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Adds helpers for decoding/encoding the PC relative addresses for adrp.
This will be used for handling dynamic patching of 'adrp' instructions
in alternative code patching.
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
The alternative code patching doesn't check if the replaced instruction
uses a pc relative literal. This could cause silent corruption in the
instruction stream as the instruction will be executed from a different
address than what it was compiled for. Catch all such cases.
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Andre Przywara <andre.przywara@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Suggested-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Right now we run through the work around checks on a CPU
from __cpuinfo_store_cpu. There are some problems with that:
1) We initialise the system wide CPU feature registers only after the
Boot CPU updates its cpuinfo. Now, if a work around depends on the
variance of a CPU ID feature (e.g, check for Cache Line size mismatch),
we have no way of performing it cleanly for the boot CPU.
2) It is out of place, invoked from __cpuinfo_store_cpu() in cpuinfo.c. It
is not an obvious place for that.
This patch rearranges the CPU specific capability(aka work around) checks.
1) At the moment we use verify_local_cpu_capabilities() to check if a new
CPU has all the system advertised features. Use this for the secondary CPUs
to perform the work around check. For that we rename
verify_local_cpu_capabilities() => check_local_cpu_capabilities()
which:
If the system wide capabilities haven't been initialised (i.e, the CPU
is activated at the boot), update the system wide detected work arounds.
Otherwise (i.e a CPU hotplugged in later) verify that this CPU conforms to the
system wide capabilities.
2) Boot CPU updates the work arounds from smp_prepare_boot_cpu() after we have
initialised the system wide CPU feature values.
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>
This is a cosmetic change to rename the functions dealing with
the errata work arounds to be more consistent with their naming.
1) check_local_cpu_errata() => update_cpu_errata_workarounds()
check_local_cpu_errata() actually updates the system's errata work
arounds. So rename it to reflect the same.
2) verify_local_cpu_errata() => verify_local_cpu_errata_workarounds()
Use errata_workarounds instead of _errata.
Cc: Mark Rutland <mark.rutland@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>
Right now we use 0 as the safe value for CTR_EL0:L1Ip, which is
not defined at the moment. The safer value for the L1Ip should be
the weakest of the policies, which happens to be AIVIVT. While at it,
fix the comment about safe_val.
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
1. Remove the old binding code.
2. Read the nid of cpu0 from dts.
3. Fallback the nid of cpu0 to 0 when numa=off is set in bootargs.
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
numa_init may return error because of numa configuration error. So "No
NUMA configuration found" is inaccurate. In fact, specific configuration
error information should be immediately printed by the testing branch.
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
By using a common attr_groups array, the common arm_pmu code can set up
common files (e.g. cpumask) for us in subsequent patches.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
A while back we added {read,write}_sysreg accessors to handle accesses
to system registers, without the usual boilerplate asm volatile,
temporary variable, etc.
This patch makes use of these across arm64 to make code shorter and
clearer. For sequences with a trailing ISB, the existing isb() macro is
also used so that asm blocks can be removed entirely.
A few uses of inline assembly for msr/mrs are left as-is. Those
manipulating sp_el0 for the current thread_info value have special
clobber requiremends.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
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 adds static keys transparently for all the cpu_hwcaps
features by implementing an array of default-false static keys and
enabling them when detected. The cpus_have_cap() check uses the static
keys if the feature being checked is a constant, otherwise the compiler
generates the bitmap test.
Because of the early call to static_branch_enable() via
check_local_cpu_errata() -> update_cpu_capabilities(), the jump labels
are initialised in cpuinfo_store_boot_cpu().
Cc: Will Deacon <will.deacon@arm.com>
Cc: Suzuki K. Poulose <Suzuki.Poulose@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Currently, enabling stacktrace of a kprobe events generates warning:
echo stacktrace > /sys/kernel/debug/tracing/trace_options
echo "p xhci_irq" > /sys/kernel/debug/tracing/kprobe_events
echo 1 > /sys/kernel/debug/tracing/events/kprobes/enable
save_stack_trace_regs() not implemented yet.
