Commit 38fd94b027 ("arm64: Work around Falkor erratum 1003") tried to
work around a hardware erratum, but actually caused a system crash of
its own during switch_mm:
cpu_do_switch_mm+0x20/0x40
efi_virtmap_load+0x34/0x40
virt_efi_get_next_variable+0x64/0xc8
efivar_init+0x8c/0x348
efisubsys_init+0xd4/0x270
do_one_initcall+0x80/0x110
kernel_init_freeable+0x19c/0x240
kernel_init+0x10/0x100
ret_from_fork+0x10/0x50
Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
In cpu_do_switch_mm, x1 contains the mm_struct pointer, which needs to
be preserved by the pre_ttbr0_update_workaround macro rather than passed
as a temporary.
This patch clobbers x2 and x3 instead, keeping the mm_struct intact
after the workaround has run.
Fixes: 38fd94b027 ("arm64: Work around Falkor erratum 1003")
Tested-by: Manoj Iyer <manoj.iyer@canonical.com>
Signed-off-by: Shanker Donthineni <shankerd@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
The Qualcomm Datacenter Technologies Falkor v1 CPU may allocate TLB entries
using an incorrect ASID when TTBRx_EL1 is being updated. When the erratum
is triggered, page table entries using the new translation table base
address (BADDR) will be allocated into the TLB using the old ASID. All
circumstances leading to the incorrect ASID being cached in the TLB arise
when software writes TTBRx_EL1[ASID] and TTBRx_EL1[BADDR], a memory
operation is in the process of performing a translation using the specific
TTBRx_EL1 being written, and the memory operation uses a translation table
descriptor designated as non-global. EL2 and EL3 code changing the EL1&0
ASID is not subject to this erratum because hardware is prohibited from
performing translations from an out-of-context translation regime.
Consider the following pseudo code.
write new BADDR and ASID values to TTBRx_EL1
Replacing the above sequence with the one below will ensure that no TLB
entries with an incorrect ASID are used by software.
write reserved value to TTBRx_EL1[ASID]
ISB
write new value to TTBRx_EL1[BADDR]
ISB
write new value to TTBRx_EL1[ASID]
ISB
When the above sequence is used, page table entries using the new BADDR
value may still be incorrectly allocated into the TLB using the reserved
ASID. Yet this will not reduce functionality, since TLB entries incorrectly
tagged with the reserved ASID will never be hit by a later instruction.
Based on work by Shanker Donthineni <shankerd@codeaurora.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Christopher Covington <cov@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@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>
When returning from idle, we rely on the fact that thread_info lives at
the end of the kernel stack, and restore this by masking the saved stack
pointer. Subsequent patches will sever the relationship between the
stack and thread_info, and to cater for this we must save/restore sp_el0
explicitly, storing it in cpu_suspend_ctx.
As cpu_suspend_ctx must be doubleword aligned, this leaves us with an
extra slot in cpu_suspend_ctx. We can use this to save/restore tpidr_el1
in the same way, which simplifies the code, avoiding pointer chasing on
the restore path (as we no longer need to load thread_info::cpu followed
by the relevant slot in __per_cpu_offset based on this).
This patch stashes both registers in cpu_suspend_ctx.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Cc: James Morse <james.morse@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
- Support for execute-only page permissions
- Support for hibernate and DEBUG_PAGEALLOC
- Support for heterogeneous systems with mismatches cache line sizes
- Errata workarounds (A53 843419 update and QorIQ A-008585 timer bug)
- arm64 PMU perf updates, including cpumasks for heterogeneous systems
- Set UTS_MACHINE for building rpm packages
- Yet another head.S tidy-up
- Some cleanups and refactoring, particularly in the NUMA code
- Lots of random, non-critical fixes across the board
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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:
"It's a bit all over the place this time with no "killer feature" to
speak of. Support for mismatched cache line sizes should help people
seeing whacky JIT failures on some SoCs, and the big.LITTLE perf
updates have been a long time coming, but a lot of the changes here
are cleanups.
