linux.git/Documentation/arm64, branch v4.12 Linux kernel source tree arm64: documentation: document tagged pointer stack constraints 2017-05-09T16:43:18+00:00 Kristina Martsenko kristina.martsenko@arm.com 2017-05-03T15:37:48+00:00 f0e421b1bf7af97f026e1bb8bfe4c5a7a8c08f42 Some kernel features don't currently work if a task puts a non-zero address tag in its stack pointer, frame pointer, or frame record entries (FP, LR). For example, with a tagged stack pointer, the kernel can't deliver signals to the process, and the task is killed instead. As another example, with a tagged frame pointer or frame records, perf fails to generate call graphs or resolve symbols. For now, just document these limitations, instead of finding and fixing everything that doesn't work, as it's not known if anyone needs to use tags in these places anyway. In addition, as requested by Dave Martin, generalize the limitations into a general kernel address tag policy, and refactor tagged-pointers.txt to include it. Fixes: d50240a5f6ce ("arm64: mm: permit use of tagged pointers at EL0") Cc: <stable@vger.kernel.org> # 3.12.x- Reviewed-by: Dave Martin <Dave.Martin@arm.com> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> 
Some kernel features don't currently work if a task puts a non-zero
address tag in its stack pointer, frame pointer, or frame record entries
(FP, LR).

For example, with a tagged stack pointer, the kernel can't deliver
signals to the process, and the task is killed instead. As another
example, with a tagged frame pointer or frame records, perf fails to
generate call graphs or resolve symbols.

For now, just document these limitations, instead of finding and fixing
everything that doesn't work, as it's not known if anyone needs to use
tags in these places anyway.

In addition, as requested by Dave Martin, generalize the limitations
into a general kernel address tag policy, and refactor
tagged-pointers.txt to include it.

Fixes: d50240a5f6ce ("arm64: mm: permit use of tagged pointers at EL0")
Cc: <stable@vger.kernel.org> # 3.12.x-
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Merge tag 'arch-timer-errata-prereq' of git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms into for-next/core 2017-04-07T16:04:19+00:00 Catalin Marinas catalin.marinas@arm.com 2017-04-07T16:04:19+00:00 a5a3237e508e51fb63373ceafa0b45651cacbc55 Pre-requisites for the arch timer errata workarounds: - Allow checking of a CPU-local erratum - Add CNTVCT_EL0 trap handler - Define Cortex-A73 MIDR - Allow an erratum to be match for all revisions of a core - Add capability to advertise Cortex-A73 erratum 858921 * tag 'arch-timer-errata-prereq' of git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms: arm64: cpu_errata: Add capability to advertise Cortex-A73 erratum 858921 arm64: cpu_errata: Allow an erratum to be match for all revisions of a core arm64: Define Cortex-A73 MIDR arm64: Add CNTVCT_EL0 trap handler arm64: Allow checking of a CPU-local erratum 
Pre-requisites for the arch timer errata workarounds:

- Allow checking of a CPU-local erratum
- Add CNTVCT_EL0 trap handler
- Define Cortex-A73 MIDR
- Allow an erratum to be match for all revisions of a core
- Add capability to advertise Cortex-A73 erratum 858921

* tag 'arch-timer-errata-prereq' of git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms:
  arm64: cpu_errata: Add capability to advertise Cortex-A73 erratum 858921
  arm64: cpu_errata: Allow an erratum to be match for all revisions of a core
  arm64: Define Cortex-A73 MIDR
  arm64: Add CNTVCT_EL0 trap handler
  arm64: Allow checking of a CPU-local erratum
arm64: cpu_errata: Add capability to advertise Cortex-A73 erratum 858921 2017-04-07T10:22:08+00:00 Marc Zyngier marc.zyngier@arm.com 2017-03-20T17:18:06+00:00 eeb1efbcb83c0cfe6d567abbacd675bbddf3d658 In order to work around Cortex-A73 erratum 858921 in a subsequent patch, add the required capability that advertise the erratum. As the configuration option it depends on is not present yet, this has no immediate effect. Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> 
In order to work around Cortex-A73 erratum 858921 in a subsequent
patch, add the required capability that advertise the erratum.

As the configuration option it depends on is not present yet,
this has no immediate effect.

Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
arm64: v8.3: Support for weaker release consistency 2017-03-20T16:30:22+00:00 Suzuki K Poulose suzuki.poulose@arm.com 2017-03-14T18:13:27+00:00 c651aae5a7732287c1c9bc974ece4ed798780544 ARMv8.3 adds new instructions to support Release Consistent processor consistent (RCpc) model, which is weaker than the RCsc model. Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> 
ARMv8.3 adds new instructions to support Release Consistent
processor consistent (RCpc) model, which is weaker than the
RCsc model.

Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
arm64: v8.3: Support for complex number instructions 2017-03-20T16:30:08+00:00 Suzuki K Poulose suzuki.poulose@arm.com 2017-03-14T18:13:26+00:00 cb567e79fa504575cb97fb2f866d2040ed1c92e7 ARM v8.3 adds support for new instructions to aid floating-point multiplication and addition of complex numbers. Expose the support via HWCAP and MRS emulation Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> 
ARM v8.3 adds support for new instructions to aid floating-point
multiplication and addition of complex numbers. Expose the support
via HWCAP and MRS emulation

Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
arm64: v8.3: Support for Javascript conversion instruction 2017-03-20T16:29:28+00:00 Suzuki K Poulose suzuki.poulose@arm.com 2017-03-14T18:13:25+00:00 c8c3798d2369e4285da44b244638eafe446a8f8a ARMv8.3 adds support for a new instruction to perform conversion from double precision floating point to integer to match the architected behaviour of the equivalent Javascript conversion. Expose the availability via HWCAP and MRS emulation. Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> 
ARMv8.3 adds support for a new instruction to perform conversion
from double precision floating point to integer  to match the
architected behaviour of the equivalent Javascript conversion.
Expose the availability via HWCAP and MRS emulation.

Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
irqchip/gicv3-its: Add workaround for QDF2400 ITS erratum 0065 2017-03-07T14:34:27+00:00 Shanker Donthineni shankerd@codeaurora.org 2017-03-07T14:20:38+00:00 90922a2d03d84de36bf8a9979d62580102f31a92 On Qualcomm Datacenter Technologies QDF2400 SoCs, the ITS hardware implementation uses 16Bytes for Interrupt Translation Entry (ITE), but reports an incorrect value of 8Bytes in GITS_TYPER.ITTE_size. It might cause kernel memory corruption depending on the number of MSI(x) that are configured and the amount of memory that has been allocated for ITEs in its_create_device(). This patch fixes the potential memory corruption by setting the correct ITE size to 16Bytes. Cc: stable@vger.kernel.org Signed-off-by: Shanker Donthineni <shankerd@codeaurora.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> 
On Qualcomm Datacenter Technologies QDF2400 SoCs, the ITS hardware
implementation uses 16Bytes for Interrupt Translation Entry (ITE),
but reports an incorrect value of 8Bytes in GITS_TYPER.ITTE_size.

It might cause kernel memory corruption depending on the number
of MSI(x) that are configured and the amount of memory that has
been allocated for ITEs in its_create_device().

This patch fixes the potential memory corruption by setting the
correct ITE size to 16Bytes.

Cc: stable@vger.kernel.org
Signed-off-by: Shanker Donthineni <shankerd@codeaurora.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
arm64: Work around Falkor erratum 1003 2017-02-10T11:22:12+00:00 Christopher Covington cov@codeaurora.org 2017-02-08T20:08:37+00:00 38fd94b0275c91071157a03cc27676909b23dcde 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> 
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>
arm64: arch_timer: document Hisilicon erratum 161010101 2017-02-09T18:00:47+00:00 Ding Tianhong dingtianhong@huawei.com 2017-02-09T17:00:34+00:00 6e01398fe4505ac4ac963fe0ca44b25e46783fef Now that we have a workaround for Hisilicon erratum 161010101, notes this in the arm64 silicon-errata document. The new config option is too long to fit in the existing kconfig column, so this is widened to accomodate it. At the same time, an existing whitespace error is corrected, and the existing pattern of a line space between vendors is enforced for recent additions. Signed-off-by: Ding Tianhong <dingtianhong@huawei.com> [Mark: split patch, reword commit message, rework table] 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> 
Now that we have a workaround for Hisilicon erratum 161010101, notes
this in the arm64 silicon-errata document.

The new config option is too long to fit in the existing kconfig column,
so this is widened to accomodate it. At the same time, an existing
whitespace error is corrected, and the existing pattern of a line space
between vendors is enforced for recent additions.

Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
[Mark: split patch, reword commit message, rework table]
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>
arm64: Work around Falkor erratum 1009 2017-02-01T15:41:50+00:00 Christopher Covington cov@codeaurora.org 2017-01-31T17:50:19+00:00 d9ff80f83ecbf4cbdf56d32d01c312498e4fb1cd During a TLB invalidate sequence targeting the inner shareable domain, Falkor may prematurely complete the DSB before all loads and stores using the old translation are observed. Instruction fetches are not subject to the conditions of this erratum. If the original code sequence includes multiple TLB invalidate instructions followed by a single DSB, onle one of the TLB instructions needs to be repeated to work around this erratum. While the erratum only applies to cases in which the TLBI specifies the inner-shareable domain (*IS form of TLBI) and the DSB is ISH form or stronger (OSH, SYS), this changes applies the workaround overabundantly-- to local TLBI, DSB NSH sequences as well--for simplicity. Based on work by Shanker Donthineni <shankerd@codeaurora.org> Signed-off-by: Christopher Covington <cov@codeaurora.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> 
During a TLB invalidate sequence targeting the inner shareable domain,
Falkor may prematurely complete the DSB before all loads and stores using
the old translation are observed. Instruction fetches are not subject to
the conditions of this erratum. If the original code sequence includes
multiple TLB invalidate instructions followed by a single DSB, onle one of
the TLB instructions needs to be repeated to work around this erratum.
While the erratum only applies to cases in which the TLBI specifies the
inner-shareable domain (*IS form of TLBI) and the DSB is ISH form or
stronger (OSH, SYS), this changes applies the workaround overabundantly--
to local TLBI, DSB NSH sequences as well--for simplicity.

Based on work by Shanker Donthineni <shankerd@codeaurora.org>

Signed-off-by: Christopher Covington <cov@codeaurora.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>