Solaris 8 appears to have a bug whereby it executes v9 MEMBAR
instructions when booting a freshly installed image. According
to the SPARC v8 architecture manual, whilst bits 13 and bits 12-0
of the "Read State Register Instructions" are notionally zero,
they are marked as unused (i.e. ignored).
Fixes: af25071c1d ("target/sparc: Move RDASR, STBAR, MEMBAR to decodetree")
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/3097
Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
Reviewed-by: Mark Cave-Ayland <mark.cave-ayl...@ilande.co.uk>
Tested-by: Mark Cave-Ayland <mark.cave-ayl...@ilande.co.uk>
---
target/sparc/translate.c | 5 ++++-
target/sparc/insns.decode | 13 ++++++++++++-
2 files changed, 16 insertions(+), 2 deletions(-)
diff --git a/target/sparc/translate.c b/target/sparc/translate.c
index 336583beab..ece393fffc 100644
--- a/target/sparc/translate.c
+++ b/target/sparc/translate.c
@@ -2823,12 +2823,15 @@ static bool trans_Tcc_i_v9(DisasContext *dc,
arg_Tcc_i_v9 *a)
return do_tcc(dc, a->cond, a->cc, a->rs1, true, a->i);
}
-static bool trans_STBAR(DisasContext *dc, arg_STBAR *a)
+static bool do_stbar(DisasContext *dc)
{
tcg_gen_mb(TCG_MO_ST_ST | TCG_BAR_SC);
return advance_pc(dc);
}
+TRANS(STBAR_v8, 32, do_stbar)
+TRANS(STBAR_v9, 64, do_stbar)
+
static bool trans_MEMBAR(DisasContext *dc, arg_MEMBAR *a)
{
if (avail_32(dc)) {
diff --git a/target/sparc/insns.decode b/target/sparc/insns.decode
index 9e39d23273..1b1b85e9c2 100644
--- a/target/sparc/insns.decode
+++ b/target/sparc/insns.decode
@@ -88,7 +88,7 @@ CALL 01 i:s30
{
[
- STBAR 10 00000 101000 01111 0 0000000000000
+ STBAR_v9 10 00000 101000 01111 0 0000000000000
MEMBAR 10 00000 101000 01111 1 000000 cmask:3 mmask:4
RDCCR 10 rd:5 101000 00010 0 0000000000000
@@ -107,6 +107,17 @@ CALL 01 i:s30
RDSTICK_CMPR 10 rd:5 101000 11001 0 0000000000000
RDSTRAND_STATUS 10 rd:5 101000 11010 0 0000000000000
]
+
+ # The v8 manual, section B.30 STBAR instruction, says
+ # bits [12:0] are ignored, but bit 13 must be 0.
+ # However, section B.28 Read State Register Instruction has a
+ # comment that RDASR with rs1 = 15, rd = 0 is STBAR. Here,
+ # bit 13 is also ignored and rd != 0 is merely reserved.
+ #
+ # Solaris 8 executes v9 MEMBAR instruction 0x8143e008 during boot.
+ # This confirms that bit 13 is ignored, as 0x8143c000 is STBAR.
+ STBAR_v8 10 ----- 101000 01111 - -------------
+
# Before v8, all rs1 accepted; otherwise rs1==0.
RDY 10 rd:5 101000 rs1:5 0 0000000000000
}
--
2.43.0