We stray outside arch/arm64 in a few areas: the arch/arm/ arch_timer
workaround is acked by Russell, the DT/OF bits are acked by Rob, the
arch_timer clocksource changes acked by Marc, CPU hotplug by tglx and
jump_label by Peter (all CC'd).
Summary:
- Support for execute-only page permissions
- Support for hibernate and DEBUG_PAGEALLOC
- Support for heterogeneous systems with mismatches cache line sizes
- Errata workarounds (A53 843419 update and QorIQ A-008585 timer bug)
- arm64 PMU perf updates, including cpumasks for heterogeneous systems
- Set UTS_MACHINE for building rpm packages
- Yet another head.S tidy-up
- Some cleanups and refactoring, particularly in the NUMA code
- Lots of random, non-critical fixes across the board"
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (100 commits)
arm64: tlbflush.h: add __tlbi() macro
arm64: Kconfig: remove SMP dependence for NUMA
arm64: Kconfig: select OF/ACPI_NUMA under NUMA config
arm64: fix dump_backtrace/unwind_frame with NULL tsk
arm/arm64: arch_timer: Use archdata to indicate vdso suitability
arm64: arch_timer: Work around QorIQ Erratum A-008585
arm64: arch_timer: Add device tree binding for A-008585 erratum
arm64: Correctly bounds check virt_addr_valid
arm64: migrate exception table users off module.h and onto extable.h
arm64: pmu: Hoist pmu platform device name
arm64: pmu: Probe default hw/cache counters
arm64: pmu: add fallback probe table
MAINTAINERS: Update ARM PMU PROFILING AND DEBUGGING entry
arm64: Improve kprobes test for atomic sequence
arm64/kvm: use alternative auto-nop
arm64: use alternative auto-nop
arm64: alternative: add auto-nop infrastructure
arm64: lse: convert lse alternatives NOP padding to use __nops
arm64: barriers: introduce nops and __nops macros for NOP sequences
arm64: sysreg: replace open-coded mrs_s/msr_s with {read,write}_sysreg_s
...
Make use of the new alternative_if and alternative_else_nop_endif and
get rid of our homebew NOP sleds, making the code simpler to read.
Note that for cpu_do_switch_mm the ret has been moved out of the
alternative sequence, and in the default case there will be three
additional NOPs executed.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Changes to make the resume from cpu_suspend() code behave more like
secondary boot caused debug exceptions to be unmasked early by
__cpu_setup(). We then go on to restore mdscr_el1 in cpu_do_resume(),
potentially taking break or watch points based on uninitialised registers.
Mask debug exceptions in cpu_do_resume(), which is specific to resume
from cpu_suspend(). Debug exceptions will be restored to their original
state by local_dbg_restore() in cpu_suspend(), which runs after
hw_breakpoint_restore() has re-initialised the other registers.
Reported-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Fixes: cabe1c81ea ("arm64: Change cpu_resume() to enable mmu early then access sleep_sp by va")
Cc: <stable@vger.kernel.org> # 4.7+
Signed-off-by: James Morse <james.morse@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@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>
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>
By enabling the MMU early in cpu_resume(), the sleep_save_sp and stack can
be accessed by VA, which avoids the need to convert-addresses and clean to
PoC on the suspend path.
MMU setup is shared with the boot path, meaning the swapper_pg_dir is
restored directly: ttbr1_el1 is no longer saved/restored.
struct sleep_save_sp is removed, replacing it with a single array of
pointers.
cpu_do_{suspend,resume} could be further reduced to not restore: cpacr_el1,
mdscr_el1, tcr_el1, vbar_el1 and sctlr_el1, all of which are set by
__cpu_setup(). However these values all contain res0 bits that may be used
to enable future features.
