Messages in this thread | | | Date | Sat, 22 Jan 2005 20:03:07 +1100 | From | Paul Mackerras <> | Subject | Re: [PATCH] PPC: fix stack alignment for signal handlers |
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Roland McGrath writes:
> For PPC32 signal handlers, while the frame itself was of properly aligned > size, no alignment of the starting stack pointer was done at all, so that a > signal handler can still get a misaligned stack pointer if the interrupted > registers had one, though the kernel isn't gratuitously misaligning good > ones like it is for PPC64. I added explicit alignment to fix that.
This part is unnecessary, because arch/ppc/kernel/signal.c:do_signal() already aligns the stack pointer to a 16-byte boundary:
if ((ka.sa.sa_flags & SA_ONSTACK) && current->sas_ss_size && !on_sig_stack(regs->gpr[1])) newsp = current->sas_ss_sp + current->sas_ss_size; else newsp = regs->gpr[1]; newsp &= ~0xfUL;
/* Whee! Actually deliver the signal. */ if (ka.sa.sa_flags & SA_SIGINFO) handle_rt_signal(signr, &ka, &info, oldset, regs, newsp); else handle_signal(signr, &ka, &info, oldset, regs, newsp);
The additions to arch/ppc64/kernel/signal32.c are likewise unnecessary, because do_signal32() also does newsp &= ~0xfUL (in fact the code there is very similar to the ppc32 code).
You are correct about the 64-bit case though. I thought we had fixed that but evidently not. Your patch looks fine as far as arch/ppc64/kernel/signal.c is concerned.
Regards, Paul. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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