The linker routines that we rely on to produce a relocatable PIE binary
treat it as a shared ELF object in some ways, i.e., it emits symbol based
R_AARCH64_ABS64 relocations into the final binary since doing so would be
appropriate when linking a shared library that is subject to symbol
preemption. (This means that an executable can override certain symbols
that are exported by a shared library it is linked with, and that the
shared library *must* update all its internal references as well, and point
them to the version provided by the executable.)
Symbol preemption does not occur for OS hosted PIE executables, let alone
for vmlinux, and so we would prefer to get rid of these symbol based
relocations. This would allow us to simplify the relocation routines, and
to strip the .dynsym, .dynstr and .hash sections from the binary. (Note
that these are tiny, and are placed in the .init segment, but they clutter
up the vmlinux binary.)
Note that these R_AARCH64_ABS64 relocations are only emitted for absolute
references to symbols defined in the linker script, all other relocatable
quantities are covered by anonymous R_AARCH64_RELATIVE relocations that
simply list the offsets to all 64-bit values in the binary that need to be
fixed up based on the offset between the link time and run time addresses.
Fortunately, GNU ld has a -Bsymbolic option, which is intended for shared
libraries to allow them to ignore symbol preemption, and unconditionally
bind all internal symbol references to its own definitions. So set it for
our PIE binary as well, and get rid of the asoociated sections and the
relocation code that processes them.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
[will: fixed conflict with __dynsym_offset linker script entry]
Signed-off-by: Will Deacon <will.deacon@arm.com>
Due to the untyped KIMAGE_VADDR constant, the linker may not notice
that the __rela_offset and __dynsym_offset expressions are absolute
values (i.e., are not subject to relocation). This does not matter for
KASLR, but it does confuse kallsyms in relative mode, since it uses
the lowest non-absolute symbol address as the anchor point, and expects
all other symbol addresses to be within 4 GB of it.
Fix this by qualifying these expressions as ABSOLUTE() explicitly.
Fixes: 0cd3defe0a ("arm64: kernel: perform relocation processing from ID map")
Cc: <stable@vger.kernel.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Commit 0a8ea52c3e ("arm64: Add HAVE_REGS_AND_STACK_ACCESS_API
feature") inadvertently removed the arch/arm prototype instead of the
arm64 one introduced by the original patch. There should not be any
bisection issues since this function is not called from anywhere else
(it could as well be removed from arch/arm at some point).
Fixes: 0a8ea52c3e ("arm64: Add HAVE_REGS_AND_STACK_ACCESS_API feature")
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Selecting CONFIG_RANDOMIZE_BASE=y and CONFIG_MODULES=n fails to build
the module PLTs support:
CC arch/arm64/kernel/module-plts.o
/work/Linux/linux-2.6-aarch64/arch/arm64/kernel/module-plts.c: In function ‘module_emit_plt_entry’:
/work/Linux/linux-2.6-aarch64/arch/arm64/kernel/module-plts.c:32:49: error: dereferencing pointer to incomplete type ‘struct module’
This patch selects ARM64_MODULE_PLTS conditionally only if MODULES is
enabled.
Fixes: f80fb3a3d5 ("arm64: add support for kernel ASLR")
Cc: <stable@vger.kernel.org> # 4.6+
Reported-by: Jeff Vander Stoep <jeffv@google.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The kernel page table creation routines are accessible to other subsystems
(e.g., EFI) via the create_pgd_mapping() entry point, which allows mappings
to be created that are not covered by init_mm.