------------[ cut here ]------------
WARNING: CPU: 1 PID: 0 at ../kernel/stacktrace.c:74 save_stack_trace_regs+0x3c/0x48
Modules linked in:
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.8.0-rc4-dirty #5128
Hardware name: ARM Juno development board (r1) (DT)
task: ffff800975dd1900 task.stack: ffff800975ddc000
PC is at save_stack_trace_regs+0x3c/0x48
LR is at save_stack_trace_regs+0x3c/0x48
pc : [<ffff000008126c64>] lr : [<ffff000008126c64>] pstate: 600003c5
sp : ffff80097ef52c00
Call trace:
save_stack_trace_regs+0x3c/0x48
__ftrace_trace_stack+0x168/0x208
trace_buffer_unlock_commit_regs+0x5c/0x7c
kprobe_trace_func+0x308/0x3d8
kprobe_dispatcher+0x58/0x60
kprobe_breakpoint_handler+0xbc/0x18c
brk_handler+0x50/0x90
do_debug_exception+0x50/0xbc
This patch implements save_stack_trace_regs(), so that stacktrace of a
kprobe events can be obtained.
After this patch, there is no warning and we can see the stacktrace for
kprobe events in trace buffer.
more /sys/kernel/debug/tracing/trace
<idle>-0 [004] d.h. 1356.000496: p_xhci_irq_0:(xhci_irq+0x0/0x9ac)
<idle>-0 [004] d.h. 1356.000497: <stack trace>
=> xhci_irq
=> __handle_irq_event_percpu
=> handle_irq_event_percpu
=> handle_irq_event
=> handle_fasteoi_irq
=> generic_handle_irq
=> __handle_domain_irq
=> gic_handle_irq
=> el1_irq
=> arch_cpu_idle
=> default_idle_call
=> cpu_startup_entry
=> secondary_start_kernel
=>
Tested-by: David A. Long <dave.long@linaro.org>
Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: Pratyush Anand <panand@redhat.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Commit b5fe242972ef ("arm64: kernel: fix style issues in sleep.S")
changed the linkage of _cpu_resume() to local, even though the symbol
is also referenced from hibernate.c. So revert this change.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Single-step traps to userspace (e.g. via ptrace) are expected to use
the TRAP_TRACE for the si_code field of the siginfo, as opposed to
TRAP_HWBRPT that we report currently.
Fix the reported value, which has no effect on existing and legacy
builds of GDB.
Reported-by: Yao Qi <yao.qi@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Now that the only remaining occurrences of the use of callee saved
registers are on the primary boot path, add a comment to the code
which register is used for what.
Reviewed-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>
Instead of stashing the value of the link register in x28 before setting
up the stack and calling into C code, create an ordinary PCS compatible
stack frame so that we can push the return address onto the stack.
Since exception handlers require a stack as well, assign the stack pointer
register before installing the vector table.
Note that this accounts for the difference between THREAD_START_SP and
THREAD_SIZE, given that the stack pointer is always decremented before
calling into any C code.
Reviewed-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>
Keeping __PHYS_OFFSET in x24 is actually less clear than simply taking
the value of __PHYS_OFFSET using an adrp instruction in the three places
that we need it. So change that.
Reviewed-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>
Using x27 for passing to __enable_mmu what is essentially the return
address makes the code look more complicated than it needs to be. So
switch to x30/lr, and update the secondary and cpu_resume call sites to
simply call __enable_mmu as an ordinary function, with a bl instruction.
This requires the callers to be covered by .idmap.text.
Reviewed-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 KASLR processing is only used by the primary boot path, and
complements the processing that takes place in __primary_switch().
Move the two parts together, to make the code easier to understand.
Also, fix up a minor whitespace issue.
