On Tue, 17 May 2022 18:09:54 +0200 Thomas Huth <thuth@xxxxxxxxxx> wrote: > On 17/05/2022 14.02, Claudio Imbrenda wrote: > > On Mon, 16 May 2022 16:43:32 +0200 > > Janis Schoetterl-Glausch <scgl@xxxxxxxxxxxxx> wrote: > > > >> gcc 12 warns if a memory operand to inline asm points to memory in the > >> first 4k bytes. However, in our case, these operands are fine, either > >> because we actually want to use that memory, or expect and handle the > >> resulting exception. > >> Therefore, silence the warning. > > > > I really dislike this > > I agree the pragmas are ugly. But maybe we should mimic what the kernel > is doing here? > > $ git show 8b202ee218395 > commit 8b202ee218395319aec1ef44f72043e1fbaccdd6 > Author: Sven Schnelle <svens@xxxxxxxxxxxxx> > Date: Mon Apr 25 14:17:42 2022 +0200 > > s390: disable -Warray-bounds > > gcc-12 shows a lot of array bound warnings on s390. This is caused > by the S390_lowcore macro which uses a hardcoded address of 0. > > Wrapping that with absolute_pointer() works, but gcc no longer knows > that a 12 bit displacement is sufficient to access lowcore. So it > emits instructions like 'lghi %r1,0; l %rx,xxx(%r1)' instead of a > single load/store instruction. As s390 stores variables often > read/written in lowcore, this is considered problematic. Therefore > disable -Warray-bounds on s390 for gcc-12 for the time being, until > there is a better solution. > > ... so we should maybe disable it in the Makefile, too, until the > kernel folks found a nicer solution? it's a bit extreme, but if it's good enough for the kernel, it's good enough for us > > Thomas >
