static int setup_sigframe()

in kernel/signal.c [614:702]

• 61 lines of code
• 12 McCabe index (conditional complexity)

static int setup_sigframe(struct rt_sigframe_user_layout *user,
			  struct pt_regs *regs, sigset_t *set)
{
	int i, err = 0;
	struct rt_sigframe __user *sf = user->sigframe;

	/* set up the stack frame for unwinding */
	__put_user_error(regs->regs[29], &user->next_frame->fp, err);
	__put_user_error(regs->regs[30], &user->next_frame->lr, err);

	for (i = 0; i < 31; i++)
		__put_user_error(regs->regs[i], &sf->uc.uc_mcontext.regs[i],
				 err);
	__put_user_error(regs->sp, &sf->uc.uc_mcontext.sp, err);
	__put_user_error(regs->pc, &sf->uc.uc_mcontext.pc, err);
	__put_user_error(regs->pstate, &sf->uc.uc_mcontext.pstate, err);

	__put_user_error(current->thread.fault_address, &sf->uc.uc_mcontext.fault_address, err);

	err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));

	if (err == 0 && system_supports_fpsimd()) {
		struct fpsimd_context __user *fpsimd_ctx =
			apply_user_offset(user, user->fpsimd_offset);
		err |= preserve_fpsimd_context(fpsimd_ctx);
	}

	/* fault information, if valid */
	if (err == 0 && user->esr_offset) {
		struct esr_context __user *esr_ctx =
			apply_user_offset(user, user->esr_offset);

		__put_user_error(ESR_MAGIC, &esr_ctx->head.magic, err);
		__put_user_error(sizeof(*esr_ctx), &esr_ctx->head.size, err);
		__put_user_error(current->thread.fault_code, &esr_ctx->esr, err);
	}

	/* Scalable Vector Extension state, if present */
	if (system_supports_sve() && err == 0 && user->sve_offset) {
		struct sve_context __user *sve_ctx =
			apply_user_offset(user, user->sve_offset);
		err |= preserve_sve_context(sve_ctx);
	}

	if (err == 0 && user->extra_offset) {
		char __user *sfp = (char __user *)user->sigframe;
		char __user *userp =
			apply_user_offset(user, user->extra_offset);

		struct extra_context __user *extra;
		struct _aarch64_ctx __user *end;
		u64 extra_datap;
		u32 extra_size;

		extra = (struct extra_context __user *)userp;
		userp += EXTRA_CONTEXT_SIZE;

		end = (struct _aarch64_ctx __user *)userp;
		userp += TERMINATOR_SIZE;

		/*
		 * extra_datap is just written to the signal frame.
		 * The value gets cast back to a void __user *
		 * during sigreturn.
		 */
		extra_datap = (__force u64)userp;
		extra_size = sfp + round_up(user->size, 16) - userp;

		__put_user_error(EXTRA_MAGIC, &extra->head.magic, err);
		__put_user_error(EXTRA_CONTEXT_SIZE, &extra->head.size, err);
		__put_user_error(extra_datap, &extra->datap, err);
		__put_user_error(extra_size, &extra->size, err);

		/* Add the terminator */
		__put_user_error(0, &end->magic, err);
		__put_user_error(0, &end->size, err);
	}

	/* set the "end" magic */
	if (err == 0) {
		struct _aarch64_ctx __user *end =
			apply_user_offset(user, user->end_offset);

		__put_user_error(0, &end->magic, err);
		__put_user_error(0, &end->size, err);
	}

	return err;
}