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
[will: fixed conflict with -rc3 due to lack of fd363bd417dd]
Signed-off-by: Will Deacon <will.deacon@arm.com>
The function el2_setup() passes its return value in register w20, and
in the two cases where the caller actually cares about this return value,
it is passed into set_cpu_boot_mode_flag() [almost] directly, which
expects its input in w20 as well.
So there is no reason to use a 'special' callee saved register here, but
we can simply follow the PCS for return value and first argument,
respectively.
Reviewed-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>
This fixes a number of style issues in sleep.S. No functional changes are
intended:
- replace absolute literal references with relative references in
__cpu_suspend_enter(), which executes from its virtual address
- replace explicit lr assignment plus branch with bl in cpu_resume(), which
aligns it with stext() and secondary_startup()
- don't export _cpu_resume()
- use adr_l for mpidr_hash reference, and fix the incorrect accompanying
comment, which has been out of date since commit cabe1c81ea5be983 ("arm64:
Change cpu_resume() to enable mmu early then access sleep_sp by va")
- replace leading spaces with tabs, and add a bit of whitespace for
readability
Reviewed-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>
Commit e19a6ee2460b ("arm64: kernel: Save and restore UAO and
addr_limit on exception entry") states that exception handler inherits
the original PSTATE.UAO value, so UAO needes to be reset
explicitly. However, ARM 8.2 Extension documentation says:
PSTATE.UAO is copied to SPSR_ELx.UAO and is then set to 0 on an
exception taken from AArch64 to AArch64
so hardware already does the right thing.
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Acked-by: James Morse <james.morse@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
The arm64 debug monitor initialisation code uses a CPU hotplug notifier
to clear the OS lock when CPUs come online.
This patch converts the code to the new hotplug mechanism.
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
The arm64 hw_breakpoint implementation uses a CPU hotplug notifier to
reset the {break,watch}point registers when CPUs come online.
This patch converts the code to the new hotplug mechanism, whilst moving
the invocation earlier to remove the need to disable IRQs explicitly in
the driver (which could cause havok if we trip a watchpoint in an IRQ
handler whilst restoring the debug register state).
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
When TIF_SINGLESTEP is set for a task, the single-step state machine is
enabled and we must take care not to reset it to the active-not-pending
state if it is already in the active-pending state.
Unfortunately, that's exactly what user_enable_single_step does, by
unconditionally setting the SS bit in the SPSR for the current task.
This causes failures in the GDB testsuite, where GDB ends up missing
expected step traps if the instruction being stepped generates another
trap, e.g. PTRACE_EVENT_FORK from an SVC instruction.
This patch fixes the problem by preserving the current state of the
stepping state machine when TIF_SINGLESTEP is set on the current thread.
Cc: <stable@vger.kernel.org>
Reported-by: Yao Qi <yao.qi@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Expose the arm64_ftr_reg struct covering CTR_EL0 outside of cpufeature.o
so that other code can refer to it directly (i.e., without performing the
binary search)
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Constify the arm64_ftr_regs array, by moving the mutable arm64_ftr_reg
fields out of the array itself. This also streamlines the bsearch, since
the entire array can be covered by fewer cachelines. Moving the payload
out of the array also allows us to have special explicitly defined
struct instance in case other code needs to refer to it directly.
Note that this replaces the runtime sorting of the array with a runtime
BUG() check whether the array is sorted correctly in the code.
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
The arm64_ftr_bits structures are never modified, so make them read-only.
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
The make rpm target depends on proper UTS_MACHINE definition. Also, use
the variable in arch/arm64/kernel/setup.c, so that it's not accidentally
removed in the future.
Reported-and-tested-by: Fabian Vogt <fvogt@suse.com>
Signed-off-by: Michal Marek <mmarek@suse.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Now that we use the MPIDR to resume on the same CPU that we hibernated on,
we no longer need to refuse to hibernate if the boot cpu is offline. (Which
we can't possibly know if kexec causes logical CPUs to be renumbered).
