Rather than panic() when taking an undefined instruction exception from
EL1, allow a hook to be registered in case we want to emulate the
instruction, like we will for the SSBS PSTATE manipulation instructions.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
As a first step towards invoking syscalls with a pt_regs argument,
convert the raw syscall invocation logic to C. We end up with a bit more
register shuffling, but the unified invocation logic means we can unify
the tracing paths, too.
Previously, assembly had to open-code calls to ni_sys() when the system
call number was out-of-bounds for the relevant syscall table. This case
is now handled by invoke_syscall(), and the assembly no longer need to
handle this case explicitly. This allows the tracing paths to be
simplified and unified, as we no longer need the __ni_sys_trace path and
the __sys_trace_return label.
This only converts the invocation of the syscall. The rest of the
syscall triage and tracing is left in assembly for now, and will be
converted in subsequent patches.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Now that we have sysreg_clear_set(), we can consistently use this
instead of config_sctlr_el1().
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Dave Martin <dave.martin@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Pull siginfo updates from Eric Biederman:
"This set of changes close the known issues with setting si_code to an
invalid value, and with not fully initializing struct siginfo. There
remains work to do on nds32, arc, unicore32, powerpc, arm, arm64, ia64
and x86 to get the code that generates siginfo into a simpler and more
maintainable state. Most of that work involves refactoring the signal
handling code and thus careful code review.
Also not included is the work to shrink the in kernel version of
struct siginfo. That depends on getting the number of places that
directly manipulate struct siginfo under control, as it requires the
introduction of struct kernel_siginfo for the in kernel things.
Overall this set of changes looks like it is making good progress, and
with a little luck I will be wrapping up the siginfo work next
development cycle"
* 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (46 commits)
signal/sh: Stop gcc warning about an impossible case in do_divide_error
signal/mips: Report FPE_FLTUNK for undiagnosed floating point exceptions
signal/um: More carefully relay signals in relay_signal.
signal: Extend siginfo_layout with SIL_FAULT_{MCEERR|BNDERR|PKUERR}
signal: Remove unncessary #ifdef SEGV_PKUERR in 32bit compat code
signal/signalfd: Add support for SIGSYS
signal/signalfd: Remove __put_user from signalfd_copyinfo
signal/xtensa: Use force_sig_fault where appropriate
signal/xtensa: Consistenly use SIGBUS in do_unaligned_user
signal/um: Use force_sig_fault where appropriate
signal/sparc: Use force_sig_fault where appropriate
signal/sparc: Use send_sig_fault where appropriate
signal/sh: Use force_sig_fault where appropriate
signal/s390: Use force_sig_fault where appropriate
signal/riscv: Replace do_trap_siginfo with force_sig_fault
signal/riscv: Use force_sig_fault where appropriate
signal/parisc: Use force_sig_fault where appropriate
signal/parisc: Use force_sig_mceerr where appropriate
signal/openrisc: Use force_sig_fault where appropriate
signal/nios2: Use force_sig_fault where appropriate
...
Call clear_siginfo to ensure every stack allocated siginfo is properly
initialized before being passed to the signal sending functions.
Note: It is not safe to depend on C initializers to initialize struct
siginfo on the stack because C is allowed to skip holes when
initializing a structure.
The initialization of struct siginfo in tracehook_report_syscall_exit
was moved from the helper user_single_step_siginfo into
tracehook_report_syscall_exit itself, to make it clear that the local
variable siginfo gets fully initialized.
In a few cases the scope of struct siginfo has been reduced to make it
clear that siginfo siginfo is not used on other paths in the function
in which it is declared.
Instances of using memset to initialize siginfo have been replaced
with calls clear_siginfo for clarity.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Our arm64_skip_faulting_instruction() helper advances the userspace
singlestep state machine, but this is also called by the kernel BRK
handler, as used for WARN*().
Thus, if we happen to hit a WARN*() while the user singlestep state
machine is in the active-no-pending state, we'll advance to the
active-pending state without having executed a user instruction, and
will take a step exception earlier than expected when we return to
userspace.
Let's fix this by only advancing the state machine when skipping a user
instruction.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Since commit:
a7e6f1ca90 ("arm64: signal: Force SIGKILL for unknown signals in force_signal_inject")
... any signal which is not SIGKILL will be upgraded to a SIGKILL be
force_signal_inject(). This includes signals we do expect, such as
SIGILL triggered by do_undefinstr().
Fix the check to use a logical AND rather than a logical OR, permitting
signals whose layout is SIL_FAULT.
Fixes: a7e6f1ca90 ("arm64: signal: Force SIGKILL for unknown signals in force_signal_inject")
Cc: Will Deacon <will.deacon@arm.com>
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
We issue the enable() call back for all CPU hwcaps capabilities
available on the system, on all the CPUs. So far we have ignored
the argument passed to the call back, which had a prototype to
accept a "void *" for use with on_each_cpu() and later with
stop_machine(). However, with commit 0a0d111d40
("arm64: cpufeature: Pass capability structure to ->enable callback"),
there are some users of the argument who wants the matching capability
struct pointer where there are multiple matching criteria for a single
capability. Clean up the declaration of the call back to make it clear.
1) Renamed to cpu_enable(), to imply taking necessary actions on the
called CPU for the entry.
2) Pass const pointer to the capability, to allow the call back to
check the entry. (e.,g to check if any action is needed on the CPU)
3) We don't care about the result of the call back, turning this to
a void.
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andre Przywara <andre.przywara@arm.com>
Cc: James Morse <james.morse@arm.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Dave Martin <dave.martin@arm.com>
[suzuki: convert more users, rename call back and drop results]
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Using arm64_force_sig_info means that printing messages about unhandled
signals is dealt with for us, so use that in preference to force_sig_info
and remove any homebrew printing code.
Signed-off-by: Will Deacon <will.deacon@arm.com>
show_unhandled_signals_ratelimited is only called in traps.c, so move it
out of its macro in the dreaded system_misc.h and into a static function
in traps.c
Signed-off-by: Will Deacon <will.deacon@arm.com>
arm64_notify_die deals with printing out information regarding unhandled
signals, so there's no need to roll our own code here.
Signed-off-by: Will Deacon <will.deacon@arm.com>
In preparation for consolidating our handling of printing unhandled
signals, introduce a wrapper around force_sig_info which can act as
the canonical place for dealing with show_unhandled_signals.
Initially, we just hook this up to arm64_notify_die.
Signed-off-by: Will Deacon <will.deacon@arm.com>
For signals other than SIGKILL or those with siginfo_layout(signal, code)
== SIL_FAULT then force_signal_inject does not initialise the siginfo_t
properly. Since the signal number is determined solely by the caller,
simply WARN on unknown signals and force to SIGKILL.
