This patch adds the uaccess macros/functions to disable access to user
space by setting TTBR0_EL1 to a reserved zeroed page. Since the value
written to TTBR0_EL1 must be a physical address, for simplicity this
patch introduces a reserved_ttbr0 page at a constant offset from
swapper_pg_dir. The uaccess_disable code uses the ttbr1_el1 value
adjusted by the reserved_ttbr0 offset.
Enabling access to user is done by restoring TTBR0_EL1 with the value
from the struct thread_info ttbr0 variable. Interrupts must be disabled
during the uaccess_ttbr0_enable code to ensure the atomicity of the
thread_info.ttbr0 read and TTBR0_EL1 write. This patch also moves the
get_thread_info asm macro from entry.S to assembler.h for reuse in the
uaccess_ttbr0_* macros.
Cc: Will Deacon <will.deacon@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This patch takes the errata workaround code out of cpu_do_switch_mm into
a dedicated post_ttbr0_update_workaround macro which will be reused in a
subsequent patch.
Cc: Will Deacon <will.deacon@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Kees Cook <keescook@chromium.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Shortly we will want to load a percpu variable in the return from
userspace path. We can save an instruction by folding the addition of
the percpu offset into the load instruction, and this patch adds a new
helper to do so.
At the same time, we clean up this_cpu_ptr for consistency. As with
{adr,ldr,str}_l, we change the template to take the destination register
first, and name this dst. Secondly, we rename the macro to adr_this_cpu,
following the scheme of adr_l, and matching the newly added
ldr_this_cpu.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
NOP sequences tend to get used for padding out alternative sections
and uarch-specific pipeline flushes in errata workarounds.
This patch adds macros for generating these sequences as both inline
asm blocks, but also as strings suitable for embedding in other asm
blocks directly.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Systems with differing CPU i-cache/d-cache line sizes can cause
problems with the cache management by software when the execution
is migrated from one to another. Usually, the application reads
the cache size on a CPU and then uses that length to perform cache
operations. However, if it gets migrated to another CPU with a smaller
cache line size, things could go completely wrong. To prevent such
cases, always use the smallest cache line size among the CPUs. The
kernel CPU feature infrastructure already keeps track of the safe
value for all CPUID registers including CTR. This patch works around
the problem by :
For kernel, dynamically patch the kernel to read the cache size
from the system wide copy of CTR_EL0.
For applications, trap read accesses to CTR_EL0 (by clearing the SCTLR.UCT)
and emulate the mrs instruction to return the system wide safe value
of CTR_EL0.
For faster access (i.e, avoiding to lookup the system wide value of CTR_EL0
via read_system_reg), we keep track of the pointer to table entry for
CTR_EL0 in the CPU feature infrastructure.
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andre Przywara <andre.przywara@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
On systems with mismatched i/d cache min line sizes, we need to use
the smallest size possible across all CPUs. This will be done by fetching
the system wide safe value from CPU feature infrastructure.
However the some special users(e.g kexec, hibernate) would need the line
size on the CPU (rather than the system wide), when either the system
wide feature may not be accessible or it is guranteed that the caller
executes with a gurantee of no migration.
Provide another helper which will fetch cache line size on the current CPU.
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: James Morse <james.morse@arm.com>
Reviewed-by: Geoff Levand <geoff@infradead.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@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>
Kexec and hibernate need to copy pages of memory, but may not have all
of the kernel mapped, and are unable to call copy_page().
Add a simplistic copy_page() macro, that can be inlined in these
situations. lib/copy_page.S provides a bigger better version, but
uses more registers.
Signed-off-by: Geoff Levand <geoff@infradead.org>
[Changed asm label to 9998, added commit message]
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>
To allow the assembler macros defined in arch/arm64/mm/proc-macros.S to
be used outside the mm code move the contents of proc-macros.S to
asm/assembler.h. Also, delete proc-macros.S, and fix up all references
to proc-macros.S.
Signed-off-by: Geoff Levand <geoff@infradead.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
[rebased, included dcache_by_line_op]
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>
Implement a macro mov_q that can be used to move an immediate constant
into a 64-bit register, using between 2 and 4 movz/movk instructions
(depending on the operand)
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
We haven't used the push/pop macros for a while now, as it's typically
better to use immediate offsets for batches of accesses to the stack, as
we now do in the entry assembly for the kernel and hyp code.
Remove the unused macros.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Instead of using absolute addresses for both the exception location
and the fixup, use offsets relative to the exception table entry values.