This reverts commit 1fe492ce6482b77807b25d29690a48c46456beee.
Signed-off-by: James Morse <james.morse@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
disable_nonboot_cpus() assumes that the lowest numbered online CPU is
the boot CPU, and that this is the correct CPU to run any power
management code on.
On arm64 CPU0 can be taken offline. For hibernate/resume this means we
may hibernate on a CPU other than CPU0. If the system is rebooted with
kexec 'CPU0' will be assigned to a different CPU. This complicates
hibernate/resume as now we can't trust the CPU numbers.
We currently forbid hibernate if CPU0 has been hotplugged out to avoid
this situation without kexec.
Save the MPIDR of the CPU we hibernated on in the hibernate arch-header,
use hibernate_resume_nonboot_cpu_disable() to direct which CPU we should
resume on based on the MPIDR of the CPU we hibernated on. This allows us to
hibernate/resume on any CPU, even if the logical numbers have been
shuffled by kexec.
Signed-off-by: James Morse <james.morse@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Follow the example set by x86 in commit 9ccaf77cf05915f5 ("x86/mm:
Always enable CONFIG_DEBUG_RODATA and remove the Kconfig option"), and
make these protections a fundamental security feature rather than an
opt-in. This also results in a minor code simplification.
For those rare cases when users wish to disable this protection (e.g.
for debugging), this can be done by passing 'rodata=off' on the command
line.
As DEBUG_RODATA_ALIGN is only intended to address a performance/memory
tradeoff, and does not affect correctness, this is left user-selectable.
DEBUG_MODULE_RONX is also left user-selectable until the core code
provides a boot-time option to disable the protection for debugging
use-cases.
Cc: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Kdump(kexec-tools) parses /proc/iomem to identify all the memory regions
on the system. Since the current kernel names "nomap" regions, like UEFI
runtime services code/data, as "System RAM," kexec-tools sets up elf core
header to include them in a crash dump file (/proc/vmcore).
Then crash dump kernel parses UEFI memory map again, re-marks those regions
as "nomap" and does not create a memory mapping for them unlike the other
areas of System RAM. In this case, copying /proc/vmcore through
copy_oldmem_page() on crash dump kernel will end up with a kernel abort,
as reported in [1].
This patch names all the "nomap" regions explicitly as "reserved" so that
we can exclude them from a crash dump file. acpi_os_ioremap() must also
be modified because those regions have WB attributes [2].
Apart from kdump, this change also matches x86's use of acpi (and
/proc/iomem).
[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2016-August/448186.html
[2] http://lists.infradead.org/pipermail/linux-arm-kernel/2016-August/450089.html
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: James Morse <james.morse@arm.com>
Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
DEBUG_PAGEALLOC removes the valid bit of page table entries to prevent
any access to unallocated memory. Hibernate uses this as a hint that those
pages don't need to be saved/restored. This patch adds the
kernel_page_present() function it uses.
hibernate.c copies the resume kernel's linear map for use during restore.
Add _copy_pte() to fill-in the holes made by DEBUG_PAGEALLOC in the resume
kernel, so we can restore data the original kernel had at these addresses.
Finally, DEBUG_PAGEALLOC means the linear-map alias of KERNEL_START to
KERNEL_END may have holes in it, so we can't lazily clean this whole
area to the PoC. Only clean the new mmuoff region, and the kernel/kvm
idmaps.
This reverts commit da24eb1f3f9e2c7b75c5f8c40d8e48e2c4789596.
Reported-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Resume from hibernate needs to clean any text executed by the kernel with
the MMU off to the PoC. Collect these functions together into the
.idmap.text section as all this code is tightly coupled and also needs
the same cleaning after resume.
Data is more complicated, secondary_holding_pen_release is written with
the MMU on, clean and invalidated, then read with the MMU off. In contrast
__boot_cpu_mode is written with the MMU off, the corresponding cache line
is invalidated, so when we read it with the MMU on we don't get stale data.
