New xfeatures will not longer be automatically stored in the regular XSAVE
buffer in thread_struct::fpu.
The kernel will provide the default sized buffer for storing the regular
features up to AVX512 in thread_struct::fpu and if a task requests to use
one of the new features then the register storage has to be extended.
The state will be accessed via a pointer in thread_struct::fpu which
defaults to the builtin storage and can be switched when extended storage
is required.
To avoid conditionals all over the code, create a new container for the
register storage which will gain other information, e.g. size, feature
masks etc., later. For now it just contains the register storage, which
gives it exactly the same layout as the exiting fpu::state.
Stick fpu::state and the new fpu::__fpstate into an anonymous union and
initialize the pointer. Add build time checks to validate that both are
at the same place and have the same size.
This allows step by step conversion of all users.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211013145322.234458659@linutronix.de
I do not see panic calling rewind_stack_do_exit anywhere, nor can I
find anywhere in the history where doublefault_shim has called
rewind_stack_do_exit. So I don't think this comment was ever actually
correct.
Cc: Andy Lutomirski <luto@kernel.org>
Fixes: 7d8d8cfdee ("x86/doublefault/32: Rewrite the x86_32 #DF handler and unify with 64-bit")
Link: https://lkml.kernel.org/r/20211020174406.17889-1-ebiederm@xmission.com
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
internal.h is a kitchen sink which needs to get out of the way to prepare
for the upcoming changes.
Move the context switch and exit to user inlines into a separate header,
which is all that code needs.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211015011539.349132461@linutronix.de
Prepare for replacing the KVM copy xstate to user function by extending
copy_xstate_to_uabi_buf() with a pkru argument which allows the caller to
hand in the pkru value, which is required for KVM because the guest PKRU is
not accessible via current. Fixup all callsites accordingly.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211015011539.191902137@linutronix.de
Copying a user space buffer to the memory buffer is already available in
the FPU core. The copy mechanism in KVM lacks sanity checks and needs to
use cpuid() to lookup the offset of each component, while the FPU core has
this information cached.
Make the FPU core variant accessible for KVM and replace the home brewed
mechanism.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: kvm@vger.kernel.org
Link: https://lkml.kernel.org/r/20211015011539.134065207@linutronix.de
There is no reason why kernel and IO worker threads need a full clone of
the parent's FPU state. Both are kernel threads which are not supposed to
use FPU. So copying a large state or doing XSAVE() is pointless. Just clean
out the minimally required state for those tasks.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211015011538.839822981@linutronix.de
Zeroing the forked task's FPU registers buffer to avoid leaking init
optimized stale data into the clone is a pointless exercise for the case
where the current task has TIF_NEED_FPU_LOAD set. In that case, the FPU
registers state is copied from current's FPU register buffer which can
contain stale init optimized data as well.
The alledged information leak is non-existant because this stale init
optimized data is used nowhere and cannot leak anywhere.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211015011538.722854569@linutronix.de
Removing the fault protection code when writing return_hooker
to stack. As Steven noted:
> That protection was there from the beginning due to being "paranoid",
> considering ftrace was bricking network cards. But that protection
> would not have even protected against that.
Link: https://lkml.kernel.org/r/20211008091336.33616-3-jolsa@kernel.org
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Turn fault_in_pages_{readable,writeable} into versions that return the
number of bytes not faulted in, similar to copy_to_user, instead of
returning a non-zero value when any of the requested pages couldn't be
faulted in. This supports the existing users that require all pages to
be faulted in as well as new users that are happy if any pages can be
faulted in.
Rename the functions to fault_in_{readable,writeable} to make sure
this change doesn't silently break things.
Neither of these functions is entirely trivial and it doesn't seem
useful to inline them, so move them to mm/gup.c.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Struct pci_driver contains a struct device_driver, so for PCI devices, it's
easy to convert a device_driver * to a pci_driver * with to_pci_driver().
The device_driver * is in struct device, so we don't need to also keep
track of the pci_driver * in struct pci_dev.
Replace pdev->driver with to_pci_driver(). This is a step toward removing
pci_dev->driver.
[bhelgaas: split to separate patch]
Link: https://lore.kernel.org/r/20211004125935.2300113-11-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Resolve the conflict between these commits:
x86/fpu: 1193f408cd ("x86/fpu/signal: Change return type of __fpu_restore_sig() to boolean")
x86/urgent: d298b03506 ("x86/fpu: Restore the masking out of reserved MXCSR bits")
b2381acd3f ("x86/fpu: Mask out the invalid MXCSR bits properly")
Conflicts:
arch/x86/kernel/fpu/signal.c
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There are x86 CPU architectures (e.g. Jacobsville) where L2 cahce is
shared among a cluster of cores instead of being exclusive to one
single core.
To prevent oversubscription of L2 cache, load should be balanced
between such L2 clusters, especially for tasks with no shared data.
On benchmark such as SPECrate mcf test, this change provides a boost
to performance especially on medium load system on Jacobsville. on a
Jacobsville that has 24 Atom cores, arranged into 6 clusters of 4
cores each, the benchmark number is as follow:
Improvement over baseline kernel for mcf_r
copies run time base rate
1 -0.1% -0.2%
6 25.1% 25.1%
12 18.8% 19.0%
24 0.3% 0.3%
So this looks pretty good. In terms of the system's task distribution,
some pretty bad clumping can be seen for the vanilla kernel without
the L2 cluster domain for the 6 and 12 copies case. With the extra
domain for cluster, the load does get evened out between the clusters.
