On Mon, May 4, 2020 at 12:23 AM Uros Bizjak <ubizjak@xxxxxxxxx> wrote: > > On Tue, Apr 28, 2020 at 3:48 PM Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: > > > > On 26/04/20 13:52, Uros Bizjak wrote: > > > Improve handle_external_interrupt_irqoff inline assembly in several ways: > > > - use "n" operand constraint instead of "i" and remove > > > unneeded %c operand modifiers and "$" prefixes > > > - use %rsp instead of _ASM_SP, since we are in CONFIG_X86_64 part > > > - use $-16 immediate to align %rsp > > > - remove unneeded use of __ASM_SIZE macro > > > - define "ss" named operand only for X86_64 > > > > > > The patch introduces no functional changes. > > > > I think I agree with all of these, so the patch is okay! Thanks, > > Actually, after some more thinking, neither "i", and neither "n" is > correct for x86_64 as far as push is concerned. The correct constraint > is "e", but in case the value doesn't fit this constraint, we have to > allow "r" and eventually "m". Let's use "rme", which allows everything > the insn is able to handle, and leave to the compiler to use the > optimal one. GCC uses this constraint internally, and it also fits > 32bit targets. And yes... I forgot that "m" allows stack slots, which won't fly due to clobbered stack pointer. > V3 patch is in the works. V4, actually. Sorry for the mess. Uros.
