Re: [PATCH v1] powerpc: Include running function as first entry in save_stack_trace() and friends

Hi! On Wed, Mar 10, 2021 at 11:32:20AM +, Mark Rutland wrote: > On Tue, Mar 09, 2021 at 04:05:32PM -0600, Segher Boessenkool wrote: > > On Tue, Mar 09, 2021 at 04:05:23PM +, Mark Rutland wrote: > > > On Thu, Mar 04, 2021 at 03:54:48PM -0600, Segher Boessenkool wrote: > > > > On Thu, Mar

Re: [PATCH v1] powerpc: Include running function as first entry in save_stack_trace() and friends

On Tue, Mar 09, 2021 at 04:05:32PM -0600, Segher Boessenkool wrote: > Hi! > > On Tue, Mar 09, 2021 at 04:05:23PM +, Mark Rutland wrote: > > On Thu, Mar 04, 2021 at 03:54:48PM -0600, Segher Boessenkool wrote: > > > On Thu, Mar 04, 2021 at 02:57:30PM +, Mark Rutland wrote: > > > > It looks

Re: [PATCH v1] powerpc: Include running function as first entry in save_stack_trace() and friends

Hi! On Tue, Mar 09, 2021 at 04:05:23PM +, Mark Rutland wrote: > On Thu, Mar 04, 2021 at 03:54:48PM -0600, Segher Boessenkool wrote: > > On Thu, Mar 04, 2021 at 02:57:30PM +, Mark Rutland wrote: > > > It looks like GCC is happy to give us the function-entry-time FP if we use > > >

Re: [PATCH v1] powerpc: Include running function as first entry in save_stack_trace() and friends

On Thu, Mar 04, 2021 at 03:54:48PM -0600, Segher Boessenkool wrote: > Hi! Hi Segher, > On Thu, Mar 04, 2021 at 02:57:30PM +, Mark Rutland wrote: > > It looks like GCC is happy to give us the function-entry-time FP if we use > > __builtin_frame_address(1), > > From the GCC manual: >

Re: [PATCH v1] powerpc: Include running function as first entry in save_stack_trace() and friends

On Fri, Mar 05, 2021 at 07:38:25AM +0100, Christophe Leroy wrote: > Le 04/03/2021 à 20:24, Segher Boessenkool a écrit : > https://github.com/linuxppc/linux/commit/a9a3ed1eff36 > > > > >That is much heavier than needed (an mb()). You can just put an empty > >inline asm after a call before a

Re: [PATCH v1] powerpc: Include running function as first entry in save_stack_trace() and friends

On Thu, Mar 04, 2021 at 08:01:29PM +0100, Marco Elver wrote: > On Thu, 4 Mar 2021 at 19:51, Mark Rutland wrote: > > On Thu, Mar 04, 2021 at 07:22:53PM +0100, Marco Elver wrote: > > > I was having this problem with KCSAN, where the compiler would > > > tail-call-optimize __tsan_X instrumentation.

Re: [PATCH v1] powerpc: Include running function as first entry in save_stack_trace() and friends

Le 04/03/2021 à 20:24, Segher Boessenkool a écrit : On Thu, Mar 04, 2021 at 09:54:44AM -0800, Nick Desaulniers wrote: On Thu, Mar 4, 2021 at 9:42 AM Marco Elver wrote: include/linux/compiler.h:246: prevent_tail_call_optimization commit a9a3ed1eff36 ("x86: Fix early boot crash on gcc-10,

Re: [PATCH v1] powerpc: Include running function as first entry in save_stack_trace() and friends

Hi! On Thu, Mar 04, 2021 at 02:57:30PM +, Mark Rutland wrote: > It looks like GCC is happy to give us the function-entry-time FP if we use > __builtin_frame_address(1), >From the GCC manual: Calling this function with a nonzero argument can have unpredictable effects, including

Re: [PATCH v1] powerpc: Include running function as first entry in save_stack_trace() and friends

On Thu, Mar 04, 2021 at 09:54:44AM -0800, Nick Desaulniers wrote: > On Thu, Mar 4, 2021 at 9:42 AM Marco Elver wrote: > include/linux/compiler.h:246: > prevent_tail_call_optimization > > commit a9a3ed1eff36 ("x86: Fix early boot crash on gcc-10, third try") That is much heavier than needed (an

Re: [PATCH v1] powerpc: Include running function as first entry in save_stack_trace() and friends

On Thu, 4 Mar 2021 at 19:51, Mark Rutland wrote: > On Thu, Mar 04, 2021 at 07:22:53PM +0100, Marco Elver wrote: > > On Thu, 4 Mar 2021 at 19:02, Mark Rutland wrote: > > > On Thu, Mar 04, 2021 at 06:25:33PM +0100, Marco Elver wrote: > > > > On Thu, Mar 04, 2021 at 04:59PM +, Mark Rutland

Re: [PATCH v1] powerpc: Include running function as first entry in save_stack_trace() and friends