Since generic code such as apply_to_page_range() may expect translation
table pages that are not associated with init_mm to be covered by fully
constructed struct pages, add a call to pgtable_page_ctor() in the alloc
function used by create_pgd_mapping. Since it is no longer used by
create_mapping_late(), also update the name of this function to better
reflect its purpose.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Laura Abbott <labbott@redhat.com>
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The only purpose served by create_mapping_late() is to remap the already
mapped .text and .rodata kernel segments with read-only permissions. Since
we no longer allow block mappings to be split or merged,
create_mapping_late() should not pass an allocation function pointer into
__create_pgd_mapping(). So pass NULL instead.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Laura Abbott <labbott@redhat.com>
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* kprobes:
arm64: kprobes: Add KASAN instrumentation around stack accesses
arm64: kprobes: Cleanup jprobe_return
arm64: kprobes: Fix overflow when saving stack
arm64: kprobes: WARN if attempting to step with PSTATE.D=1
kprobes: Add arm64 case in kprobe example module
arm64: Add kernel return probes support (kretprobes)
arm64: Add trampoline code for kretprobes
arm64: kprobes instruction simulation support
arm64: Treat all entry code as non-kprobe-able
arm64: Blacklist non-kprobe-able symbol
arm64: Kprobes with single stepping support
arm64: add conditional instruction simulation support
arm64: Add more test functions to insn.c
arm64: Add HAVE_REGS_AND_STACK_ACCESS_API feature
Passing "nosmp" should boot the kernel with a single processor, without
provision to enable secondary CPUs even if they are present. "nosmp" is
implemented by setting maxcpus=0. At the moment we still mark the secondary
CPUs present even with nosmp, which allows the userspace to bring them
up. This patch corrects the smp_prepare_cpus() to honor the maxcpus == 0.
Commit 44dbcc93ab ("arm64: Fix behavior of maxcpus=N") fixed the
behavior for maxcpus >= 1, but broke maxcpus = 0.
Fixes: 44dbcc93ab ("arm64: Fix behavior of maxcpus=N")
Cc: <stable@vger.kernel.org> # 4.7+
Cc: Will Deacon <will.deacon@arm.com>
Cc: James Morse <james.morse@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
[catalin.marinas@arm.com: updated code comment]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
In smp_prepare_boot_cpu(), we invoke cpuinfo_store_boot_cpu to store
the cpuinfo in a per-cpu ptr, before initialising the per-cpu offset for
the boot CPU. This patch reorders the sequence to make sure we initialise
the per-cpu offset before accessing the per-cpu area.
Commit 4b998ff188 ("arm64: Delay cpuinfo_store_boot_cpu") fixed the
issue where we modified the per-cpu area even before the kernel initialises
the per-cpu areas, but failed to wait until the boot cpu updated it's
offset.
Fixes: 4b998ff188 ("arm64: Delay cpuinfo_store_boot_cpu")
Cc: <stable@vger.kernel.org> # 4.4+
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
jprobe_return seems to have aged badly. Comments referring to
non-existent behaviours, and a dangerous habit of messing
with registers without telling the compiler.
This patches applies the following remedies:
- Fix the comments to describe the actual behaviour
- Tidy up the asm sequence to directly assign the
stack pointer without clobbering extra registers
- Mark the rest of the function as unreachable() so
that the compiler knows that there is no need for
an epilogue
- Stop making jprobe_return_break a global function
(you really don't want to call that guy, and it isn't
even a function).
Tested with tcp_probe.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The MIN_STACK_SIZE macro tries evaluate how much stack space needs
to be saved in the jprobes_stack array, sized at 128 bytes.
When using the IRQ stack, said macro can happily return up to
IRQ_STACK_SIZE, which is 16kB. Mayhem follows.
This patch fixes things by getting rid of the crazy macro and
limiting the copy to be at most the size of the jprobes_stack
array, no matter which stack we're on.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Stepping with PSTATE.D=1 is bad news. The step won't generate a debug
exception and we'll likely walk off into random data structures. This
should never happen, but when it does, it's a PITA to debug. Add a
WARN_ON to shout if we realise this is about to take place.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The debug enable/disable macros are not used anywhere in the kernel, so
remove them from irqflags.h
Reported-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
There is no need to explicitly clear the SS bit immediately before
setting it unconditionally.
