On Mon, Jul 23, 2018 at 07:11:50PM +0100, Mark Brown wrote: > On Mon, Jul 23, 2018 at 05:59:12PM +0100, Build bot for Mark Brown wrote: > > Today's -next fails to build an arm64 allmodconfig with: > > > arm64-allmodconfig > > ERROR: "__sync_icache_dcache" [drivers/xen/xen-privcmd.ko] undefined! > > using > > aarch64-linux-gnu-gcc (Linaro GCC 5.3-2016.05) 5.3.1 20160412 > > however it builds perfectly fine with > > aarch64-linux-gnu-gcc (Linaro GCC 6.2-2016.11) 6.2.1 20161016 > > which honestly seems like a sensible and worthwhile upgrade at this > point anyway given that it's a year and a half old so I'm going to do > that for my builder (perhaps even jump on a newer version) but it seemed > worth highlighting in case this is considered undesirable. A similar > issue is hitting on KernelCI, we should probably look at upgrading the > toolchain there too. Hmm, it looks to me like this comes about because xen/privcmd.c is being built as a module, but contains a call to set_pte_at() with a special pte: pte_t pte = pte_mkspecial(pfn_pte(page_to_pfn(page), r->prot)); set_pte_at(r->mm, addr, ptep, pte); which on arm64 contains: if (pte_present(pte) && pte_user_exec(pte) && !pte_special(pte)) __sync_icache_dcache(pte); so GCC 6 can optimise away the call to the non-exported symbol, but GCC 5 has trouble. What I don't understand is why this suddenly cropped up. Did GCC 5 build linux-next arm64 allmodconfig last week? Cheers, Will -- To unsubscribe from this list: send the line "unsubscribe linux-next" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
