To enable RELIABLE_STACKTRACE and LIVEPATCH on arm64, we need to substantially rework arm64's unwinding code. As part of this, we want to minimize the set of unwind interfaces we expose, and avoid open-coding of unwind logic outside of stacktrace.c. Currently return_address() walks the stack of the current task by calling start_backtrace() with return_address as the PC and the frame pointer of return_address() as the next frame, iterating unwind steps using walk_stackframe(). This is functionally equivalent to calling arch_stack_walk() for the current stack, which will start from its caller (i.e. return_address()) as the PC and it's caller's frame record as the next frame. Make return_address() use arch_stackwalk(). This simplifies return_address(), and in future will alow us to make walk_stackframe() private to stacktrace.c. There should be no functional change as a result of this patch. Signed-off-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com> Tested-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Mark Brown <broonie@kernel.org> Reviewed-by: Mark Rutland <mark.rutland@arm.com> [Mark: elaborate commit message, fix includes] Signed-off-by: Mark Rutland <mark.rutland@arm.com> Link: https://lore.kernel.org/r/20211129142849.3056714-7-mark.rutland@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.
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