[IA64] align signal-frame even when not using alternate signal-stack
At the moment, attempting to invoke a signal-handler on the normal
stack is guaranteed to fail if the stack-pointer happens not to be
16-byte aligned. This is because the signal-trampoline will attempt
to store fp-regs with stf.spill instructions, which will trap for
misaligned addresses. This isn't terribly useful behavior. It's
better to just always align the signal frame to the next lower 16-byte
boundary.
Signed-off-by: David Mosberger-Tang <David.Mosberger@acm.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
diff --git a/arch/ia64/kernel/signal.c b/arch/ia64/kernel/signal.c
index 774f34b..58ce07e 100644
--- a/arch/ia64/kernel/signal.c
+++ b/arch/ia64/kernel/signal.c
@@ -387,15 +387,14 @@
struct sigscratch *scr)
{
extern char __kernel_sigtramp[];
- unsigned long tramp_addr, new_rbs = 0;
+ unsigned long tramp_addr, new_rbs = 0, new_sp;
struct sigframe __user *frame;
long err;
- frame = (void __user *) scr->pt.r12;
+ new_sp = scr->pt.r12;
tramp_addr = (unsigned long) __kernel_sigtramp;
- if ((ka->sa.sa_flags & SA_ONSTACK) && sas_ss_flags((unsigned long) frame) == 0) {
- frame = (void __user *) ((current->sas_ss_sp + current->sas_ss_size)
- & ~(STACK_ALIGN - 1));
+ if ((ka->sa.sa_flags & SA_ONSTACK) && sas_ss_flags(new_sp) == 0) {
+ new_sp = current->sas_ss_sp + current->sas_ss_size;
/*
* We need to check for the register stack being on the signal stack
* separately, because it's switched separately (memory stack is switched
@@ -404,7 +403,7 @@
if (!rbs_on_sig_stack(scr->pt.ar_bspstore))
new_rbs = (current->sas_ss_sp + sizeof(long) - 1) & ~(sizeof(long) - 1);
}
- frame = (void __user *) frame - ((sizeof(*frame) + STACK_ALIGN - 1) & ~(STACK_ALIGN - 1));
+ frame = (void __user *) ((new_sp - sizeof(*frame)) & -STACK_ALIGN);
if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
return force_sigsegv_info(sig, frame);