When a kernel is built without CONFIG_ARM64_MODULE_PLTS, we don't
generate the expected branch instruction in ftrace_make_nop(). This
means we pass zero (rather than a valid branch) to ftrace_modify_code()
as the expected instruction to validate. This causes us to return
-EINVAL to the core ftrace code for a valid case, resulting in a splat
at boot time.

This was an unintended effect of commit:

  68764420 ("arm64: ftrace: fix building without CONFIG_MODULES")

... which incorrectly moved the generation of the branch instruction
into the ifdef for CONFIG_ARM64_MODULE_PLTS.

This patch fixes the issue by moving the ifdef inside of the relevant
if-else case, and always checking that the branch is in range,
regardless of CONFIG_ARM64_MODULE_PLTS. This ensures that we generate
the expected branch instruction, and also improves our sanity checks.

For consistency, both ftrace_make_nop() and ftrace_make_call() are
updated with this pattern.

Fixes: 68764420 ("arm64: ftrace: fix building without CONFIG_MODULES")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reported-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

This patch defines an extra_context signal frame record that can be
used to describe an expanded signal frame, and modifies the context
block allocator and signal frame setup and parsing code to create,
populate, parse and decode this block as necessary.

To avoid abuse by userspace, parse_user_sigframe() attempts to
ensure that:

 * no more than one extra_context is accepted;
 * the extra context data is a sensible size, and properly placed
   and aligned.

The extra_context data is required to start at the first 16-byte
aligned address immediately after the dummy terminator record
following extra_context in rt_sigframe.__reserved[] (as ensured
during signal delivery).  This serves as a sanity-check that the
signal frame has not been moved or copied without taking the extra
data into account.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
[will: add __force annotation when casting extra_datap to __user pointer]
Signed-off-by: Will Deacon <will.deacon@arm.com>

When debugging a kernel panic(), it can be useful to know which CPU
features have been detected by the kernel, as some code paths can depend
on these (and may have been patched at runtime).

This patch adds a notifier to dump the detected CPU caps (as a hex
string) at panic(), when we log other information useful for debugging.
On a Juno R1 system running v4.12-rc5, this looks like:

[  615.431249] Kernel panic - not syncing: Fatal exception in interrupt
[  615.437609] SMP: stopping secondary CPUs
[  615.441872] Kernel Offset: disabled
[  615.445372] CPU features: 0x02086
[  615.448522] Memory Limit: none

A developer can decode this by looking at the corresponding
<asm/cpucaps.h> bits. For example, the above decodes as:

* bit  1: ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE
* bit  2: ARM64_WORKAROUND_845719
* bit  7: ARM64_WORKAROUND_834220
* bit 13: ARM64_HAS_32BIT_EL0
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Steve Capper <steve.capper@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

When reading current's user-writable TLS register (which occurs
when dumping core for native tasks), it is possible that userspace
has modified it since the time the task was last scheduled out.
The new TLS register value is not guaranteed to have been written
immediately back to thread_struct in this case.

As a result, a coredump can capture stale data for this register.
Reading the register for a stopped task via ptrace is unaffected.

For native tasks, this patch explicitly flushes the TPIDR_EL0
register back to thread_struct before dumping when operating on
current, thus ensuring that coredump contents are up to date.  For
compat tasks, the TLS register is not user-writable and so cannot
be out of sync, so no flush is required in compat_tls_get().
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

When reading the FPSIMD state of current (which occurs when dumping
core), it is possible that userspace has modified the FPSIMD
registers since the time the task was last scheduled out.  Such
changes are not guaranteed to be reflected immedately in
thread_struct.

As a result, a coredump can contain stale values for these
registers.  Reading the registers of a stopped task via ptrace is
unaffected.

This patch explicitly flushes the CPU state back to thread_struct
before dumping when operating on current, thus ensuring that
coredump contents are up to date.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Currently, VFP registers are omitted from coredumps for compat
processes, due to a bug in the REGSET_COMPAT_VFP regset
implementation.

compat_vfp_get() needs to transfer non-contiguous data from
thread_struct.fpsimd_state, and uses put_user() to handle the
offending trailing word (FPSCR).  This fails when copying to a
kernel address (i.e., kbuf && !ubuf), which is what happens when
dumping core.  As a result, the ELF coredump core code silently
omits the NT_ARM_VFP note from the dump.

