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: d50240a5f6 ("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
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acpi_object_usage.txt
arm-acpi.txt
booting.txt
cpu-feature-registers.txt
legacy_instructions.txt
memory.txt
silicon-errata.txt
tagged-pointers.txt	arm64: documentation: document tagged pointer stack constraints	2017-05-09 17:43:18 +01:00