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[PATCH] uml: Move signal handlers to arch code

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Have most signals go through an arch-provided handler which recovers the
sigcontext and then calls a generic handler.  This replaces the
ARCH_GET_SIGCONTEXT macro, which was somewhat fragile.  On x86_64, recovering
%rdx (which holds the sigcontext pointer) must be the first thing that
happens.  sig_handler duly invokes that first, but there is no guarantee that
I can see that instructions won't be reordered such that %rdx is used before
that.  Having the arch provide the handler seems much more robust.

Some signals in some parts of UML require their own handlers - these places
don't call set_handler any more.  They call sigaction or signal themselves.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Jeff Dike
2006-09-25 23:33:04 -07:00
committed by Linus Torvalds
parent 19bdf0409f
commit 4b84c69b5f
12 changed files with 102 additions and 89 deletions
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17
arch/um/os-Linux/skas/process.c
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@@ -189,14 +189,25 @@ static int userspace_tramp(void *stack)
}
}
if(!ptrace_faultinfo && (stack != NULL)){
struct sigaction sa;
unsigned long v = UML_CONFIG_STUB_CODE +
(unsigned long) stub_segv_handler -
(unsigned long) &__syscall_stub_start;
set_sigstack((void *) UML_CONFIG_STUB_DATA, page_size());
set_handler(SIGSEGV, (void *) v, SA_ONSTACK,
SIGIO, SIGWINCH, SIGALRM, SIGVTALRM,
SIGUSR1, -1);
sigemptyset(&sa.sa_mask);
sigaddset(&sa.sa_mask, SIGIO);
sigaddset(&sa.sa_mask, SIGWINCH);
sigaddset(&sa.sa_mask, SIGALRM);
sigaddset(&sa.sa_mask, SIGVTALRM);
sigaddset(&sa.sa_mask, SIGUSR1);
sa.sa_flags = SA_ONSTACK;
sa.sa_handler = (void *) v;
sa.sa_restorer = NULL;
if(sigaction(SIGSEGV, &sa, NULL) < 0)
panic("userspace_tramp - setting SIGSEGV handler "
"failed - errno = %d\n", errno);
}
os_stop_process(os_getpid());