Re: [PATCH 1/2] riscv: vdso: Do not use LTO for the vDSO

From: Paul Walmsley <pjw@kernel.org>
To: "Thomas Weißschuh" <thomas.weissschuh@linutronix.de>
Cc: Paul Walmsley <pjw@kernel.org>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	 Albert Ou <aou@eecs.berkeley.edu>,
	Alexandre Ghiti <alex@ghiti.fr>,
	 Nathan Chancellor <nathan@kernel.org>,
	 Conor Dooley <conor.dooley@microchip.com>,
	Wende Tan <twd2.me@gmail.com>,
	 Palmer Dabbelt <palmer@rivosinc.com>,
	linux-riscv@lists.infradead.org,  linux-kernel@vger.kernel.org,
	Nam Cao <namcao@linutronix.de>,
	 kernel test robot <lkp@intel.com>,
	stable@vger.kernel.org
Subject: Re: [PATCH 1/2] riscv: vdso: Do not use LTO for the vDSO
Date: Mon, 13 Jul 2026 12:14:53 -0600 (MDT)	[thread overview]
Message-ID: <541aed79-b153-726c-87f9-cfd9f9304c46@kernel.org> (raw)
In-Reply-To: <20260701-riscv-vdso-lto-v1-1-89db0cd82077@linutronix.de>

[-- Attachment #1: Type: text/plain, Size: 724 bytes --]

On Wed, 1 Jul 2026, Thomas Weißschuh wrote:

> With LTO enabled the compiler assumes that the vDSO functions are not
> used and optimizes them away completely. Currently this happens to
> __vdso_clock_getres(), __vdso_clock_gettime(), __vdso_getrandom(),
> __vdso_gettimeofday() and __vdso_riscv_hwprobe().
> 
> Disable LTO for the vDSO, as these functions are hand-optimized anyways.
> 
> Reported-by: kernel test robot <lkp@intel.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202606301855.WvkSC4kD-lkp@intel.com/
> Fixes: 021d23428bdb ("RISC-V: build: Allow LTO to be selected")
> Cc: stable@vger.kernel.org
> Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>

Thanks, queued for v7.2-rc.

- Paul

[-- Attachment #2: Type: text/plain, Size: 161 bytes --]

_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv