reachable if EEH was setup for the device
for the device in the first place so hitting this warning
indicates a programming error.
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Sam Bobroff <sbobroff@linux.ibm.com>
Tested-by: Sam Bobroff <sbobroff@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190715085612.8802-6-oohall@gmail.com
There are several EEH sysfs properties that only exists when the
"ibm,is-open-sriov-pf" property appears in the device tree node of the PCI
device. This used on pseries to indicate to the guest that the hypervisor
allows the guest to configure the SR-IOV capability. Doing this requires
some handshaking between the guest, hypervisor and userspace when a VF is
EEH frozen which is why these properties exist.
This is all dead code on non-pseries platforms so wrap it in an #ifdef
CONFIG_PPC_PSERIES to make the dependency clearer.
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Tested-by: Sam Bobroff <sbobroff@linux.ibm.com>
Reviewed-by: Sam Bobroff <sbobroff@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190715085612.8802-4-oohall@gmail.com
__get_datapage() is only a few instructions to retrieve the
address of the page where the kernel stores data to the VDSO.
By inlining this function into its users, a bl/blr pair and
a mflr/mtlr pair is avoided, plus a few reg moves.
The improvement is noticeable (about 55 nsec/call on an 8xx)
vdsotest before the patch:
gettimeofday: vdso: 731 nsec/call
clock-gettime-realtime-coarse: vdso: 668 nsec/call
clock-gettime-monotonic-coarse: vdso: 745 nsec/call
vdsotest after the patch:
gettimeofday: vdso: 677 nsec/call
clock-gettime-realtime-coarse: vdso: 613 nsec/call
clock-gettime-monotonic-coarse: vdso: 690 nsec/call
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/c39ef7f3dfa25356b01e211d539671f279086c09.1575273217.git.christophe.leroy@c-s.fr
Commit 18ad51dd34 ("powerpc: Add VDSO version of getcpu") added
getcpu() for PPC64 only, by making use of a user readable general
purpose SPR.
PPC32 doesn't have any such SPR.
For non SMP, just return CPU id 0 from the VDSO directly.
PPC32 doesn't support CONFIG_NUMA so NUMA node is always 0.
Before the patch, vdsotest reported:
getcpu: syscall: 1572 nsec/call
getcpu: libc: 1787 nsec/call
getcpu: vdso: not tested
Now, vdsotest reports:
getcpu: syscall: 1582 nsec/call
getcpu: libc: 502 nsec/call
getcpu: vdso: 187 nsec/call
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/eaac4b6494ecff1811220fccc895bf282aab884a.1575273217.git.christophe.leroy@c-s.fr
Unlike standard powerpc, Powerpc 8xx doesn't have SPRN_DABR, but
it has a breakpoint support based on a set of comparators which
allow more flexibility.
Commit 4ad8622dc5 ("powerpc/8xx: Implement hw_breakpoint")
implemented breakpoints by emulating the DABR behaviour. It did
this by setting one comparator the match 4 bytes at breakpoint address
and the other comparator to match 4 bytes at breakpoint address + 4.
Rewrite 8xx hw_breakpoint to make breakpoints match all addresses
defined by the breakpoint address and length by making full use of
comparators.
Now, comparator E is set to match any address greater than breakpoint
address minus one. Comparator F is set to match any address lower than
breakpoint address plus breakpoint length. Addresses are aligned
to 32 bits.
When the breakpoint range starts at address 0, the breakpoint is set
to match comparator F only. When the breakpoint range end at address
0xffffffff, the breakpoint is set to match comparator E only.
Otherwise the breakpoint is set to match comparator E and F.
At the same time, use registers bit names instead of hardcoded values.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/05105deeaf63bc02151aea2cdeaf525534e0e9d4.1574790198.git.christophe.leroy@c-s.fr
/* Background. */
For a very long time, extending openat(2) with new features has been
incredibly frustrating. This stems from the fact that openat(2) is
possibly the most famous counter-example to the mantra "don't silently
accept garbage from userspace" -- it doesn't check whether unknown flags
are present[1].
This means that (generally) the addition of new flags to openat(2) has
been fraught with backwards-compatibility issues (O_TMPFILE has to be
defined as __O_TMPFILE|O_DIRECTORY|[O_RDWR or O_WRONLY] to ensure old
kernels gave errors, since it's insecure to silently ignore the
flag[2]). All new security-related flags therefore have a tough road to
being added to openat(2).
