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From: "Philippe Mathieu-Daudé" <philmd@linaro.org>
To: qemu-devel@nongnu.org
Cc: "Christoph Muellner" <christoph.muellner@vrull.eu>,
	"Heinrich Schuchardt" <heinrich.schuchardt@canonical.com>,
	"Palmer Dabbelt" <palmer@dabbelt.com>,
	"Alistair Francis" <alistair.francis@wdc.com>,
	"Liu Zhiwei" <zhiwei_liu@linux.alibaba.com>,
	"Anton Johansson" <anjo@rev.ng>,
	"Richard Henderson" <richard.henderson@linaro.org>,
	"Valentin Haudiquet" <valentin.haudiquet@canonical.com>,
	"Weiwei Li" <liwei1518@gmail.com>,
	qemu-riscv@nongnu.org,
	"Daniel Henrique Barboza" <dbarboza@ventanamicro.com>,
	"Philippe Mathieu-Daudé" <philmd@linaro.org>,
	"Fabien Portas" <fabien.portas@grenoble-inp.org>,
	"Frédéric Pétrot" <frederic.petrot@univ-grenoble-alpes.fr>
Subject: [PATCH 01/13] target/riscv: Really use little endianness for 128-bit loads/stores
Date: Fri, 10 Oct 2025 17:50:32 +0200	[thread overview]
Message-ID: <20251010155045.78220-2-philmd@linaro.org> (raw)
In-Reply-To: <20251010155045.78220-1-philmd@linaro.org>

Per commit a2f827ff4f4 ("target/riscv: accessors to registers upper
part and 128-bit load/store") description:

 > The 128-bit ISA adds ldu, lq and sq. We provide support for these
 > instructions. Note that (a) we compute only 64-bit addresses to
 > actually access memory, cowardly utilizing the existing address
 > translation mechanism of QEMU, and (b) we assume for now
 > little-endian memory accesses.

   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

However this commit used MO_TE (target endianness) for the
gen_load_i128() and gen_store_i128() helpers. Likely it was
unnoticed because current targets are only built using little
endianness:

  $ git grep -L TARGET_BIG_ENDIAN=y configs/targets/riscv*
  configs/targets/riscv32-linux-user.mak
  configs/targets/riscv32-softmmu.mak
  configs/targets/riscv64-bsd-user.mak
  configs/targets/riscv64-linux-user.mak
  configs/targets/riscv64-softmmu.mak

Replace by MO_TE -> MO_LE to really use little endianness.

Cc: Fabien Portas <fabien.portas@grenoble-inp.org>
Cc: Frédéric Pétrot <frederic.petrot@univ-grenoble-alpes.fr>
Fixes: a2f827ff4f4 ("target/riscv: accessors to registers upper part and 128-bit load/store")
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
 target/riscv/insn_trans/trans_rvi.c.inc | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/target/riscv/insn_trans/trans_rvi.c.inc b/target/riscv/insn_trans/trans_rvi.c.inc
index b9c71604687..df0b555176a 100644
--- a/target/riscv/insn_trans/trans_rvi.c.inc
+++ b/target/riscv/insn_trans/trans_rvi.c.inc
@@ -389,9 +389,11 @@ static bool gen_load_i128(DisasContext *ctx, arg_lb *a, MemOp memop)
         }
     } else {
         /* assume little-endian memory access for now */
-        tcg_gen_qemu_ld_tl(destl, addrl, ctx->mem_idx, MO_TEUQ);
+        MemOp memop = MO_LEUQ;
+
+        tcg_gen_qemu_ld_tl(destl, addrl, ctx->mem_idx, memop);
         tcg_gen_addi_tl(addrl, addrl, 8);
-        tcg_gen_qemu_ld_tl(desth, addrl, ctx->mem_idx, MO_TEUQ);
+        tcg_gen_qemu_ld_tl(desth, addrl, ctx->mem_idx, memop);
     }
 