Reported-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Clearing PSTATE.D is one of the requirements for generating a debug
exception. The arm64 booting protocol requires that PSTATE.D is set,
since many of the debug registers (for example, the hw_breakpoint
registers) are UNKNOWN out of reset and could potentially generate
spurious, fatal debug exceptions in early boot code if PSTATE.D was
clear. Once the debug registers have been safely initialised, PSTATE.D
is cleared, however this is currently broken for two reasons:
(1) The boot CPU clears PSTATE.D in a postcore_initcall and secondary
CPUs clear PSTATE.D in secondary_start_kernel. Since the initcall
runs after SMP (and the scheduler) have been initialised, there is
no guarantee that it is actually running on the boot CPU. In this
case, the boot CPU is left with PSTATE.D set and is not capable of
generating debug exceptions.
(2) In a preemptible kernel, we may explicitly schedule on the IRQ
return path to EL1. If an IRQ occurs with PSTATE.D set in the idle
thread, then we may schedule the kthread_init thread, run the
postcore_initcall to clear PSTATE.D and then context switch back
to the idle thread before returning from the IRQ. The exception
return path will then restore PSTATE.D from the stack, and set it
again.
This patch fixes the problem by moving the clearing of PSTATE.D earlier
to proc.S. This has the desirable effect of clearing it in one place for
all CPUs, long before we have to worry about the scheduler or any
exception handling. We ensure that the previous reset of MDSCR_EL1 has
completed before unmasking the exception, so that any spurious
exceptions resulting from UNKNOWN debug registers are not generated.
Without this patch applied, the kprobes selftests have been seen to fail
under KVM, where we end up attempting to step the OOL instruction buffer
with PSTATE.D set and therefore fail to complete the step.
Cc: <stable@vger.kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Reported-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
We currently define OBJCOPYFLAGS in the top-level arm64 Makefile, and
thus these flags will be passed to all uses of objcopy, kernel-wide, for
which they are not explicitly overridden. The flags we set are intended
for converting vmlinux (and ELF) into Image (a raw binary), and thus the
flags chosen are problematic for some other uses which do not expect a
raw binary result, e.g. the upcoming lkdtm rodata test:
http://www.openwall.com/lists/kernel-hardening/2016/06/08/2
This patch localises the objcopy flags such that they are only used for
the vmlinux -> Image conversion.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Acked-by: Kees Cook <keescook@chromium.org>
Tested-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
...and do not confuse source navigation tools ;)
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Add info prints in sample kprobe handlers for ARM64
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>
The pre-handler of this special 'trampoline' kprobe executes the return
probe handler functions and restores original return address in ELR_EL1.
This way the saved pt_regs still hold the original register context to be
carried back to the probed kernel function.
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>
The trampoline code is used by kretprobes to capture a return from a probed
function. This is done by saving the registers, calling the handler, and
restoring the registers. The code then returns to the original saved caller
return address. It is necessary to do this directly instead of using a
software breakpoint because the code used in processing that breakpoint
could itself be kprobe'd and cause a problematic reentry into the debug
exception handler.
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 unnecessary masking of the PSTATE bits]
Signed-off-by: Catalin Marinas <catalin.marinas@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>
Entry symbols are not kprobe safe. So blacklist them for kprobing.
Signed-off-by: Pratyush Anand <panand@redhat.com>
Signed-off-by: David A. Long <dave.long@linaro.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
[catalin.marinas@arm.com: Do not include syscall wrappers in .entry.text]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Add all function symbols which are called from do_debug_exception under
NOKPROBE_SYMBOL, as they can not kprobed.
Signed-off-by: Pratyush Anand <panand@redhat.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Add support for basic kernel probes(kprobes) and jump probes
(jprobes) for ARM64.
Kprobes utilizes software breakpoint and single step debug
exceptions supported on ARM v8.
A software breakpoint is placed at the probe address to trap the
kernel execution into the kprobe handler.
ARM v8 supports enabling single stepping before the break exception
return (ERET), with next PC in exception return address (ELR_EL1). The
kprobe handler prepares an executable memory slot for out-of-line
execution with a copy of the original instruction being probed, and
enables single stepping. The PC is set to the out-of-line slot address
before the ERET. With this scheme, the instruction is executed with the
exact same register context except for the PC (and DAIF) registers.
