linux-stable.git/arch/arm64/kernel/cpu_errata.c, branch v4.9 Linux kernel stable tree arm64: cpufeature: Schedule enable() calls instead of calling them via IPI 2016-10-20T08:50:53+00:00 James Morse james.morse@arm.com 2016-10-18T10:27:46+00:00 2a6dcb2b5f3e21592ca8dfa198dcce7bec09b020 The enable() call for a cpufeature/errata is called using on_each_cpu(). This issues a cross-call IPI to get the work done. Implicitly, this stashes the running PSTATE in SPSR when the CPU receives the IPI, and restores it when we return. This means an enable() call can never modify PSTATE. To allow PAN to do this, change the on_each_cpu() call to use stop_machine(). This schedules the work on each CPU which allows us to modify PSTATE. This involves changing the protype of all the enable() functions. enable_cpu_capabilities() is called during boot and enables the feature on all online CPUs. This path now uses stop_machine(). CPU features for hotplug'd CPUs are enabled by verify_local_cpu_features() which only acts on the local CPU, and can already modify the running PSTATE as it is called from secondary_start_kernel(). Reported-by: Tony Thompson <anthony.thompson@arm.com> Reported-by: Vladimir Murzin <vladimir.murzin@arm.com> Signed-off-by: James Morse <james.morse@arm.com> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> 
The enable() call for a cpufeature/errata is called using on_each_cpu().
This issues a cross-call IPI to get the work done. Implicitly, this
stashes the running PSTATE in SPSR when the CPU receives the IPI, and
restores it when we return. This means an enable() call can never modify
PSTATE.

To allow PAN to do this, change the on_each_cpu() call to use
stop_machine(). This schedules the work on each CPU which allows
us to modify PSTATE.

This involves changing the protype of all the enable() functions.

enable_cpu_capabilities() is called during boot and enables the feature
on all online CPUs. This path now uses stop_machine(). CPU features for
hotplug'd CPUs are enabled by verify_local_cpu_features() which only
acts on the local CPU, and can already modify the running PSTATE as it
is called from secondary_start_kernel().

Reported-by: Tony Thompson <anthony.thompson@arm.com>
Reported-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
arm64: Work around systems with mismatched cache line sizes 2016-09-09T14:03:29+00:00 Suzuki K Poulose suzuki.poulose@arm.com 2016-09-09T13:07:16+00:00 116c81f427ff6c5380850963e3fb8798cc821d2b 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> 
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>
arm64: Use consistent naming for errata handling 2016-09-09T14:03:28+00:00 Suzuki K Poulose suzuki.poulose@arm.com 2016-09-09T13:07:09+00:00 89ba26458b72422e0a1d85eb729a15220b204458 This is a cosmetic change to rename the functions dealing with the errata work arounds to be more consistent with their naming. 1) check_local_cpu_errata() => update_cpu_errata_workarounds() check_local_cpu_errata() actually updates the system's errata work arounds. So rename it to reflect the same. 2) verify_local_cpu_errata() => verify_local_cpu_errata_workarounds() Use errata_workarounds instead of _errata. Cc: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Andre Przywara <andre.przywara@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> 
This is a cosmetic change to rename the functions dealing with
the errata work arounds to be more consistent with their naming.

1) check_local_cpu_errata() => update_cpu_errata_workarounds()
check_local_cpu_errata() actually updates the system's errata work
arounds. So rename it to reflect the same.

2) verify_local_cpu_errata() => verify_local_cpu_errata_workarounds()
Use errata_workarounds instead of _errata.

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux 2016-07-27T18:16:05+00:00 Linus Torvalds torvalds@linux-foundation.org 2016-07-27T18:16:05+00:00 e831101a73fbc8339ef1d1909dad3ef64f089e70 Pull arm64 updates from Catalin Marinas: - Kexec support for arm64 - Kprobes support - Expose MIDR_EL1 and REVIDR_EL1 CPU identification registers to sysfs - Trapping of user space cache maintenance operations and emulation in the kernel (CPU errata workaround) - Clean-up of the early page tables creation (kernel linear mapping, EFI run-time maps) to avoid splitting larger blocks (e.g. pmds) into smaller ones (e.g. ptes) - VDSO support for CLOCK_MONOTONIC_RAW in clock_gettime() - ARCH_HAS_KCOV enabled for arm64 - Optimise IP checksum helpers - SWIOTLB optimisation to only allocate/initialise the buffer if the available RAM is beyond the 32-bit mask - Properly handle the "nosmp" command line argument - Fix for the initialisation of the CPU debug state during early boot - vdso-offsets.h build dependency workaround - Build fix when RANDOMIZE_BASE is enabled with MODULES off * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (64 commits) arm64: arm: Fix-up the removal of the arm64 regs_query_register_name() prototype arm64: Only select ARM64_MODULE_PLTS if MODULES=y arm64: mm: run pgtable_page_ctor() on non-swapper translation table pages arm64: mm: make create_mapping_late() non-allocating arm64: Honor nosmp kernel command line option arm64: Fix incorrect per-cpu usage for boot CPU 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 arm64: debug: remove unused local_dbg_{enable, disable} macros arm64: debug: remove redundant spsr manipulation arm64: debug: unmask PSTATE.D earlier arm64: localise Image objcopy flags arm64: ptrace: remove extra define for CPSR's E bit 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 ... 
Pull arm64 updates from Catalin Marinas:

 - Kexec support for arm64

 - Kprobes support

 - Expose MIDR_EL1 and REVIDR_EL1 CPU identification registers to sysfs

 - Trapping of user space cache maintenance operations and emulation in
   the kernel (CPU errata workaround)

 - Clean-up of the early page tables creation (kernel linear mapping,
   EFI run-time maps) to avoid splitting larger blocks (e.g.  pmds) into
   smaller ones (e.g.  ptes)

 - VDSO support for CLOCK_MONOTONIC_RAW in clock_gettime()

 - ARCH_HAS_KCOV enabled for arm64

 - Optimise IP checksum helpers

 - SWIOTLB optimisation to only allocate/initialise the buffer if the
   available RAM is beyond the 32-bit mask

 - Properly handle the "nosmp" command line argument

 - Fix for the initialisation of the CPU debug state during early boot

 - vdso-offsets.h build dependency workaround

 - Build fix when RANDOMIZE_BASE is enabled with MODULES off

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (64 commits)
  arm64: arm: Fix-up the removal of the arm64 regs_query_register_name() prototype
  arm64: Only select ARM64_MODULE_PLTS if MODULES=y
  arm64: mm: run pgtable_page_ctor() on non-swapper translation table pages
  arm64: mm: make create_mapping_late() non-allocating
  arm64: Honor nosmp kernel command line option
  arm64: Fix incorrect per-cpu usage for boot CPU
  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
  arm64: debug: remove unused local_dbg_{enable, disable} macros
  arm64: debug: remove redundant spsr manipulation
  arm64: debug: unmask PSTATE.D earlier
  arm64: localise Image objcopy flags
  arm64: ptrace: remove extra define for CPSR's E bit
  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: Enable workaround for Cavium erratum 27456 on thunderx-81xx 2016-07-07T17:35:21+00:00 Ganapatrao Kulkarni gkulkarni@caviumnetworks.com 2016-07-07T04:48:17+00:00 47c459beabe969c6751e2ea8d1f85c5fa1652d6c Cavium erratum 27456 commit 104a0c02e8b1 ("arm64: Add workaround for Cavium erratum 27456") is applicable for thunderx-81xx pass1.0 SoC as well. Adding code to enable to 81xx. Signed-off-by: Ganapatrao Kulkarni <gkulkarni@cavium.com> Reviewed-by: Andrew Pinski <apinski@cavium.com> Signed-off-by: Will Deacon <will.deacon@arm.com> 
Cavium erratum 27456 commit 104a0c02e8b1
("arm64: Add workaround for Cavium erratum 27456")
is applicable for thunderx-81xx pass1.0 SoC as well.
Adding code to enable to 81xx.

Signed-off-by: Ganapatrao Kulkarni <gkulkarni@cavium.com>
Reviewed-by: Andrew Pinski <apinski@cavium.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
arm64: trap userspace "dc cvau" cache operation on errata-affected core 2016-07-01T10:46:00+00:00 Andre Przywara andre.przywara@arm.com 2016-06-28T17:07:32+00:00 7dd01aef055792260287c6708daf75aac3918f66 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 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>
arm64: errata: Calling enable functions for CPU errata too 2016-07-01T10:30:28+00:00 Andre Przywara andre.przywara@arm.com 2016-06-28T17:07:30+00:00 8e2318521bf5837dae093413f81292b59d49d030 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> 
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>
arm64: Verify CPU errata work arounds on hotplugged CPU 2016-04-25T14:14:03+00:00 Suzuki K Poulose suzuki.poulose@arm.com 2016-04-22T11:25:34+00:00 6a6efbb45b7d95c84840010095367eb06a64f342 CPU Errata work arounds are detected and applied to the kernel code at boot time and the data is then freed up. If a new hotplugged CPU requires a work around which was not applied at boot time, there is nothing we can do but simply fail the booting. Cc: Will Deacon <will.deacon@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Andre Przywara <andre.przywara@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> 
CPU Errata work arounds are detected and applied to the
kernel code at boot time and the data is then freed up.
If a new hotplugged CPU requires a work around which
was not applied at boot time, there is nothing we can
do but simply fail the booting.

Cc: Will Deacon <will.deacon@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
arm64: cpufeature: Add scope for capability check 2016-04-25T14:12:21+00:00 Suzuki K Poulose suzuki.poulose@arm.com 2016-04-22T11:25:31+00:00 92406f0cc9e3d5cc77bf3de6d68c9c2373dcd701 Add scope parameter to the arm64_cpu_capabilities::matches(), so that this can be reused for checking the capability on a given CPU vs the system wide. The system uses the default scope associated with the capability for initialising the CPU_HWCAPs and ELF_HWCAPs. Cc: James Morse <james.morse@arm.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Andre Przywara <andre.przywara@arm.com> Cc: Will Deacon <will.deacon@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> 
Add scope parameter to the arm64_cpu_capabilities::matches(), so that
this can be reused for checking the capability on a given CPU vs the
system wide. The system uses the default scope associated with the
capability for initialising the CPU_HWCAPs and ELF_HWCAPs.

Cc: James Morse <james.morse@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Andre Przywara <andre.przywara@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
arm64: Add workaround for Cavium erratum 27456 2016-02-26T15:14:27+00:00 Andrew Pinski apinski@cavium.com 2016-02-25T01:44:57+00:00 104a0c02e8b1936c049e18a6d4e4ab040fb61213 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> 
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>