Reported-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
force_signal_inject is a little flakey:
* It only knows about SIGILL and SIGSEGV, so can potentially deliver
other signals based on a partially initialised siginfo_t
* It sets si_addr to point at the PC for SIGSEGV
* It always operates on current, so doesn't need the regs argument
This patch fixes these issues by always assigning the si_addr field to
the address parameter of the function and updates the callers (including
those that indirectly call via arm64_notify_segfault) accordingly.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Stop printing a (ratelimited) kernel message for each instance of an
unimplemented syscall being called. Userland making an unimplemented
syscall is not necessarily misbehaviour and to be expected with a
current userland running on an older kernel. Also, the current message
looks scary to users but does not actually indicate a real problem nor
help them narrow down the cause. Just rely on sys_ni_syscall() to return
-ENOSYS.
Cc: <stable@vger.kernel.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Michael Weiser <michael.weiser@gmx.de>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Prior to v8.2, SError is an uncontainable fatal exception. The v8.2 RAS
extensions use SError to notify software about RAS errors, these can be
contained by the Error Syncronization Barrier.
An ACPI system with firmware-first may use SError as its 'SEI'
notification. Future patches may add code to 'claim' this SError as a
notification.
Other systems can distinguish these RAS errors from the SError ESR and
use the AET bits and additional data from RAS-Error registers to handle
the error. Future patches may add this kernel-first handling.
Without support for either of these we will panic(), even if we received
a corrected error. Add code to decode the severity of RAS errors. We can
safely ignore contained errors where the CPU can continue to make
progress. For all other errors we continue to panic().
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Plenty of acronym soup here:
- Initial support for the Scalable Vector Extension (SVE)
- Improved handling for SError interrupts (required to handle RAS events)
- Enable GCC support for 128-bit integer types
- Remove kernel text addresses from backtraces and register dumps
- Use of WFE to implement long delay()s
- ACPI IORT updates from Lorenzo Pieralisi
- Perf PMU driver for the Statistical Profiling Extension (SPE)
- Perf PMU driver for Hisilicon's system PMUs
- Misc cleanups and non-critical fixes
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 updates from Will Deacon:
"The big highlight is support for the Scalable Vector Extension (SVE)
which required extensive ABI work to ensure we don't break existing
applications by blowing away their signal stack with the rather large
new vector context (<= 2 kbit per vector register). There's further
work to be done optimising things like exception return, but the ABI
is solid now.
Much of the line count comes from some new PMU drivers we have, but
they're pretty self-contained and I suspect we'll have more of them in
future.
Plenty of acronym soup here:
- initial support for the Scalable Vector Extension (SVE)
- improved handling for SError interrupts (required to handle RAS
events)
- enable GCC support for 128-bit integer types
- remove kernel text addresses from backtraces and register dumps
- use of WFE to implement long delay()s
- ACPI IORT updates from Lorenzo Pieralisi
- perf PMU driver for the Statistical Profiling Extension (SPE)
- perf PMU driver for Hisilicon's system PMUs
- misc cleanups and non-critical fixes"
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (97 commits)
arm64: Make ARMV8_DEPRECATED depend on SYSCTL
arm64: Implement __lshrti3 library function
arm64: support __int128 on gcc 5+
arm64/sve: Add documentation
arm64/sve: Detect SVE and activate runtime support
arm64/sve: KVM: Hide SVE from CPU features exposed to guests
arm64/sve: KVM: Treat guest SVE use as undefined instruction execution
arm64/sve: KVM: Prevent guests from using SVE
arm64/sve: Add sysctl to set the default vector length for new processes
arm64/sve: Add prctl controls for userspace vector length management
arm64/sve: ptrace and ELF coredump support
arm64/sve: Preserve SVE registers around EFI runtime service calls
arm64/sve: Preserve SVE registers around kernel-mode NEON use
arm64/sve: Probe SVE capabilities and usable vector lengths
arm64: cpufeature: Move sys_caps_initialised declarations
arm64/sve: Backend logic for setting the vector length
arm64/sve: Signal handling support
arm64/sve: Support vector length resetting for new processes
arm64/sve: Core task context handling
arm64/sve: Low-level CPU setup
...
This patch adds the core support for switching and managing the SVE
architectural state of user tasks.
Calls to the existing FPSIMD low-level save/restore functions are
factored out as new functions task_fpsimd_{save,load}(), since SVE
now dynamically may or may not need to be handled at these points
depending on the kernel configuration, hardware features discovered
at boot, and the runtime state of the task. To make these
decisions as fast as possible, const cpucaps are used where
feasible, via the system_supports_sve() helper.
The SVE registers are only tracked for threads that have explicitly
used SVE, indicated by the new thread flag TIF_SVE. Otherwise, the
FPSIMD view of the architectural state is stored in
thread.fpsimd_state as usual.
When in use, the SVE registers are not stored directly in
thread_struct due to their potentially large and variable size.
Because the task_struct slab allocator must be configured very
early during kernel boot, it is also tricky to configure it
correctly to match the maximum vector length provided by the
hardware, since this depends on examining secondary CPUs as well as
the primary. Instead, a pointer sve_state in thread_struct points
to a dynamically allocated buffer containing the SVE register data,
and code is added to allocate and free this buffer at appropriate
times.
TIF_SVE is set when taking an SVE access trap from userspace, if
suitable hardware support has been detected. This enables SVE for
the thread: a subsequent return to userspace will disable the trap
accordingly. If such a trap is taken without sufficient system-
wide hardware support, SIGILL is sent to the thread instead as if
an undefined instruction had been executed: this may happen if
userspace tries to use SVE in a system where not all CPUs support
it for example.
The kernel will clear TIF_SVE and disable SVE for the thread
whenever an explicit syscall is made by userspace. For backwards
compatibility reasons and conformance with the spirit of the base
AArch64 procedure call standard, the subset of the SVE register
state that aliases the FPSIMD registers is still preserved across a
syscall even if this happens. The remainder of the SVE register
state logically becomes zero at syscall entry, though the actual
zeroing work is currently deferred until the thread next tries to
use SVE, causing another trap to the kernel. This implementation
is suboptimal: in the future, the fastpath case may be optimised
to zero the registers in-place and leave SVE enabled for the task,
where beneficial.
TIF_SVE is also cleared in the following slowpath cases, which are
taken as reasonable hints that the task may no longer use SVE:
* exec
* fork and clone
Code is added to sync data between thread.fpsimd_state and
thread.sve_state whenever enabling/disabling SVE, in a manner
consistent with the SVE architectural programmer's model.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Alex Bennée <alex.bennee@linaro.org>
[will: added #include to fix allnoconfig build]
[will: use enable_daif in do_sve_acc]
Signed-off-by: Will Deacon <will.deacon@arm.com>
The SVE architecture adds some system registers, ID register fields
and a dedicated ESR exception class.
This patch adds the appropriate definitions that will be needed by
the kernel.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
It's possible for a user to deliberately trigger __dump_instr with a
chosen kernel address.