It would be possible to work around this with additional special
case code for the put_user(), but since user_regset_copyout() is
explicitly designed to handle this scenario it is cleaner to port
the put_user() to a user_regset_copyout() call, which this patch
does.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

When using sparse on the arm64 tree we get many thousands of
warnings like 'constant ... is so big it is unsigned long long'
or 'shift too big (32) for type unsigned long'. This happens
because by default sparse considers the machine as 32bit and
defines the size of the types accordingly.

Fix this by passing the '-m64' flag to sparse so that
sparse can correctly define longs as being 64bit.

CC: Catalin Marinas <catalin.marinas@arm.com>
CC: Will Deacon <will.deacon@arm.com>
CC: linux-arm-kernel@lists.infradead.org
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

This patch factors out the allocator for signal frame optional
records into a separate function, to ensure consistency and
facilitate later expansion.

No overrun checking is currently done, because the allocation is in
user memory and anyway the kernel never tries to allocate enough
space in the signal frame yet for an overrun to occur.  This
behaviour will be refined in future patches.

The approach taken in this patch to allocation of the terminator
record is not very clean: this will also be replaced in subsequent
patches.

For future extension, a comment is added in sigcontext.h
documenting the current static allocations in __reserved[].  This
will be important for determining under what circumstances
userspace may or may not see an expanded signal frame.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

In preparation for expanding the signal frame, this patch refactors
the signal frame setup code in setup_sigframe() into two separate
passes.

The first pass, setup_sigframe_layout(), determines the size of the
signal frame and its internal layout, including the presence and
location of optional records.  The resulting knowledge is used to
allocate and locate the user stack space required for the signal
frame and to determine which optional records to include.

The second pass, setup_sigframe(), is called once the stack frame
is allocated in order to populate it with the necessary context
information.

As a result of these changes, it becomes more natural to represent
locations in the signal frame by a base pointer and an offset,
since the absolute address of each location is not known during the
layout pass.  To be more consistent with this logic,
parse_user_sigframe() is refactored to describe signal frame
locations in a similar way.

This change has no effect on the signal ABI, but will make it
easier to expand the signal frame in future patches.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Currently, rt_sigreturn does very limited checking on the
sigcontext coming from userspace.

Future additions to the sigcontext data will increase the potential
for surprises.  Also, it is not clear whether the sigcontext
extension records are supposed to occur in a particular order.

To allow the parsing code to be extended more easily, this patch
factors out the sigcontext parsing into a separate function, and
adds extra checks to validate the well-formedness of the sigcontext
structure.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

In order to be able to increase the amount of the data currently
written to the __reserved[] array in the signal frame, it is
necessary to overwrite the locations currently occupied by the
{fp,lr} frame link record pushed at the top of the signal stack.

In order for this to work, this patch detaches the frame link
record from struct rt_sigframe and places it separately at the top
of the signal stack.  This will allow subsequent patches to insert
data between it and __reserved[].

This change relies on the non-ABI status of the placement of the
frame record with respect to struct sigframe: this status is
undocumented, but the placement is not declared or described in the
user headers, and known unwinder implementations (libgcc,
libunwind, gdb) appear not to rely on it.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

To avoid issues with the /proc/kcore code getting confused about the
kernels block mappings in the VMALLOC region, enable the existing
facility that describes the [_text, _end) interval as a separate
KCORE_TEXT region, which supersedes the KCORE_VMALLOC region that
it intersects with on arm64.
Reported-by: Tan Xiaojun <tanxiaojun@huawei.com>
Tested-by: Tan Xiaojun <tanxiaojun@huawei.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Laura Abbott <labbott@redhat.com>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Instead of passing each start address into is_vmalloc_or_module_addr()
to decide whether it falls into either the VMALLOC or the MODULES region,
we can simply check the type field of the current kcore_list entry, since
it will be set to KCORE_VMALLOC based on exactly the same conditions.