Debug mask (PSTATE.D) is enabled only when single stepping a recursive
kprobe, e.g.: during kprobes reenter so that probed instruction can be
single stepped within the kprobe handler -exception- context.
The recursion depth of kprobe is always 2, i.e. upon probe re-entry,
any further re-entry is prevented by not calling handlers and the case
counted as a missed kprobe).
Single stepping from the x-o-l slot has a drawback for PC-relative accesses
like branching and symbolic literals access as the offset from the new PC
(slot address) may not be ensured to fit in the immediate value of
the opcode. Such instructions need simulation, so reject
probing them.
Instructions generating exceptions or cpu mode change are rejected
for probing.
Exclusive load/store instructions are rejected too. Additionally, the
code is checked to see if it is inside an exclusive load/store sequence
(code from Pratyush).
System instructions are mostly enabled for stepping, except MSR/MRS
accesses to "DAIF" flags in PSTATE, which are not safe for
probing.
This also changes arch/arm64/include/asm/ptrace.h to use
include/asm-generic/ptrace.h.
Thanks to Steve Capper and Pratyush Anand for several suggested
Changes.
Signed-off-by: Sandeepa Prabhu <sandeepa.s.prabhu@gmail.com>
Signed-off-by: David A. Long <dave.long@linaro.org>
Signed-off-by: Pratyush Anand <panand@redhat.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
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>
Add HAVE_REGS_AND_STACK_ACCESS_API feature for arm64, including supporting
functions and defines.
Signed-off-by: David A. Long <dave.long@linaro.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
[catalin.marinas@arm.com: Remove unused functions]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
It can be useful for JIT software to be aware of MIDR_EL1 and
REVIDR_EL1 to ascertain the presence of any core errata that could
affect code generation.
This patch exposes these registers through sysfs:
/sys/devices/system/cpu/cpu$ID/regs/identification/midr_el1
/sys/devices/system/cpu/cpu$ID/regs/identification/revidr_el1
where $ID is the cpu number. For big.LITTLE systems, one can have a
mixture of cores (e.g. Cortex A53 and Cortex A57), thus all CPUs need
to be enumerated.
If the kernel does not have valid information to populate these entries
with, an empty string is returned to userspace.
Cc: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Steve Capper <steve.capper@linaro.org>
[suzuki.poulose@arm.com: ABI documentation updates, hotplug notifiers, kobject changes]
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
So far the arm64 clock_gettime() vDSO implementation only supported
the following clocks, falling back to the syscall for the others:
- CLOCK_REALTIME{,_COARSE}
- CLOCK_MONOTONIC{,_COARSE}
This patch adds support for the CLOCK_MONOTONIC_RAW clock, taking
advantage of the recent refactoring of the vDSO time functions. Like
the non-_COARSE clocks, this only works when the "arch_sys_counter"
clocksource is in use (allowing us to read the current time from the
virtual counter register), otherwise we also have to fall back to the
syscall.
Most of the data is shared with CLOCK_MONOTONIC, and the algorithm is
similar. The reference implementation in kernel/time/timekeeping.c
shows that:
- CLOCK_MONOTONIC = tk->wall_to_monotonic + tk->xtime_sec +
timekeeping_get_ns(&tk->tkr_mono)
- CLOCK_MONOTONIC_RAW = tk->raw_time + timekeeping_get_ns(&tk->tkr_raw)
- tkr_mono and tkr_raw are identical (in particular, same
clocksource), except these members:
* mult (only mono's multiplier is NTP-adjusted)
* xtime_nsec (always 0 for raw)
Therefore, tk->raw_time and tkr_raw->mult are now also stored in the
vDSO data page.
Cc: Ali Saidi <ali.saidi@arm.com>
Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Reviewed-by: Dave Martin <dave.martin@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Time functions are directly implemented in assembly in arm64, and it
is desirable to keep it this way for performance reasons (everything
fits in registers, so that the stack is not used at all). However, the
current implementation is quite difficult to read and understand (even
considering it's assembly). Additionally, due to the structure of
__kernel_clock_gettime, which heavily uses conditional branches to
share code between the different clocks, it is difficult to support a
new clock without making the branches even harder to follow.