Note this patch isn't an universal win as spreading isn't necessarily
a win, particually for those workload who can benefit from packing.
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210924085104.44806-4-21cnbao@gmail.com
Currently, the kernel CONFIG_UNWINDER_ORC option is enabled by default
on x86, but the implementation of get_wchan() is still based on the frame
pointer unwinder, so the /proc/<pid>/wchan usually returned 0 regardless
of whether the task <pid> is running.
Reimplement get_wchan() by calling stack_trace_save_tsk(), which is
adapted to the ORC and frame pointer unwinders.
Fixes: ee9f8fce99 ("x86/unwind: Add the ORC unwinder")
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20211008111626.271115116@infradead.org
Pull x86 fixes from Borislav Petkov:
- A FPU fix to properly handle invalid MXCSR values: 32-bit masks them
out due to historical reasons and 64-bit kernels reject them
- A fix to clear X86_FEATURE_SMAP when support for is not
config-enabled
- Three fixes correcting misspelled Kconfig symbols used in code
- Two resctrl object cleanup fixes
- Yet another attempt at fixing the neverending saga of botched x86
timers, this time because some incredibly smart hardware decides to
turn off the HPET timer in a low power state - who cares if the OS is
relying on it...
- Check the full return value range of an SEV VMGEXIT call to determine
whether it returned an error
* tag 'x86_urgent_for_v5.15_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/fpu: Restore the masking out of reserved MXCSR bits
x86/Kconfig: Correct reference to MWINCHIP3D
x86/platform/olpc: Correct ifdef symbol to intended CONFIG_OLPC_XO15_SCI
x86/entry: Clear X86_FEATURE_SMAP when CONFIG_X86_SMAP=n
x86/entry: Correct reference to intended CONFIG_64_BIT
x86/resctrl: Fix kfree() of the wrong type in domain_add_cpu()
x86/resctrl: Free the ctrlval arrays when domain_setup_mon_state() fails
x86/hpet: Use another crystalball to evaluate HPET usability
x86/sev: Return an error on a returned non-zero SW_EXITINFO1[31:0]
Ser Olmy reported a boot failure:
init[1] bad frame in sigreturn frame:(ptrval) ip:b7c9fbe6 sp:bf933310 orax:ffffffff \
in libc-2.33.so[b7bed000+156000]
Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
CPU: 0 PID: 1 Comm: init Tainted: G W 5.14.9 #1
Hardware name: Hewlett-Packard HP PC/HP Board, BIOS JD.00.06 12/06/2001
Call Trace:
dump_stack_lvl
dump_stack
panic
do_exit.cold
do_group_exit
get_signal
arch_do_signal_or_restart
? force_sig_info_to_task
? force_sig
exit_to_user_mode_prepare
syscall_exit_to_user_mode
do_int80_syscall_32
entry_INT80_32
on an old 32-bit Intel CPU:
vendor_id : GenuineIntel
cpu family : 6
model : 6
model name : Celeron (Mendocino)
stepping : 5
microcode : 0x3
Ser bisected the problem to the commit in Fixes.
tglx suggested reverting the rejection of invalid MXCSR values which
this commit introduced and replacing it with what the old code did -
simply masking them out to zero.
Further debugging confirmed his suggestion:
fpu->state.fxsave.mxcsr: 0xb7be13b4, mxcsr_feature_mask: 0xffbf
WARNING: CPU: 0 PID: 1 at arch/x86/kernel/fpu/signal.c:384 __fpu_restore_sig+0x51f/0x540
so restore the original behavior only for 32-bit kernels where you have
ancient machines with buggy hardware. For 32-bit programs on 64-bit
kernels, user space which supplies wrong MXCSR values is considered
malicious so fail the sigframe restoration there.
Fixes: 6f9866a166 ("x86/fpu/signal: Let xrstor handle the features to init")
Reported-by: Ser Olmy <ser.olmy@protonmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Ser Olmy <ser.olmy@protonmail.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/YVtA67jImg3KlBTw@zn.tnic
Export smca_get_bank_type for use in the AMD GPU
driver to determine MCA bank while handling correctable
and uncorrectable errors in GPU UMC.
Signed-off-by: Mukul Joshi <mukul.joshi@amd.com>
Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
The size of the exception stacks was increased by the commit in Fixes,
resulting in stack sizes greater than a page in size. The #VC exception
handling was only mapping the first (bottom) page, resulting in an
SEV-ES guest failing to boot.
Make the #VC exception stacks part of the default exception stacks
storage and allocate them with a CONFIG_AMD_MEM_ENCRYPT=y .config. Map
them only when a SEV-ES guest has been detected.
Rip out the custom VC stacks mapping and storage code.
[ bp: Steal and adapt Tom's commit message. ]
Fixes: 7fae4c24a2 ("x86: Increase exception stack sizes")
Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Tom Lendacky <thomas.lendacky@amd.com>
Tested-by: Brijesh Singh <brijesh.singh@amd.com>
Link: https://lkml.kernel.org/r/YVt1IMjIs7pIZTRR@zn.tnic
