[ Upstream commit ca2ef4ffab ]
A kernel built with KASAN && FTRACE_WITH_REGS && !MODULES, produces a
boot-time splat in the bowels of ftrace:
| [ 0.000000] ftrace: allocating 32281 entries in 127 pages
| [ 0.000000] ------------[ cut here ]------------
| [ 0.000000] WARNING: CPU: 0 PID: 0 at kernel/trace/ftrace.c:2019 ftrace_bug+0x27c/0x328
| [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 5.4.0-rc3-00008-g7f08ae53a7e3 #13
| [ 0.000000] Hardware name: linux,dummy-virt (DT)
| [ 0.000000] pstate: 60000085 (nZCv daIf -PAN -UAO)
| [ 0.000000] pc : ftrace_bug+0x27c/0x328
| [ 0.000000] lr : ftrace_init+0x640/0x6cc
| [ 0.000000] sp : ffffa000120e7e00
| [ 0.000000] x29: ffffa000120e7e00 x28: ffff00006ac01b10
| [ 0.000000] x27: ffff00006ac898c0 x26: dfffa00000000000
| [ 0.000000] x25: ffffa000120ef290 x24: ffffa0001216df40
| [ 0.000000] x23: 000000000000018d x22: ffffa0001244c700
| [ 0.000000] x21: ffffa00011bf393c x20: ffff00006ac898c0
| [ 0.000000] x19: 00000000ffffffff x18: 0000000000001584
| [ 0.000000] x17: 0000000000001540 x16: 0000000000000007
| [ 0.000000] x15: 0000000000000000 x14: ffffa00010432770
| [ 0.000000] x13: ffff940002483519 x12: 1ffff40002483518
| [ 0.000000] x11: 1ffff40002483518 x10: ffff940002483518
| [ 0.000000] x9 : dfffa00000000000 x8 : 0000000000000001
| [ 0.000000] x7 : ffff940002483519 x6 : ffffa0001241a8c0
| [ 0.000000] x5 : ffff940002483519 x4 : ffff940002483519
| [ 0.000000] x3 : ffffa00011780870 x2 : 0000000000000001
| [ 0.000000] x1 : 1fffe0000d591318 x0 : 0000000000000000
| [ 0.000000] Call trace:
| [ 0.000000] ftrace_bug+0x27c/0x328
| [ 0.000000] ftrace_init+0x640/0x6cc
| [ 0.000000] start_kernel+0x27c/0x654
| [ 0.000000] random: get_random_bytes called from print_oops_end_marker+0x30/0x60 with crng_init=0
| [ 0.000000] ---[ end trace 0000000000000000 ]---
| [ 0.000000] ftrace faulted on writing
| [ 0.000000] [<ffffa00011bf393c>] _GLOBAL__sub_D_65535_0___tracepoint_initcall_level+0x4/0x28
| [ 0.000000] Initializing ftrace call sites
| [ 0.000000] ftrace record flags: 0
| [ 0.000000] (0)
| [ 0.000000] expected tramp: ffffa000100b3344
This is due to an unfortunate combination of several factors.
Building with KASAN results in the compiler generating anonymous
functions to register/unregister global variables against the shadow
memory. These functions are placed in .text.startup/.text.exit, and
given mangled names like _GLOBAL__sub_{I,D}_65535_0_$OTHER_SYMBOL. The
kernel linker script places these in .init.text and .exit.text
respectively, which are both discarded at runtime as part of initmem.
Building with FTRACE_WITH_REGS uses -fpatchable-function-entry=2, which
also instruments KASAN's anonymous functions. When these are discarded
with the rest of initmem, ftrace removes dangling references to these
call sites.
Building without MODULES implicitly disables STRICT_MODULE_RWX, and
causes arm64's patch_map() function to treat any !core_kernel_text()
symbol as something that can be modified in-place. As core_kernel_text()
is only true for .text and .init.text, with the latter depending on
system_state < SYSTEM_RUNNING, we'll treat .exit.text as something that
can be patched in-place. However, .exit.text is mapped read-only.
Hence in this configuration the ftrace init code blows up while trying
to patch one of the functions generated by KASAN.
We could try to filter out the call sites in .exit.text rather than
initializing them, but this would be inconsistent with how we handle
.init.text, and requires hooking into core bits of ftrace. The behaviour
of patch_map() is also inconsistent today, so instead let's clean that
up and have it consistently handle .exit.text.
