From 4553e10360a0713e31647220ed396942f9a6fca0 Mon Sep 17 00:00:00 2001 From: Mark Cave-Ayland Date: Sat, 9 Apr 2016 12:25:12 +0100 Subject: [PATCH] target-sparc: fix ldstub sign-extension bug 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 Reviewed-By: Artyom Tarasenko 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 58572c34cf..7998ff57bf 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);