Hello!
I'm the current maintainer for the Debian sh4 port. I maintain several
buildds as well as port packages for the sh4 architecture.
Recently I discovered qemu for building packages in an emulated chroot
environment with qemu-sh4-static. While setting up python, qemu issued
an error message about an unimplemented syscall, 186 which is sigaltstack.
Looking up the sources, I found that linux-user/syscall.c enables
sigaltstack for a limited number of architectures only. In order to fix
the problem with the missing sigaltstack syscall, I added TARGET_SH4
to the list of architectures which seems to work.
The following sample C program tests the functionality of sigaltstack.
Without my patch, the program segfaults on qemu-sh4. With the patch,
it works as expected.
=====================================================================
#include <setjmp.h>
#include <signal.h>
#include <stdlib.h>
#include <stdio.h>
jmp_buf exit_jmp;
void handler(int x)
{
longjmp(exit_jmp, 1);
}
int f(void)
{
return f();
}
int main(void)
{
stack_t sigstack;
sigstack.ss_sp = malloc(1024*1024);
sigstack.ss_size = 1024*1024;
sigstack.ss_flags = 0;
sigaltstack(&sigstack, NULL);
struct sigaction sa;
sa.sa_handler = handler;
sigemptyset(&sa.sa_mask);
sa.sa_flags = SA_ONSTACK;
sigaction(SIGSEGV, &sa, NULL);
if (setjmp(exit_jmp) == 0)
{
return f();
}
puts("recovered");
return 0;
}
=====================================================================
Any idea what else I should test to verify my changes? Otherwise, it
would be great if my patch could be applied to add sigaltstack for
sh4.
Thanks,
Adrian
> [1] https://wiki.debian.org/SH4/sbuildQEMU
--
.''`. John Paul Adrian Glaubitz
: :' : Debian Developer - glaub...@debian.org
`. `' Freie Universitaet Berlin - glaub...@physik.fu-berlin.de
`- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913
