On Fri, 2018-05-04 at 12:38:34 UTC, Torsten Duwe wrote: > The "Power Architecture 64-Bit ELF V2 ABI" says in section 2.3.2.3: > > [...] There are several rules that must be adhered to in order to ensure > reliable and consistent call chain backtracing: > > * Before a function calls any other function, it shall establish its > own stack frame, whose size shall be a multiple of 16 bytes. > > â In instances where a functionâs prologue creates a stack frame, the > back-chain word of the stack frame shall be updated atomically with > the value of the stack pointer (r1) when a back chain is implemented. > (This must be supported as default by all ELF V2 ABI-compliant > environments.) > [...] > â The function shall save the link register that contains its return > address in the LR save doubleword of its callerâs stack frame before > calling another function. > > To me this sounds like the equivalent of HAVE_RELIABLE_STACKTRACE. > This patch may be unneccessarily limited to ppc64le, but OTOH the only > user of this flag so far is livepatching, which is only implemented on > PPCs with 64-LE, a.k.a. ELF ABI v2. > > Feel free to add other ppc variants, but so far only ppc64le got tested. > > This change also implements save_stack_trace_tsk_reliable() for ppc64le > that checks for the above conditions, where possible. > > Signed-off-by: Torsten Duwe <d...@suse.de> > Signed-off-by: Nicolai Stange <nsta...@suse.de> > Acked-by: Josh Poimboeuf <jpoim...@redhat.com>
Applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/df78d3f6148092d33a9a24c7a9cfac cheers