As a bonus, when reading the KCORE_TEXT region on architectures that have
one, this will avoid using vread() on the region if it happens to intersect
with a KCORE_VMALLOC region. This is due the fact that the KCORE_TEXT
region is the first one to be added to the kcore region list.
Reported-by: Tan Xiaojun <tanxiaojun@huawei.com>
Tested-by: Tan Xiaojun <tanxiaojun@huawei.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Laura Abbott <labbott@redhat.com>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

As it turns out, arm64 deviates from other architectures in the way it
maps the VMALLOC region: on most (all?) other architectures, it resides
strictly above the kernel's direct mapping of DRAM, but on arm64, this
is the other way around. For instance, for a 48-bit VA configuration,
we have

  modules : 0xffff000000000000 - 0xffff000008000000   (   128 MB)
  vmalloc : 0xffff000008000000 - 0xffff7dffbfff0000   (129022 GB)
  ...
  vmemmap : 0xffff7e0000000000 - 0xffff800000000000   (  2048 GB maximum)
            0xffff7e0000000000 - 0xffff7e0003ff0000   (    63 MB actual)
  memory  : 0xffff800000000000 - 0xffff8000ffc00000   (  4092 MB)

This has mostly gone unnoticed until now, but it does appear that it
breaks an assumption in the kmem read/write code, which does something
like

  if (p < (unsigned long) high_memory) {
    ... use straight copy_[to|from]_user() using p as virtual address ...
  }
  ...
  if (count > 0) {
    ... use vread/vwrite for accesses past high_memory ...
  }

The first condition will inadvertently hold for the VMALLOC region if
VMALLOC_START < PAGE_OFFSET [which is the case on arm64], but the read
or write will subsequently fail the virt_addr_valid() check, resulting
in a -ENXIO return value.

Given how kmem seems to be living in borrowed time anyway, and given
the fact that nobody noticed that the read/write interface is broken
on arm64 in the first place, let's not bother trying to fix it, but
simply disable the /dev/kmem interface entirely for arm64.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

The kernel watchdog is a great debugging tool for finding tasks that
consume a disproportionate amount of CPU time in contiguous chunks. One
can imagine building a similar watchdog for arbitrary driver threads
using save_stack_trace_tsk() and print_stack_trace(). However, this is
not viable for dynamically loaded driver modules on ARM platforms
because save_stack_trace_tsk() is not exported for those architectures.
Export save_stack_trace_tsk() for the ARM64 architecture to align with
x86 and support various debugging use cases such as arbitrary driver
thread watchdog timers.
Signed-off-by: Dustin Brown <dustinb@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Commit 316ca880 ("ACPI/IORT: Remove linker section for IORT entries
probing") removed the linker section for IORT entries probing.

Since those IORT entries were the only iort_node_match() interface
users, the iort_node_match() became obsolete and can then be removed.

Remove the ACPI IORT iort_node_match() interface from the kernel.
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

ACPI IORT is an ACPI addendum to describe the connection topology of
devices with IOMMUs and interrupt controllers on ARM64 ACPI systems.

Currently the ACPI IORT Kbuild symbol is selected whenever the Kbuild
symbol ARM_GIC_V3_ITS is enabled, which in turn is selected by ARM64
Kbuild defaults. This makes the logic behind ACPI_IORT selection a bit
twisted and not easy to follow. On ARM64 systems enabling ACPI the
kbuild symbol ACPI_IORT should always be selected in that it is a kernel
layer provided to the ARM64 arch code to parse and enable ACPI firmware
bindings.

Make the ACPI_IORT selection explicit in ARM64 Kbuild and remove the
selection from ARM_GIC_V3_ITS entry, making the ACPI_IORT selection
logic clearer to follow.
Acked-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

The current null-pointer check in __dma_alloc_coherent and
__dma_free_coherent is not needed anymore since the
__dma_alloc/__dma_free functions won't be called if !dev (dummy ops will
be called instead).
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Declare ARCH_SUPPORTS_MEMORY_FAILURE, as arm64 does support
memory failure recovery attempt.
Signed-off-by: Jonathan (Zhixiong) Zhang <zjzhang@codeaurora.org>
Signed-off-by: Tyler Baicar <tbaicar@codeaurora.org>
(Dropped changes to ACPI APEI Kconfig and updated commit log)
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Acked-by: Steve Capper <steve.capper@arm.com>
Tested-by: Manoj Iyer <manoj.iyer@canonical.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Re-organise the perf accounting for fault handling in preparation for
enabling handling of hardware poison faults in subsequent commits. The
change updates perf accounting to be inline with the behaviour on
x86.

