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Date: Mon, 19 Aug 2024 13:03:17 +0000
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
To: Huacai Chen <chenhuacai@kernel.org>
Cc: Xi Ruoyao <xry111@xry111.site>, WANG Xuerui <kernel@xen0n.name>,
	linux-crypto@vger.kernel.org, loongarch@lists.linux.dev,
	Jinyang He <hejinyang@loongson.cn>,
	Tiezhu Yang <yangtiezhu@loongson.cn>, Arnd Bergmann <arnd@arndb.de>
Subject: Re: [PATCH v3 1/3] LoongArch: vDSO: Wire up getrandom() vDSO
 implementation
Message-ID: <ZsNClVFzfi3djXDz@zx2c4.com>
References: <20240816110717.10249-1-xry111@xry111.site>
 <20240816110717.10249-2-xry111@xry111.site>
 <CAAhV-H7TKg98QXtrv9UmzZd9O=pxERvzCsz83Y+m+kf0zbeCkA@mail.gmail.com>
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> > The compiler (GCC 14.2) calls memset() for initializing a "large" struct
> > in a cold path of the generic vDSO getrandom() code.  There seems no way
> > to prevent it from calling memset(), and it's a cold path so the
> > performance does not matter, so just provide a naive memset()
> > implementation for vDSO.
> Why x86 doesn't need to provide a naive memset()?

It looks like others are running into this when porting to ppc and
arm64, so I'll probably refactor the code to avoid needing it in the
first place. I'll chime in here when that's done.

Jason