These cache maintenance operations conflict with each other if the values
are within a Cache Writeback Granule (CWG) of each other.
Collect the data into two sections .mmuoff.data.read and .mmuoff.data.write,
the linker script ensures mmuoff.data.write section is aligned to the
architectural maximum CWG of 2KB.
Signed-off-by: James Morse <james.morse@arm.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Each time new section markers are added, kernel/vmlinux.ld.S is updated,
and new extern char __start_foo[] definitions are scattered through the
tree.
Create asm/include/sections.h to collect these definitions (and include
the existing asm-generic version).
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Whenever we are hitting a kprobe from a none-kprobe debug exception handler,
we hit an infinite occurrences of "Unexpected kernel single-step exception
at EL1"
PSTATE.D is debug exception mask bit. It is set whenever we enter into an
exception mode. When it is set then Watchpoint, Breakpoint, and Software
Step exceptions are masked. However, software Breakpoint Instruction
exceptions can never be masked. Therefore, if we ever execute a BRK
instruction, irrespective of D-bit setting, we will be receiving a
corresponding breakpoint exception.
For example:
- We are executing kprobe pre/post handler, and kprobe has been inserted in
one of the instruction of a function called by handler. So, it executes
BRK instruction and we land into the case of KPROBE_REENTER. (This case is
already handled by current code)
- We are executing uprobe handler or any other BRK handler such as in
WARN_ON (BRK BUG_BRK_IMM), and we trace that path using kprobe.So, we
enter into kprobe breakpoint handler,from another BRK handler.(This case
is not being handled currently)
In all such cases kprobe breakpoint exception will be raised when we were
already in debug exception mode. SPSR's D bit (bit 9) shows the value of
PSTATE.D immediately before the exception was taken. So, in above example
cases we would find it set in kprobe breakpoint handler. Single step
exception will always be followed by a kprobe breakpoint exception.However,
it will only be raised gracefully if we clear D bit while returning from
breakpoint exception. If D bit is set then, it results into undefined
exception and when it's handler enables dbg then single step exception is
generated, however it will never be handled(because address does not match
and therefore treated as unexpected).
This patch clears D-flag unconditionally in setup_singlestep, so that we can
always get single step exception correctly after returning from breakpoint
exception. Additionally, it also removes D-flag set statement for
KPROBE_REENTER return path, because debug exception for KPROBE_REENTER will
always take place in a debug exception state. So, D-flag will already be set
in this case.
Acked-by: Sandeepa Prabhu <sandeepa.s.prabhu@gmail.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Pratyush Anand <panand@redhat.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Currently, x25 and x26 hold the physical addresses of idmap_pg_dir
and swapper_pg_dir, respectively, when running early boot code. But
having registers with 'global' scope in files that contain different
sections with different lifetimes, and that are called by different
CPUs at different times is a bit messy, especially since stashing the
values does not buy us anything in terms of code size or clarity.
So simply replace each reference to x25 or x26 with an adrp instruction
referring to idmap_pg_dir or swapper_pg_dir directly.
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>
These objects are set during initialization, thereafter are read only.
Previously I only want to mark vdso_pages, vdso_spec, vectors_page and
cpu_ops as __read_mostly from performance point of view. Then inspired
by Kees's patch[1] to apply more __ro_after_init for arm, I think it's
better to mark them as __ro_after_init. What's more, I find some more
objects are also read only after init. So apply __ro_after_init to all
of them.
This patch also removes global vdso_pagelist and tries to clean up
vdso_spec[] assignment code.
[1] http://www.spinics.net/lists/arm-kernel/msg523188.html
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
The vm_special_mapping spec which is used for aarch32 vectors page is
never modified, so mark it as const.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
It is not needed after booting, this patch moves the alloc_vectors_page
function to the __init section.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Use the builtin_platform_driver() to simplify code.
