linux-user/ppc: restore fp_status from FPSCR on sigreturn

restore_user_regs() restores the PPC FPSCR with a direct assignment: env->fpscr = (uint32_t) fpscr; ppc_store_fpscr() exists precisely to write FPSCR and keep the derived env->fp_status in sync: it calls fpscr_set_rounding_mode() to update the softfloat rounding mode, and set_float_rebias_overflow/underflow() to reflect the FP_OE/FP_UE enable bits. The direct assignment bypasses all of this. On sigreturn, interrupted code resumes with whatever rounding mode and overflow/underflow-rebias state the signal handler last installed in fp_status, rather than the state that was saved at signal delivery. Replace the direct assign with ppc_store_fpscr(). The FPSCR_MTFS_MASK applied inside ppc_store_fpscr() only excludes the computed FP_FEX and FP_VX bits, which it re-derives correctly from the exception and enable bits in the restored value. Fixes: bcd4933a23 ("linux-user: ppc signal handling") Cc: qemu-stable@nongnu.org Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Matt Turner <mattst88@gmail.com> Signed-off-by: Helge Deller <deller@gmx.de>