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-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>
On ThunderX T88 pass 1.x through 2.1 parts, broadcast TLBI
instructions may cause the icache to become corrupted if it contains
data for a non-current ASID.
This patch implements the workaround (which invalidates the local
icache when switching the mm) by using code patching.
Signed-off-by: Andrew Pinski <apinski@cavium.com>
Signed-off-by: David Daney <david.daney@cavium.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
If page tables are modified without suitable TLB maintenance, the ARM
architecture permits multiple TLB entries to be allocated for the same
VA. When this occurs, it is permitted that TLB conflict aborts are
raised in response to synchronous data/instruction accesses, and/or and
amalgamation of the TLB entries may be used as a result of a TLB lookup.
The presence of conflicting TLB entries may result in a variety of
behaviours detrimental to the system (e.g. erroneous physical addresses
may be used by I-cache fetches and/or page table walks). Some of these
cases may result in unexpected changes of hardware state, and/or result
in the (asynchronous) delivery of SError.
To avoid these issues, we must avoid situations where conflicting
entries may be allocated into TLBs. For user and module mappings we can
follow a strict break-before-make approach, but this cannot work for
modifications to the swapper page tables that cover the kernel text and
data.
Instead, this patch adds code which is intended to be executed from the
idmap, which can safely unmap the swapper page tables as it only
requires the idmap to be active. This enables us to uninstall the active
TTBR1_EL1 entry, invalidate TLBs, then install a new TTBR1_EL1 entry
without potentially unmapping code or data required for the sequence.
This avoids the risk of conflict, but requires that updates are staged
in a copy of the swapper page tables prior to being installed.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Jeremy Linton <jeremy.linton@arm.com>
Cc: Laura Abbott <labbott@fedoraproject.org>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The Performance Monitors extension is an optional feature of the
AArch64 architecture, therefore, in order to access Performance
Monitors registers safely, the kernel should detect the architected
PMU unit presence through the ID_AA64DFR0_EL1 register PMUVer field
before accessing them.
This patch implements a guard by reading the ID_AA64DFR0_EL1 register
PMUVer field to detect the architected PMU presence and prevent accessing
PMU system registers if the Performance Monitors extension is not
implemented in the core.
Cc: Peter Maydell <peter.maydell@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: <stable@vger.kernel.org>
Fixes: 60792ad349 ("arm64: kernel: enforce pmuserenr_el0 initialization and restore")
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Will Deacon <will.deacon@arm.com>
- Support for the CPU PMU in Cortex-A72
- Add sysfs entries to describe the architected events and their
mappings for PMUv{1-3}
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Merge tag 'arm64-perf' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm[64] perf updates from Will Deacon:
"In the past, I have funnelled perf updates through the respective
architecture trees, but now that the arm/arm64 perf driver has been
largely consolidated under drivers/perf/, it makes more sense to send
a separate pull, particularly as I'm listed as maintainer for all the
files involved. I offered the branch to arm-soc, but Arnd suggested
that I just send it to you directly.
So, here is the arm/arm64 perf queue for 4.5. The main features are
described below, but the most useful change is from Drew, which
advertises our architected event mapping in sysfs so that the perf
tool is a lot more user friendly and no longer requires the use of
magic hex constants for profiling common events.
- Support for the CPU PMU in Cortex-A72
- Add sysfs entries to describe the architected events and their
mappings for PMUv{1-3}"
* tag 'arm64-perf' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
arm64: perf: add support for Cortex-A72
arm64: perf: add format entry to describe event -> config mapping
ARM: perf: add format entry to describe event -> config mapping
arm64: kernel: enforce pmuserenr_el0 initialization and restore
arm64: perf: Correct Cortex-A53/A57 compatible values
arm64: perf: Add event descriptions
arm64: perf: Convert event enums to #defines
arm: perf: Add event descriptions
arm: perf: Convert event enums to #defines
drivers/perf: kill armpmu_register
The pmuserenr_el0 register value is architecturally UNKNOWN on reset.