Userspace also has a hard time figuring out whether a particular flag is
supported on a particular kernel. While it is now possible with
contemporary kernels (thanks to [3]), older kernels will expose unknown
flag bits through fcntl(F_GETFL). Giving a clear -EINVAL during
openat(2) time matches modern syscall designs and is far more
fool-proof.
In addition, the newly-added path resolution restriction LOOKUP flags
(which we would like to expose to user-space) don't feel related to the
pre-existing O_* flag set -- they affect all components of path lookup.
We'd therefore like to add a new flag argument.
Adding a new syscall allows us to finally fix the flag-ignoring problem,
and we can make it extensible enough so that we will hopefully never
need an openat3(2).
/* Syscall Prototype. */
/*
* open_how is an extensible structure (similar in interface to
* clone3(2) or sched_setattr(2)). The size parameter must be set to
* sizeof(struct open_how), to allow for future extensions. All future
* extensions will be appended to open_how, with their zero value
* acting as a no-op default.
*/
struct open_how { /* ... */ };
int openat2(int dfd, const char *pathname,
struct open_how *how, size_t size);
/* Description. */
The initial version of 'struct open_how' contains the following fields:
flags
Used to specify openat(2)-style flags. However, any unknown flag
bits or otherwise incorrect flag combinations (like O_PATH|O_RDWR)
will result in -EINVAL. In addition, this field is 64-bits wide to
allow for more O_ flags than currently permitted with openat(2).
mode
The file mode for O_CREAT or O_TMPFILE.
Must be set to zero if flags does not contain O_CREAT or O_TMPFILE.
resolve
Restrict path resolution (in contrast to O_* flags they affect all
path components). The current set of flags are as follows (at the
moment, all of the RESOLVE_ flags are implemented as just passing
the corresponding LOOKUP_ flag).
RESOLVE_NO_XDEV => LOOKUP_NO_XDEV
RESOLVE_NO_SYMLINKS => LOOKUP_NO_SYMLINKS
RESOLVE_NO_MAGICLINKS => LOOKUP_NO_MAGICLINKS
RESOLVE_BENEATH => LOOKUP_BENEATH
RESOLVE_IN_ROOT => LOOKUP_IN_ROOT
open_how does not contain an embedded size field, because it is of
little benefit (userspace can figure out the kernel open_how size at
runtime fairly easily without it). It also only contains u64s (even
though ->mode arguably should be a u16) to avoid having padding fields
which are never used in the future.
Note that as a result of the new how->flags handling, O_PATH|O_TMPFILE
is no longer permitted for openat(2). As far as I can tell, this has
always been a bug and appears to not be used by userspace (and I've not
seen any problems on my machines by disallowing it). If it turns out
this breaks something, we can special-case it and only permit it for
openat(2) but not openat2(2).
After input from Florian Weimer, the new open_how and flag definitions
are inside a separate header from uapi/linux/fcntl.h, to avoid problems
that glibc has with importing that header.
/* Testing. */
In a follow-up patch there are over 200 selftests which ensure that this
syscall has the correct semantics and will correctly handle several
attack scenarios.
In addition, I've written a userspace library[4] which provides
convenient wrappers around openat2(RESOLVE_IN_ROOT) (this is necessary
because no other syscalls support RESOLVE_IN_ROOT, and thus lots of care
must be taken when using RESOLVE_IN_ROOT'd file descriptors with other
syscalls). During the development of this patch, I've run numerous
verification tests using libpathrs (showing that the API is reasonably
usable by userspace).
/* Future Work. */
Additional RESOLVE_ flags have been suggested during the review period.
These can be easily implemented separately (such as blocking auto-mount
during resolution).
Furthermore, there are some other proposed changes to the openat(2)
interface (the most obvious example is magic-link hardening[5]) which
would be a good opportunity to add a way for userspace to restrict how
O_PATH file descriptors can be re-opened.
Another possible avenue of future work would be some kind of
CHECK_FIELDS[6] flag which causes the kernel to indicate to userspace
which openat2(2) flags and fields are supported by the current kernel
(to avoid userspace having to go through several guesses to figure it
out).
