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([87.213.113.147]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-b728933429fsm231990266b.9.2025.11.06.06.49.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 06 Nov 2025 06:49:10 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1762440551; x=1763045351; darn=nongnu.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=I0etlvZbNwYaPLzX0lVKmatPCLOUs+kyAR7zZ+B1IME=; b=mmZ9O/0GnzfxUY609YRnb8oMkVNffqozPlFk2kGc7Et2rF+t5vEC1SoEkINbwQLOMo 1WX5S0EnT1arENr/MBU7JIeMdhTpuBGvOdTVONND2QZRG9jp/eAM3l8cqDf6bvj/xSfC 2LDB4VUTwd2nr6Y+Pr1sCYqEN1iSom+3F2mS2BpBVno+yuzoUtkfIKXHASfTvVVHZMHg ug8cp+TpD7VWlps5W2g/D1wuit5gyleppDixnp8wGFOZN8POqcSp7w6hdoGw9MvPumOL 1q1P7mg4pQ5/SQXl8YyxjcLqFE117S+HPGk1zgopHzWMhcwR2ZzlNVXb1F2rRqGqbPd7 DwNA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1762440551; x=1763045351; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=I0etlvZbNwYaPLzX0lVKmatPCLOUs+kyAR7zZ+B1IME=; b=ZsFJTZ5aSjcmOKMVbD0tvp9eM31e47tpzHzQXLjJ4PQfX3cdBX5AX5yfovoVWHrpjH w21cDS51Z1ig0PZyEIYxiyOhTWLlN/rKkU1ekSlJ+AOkfey1IcxuXFrXHAF9p/dPzoAg p/tz9y9/etWQVoPP03ZYAjS174bMA72h4ZlF1tJ9Ur6ba7uemYAwZISogkT8QQ1Uq3pB vqUy+OVDnr+KvUVNEi6MdcraC8a4kx2bIFibWtONE8AX8ESLuYD/kTLc48b2d2ngYQPh thfp9xeR+JGfgUQFKBCVZpdScwGQXQCQ8BJoiVyxyd7Cwy9onwnqqXkD30cHuVUaJ/Ty E6EA== X-Gm-Message-State: AOJu0Yx9FLjGcQP3DMU6nw+Dfz8U9pT5PTaLXLBq3ltax75+2KlEwZoQ t6H0OaPZXAw4w4iA5TZpCL2GFdkGnKFLIoKbhPx2gAZQEUroX1fQNCb3Khqw1b/FmAE5FTBWUHI P2pp9PsQ= X-Gm-Gg: ASbGnctxW/etyv9L1UI8K0/XkUx5Phi0v3DUPrtNybb6ZgkXAxeZH3PWfjoi/5orZZj oM3hEp4O9BJHutMxsKznvnU/3aWCqB2Sb6HMNc3hRaaIJZUSBwO5OKMntYLM1Mpt0oKsh7gpsu2 vf1zJlVj+vAIY5IV0CHxrfW+PZBZtMIwlWJLFGDUEyVbXyI6qxXiVjhEkSTOijGiwHoozqnB8Bn J0kSyIkYhLbHY7pS3lGwH4BNYctmgDh3c1VpliA/pnT6CGCMDBz5guPgC/BaPcbZ+3qYKDysQRD LkyyYlNahvqQ73IW8Rdfy8hA/ivBYEPesVyHDSvZac9pWiLrHyPbuPPY9pTZ/7QD5ZkwgFMNnHw WFm+Azo6jctpZtOsTmQ6bbCJiRPtGx+EFf+FmjyxUiUmdBkhDA+Z7D/ILAXlK2hmXqKUemuYCm3 xyYOiW+TUg0eZ7TMWdhqzcdTCoXg== X-Google-Smtp-Source: AGHT+IFrrrJcfx/rA/QRrXL/E51LYSIMvbrRvA35T2k2fxTbvQdqmLizVXJbhz/Z6HOV2kiTteQd0Q== X-Received: by 2002:a17:907:3e0b:b0:b70:b3cb:3b30 with SMTP id a640c23a62f3a-b726567fa67mr727274266b.59.1762440550804; Thu, 06 Nov 2025 06:49:10 -0800 (PST) From: Richard Henderson To: qemu-devel@nongnu.org Cc: gustavo.romero@linaro.org, Anton Johansson Subject: [PATCH] target/arm: Fix accidental write to TCG constant Date: Thu, 6 Nov 2025 15:49:09 +0100 Message-ID: <20251106144909.533997-1-richard.henderson@linaro.org> X-Mailer: git-send-email 2.43.0 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2a00:1450:4864:20::629; envelope-from=richard.henderson@linaro.org; helo=mail-ej1-x629.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @linaro.org) X-ZM-MESSAGEID: 1762440566521158500 Content-Type: text/plain; charset="utf-8" Currently an unpredictable movw such as movw pc, 0x123 results in the tinycode and_i32 $0x123,$0x123,$0xfffffffc mov_i32 pc,$0x123 exit_tb $0x0 which is clearly a bug, writing to a constant is incorrect and discards the result of the mask. Fix this by adding a temporary in store_reg(). Signed-off-by: Anton Johansson [rth: Avoid an extra temp and extra move.] Signed-off-by: Richard Henderson Reviewed-by: #=EF=BF=BD=00=EF=BF=BD Tested-by: Gustavo Romero --- target/arm/tcg/translate.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/target/arm/tcg/translate.c b/target/arm/tcg/translate.c index 5f64fed220..63735d9789 100644 --- a/target/arm/tcg/translate.c +++ b/target/arm/tcg/translate.c @@ -303,20 +303,23 @@ TCGv_i32 add_reg_for_lit(DisasContext *s, int reg, in= t ofs) marked as dead. */ void store_reg(DisasContext *s, int reg, TCGv_i32 var) { + uint32_t mask =3D 0; + if (reg =3D=3D 15) { - /* In Thumb mode, we must ignore bit 0. + /* + * In Thumb mode, we must ignore bit 0. * In ARM mode, for ARMv4 and ARMv5, it is UNPREDICTABLE if bits [= 1:0] * are not 0b00, but for ARMv6 and above, we must ignore bits [1:0= ]. * We choose to ignore [1:0] in ARM mode for all architecture vers= ions. */ - tcg_gen_andi_i32(var, var, s->thumb ? ~1 : ~3); + mask =3D s->thumb ? 1 : 3; s->base.is_jmp =3D DISAS_JUMP; s->pc_save =3D -1; } else if (reg =3D=3D 13 && arm_dc_feature(s, ARM_FEATURE_M)) { /* For M-profile SP bits [1:0] are always zero */ - tcg_gen_andi_i32(var, var, ~3); + mask =3D 3; } - tcg_gen_mov_i32(cpu_R[reg], var); + tcg_gen_andi_i32(cpu_R[reg], var, ~mask); } =20 /* --=20 2.43.0