From: Andrew Cooper Date: Tue, 13 Aug 2019 11:53:15 +0000 (+0100) Subject: x86/tss: Fix clang build following c/s 7888440625 X-Git-Tag: archive/raspbian/4.14.0+80-gd101b417b7-1+rpi1^2~63^2~1743 X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=1722da6c0c6f6b7b320bdd239c46c0cb1048f804;p=xen.git x86/tss: Fix clang build following c/s 7888440625 Clang-3.5 from Debian Jessie fails with: smpboot.c:829:29: error: statement expression not allowed at file scope BUILD_BUG_ON(sizeof(this_cpu(tss_page)) != PAGE_SIZE); ^ /local/xen.git/xen/include/asm/percpu.h:14:7: note: expanded from macro 'this_cpu' (*RELOC_HIDE(&per_cpu__##var, get_cpu_info()->per_cpu_offset)) ^ /local/xen.git/xen/include/xen/compiler.h:98:3: note: expanded from macro 'RELOC_HIDE' ({ unsigned long __ptr; \ ^ /local/xen.git/xen/include/xen/lib.h:26:53: note: expanded from macro 'BUILD_BUG_ON' #define BUILD_BUG_ON(cond) ((void)BUILD_BUG_ON_ZERO(cond)) ^ /local/xen.git/xen/include/xen/lib.h:25:57: note: expanded from macro 'BUILD_BUG_ON_ZERO' #define BUILD_BUG_ON_ZERO(cond) sizeof(struct { int:-!!(cond); }) ^ 1 error generated. /local/xen.git/xen/Rules.mk:202: recipe for target 'smpboot.o' failed This is obviously a compiler bug because the BUILD_BUG_ON() is not at file scope. However, it can be worked around by using a local variable. Spotted by Gitlab CI. Signed-off-by: Andrew Cooper Reviewed-by: Wei Liu --- diff --git a/xen/arch/x86/smpboot.c b/xen/arch/x86/smpboot.c index 5057109a77..5c4254ac87 100644 --- a/xen/arch/x86/smpboot.c +++ b/xen/arch/x86/smpboot.c @@ -826,9 +826,11 @@ static int setup_cpu_root_pgt(unsigned int cpu) rc = clone_mapping(idt_tables[cpu], rpt); if ( !rc ) { - BUILD_BUG_ON(sizeof(this_cpu(tss_page)) != PAGE_SIZE); + struct tss_page *ptr = &per_cpu(tss_page, cpu); - rc = clone_mapping(&per_cpu(tss_page, cpu).tss, rpt); + BUILD_BUG_ON(sizeof(*ptr) != PAGE_SIZE); + + rc = clone_mapping(&ptr->tss, rpt); } if ( !rc ) rc = clone_mapping((void *)per_cpu(stubs.addr, cpu), rpt);