Let's avoid problems resulting from this by using get_user() rather than
__get_user(), ensuring that we don't erroneously access kernel memory.
Where we use __dump_instr() on kernel text, we already switch to
KERNEL_DS, so this shouldn't adversely affect those cases.
Fixes: 60ffc30d56 ("arm64: Exception handling")
Cc: stable@vger.kernel.org
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Today SError is taken using the inv_entry macro that ends up in
bad_mode.
SError can be used by the RAS Extensions to notify either the OS or
firmware of CPU problems, some of which may have been corrected.
To allow this handling to be added, add a do_serror() C function
that just panic()s. Add the entry.S boiler plate to save/restore the
CPU registers and unmask debug exceptions. Future patches may change
do_serror() to return if the SError Interrupt was notification of a
corrected error.
Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: Wang Xiongfeng <wangxiongfengi2@huawei.com>
[Split out of a bigger patch, added compat path, renamed, enabled debug
exceptions]
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
There are a few places where we want to mask all exceptions. Today we
do this in a piecemeal fashion, typically we expect the caller to
have masked irqs and the arch code masks debug exceptions, ignoring
serror which is probably masked.
Make it clear that 'mask all exceptions' is the intention by adding
helpers to do exactly that.
This will let us unmask SError without having to add 'oh and SError'
to these paths.
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Julien Thierry <julien.thierry@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Printing raw pointer values in backtraces has potential security
implications and are of questionable value anyway.
This patch follows x86's lead and removes the "Exception stack:" dump
from kernel backtraces, as well as converting PC/LR values to symbols
such as "sysrq_handle_crash+0x20/0x30".
Tested-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Software Step exception is missing after stepping a trapped instruction.
Ensure SPSR.SS gets set to 0 after emulating/skipping a trapped instruction
before doing ERET.
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
[will: replaced AARCH32_INSN_SIZE with 4]
Signed-off-by: Will Deacon <will.deacon@arm.com>
Both unwind_frame() and dump_backtrace() try to check whether a stack
address is sane to access, with very similar logic. Both will need
updating in order to handle overflow stacks.
Factor out this logic into a helper, so that we can avoid further
duplication when we add overflow stacks.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Our __die() implementation tries to dump the stack memory, in addition
to a backtrace, which is problematic.
For contemporary 16K stacks, this can be a lot of data, which can take a
long time to dump, and can push other useful context out of the kernel's
printk ringbuffer (and/or a user's scrollback buffer on an attached
console).
Additionally, the code implicitly assumes that the SP is on the task's
stack, and tries to dump everything between the SP and the highest task
stack address. When the SP points at an IRQ stack (or is corrupted),
this makes the kernel attempt to dump vast amounts of VA space. With
vmap'd stacks, this may result in erroneous accesses to peripherals.
This patch removes the memory dump, leaving us to rely on the backtrace,
and other means of dumping stack memory such as kdump.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
The unwind code sets the sp member of struct stackframe to
'frame pointer + 0x10' unconditionally, without regard for whether
doing so produces a legal value. So let's simply remove it now that
we have stopped using it anyway.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
As it turns out, the unwind code is slightly broken, and probably has
been for a while. The problem is in the dumping of the exception stack,
which is intended to dump the contents of the pt_regs struct at each
level in the call stack where an exception was taken and routed to a
routine marked as __exception (which means its stack frame is right
below the pt_regs struct on the stack).
'Right below the pt_regs struct' is ill defined, though: the unwind
code assigns 'frame pointer + 0x10' to the .sp member of the stackframe
struct at each level, and dump_backtrace() happily dereferences that as
the pt_regs pointer when encountering an __exception routine. However,
the actual size of the stack frame created by this routine (which could
be one of many __exception routines we have in the kernel) is not known,
and so frame.sp is pretty useless to figure out where struct pt_regs
really is.
So it seems the only way to ensure that we can find our struct pt_regs
when walking the stack frames is to put it at a known fixed offset of
the stack frame pointer that is passed to such __exception routines.
The simplest way to do that is to put it inside pt_regs itself, which is
the main change implemented by this patch. As a bonus, doing this allows
us to get rid of a fair amount of cruft related to walking from one stack
to the other, which is especially nice since we intend to introduce yet
another stack for overflow handling once we add support for vmapped
stacks. It also fixes an inconsistency where we only add a stack frame
pointing to ELR_EL1 if we are executing from the IRQ stack but not when
we are executing from the task stack.
To consistly identify exceptions regs even in the presence of exceptions
taken from entry code, we must check whether the next frame was created
by entry text, rather than whether the current frame was crated by
exception text.
To avoid backtracing using PCs that fall in the idmap, or are controlled
by userspace, we must explcitly zero the FP and LR in startup paths, and
must ensure that the frame embedded in pt_regs is zeroed upon entry from
EL0. To avoid these NULL entries showin in the backtrace, unwind_frame()
is updated to avoid them.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
[Mark: compare current frame against .entry.text, avoid bogus PCs]
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cache clean to PoP is subject to the same access controls as to PoC, so
if we are trapping userspace cache maintenance with SCTLR_EL1.UCI, we
need to be prepared to handle it. To avoid getting into complicated
fights with binutils about ARMv8.2 options, we'll just cheat and use the
raw SYS instruction rather than the 'proper' DC alias.
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Our IRQ_STACK_PTR() and on_irq_stack() helpers both take a cpu argument,
used to generate a percpu address. In all cases, they are passed
{raw_,}smp_processor_id(), so this parameter is redundant.
Since {raw_,}smp_processor_id() use a percpu variable internally, this
approach means we generate a percpu offset to find the current cpu, then
use this to index an array of percpu offsets, which we then use to find
the current CPU's IRQ stack pointer. Thus, most of the work is
redundant.
Instead, we can consistently use raw_cpu_ptr() to generate the CPU's
irq_stack pointer by simply adding the percpu offset to the irq_stack
address, which is simpler in both respects.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
The upper 32 bits of the syscallno field in thread_struct are
handled inconsistently, being sometimes zero extended and sometimes
sign-extended. In fact, only the lower 32 bits seem to have any
real significance for the behaviour of the code: it's been OK to
handle the upper bits inconsistently because they don't matter.
Currently, the only place I can find where those bits are
significant is in calling trace_sys_enter(), which may be
unintentional: for example, if a compat tracer attempts to cancel a
syscall by passing -1 to (COMPAT_)PTRACE_SET_SYSCALL at the
syscall-enter-stop, it will be traced as syscall 4294967295
rather than -1 as might be expected (and as occurs for a native
tracer doing the same thing). Elsewhere, reads of syscallno cast
it to an int or truncate it.
There's also a conspicuous amount of code and casting to bodge
around the fact that although semantically an int, syscallno is
stored as a u64.
Let's not pretend any more.