Not only does this cut the size of the exception table in half, it is
also a prerequisite for KASLR, since absolute exception table entries
are subject to dynamic relocation, which is incompatible with the sorting
of the exception table that occurs at build time.
This patch also introduces the _ASM_EXTABLE preprocessor macro (which
exists on x86 as well) and its _asm_extable assembly counterpart, as
shorthands to emit exception table entries.
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Unfortunately, the current way of using the linker to emit build time
constants into the Image header will no longer work once we switch to
the use of PIE executables. The reason is that such constants are emitted
into the binary using R_AARCH64_ABS64 relocations, which are resolved at
runtime, not at build time, and the places targeted by those relocations
will contain zeroes before that.
So refactor the endian swapping linker script constant generation code so
that it emits the upper and lower 32-bit words separately.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
irq_stack is a per_cpu variable, that needs to be access from entry.S.
Use an assembler macro instead of the unreadable details.
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
For more control over which functions are called with the MMU off or
with the UEFI 1:1 mapping active, annotate some assembler routines as
position independent. This is done by introducing ENDPIPROC(), which
replaces the ENDPROC() declaration of those routines.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Nobody seems to be producing !SMP systems anymore, so this is just
becoming a source of kernel bugs, particularly if people want to use
coherent DMA with non-shared pages.
This patch forces CONFIG_SMP=y for arm64, removing a modest amount of
code in the process.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Commit 68234df4ea ("arm64: kill flush_cache_all()") removed the
only users of these macros.
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
The adrp instruction is mostly used in combination with either
an add, a ldr or a str instruction with the low bits of the
referenced symbol in the 12-bit immediate of the followup
instruction.
Introduce the macros adr_l, ldr_l and str_l that encapsulate
these common patterns.
Tested-by: Mark Rutland <mark.rutland@arm.com>
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>
asm/assembler.h lacks the usual guard against multiple inclusion,
leading to a compilation failure if it is accidentally included
twice.
Using the classic #ifndef/#define/#endif construct solves the issue.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Since mdscr_el1 is part of the debug register group, it is highly likely
to be trapped by a hypervisor to prevent virtual machines from debugging
(buggering?) each other. Unfortunately, this absolutely destroys our
performance, since we access the register on many of our low-level
fault handling paths to keep track of the various debug state machines.
This patch removes our dependency on mdscr_el1 in the case that debugging
is not being used. More specifically we:
- Use TIF_SINGLESTEP to indicate that a task is stepping at EL0 and
avoid disabling step in the MDSCR when we don't need to.
MDSCR_EL1.SS handling is moved to kernel_entry, when trapping from
userspace.
- Ensure debug exceptions are re-enabled on *all* exception entry
paths, even the debug exception handling path (where we re-enable
exceptions after invoking the handler). Since we can now rely on
MDSCR_EL1.SS being cleared by the entry code, exception handlers can
usually enable debug immediately before enabling interrupts.
- Remove all debug exception unmasking from ret_to_user and
el1_preempt, since we will never get here with debug exceptions
masked.
This results in a slight change to kernel debug behaviour, where we now
step into interrupt handlers and data aborts from EL1 when debugging the
kernel, which is actually a useful thing to do. A side-effect of this is
that it *does* potentially prevent stepping off {break,watch}points when
there is a high-frequency interrupt source (e.g. a timer), so a debugger
would need to use either breakpoints or manually disable interrupts to
get around this issue.
With this patch applied, guest performance is restored under KVM when
debug register accesses are trapped (and we get a measurable performance
increase on the host on Cortex-A57 too).
Cc: Ian Campbell <ian.campbell@citrix.com>
Tested-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>
Add CPU_LE and CPU_BE to select assembler code in little and big
endian configurations respectively.
Signed-off-by: Matthew Leach <matthew.leach@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The arm64 port contains wrappers for arm32 syscalls that pass 64-bit
values. These wrappers concatenate the two registers to hold a 64-bit
value in a single X register. On BE, however, the lower and higher
words are swapped.
Create a new assembler macro, regs_to_64, that when on BE systems
swaps the registers in the orr instruction.
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Matthew Leach <matthew.leach@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
When we take an exception at EL1, we only want to enable debug
exceptions if we're not currently stepping, otherwise we can easily get
stuck in a loop stepping into interrupt handlers.
Unfortunately, the current code tests the wrong bit in the mdscr, so fix
that.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This macro is also useful to other bits defining vectors (hypervisor
stub, KVM...).
Move it to a common location.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This patch introduces several assembly macros and definitions used in
the .S files across arch/arm64/ like IRQ disabling/enabling, together
with asm-offsets.c.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