This commit completely refactors the structure of clock_gettime (and
gettimeofday along the way) while keeping exactly the same algorithms.
We no longer try to share code; instead, macros provide common
operations. This new approach comes with a number of advantages:
- In clock_gettime, clock implementations are no longer interspersed,
making them much more readable. Additionally, macros only use
registers passed as arguments or reserved with .req, this way it is
easy to make sure that registers are properly allocated. To avoid a
large number of branches in a given execution path, a jump table is
used; a normal execution uses 3 unconditional branches.
- __do_get_tspec has been replaced with 2 macros (get_ts_clock_mono,
get_clock_shifted_nsec) and explicit loading of data from the vDSO
page. Consequently, clock_gettime and gettimeofday are now leaf
functions, and saving x30 (lr) is no longer necessary.
- Variables protected by tb_seq_count are now loaded all at once,
allowing to merge the seqcnt_read macro into seqcnt_check.
- For CLOCK_REALTIME_COARSE, removed an unused load of the wall to
monotonic timespec.
- For CLOCK_MONOTONIC_COARSE, removed a few shift instructions.
Obviously, the downside of sharing less code is an increase in code
size. However since the vDSO has its own code page, this does not
really matter, as long as the size of the DSO remains below 4 kB. For
now this should be all right:
Before After
vdso.so size (B) 2776 3000
Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Reviewed-by: Dave Martin <dave.martin@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
arm64/kernel/{vdso,signal}.c include vdso-offsets.h, as well as any
file that includes asm/vdso.h. Therefore, vdso-offsets.h must be
generated before these files are compiled.
The current rules in arm64/kernel/Makefile do not actually enforce
this, because even though $(obj)/vdso is listed as a prerequisite for
vdso-offsets.h, this does not result in the intended effect of
building the vdso subdirectory (before all the other objects). As a
consequence, depending on the order in which the rules are followed,
vdso-offsets.h is updated or not before arm64/kernel/{vdso,signal}.o
are built. The current rules also impose an unnecessary dependency on
vdso-offsets.h for all arm64/kernel/*.o, resulting in unnecessary
rebuilds. This is made obvious when using make -j:
touch arch/arm64/kernel/vdso/gettimeofday.S && make -j$NCPUS arch/arm64/kernel
will sometimes result in none of arm64/kernel/*.o being
rebuilt, sometimes all of them, or even just some of them.
It is quite difficult to ensure that a header is generated before it
is used with recursive Makefiles by using normal rules. Instead,
arch-specific generated headers are normally built in the archprepare
recipe in the arch Makefile (see for instance arch/ia64/Makefile).
Unfortunately, asm-offsets.h is included in gettimeofday.S, and must
therefore be generated before vdso-offsets.h, which is not the case if
archprepare is used. For this reason, a rule run after archprepare has
to be used.
This commit adds rules in arm64/Makefile to build vdso-offsets.h
during the prepare step, ensuring that vdso-offsets.h is generated
before building anything. It also removes the now-unnecessary
dependencies on vdso-offsets.h in arm64/kernel/Makefile. Finally, it
removes the duplication of asm-offsets.h between arm64/kernel/vdso/
and include/generated/ and makes include/generated/vdso-offsets.h a
target in arm64/kernel/vdso/Makefile.
Cc: Will Deacon <will.deacon@arm.com>
Cc: Michal Marek <mmarek@suse.com>
Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This reverts commit 90f777beb7.
While this commit was aimed at fixing the dependencies, with a large
make -j the vdso-offsets.h file is not generated, leading to build
failures.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Current bus notifier in ARM64 (__iommu_attach_notifier)
attempts to attach dma_ops to a device on BUS_NOTIFY_ADD_DEVICE
action notification.
This will cause issues on ACPI based systems, where PCI devices
can be added before the IOMMUs the devices are attached to
had a chance to be probed, causing failures on attempts to
attach dma_ops in that the domain for the respective IOMMU
may not be set-up yet by the time the bus notifier is run.