In order to preserve the stp x instruction that stores the syscall
number in entry.S, this patch special-cases the layout of struct
pt_regs for big endian so that the newly 32-bit syscallno field
maps onto the low bits of the stored value. This is not beautiful,
but benchmarking of the getpid syscall on Juno suggests indicates a
minor slowdown if the stp is split into an stp x and stp w.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
In an ideal world, CNTFRQ_EL0 always contains the timer frequency
for the kernel to use. Sadly, we get quite a few broken systems
where the firmware authors cannot be bothered to program that
register on all CPUs, and rely on DT to provide that frequency.
So when trapping CNTFRQ_EL0, make sure to return the actual rate
(as known by the kernel), and not CNTFRQ_EL0.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
In current die(), the irq is disabled for __die() handle, not
including the possible panic() handling. Since the log in __die()
can take several hundreds ms, new irq might come and interrupt
current die().
If the process calling die() holds some critical resource, and some
other process scheduled later also needs it, then it would deadlock.
The first panic will not be executed.
So here disable irq for the whole flow of die().
Signed-off-by: Qiao Zhou <qiaozhou@asrmicro.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Here we're reading thumb or ARM instructions, which are always
stored in memory in little-endian order. These values are thus
correctly converted to native order but the intermediate value
should be annotated as for little-endian values.
Fix this by declaring the intermediate var as __le32 or __le16.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
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>
When we emulate userspace cache maintenance in the kernel, we can
currently send the task a SIGSEGV even though the maintenance was done
on a valid address. This happens if the address has a non-zero address
tag, and happens to not be mapped in.
When we get the address from a user register, we don't currently remove
the address tag before performing cache maintenance on it. If the
maintenance faults, we end up in either __do_page_fault, where find_vma
can't find the VMA if the address has a tag, or in do_translation_fault,
where the tagged address will appear to be above TASK_SIZE. In both
cases, the address is not mapped in, and the task is sent a SIGSEGV.
This patch removes the tag from the address before using it. With this
patch, the fault is handled correctly, the address gets mapped in, and
the cache maintenance succeeds.
As a second bug, if cache maintenance (correctly) fails on an invalid
tagged address, the address gets passed into arm64_notify_segfault,
where find_vma fails to find the VMA due to the tag, and the wrong
si_code may be sent as part of the siginfo_t of the segfault. With this
patch, the correct si_code is sent.
Fixes: 7dd01aef05 ("arm64: trap userspace "dc cvau" cache operation on errata-affected core")
Cc: <stable@vger.kernel.org> # 4.8.x-
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
We now trap accesses to CNTVCT_EL0 when the counter is broken
enough to require the kernel to mediate the access. But it
turns out that some existing userspace (such as OpenMPI) do
probe for the counter frequency, leading to an UNDEF exception
as CNTVCT_EL0 and CNTFRQ_EL0 share the same control bit.
The fix is to handle the exception the same way we do for CNTVCT_EL0.
Fixes: a86bd139f2 ("arm64: arch_timer: Enable CNTVCT_EL0 trap if workaround is enabled")
Reported-by: Hanjun Guo <guohanjun@huawei.com>
Tested-by: Hanjun Guo <guohanjun@huawei.com>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Since people seem to make a point in breaking the userspace visible
counter, we have no choice but to trap the access. Add the required
handler.
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Update code that relied on sched.h including various MM types for them.
This will allow us to remove the <linux/mm_types.h> include from <linux/sched.h>.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We are going to split <linux/sched/task_stack.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.
Create a trivial placeholder <linux/sched/task_stack.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.
Include the new header in the files that are going to need it.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We are going to split <linux/sched/debug.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.
Create a trivial placeholder <linux/sched/debug.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.
Include the new header in the files that are going to need it.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We are going to split <linux/sched/signal.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.
Create a trivial placeholder <linux/sched/signal.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.
Include the new header in the files that are going to need it.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
- Errata workarounds for Qualcomm's Falkor CPU
- Qualcomm L2 Cache PMU driver
- Qualcomm SMCCC firmware quirk
- Support for DEBUG_VIRTUAL
- CPU feature detection for userspace via MRS emulation
- Preliminary work for the Statistical Profiling Extension
- Misc cleanups and non-critical fixes
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 updates from Will Deacon:
- Errata workarounds for Qualcomm's Falkor CPU
- Qualcomm L2 Cache PMU driver
- Qualcomm SMCCC firmware quirk
- Support for DEBUG_VIRTUAL
- CPU feature detection for userspace via MRS emulation
- Preliminary work for the Statistical Profiling Extension
- Misc cleanups and non-critical fixes
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (74 commits)
arm64/kprobes: consistently handle MRS/MSR with XZR
arm64: cpufeature: correctly handle MRS to XZR
arm64: traps: correctly handle MRS/MSR with XZR
arm64: ptrace: add XZR-safe regs accessors
arm64: include asm/assembler.h in entry-ftrace.S
arm64: fix warning about swapper_pg_dir overflow
arm64: Work around Falkor erratum 1003
arm64: head.S: Enable EL1 (host) access to SPE when entered at EL2
arm64: arch_timer: document Hisilicon erratum 161010101
arm64: use is_vmalloc_addr
arm64: use linux/sizes.h for constants
arm64: uaccess: consistently check object sizes
perf: add qcom l2 cache perf events driver
arm64: remove wrong CONFIG_PROC_SYSCTL ifdef
ARM: smccc: Update HVC comment to describe new quirk parameter
arm64: do not trace atomic operations
ACPI/IORT: Fix the error return code in iort_add_smmu_platform_device()
ACPI/IORT: Fix iort_node_get_id() mapping entries indexing
arm64: mm: enable CONFIG_HOLES_IN_ZONE for NUMA
perf: xgene: Include module.h
...
Currently we hand-roll XZR-safe register handling in
user_cache_maint_handler(), though we forget to do the same in
ctr_read_handler(), and may erroneously write back to the user SP rather
than XZR.
Use the new helpers to handle these cases correctly and consistently.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Fixes: 116c81f427 ("arm64: Work around systems with mismatched cache line sizes")
Cc: Andre Przywara <andre.przywara@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marc Zyngier <marc.zyngier@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>
If an EL0 instruction in the SYS class triggers an exception, do_sysintr
looks for a sys64_hook matching the instruction, and if none is found,
injects a SIGILL. This mirrors what we do for undefined instruction
encodings in do_undefinstr, where we look for an undef_hook matching the
instruction, and if none is found, inject a SIGILL.
Over time, new SYS instruction encodings may be allocated. Prior to
allocation, exceptions resulting from these would be handled by
do_undefinstr, whereas after allocation these may be handled by
do_sysintr.
To ensure that we have consistent behaviour if and when this happens, it
would be beneficial to have do_sysinstr fall back to do_undefinstr.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Suzuki Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Generally, taking an unexpected exception should be a fatal event, and
bad_mode is intended to cater for this. However, it should be possible
to contain unexpected synchronous exceptions from EL0 without bringing
the kernel down, by sending a SIGILL to the task.
We tried to apply this approach in commit 9955ac47f4 ("arm64:
don't kill the kernel on a bad esr from el0"), by sending a signal for
any bad_mode call resulting from an EL0 exception.
