[PATCH] target/nios2 : Explicitly ask for target-endian loads and stores

[PATCH] target/nios2 : Explicitly ask for target-endian loads and stores

[Peter Maydell]

When we generate code for guest loads and stores, at the moment they
end up being requests for a host-endian access. So for target-system-nios2
(little endian) a load like
   ldw        r3,0(r4)
results on an x86 host in the TCG IR
   qemu_ld_a32_i32 r3,loc2,al+leul,0
but on s390 it is
   qemu_ld_a32_i32 r3,loc2,al+beul,0

The result is that guests don't work on big-endian hosts.

Use the MO_TE* memops rather than the plain ones.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1693
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
Presumably this got lost in a recent conversion somewhere,
but I can't figure out where, so maybe it's been broken much
longer...
---
 target/nios2/translate.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/target/nios2/translate.c b/target/nios2/translate.c
index a365ad8293b..4264c7ec6b4 100644
--- a/target/nios2/translate.c
+++ b/target/nios2/translate.c
@@ -436,19 +436,19 @@ static const Nios2Instruction i_type_instructions[] = {
     INSTRUCTION_FLG(gen_cmpxxsi, TCG_COND_GE),        /* cmpgei */
     INSTRUCTION_ILLEGAL(),
     INSTRUCTION_ILLEGAL(),
-    INSTRUCTION_FLG(gen_ldx, MO_UW),                  /* ldhu */
+    INSTRUCTION_FLG(gen_ldx, MO_TEUW),                /* ldhu */
     INSTRUCTION(andi),                                /* andi */
-    INSTRUCTION_FLG(gen_stx, MO_UW),                  /* sth */
+    INSTRUCTION_FLG(gen_stx, MO_TEUW),                /* sth */
     INSTRUCTION_FLG(gen_bxx, TCG_COND_GE),            /* bge */
-    INSTRUCTION_FLG(gen_ldx, MO_SW),                  /* ldh */
+    INSTRUCTION_FLG(gen_ldx, MO_TESW),                /* ldh */
     INSTRUCTION_FLG(gen_cmpxxsi, TCG_COND_LT),        /* cmplti */
     INSTRUCTION_ILLEGAL(),
     INSTRUCTION_ILLEGAL(),
     INSTRUCTION_NOP(),                                /* initda */
     INSTRUCTION(ori),                                 /* ori */
-    INSTRUCTION_FLG(gen_stx, MO_UL),                  /* stw */
+    INSTRUCTION_FLG(gen_stx, MO_TEUL),                /* stw */
     INSTRUCTION_FLG(gen_bxx, TCG_COND_LT),            /* blt */
-    INSTRUCTION_FLG(gen_ldx, MO_UL),                  /* ldw */
+    INSTRUCTION_FLG(gen_ldx, MO_TEUL),                /* ldw */
     INSTRUCTION_FLG(gen_cmpxxsi, TCG_COND_NE),        /* cmpnei */
     INSTRUCTION_ILLEGAL(),
     INSTRUCTION_ILLEGAL(),
@@ -468,19 +468,19 @@ static const Nios2Instruction i_type_instructions[] = {
     INSTRUCTION_FLG(gen_cmpxxui, TCG_COND_GEU),       /* cmpgeui */
     INSTRUCTION_ILLEGAL(),
     INSTRUCTION_ILLEGAL(),
-    INSTRUCTION_FLG(gen_ldx, MO_UW),                  /* ldhuio */
+    INSTRUCTION_FLG(gen_ldx, MO_TEUW),                /* ldhuio */
     INSTRUCTION(andhi),                               /* andhi */
-    INSTRUCTION_FLG(gen_stx, MO_UW),                  /* sthio */
+    INSTRUCTION_FLG(gen_stx, MO_TEUW),                /* sthio */
     INSTRUCTION_FLG(gen_bxx, TCG_COND_GEU),           /* bgeu */
-    INSTRUCTION_FLG(gen_ldx, MO_SW),                  /* ldhio */
+    INSTRUCTION_FLG(gen_ldx, MO_TESW),                /* ldhio */
     INSTRUCTION_FLG(gen_cmpxxui, TCG_COND_LTU),       /* cmpltui */
     INSTRUCTION_ILLEGAL(),
     INSTRUCTION_UNIMPLEMENTED(),                      /* custom */
     INSTRUCTION_NOP(),                                /* initd */
     INSTRUCTION(orhi),                                /* orhi */
-    INSTRUCTION_FLG(gen_stx, MO_SL),                  /* stwio */
+    INSTRUCTION_FLG(gen_stx, MO_TESL),                /* stwio */
     INSTRUCTION_FLG(gen_bxx, TCG_COND_LTU),           /* bltu */
-    INSTRUCTION_FLG(gen_ldx, MO_UL),                  /* ldwio */
+    INSTRUCTION_FLG(gen_ldx, MO_TEUL),                /* ldwio */
     INSTRUCTION(rdprs),                               /* rdprs */
     INSTRUCTION_ILLEGAL(),
     INSTRUCTION_FLG(handle_r_type_instr, 0),          /* R-Type */
-- 
2.34.1

