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a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Br+eku/wpkIoP2nzQJSV3xybmY5NP9A44mET6BqLXXA=; b=r4Nez/yRBedkNcvnPNemxd2XXNNRJjgjUkmyGnOyDGuROrnMDRtY6AkIGBZvXQ8dm1 QvRSVomEXrs37iMrGpTXPBu7PX9cXOMMOhbGZnf3IOTAzbwV4UuTHvzdH3m14annVIHq ifuPr+gO+itcb4WknjVjJTiDWwwBteWKJWzyKFvdgk6/GEMjElKYBiKFOADleDP/Z1Yg VbyOgrCy9PNQL58G9bWg2j2Y0kQ7SlG9lczM4WBp/Rg87fcGAU5er85y8JC4Oc615Uz1 j2JaqDG6qH88nzI6CEQZniYqax2FnFWj3DOVFhq8TYD8H51y+5hUUb60SBN/UFkBj+Ma 5urQ== X-Gm-Message-State: APjAAAW0owMxe9BFA+lI2onwXCJjYPAQtfgWh2DSudVMZUdwhmSSXzdq OBfx7mO3o3r9kXeFNzvwgYjGmDQJRVaORckUABiopg== X-Google-Smtp-Source: APXvYqx8sSaVLM2nTdpw1kDaD7H/K4VrWc33h4wJmq6CExmnkilGqmMWI+eunnORN41z/Ae8o0PoQOqIyEY5nf5j0Jw= X-Received: by 2002:a1c:7205:: with SMTP id n5mr32844152wmc.9.1579074057402; Tue, 14 Jan 2020 23:40:57 -0800 (PST) MIME-Version: 1.0 References: <20200110122341.8445-1-broonie@kernel.org> <20200110122341.8445-2-broonie@kernel.org> <20200114174432.GG2579@willie-the-truck> In-Reply-To: <20200114174432.GG2579@willie-the-truck> From: Ard Biesheuvel Date: Wed, 15 Jan 2020 08:40:46 +0100 Message-ID: Subject: Re: [PATCH v10 1/3] arm64: Implement archrandom.h for ARMv8.5-RNG To: Will Deacon X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200114_234100_849613_C16C3B3B X-CRM114-Status: GOOD ( 17.06 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Catalin Marinas , Mark Brown , Richard Henderson , linux-arm-kernel Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, 14 Jan 2020 at 18:44, Will Deacon wrote: > > On Fri, Jan 10, 2020 at 12:23:39PM +0000, Mark Brown wrote: > > From: Richard Henderson > > > > Expose the ID_AA64ISAR0.RNDR field to userspace, as the RNG system > > registers are always available at EL0. > > > > Implement arch_get_random_seed_long using RNDR. Given that the > > TRNG is likely to be a shared resource between cores, and VMs, > > do not explicitly force re-seeding with RNDRRS. In order to avoid > > code complexity and potential issues with hetrogenous systems only > > provide values after cpufeature has finalized the system capabilities. > > > > Signed-off-by: Richard Henderson > > [Modified to only function after cpufeature has finalized the system > > capabilities and move all the code into the header -- broonie] > > Signed-off-by: Mark Brown > > Reviewed-by: Mark Rutland > > --- > > Documentation/arm64/cpu-feature-registers.rst | 2 + > > arch/arm64/Kconfig | 12 ++++ > > arch/arm64/include/asm/archrandom.h | 67 +++++++++++++++++++ > > arch/arm64/include/asm/cpucaps.h | 3 +- > > arch/arm64/include/asm/sysreg.h | 4 ++ > > arch/arm64/kernel/cpufeature.c | 13 ++++ > > 6 files changed, 100 insertions(+), 1 deletion(-) > > create mode 100644 arch/arm64/include/asm/archrandom.h > > In which case, should we also add an HWCAP for this? > Isn't this covered by the 'cpuid' HWCAP? We can't prevent EL0 from accessing these system registers anyway, even if we wanted to. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel