linux

iv/linux

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Kristina Martsenko f0e421b1bf arm64: documentation: document tagged pointer stack constraints

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>

2017-05-09 17:43:18 +01:00

acpi_object_usage.txt

ARM64: ACPI: Update documentation for latest specification version

2016-06-21 16:26:09 +01:00

arm-acpi.txt

ARM64: ACPI: Update documentation for latest specification version

2016-06-21 16:26:09 +01:00

booting.txt

arm64: add the initrd region to the linear mapping explicitly

2016-04-14 16:20:45 +01:00

cpu-feature-registers.txt

arm64: v8.3: Support for weaker release consistency