In commit c1a1f80518d360b when we added the FEAT_LSE2 relaxations to
the alignment requirements for atomic and ordered loads and stores,
we didn't quite get it right for LDAPR/LDAPRH/LDAPRB with no
immediate offset.  These instructions were handled in the old decoder
as part of disas_ldst_atomic(), but unlike all the other insns that
function decoded (LDADD, LDCLR, etc) these insns are "ordered", not
"atomic", so they should be using check_ordered_align() rather than
check_atomic_align().  Commit c1a1f80518d360b used
check_atomic_align() regardless for everything in
disas_ldst_atomic().  We then carried that incorrect check over in
the decodetree conversion, where LDAPR/LDAPRH/LDAPRB are now handled
by trans_LDAPR().

The effect is that when FEAT_LSE2 is implemented, these instructions
don't honour the SCTLR_ELx.nAA bit and will generate alignment
faults when they should not.

(The LDAPR insns with an immediate offset were in disas_ldst_ldapr_stlr()
and then in trans_LDAPR_i() and trans_STLR_i(), and have always used
the correct check_ordered_align().)

Use check_ordered_align() in trans_LDAPR().

Cc: qemu-stable@nongnu.org
Fixes: c1a1f80518d360b ("target/arm: Relax ordered/atomic alignment checks for LSE2")
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/arm/tcg/translate-a64.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index 6c07aeaf3bd..5ea204d5009 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -3543,7 +3543,7 @@ static bool trans_LDAPR(DisasContext *s, arg_LDAPR *a)
     if (a->rn == 31) {
         gen_check_sp_alignment(s);
     }
-    mop = check_atomic_align(s, a->rn, a->sz);
+    mop = check_ordered_align(s, a->rn, 0, false, a->sz);
     clean_addr = gen_mte_check1(s, cpu_reg_sp(s, a->rn), false,
                                 a->rn != 31, mop);
     /*
-- 
2.34.1

On 7/9/24 06:45, Peter Maydell wrote:
> In commit c1a1f80518d360b when we added the FEAT_LSE2 relaxations to
> the alignment requirements for atomic and ordered loads and stores,
> we didn't quite get it right for LDAPR/LDAPRH/LDAPRB with no
> immediate offset.  These instructions were handled in the old decoder
> as part of disas_ldst_atomic(), but unlike all the other insns that
> function decoded (LDADD, LDCLR, etc) these insns are "ordered", not
> "atomic", so they should be using check_ordered_align() rather than
> check_atomic_align().  Commit c1a1f80518d360b used
> check_atomic_align() regardless for everything in
> disas_ldst_atomic().  We then carried that incorrect check over in
> the decodetree conversion, where LDAPR/LDAPRH/LDAPRB are now handled
> by trans_LDAPR().
> 
> The effect is that when FEAT_LSE2 is implemented, these instructions
> don't honour the SCTLR_ELx.nAA bit and will generate alignment
> faults when they should not.
> 
> (The LDAPR insns with an immediate offset were in disas_ldst_ldapr_stlr()
> and then in trans_LDAPR_i() and trans_STLR_i(), and have always used
> the correct check_ordered_align().)
> 
> Use check_ordered_align() in trans_LDAPR().
> 
> Cc:qemu-stable@nongnu.org
> Fixes: c1a1f80518d360b ("target/arm: Relax ordered/atomic alignment checks for LSE2")
> Signed-off-by: Peter Maydell<peter.maydell@linaro.org>
> ---
>   target/arm/tcg/translate-a64.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>


r~