[1]: https://lwn.net/Articles/588444/
[2]: https://lore.kernel.org/lkml/CA+55aFyyxJL1LyXZeBsf2ypriraj5ut1XkNDsunRBqgVjZU_6Q@mail.gmail.com
[3]: commit 629e014bb8 ("fs: completely ignore unknown open flags")
[4]: https://sourceware.org/bugzilla/show_bug.cgi?id=17523
[5]: https://lore.kernel.org/lkml/20190930183316.10190-2-cyphar@cyphar.com/
[6]: https://youtu.be/ggD-eb3yPVs
Suggested-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This implements the tricky tracing and soft irq handling bits in C,
leaving the low level bit to asm.
A functional difference is that this redirects the interrupt exit to
a return stub to execute blr, rather than the lr address itself. This
is probably barely measurable on real hardware, but it keeps the link
stack balanced.
Tested with QEMU.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Move power4_fixup_nap back into exceptions-64s.S]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190711022404.18132-1-npiggin@gmail.com
With the previous patch applied pcibios_setup_device() will always be run
when pcibios_bus_add_device() is called. There are several code paths where
pcibios_setup_bus_device() is still called (the PowerPC specific PCI
hotplug support is one) so with just the previous patch applied the setup
can be run multiple times on a device, once before the device is added
to the bus and once after.
There's no need to run the setup in the early case any more so just
remove it entirely.
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191028085424.12006-3-oohall@gmail.com
Move PCI device setup from pcibios_add_device() and pcibios_fixup_bus() to
pcibios_bus_add_device(). This ensures that platform-specific DMA and IOMMU
setup occurs after the device has been registered in sysfs, which is a
requirement for IOMMU group assignment to work
This fixes IOMMU group assignment for hotplugged devices on pseries, where
the existing behavior results in IOMMU assignment before registration.
Thanks to Lukas Wunner <lukas@wunner.de> for the suggestion.
Signed-off-by: Shawn Anastasio <shawn@anastas.io>
Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191028085424.12006-2-oohall@gmail.com
On pseries there is a bug with adding hotplugged devices to an IOMMU
group. For a number of dumb reasons fixing that bug first requires
re-working how VFs are configured on PowerNV. For background, on
PowerNV we use the pcibios_sriov_enable() hook to do two things:
1. Create a pci_dn structure for each of the VFs, and
2. Configure the PHB's internal BARs so the MMIO range for each VF
maps to a unique PE.
Roughly speaking a PE is the hardware counterpart to a Linux IOMMU
group since all the devices in a PE share the same IOMMU table. A PE
also defines the set of devices that should be isolated in response to
a PCI error (i.e. bad DMA, UR/CA, AER events, etc). When isolated all
MMIO and DMA traffic to and from devicein the PE is blocked by the
root complex until the PE is recovered by the OS.
The requirement to block MMIO causes a giant headache because the P8
PHB generally uses a fixed mapping between MMIO addresses and PEs. As
a result we need to delay configuring the IOMMU groups for device
until after MMIO resources are assigned. For physical devices (i.e.
non-VFs) the PE assignment is done in pcibios_setup_bridge() which is
called immediately after the MMIO resources for downstream
devices (and the bridge's windows) are assigned. For VFs the setup is
more complicated because:
a) pcibios_setup_bridge() is not called again when VFs are activated, and
b) The pci_dev for VFs are created by generic code which runs after
pcibios_sriov_enable() is called.
The work around for this is a two step process:
1. A fixup in pcibios_add_device() is used to initialised the cached
pe_number in pci_dn, then
2. A bus notifier then adds the device to the IOMMU group for the PE
specified in pci_dn->pe_number.
A side effect fixing the pseries bug mentioned in the first paragraph
is moving the fixup out of pcibios_add_device() and into
pcibios_bus_add_device(), which is called much later. This results in
step 2. failing because pci_dn->pe_number won't be initialised when
the bus notifier is run.
We can fix this by removing the need for the fixup. The PE for a VF is
known before the VF is even scanned so we can initialise
pci_dn->pe_number pcibios_sriov_enable() instead. Unfortunately,
moving the initialisation causes two problems:
1. We trip the WARN_ON() in the current fixup code, and
2. The EEH core clears pdn->pe_number when recovering a VF and
relies on the fixup to correctly re-set it.
