[PATCH] target/arm: Fix syndrome for FGT traps on ERET

[PATCH] target/arm: Fix syndrome for FGT traps on ERET

[Peter Maydell]

In commit 442c9d682c94fc2 when we converted the ERET, ERETAA, ERETAB
instructions to decodetree, the conversion accidentally lost the
correct setting of the syndrome register when taking a trap because
of the FEAT_FGT HFGITR_EL1.ERET bit.  Instead of reporting a correct
full syndrome value with the EC and IL bits, we only reported the low
two bits of the syndrome, because the call to syn_erettrap() got
dropped.

Fix the syndrome values for these traps by reinstating the
syn_erettrap() calls.

Fixes: 442c9d682c94fc2 ("target/arm: Convert ERET, ERETAA, ERETAB to decodetree")
Cc: qemu-stable@nongnu.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
Spotted by code inspection when I was looking at putting in
the ERET trap for FEAT_NV...
---
 target/arm/tcg/translate-a64.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index ad78b8b1202..41484d8ae54 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -1606,7 +1606,7 @@ static bool trans_ERET(DisasContext *s, arg_ERET *a)
         return false;
     }
     if (s->fgt_eret) {
-        gen_exception_insn_el(s, 0, EXCP_UDEF, 0, 2);
+        gen_exception_insn_el(s, 0, EXCP_UDEF, syn_erettrap(0), 2);
         return true;
     }
     dst = tcg_temp_new_i64();
@@ -1633,7 +1633,7 @@ static bool trans_ERETA(DisasContext *s, arg_reta *a)
     }
     /* The FGT trap takes precedence over an auth trap. */
     if (s->fgt_eret) {
-        gen_exception_insn_el(s, 0, EXCP_UDEF, a->m ? 3 : 2, 2);
+        gen_exception_insn_el(s, 0, EXCP_UDEF, syn_erettrap(a->m ? 3 : 2), 2);
         return true;
     }
     dst = tcg_temp_new_i64();
-- 
2.34.1

Re: [PATCH] target/arm: Fix syndrome for FGT traps on ERET

[Richard Henderson]

On 10/24/23 10:24, Peter Maydell wrote:
> In commit 442c9d682c94fc2 when we converted the ERET, ERETAA, ERETAB
> instructions to decodetree, the conversion accidentally lost the
> correct setting of the syndrome register when taking a trap because
> of the FEAT_FGT HFGITR_EL1.ERET bit.  Instead of reporting a correct
> full syndrome value with the EC and IL bits, we only reported the low
> two bits of the syndrome, because the call to syn_erettrap() got
> dropped.
> 
> Fix the syndrome values for these traps by reinstating the
> syn_erettrap() calls.
> 
> Fixes: 442c9d682c94fc2 ("target/arm: Convert ERET, ERETAA, ERETAB to decodetree")
> Cc: qemu-stable@nongnu.org
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

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

r~