This patch teaches patch_map() to handle .exit.text at init time,
preventing the boot-time splat above. The flow of patch_map() is
reworked to make the logic clearer and minimize redundant
conditionality.
Fixes: 3b23e4991f ("arm64: implement ftrace with regs")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Amit Daniel Kachhap <amit.kachhap@arm.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Torsten Duwe <duwe@suse.de>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 579d1b3faa ]
This patch fixes two issues present in the current function for encoding
arm64 logical immediates when using the 32-bit variants of instructions.
First, the code does not correctly reject an all-ones 32-bit immediate,
and returns an undefined instruction encoding.
Second, the code incorrectly rejects some 32-bit immediates that are
actually encodable as logical immediates. The root cause is that the code
uses a default mask of 64-bit all-ones, even for 32-bit immediates.
This causes an issue later on when the default mask is used to fill the
top bits of the immediate with ones, shown here:
/*
* Pattern: 0..01..10..01..1
*
* Fill the unused top bits with ones, and check if
* the result is a valid immediate (all ones with a
* contiguous ranges of zeroes).
*/
imm |= ~mask;
if (!range_of_ones(~imm))
return AARCH64_BREAK_FAULT;
To see the problem, consider an immediate of the form 0..01..10..01..1,
where the upper 32 bits are zero, such as 0x80000001. The code checks
if ~(imm | ~mask) contains a range of ones: the incorrect mask yields
1..10..01..10..0, which fails the check; the correct mask yields
0..01..10..0, which succeeds.
The fix for both issues is to generate a correct mask based on the
instruction immediate size, and use the mask to check for all-ones,
all-zeroes, and values wider than the mask.
Currently, arch/arm64/kvm/va_layout.c is the only user of this function,
which uses 64-bit immediates and therefore won't trigger these bugs.
We tested the new code against llvm-mc with all 1,302 encodable 32-bit
logical immediates and all 5,334 encodable 64-bit logical immediates.
Fixes: ef3935eeeb ("arm64: insn: Add encoder for bitwise operations using literals")
Suggested-by: Will Deacon <will@kernel.org>
Co-developed-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: Luke Nelson <luke.r.nels@gmail.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200508181547.24783-2-luke.r.nels@gmail.com
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
The aarch64_insn_encoding_class[] array contains compile-time constant
data, and is never intentionally modified, so let's mark it as const.
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@kernel.org>
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation this program is
distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details you should have received a copy of the gnu general
public license along with this program if not see http www gnu org
licenses
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 503 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Enrico Weigelt <info@metux.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190602204653.811534538@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Since ARMv8.1 supplement introduced LSE atomic instructions back in 2016,
lets add support for STADD and use that in favor of LDXR / STXR loop for
the XADD mapping if available. STADD is encoded as an alias for LDADD with
XZR as the destination register, therefore add LDADD to the instruction
encoder along with STADD as special case and use it in the JIT for CPUs
that advertise LSE atomics in CPUID register. If immediate offset in the
BPF XADD insn is 0, then use dst register directly instead of temporary
one.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add support for emitting ADR and ADRP instructions so we can switch
over our PLT generation code in a subsequent patch.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Patching kernel instructions at runtime requires other CPUs to undergo
a context synchronisation event via an explicit ISB or an IPI in order
to ensure that the new instructions are visible. This is required even
for "hotpatch" instructions such as NOP and BL, so avoid optimising in
this case and always go via stop_machine() when performing general
patching.
ftrace isn't quite as strict, so it can continue to call the nosync
code directly.
Signed-off-by: Will Deacon <will.deacon@arm.com>
When invalidating the instruction cache for a kernel mapping via
flush_icache_range(), it is also necessary to flush the pipeline for
other CPUs so that instructions fetched into the pipeline before the
I-cache invalidation are discarded. For example, if module 'foo' is
unloaded and then module 'bar' is loaded into the same area of memory,
a CPU could end up executing instructions from 'foo' when branching into
'bar' if these instructions were fetched into the pipeline before 'foo'
was unloaded.
Whilst this is highly unlikely to occur in practice, particularly as
any exception acts as a context-synchronizing operation, following the
letter of the architecture requires us to execute an ISB on each CPU
in order for the new instruction stream to be visible.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
The encoder for ADD/SUB (immediate) can only cope with 12bit
immediates, while there is an encoding for a 12bit immediate shifted
by 12 bits to the left.
