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Wed, 12 May 2021 16:31:37 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id 91B7261285; Wed, 12 May 2021 16:31:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1620837096; bh=xk65L3jLbqgiz9vtK9IChWm1UnClmnD46yJGQYe1g5c=; h=From:To:Cc:Subject:Date:From; b=SLmDgiGix338wAhRnz7Wp9+RqnDisEu8eHX8OFyyyCSCM8azw3HDyveUK2Wqvnrqp snJRTGjnEC3/p1QnVYOZCLB/mmUSWcoQSS42OjrYtmevKSyE0EMP8RiQYHWzTKOJCY EpSSXokw+OOyNdu7nm72S3+AQI52ZLcF1M9FxQlgmWHU4gUqiYXdkkY4WYIvJ3QHn7 6glU/J+Wnm1Pr2jMHpJSu/E1rSz3dPd2FLUWAKap4FXV4KT6gtsX3cfx/IBX2FZwHi d0l3URVXh98LQHtwdtHDJ0BVFz8mRfROg419gYxXRlpSCeojez/CnHnr4EqKWCoUc8 Gvj4wxMCKSFlw== From: Mark Brown To: Catalin Marinas , Will Deacon Cc: linux-arm-kernel@lists.infradead.org, Marc Zyngier , Mark Brown Subject: [PATCH] arm64: Document requirement for access to FEAT_HCX Date: Wed, 12 May 2021 17:23:50 +0100 Message-Id: <20210512162350.20349-1-broonie@kernel.org> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 X-Patch-Hashes: v=1; h=sha256; i=YT16G/k47SJW19dlRIgWcgWQZ3BwP44W5ZYxRO8UNEY=; m=w0gARgPfyeh0X75VVp60egJBOpH57KV6u8FfwEkIH0w=; p=ImyzC0trUBILG5TKs9Yl55UUhvo0Qrk+IKtdtU7CO4c=; g=25feeebe42602fbfe531f229bbe77e1c2013c38e X-Patch-Sig: m=pgp; i=broonie@kernel.org; s=0xC3F436CA30F5D8EB; b=iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmCcAHgACgkQJNaLcl1Uh9CV4wf+JDB MG0owzSwvxtRXduGOg25C4+aFvtBtQ+aKdIw9bpel0kEYgqFdA6KCLZadg0zwGsEp31iEqbfHP6/w d28BINA0AyQ/Ozvi07TRVXSoS/urwNfSbMWiddCIGhTXk7IoBHrtiHcE5PaTstowbI0WTUKnqFhhW xDmyf+rrbXJtBdlZNmc3tblyQgZJ6iWtZAwWiG4jdafquKg1xzy0xr08+lvgoudnewKGJiBmulLH1 g1MZiRbpr7DcQuoYuHzVMsvHVHCq8qqzmrE7PE+PE/jrJTu5VNLlLwSUzdYx4nTCi8+wJdEXHdAWs RAqkeezRlIGORyh2NEgUFvKPd3BKjtg== X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210512_093136_877371_24A5CFDB X-CRM114-Status: UNSURE ( 9.21 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org v8.7 of the architecture introduced FEAT_HCX which adds an additional hypervisor configuration register HCRX_EL2. Even though Linux does not currently make use of this feature let's document that the EL3 trap for access to the register should be disabled so that we are able to make use of it in future. Signed-off-by: Mark Brown --- Documentation/arm64/booting.rst | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/Documentation/arm64/booting.rst b/Documentation/arm64/booting.rst index 18b8cc1bf32c..a9192e7a231b 100644 --- a/Documentation/arm64/booting.rst +++ b/Documentation/arm64/booting.rst @@ -277,6 +277,12 @@ Before jumping into the kernel, the following conditions must be met: - SCR_EL3.FGTEn (bit 27) must be initialised to 0b1. + For CPUs with support for HCRX_EL2 (FEAT_HCX) present: + + - If EL3 is present and the kernel is entered at EL2: + + - SCR_EL3.HXEn (bit 38) must be initialised to 0b1. + For CPUs with Advanced SIMD and floating point support: - If EL3 is present: -- 2.20.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel