On Mon, 25 Mar 2019 11:54:32 -0400 (EDT) Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> wrote: > >> +++ b/sysdeps/unix/sysv/linux/s390/bits/rseq.h > [...] > >> + > >> +/* Signature required before each abort handler code. */ > >> +#define RSEQ_SIG 0x53053053 > > > > Why not a s390 specific value here? > > s390 also has the abort handler in a __rseq_failure section: > > #define RSEQ_ASM_DEFINE_ABORT(label, teardown, abort_label) \ > ".pushsection __rseq_failure, \"ax\"\n\t" \ > ".long " __rseq_str(RSEQ_SIG) "\n\t" \ > __rseq_str(label) ":\n\t" \ > teardown \ > "j %l[" __rseq_str(abort_label) "]\n\t" \ > ".popsection\n\t" > > Same question applies as powerpc: since disassemblers will try to decode > that instruction, would it be better to define it as a valid one ? > > [...] A 4-byte sequence starting with 0x53 is decoded as a "diebr" instruction. And please replace that "j %l[...]" with a "jg %l[...]", the branch target range of the "j" instruction is 64K, not enough for the general case. -- blue skies, Martin. "Reality continues to ruin my life." - Calvin.