Let's fix this small oversight by allowing the LSL_12 bit to be set.
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Add an encoder for the EXTR instruction, which also implements the ROR
variant (where Rn == Rm).
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
We lack a way to encode operations such as AND, ORR, EOR that take
an immediate value. Doing so is quite involved, and is all about
reverse engineering the decoding algorithm described in the
pseudocode function DecodeBitMasks().
This has been tested by feeding it all the possible literal values
and comparing the output with that of GAS.
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
We're missing the a way to generate the encoding of the N immediate,
which is only a single bit used in a number of instruction that take
an immediate.
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
aarch64_insn_write() is used to write an instruction.
As on ARM64 in-memory instructions are always stored
in little-endian order, this function, taking the instruction
opcode in native order, correctly convert it to little-endian
before sending it to an helper function __aarch64_insn_write()
which will do the effective write.
This is all good, but the variable and argument holding the
converted value are not annotated for a little-endian value
but left for native values.
Fix this by adjusting the prototype of the helper and
directly using the result of cpu_to_le32() without passing
by an intermediate variable (which was not a distinct one
but the same as the one holding the native value).
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
The function arch64_insn_read() is used to read an instruction.
On AM64 instructions are always stored in little-endian order
and thus the function correctly do a little-to-native endian
conversion to the value just read.
However, the variable used to hold the value before the conversion
is not declared for a little-endian value but for a native one.
Fix this by using the correct type for the declaration: __le32
Note: This only works because the function reading the value,
probe_kernel_read((), takes a void pointer and void pointers
are endian-agnostic. Otherwise probe_kernel_read() should
also be properly annotated (or worse, need to be specialized).
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
The text patching functions which are invoked from jump_label and kprobes
code are protected against cpu hotplug at the call sites.
Use stop_machine_cpuslocked() to avoid recursion on the cpu hotplug
rwsem. stop_machine_cpuslocked() contains a lockdep assertion to catch any
unprotected callers.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/20170524081549.197070135@linutronix.de
Often all is needed is these small helpers, instead of compiler.h or a
full kprobes.h. This is important for asm helpers, in fact even some
asm/kprobes.h make use of these helpers... instead just keep a generic
asm file with helpers useful for asm code with the least amount of
clutter as possible.
Likewise we need now to also address what to do about this file for both
when architectures have CONFIG_HAVE_KPROBES, and when they do not. Then
for when architectures have CONFIG_HAVE_KPROBES but have disabled
CONFIG_KPROBES.
Right now most asm/kprobes.h do not have guards against CONFIG_KPROBES,
this means most architecture code cannot include asm/kprobes.h safely.
Correct this and add guards for architectures missing them.
Additionally provide architectures that not have kprobes support with
the default asm-generic solution. This lets us force asm/kprobes.h on
the header include/linux/kprobes.h always, but most importantly we can
now safely include just asm/kprobes.h on architecture code without
bringing the full kitchen sink of header files.
Two architectures already provided a guard against CONFIG_KPROBES on its
kprobes.h: sh, arch. The rest of the architectures needed gaurds added.
We avoid including any not-needed headers on asm/kprobes.h unless
kprobes have been enabled.
In a subsequent atomic change we can try now to remove compiler.h from
include/linux/kprobes.h.
During this sweep I've also identified a few architectures defining a
common macro needed for both kprobes and ftrace, that of the definition
of the breakput instruction up. Some refer to this as
BREAKPOINT_INSTRUCTION. This must be kept outside of the #ifdef
CONFIG_KPROBES guard.
[mcgrof@kernel.org: fix arm64 build]
Link: http://lkml.kernel.org/r/CAB=NE6X1WMByuARS4mZ1g9+W=LuVBnMDnh_5zyN0CLADaVh=Jw@mail.gmail.com
[sfr@canb.auug.org.au: fixup for kprobes declarations moving]
Link: http://lkml.kernel.org/r/20170214165933.13ebd4f4@canb.auug.org.au
Link: http://lkml.kernel.org/r/20170203233139.32682-1-mcgrof@kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.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
...
Both of these options are poorly named. The features they provide are
necessary for system security and should not be considered debug only.
Change the names to CONFIG_STRICT_KERNEL_RWX and
CONFIG_STRICT_MODULE_RWX to better describe what these options do.
Signed-off-by: Laura Abbott <labbott@redhat.com>
Acked-by: Jessica Yu <jeyu@redhat.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
__pa_symbol is technically the marcro that should be used for kernel
symbols. Switch to this as a pre-requisite for DEBUG_VIRTUAL which
will do bounds checking.
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Add a helper to extract the register field from a given
instruction.
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>
The opcodes.h drags in a lot of definition from the 32bit port, most
of which is not required at all. Clean things up a bit by moving
the bare minimum of what is required next to the actual users,
and drop the include file.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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>
Follow the example set by x86 in commit 9ccaf77cf0 ("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>
Kprobes needs simulation of instructions that cannot be stepped
from a different memory location, e.g.: those instructions
that uses PC-relative addressing. In simulation, the behaviour
of the instruction is implemented using a copy of pt_regs.
The following instruction categories are simulated:
- All branching instructions(conditional, register, and immediate)
- Literal access instructions(load-literal, adr/adrp)
Conditional execution is limited to branching instructions in
ARM v8. If conditions at PSTATE do not match the condition fields
of opcode, the instruction is effectively NOP.
Thanks to Will Cohen for assorted suggested changes.
Signed-off-by: Sandeepa Prabhu <sandeepa.s.prabhu@gmail.com>
Signed-off-by: William Cohen <wcohen@redhat.com>
Signed-off-by: David A. Long <dave.long@linaro.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
[catalin.marinas@arm.com: removed linux/module.h include]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cease using the arm32 arm_check_condition() function and replace it with
a local version for use in deprecated instruction support on arm64. Also
make the function table used by this available for future use by kprobes
and/or uprobes.
This function is derived from code written by Sandeepa Prabhu.
Signed-off-by: Sandeepa Prabhu <sandeepa.s.prabhu@gmail.com>
Signed-off-by: David A. Long <dave.long@linaro.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Certain instructions are hard to execute correctly out-of-line (as in
kprobes). Test functions are added to insn.[hc] to identify these. The
instructions include any that use PC-relative addressing, change the PC,
or change interrupt masking. For efficiency and simplicity test
functions are also added for small collections of related instructions.
Signed-off-by: David A. Long <dave.long@linaro.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Before restricting virt_to_page() to the linear mapping, ensure that
the text patching code does not use it to resolve references into the
core kernel text, which is mapped in the vmalloc area.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
During code generation, we used to BUG_ON unknown/unsupported encoding
or invalid parameters.
Instead, now we report these as errors and simply return the
instruction AARCH64_BREAK_FAULT. Users of these codegen helpers should
check for and handle this failure condition as appropriate.
Otherwise, unhandled codegen failure will result in trapping at
run-time due to AARCH64_BREAK_FAULT, which is arguably better than a
BUG_ON.
Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When running kprobe test on arm64 rt kernel, it reports the below warning:
root@qemu7:~# modprobe kprobe_example
BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:917
in_atomic(): 0, irqs_disabled(): 128, pid: 484, name: modprobe
CPU: 0 PID: 484 Comm: modprobe Not tainted 4.1.6-rt5 #2
Hardware name: linux,dummy-virt (DT)
Call trace:
[<ffffffc0000891b8>] dump_backtrace+0x0/0x128
[<ffffffc000089300>] show_stack+0x20/0x30
[<ffffffc00061dae8>] dump_stack+0x1c/0x28
[<ffffffc0000bbad0>] ___might_sleep+0x120/0x198
[<ffffffc0006223e8>] rt_spin_lock+0x28/0x40
[<ffffffc000622b30>] __aarch64_insn_write+0x28/0x78
[<ffffffc000622e48>] aarch64_insn_patch_text_nosync+0x18/0x48
[<ffffffc000622ee8>] aarch64_insn_patch_text_cb+0x70/0xa0
[<ffffffc000622f40>] aarch64_insn_patch_text_sync+0x28/0x48
[<ffffffc0006236e0>] arch_arm_kprobe+0x38/0x48
[<ffffffc00010e6f4>] arm_kprobe+0x34/0x50
[<ffffffc000110374>] register_kprobe+0x4cc/0x5b8
[<ffffffbffc002038>] kprobe_init+0x38/0x7c [kprobe_example]
[<ffffffc000084240>] do_one_initcall+0x90/0x1b0
[<ffffffc00061c498>] do_init_module+0x6c/0x1cc
[<ffffffc0000fd0c0>] load_module+0x17f8/0x1db0
[<ffffffc0000fd8cc>] SyS_finit_module+0xb4/0xc8
Convert patch_lock to raw loc kto avoid this issue.