The only justification for either of these is a comment in
eeh_rmv_device() suggesting that pdn->pe_number *must* be set to
IODA_INVALID_PE in order for the VF to be scanned. However, this
comment appears to have no basis in reality. Both bugs can be fixed by
just deleting the code.
Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191028085424.12006-1-oohall@gmail.com
The SUPPORT_SYSRQ ifdeffery is not nice as:
- May create misunderstanding about sizeof(struct uart_port) between
different objects
- Prevents moving functions from serial_core.h
- Reduces readability (well, it's ifdeffery - it's hard to follow)
In order to remove SUPPORT_SYSRQ, has_sysrq variable has been added.
Initialise it in driver's probe and remove ifdeffery.
In contrast to 8250/8250_of, legacy_serial on powerpc does fill
(struct plat_serial8250_port). The reason is likely that it's done on
device_initcall(), not on probe. So, 8250_core is not yet probed.
Propagate value from platform_device on 8250 probe - in case powepc
legacy driver it's initialized on initcall, in case 8250_of it will be
initialized later on of_platform_serial_setup().
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Dmitry Safonov <dima@arista.com>
Link: https://lore.kernel.org/r/20191213000657.931618-6-dima@arista.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull y2038 cleanups from Arnd Bergmann:
"y2038 syscall implementation cleanups
This is a series of cleanups for the y2038 work, mostly intended for
namespace cleaning: the kernel defines the traditional time_t, timeval
and timespec types that often lead to y2038-unsafe code. Even though
the unsafe usage is mostly gone from the kernel, having the types and
associated functions around means that we can still grow new users,
and that we may be missing conversions to safe types that actually
matter.
There are still a number of driver specific patches needed to get the
last users of these types removed, those have been submitted to the
respective maintainers"
Link: https://lore.kernel.org/lkml/20191108210236.1296047-1-arnd@arndb.de/
* tag 'y2038-cleanups-5.5' of git://git.kernel.org:/pub/scm/linux/kernel/git/arnd/playground: (26 commits)
y2038: alarm: fix half-second cut-off
y2038: ipc: fix x32 ABI breakage
y2038: fix typo in powerpc vdso "LOPART"
y2038: allow disabling time32 system calls
y2038: itimer: change implementation to timespec64
y2038: move itimer reset into itimer.c
y2038: use compat_{get,set}_itimer on alpha
y2038: itimer: compat handling to itimer.c
y2038: time: avoid timespec usage in settimeofday()
y2038: timerfd: Use timespec64 internally
y2038: elfcore: Use __kernel_old_timeval for process times
y2038: make ns_to_compat_timeval use __kernel_old_timeval
y2038: socket: use __kernel_old_timespec instead of timespec
y2038: socket: remove timespec reference in timestamping
y2038: syscalls: change remaining timeval to __kernel_old_timeval
y2038: rusage: use __kernel_old_timeval
y2038: uapi: change __kernel_time_t to __kernel_old_time_t
y2038: stat: avoid 'time_t' in 'struct stat'
y2038: ipc: remove __kernel_time_t reference from headers
y2038: vdso: powerpc: avoid timespec references
...
Pull powerpc updates from Michael Ellerman:
"Highlights:
- Infrastructure for secure boot on some bare metal Power9 machines.
The firmware support is still in development, so the code here
won't actually activate secure boot on any existing systems.
- A change to xmon (our crash handler / pseudo-debugger) to restrict
it to read-only mode when the kernel is lockdown'ed, otherwise it's
trivial to drop into xmon and modify kernel data, such as the
lockdown state.
- Support for KASLR on 32-bit BookE machines (Freescale / NXP).
- Fixes for our flush_icache_range() and __kernel_sync_dicache()
(VDSO) to work with memory ranges >4GB.
- Some reworks of the pseries CMM (Cooperative Memory Management)
driver to make it behave more like other balloon drivers and enable
some cleanups of generic mm code.
- A series of fixes to our hardware breakpoint support to properly
handle unaligned watchpoint addresses.
Plus a bunch of other smaller improvements, fixes and cleanups.
