On Fri, Apr 17, 2020 at 2:07 PM Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: > > On 17/04/20 13:35, Uros Bizjak wrote: > > Improve handle_external_interrupt_irqoff inline assembly in several ways: > > - use __stringify to use __KERNEL_DS and __KERNEL_CS directly in assembler > > What's the advantage of this to pushing cs and ss? We are faking an > interrupt gate, and interrupts push cs and ss not __KERNEL_DS and > __KERNEL_CS. I see. If the current form is documenting the above, then there is indeed no compelling reason for the change. > > > - use %rsp instead of _ASM_SP, since we are in CONFIG_X86_64 part > > - use $-16 immediate to align %rsp > > - avoid earlyclobber by using "l" GCC input operand constraint > > What is this and where is it documented?!? :) I was going to say that it is documented in [1] under x86 family section, but indeed, there is no description of "l" constraint. It is internal to the compiler. :( (define_register_constraint "l" "INDEX_REGS" "@internal Any register that can be used as the index in a base+index memory access: that is, any general register except the stack pointer.") Other changes are minor and really not worth the maintainer's time to handle the patch. Please consider the patch retracted. [1] https://gcc.gnu.org/onlinedocs/gcc/Machine-Constraints.html Uros.