Although the problem is found on rt kernel, the fix should be applicable to
mainline kernel too.
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Yang Shi <yang.shi@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
A little change to patch_map() function,
use set_fixmap_offset() to make code more clear.
Signed-off-by: yalin wang <yalin.wang2010@gmail.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
In order to deal with branches located in alternate sequences,
but pointing to the main kernel text, it is required to extract
the relative displacement encoded in the instruction, and to be
able to update said instruction with a new offset (once it is
known).
For this, we introduce three new helpers:
- aarch64_insn_is_branch_imm is a predicate indicating if the
instruction is an immediate branch
- aarch64_get_branch_offset returns a signed value representing
the byte offset encoded in a branch instruction
- aarch64_set_branch_offset takes an instruction and an offset,
and returns the corresponding updated instruction.
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Patching an instruction sometimes requires extracting the immediate
field from this instruction. To facilitate this, and avoid
potential duplication of code, add aarch64_insn_decode_immediate
as the reciprocal to aarch64_insn_encode_immediate.
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Patch 2f896d5866 ("arm64: use fixmap for text patching") changed
the way we patch the kernel text, using a fixmap when the kernel or
modules are flagged as read only.
Unfortunately, a flaw in the logic makes it fall over when patching
modules without CONFIG_DEBUG_SET_MODULE_RONX enabled:
[...]
[ 32.032636] Call trace:
[ 32.032716] [<fffffe00003da0dc>] __copy_to_user+0x2c/0x60
[ 32.032837] [<fffffe0000099f08>] __aarch64_insn_write+0x94/0xf8
[ 32.033027] [<fffffe000009a0a0>] aarch64_insn_patch_text_nosync+0x18/0x58
[ 32.033200] [<fffffe000009c3ec>] ftrace_modify_code+0x58/0x84
[ 32.033363] [<fffffe000009c4e4>] ftrace_make_nop+0x3c/0x58
[ 32.033532] [<fffffe0000164420>] ftrace_process_locs+0x3d0/0x5c8
[ 32.033709] [<fffffe00001661cc>] ftrace_module_init+0x28/0x34
[ 32.033882] [<fffffe0000135148>] load_module+0xbb8/0xfc4
[ 32.034044] [<fffffe0000135714>] SyS_finit_module+0x94/0xc4
[...]
This is triggered by the use of virt_to_page() on a module address,
which ends to pointing to Nowhereland if you're lucky, or corrupt
your precious data if not.
This patch fixes the logic by mimicking what is done on arm:
- If we're patching a module and CONFIG_DEBUG_SET_MODULE_RONX is set,
use vmalloc_to_page().
- If we're patching the kernel and CONFIG_DEBUG_RODATA is set,
use virt_to_page().
- Otherwise, use the provided address, as we can write to it directly.
Tested on 4.0-rc1 as a KVM guest.
Reported-by: Richard W.M. Jones <rjones@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Laura Abbott <lauraa@codeaurora.org>
Tested-by: Richard W.M. Jones <rjones@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
When kernel text is marked as read only, it cannot be modified directly.
Use a fixmap to modify the text instead in a similar manner to
x86 and arm.
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Kees Cook <keescook@chromium.org>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Changes include:
- Support for alternative instruction patching from Andre
- seccomp from Akashi
- Some AArch32 instruction emulation, required by the Android folks
- Optimisations for exception entry/exit code, cmpxchg, pcpu atomics
- mmu_gather range calculations moved into core code
- EFI updates from Ard, including long-awaited SMBIOS support
- /proc/cpuinfo fixes to align with the format used by arch/arm/
- A few non-critical fixes across the architecture
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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:
"Here's the usual mixed bag of arm64 updates, also including some
related EFI changes (Acked by Matt) and the MMU gather range cleanup
(Acked by you).