Thanks to: Alastair D'Silva, Andrew Donnellan, Aneesh Kumar K.V,
Anthony Steinhauser, Cédric Le Goater, Chris Packham, Chris Smart,
Christophe Leroy, Christopher M. Riedl, Christoph Hellwig, Claudio
Carvalho, Daniel Axtens, David Hildenbrand, Deb McLemore, Diana
Craciun, Eric Richter, Geert Uytterhoeven, Greg Kroah-Hartman, Greg
Kurz, Gustavo L. F. Walbon, Hari Bathini, Harish, Jason Yan, Krzysztof
Kozlowski, Leonardo Bras, Mathieu Malaterre, Mauro S. M. Rodrigues,
Michal Suchanek, Mimi Zohar, Nathan Chancellor, Nathan Lynch, Nayna
Jain, Nick Desaulniers, Oliver O'Halloran, Qian Cai, Rasmus Villemoes,
Ravi Bangoria, Sam Bobroff, Santosh Sivaraj, Scott Wood, Thomas Huth,
Tyrel Datwyler, Vaibhav Jain, Valentin Longchamp, YueHaibing"
* tag 'powerpc-5.5-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (144 commits)
powerpc/fixmap: fix crash with HIGHMEM
x86/efi: remove unused variables
powerpc: Define arch_is_kernel_initmem_freed() for lockdep
powerpc/prom_init: Use -ffreestanding to avoid a reference to bcmp
powerpc: Avoid clang warnings around setjmp and longjmp
powerpc: Don't add -mabi= flags when building with Clang
powerpc: Fix Kconfig indentation
powerpc/fixmap: don't clear fixmap area in paging_init()
selftests/powerpc: spectre_v2 test must be built 64-bit
powerpc/powernv: Disable native PCIe port management
powerpc/kexec: Move kexec files into a dedicated subdir.
powerpc/32: Split kexec low level code out of misc_32.S
powerpc/sysdev: drop simple gpio
powerpc/83xx: map IMMR with a BAT.
powerpc/32s: automatically allocate BAT in setbat()
powerpc/ioremap: warn on early use of ioremap()
powerpc: Add support for GENERIC_EARLY_IOREMAP
powerpc/fixmap: Use __fix_to_virt() instead of fix_to_virt()
powerpc/8xx: use the fixmapped IMMR in cpm_reset()
powerpc/8xx: add __init to cpm1 init functions
...
Pull powerpc Spectre-RSB fixes from Michael Ellerman:
"We failed to activate the mitigation for Spectre-RSB (Return Stack
Buffer, aka. ret2spec) on context switch, on CPUs prior to Power9
DD2.3.
That allows a process to poison the RSB (called Link Stack on Power
CPUs) and possibly misdirect speculative execution of another process.
If the victim process can be induced to execute a leak gadget then it
may be possible to extract information from the victim via a side
channel.
The fix is to correctly activate the link stack flush mitigation on
all CPUs that have any mitigation of Spectre v2 in userspace enabled.
There's a second commit which adds a link stack flush in the KVM guest
exit path. A leak via that path has not been demonstrated, but we
believe it's at least theoretically possible.
This is the fix for CVE-2019-18660"
* tag 'powerpc-spectre-rsb' of /home/torvalds/Downloads/powerpc-CVE-2019-18660.bundle:
KVM: PPC: Book3S HV: Flush link stack on guest exit to host kernel
powerpc/book3s64: Fix link stack flush on context switch
Pull scheduler updates from Ingo Molnar:
"The biggest changes in this cycle were:
- Make kcpustat vtime aware (Frederic Weisbecker)
- Rework the CFS load_balance() logic (Vincent Guittot)
- Misc cleanups, smaller enhancements, fixes.
The load-balancing rework is the most intrusive change: it replaces
the old heuristics that have become less meaningful after the
introduction of the PELT metrics, with a grounds-up load-balancing
algorithm.
