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Thu, 22 Jan 2026 10:58:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1769079489; bh=mlHWGTku+nmROG/IwYrYRxE/caYwAM8oVuKxSsjWjdg=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=jiVjYaHHxqriVs2o8gdR+pdPefWkgZrI1J7SdIfgivu3IM8JY7WMToxD6Dqlbgggv TcguLr6cCUZx1/jDarV8qtuzdLe+q9dPozHbFlXrbqsPgKM/XbEtZbLATenl5mJZyC xWCNjbEVfQ1cPulMHJ8bRBb+JEEyqZX/Lva9OHwDXo4sBc7y9iHjv/meUeoTFdrWY3 kWVnub+4WAiUPBuwjV+cssojl79uZa+UlC42hrfj8t2p93JdQ5G4RLRXJYCg9MHvwg 5s1HOGpzWG3t/qbN+qJcLrcNrXJNjm5TB3Mgl8yNSJ2/4xCSJ73X/6srkr0geT8Otl TpEXOQtQp7pQw== Message-ID: <230c749f-ebd6-4829-93ee-601d88000a45@kernel.org> Date: Thu, 22 Jan 2026 11:58:04 +0100 X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] powerpc/vdso: Provide clock_getres_time64() To: =?UTF-8?Q?Thomas_Wei=C3=9Fschuh?= , "Sverdlin, Alexander" Cc: "npiggin@gmail.com" , "luto@kernel.org" , "maddy@linux.ibm.com" , "tglx@kernel.org" , "mpe@ellerman.id.au" , "vincenzo.frascino@arm.com" , "linuxppc-dev@lists.ozlabs.org" , "linux-kernel@vger.kernel.org" References: <20260114-vdso-powerpc-align-v1-1-acf09373d568@linutronix.de> <20260122104257-3124dc96-5916-4d25-bbce-9b868b30ee18@linutronix.de> <20260122114217-79f13c16-0931-4c33-b68c-08e884a26004@linutronix.de> Content-Language: fr-FR From: "Christophe Leroy (CS GROUP)" In-Reply-To: <20260122114217-79f13c16-0931-4c33-b68c-08e884a26004@linutronix.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Le 22/01/2026 à 11:49, Thomas Weißschuh a écrit : > On Thu, Jan 22, 2026 at 11:27:43AM +0100, Christophe Leroy (CS GROUP) wrote: >> Hi Thomas, >> >> Le 22/01/2026 à 10:50, Thomas Weißschuh a écrit : >>> Hi Alexander, >>> >>> On Thu, Jan 22, 2026 at 09:39:09AM +0000, Sverdlin, Alexander wrote: >>>> Hi Thomas, Christophe, >>>> >>>> On Wed, 2026-01-14 at 08:26 +0100, Thomas Weißschuh wrote: >>>>> For consistency with __vdso_clock_gettime64() there should also be a >>>>> 64-bit variant of clock_getres(). This will allow the extension of >>>>> CONFIG_COMPAT_32BIT_TIME to the vDSO and finally the removal of 32-bit >>>>> time types from the kernel and UAPI. >>>>> >>>>> Signed-off-by: Thomas Weißschuh >>>> >>>> I've bisected this patch to cause the following build failure on my side: >>>> >>>> LDS arch/powerpc/kernel/vdso/vdso32.lds >>>> VDSO32A arch/powerpc/kernel/vdso/sigtramp32-32.o >>>> VDSO32A arch/powerpc/kernel/vdso/gettimeofday-32.o >>>> VDSO32A arch/powerpc/kernel/vdso/datapage-32.o >>>> VDSO32A arch/powerpc/kernel/vdso/cacheflush-32.o >>>> VDSO32A arch/powerpc/kernel/vdso/note-32.o >>>> VDSO32A arch/powerpc/kernel/vdso/getcpu-32.o >>>> VDSO32A arch/powerpc/kernel/vdso/getrandom-32.o >>>> VDSO32A arch/powerpc/kernel/vdso/vgetrandom-chacha-32.o >>>> VDSO32C arch/powerpc/kernel/vdso/vgettimeofday-32.o >>>> VDSO32C arch/powerpc/kernel/vdso/vgetrandom-32.o >>>> VDSO32A arch/powerpc/kernel/vdso/crtsavres-32.o >>>> VDSO32L arch/powerpc/kernel/vdso/vdso32.so.dbg >>>> arch/powerpc/kernel/vdso/vdso32.so.dbg: dynamic relocations are not supported >>>> make[2]: *** [arch/powerpc/kernel/vdso/Makefile:79: arch/powerpc/kernel/vdso/vdso32.so.dbg] Error 1 >>>> make[1]: *** [arch/powerpc/Makefile:388: vdso_prepare] Error 2 >>> >>> Thanks for the report! >>> >>>> Does it ring any bells? What could I try/test? >>> >>> Not immediately, but I'll look into it. >>> >>>> I'm using gcc-15.2.0 and binutils 2.45.1. >>> >>> Is this a toolchain from https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fcdn.kernel.org%2Fpub%2Ftools%2Fcrosstool%2F&data=05%7C02%7Cchristophe.leroy%40csgroup.eu%7C937051154ddf479721f708de59a3e01c%7C8b87af7d86474dc78df45f69a2011bb5%7C0%7C0%7C639046757528646789%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=qkl4zNfg2j%2F24vZV7nQ7LLDtxG0WbgaJc30kjHQZqpk%3D&reserved=0 ? >>> Could you also share your configuration? >> >> I've just been able to reproduce it with ppc64_defconfig + >> CONFIG_CC_OPTIMIZE_FOR_SIZE > > Thanks for the hint, no I can reproduce it, too. >> >> VDSO32L arch/powerpc/kernel/vdso/vdso32.so.dbg >> arch/powerpc/kernel/vdso/vdso32.so.dbg: dynamic relocations are not >> supported >> make[2]: *** [arch/powerpc/kernel/vdso/Makefile:79: >> arch/powerpc/kernel/vdso/vdso32.so.dbg] Error 1 >> make[1]: *** [arch/powerpc/Makefile:388: vdso_prepare] Error 2 >> make: *** [Makefile:248: __sub-make] Error 2 >> >> I'll investigate > > It seems the compiler decides to call memset(), which is not valid from the > vDSO. We are are using -ffreestanding. Disabling CONFIG_INIT_STACK_ALL_ZERO > fixes the issue. So I guess we should a) figure out why -ffreestanding does > not seem to work here and b) exclude the vDSO from the stack initialization > logic. > Ah, ok. Reminds me commit b91c8c42ffdd ("lib/vdso: Force inlining of __cvdso_clock_gettime_common()") Problem fixed with: diff --git a/lib/vdso/gettimeofday.c b/lib/vdso/gettimeofday.c index 95df0153f05ab..4399e143d43a5 100644 --- a/lib/vdso/gettimeofday.c +++ b/lib/vdso/gettimeofday.c @@ -421,7 +421,7 @@ static __maybe_unused __kernel_old_time_t __cvdso_time(__kernel_old_time_t *time #endif /* VDSO_HAS_TIME */ #ifdef VDSO_HAS_CLOCK_GETRES -static __maybe_unused +static __always_inline bool __cvdso_clock_getres_common(const struct vdso_time_data *vd, clockid_t clock, struct __kernel_timespec *res) { Christophe