From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52293) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aorJX-0007Bi-Ov for qemu-devel@nongnu.org; Sat, 09 Apr 2016 07:44:32 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aorJU-0008F2-Iq for qemu-devel@nongnu.org; Sat, 09 Apr 2016 07:44:31 -0400 Received: from chuckie.co.uk ([82.165.15.123]:37576 helo=s16892447.onlinehome-server.info) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aorJU-0008EE-CV for qemu-devel@nongnu.org; Sat, 09 Apr 2016 07:44:28 -0400 From: Mark Cave-Ayland Date: Sat, 9 Apr 2016 12:43:32 +0100 Message-Id: <1460202212-14946-1-git-send-email-mark.cave-ayland@ilande.co.uk> Subject: [Qemu-devel] [PATCH for-2.6] target-sparc: fix ldstub sign-extension bug List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, peter.maydell@linaro.org, rth@twiddle.net, atar4qemu@gmail.com ldstub [addr], reg incorrectly reads a signed byte from memory which causes problems in the 32-bit Solaris mutex code. Here the byte value being read is 0xff which is incorrectly sign-extended to 0xffffffff before being written back to the target register causing lock detection to behave incorrectly. This fixes the intermittent hangs and MUTEX_HELD warnings issued to the console when running 32-bit Solaris images under qemu-system-sparc. With thanks to Joseph Dery for providing a condensed test image to consistently reproduce the problem on demand, and Martin Husemann for allowing me access to real hardware for comparison. Signed-off-by: Mark Cave-Ayland --- target-sparc/translate.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/target-sparc/translate.c b/target-sparc/translate.c index 58572c3..7998ff5 100644 --- a/target-sparc/translate.c +++ b/target-sparc/translate.c @@ -4670,7 +4670,7 @@ static void disas_sparc_insn(DisasContext * dc, unsigned int insn) TCGv r_const; gen_address_mask(dc, cpu_addr); - tcg_gen_qemu_ld8s(cpu_val, cpu_addr, dc->mem_idx); + tcg_gen_qemu_ld8u(cpu_val, cpu_addr, dc->mem_idx); r_const = tcg_const_tl(0xff); tcg_gen_qemu_st8(r_const, cpu_addr, dc->mem_idx); tcg_temp_free(r_const); -- 1.7.10.4