On Fri, Mar 20, 2020 at 04:26:49PM -0700, Sean Christopherson wrote: > On Fri, Mar 20, 2020 at 05:07:00AM +0200, Jarkko Sakkinen wrote: > > On Thu, Mar 19, 2020 at 01:11:45PM -0700, Sean Christopherson wrote: > > > On Thu, Mar 19, 2020 at 01:03:41PM -0700, Xing, Cedric wrote: > > > > On 3/18/2020 6:11 PM, Sean Christopherson wrote: > > > > > #endif > > > > > SYM_FUNC_START(__vdso_sgx_enter_enclave) > > > > > /* Prolog */ > > > > >@@ -82,7 +84,9 @@ SYM_FUNC_START(__vdso_sgx_enter_enclave) > > > > > .cfi_rel_offset %rbp, 0 > > > > > mov %rsp, %rbp > > > > > .cfi_def_cfa_register %rbp > > > > >+ push %rbx > > > > A CFI directive is needed here: > > > > > > > > .cfi_rel_offset %rbx, -8 > > > > > > Darn, I suspected as much, but wasn't 100% positive. Shouldn't have > > > hedged. :-) > > > > > > Is the rule of thumb for adding directives that one is needed any time > > > there is a new saved value of a register, or if the relative address of > > > the last saved value changes? Are CFI directives only used for > > > non-volatile registers? > > > > AFAIK the convention is just that if you push a register you need to > > offset it so that the FDE that is put into .eh_frame by GCC has the > > information from which locations of the stack the register values are > > copied. > > > > BTW, why use GCC-style ".L-mangled" label names instead of having more > > readable ones? > > Readable as in dropping the .L part? E.g. > > enclu_eenter_eresume: > > I assumed we'd want to keep the local labels out of the symbols file, but > maybe getting them in there would be a good thing? Right, that was the legit reason. Nope, lets keep them then. /Jarkko