However, this also applies to other unexpected exceptions, such as
SError and FIQ. The entry paths for these exceptions branch to bad_mode
without configuring the link register, and have no kernel_exit. Thus, if
we take one of these exceptions from EL0, bad_mode will eventually
return to the original user link register value.
This patch fixes this by introducing a new bad_el0_sync handler to cater
for the recoverable case, and restoring bad_mode to its original state,
whereby it calls panic() and never returns. The recoverable case
branches to bad_el0_sync with a bl, and returns to userspace via the
usual ret_to_user mechanism.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Fixes: 9955ac47f4 ("arm64: don't kill the kernel on a bad esr from el0")
Reported-by: Mark Salter <msalter@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: stable@vger.kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Track the user visible fields of a CPU feature register. This will be
used for exposing the value to the userspace. All the user visible
fields of a feature register will be passed on as it is, while the
others would be filled with their respective safe value.
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
When the TTBR0 PAN feature is enabled, the kernel entry points need to
disable access to TTBR0_EL1. The PAN status of the interrupted context
is stored as part of the saved pstate, reusing the PSR_PAN_BIT (22).
Restoring access to TTBR0_EL1 is done on exception return if returning
to user or returning to a context where PAN was disabled.
Context switching via switch_mm() must defer the update of TTBR0_EL1
until a return to user or an explicit uaccess_enable() call.
Special care needs to be taken for two cases where TTBR0_EL1 is set
outside the normal kernel context switch operation: EFI run-time
services (via efi_set_pgd) and CPU suspend (via cpu_(un)install_idmap).
Code has been added to avoid deferred TTBR0_EL1 switching as in
switch_mm() and restore the reserved TTBR0_EL1 when uninstalling the
special TTBR0_EL1.
User cache maintenance (user_cache_maint_handler and
__flush_cache_user_range) needs the TTBR0_EL1 re-instated since the
operations are performed by user virtual address.
This patch also removes a stale comment on the switch_mm() function.
Cc: Will Deacon <will.deacon@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
When CONFIG_THREAD_INFO_IN_TASK is selected, task stacks may be freed
before a task is destroyed. To account for this, the stacks are
refcounted, and when manipulating the stack of another task, it is
necessary to get/put the stack to ensure it isn't freed and/or re-used
while we do so.
This patch reworks the arm64 stack walking code to account for this.
When CONFIG_THREAD_INFO_IN_TASK is not selected these perform no
refcounting, and this should only be a structural change that does not
affect behaviour.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
In arm64's die and __die routines we pass around a thread_info, and
subsequently use this to determine the relevant task_struct, and the end
of the thread's stack. Subsequent patches will decouple thread_info from
the stack, and this approach will no longer work.
To figure out the end of the stack, we can use the new generic
end_of_stack() helper. As we only call __die() from die(), and die()
always deals with the current task, we can remove the parameter and have
both acquire current directly, which also makes it clear that __die
can't be called for arbitrary tasks.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
We define current_stack_pointer in <asm/thread_info.h>, though other
files and header relying upon it do not have this necessary include, and
are thus fragile to changes in the header soup.
Subsequent patches will affect the header soup such that directly
including <asm/thread_info.h> may result in a circular header include in
some of these cases, so we can't simply include <asm/thread_info.h>.
Instead, factor current_thread_info into its own header, and have all
existing users include this explicitly.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The enable() call for a cpufeature/errata is called using on_each_cpu().
This issues a cross-call IPI to get the work done. Implicitly, this
stashes the running PSTATE in SPSR when the CPU receives the IPI, and
restores it when we return. This means an enable() call can never modify
PSTATE.
To allow PAN to do this, change the on_each_cpu() call to use
stop_machine(). This schedules the work on each CPU which allows
us to modify PSTATE.
This involves changing the protype of all the enable() functions.
enable_cpu_capabilities() is called during boot and enables the feature
on all online CPUs. This path now uses stop_machine(). CPU features for
hotplug'd CPUs are enabled by verify_local_cpu_features() which only
acts on the local CPU, and can already modify the running PSTATE as it
is called from secondary_start_kernel().
Reported-by: Tony Thompson <anthony.thompson@arm.com>
Reported-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Commit 7dd01aef05 ("arm64: trap userspace "dc cvau" cache operation on
errata-affected core") adds code to execute cache maintenance instructions
in the kernel on behalf of userland on CPUs with certain ARM CPU errata.
It turns out that the address hasn't been checked to be a valid user
space address, allowing userland to clean cache lines in kernel space.
Fix this by introducing an address check before executing the
instructions on behalf of userland.
Since the address doesn't come via a syscall parameter, we can't just
reject tagged pointers and instead have to remove the tag when checking
against the user address limit.
Cc: <stable@vger.kernel.org>
Fixes: 7dd01aef05 ("arm64: trap userspace "dc cvau" cache operation on errata-affected core")
Reported-by: Kristina Martsenko <kristina.martsenko@arm.com>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
[will: rework commit message + replace access_ok with max_user_addr()]
Signed-off-by: Will Deacon <will.deacon@arm.com>
In some places, dump_backtrace() is called with a NULL tsk parameter,
e.g. in bug_handler() in arch/arm64, or indirectly via show_stack() in
core code. The expectation is that this is treated as if current were
passed instead of NULL. Similar is true of unwind_frame().
Commit a80a0eb70c ("arm64: make irq_stack_ptr more robust") didn't
take this into account. In dump_backtrace() it compares tsk against
current *before* we check if tsk is NULL, and in unwind_frame() we never
set tsk if it is NULL.
Due to this, we won't initialise irq_stack_ptr in either function. In
dump_backtrace() this results in calling dump_mem() for memory
immediately above the IRQ stack range, rather than for the relevant
range on the task stack. In unwind_frame we'll reject unwinding frames
on the IRQ stack.
In either case this results in incomplete or misleading backtrace
information, but is not otherwise problematic. The initial percpu areas
(including the IRQ stacks) are allocated in the linear map, and dump_mem
uses __get_user(), so we shouldn't access anything with side-effects,
and will handle holes safely.
This patch fixes the issue by having both functions handle the NULL tsk
case before doing anything else with tsk.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Fixes: a80a0eb70c ("arm64: make irq_stack_ptr more robust")
Acked-by: James Morse <james.morse@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yang Shi <yang.shi@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Systems with differing CPU i-cache/d-cache line sizes can cause
problems with the cache management by software when the execution
is migrated from one to another. Usually, the application reads
the cache size on a CPU and then uses that length to perform cache
operations. However, if it gets migrated to another CPU with a smaller
cache line size, things could go completely wrong. To prevent such
cases, always use the smallest cache line size among the CPUs. The
kernel CPU feature infrastructure already keeps track of the safe
value for all CPUID registers including CTR. This patch works around
the problem by :
For kernel, dynamically patch the kernel to read the cache size
from the system wide copy of CTR_EL0.