Changes include:
- support for alternative instruction patching from Andre
- seccomp from Akashi
- some AArch32 instruction emulation, required by the Android folks
- optimisations for exception entry/exit code, cmpxchg, pcpu atomics
- mmu_gather range calculations moved into core code
- EFI updates from Ard, including long-awaited SMBIOS support
- /proc/cpuinfo fixes to align with the format used by arch/arm/
- a few non-critical fixes across the architecture"
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (70 commits)
arm64: remove the unnecessary arm64_swiotlb_init()
arm64: add module support for alternatives fixups
arm64: perf: Prevent wraparound during overflow
arm64/include/asm: Fixed a warning about 'struct pt_regs'
arm64: Provide a namespace to NCAPS
arm64: bpf: lift restriction on last instruction
arm64: Implement support for read-mostly sections
arm64: compat: align cacheflush syscall with arch/arm
arm64: add seccomp support
arm64: add SIGSYS siginfo for compat task
arm64: add seccomp syscall for compat task
asm-generic: add generic seccomp.h for secure computing mode 1
arm64: ptrace: allow tracer to skip a system call
arm64: ptrace: add NT_ARM_SYSTEM_CALL regset
arm64: Move some head.text functions to executable section
arm64: jump labels: NOP out NOP -> NOP replacement
arm64: add support to dump the kernel page tables
arm64: Add FIX_HOLE to permanent fixed addresses
arm64: alternatives: fix pr_fmt string for consistency
arm64: vmlinux.lds.S: don't discard .exit.* sections at link-time
...
The CP15 barrier instructions (CP15ISB, CP15DSB and CP15DMB) are
deprecated in the ARMv7 architecture, superseded by ISB, DSB and DMB
instructions respectively. Some implementations may provide the
ability to disable the CP15 barriers by disabling the CP15BEN bit in
SCTLR_EL1. If not enabled, the encodings for these instructions become
undefined.
To support legacy software using these instructions, this patch
register hooks to -
* emulate CP15 barriers and warn the user about their use
* toggle CP15BEN in SCTLR_EL1
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>
The SWP instruction was deprecated in the ARMv6 architecture. The
ARMv7 multiprocessing extensions mandate that SWP/SWPB instructions
are treated as undefined from reset, with the ability to enable them
through the System Control Register SW bit. With ARMv8, the option to
enable these instructions through System Control Register was dropped
as well.
To support legacy applications using these instructions, port the
emulation of the SWP and SWPB instructions from the arm port to arm64.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Signed-off-by: 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>
When experimenting with patches to provide kprobes support for aarch64
smp machines would hang when inserting breakpoints into kernel code.
The hangs were caused by a race condition in the code called by
aarch64_insn_patch_text_sync(). The first processor in the
aarch64_insn_patch_text_cb() function would patch the code while other
processors were still entering the function and incrementing the
cpu_count field. This resulted in some processors never observing the
exit condition and exiting the function. Thus, processors in the
system hung.
The first processor to enter the patching function performs the
patching and signals that the patching is complete with an increment
of the cpu_count field. When all the processors have incremented the
cpu_count field the cpu_count will be num_cpus_online()+1 and they
will return to normal execution.
Fixes: ae16480785 arm64: introduce interfaces to hotpatch kernel and module code
Signed-off-by: William Cohen <wcohen@redhat.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Following a recent series of enhancements to the insn code the ARMv8
allnoconfig build has been generating a large number of warnings in the
form of:
arch/arm64/kernel/insn.c:689:8: warning: 'insn' may be used uninitialized in this function [-Wmaybe-uninitialized]
This is because BUG() and related macros can be compiled out so we get
execution paths which normally result in a panic compiling out to noops
instead.
I wasn't able to immediately identify a sensible return value to use in
these cases so just return AARCH64_BREAK_FAULT - this is all "should
never happen" code so hopefully it never has a practical impact.
Signed-off-by: Mark Brown <broonie@kernel.org>
[catalin.marinas@arm.com: AARCH64_BREAK_FAULT definition contributed by Daniel Borkmann]
[catalin.marinas@arm.com: replace return 0 with AARCH64_BREAK_FAULT]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Introduce function to generate logical (shifted register)
instructions.
Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Introduce function to generate data-processing (3 source) instructions.
Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Introduce function to generate data-processing (2 source) instructions.
Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Introduce function to generate data-processing (1 source) instructions.
Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Introduce function to generate add/subtract (shifted register)
instructions.
Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Introduce function to generate move wide (immediate) instructions.
Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Introduce function to generate bitfield instructions.
Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Introduce function to generate add/subtract (immediate) instructions.
Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Mark Rutland