Devices dma_ops do not require to be set-up till the matching
device drivers are probed. This means that instead of running
the notifier attaching dma_ops to devices (__iommu_attach_notifier)
on BUS_NOTIFY_ADD_DEVICE action, it can be run just before the
device driver is bound to the device in question (on action
BUS_NOTIFY_BIND_DRIVER) so that it is certain that its IOMMU
group and domain are set-up accordingly at the time the
notifier is triggered.
This patch changes the notifier action upon which dma_ops
are attached to devices and defer it to driver binding time,
so that IOMMU devices have a chance to be probed and to register
their bus notifiers before the dma_ops attach sequence for a
device is actually carried out.
As a result we also no longer need worry about racing with
iommu_bus_notifier(), or about retrying the queue in case devices
were added too early on DT-based systems, so clean up the notifier
itself plus the additional workaround from 722ec35f7f ("arm64:
dma-mapping: fix handling of devices registered before arch_initcall")
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
[rm: get rid of other now-redundant bits]
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
On a big-little system, PMUs can be wired to CPUs using per CPU
interrups (PPI). In this case, it is important to make sure that
the enable/disable do happen on the right set of CPUs.
So instead of relying on the interrupt-affinity property, we can
use the actual percpu affinity that DT exposes as part of the
interrupt specifier. The DT binding is also updated to reflect
the fact that the interrupt-affinity property shouldn't be used
in that case.
Acked-by: Rob Herring <robh@kernel.org>
Tested-by: Caesar Wang <wxt@rock-chips.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
arch/arm64/kernel/{vdso,signal}.c include generated/vdso-offsets.h, and
therefore the symbol offsets must be generated before these files are
compiled.
The current rules in arm64/kernel/Makefile do not actually enforce
this, because even though $(obj)/vdso is listed as a prerequisite for
vdso-offsets.h, this does not result in the intended effect of
building the vdso subdirectory (before all the other objects). As a
consequence, depending on the order in which the rules are followed,
vdso-offsets.h is updated or not before arm64/kernel/{vdso,signal}.o
are built. The current rules also impose an unnecessary dependency on
vdso-offsets.h for all arm64/kernel/*.o, resulting in unnecessary
rebuilds.
This patch removes the arch/arm64/kernel/vdso/vdso-offsets.h file
generation, leaving only the include/generated/vdso-offsets.h one. It
adds a forced dependency check of the vdso-offsets.h file in
arch/arm64/kernel/Makefile which, if not up to date according to the
arch/arm64/kernel/vdso/Makefile rules (depending on vdso.so.dbg), will
trigger the vdso/ subdirectory build and vdso-offsets.h re-generation.
Automatic kbuild dependency rules between kernel/{vdso,signal}.c rules
and vdso-offsets.h will guarantee that the vDSO object is built first,
followed by the generated symbol offsets header file.
Reported-by: Kevin Brodsky <kevin.brodsky@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The routine __create_pgd_mapping() does nothing except calling init_pgd(),
which has no other callers. So fold the latter into the former. Also, drop
a comment that has gone stale.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Since the efi_create_mapping() no longer generates block mappings
and being the last user of the split_p*d code, remove these functions
and the corresponding TLBI.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
[ardb: replace 'overlapping regions' with 'block mappings' in commit log]
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
When running the OS with a page size > 4 KB, we need to round up mappings
for regions that are not aligned to the OS's page size. We already avoid
block mappings for EfiRuntimeServicesCode/Data regions for other reasons,
but in the unlikely event that other unaliged regions exists that have the
EFI_MEMORY_RUNTIME attribute set, ensure that unaligned regions are always
mapped down to pages. This way, the overlapping page is guaranteed not to
be covered by a block mapping that needs to be split.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
To avoid triggering diagnostics in the MMU code that are finicky about
splitting block mappings into more granular mappings, ensure that regions
that are likely to appear in the Memory Attributes table as well as the
UEFI memory map are always mapped down to pages. This way, we can use
apply_to_page_range() instead of create_pgd_mapping() for the second pass,
which cannot split or merge block entries, and operates strictly on PTEs.
