>>> On 29.01.18 at 13:26, <roger....@citrix.com> wrote: > Clang assembler doesn't support using .skip with non-absolute > expressions: > > entry.S:109:15: error: expected absolute expression > .skip .Lcr4_alt_end - .Lcr4_alt, 0x90 > ^ > > This usage of .skip was to fill code sections with NOPs in order for > them to be patched at run time if required by the alternatives > framework. Instead of using .skip use the appropriate number of NOPs > to match the size of the alternative code.
NAK - I've voiced a number of times my opposition to Andrew adding the various ASM_NOP<N> in his Spectre v2 series, and I'm planning to eliminate them in due course (by using - you guess it - .skip). It is pretty much unacceptable to me to have to encode the size of certain instructions in a second place, risking them to go out of sync with what they shadow. If ugliness like this is needed to support clang's integrated assembler, then I see no way other than avoiding its use. Jan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