For applications, trap read accesses to CTR_EL0 (by clearing the SCTLR.UCT)
and emulate the mrs instruction to return the system wide safe value
of CTR_EL0.
For faster access (i.e, avoiding to lookup the system wide value of CTR_EL0
via read_system_reg), we keep track of the pointer to table entry for
CTR_EL0 in the CPU feature infrastructure.
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andre Przywara <andre.przywara@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Right now we trap some of the user space data cache operations
based on a few Errata (ARM 819472, 826319, 827319 and 824069).
We need to trap userspace access to CTR_EL0, if we detect mismatched
cache line size. Since both these traps share the EC, refactor
the handler a little bit to make it a bit more reader friendly.
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
The ARM errata 819472, 826319, 827319 and 824069 for affected
Cortex-A53 cores demand to promote "dc cvau" instructions to
"dc civac". Since we allow userspace to also emit those instructions,
we should make sure that "dc cvau" gets promoted there too.
So lets grasp the nettle here and actually trap every userland cache
maintenance instruction once we detect at least one affected core in
the system.
We then emulate the instruction by executing it on behalf of userland,
promoting "dc cvau" to "dc civac" on the way and injecting access
fault back into userspace.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
[catalin.marinas@arm.com: s/set_segfault/arm64_notify_segfault/]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The code for injecting a signal into userland if a trapped instruction
fails emulation due to a _userland_ error (like an illegal address)
will be used more often with the next patch.
Factor out the core functionality into a separate function and use
that both for the existing trap handler and for the deprecated
instructions emulation.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
[catalin.marinas@arm.com: s/set_segfault/arm64_notify_segfault/]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Several places open-code extraction of the EC field from an ESR_ELx
value, in subtly different ways. This is unfortunate duplication and
variation, and the precise logic used to extract the field is a
distraction.
This patch adds a new macro, ESR_ELx_EC(), to extract the EC field from
an ESR_ELx value in a consistent fashion.
Existing open-coded extractions in core arm64 code are moved over to the
new helper. KVM code is left as-is for the moment.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Huang Shijie <shijie.huang@arm.com>
Cc: Dave P Martin <dave.martin@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Currently dump_mem attempts to dump memory in 64-bit chunks when
reporting a failure in 64-bit code, or 32-bit chunks when reporting a
failure in 32-bit code. We added code to handle these two cases
separately in commit e147ae6d7f ("arm64: modify the dump mem for
64 bit addresses").
However, in all cases dump_mem is called, the failing context is a
kernel rather than user context. Additionally dump_mem is assumed to
only be used for kernel contexts, as internally it switches to
KERNEL_DS, and its callers pass kernel stack bounds.
This patch removes the redundant 32-bit chunk logic and associated
compat parameter, largely reverting the aforementioned commit. For the
call in __die(), the check of in_interrupt() is removed also, as __die()
is only called in response to faults from the kernel's exception level,
and thus the !user_mode(regs) check is sufficient. Were this not the
case, the used of task_stack_page(tsk) to generate the stack bounds
would be erroneous.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
If the kernel is set to show unhandled signals, and a user task does not
handle a SIGILL as a result of an instruction abort, we will attempt to
log the offending instruction with dump_instr before killing the task.
We use dump_instr to log the encoding of the offending userspace
instruction. However, dump_instr is also used to dump instructions from
kernel space, and internally always switches to KERNEL_DS before dumping
the instruction with get_user. When both PAN and UAO are in use, reading
a user instruction via get_user while in KERNEL_DS will result in a
permission fault, which leads to an Oops.
As we have regs corresponding to the context of the original instruction
abort, we can inspect this and only flip to KERNEL_DS if the original
abort was taken from the kernel, avoiding this issue. At the same time,
remove the redundant (and incorrect) comments regarding the order
dump_mem and dump_instr are called in.
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: <stable@vger.kernel.org> #4.6+
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reported-by: Vladimir Murzin <vladimir.murzin@arm.com>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com>
Fixes: 57f4959bad ("arm64: kernel: Add support for User Access Override")
Signed-off-by: Will Deacon <will.deacon@arm.com>
If we take an exception we don't expect (e.g. SError), we report this in
the bad_mode handler with pr_crit. Depending on the configured log
level, we may or may not log additional information in functions called
subsequently. Notably, the messages in dump_stack (including the CPU
number) are printed with KERN_DEFAULT and may not appear.
Some exceptions have an IMPLEMENTATION DEFINED ESR_ELx.ISS encoding, and
knowing the CPU number is crucial to correctly decode them. To ensure
that this is always possible, we should log the CPU number along with
the ESR_ELx value, so we are not reliant on subsequent logs or
additional printk configuration options.
This patch logs the CPU number in bad_mode such that it is possible for
a developer to decode these exceptions, provided access to sufficient
documentation.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reported-by: Al Grant <Al.Grant@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Martin <dave.martin@arm.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Switching between stacks is only valid if we are tracing ourselves while on the
irq_stack, so it is only valid when in current and non-preemptible context,
otherwise is is just zeroed off.
Fixes: 132cd887b5 ("arm64: Modify stack trace and dump for use with irq_stack")
Acked-by: James Morse <james.morse@arm.com>
Tested-by: James Morse <james.morse@arm.com>
Signed-off-by: Yang Shi <yang.shi@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Commit ac7b406c1a ("arm64: Use pr_* instead of printk") was a fairly
mindless s/printk/pr_*/ change driven by a complaint from checkpatch.
As is usual with such changes, this has led to some odd behaviour on
arm64:
* syslog now picks up the "pr_emerg" line from dump_backtrace, but not
the actual trace, which leads to a bunch of "kernel:Call trace:"
lines in the log
* __{pte,pmd,pgd}_error print at KERN_CRIT, as opposed to KERN_ERR
which is used by other architectures.
This patch restores the original printk behaviour for dump_backtrace
and downgrade the pgtable error macros to KERN_ERR.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Function graph tracer modifies a return address (LR) in a stack frame
to hook a function return. This will result in many useless entries
(return_to_handler) showing up in
a) a stack tracer's output
b) perf call graph (with perf record -g)
c) dump_backtrace (at panic et al.)
For example, in case of a),
$ echo function_graph > /sys/kernel/debug/tracing/current_tracer
$ echo 1 > /proc/sys/kernel/stack_trace_enabled
$ cat /sys/kernel/debug/tracing/stack_trace
Depth Size Location (54 entries)
----- ---- --------
0) 4504 16 gic_raise_softirq+0x28/0x150
1) 4488 80 smp_cross_call+0x38/0xb8
2) 4408 48 return_to_handler+0x0/0x40
3) 4360 32 return_to_handler+0x0/0x40
...
In case of b),
$ echo function_graph > /sys/kernel/debug/tracing/current_tracer
$ perf record -e mem:XXX:x -ag -- sleep 10
$ perf report
...
| | |--0.22%-- 0x550f8
| | | 0x10888
| | | el0_svc_naked
| | | sys_openat
| | | return_to_handler
| | | return_to_handler
...
