| Message ID | 1460202212-14946-1-git-send-email-mark.cave-ayland@ilande.co.uk |
|---|---|
| State | New |
| Headers | show |
On Sat, Apr 9, 2016 at 1:43 PM, Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk> wrote: > 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 <mark.cave-ayland@ilande.co.uk> Reviewed-By: Artyom Tarasenko <atar4qemu@gmail.com> > --- > 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 >
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);
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 <mark.cave-ayland@ilande.co.uk> --- target-sparc/translate.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)