strace/linux/sparc/arch_sigreturn.c

static void
arch_sigreturn(struct tcb *tcp)
{
	long fp = sparc_regs.u_regs[U_REG_FP] + sizeof(struct sparc_stackf);
	struct {
		struct pt_regs si_regs;
		int si_mask;
		void *fpu_save;
		long insns[2] ATTRIBUTE_ALIGNED(8);
		unsigned int extramask[NSIG / 8 / sizeof(int) - 1];
	} frame;

	if (umove(tcp, fp, &frame) < 0) {
		tprintf("{mask=%#lx}", fp);
	} else {
		unsigned int mask[NSIG / 8 / sizeof(int)];

		mask[0] = frame.si_mask;
		memcpy(mask + 1, frame.extramask, sizeof(frame.extramask));
		tprintsigmask_addr("{mask=", mask);
		tprints("}");
	}
}