In case of c),
$ echo function_graph > /sys/kernel/debug/tracing/current_tracer
$ echo c > /proc/sysrq-trigger
...
Call trace:
[<ffffffc00044d3ac>] sysrq_handle_crash+0x24/0x30
[<ffffffc000092250>] return_to_handler+0x0/0x40
[<ffffffc000092250>] return_to_handler+0x0/0x40
...
This patch replaces such entries with real addresses preserved in
current->ret_stack[] at unwind_frame(). This way, we can cover all
the cases.
Reviewed-by: Jungseok Lee <jungseoklee85@gmail.com>
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
[will: fixed minor context changes conflicting with irq stack bits]
Signed-off-by: Will Deacon <will.deacon@arm.com>
Function graph tracer modifies a return address (LR) in a stack frame
to hook a function's return. This will result in many useless entries
(return_to_handler) showing up in a call stack list.
We will fix this problem in a later patch ("arm64: ftrace: fix a stack
tracer's output under function graph tracer"). But since real return
addresses are saved in ret_stack[] array in struct task_struct,
unwind functions need to be notified of, in addition to a stack pointer
address, which task is being traced in order to find out real return
addresses.
This patch extends unwind functions' interfaces by adding an extra
argument of a pointer to task_struct.
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This patch allows unwind_frame() to traverse from interrupt stack to task
stack correctly. It requires data from a dummy stack frame, created
during irq_stack_entry(), added by a later patch.
A similar approach is taken to modify dump_backtrace(), which expects to
find struct pt_regs underneath any call to functions marked __exception.
When on an irq_stack, the struct pt_regs is stored on the old task stack,
the location of which is stored in the dummy stack frame.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
[james.morse: merged two patches, reworked for per_cpu irq_stacks, and
no alignment guarantees, added irq_stack definitions]
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Unlike perf callchain relying on walk_stackframe(), dump_backtrace()
has its own backtrace logic. A major difference between them is the
moment a symbol is recorded. Perf writes down a symbol *before*
calling unwind_frame(), but dump_backtrace() prints it out *after*
unwind_frame(). As a result, the last valid symbol cannot be hooked
in case of dump_backtrace(). This patch addresses the issue as
synchronising dump_backtrace() with perf callchain.
A simple test and its results are as follows:
- crash trigger
$ sudo echo c > /proc/sysrq-trigger
- current status
Call trace:
[<fffffe00003dc738>] sysrq_handle_crash+0x24/0x30
[<fffffe00003dd2ac>] __handle_sysrq+0x128/0x19c
[<fffffe00003dd730>] write_sysrq_trigger+0x60/0x74
[<fffffe0000249fc4>] proc_reg_write+0x84/0xc0
[<fffffe00001f2638>] __vfs_write+0x44/0x104
[<fffffe00001f2e60>] vfs_write+0x98/0x1a8
[<fffffe00001f3730>] SyS_write+0x50/0xb0
- with this change
Call trace:
[<fffffe00003dc738>] sysrq_handle_crash+0x24/0x30
[<fffffe00003dd2ac>] __handle_sysrq+0x128/0x19c
[<fffffe00003dd730>] write_sysrq_trigger+0x60/0x74
[<fffffe0000249fc4>] proc_reg_write+0x84/0xc0
[<fffffe00001f2638>] __vfs_write+0x44/0x104
[<fffffe00001f2e60>] vfs_write+0x98/0x1a8
[<fffffe00001f3730>] SyS_write+0x50/0xb0
[<fffffe00000939ec>] el0_svc_naked+0x20/0x28
Note that this patch does not cover a case where MMU is disabled. The
last stack frame of swapper, for example, has PC in a form of physical
address. Unfortunately, a simple conversion using phys_to_virt() cannot
cover all scenarios since PC is retrieved from LR - 4, not LR. It is
a big tradeoff to change both head.S and unwind_frame() for only a few
of symbols in *.S. Thus, this hunk does not take care of the case.
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: James Morse <james.morse@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Jungseok Lee <jungseoklee85@gmail.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The generic slowpath WARN implementation prints a backtrace, but
the report_bug() based implementation does not, opting to print the
registers instead which is generally not as useful.
Ideally, report_bug() should be fixed to make the behaviour more
consistent, but in the meantime this patch generates a backtrace
directly from the arm64 backend instead so that this functionality
is not lost with the migration to report_bug().
As a side-effect, the backtrace will be outside the oops end
marker, but that's hard to avoid without modifying generic code.
This patch can go away if report_bug() grows the ability in the
future to generate a backtrace directly or call an arch hook at the
appropriate time.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Currently, the minimal default BUG() implementation from asm-
generic is used for arm64.
This patch uses the BRK software breakpoint instruction to generate
a trap instead, similarly to most other arches, with the generic
BUG code generating the dmesg boilerplate.
This allows bug metadata to be moved to a separate table and
reduces the amount of inline code at BUG and WARN sites. This also
avoids clobbering any registers before they can be dumped.
To mitigate the size of the bug table further, this patch makes
use of the existing infrastructure for encoding addresses within
the bug table as 32-bit offsets instead of absolute pointers.
(Note that this limits the kernel size to 2GB.)
Traps are registered at arch_initcall time for aarch64, but BUG
has minimal real dependencies and it is desirable to be able to
generate bug splats as early as possible. This patch redirects
all debug exceptions caused by BRK directly to bug_handler() until
the full debug exception support has been initialised.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Nobody seems to be producing !SMP systems anymore, so this is just
becoming a source of kernel bugs, particularly if people want to use
coherent DMA with non-shared pages.
This patch forces CONFIG_SMP=y for arm64, removing a modest amount of
code in the process.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Commit 86dca36e6b introduced ratelimited usage for
'unhandled_signal' messages.
The commit checks the ratelimit irrespective of whether
the signal is handled or not, which is wrong and leads
to false reports like the below in dmesg :
__do_user_fault: 127 callbacks suppressed
Do the ratelimit check only if the signal is unhandled.
Fixes: 86dca36e6b ("arm64: use private ratelimit state along with show_unhandled_signals")
Cc: Vladimir Murzin <Vladimir.Murzin@arm.com>
Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
printk_ratelimit() shares the ratelimiting state with other callers what
may lead to scenarios where at the time we want to print out debug
information we already limited, so nothing appears in the dmesg - this
makes exception-trace quite poor helper in debugging.
Additionally, we have imbalance with some messages limited with global
ratelimit state and other messages limited with their private state
defined via pr_*_ratelimited().
To address this inconsistency show_unhandled_signals_ratelimited()
macro is introduced and caller sites are converted to use it.