Re: [PATCH] target/nios2 : Explicitly ask for target-endian loads and stores

[Philippe Mathieu-Daudé]

On 23/6/23 19:25, Peter Maydell wrote:
> When we generate code for guest loads and stores, at the moment they
> end up being requests for a host-endian access. So for target-system-nios2
> (little endian) a load like
>     ldw        r3,0(r4)
> results on an x86 host in the TCG IR
>     qemu_ld_a32_i32 r3,loc2,al+leul,0
> but on s390 it is
>     qemu_ld_a32_i32 r3,loc2,al+beul,0
> 
> The result is that guests don't work on big-endian hosts.
> 
> Use the MO_TE* memops rather than the plain ones.
> 
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1693
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
> Presumably this got lost in a recent conversion somewhere,
> but I can't figure out where, so maybe it's been broken much
> longer...
> ---
>   target/nios2/translate.c | 20 ++++++++++----------
>   1 file changed, 10 insertions(+), 10 deletions(-)

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>

Re: [PATCH] target/nios2 : Explicitly ask for target-endian loads and stores

[Richard Henderson]

On 6/23/23 19:25, Peter Maydell wrote:
> When we generate code for guest loads and stores, at the moment they
> end up being requests for a host-endian access. So for target-system-nios2
> (little endian) a load like
>     ldw        r3,0(r4)
> results on an x86 host in the TCG IR
>     qemu_ld_a32_i32 r3,loc2,al+leul,0
> but on s390 it is
>     qemu_ld_a32_i32 r3,loc2,al+beul,0
> 
> The result is that guests don't work on big-endian hosts.
> 
> Use the MO_TE* memops rather than the plain ones.
> 
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1693
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
> Presumably this got lost in a recent conversion somewhere,
> but I can't figure out where, so maybe it's been broken much
> longer...

It has been broken since initial commit: 032c76bc6f9 was already wrong.

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


r~

Re: [PATCH] target/nios2 : Explicitly ask for target-endian loads and stores

[Richard Henderson]

On 6/23/23 19:25, Peter Maydell wrote:
> When we generate code for guest loads and stores, at the moment they
> end up being requests for a host-endian access. So for target-system-nios2
> (little endian) a load like
>     ldw        r3,0(r4)
> results on an x86 host in the TCG IR
>     qemu_ld_a32_i32 r3,loc2,al+leul,0
> but on s390 it is
>     qemu_ld_a32_i32 r3,loc2,al+beul,0
> 
> The result is that guests don't work on big-endian hosts.
> 
> Use the MO_TE* memops rather than the plain ones.
> 
> Resolves:https://gitlab.com/qemu-project/qemu/-/issues/1693
> Signed-off-by: Peter Maydell<peter.maydell@linaro.org>
> ---
> Presumably this got lost in a recent conversion somewhere,
> but I can't figure out where, so maybe it's been broken much
> longer...
> ---
>   target/nios2/translate.c | 20 ++++++++++----------
>   1 file changed, 10 insertions(+), 10 deletions(-)

Queued to tcg-next, for lack of anything better.


r~