What would be the benefit of using .uc_regs instead of .regs? The current code works entirely fine as it, it just needs an include of the Linux Kernel header defining the pt_regs type (which my proposed patch adds).
Furthermore, it seems to me that .uc_regs is only available on powerpc but not on power64 [1]? musl libc also only defines the .uc_regs member for powerpc [2] and not for powerpc64 [3] on ucontext_t. Is there any documentation for .uc_regs on PowerPC? Sincerely, Sören [1]: https://github.com/torvalds/linux/blob/c3617f72036c909e1f6086b5b9e364e0ef90a6da/arch/powerpc/include/uapi/asm/ucontext.h#L24-L27 [2]: https://git.musl-libc.org/cgit/musl/tree/arch/powerpc/bits/signal.h?id=f8bdc3048216f41eaaf655524fa286cfb1184a70#n67 [3]: https://git.musl-libc.org/cgit/musl/tree/arch/powerpc64/bits/signal.h?id=f8bdc3048216f41eaaf655524fa286cfb1184a70#n56 Ian Lance Taylor <i...@golang.org> wrote: > Note for gofrontend-dev: on gcc-patches only Andreas Schwab suggested > using uc_regs instead of regs, which does look correct to me. > > Ian > > On Mon, Feb 21, 2022 at 8:47 AM Sören Tempel <soe...@soeren-tempel.net> wrote: > > > > Ping. > > > > Summary: Fix build of libgo on PPC with musl libc and libucontext by > > explicitly including the Linux header defining `struct pt_regs` instead of > > relying on other libc headers to include it implicitly. > > > > See: https://gcc.gnu.org/pipermail/gcc-patches/2022-January/587520.html > > > > If the patch needs to be revised further please let me know. This patch has > > been applied at Alpine Linux downstream (which uses musl libc) for a while, > > I > > have not tested it on other systems. > > > > Greetings, > > Sören > > > > Sören Tempel <soe...@soeren-tempel.net> wrote: > > > Both glibc and musl libc declare pt_regs as an incomplete type. This > > > type has to be completed by inclusion of another header. On Linux, the > > > asm/ptrace.h header file provides this type definition. Without > > > including this header file, it is not possible to access the regs member > > > of the mcontext_t struct as done in libgo/runtime/go-signal.c. On glibc, > > > other headers (e.g. sys/user.h) include asm/ptrace.h but on musl > > > asm/ptrace.h is not included by other headers and thus the > > > aforementioned files do not compile without an explicit include of > > > asm/ptrace.h: > > > > > > libgo/runtime/go-signal.c: In function 'getSiginfo': > > > libgo/runtime/go-signal.c:227:63: error: invalid use of undefined > > > type 'struct pt_regs' > > > 227 | ret.sigpc = > > > ((ucontext_t*)(context))->uc_mcontext.regs->nip; > > > | > > > > > > See also: > > > > > > * > > > https://git.musl-libc.org/cgit/musl/commit/?id=c2518a8efb6507f1b41c3b12e03b06f8f2317a1f > > > * https://github.com/kaniini/libucontext/issues/36 > > > > > > Signed-off-by: Sören Tempel <soe...@soeren-tempel.net> > > > > > > ChangeLog: > > > > > > * libgo/runtime/go-signal.c: Include asm/ptrace.h for the > > > definition of pt_regs (used by mcontext_t) on PowerPC. > > > --- > > > libgo/runtime/go-signal.c | 6 ++++++ > > > 1 file changed, 6 insertions(+) > > > > > > diff --git a/libgo/runtime/go-signal.c b/libgo/runtime/go-signal.c > > > index d30d1603adc..fc01e04e4a1 100644 > > > --- a/libgo/runtime/go-signal.c > > > +++ b/libgo/runtime/go-signal.c > > > @@ -10,6 +10,12 @@ > > > #include <sys/time.h> > > > #include <ucontext.h> > > > > > > +// On PowerPC, ucontext.h uses a pt_regs struct as an incomplete > > > +// type. This type must be completed by including asm/ptrace.h. > > > +#ifdef __PPC__ > > > +#include <asm/ptrace.h> > > > +#endif > > > + > > > #include "runtime.h" > > > > > > #ifndef SA_RESTART > > > > -- > > You received this message because you are subscribed to the Google Groups > > "gofrontend-dev" group. > > To unsubscribe from this group and stop receiving emails from it, send an > > email to gofrontend-dev+unsubscr...@googlegroups.com. > > To view this discussion on the web visit > > https://groups.google.com/d/msgid/gofrontend-dev/2FICMX0ORZ6O1.3DYXRTDHNGXCN%408pit.net.
