[PATCH v2] On ppc64le we HAVE_RELIABLE_STACKTRACE
segher at kernel.crashing.org
Tue Mar 6 04:09:01 AEDT 2018
On Mon, Mar 05, 2018 at 05:49:28PM +0100, Torsten Duwe wrote:
> The "Power Architecture 64-Bit ELF V2 ABI" says in section 22.214.171.124:
> [...] 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.
> – In instances where a function’s 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
> – The function shall save the link register that contains its return
> address in the LR save doubleword of its caller’s stack frame before
> calling another function.
All of this is also true for the other PowerPC ABIs, fwiw (both 32-bit
and 64-bit; the offset of the LR save slot isn't the same in all ABIs).
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