Hi Arnd,
On Mon, 2 Feb 2026 at 11:53, Geert Uytterhoeven <[email protected]> wrote:
> On Wed, 7 Jan 2026 at 09:20, Arnd Bergmann <[email protected]> wrote:
> > On Tue, Jan 6, 2026, at 20:31, Geert Uytterhoeven wrote:
> > > On Tue, 6 Jan 2026 at 16:38, Arnd Bergmann <[email protected]> wrote:
> > >> On Tue, Jan 6, 2026, at 14:40, John Paul Adrian Glaubitz wrote:
> > >> > On Tue, 2026-01-06 at 14:34 +0100, Kolbjørn Barmen wrote:
> > >> The diffstat is
> > >>
> > >> 407 files changed, 2433 insertions(+), 754 deletions(-)
> > >>
> > >> and I think this touches around 1500 structures, though
> > >> most files only have a single one.
> > >
> > > Thanks, this seems to work fine for atari_defconfig, and generates
> > > the exact same code as before.
I kept on updating this during the last few months (I guess/hope you
did the same?)
> >
> > Ok, good. The more interesting bit then is what happens when
> > you actually turn on -malign-int for the kernel itself. There
>
> It fails to build due to wrong and missing annotations in union __sifields:
>
> arch/m68k/kernel/signal.c:621:9: note: in expansion of macro ‘BUILD_BUG_ON’
> 621 | BUILD_BUG_ON(offsetof(siginfo_t, si_lower) != 0x12);
>
> which is probably the same issue Kolla was seeing.
The following are failing with -malign-int:
BUILD_BUG_ON(offsetof(siginfo_t, si_lower) != 0x12);
BUILD_BUG_ON(offsetof(siginfo_t, si_upper) != 0x16);
BUILD_BUG_ON(offsetof(siginfo_t, si_pkey) != 0x12);
All of these are due to
#define __ADDR_BND_PKEY_PAD (__alignof__(void *) < sizeof(short) ? \
sizeof(short) : __alignof__(void *))
(which is no longer correct for m68k and -malign-int), and incorrect/missing
annotations for the three fields succeeding the use of the former.
I couldn't fix it using the __uapi_* infrastructure you provided, but
the following (gmail-whitespace-damaged) patch fixes the BUILD_BUG_ON()s:
--- a/include/uapi/asm-generic/siginfo.h
+++ b/include/uapi/asm-generic/siginfo.h
@@ -71,8 +71,12 @@ union __sifields {
struct {
void __user *_addr; /* faulting insn/memory ref. */
+#ifdef __m68k__
+#define __ADDR_BND_PKEY_PAD sizeof(short)
+#else
#define __ADDR_BND_PKEY_PAD (__alignof__(void *) < sizeof(short) ? \
sizeof(short) : __alignof__(void *))
+#endif
union {
/* used on alpha and sparc */
int _trapno; /* TRAP # which caused the signal */
@@ -84,13 +88,13 @@ union __sifields {
/* used when si_code=SEGV_BNDERR */
struct {
char _dummy_bnd[__ADDR_BND_PKEY_PAD];
- void __user *_lower;
- void __user *_upper;
+ void __user *_lower __attribute__
((packed, aligned(2)));
+ void __user *_upper __attribute__
((packed, aligned(2)));
} _addr_bnd;
/* used when si_code=SEGV_PKUERR */
struct {
char _dummy_pkey[__ADDR_BND_PKEY_PAD];
- __u32 _pkey;
+ __u32 _pkey __attribute__ ((packed,
aligned(2)));
} _addr_pkey;
/* used when si_code=TRAP_PERF */
struct {
Unfortunately the resulting kernel hangs (on ARAnyM) after:
Console: colour dummy device 80x25
printk: legacy console [tty0] enabled
Back to real work...
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