On Thu, Mar 04, 2021 at 07:22:53PM +0100, Marco Elver wrote: > On Thu, 4 Mar 2021 at 19:02, Mark Rutland wrote: > > On Thu, Mar 04, 2021 at 06:25:33PM +0100, Marco Elver wrote: > > > On Thu, Mar 04, 2021 at 04:59PM +, Mark Rutland wrote: > > > > On Thu, Mar 04, 2021 at 04:30:34PM +0100, Marco

Re: [PATCH v1] powerpc: Include running function as first entry in save_stack_trace() and friends

On Thu, 4 Mar 2021 at 19:02, Mark Rutland wrote: > On Thu, Mar 04, 2021 at 06:25:33PM +0100, Marco Elver wrote: > > On Thu, Mar 04, 2021 at 04:59PM +, Mark Rutland wrote: > > > On Thu, Mar 04, 2021 at 04:30:34PM +0100, Marco Elver wrote: > > > > On Thu, 4 Mar 2021 at 15:57, Mark Rutland

Re: [PATCH v1] powerpc: Include running function as first entry in save_stack_trace() and friends

On Thu, Mar 04, 2021 at 06:25:33PM +0100, Marco Elver wrote: > On Thu, Mar 04, 2021 at 04:59PM +, Mark Rutland wrote: > > On Thu, Mar 04, 2021 at 04:30:34PM +0100, Marco Elver wrote: > > > On Thu, 4 Mar 2021 at 15:57, Mark Rutland wrote: > > > > [adding Mark Brown] > > > > > > > > The bigger

Re: [PATCH v1] powerpc: Include running function as first entry in save_stack_trace() and friends

On Thu, Mar 4, 2021 at 9:42 AM Marco Elver wrote: > > On Thu, Mar 04, 2021 at 04:59PM +, Mark Rutland wrote: > > On Thu, Mar 04, 2021 at 04:30:34PM +0100, Marco Elver wrote: > > > On Thu, 4 Mar 2021 at 15:57, Mark Rutland wrote: > > > > [adding Mark Brown] > > > > > > > > The bigger problem

Re: [PATCH v1] powerpc: Include running function as first entry in save_stack_trace() and friends

On Thu, Mar 04, 2021 at 04:59PM +, Mark Rutland wrote: > On Thu, Mar 04, 2021 at 04:30:34PM +0100, Marco Elver wrote: > > On Thu, 4 Mar 2021 at 15:57, Mark Rutland wrote: > > > [adding Mark Brown] > > > > > > The bigger problem here is that skipping is dodgy to begin with, and > > > this is

Re: [PATCH v1] powerpc: Include running function as first entry in save_stack_trace() and friends

On Thu, Mar 04, 2021 at 04:30:34PM +0100, Marco Elver wrote: > On Thu, 4 Mar 2021 at 15:57, Mark Rutland wrote: > > [adding Mark Brown] > > > > The bigger problem here is that skipping is dodgy to begin with, and > > this is still liable to break in some cases. One big concern is that > >

Re: [PATCH v1] powerpc: Include running function as first entry in save_stack_trace() and friends

On Thu, 4 Mar 2021 at 15:57, Mark Rutland wrote: > [adding Mark Brown] > > On Wed, Mar 03, 2021 at 04:20:43PM +0100, Marco Elver wrote: > > On Wed, Mar 03, 2021 at 03:52PM +0100, Christophe Leroy wrote: > > > Le 03/03/2021 � 15:38, Marco Elver a �crit�: > > > > On Wed, 3 Mar 2021 at 15:09,

Re: [PATCH v1] powerpc: Include running function as first entry in save_stack_trace() and friends

[adding Mark Brown] On Wed, Mar 03, 2021 at 04:20:43PM +0100, Marco Elver wrote: > On Wed, Mar 03, 2021 at 03:52PM +0100, Christophe Leroy wrote: > > Le 03/03/2021 � 15:38, Marco Elver a �crit�: > > > On Wed, 3 Mar 2021 at 15:09, Christophe Leroy > > > wrote: > > > > > > > > It seems like

Re: [PATCH v1] powerpc: Include running function as first entry in save_stack_trace() and friends

On Wed, Mar 03, 2021 at 03:52PM +0100, Christophe Leroy wrote: > Le 03/03/2021 à 15:38, Marco Elver a écrit : > > On Wed, 3 Mar 2021 at 15:09, Christophe Leroy > > wrote: > > > > > > It seems like all other sane architectures, namely x86 and arm64 > > > at least, include the running function as

Re: [PATCH v1] powerpc: Include running function as first entry in save_stack_trace() and friends

Le 03/03/2021 à 15:38, Marco Elver a écrit : On Wed, 3 Mar 2021 at 15:09, Christophe Leroy wrote: It seems like all other sane architectures, namely x86 and arm64 at least, include the running function as top entry when saving stack trace. Functionnalities like KFENCE expect it. Do the

Re: [PATCH v1] powerpc: Include running function as first entry in save_stack_trace() and friends

On Wed, 3 Mar 2021 at 15:09, Christophe Leroy wrote: > > It seems like all other sane architectures, namely x86 and arm64 > at least, include the running function as top entry when saving > stack trace. > > Functionnalities like KFENCE expect it. > > Do the same on powerpc, it allows KFENCE to