* Linus Torvalds <torva...@linux-foundation.org> wrote:
> On Wed, Mar 25, 2015 at 10:18 AM, Denys Vlasenko <dvlas...@redhat.com> wrote:
> > The $AUDIT_ARCH_X86_64 parameter to syscall_trace_enter_phase1/2
> > is a 32-bit constant, loading it with 32-bit MOV produces 5-byte insn
> > instead of 10-byte one.
>
> Side note: has anybody talked to the assembler people? This would
> seem to be very much something that the assembler could have noticed
> and done on its own. [...]
Maybe GCC already picks a 32-bit opcode in these small-constant cases,
so there was little incentive to optimize on the GAS side, other than
making it correct.
> [...] It's a bit sad that we need to overspecify these things..
Yeah, that's sad.
Yesterday when I have read Denys's patch I double checked that there's
no other similar (easily identifiable ...) movq opcode left in the
64-bit entry code, so we seem to have squashed most of them.
Thanks,
Ingo
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