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Currently ret_fast_syscall, work_pending, and ret_to_user form an ad-hoc
state machine that can be difficult to reason about due to duplicated
code and a large number of branch targets.
This patch factors the common logic out into the existing
do_notify_resume function, converting the code to C in the process,
making the code more legible.
This patch tries to closely mirror the existing behaviour while using
the usual C control flow primitives. As local_irq_{disable,enable} may
be instrumented, we balance exception entry (where we will almost most
likely enable IRQs) with a call to trace_hardirqs_on just before the
return to userspace.
Signed-off-by: Chris Metcalf <cmetcalf@mellanox.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
In break_before_make_ttbr_switch we perform broadcast TLB maintenance
for the inner shareable domain, and use a DSB ISH to complete this.
However, at the point we execute this, secondary CPUs are either
physically offline, or executing code outside of the kernel. Upon
entering the kernel, secondary CPUs will invalidate their TLBs before
enabling their MMUs.
Thus we do not need to invalidate TLBs of other CPUs, and as with
idmap_cpu_replace_ttbr1 we can reduce the scope of maintenance to the
TLBs of the local CPU. This keeps our TLB maintenance code consistent,
and is a minor optimisation.
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: James Morse <james.morse@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Literal loads of virtual addresses are subject to runtime relocation when
CONFIG_RELOCATABLE=y, and given that the relocation routines run with the
MMU and caches enabled, literal loads of relocated values performed with
the MMU off are not guaranteed to return the latest value unless the
memory covering the literal is cleaned to the PoC explicitly.
So defer the literal load until after the MMU has been enabled, just like
we do for primary_switch() and secondary_switch() in head.S.
Fixes: 1e48ef7fcc37 ("arm64: add support for building vmlinux as a relocatable PIE binary")
Cc: <stable@vger.kernel.org> # 4.6+
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
In create_safe_exec_page(), we create a copy of the hibernate exit text,
along with some page tables to map this via TTBR0. We then install the
new tables in TTBR0.
In swsusp_arch_resume() we call create_safe_exec_page() before trying a
number of operations which may fail (e.g. copying the linear map page
tables). If these fail, we bail out of swsusp_arch_resume() and return
an error code, but leave TTBR0 as-is. Subsequently, the core hibernate
code will call free_basic_memory_bitmaps(), which will free all of the
memory allocations we made, including the page tables installed in
TTBR0.
Thus, we may have TTBR0 pointing at dangling freed memory for some
period of time. If the hibernate attempt was triggered by a user
requesting a hibernate test via the reboot syscall, we may return to
userspace with the clobbered TTBR0 value.
Avoid these issues by reorganising swsusp_arch_resume() such that we
have no failure paths after create_safe_exec_page(). We also add a check
that the zero page allocation succeeded, matching what we have for other
allocations.
Fixes: 82869ac57b5d ("arm64: kernel: Add support for hibernate/suspend-to-disk")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: James Morse <james.morse@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: <stable@vger.kernel.org> # 4.7+
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
In create_safe_exec_page we install a set of global mappings in TTBR0,
then subsequently invalidate TLBs. While TTBR0 points at the zero page,
and the TLBs should be free of stale global entries, we may have stale
ASID-tagged entries (e.g. from the EFI runtime services mappings) for
the same VAs. Per the ARM ARM these ASID-tagged entries may conflict
with newly-allocated global entries, and we must follow a
Break-Before-Make approach to avoid issues resulting from this.
This patch reworks create_safe_exec_page to invalidate TLBs while the
zero page is still in place, ensuring that there are no potential
conflicts when the new TTBR0 value is installed. As a single CPU is
online while this code executes, we do not need to perform broadcast TLB
maintenance, and can call local_flush_tlb_all(), which also subsumes
some barriers. The remaining assembly is converted to use write_sysreg()
and isb().
