On Fri, Oct 22, 2021 at 07:02:43PM +0100, Mark Rutland wrote: > On Thu, Oct 14, 2021 at 09:58:37PM -0500, madvenka@xxxxxxxxxxxxxxxxxxx wrote: > > From: "Madhavan T. Venkataraman" <madvenka@xxxxxxxxxxxxxxxxxxx> > > > > Currently, there are multiple functions in ARM64 code that walk the > > stack using start_backtrace() and unwind_frame() or start_backtrace() > > and walk_stackframe(). They should all be converted to use > > arch_stack_walk(). This makes maintenance easier. > > > > To do that, arch_stack_walk() must always be defined. arch_stack_walk() > > is within #ifdef CONFIG_STACKTRACE. So, select STACKTRACE in > > arch/arm64/Kconfig. > > I'd prefer if we could decouple ARCH_STACKWALK from STACKTRACE, so that > we don't have to expose /proc/*/stack unconditionally, which Peter > Zijlstra has a patch for: > > https://lore.kernel.org/lkml/20211022152104.356586621@xxxxxxxxxxxxx/ > > ... but regardless the rest of the series looks pretty good, so I'll go > review that, and we can figure out how to queue the bits and pieces in > the right order. FWIW, it looks like the direction of travel there is not go and unify the various arch unwinders, but I would like to not depend on STACKTRACE. Regardless, the initial arch_stack_walk() cleanup patches all look good, so I reckon we should try to get those out of the way and queue those for arm64 soon even if we need some more back-and-forth over the later part of the series. With that in mind, I've picked up Peter's patch decoupling ARCH_STACKWALK from STACKTRACE, and rebased the initial patches from this series atop. Since there's some subtltety in a few cases (and this was easy to miss while reviewing), I've expanded the commit messages with additional rationale as to why each transformation is safe. I've pushed that to: https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git/log/?h=arm64/stacktrace/arch-stack-walk There's a dependency on: https://lore.kernel.org/r/20211029162245.39761-1-mark.rutland@xxxxxxx ... which was queued for v5.16-rc1, but got dropped due to a conflict, and I'm expecting it to be re-queued as a fix for v5.16-rc2 shortly after v5.16-rc1 is tagged. Hopefully that means we have a table base by v5.16-rc2. I'll send the preparatory series as I've prepared it shortly after v5.16-rc1 so that people can shout if I've messed something up. Hopefully it's easy enough to use that as a base for the more involved rework later in this series. Thanks, Mark. > Thanks, > Mark. > > > > > Signed-off-by: Madhavan T. Venkataraman <madvenka@xxxxxxxxxxxxxxxxxxx> > > --- > > arch/arm64/Kconfig | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > > index fdcd54d39c1e..bfb0ce60d820 100644 > > --- a/arch/arm64/Kconfig > > +++ b/arch/arm64/Kconfig > > @@ -35,6 +35,7 @@ config ARM64 > > select ARCH_HAS_SET_DIRECT_MAP > > select ARCH_HAS_SET_MEMORY > > select ARCH_STACKWALK > > + select STACKTRACE > > select ARCH_HAS_STRICT_KERNEL_RWX > > select ARCH_HAS_STRICT_MODULE_RWX > > select ARCH_HAS_SYNC_DMA_FOR_DEVICE > > -- > > 2.25.1 > >
