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[37.24.206.209]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2ccf80a8870sm8681843a91.50.2024.07.23.03.43.48 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 23 Jul 2024 03:43:50 -0700 (PDT) X-Outflank-Mailman: Message body and most headers restored to incoming version X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 7341f0d0-48e0-11ef-bbfe-fd08da9f4363 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1721731431; x=1722336231; darn=lists.xenproject.org; h=content-transfer-encoding:autocrypt:subject:from:cc:to :content-language:user-agent:mime-version:date:message-id:from:to:cc :subject:date:message-id:reply-to; bh=g5RPxZe2RFyLqMXQQMiFiZ6CLJzA8c72EtMOO1ub+Fc=; b=IXwxhkOesLmrhmP5Tt+lS8zVZ+e/quf69ZgKbHlJoE0S7GfauTNaaQ/VqDjEsBReR6 3eXosXNuJOOz3zo614ifFSXfVpBjEAAT/ToowBlL1/vMF01rKVf/Tcb0f5wbv2UO8nA1 GOL+mbgsVczUVGC8uhEuWUZlJ2g6fVozCLWUJ3ChRn9lTOms0R+wpb4+ak7vCAINEDKK 6meMTeBrJDG4LS58Inic4NhhBr8YFXnrXOWBUoBbEaQIwgoAIdNEmKTd6uHk5bpTwN+x eVRjk+6rEdqhsL2T1aRB1odK9GWcZ8jLdk6eiZSF1LRfoO3MTx6mQ07aDWjdLGKirFiq knUw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1721731431; x=1722336231; h=content-transfer-encoding:autocrypt:subject:from:cc:to :content-language:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=g5RPxZe2RFyLqMXQQMiFiZ6CLJzA8c72EtMOO1ub+Fc=; b=J0IxrOwTln+ckyHv6wlMFimJI7yqse0Ly1f/tZFmD5YtUASz70o8PI+tLBObVJaQY6 ZcAUDCOI9p2bHLEUVpl1eky54XLjli/IRWsxUkD5uqJy12BpyX3v7B6ccsF80ddA/vXI Wc29fTBy6Gu12YfsOw9WwOso5i6NsHCemE+jHTyenFHke9EUxcWOlGqrLwyBq2YaNgnH H6UWecxXyygpGyRdZCSb/kBPTXfbn9vQWwweVry/xVqO1CdVhYP86d6lN4uKQO4hguCT KyRE2Q0hXuiC0BQWxqY0Z7EmNW9CanzIxqQdLZO3JRKAXR4mx5eR6qxanDsYxdruc/X8 3Zvw== X-Gm-Message-State: AOJu0YzXvbxYqRQUXrrviiZ2ypRoKE/xlhWl/C5Zz5CX0hBJ0gu6NKgJ BgbKG5dqYdD5c41XPkPAv0kc7PPsiY7z0waEHbnaSDi953KCAbGTDZD7snUAQCFMuEdqDWX01tg = X-Google-Smtp-Source: AGHT+IHUIJdbIBvfG0h3u5Aphg78JHfvr5Htf0Qg/3gV3fIVOOig8wfD3DWxgNr5y08MFeJXaRC3gA== X-Received: by 2002:a2e:930e:0:b0:2ef:22ef:a24e with SMTP id 38308e7fff4ca-2f01ea4b411mr18090301fa.10.1721731431006; Tue, 23 Jul 2024 03:43:51 -0700 (PDT) Message-ID: Date: Tue, 23 Jul 2024 12:43:44 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Content-Language: en-US To: "xen-devel@lists.xenproject.org" Cc: Andrew Cooper , =?UTF-8?Q?Roger_Pau_Monn=C3=A9?= From: Jan Beulich Subject: [PATCH RFC] x86/IOMMU: permit use of -save-temps Autocrypt: addr=jbeulich@suse.com; keydata= xsDiBFk3nEQRBADAEaSw6zC/EJkiwGPXbWtPxl2xCdSoeepS07jW8UgcHNurfHvUzogEq5xk hu507c3BarVjyWCJOylMNR98Yd8VqD9UfmX0Hb8/BrA+Hl6/DB/eqGptrf4BSRwcZQM32aZK 7Pj2XbGWIUrZrd70x1eAP9QE3P79Y2oLrsCgbZJfEwCgvz9JjGmQqQkRiTVzlZVCJYcyGGsD /0tbFCzD2h20ahe8rC1gbb3K3qk+LpBtvjBu1RY9drYk0NymiGbJWZgab6t1jM7sk2vuf0Py O9Hf9XBmK0uE9IgMaiCpc32XV9oASz6UJebwkX+zF2jG5I1BfnO9g7KlotcA/v5ClMjgo6Gl