Current kernel code resets that register value iff the core pmu device is
correctly probed in the kernel. On platforms with missing DT pmu nodes (or
disabled perf events in the kernel), the pmu is not probed, therefore the
pmuserenr_el0 register is not reset in the kernel, which means that its
value retains the reset value that is architecturally UNKNOWN (system
may run with eg pmuserenr_el0 == 0x1, which means that PMU counters access
is available at EL0, which must be disallowed).
This patch adds code that resets pmuserenr_el0 on cold boot and restores
it on core resume from shutdown, so that the pmuserenr_el0 setup is
always enforced in the kernel.
Cc: <stable@vger.kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
We drop __cpu_setup in .text.init, which ends up being part of .text.
The .text.init section was a legacy section name which has been unused
elsewhere for a long time.
The ".text.init" name is misleading if read as a synonym for
".init.text". Any CPU may execute __cpu_setup before turning the MMU on,
so it should simply live in .text.
Remove the pointless section assignment. This will leave __cpu_setup in
the .text section.
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>
- "genirq: Introduce generic irq migration for cpu hotunplugged" patch
merged from tip/irq/for-arm to allow the arm64-specific part to be
upstreamed via the arm64 tree
- CPU feature detection reworked to cope with heterogeneous systems
where CPUs may not have exactly the same features. The features
reported by the kernel via internal data structures or ELF_HWCAP are
delayed until all the CPUs are up (and before user space starts)
- Support for 16KB pages, with the additional bonus of a 36-bit VA
space, though the latter only depending on EXPERT
- Implement native {relaxed, acquire, release} atomics for arm64
- New ASID allocation algorithm which avoids IPI on roll-over, together
with TLB invalidation optimisations (using local vs global where
feasible)
- KASan support for arm64
- EFI_STUB clean-up and isolation for the kernel proper (required by
KASan)
- copy_{to,from,in}_user optimisations (sharing the memcpy template)
- perf: moving arm64 to the arm32/64 shared PMU framework
- L1_CACHE_BYTES increased to 128 to accommodate Cavium hardware
- Support for the contiguous PTE hint on kernel mapping (16 consecutive
entries may be able to use a single TLB entry)
- Generic CONFIG_HZ now used on arm64
- defconfig updates
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 updates from Catalin Marinas:
- "genirq: Introduce generic irq migration for cpu hotunplugged" patch
merged from tip/irq/for-arm to allow the arm64-specific part to be
upstreamed via the arm64 tree
- CPU feature detection reworked to cope with heterogeneous systems
where CPUs may not have exactly the same features. The features
reported by the kernel via internal data structures or ELF_HWCAP are
delayed until all the CPUs are up (and before user space starts)
- Support for 16KB pages, with the additional bonus of a 36-bit VA
space, though the latter only depending on EXPERT
- Implement native {relaxed, acquire, release} atomics for arm64
- New ASID allocation algorithm which avoids IPI on roll-over, together
with TLB invalidation optimisations (using local vs global where
feasible)
- KASan support for arm64
- EFI_STUB clean-up and isolation for the kernel proper (required by
KASan)
- copy_{to,from,in}_user optimisations (sharing the memcpy template)
- perf: moving arm64 to the arm32/64 shared PMU framework
- L1_CACHE_BYTES increased to 128 to accommodate Cavium hardware
- Support for the contiguous PTE hint on kernel mapping (16 consecutive
entries may be able to use a single TLB entry)
- Generic CONFIG_HZ now used on arm64
- defconfig updates
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (91 commits)
arm64/efi: fix libstub build under CONFIG_MODVERSIONS
ARM64: Enable multi-core scheduler support by default
arm64/efi: move arm64 specific stub C code to libstub
arm64: page-align sections for DEBUG_RODATA
arm64: Fix build with CONFIG_ZONE_DMA=n
arm64: Fix compat register mappings
arm64: Increase the max granular size
arm64: remove bogus TASK_SIZE_64 check
arm64: make Timer Interrupt Frequency selectable
arm64/mm: use PAGE_ALIGNED instead of IS_ALIGNED
arm64: cachetype: fix definitions of ICACHEF_* flags
arm64: cpufeature: declare enable_cpu_capabilities as static
genirq: Make the cpuhotplug migration code less noisy
arm64: Constify hwcap name string arrays
arm64/kvm: Make use of the system wide safe values
arm64/debug: Make use of the system wide safe value
arm64: Move FP/ASIMD hwcap handling to common code
arm64/HWCAP: Use system wide safe values
arm64/capabilities: Make use of system wide safe value
arm64: Delay cpu feature capability checks
...
This patch turns on the 16K page support in the kernel. We
support 48bit VA (4 level page tables) and 47bit VA (3 level
page tables).
With 16K we can map 128 entries using contiguous bit hint
at level 3 to map 2M using single TLB entry.
TODO: 16K supports 32 contiguous entries at level 2 to get us
1G(which is not yet supported by the infrastructure). That should
be a separate patch altogether.
Cc: Will Deacon <will.deacon@arm.com>
Cc: Jeremy Linton <jeremy.linton@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Christoffer Dall <christoffer.dall@linaro.org>
Cc: Steve Capper <steve.capper@linaro.org>
Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Our current switch_mm implementation suffers from a number of problems:
(1) The ASID allocator relies on IPIs to synchronise the CPUs on a
rollover event
(2) Because of (1), we cannot allocate ASIDs with interrupts disabled
and therefore make use of a TIF_SWITCH_MM flag to postpone the
actual switch to finish_arch_post_lock_switch
(3) We run context switch with a reserved (invalid) TTBR0 value, even
though the ASID and pgd are updated atomically
(4) We take a global spinlock (cpu_asid_lock) during context-switch
(5) We use h/w broadcast TLB operations when they are not required
(e.g. in flush_context)
This patch addresses these problems by rewriting the ASID algorithm to
match the bitmap-based arch/arm/ implementation more closely. This in
turn allows us to remove much of the complications surrounding switch_mm,
including the ugly thread flag.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
When cold-booting a CPU, we must invalidate any junk entries from the
local TLB prior to enabling the MMU. This doesn't require broadcasting
within the inner-shareable domain, so de-scope the operation to apply
only to the local CPU.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
We don't want to expose the DCC to userspace, particularly as there is
a kernel console driver for it.
This patch resets mdscr_el1 to disable userspace access to the DCC
registers on the cold boot path.
Signed-off-by: Will Deacon <will.deacon@arm.com>
UEFI spec 2.5 section 2.3.6.1 defines that
EFI_MEMORY_[UC|WC|WT|WB] are possible EFI memory types for
AArch64.
Each of those EFI memory types is mapped to a corresponding
AArch64 memory type. So we need to define PROT_DEVICE_nGnRnE
and PROT_NORMWL_WT additionaly.
MT_NORMAL_WT is defined, and its encoding is added to MAIR_EL1
when initializing the CPU.
Signed-off-by: Jonathan (Zhixiong) Zhang <zjzhang@codeaurora.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1438936621-5215-6-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The arm64 booting document requires that the bootloader has cleaned the
kernel image to the PoC. However, when a CPU re-enters the kernel due to
either a CPU hotplug "on" event or resuming from a low-power state (e.g.
cpuidle), the kernel text may in-fact be dirty at the PoU due to things
like alternative patching or even module loading.
Thanks to I-cache speculation with the MMU off, stale instructions could
be fetched prior to enabling the MMU, potentially leading to crashes
when executing regions of code that have been modified at runtime.
This patch addresses the issue by ensuring that the local I-cache is
invalidated immediately after a CPU has enabled its MMU but before
jumping out of the identity mapping. Any stale instructions fetched from
the PoC will then be discarded and refetched correctly from the PoU.
Patching kernel text executed prior to the MMU being enabled is
prohibited, so the early entry code will always be clean.
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Nobody seems to be producing !SMP systems anymore, so this is just
becoming a source of kernel bugs, particularly if people want to use
coherent DMA with non-shared pages.
This patch forces CONFIG_SMP=y for arm64, removing a modest amount of
code in the process.
Signed-off-by: Will Deacon <will.deacon@arm.com>
The ARMv8.1 architecture extensions introduce support for hardware
updates of the access and dirty information in page table entries. With
TCR_EL1.HA enabled, when the CPU accesses an address with the PTE_AF bit
cleared in the page table, instead of raising an access flag fault the
CPU sets the actual page table entry bit. To ensure that kernel
modifications to the page tables do not inadvertently revert a change
introduced by hardware updates, the exclusive monitor (ldxr/stxr) is
adopted in the pte accessors.
When TCR_EL1.HD is enabled, a write access to a memory location with the
DBM (Dirty Bit Management) bit set in the corresponding pte
automatically clears the read-only bit (AP[2]). Such DBM bit maps onto
the Linux PTE_WRITE bit and to check whether a writable (DBM set) page
is dirty, the kernel tests the PTE_RDONLY bit. In order to allow
read-only and dirty pages, the kernel needs to preserve the software
dirty bit. The hardware dirty status is transferred to the software
dirty bit in ptep_set_wrprotect() (using load/store exclusive loop) and
pte_modify().
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
The documented semantics of flush_cache_all are not possible to provide
for arm64 (short of flushing the entire physical address space by VA),
and there are currently no users; KVM uses VA maintenance exclusively,
cpu_reset is never called, and the only two users outside of arch code
cannot be built for arm64.
While cpu_soft_reset and related functions (which call flush_cache_all)
were thought to be useful for kexec, their current implementations only
serve to mask bugs. For correctness kexec will need to perform
maintenance by VA anyway to account for system caches, line migration,
and other subtleties of the cache architecture. As the extent of this
cache maintenance will be kexec-specific, it should probably live in the
kexec code.
This patch removes flush_cache_all, and related unused components,
preventing further abuse.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Geoff Levand <geoff@infradead.org>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The page size and the number of translation levels, and hence the supported
virtual address range, are build-time configurables on arm64 whose optimal
values are use case dependent. However, in the current implementation, if
the system's RAM is located at a very high offset, the virtual address range
needs to reflect that merely because the identity mapping, which is only used
to enable or disable the MMU, requires the extended virtual range to map the
physical memory at an equal virtual offset.
This patch relaxes that requirement, by increasing the number of translation
levels for the identity mapping only, and only when actually needed, i.e.,
when system RAM's offset is found to be out of reach at runtime.
Tested-by: Laura Abbott <lauraa@codeaurora.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
ARM64_CPU_SUSPEND config option was introduced to make code providing
context save/restore selectable only on platforms requiring power
management capabilities.
Currently ARM64_CPU_SUSPEND depends on the PM_SLEEP config option which
in turn is set by the SUSPEND config option.
The introduction of CPU_IDLE for arm64 requires that code configured
by ARM64_CPU_SUSPEND (context save/restore) should be compiled in
in order to enable the CPU idle driver to rely on CPU operations
carrying out context save/restore.
The ARM64_CPUIDLE config option (ARM64 generic idle driver) is therefore
forced to select ARM64_CPU_SUSPEND, even if there may be (ie PM_SLEEP)
failed dependencies, which is not a clean way of handling the kernel
configuration option.
For these reasons, this patch removes the ARM64_CPU_SUSPEND config option
and makes the context save/restore dependent on CPU_PM, which is selected
whenever either SUSPEND or CPU_IDLE are configured, cleaning up dependencies
in the process.
This way, code previously configured through ARM64_CPU_SUSPEND is
compiled in whenever a power management subsystem requires it to be
present in the kernel (SUSPEND || CPU_IDLE), which is the behaviour
expected on ARM64 kernels.
The cpu_suspend and cpu_init_idle CPU operations are added only if
CPU_IDLE is selected, since they are CPU_IDLE specific methods and
should be grouped and defined accordingly.
PSCI CPU operations are updated to reflect the introduced changes.
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
We initialise the SCTLR_EL1 value by read-modify-writeback
of the desired bits, leaving the other bits (including reserved
bits(RESx)) untouched. However, sometimes the boot monitor could
leave garbage values in the RESx bits which could have different
implications. This patch makes sure that all the bits, including
the RESx bits, are set to the proper state, except for the
'endianness' control bits, EE(25) & E0E(24)- which are set early
in the el2_setup.
Updated the state of the Bit[6] in the comment to RES0 in the
comment.
Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The current soft_restart() and setup_restart implementations incorrectly
assume that compiler will not spill/fill values to/from stack. However
this assumption seems to be wrong, revealed by the disassembly of the
currently existing code (v3.16) built with Linaro GCC 4.9-2014.05.
ffffffc000085224 <soft_restart>:
ffffffc000085224: a9be7bfd stp x29, x30, [sp,#-32]!
ffffffc000085228: 910003fd mov x29, sp
ffffffc00008522c: f9000fa0 str x0, [x29,#24]
ffffffc000085230: 94003d21 bl ffffffc0000946b4 <setup_mm_for_reboot>
ffffffc000085234: 94003b33 bl ffffffc000093f00 <flush_cache_all>
ffffffc000085238: 94003dfa bl ffffffc000094a20 <cpu_cache_off>
ffffffc00008523c: 94003b31 bl ffffffc000093f00 <flush_cache_all>
ffffffc000085240: b0003321 adrp x1, ffffffc0006ea000 <reset_devices>
ffffffc000085244: f9400fa0 ldr x0, [x29,#24] ----> spilled addr
ffffffc000085248: f942fc22 ldr x2, [x1,#1528] ----> global memstart_addr
ffffffc00008524c: f0000061 adrp x1, ffffffc000094000 <__inval_cache_range+0x40>
ffffffc000085250: 91290021 add x1, x1, #0xa40
ffffffc000085254: 8b010041 add x1, x2, x1
ffffffc000085258: d2c00802 mov x2, #0x4000000000 // #274877906944
ffffffc00008525c: 8b020021 add x1, x1, x2
ffffffc000085260: d63f0020 blr x1
...
Here the compiler generates memory accesses after the cache is disabled,
loading stale values for the spilled value and global variable. As we cannot
control when the compiler will access memory we must rewrite the
functions in assembly to stash values we need in registers prior to
disabling the cache, avoiding the use of memory.
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Arun Chandran <achandran@mvista.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
In order to ensure ordering and completion of inner-shareable maintenance
instructions (cache and TLB) on AArch64, we can use the -ish suffix to
the dmb and dsb instructions respectively.
This patch updates our low-level cache and tlb maintenance routines to
use the inner-shareable barrier variants where appropriate.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The current TCR register setting in arch/arm64/mm/proc.S assumes that
TCR_EL1.TG* fields are one bit wide and bit 31 is RES1 (reserved, set to
1). With the addition of 16K pages (currently unsupported in the
kernel), the TCR_EL1.TG* fields have been extended to two bits. This
patch updates the corresponding Linux definitions and drops the bit 31
setting in proc.S in favour of the new macros.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Joe Sylve <joe.sylve@gmail.com>
ARMv8 supports a range of physical address bit sizes. The PARange bits
from ID_AA64MMFR0_EL1 register are read during boot-time and the
intermediate physical address size bits are written in the translation
control registers (TCR_EL1 and VTCR_EL2).
There is no change in the VA bits and levels of translation.