As such it's not really an iterative series, but replaces the old
load-balancing logic with the new one. We hope there are no
performance regressions left - but statistically it's highly probable
that there *is* going to be some workload that is hurting from these
chnages. If so then we'd prefer to have a look at that workload and
fix its scheduling, instead of reverting the changes"
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (46 commits)
rackmeter: Use vtime aware kcpustat accessor
leds: Use all-in-one vtime aware kcpustat accessor
cpufreq: Use vtime aware kcpustat accessors for user time
procfs: Use all-in-one vtime aware kcpustat accessor
sched/vtime: Bring up complete kcpustat accessor
sched/cputime: Support other fields on kcpustat_field()
sched/cpufreq: Move the cfs_rq_util_change() call to cpufreq_update_util()
sched/fair: Add comments for group_type and balancing at SD_NUMA level
sched/fair: Fix rework of find_idlest_group()
sched/uclamp: Fix overzealous type replacement
sched/Kconfig: Fix spelling mistake in user-visible help text
sched/core: Further clarify sched_class::set_next_task()
sched/fair: Use mul_u32_u32()
sched/core: Simplify sched_class::pick_next_task()
sched/core: Optimize pick_next_task()
sched/core: Make pick_next_task_idle() more consistent
sched/fair: Better document newidle_balance()
leds: Use vtime aware kcpustat accessor to fetch CPUTIME_SYSTEM
cpufreq: Use vtime aware kcpustat accessor to fetch CPUTIME_SYSTEM
procfs: Use vtime aware kcpustat accessor to fetch CPUTIME_SYSTEM
...
Pull x86 asm updates from Ingo Molnar:
"The main changes in this cycle were:
- Cross-arch changes to move the linker sections for NOTES and
EXCEPTION_TABLE into the RO_DATA area, where they belong on most
architectures. (Kees Cook)
- Switch the x86 linker fill byte from x90 (NOP) to 0xcc (INT3), to
trap jumps into the middle of those padding areas instead of
sliding execution. (Kees Cook)
- A thorough cleanup of symbol definitions within x86 assembler code.
The rather randomly named macros got streamlined around a
(hopefully) straightforward naming scheme:
SYM_START(name, linkage, align...)
SYM_END(name, sym_type)
SYM_FUNC_START(name)
SYM_FUNC_END(name)
SYM_CODE_START(name)
SYM_CODE_END(name)
SYM_DATA_START(name)
SYM_DATA_END(name)
etc - with about three times of these basic primitives with some
label, local symbol or attribute variant, expressed via postfixes.
No change in functionality intended. (Jiri Slaby)
- Misc other changes, cleanups and smaller fixes"
* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (67 commits)
x86/entry/64: Remove pointless jump in paranoid_exit
x86/entry/32: Remove unused resume_userspace label
x86/build/vdso: Remove meaningless CFLAGS_REMOVE_*.o
m68k: Convert missed RODATA to RO_DATA
x86/vmlinux: Use INT3 instead of NOP for linker fill bytes
x86/mm: Report actual image regions in /proc/iomem
x86/mm: Report which part of kernel image is freed
x86/mm: Remove redundant address-of operators on addresses
xtensa: Move EXCEPTION_TABLE to RO_DATA segment
powerpc: Move EXCEPTION_TABLE to RO_DATA segment
parisc: Move EXCEPTION_TABLE to RO_DATA segment
microblaze: Move EXCEPTION_TABLE to RO_DATA segment
ia64: Move EXCEPTION_TABLE to RO_DATA segment
h8300: Move EXCEPTION_TABLE to RO_DATA segment
c6x: Move EXCEPTION_TABLE to RO_DATA segment
arm64: Move EXCEPTION_TABLE to RO_DATA segment
alpha: Move EXCEPTION_TABLE to RO_DATA segment
x86/vmlinux: Move EXCEPTION_TABLE to RO_DATA segment
x86/vmlinux: Actually use _etext for the end of the text segment
vmlinux.lds.h: Allow EXCEPTION_TABLE to live in RO_DATA
...
LLVM revision r374662 gives LLVM the ability to convert certain loops
into a reference to bcmp as an optimization; this breaks
prom_init_check.sh:
CALL arch/powerpc/kernel/prom_init_check.sh
Error: External symbol 'bcmp' referenced from prom_init.c
make[2]: *** [arch/powerpc/kernel/Makefile:196: prom_init_check] Error 1
bcmp is defined in lib/string.c as a wrapper for memcmp so this could
be added to the whitelist. However, commit
450e7dd400 ("powerpc/prom_init: don't use string functions from
lib/") copied memcmp as prom_memcmp to avoid KASAN instrumentation so
having bcmp be resolved to regular memcmp would break that assumption.
Furthermore, because the compiler is the one that inserted bcmp, we
cannot provide something like prom_bcmp.
To prevent LLVM from being clever with optimizations like this, use
-ffreestanding to tell LLVM we are not hosted so it is not free to
make transformations like this.
Reviewed-by: Nick Desaulneris <ndesaulniers@google.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191119045712.39633-4-natechancellor@gmail.com