     gen_set_gpr128(ctx, a->rd, destl, desth);
@@ -494,9 +496,11 @@ static bool gen_store_i128(DisasContext *ctx, arg_sb *a, MemOp memop)
         tcg_gen_qemu_st_tl(src2l, addrl, ctx->mem_idx, memop);
     } else {
         /* little-endian memory access assumed for now */
-        tcg_gen_qemu_st_tl(src2l, addrl, ctx->mem_idx, MO_TEUQ);
+        MemOp memop = MO_LEUQ;
+
+        tcg_gen_qemu_st_tl(src2l, addrl, ctx->mem_idx, memop);
         tcg_gen_addi_tl(addrl, addrl, 8);
-        tcg_gen_qemu_st_tl(src2h, addrl, ctx->mem_idx, MO_TEUQ);
+        tcg_gen_qemu_st_tl(src2h, addrl, ctx->mem_idx, memop);
     }
     return true;
 }
-- 
2.51.0



  reply	other threads:[~2025-10-10 15:54 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-10-10 15:50 [PATCH 00/13] target/riscv: Centralize MO_TE uses in a pair of helpers Philippe Mathieu-Daudé
2025-10-10 15:50 ` Philippe Mathieu-Daudé [this message]
2025-10-10 18:44   ` [PATCH 01/13] target/riscv: Really use little endianness for 128-bit loads/stores Richard Henderson
2025-10-10 15:50 ` [PATCH 02/13] target/riscv: Explode MO_TExx -> MO_TE | MO_xx Philippe Mathieu-Daudé
2025-10-10 18:45   ` Richard Henderson
2025-10-14  4:59   ` Alistair Francis
2025-10-10 15:50 ` [PATCH 03/13] target/riscv: Conceal MO_TE within gen_amo() Philippe Mathieu-Daudé
2025-10-10 18:46   ` Richard Henderson
2025-10-14  5:00   ` Alistair Francis
2025-10-10 15:50 ` [PATCH 04/13] target/riscv: Conceal MO_TE within gen_inc() Philippe Mathieu-Daudé
2025-10-10 18:47   ` Richard Henderson
2025-10-14  5:01   ` Alistair Francis
2025-10-10 15:50 ` [PATCH 05/13] target/riscv: Conceal MO_TE within gen_load() / gen_store() Philippe Mathieu-Daudé
2025-10-10 18:47   ` Richard Henderson
2025-10-14  5:02   ` Alistair Francis
2025-10-10 15:50 ` [PATCH 06/13] target/riscv: Conceal MO_TE within gen_load_idx() / gen_store_idx() Philippe Mathieu-Daudé
2025-10-10 18:48   ` Richard Henderson
2025-10-14  5:03   ` Alistair Francis
2025-10-10 15:50 ` [PATCH 07/13] target/riscv: Conceal MO_TE within gen_fload_idx() / gen_fstore_idx() Philippe Mathieu-Daudé
2025-10-10 18:49   ` Richard Henderson
2025-10-14  5:05   ` Alistair Francis
2025-10-10 15:50 ` [PATCH 08/13] target/riscv: Conceal MO_TE within gen_storepair_tl() Philippe Mathieu-Daudé
2025-10-10 18:49   ` Richard Henderson
2025-10-14  5:06   ` Alistair Francis
2025-10-10 15:50 ` [PATCH 09/13] target/riscv: Conceal MO_TE within gen_cmpxchg*() Philippe Mathieu-Daudé
2025-10-10 18:50   ` Richard Henderson
2025-10-14  5:07   ` Alistair Francis
2025-10-10 15:50 ` [PATCH 10/13] target/riscv: Conceal MO_TE|MO_ALIGN within gen_lr() / gen_sc() Philippe Mathieu-Daudé
2025-10-10 18:51   ` Richard Henderson
2025-10-14  5:08   ` Alistair Francis
2025-10-10 15:50 ` [PATCH 11/13] target/riscv: Factor MemOp variable out when MO_TE is set Philippe Mathieu-Daudé
2025-10-10 16:18   ` Heinrich Schuchardt
2025-10-14  5:11   ` Alistair Francis
2025-10-10 15:50 ` [PATCH 12/13] target/riscv: Introduce mo_endian() helper Philippe Mathieu-Daudé
2025-10-10 16:35   ` Heinrich Schuchardt
2025-10-10 18:52   ` Richard Henderson
2025-10-14  5:13   ` Alistair Francis
2025-10-10 15:50 ` [PATCH 13/13] target/riscv: Introduce mo_endian_env() helper Philippe Mathieu-Daudé
2025-10-10 16:38   ` Heinrich Schuchardt
2025-10-14  5:15   ` Alistair Francis

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