MDY4HxoSRu3i1cqqSDtVlt+AOVBJBACrZcnHAUSuCXBPy0jOlBhxPqRWv6ND4c9PH1xjQ3NP nxJuMBS8rnNg22uyfAgmBKNLpLgAGVRMZGaGoJObGf72s6TeIqKJo/LtggAS9qAUiuKVnygo 3wjfkS9A3DRO+SpU7JqWdsveeIQyeyEJ/8PTowmSQLakF+3fote9ybzd880fSmFuIEJldWxp Y2ggPGpiZXVsaWNoQHN1c2UuY29tPsJgBBMRAgAgBQJZN5xEAhsDBgsJCAcDAgQVAggDBBYC AwECHgECF4AACgkQoDSui/t3IH4J+wCfQ5jHdEjCRHj23O/5ttg9r9OIruwAn3103WUITZee e7Sbg12UgcQ5lv7SzsFNBFk3nEQQCACCuTjCjFOUdi5Nm244F+78kLghRcin/awv+IrTcIWF hUpSs1Y91iQQ7KItirz5uwCPlwejSJDQJLIS+QtJHaXDXeV6NI0Uef1hP20+y8qydDiVkv6l IreXjTb7DvksRgJNvCkWtYnlS3mYvQ9NzS9PhyALWbXnH6sIJd2O9lKS1Mrfq+y0IXCP10eS FFGg+Av3IQeFatkJAyju0PPthyTqxSI4lZYuJVPknzgaeuJv/2NccrPvmeDg6Coe7ZIeQ8Yj t0ARxu2xytAkkLCel1Lz1WLmwLstV30g80nkgZf/wr+/BXJW/oIvRlonUkxv+IbBM3dX2OV8 AmRv1ySWPTP7AAMFB/9PQK/VtlNUJvg8GXj9ootzrteGfVZVVT4XBJkfwBcpC/XcPzldjv+3 HYudvpdNK3lLujXeA5fLOH+Z/G9WBc5pFVSMocI71I8bT8lIAzreg0WvkWg5V2WZsUMlnDL9 mpwIGFhlbM3gfDMs7MPMu8YQRFVdUvtSpaAs8OFfGQ0ia3LGZcjA6Ik2+xcqscEJzNH+qh8V m5jjp28yZgaqTaRbg3M/+MTbMpicpZuqF4rnB0AQD12/3BNWDR6bmh+EkYSMcEIpQmBM51qM EKYTQGybRCjpnKHGOxG0rfFY1085mBDZCH5Kx0cl0HVJuQKC+dV2ZY5AqjcKwAxpE75MLFkr wkkEGBECAAkFAlk3nEQCGwwACgkQoDSui/t3IH7nnwCfcJWUDUFKdCsBH/E5d+0ZnMQi+G0A nAuWpQkjM1ASeQwSHEeAWPgskBQL Content-Transfer-Encoding: quoted-printable X-ZohoMail-DKIM: pass (identity @suse.com) X-ZM-MESSAGEID: 1721731458357116600 Content-Type: text/plain; charset="utf-8" Rather than invoking make for individual .i and/or .i targets, it may be desirable to simply add -save-temps to $(CFLAGS) for some (or all) source files. That, however, triggers a tautological compare warning with at least gcc13 / gcc14. Apparently such warnings are suppressed when the compiler knows they originate from macro context; use of -save-temps, however, splits translation steps, and compiling the output of pre-processing does not have that contextual information anymore. Hack around this by making both sides of the comparison just different enough for the compiler to no longer spot the tautology, without sacrificing the dual purpose of the assertion (type match at build time, value match at runtime). Of course as the compiler gets smarter, further obfuscation may be needed. Signed-off-by: Jan Beulich --- RFC: Of course this escalation spiral isn't a good game to play. Are there alternatives I'm overlooking? I don't think we want to use -Wno-tautological-compare. --- a/xen/arch/x86/include/asm/iommu.h +++ b/xen/arch/x86/include/asm/iommu.h @@ -60,12 +60,12 @@ extern struct iommu_ops iommu_ops; =20 # include # define iommu_call(ops, fn, args...) ({ \ - ASSERT((ops) =3D=3D &iommu_ops); \ + ASSERT((ops) =3D=3D (1 ? &iommu_ops : NULL)); \ alternative_call(iommu_ops.fn, ## args); \ }) =20 # define iommu_vcall(ops, fn, args...) ({ \ - ASSERT((ops) =3D=3D &iommu_ops); \ + ASSERT((ops) =3D=3D (1 ? &iommu_ops : NULL)); \ alternative_vcall(iommu_ops.fn, ## args); \ })