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
To aid the developer when something triggers an unexpected exception,
decode the ESR_ELx.EC field when logging an ESR_ELx value. This doesn't
tell the developer the specifics of the exception encoded in the
remaining IL and ISS bits, but it can be helpful to distinguish between
exception classes (e.g. SError and a data abort) without having to
manually decode the field, which can be tiresome.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Peter Maydell <peter.maydell@linaro.org>
Cc: Will Deacon <will.deacon@arm.com>
Add support to register hooks for undefined instructions. The handlers
will be called when the undefined instruction and the processor state
(as contained in pstate) match criteria used at registration.
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Use the global current_stack_pointer to get the value of the stack pointer.
This change supports being able to compile the kernel with both gcc and clang.
Signed-off-by: Behan Webster <behanw@converseincode.com>
Signed-off-by: Mark Charlebois <charlebm@gmail.com>
Reviewed-by: Olof Johansson <olof@lixom.net>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This patch implements 4 levels of translation tables since 3 levels
of page tables with 4KB pages cannot support 40-bit physical address
space described in [1] due to the following issue.
It is a restriction that kernel logical memory map with 4KB + 3 levels
(0xffffffc000000000-0xffffffffffffffff) cannot cover RAM region from
544GB to 1024GB in [1]. Specifically, ARM64 kernel fails to create
mapping for this region in map_mem function since __phys_to_virt for
this region reaches to address overflow.
If SoC design follows the document, [1], over 32GB RAM would be placed
from 544GB. Even 64GB system is supposed to use the region from 544GB
to 576GB for only 32GB RAM. Naturally, it would reach to enable 4 levels
of page tables to avoid hacking __virt_to_phys and __phys_to_virt.
However, it is recommended 4 levels of page table should be only enabled
if memory map is too sparse or there is about 512GB RAM.
References
----------
[1]: Principles of ARM Memory Maps, White Paper, Issue C
Signed-off-by: Jungseok Lee <jays.lee@samsung.com>
Reviewed-by: Sungjinn Chung <sungjinn.chung@samsung.com>
Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Reviewed-by: Steve Capper <steve.capper@linaro.org>
[catalin.marinas@arm.com: MEMBLOCK_INITIAL_LIMIT removed, same as PUD_SIZE]
[catalin.marinas@arm.com: early_ioremap_init() updated for 4 levels]
[catalin.marinas@arm.com: 48-bit VA depends on BROKEN until KVM is fixed]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Jungseok Lee <jungseoklee85@gmail.com>
This patch fixed the following checkpatch complaint as using pr_*
instead of printk.
WARNING: printk() should include KERN_ facility level
Signed-off-by: Jungseok Lee <jays.lee@samsung.com>
Reviewed-by: Sungjinn Chung <sungjinn.chung@samsung.com>
Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
For AArch32, bit 11 (WnR) of the FSR/ESR register is set when the fault
was caused by a write access and applications like Qemu rely on such
information being provided in sigcontext. This patch introduces the
ESR_EL1 tracking for the arm64 kernel faults and sets bit 11 accordingly
in compat sigcontext.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The software breakpoint handlers are hooked in directly from ptrace,
which makes it difficult to add additional handlers for things like
kprobes and kgdb.
This patch moves the handling code into debug-monitors.c, where we can
dispatch to different debug subsystems more easily.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Rather than completely killing the kernel if we receive an esr value we
can't deal with in the el0 handlers, send the process a SIGILL and log
the esr value in the hope that we can debug it. If we receive a bad esr
from el1, we'll die() as before.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: stable@vger.kernel.org
Currently user faults (page, undefined instruction) are always reported
even though the user may have a signal handler for them. This patch adds
unhandled_signal() check together with printk_ratelimit() for these
cases.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Both dump_stack() and show_stack() are currently implemented by each
architecture. show_stack(NULL, NULL) dumps the backtrace for the
current task as does dump_stack(). On some archs, dump_stack() prints
extra information - pid, utsname and so on - in addition to the
backtrace while the two are identical on other archs.
The usages in arch-independent code of the two functions indicate
show_stack(NULL, NULL) should print out bare backtrace while
dump_stack() is used for debugging purposes when something went wrong,
so it does make sense to print additional information on the task which
triggered dump_stack().
There's no reason to require archs to implement two separate but mostly
identical functions. It leads to unnecessary subtle information.
This patch expands the dummy fallback dump_stack() implementation in
lib/dump_stack.c such that it prints out debug information (taken from
x86) and invokes show_stack(NULL, NULL) and drops arch-specific
dump_stack() implementations in all archs except blackfin. Blackfin's
dump_stack() does something wonky that I don't understand.
Debug information can be printed separately by calling
dump_stack_print_info() so that arch-specific dump_stack()
implementation can still emit the same debug information. This is used
in blackfin.
This patch brings the following behavior changes.
* On some archs, an extra level in backtrace for show_stack() could be
printed. This is because the top frame was determined in
dump_stack() on those archs while generic dump_stack() can't do that
reliably. It can be compensated by inlining dump_stack() but not
sure whether that'd be necessary.
* Most archs didn't use to print debug info on dump_stack(). They do
now.
An example WARN dump follows.
WARNING: at kernel/workqueue.c:4841 init_workqueues+0x35/0x505()
Hardware name: empty
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.9.0-rc1-work+ #9
0000000000000009 ffff88007c861e08 ffffffff81c614dc ffff88007c861e48
ffffffff8108f50f ffffffff82228240 0000000000000040 ffffffff8234a03c
0000000000000000 0000000000000000 0000000000000000 ffff88007c861e58
Call Trace:
[<ffffffff81c614dc>] dump_stack+0x19/0x1b
[<ffffffff8108f50f>] warn_slowpath_common+0x7f/0xc0
[<ffffffff8108f56a>] warn_slowpath_null+0x1a/0x20
[<ffffffff8234a071>] init_workqueues+0x35/0x505
...
v2: CPU number added to the generic debug info as requested by s390
folks and dropped the s390 specific dump_stack(). This loses %ksp
from the debug message which the maintainers think isn't important
enough to keep the s390-specific dump_stack() implementation.
dump_stack_print_info() is moved to kernel/printk.c from
lib/dump_stack.c. Because linkage is per objecct file,
dump_stack_print_info() living in the same lib file as generic
dump_stack() means that archs which implement custom dump_stack()
- at this point, only blackfin - can't use dump_stack_print_info()
as that will bring in the generic version of dump_stack() too. v1
The v1 patch broke build on blackfin due to this issue. The build
breakage was reported by Fengguang Wu.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> [s390 bits]
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Richard Kuo <rkuo@codeaurora.org> [hexagon bits]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix up all callers as they were before, with make one change: an
unsigned module taints the kernel, but doesn't turn off lockdep.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
The patch contains the exception entry code (kernel/entry.S), pt_regs
structure and related accessors, undefined instruction trapping and
stack tracing.
AArch64 Linux kernel (including kernel threads) runs in EL1 mode using
the SP1 stack. The vectors don't have a fixed address, only alignment
(2^11) requirements.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
