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Date: Mon, 26 Aug 2024 22:55:41 +0200
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
To: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Cc: Theodore Ts'o <tytso@mit.edu>, linux-kernel@vger.kernel.org,
	linux-crypto@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-arch@vger.kernel.org,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>, Thomas Gleixner <tglx@linutronix.de>,
	Eric Biggers <ebiggers@kernel.org>,
	Christophe Leroy <christophe.leroy@csgroup.eu>
Subject: Re: [PATCH] aarch64: vdso: Wire up getrandom() vDSO implementation
Message-ID: <ZszrzRbL-eks6A3I@zx2c4.com>
References: <20240826181059.111536-1-adhemerval.zanella@linaro.org>
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In-Reply-To: <20240826181059.111536-1-adhemerval.zanella@linaro.org>

On Mon, Aug 26, 2024 at 06:10:40PM +0000, Adhemerval Zanella wrote:
> +static __always_inline ssize_t getrandom_syscall(void *buffer, size_t len, unsigned int flags)
> +{
> +	register long int x8 asm ("x8") = __NR_getrandom;
> +	register long int x0 asm ("x0") = (long int) buffer;
> +	register long int x1 asm ("x1") = (long int) len;
> +	register long int x2 asm ("x2") = (long int) flags;
> +
> +	asm ("svc 0" : "=r"(x0) : "r"(x8), "0"(x0), "r"(x1), "r"(x2));
> +
> +	return x0;
> +}

More generally, it might be best to follow the format used by
arch/arm64/include/asm/vdso/gettimeofday.h.