Signed-off-by: Radha Mohan Chintakuntla <rchintakuntla@cavium.com>
Reviewed-by: Will Deacon <Will.deacon@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Currently we flush the entire dcache at boot within __cpu_setup, but
this is unnecessary as the booting protocol demands that the dcache is
invalid and off upon entering the kernel. The presence of the cache
flush only serves to hide bugs in bootloaders, and is not safe in the
presence of SMP.
In an SMP boot scenario the CPUs enter coherency outside of the kernel,
and the primary CPU enables its caches before bringing up secondary
CPUs. Therefore if any secondary CPU has an entry in its cache (in
violation of the boot protocol), the primary CPU might snoop it even if
the secondary CPU's cache is disabled. The boot-time cache flush only
serves to hide a firmware bug, and slows down a cpu boot unnecessarily.
This patch removes the unnecessary boot-time cache flush.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
[catalin.marinas@arm.com: make __flush_dcache_all local only]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Fix the function name of comment of cpu_do_switch_mm,
because cpu_do_switch_mm is the correct name.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Power management software requires the kernel to save and restore
CPU registers while going through suspend and resume operations
triggered by kernel subsystems like CPU idle and suspend to RAM.
This patch implements code that provides save and restore mechanism
for the arm v8 implementation. Memory for the context is passed as
parameter to both cpu_do_suspend and cpu_do_resume functions, and allows
the callers to implement context allocation as they deem fit.
The registers that are saved and restored correspond to the registers set
actually required by the kernel to be up and running which represents a
subset of v8 ISA.
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Currently there is no dsb between the tlbi in __cpu_setup and the write
to SCTLR_EL1 which enables the MMU in __turn_mmu_on. This means that the
TLB invalidation is not guaranteed to have completed at the point
address translation is enabled, leading to a number of possible issues
including incorrect translations and TLB conflict faults.
This patch moves the tlbi in __cpu_setup above an existing dsb used to
synchronise I-cache invalidation, ensuring that the TLBs have been
invalidated at the point the MMU is enabled.
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: Catalin Marinas <catalin.marinas@arm.com>
The endianness of memory accesses at EL2 and EL1 are configured by
SCTLR_EL2.EE and SCTLR_EL1.EE respectively. When the kernel is booted,
the state of SCTLR_EL{2,1}.EE is unknown, and thus the kernel must
ensure that they are set before performing any memory accesses.
This patch ensures that SCTLR_EL{2,1} are configured appropriately at
boot for kernels of either endianness.
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Matthew Leach <matthew.leach@arm.com>
[catalin.marinas@arm.com: fix SCTLR_EL1.E0E bit setting in head.S]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
TCR.TBI0 can be used to cause hardware address translation to ignore the
top byte of userspace virtual addresses. Whilst not especially useful in
standard C programs, this can be used by JITs to `tag' pointers with
various pieces of metadata.
This patch enables this bit for AArch64 Linux, and adds a new file to
Documentation/arm64/ which describes some potential caveats when using
tagged virtual addresses.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
During boot, we take the debug OS lock before interrupts are enabled.
This is required to prevent clearing of PSTATE.D on the interrupt entry
path, which could result in spurious debug exceptions before we've got
round to resetting things like the hardware breakpoints registers to a
sane state.
A problem with this approach is that taking the OS lock prevents an
external JTAG debugger from debugging the system, which is especially
irritating during boot, where JTAG debugging can be most useful.
This patch clears mdscr_el1 rather than taking the lock, clearing the
MDE and KDE bits and preventing self-hosted hardware debug exceptions
from occurring.
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: stable@vger.kernel.org
If such bit exists on a given CPU, it must be set by the firmware or
boot-loader prior to starting the kernel (see
Documentation/arm64/booting.txt).
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This patch adds AArch64 CPU specific functionality. It assumes that the
implementation is generic to AArch64 and does not require specific
identification. Different CPU implementations may require the setting of
various ACTLR_EL1 bits but such information is not currently available
and it should ideally be pushed to firmware.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