Note that this aligns the arm64 Memory Attributes table handling code with
the ARM code, which already uses apply_to_page_range() to set the strict
permissions.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Add a bool parameter 'allow_block_mappings' to create_pgd_mapping() and
the various helper functions that it descends into, to give the caller
control over whether block entries may be used to create the mapping.
The UEFI runtime mapping routines will use this to avoid creating block
entries that would need to split up into page entries when applying the
permissions listed in the Memory Attributes firmware table.
This also replaces the block_mappings_allowed() helper function that was
added for DEBUG_PAGEALLOC functionality, but the resulting code is
functionally equivalent (given that debug_page_alloc does not operate on
EFI page table entries anyway)
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@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>
Currently we call the (optional) enable function for CPU _features_
only. As CPU _errata_ descriptions share the same data structure and
having an enable function is useful for errata as well (for instance
to set bits in SCTLR), lets call it when enumerating erratas too.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The newly introduced dcache_by_line_op macro is used at least in
one occassion at the moment to issue a "dc cvau" instruction,
which is affected by ARM errata 819472, 826319, 827319 and 824069.
Change the macro to allow for alternative patching in there to
protect affected Cortex-A53 cores.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
[catalin.marinas@arm.com: indentation fixups]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The ARM errata 819472, 826319, 827319 and 824069 for affected
Cortex-A53 cores demand to promote "dc cvau" instructions to
"dc civac" as well.
Attribute the usage of the instruction in __flush_cache_user_range
to also be covered by our alternative patching efforts.
For that we introduce an assembly macro which both deals with
alternatives while still tagging the instructions as USER.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Commit 77ee306c0a ("arm64: alternatives: add enable parameter to
conditional asm macros") extended the alternative assembly macros.
Unfortunately this does not really work as one would expect, as the
enable parameter in fact correctly protects the alternative section
magic, but not the actual code sequences.
This results in having both the original instruction(s) _and_ the
alternative ones, if enable if false.
Since there is no user of this macros anyway, just revert it.
This reverts commit 77ee306c0a.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The memblock_alloc() and memblock_alloc_base() will panic on their own
if no free memory, remove pointless BUG_ON.
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
As Kees Cook notes in the ARM counterpart of this patch [0]:
The _etext position is defined to be the end of the kernel text code,
and should not include any part of the data segments. This interferes
with things that might check memory ranges and expect executable code
up to _etext.
In particular, Kees is referring to the HARDENED_USERCOPY patch set [1],
which rejects attempts to call copy_to_user() on kernel ranges containing
executable code, but does allow access to the .rodata segment. Regardless
of whether one may or may not agree with the distinction, it makes sense
for _etext to have the same meaning across architectures.
So let's put _etext where it belongs, between .text and .rodata, and fix
up existing references to use __init_begin instead, which unlike _end_rodata
includes the exception and notes sections as well.
The _etext references in kaslr.c are left untouched, since its references
to [_stext, _etext) are meant to capture potential jump instruction targets,
and so disregarding .rodata is actually an improvement here.
[0] http://article.gmane.org/gmane.linux.kernel/2245084
[1] http://thread.gmane.org/gmane.linux.kernel.hardened.devel/2502
Reported-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
We currently open-code extracting the NUMA node of a memblock region,
which requires an ifdef to cater for !CONFIG_NUMA builds where the
memblock_region::nid field does not exist.
The generic memblock_get_region_node helper is intended to cater for
this. For CONFIG_HAVE_MEMBLOCK_NODE_MAP, builds this returns reg->nid,
and for for !CONFIG_HAVE_MEMBLOCK_NODE_MAP builds this is a static
inline that returns 0. Note that for arm64,
CONFIG_HAVE_MEMBLOCK_NODE_MAP is selected iff CONFIG_NUMA is.
This patch makes use of memblock_get_region_node to simplify the arm64
code. At the same time, we can move the nid variable definition into the
loop, as this is the only place it is used.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Steve Capper <steve.capper@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