Other than this, we safely manipulate TTBRs in the hibernate dance. The
code we install as part of the new TTBR0 mapping (the hibernated
kernel's swsusp_arch_suspend_exit) installs a zero page into TTBR1,
invalidates TLBs, then installs its preferred value. Upon being restored
to the middle of swsusp_arch_suspend, the new image will call
__cpu_suspend_exit, which will call cpu_uninstall_idmap, installing the
zero page in TTBR0 and invalidating all TLB entries.
Fixes: 82869ac57b5d ("arm64: kernel: Add support for hibernate/suspend-to-disk")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: James Morse <james.morse@arm.com>
Tested-by: James Morse <james.morse@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: <stable@vger.kernel.org> # 4.7+
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Executing from a non-executable area gives an ugly message:
lkdtm: Performing direct entry EXEC_RODATA
lkdtm: attempting ok execution at ffff0000084c0e08
lkdtm: attempting bad execution at ffff000008880700
Bad mode in Synchronous Abort handler detected on CPU2, code 0x8400000e -- IABT (current EL)
CPU: 2 PID: 998 Comm: sh Not tainted 4.7.0-rc2+ #13
Hardware name: linux,dummy-virt (DT)
task: ffff800077e35780 ti: ffff800077970000 task.ti: ffff800077970000
PC is at lkdtm_rodata_do_nothing+0x0/0x8
LR is at execute_location+0x74/0x88
The 'IABT (current EL)' indicates the error but it's a bit cryptic
without knowledge of the ARM ARM. There is also no indication of the
specific address which triggered the fault. The increase in kernel
page permissions makes hitting this case more likely as well.
Handling the case in the vectors gives a much more familiar looking
error message:
lkdtm: Performing direct entry EXEC_RODATA
lkdtm: attempting ok execution at ffff0000084c0840
lkdtm: attempting bad execution at ffff000008880680
Unable to handle kernel paging request at virtual address ffff000008880680
pgd = ffff8000089b2000
[ffff000008880680] *pgd=00000000489b4003, *pud=0000000048904003, *pmd=0000000000000000
Internal error: Oops: 8400000e [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 997 Comm: sh Not tainted 4.7.0-rc1+ #24
Hardware name: linux,dummy-virt (DT)
task: ffff800077f9f080 ti: ffff800008a1c000 task.ti: ffff800008a1c000
PC is at lkdtm_rodata_do_nothing+0x0/0x8
LR is at execute_location+0x74/0x88
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Because the arm64 calling standard allows stacked function arguments to be
anywhere in the stack frame, do not attempt to duplicate the stack frame for
jprobes handler functions.
Documentation changes to describe this issue have been broken out into a
separate patch in order to simultaneously address them in other
architecture(s).
Signed-off-by: David A. Long <dave.long@linaro.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Enable the hard limit of cpu count by set boot options nr_cpus=x
on arm64, and make a minor change about message when total number
of cpu exceeds the limit.
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reported-by: Shiyuan Hu <hushiyuan@huawei.com>
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
- Fix HugeTLB leak due to CoW and PTE_RDONLY mismatch
- Avoid accessing unmapped FDT fields when checking validity
- Correctly account for vDSO AUX entry in ARCH_DLINFO
- Fix kallsyms with absolute expressions in linker script
- Kill unnecessary symbol-based relocs in vmlinux
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Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 fixes from Will Deacon:
- fix HugeTLB leak due to CoW and PTE_RDONLY mismatch
- avoid accessing unmapped FDT fields when checking validity
- correctly account for vDSO AUX entry in ARCH_DLINFO
- fix kallsyms with absolute expressions in linker script
- kill unnecessary symbol-based relocs in vmlinux
* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
arm64: Fix copy-on-write referencing in HugeTLB
arm64: mm: avoid fdt_check_header() before the FDT is fully mapped
arm64: Define AT_VECTOR_SIZE_ARCH for ARCH_DLINFO
arm64: relocatable: suppress R_AARCH64_ABS64 relocations in vmlinux
arm64: vmlinux.lds: make __rela_offset and __dynsym_offset ABSOLUTE