With this update, the perf fault accounting -

  * Always report PERF_COUNT_SW_PAGE_FAULTS

  * Doesn't report anything else for VM_FAULT_ERROR (which includes
    hwpoison faults)

  * Reports PERF_COUNT_SW_PAGE_FAULTS_MAJ if it's a major
    fault (indicated by VM_FAULT_MAJOR)

  * Otherwise, reports PERF_COUNT_SW_PAGE_FAULTS_MIN
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Add VM_FAULT_HWPOISON[_LARGE] handling to the arm64 page fault
handler. Handling of VM_FAULT_HWPOISON[_LARGE] is very similar
to VM_FAULT_OOM, the only difference is that a different si_code
(BUS_MCEERR_AR) is passed to user space and si_addr_lsb field is
initialized.
Signed-off-by: Jonathan (Zhixiong) Zhang <zjzhang@codeaurora.org>
Signed-off-by: Tyler Baicar <tbaicar@codeaurora.org>
(fix new __do_user_fault call-site)
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Acked-by: Steve Capper <steve.capper@arm.com>
Tested-by: Manoj Iyer <manoj.iyer@canonical.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

When memory failure is enabled, a poisoned hugepage pte is marked as a
swap entry. huge_pte_offset() does not return the poisoned page table
entries when it encounters PUD/PMD hugepages.

This behaviour of huge_pte_offset() leads to error such as below when
munmap is called on poisoned hugepages.

[  344.165544] mm/pgtable-generic.c:33: bad pmd 000000083af00074.

Fix huge_pte_offset() to return the poisoned pte which is then
appropriately handled by the generic layer code.
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Acked-by: Steve Capper <steve.capper@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Woods <dwoods@mellanox.com>
Tested-by: Manoj Iyer <manoj.iyer@canonical.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

When CONFIG_MODULES is disabled, we cannot dereference a module pointer:

arch/arm64/kernel/ftrace.c: In function 'ftrace_make_call':
arch/arm64/kernel/ftrace.c:107:36: error: dereferencing pointer to incomplete type 'struct module'
   trampoline = (unsigned long *)mod->arch.ftrace_trampoline;

Also, the within_module() function is not defined:

arch/arm64/kernel/ftrace.c: In function 'ftrace_make_nop':
arch/arm64/kernel/ftrace.c:171:8: error: implicit declaration of function 'within_module'; did you mean 'init_module'? [-Werror=implicit-function-declaration]

This addresses both by adding replacing the IS_ENABLED(CONFIG_ARM64_MODULE_PLTS)
checks with #ifdef versions.

Fixes: e71a4e1b ("arm64: ftrace: add support for far branches to dynamic ftrace")
Reported-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Whilst debugging a remote crash, I noticed that show_pte is unhelpful
when it comes to describing the structure of the page table being walked.
This is easily fixed by printing out the page table (swapper vs user),
page size and virtual address size when displaying the PGD address.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Print out the name of the file associated with the vma that faulted.
This is usually the executable or shared library name. We already print
out the task name, but also printing the library name is useful for
pinpointing bugs to libraries.

Also print the base address and size of the vma, which together with the
PC (printed by __show_regs) gives the offset into the library.

Fault prints now look like:
test[2361]: unhandled level 2 translation fault (11) at 0x00000012, esr 0x92000006, in libfoo.so[ffffa0145000+1000]

This is already done on x86, for more details see commit 03252919
("x86: print which shared library/executable faulted in segfault etc.
messages v3").
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

When we take a fault from EL0 that can't be handled, we print out the
page table entries associated with the faulting address. This allows
userspace to print out any current page table entries, including kernel
(TTBR1) entries. Exposing kernel mappings like this could pose a
security risk, so don't print out page table information on EL0 faults.
(But still print it out for EL1 faults.) This also follows the same
behaviour as x86, printing out page table entries on kernel mode faults
but not user mode faults.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

When we take a fault that can't be handled, we print out the page table
entries associated with the faulting address. In some cases we currently
print out the wrong entries. For a faulting TTBR1 address, we sometimes
print out TTBR0 table entries instead, and for a faulting TTBR0 address
we sometimes print out TTBR1 table entries. Fix this by choosing the
tables based on the faulting address.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com>
[will: zero-extend addrs to 64-bit, don't walk swapper w/ TTBR0 addr]
Signed-off-by: Will Deacon <will.deacon@arm.com>

Currently, dynamic ftrace support in the arm64 kernel assumes that all
core kernel code is within range of ordinary branch instructions that
occur in module code, which is usually the case, but is no longer
guaranteed now that we have support for module PLTs and address space
randomization.

