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[2001:1868:205::9]) by mx.google.com with ESMTPS id x4si9963583pfa.54.2016.08.24.07.39.54 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 24 Aug 2016 07:39:55 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-arm-kernel-bounces+patch=linaro.org@lists.infradead.org designates 2001:1868:205::9 as permitted sender) client-ip=2001:1868:205::9; Authentication-Results: mx.google.com; dkim=neutral (body hash did not verify) header.i=@linaro.org; spf=pass (google.com: best guess record for domain of linux-arm-kernel-bounces+patch=linaro.org@lists.infradead.org designates 2001:1868:205::9 as permitted sender) smtp.mailfrom=linux-arm-kernel-bounces+patch=linaro.org@lists.infradead.org; dmarc=fail (p=NONE dis=NONE) header.from=linaro.org Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.85_2 #1 (Red Hat Linux)) id 1bcZKB-0006V8-2y; Wed, 24 Aug 2016 14:38:39 +0000 Received: from mail-wm0-x22e.google.com ([2a00:1450:400c:c09::22e]) by bombadil.infradead.org with esmtps (Exim 4.85_2 #1 (Red Hat Linux)) id 1bcZIN-0005L9-44 for linux-arm-kernel@lists.infradead.org; Wed, 24 Aug 2016 14:36:52 +0000 Received: by mail-wm0-x22e.google.com with SMTP id o80so31372624wme.1 for ; Wed, 24 Aug 2016 07:36:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=jda201z1lxyJ4USiAPXboMs0QinBfkSnE7ke2YigVro=; b=LUpZH2Ozy+2IAtdiEFlOuS/nFMo5NxbJ3tw6YLYqa5kkbvqznu/t4ElcdoOU6CXoQW eCGnZhMtUmr9/9FO0t2twriO4quC3Zh23E4EWYaJkPJOr5LJVUL87Z6QGBy6kxylcmQa w78lzrsOC0MOwooX+z/Adh4lpbGPvp1RKGr60= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=jda201z1lxyJ4USiAPXboMs0QinBfkSnE7ke2YigVro=; b=F9n93cKbG1a0WQCwUlVCUItvdUZTorOlLOXeoyBeeHSGJZ4p2tXddgdkGjSPj5LI2k pUG7P/xqnPZoCP8gPC8aR9V1Kx3gzjY8jjseeUeQQyFiJNzUh+Vbpg6rNkOcwmICAomu aqqGIH1R8/uKFWlMYys/g7Yg6QasUfIle8Qk3+BoLaoiyLHnFh/CogRM/dcWbuXAytHs wvPVtte00unyq3ZyDPOrKgNO9DVWjsGH2z8Xfjbt2+k6Kwjh5P5ItN2+jI7d/24/a1+I GbAwuT1Jx2euQBQihUkyBKRi7ITOlYlT+v9ZfPJoCagvXc9FntlyCKjx2J7EkNxbI+/C rjSA== X-Gm-Message-State: AEkooutyljExqvoQbNu4zXi6WcKqmY5/Ln5XpK+yaW22ULN+aDOIWUpdgzWga+GQ0HH3nEw/ X-Received: by 10.28.69.203 with SMTP id l72mr25807476wmi.51.1472049389999; Wed, 24 Aug 2016 07:36:29 -0700 (PDT) Received: from localhost.localdomain ([213.143.60.123]) by smtp.gmail.com with ESMTPSA id n2sm10365569wjd.1.2016.08.24.07.36.28 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Wed, 24 Aug 2016 07:36:29 -0700 (PDT) From: Ard Biesheuvel To: linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com, will.deacon@arm.com, mark.rutland@arm.com, james.morse@arm.com Subject: [PATCH v2 9/9] arm64: head.S: document the use of callee saved registers Date: Wed, 24 Aug 2016 16:36:06 +0200 Message-Id: <1472049366-10922-10-git-send-email-ard.biesheuvel@linaro.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1472049366-10922-1-git-send-email-ard.biesheuvel@linaro.org> References: <1472049366-10922-1-git-send-email-ard.biesheuvel@linaro.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20160824_073647_644415_A01E9825 X-CRM114-Status: UNSURE ( 9.68 ) X-CRM114-Notice: Please train this message. X-Spam-Score: -2.7 (--) X-Spam-Report: SpamAssassin version 3.4.0 on bombadil.infradead.org summary: Content analysis details: (-2.7 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at http://www.dnswl.org/, low trust [2a00:1450:400c:c09:0:0:0:22e listed in] [list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Ard Biesheuvel MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patch=linaro.org@lists.infradead.org Now that the only remaining occurrences of the use of callee saved registers are on the primary boot path, add a comment to the code which register is used for what. Signed-off-by: Ard Biesheuvel --- arch/arm64/kernel/head.S | 10 ++++++++++ 1 file changed, 10 insertions(+) -- 2.7.4 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel Reviewed-by: Mark Rutland diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index ad1dc61d67ac..8bc9458f9add 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -208,6 +208,16 @@ efi_header_end: __INIT + /* + * The following callee saved general purpose registers are used on the + * primary lowlevel boot path: + * + * Register Scope Purpose + * x21 stext() .. start_kernel() FDT pointer passed at boot in x0 + * x23 stext() .. start_kernel() physical misalignment/KASLR offset + * x28 __create_page_tables() callee preserved temp register + * x19/x20 __primary_switch() callee preserved temp registers + */ ENTRY(stext) bl preserve_boot_args bl el2_setup // Drop to EL1, w0=cpu_boot_mode