Samuel Thibault <samuel.thiba...@ens-lyon.org> wrote:
> > This adds SIGSEGV_FAULT_STACKPOINTER for the hurd-amd64 case
> >
> > --- ./lib/sigsegv.c.original 2023-05-05 10:45:54.673751100 +0000
> > +++ ./lib/sigsegv.c 2023-05-05 10:48:47.903577554 +0000
> > @@ -351,6 +351,17 @@
> > "old esp, if trapped from user". */
> > # define SIGSEGV_FAULT_STACKPOINTER scp->sc_uesp
> >
> > +# elif defined __x86_64__
> > +
> > +/* scp points to a 'struct sigcontext' (defined in
> > + glibc/sysdeps/mach/hurd/x86_64/bits/sigcontext.h).
> > + The registers of this struct get pushed on the stack through
> > + gnumach/x86_64/i386/locore.S:trapall. */
> > +/* Both sc_rsp and sc_ursp appear to have the same value.
> > + It appears more reliable to use sc_ursp because it is labelled as
> > + "old rsp, if trapped from user". */
> > +# define SIGSEGV_FAULT_STACKPOINTER scp->sc_ursp
> > +
> > # endif
> >
> > #endif
Thanks Samuel. The definition of SIGSEGV_FAULT_STACKPOINTER seems correct in
this patch, but the comments are not. I am applying this instead.
I'm calling this "tentative" support for Hurd/x86_64, because
- I have no way to test it,
- some of the code paths involved seem to be incorrect so far, see
https://lists.gnu.org/archive/html/bug-hurd/2023-05/msg00207.html
2023-05-12 Bruno Haible <br...@clisp.org>
sigsegv: Add tentative support for Hurd/x86_64.
Reported by Samuel Thibault <samuel.thiba...@ens-lyon.org>.
* lib/sigsegv.c: Update from libsigsegv/src/fault-hurd-i386.h.
diff --git a/lib/sigsegv.c b/lib/sigsegv.c
index 5e943e4d5d..aadba4e060 100644
--- a/lib/sigsegv.c
+++ b/lib/sigsegv.c
@@ -365,12 +365,26 @@ int libsigsegv_version = LIBSIGSEGV_VERSION;
# define SIGSEGV_FAULT_ADDRESS (unsigned long) code
# define SIGSEGV_FAULT_CONTEXT scp
-# if defined __i386__
+# if defined __x86_64__
+/* 64 bit registers */
+
+/* scp points to a 'struct sigcontext' (defined in
+ glibc/sysdeps/mach/hurd/x86_64/bits/sigcontext.h).
+ The registers, at the moment the signal occurred, get pushed on the stack
+ through gnumach/x86_64/locore.S:alltraps and then copied into the struct
+ through glibc/sysdeps/mach/hurd/x86/trampoline.c. */
+/* sc_rsp is unused (not set by gnumach/x86_64/locore.S:alltraps). We need
+ to use sc_ursp. */
+# define SIGSEGV_FAULT_STACKPOINTER scp->sc_ursp
+
+# elif defined __i386__
+/* 32 bit registers */
/* scp points to a 'struct sigcontext' (defined in
glibc/sysdeps/mach/hurd/i386/bits/sigcontext.h).
- The registers of this struct get pushed on the stack through
- gnumach/i386/i386/locore.S:trapall. */
+ The registers, at the moment the signal occurred, get pushed on the stack
+ through gnumach/i386/i386/locore.S:alltraps and then copied into the struct
+ through glibc/sysdeps/mach/hurd/x86/trampoline.c. */
/* Both sc_esp and sc_uesp appear to have the same value.
It appears more reliable to use sc_uesp because it is labelled as
"old esp, if trapped from user". */