Since on arm64, all patching of branch instructions involves function
calls to the same entry point [ftrace_caller()], we can emit the modules
with a trampoline that has unlimited range, and patch both the trampoline
itself and the branch instruction to redirect the call via the trampoline.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
[will: minor clarification to smp_wmb() comment]
Signed-off-by: Will Deacon <will.deacon@arm.com>

When turning branch instructions into NOPs, we attempt to validate the
action by comparing the old value at the call site with the opcode of
a direct relative branch instruction pointing at the old target.

However, these call sites are statically initialized to call _mcount(),
and may be redirected via a PLT entry if the module is loaded far away
from the kernel text, leading to false negatives and spurious errors.

So skip the validation if CONFIG_ARM64_MODULE_PLTS is configured.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Adjust vdso_{start|end} to be char arrays to avoid compile-time analysis
that flags "too large" memcmp() calls with CONFIG_FORTIFY_SOURCE.

Cc: Jisheng Zhang <jszhang@marvell.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Suggested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Commit 3fde2999 ("arm64: cpufeature: Don't dump useless backtrace on
CPU_OUT_OF_SPEC") changed the cpufeature detection code to use add_taint
instead of WARN_TAINT_ONCE when detecting a heterogeneous system with
mismatched feature support. Unfortunately, this resulted in all systems
getting the taint, regardless of any feature mismatch.

This patch fixes the problem by conditionalising the taint on detecting
a feature mismatch.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Reported-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

When running lscpu on an AArch64 system that has SMBIOS version 2.0
tables, it will segfault in the following way:

  Unable to handle kernel paging request at virtual address ffff8000bfff0000
  pgd = ffff8000f9615000
  [ffff8000bfff0000] *pgd=0000000000000000
  Internal error: Oops: 96000007 [#1] PREEMPT SMP
  Modules linked in:
  CPU: 0 PID: 1284 Comm: lscpu Not tainted 4.11.0-rc3+ #103
  Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015
  task: ffff8000fa78e800 task.stack: ffff8000f9780000
  PC is at __arch_copy_to_user+0x90/0x220
  LR is at read_mem+0xcc/0x140

This is caused by the fact that lspci issues a read() on /dev/mem at the
offset where it expects to find the SMBIOS structure array. However, this
region is classified as EFI_RUNTIME_SERVICE_DATA (as per the UEFI spec),
and so it is omitted from the linear mapping.

So let's restrict /dev/mem read/write access to those areas that are
covered by the linear region.
Reported-by: Alexander Graf <agraf@suse.de>
Fixes: 4dffbfc4 ("arm64/efi: mark UEFI reserved regions as MEMBLOCK_NOMAP")
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

PCI core requires the NUMA node for the struct pci_host_bridge.dev to
be set by using the pcibus_to_node(struct pci_bus*) API, that on ARM64
systems relies on the struct pci_host_bridge->bus.dev NUMA node.

The struct pci_host_bridge.dev NUMA node is then propagated through
the PCI device hierarchy as PCI devices (and bridges) are enumerated
under it.

Therefore, in order to set-up the PCI NUMA hierarchy appropriately, the
struct pci_host_bridge->bus.dev NUMA node must be set before core
code calls pcibus_to_node(struct pci_bus*) on it so that PCI core can
retrieve the NUMA node for the struct pci_host_bridge.dev device and can
propagate it through the PCI bus tree.

On ARM64 ACPI based systems the struct pci_host_bridge->bus.dev NUMA
node can be set-up in pcibios_root_bridge_prepare() by parsing the root
bridge ACPI device firmware binding.

Add code to the pcibios_root_bridge_prepare() that, when booting with
ACPI, parse the root bridge ACPI device companion NUMA binding and set
the corresponding struct pci_host_bridge->bus.dev NUMA node
appropriately.

Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Robert Richter <rrichter@cavium.com>
Tested-by: Robert Richter <rrichter@cavium.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

FUTEX_OP_OPARG_SHIFT instructs the futex code to treat the 12-bit oparg
field as a shift value, potentially leading to a left shift value that
is negative or with an absolute value that is significantly larger then
the size of the type. UBSAN chokes with:

================================================================================
UBSAN: Undefined behaviour in ./arch/arm64/include/asm/futex.h:60:13
shift exponent -1 is negative
CPU: 1 PID: 1449 Comm: syz-executor0 Not tainted 4.11.0-rc4-00005-g977eb52-dirty #11
Hardware name: linux,dummy-virt (DT)
Call trace:
[<ffff200008094778>] dump_backtrace+0x0/0x538 arch/arm64/kernel/traps.c:73
[<ffff200008094cd0>] show_stack+0x20/0x30 arch/arm64/kernel/traps.c:228
[<ffff200008c194a8>] __dump_stack lib/dump_stack.c:16 [inline]
[<ffff200008c194a8>] dump_stack+0x120/0x188 lib/dump_stack.c:52
[<ffff200008cc24b8>] ubsan_epilogue+0x18/0x98 lib/ubsan.c:164
[<ffff200008cc3098>] __ubsan_handle_shift_out_of_bounds+0x250/0x294 lib/ubsan.c:421
[<ffff20000832002c>] futex_atomic_op_inuser arch/arm64/include/asm/futex.h:60 [inline]
[<ffff20000832002c>] futex_wake_op kernel/futex.c:1489 [inline]
[<ffff20000832002c>] do_futex+0x137c/0x1740 kernel/futex.c:3231
[<ffff200008320504>] SYSC_futex kernel/futex.c:3281 [inline]
[<ffff200008320504>] SyS_futex+0x114/0x268 kernel/futex.c:3249
[<ffff200008084770>] el0_svc_naked+0x24/0x28
================================================================================
syz-executor1 uses obsolete (PF_INET,SOCK_PACKET)
sock: process `syz-executor0' is using obsolete setsockopt SO_BSDCOMPAT

This patch attempts to fix some of this by:

  * Making encoded_op an unsigned type, so we can shift it left even if
    the top bit is set.

  * Casting to signed prior to shifting right when extracting oparg
    and cmparg

  * Consider only the bottom 5 bits of oparg when using it as a left-shift
    value.

Whilst I think this catches all of the issues, I'd much prefer to remove
this stuff, as I think it's unused and the bugs are copy-pasted between
a bunch of architectures.
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

It's useless to print machine name and setup arch-specific system
identifiers if of_flat_dt_get_machine_name() return NULL, especially
when ACPI-based boot.
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Unfortunately, it turns out that mismatched CPU features in big.LITTLE
systems are starting to appear in the wild. Whilst we should continue to
taint the kernel with CPU_OUT_OF_SPEC for features that differ in ways
that we can't fix up, dumping a useless backtrace out of the cpufeature
code is pointless and irritating.

This patch removes the backtrace from the taint.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

arm64's mm/mmu.c uses vm_area_add_early, struct vm_area and other
definitions  but relies on implict inclusion of linux/vmalloc.h which
means that changes in other headers could break the build. Thus, add an
explicit include.
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Generic code expects show_regs() to dump the stack, but arm64's
show_regs() does not. This makes it hard to debug softlockups and
other issues that result in show_regs() being called.

This patch updates arm64's show_regs() to dump the stack, as common
code expects.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
[will: folded in bug_handler fix from mrutland]
Signed-off-by: Will Deacon <will.deacon@arm.com>

Generic code expects show_regs() to also dump the stack, but arm64's
show_reg() does not do this. Some arm64 callers of show_regs() *only*
want the registers dumped, without the stack.

To enable generic code to work as expected, we need to make
show_regs() dump the stack. Where we only want the registers dumped,
we must use __show_regs().

This patch updates code to use __show_regs() where only registers are
desired. A subsequent patch will modify show_regs().
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Like arch/arm/, we inherit the READ_IMPLIES_EXEC personality flag across
fork(). This is undesirable for a number of reasons:

  * ELF files that don't require executable stack can end up with it
    anyway

  * We end up performing un-necessary I-cache maintenance when mapping
    what should be non-executable pages

  * Restricting what is executable is generally desirable when defending
    against overflow attacks

This patch clears the personality flag when setting up the personality for
newly spwaned native tasks. Given that semi-recent AArch64 toolchains emit
a non-executable PT_GNU_STACK header, userspace applications can already
not rely on READ_IMPLIES_EXEC so shouldn't be adversely affected by this
change.

Cc: <stable@vger.kernel.org>
Reported-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Dong Bo <dongbo4@huawei.com>
[will: added comment to compat code, rewrote commit message]
Signed-off-by: Will Deacon <will.deacon@arm.com>