From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D024A1A3BB9; Thu, 5 Sep 2024 20:41:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725568909; cv=none; b=qCaQkczc8dLk7XAiLFbV90s8/8Xx2M3kKWQc+AFrtnBLDdlumIvQ0YWLllGAul258iuiVQCd5t68Ap4y7FJpCT3/KATXmdTiAEw+9j2S5aaZOwu2uc7rpZLm363shHjbaE8LgeCqCT5vDKp/PSwIyjbEalA8oyS6+X6RvfuALQo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725568909; c=relaxed/simple; bh=1pTKkK+g3LwaTtJ584c38j5d6WNE2g/owBxKg20Z/ps=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=NZSKdCkfOWoYR+LV2AP2Al3M++Ij2ln0XHwZ0TTJt7QspiFhWN/1b47S8r06OgXO1X2stTG+oxD8iLDQ2QMdo86EYPupFyrzoY5D4IW9z1qx9v3B95OcD0InISzZLYCtNw+B9HHO/rbRcXqxMhjr4+MHb5DdepuKin62dDbnktk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b=Vmhr4xm1; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="Vmhr4xm1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 398A0C4CEC3; Thu, 5 Sep 2024 20:41:46 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="Vmhr4xm1" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1725568904; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=IeN0hion7E5T8bnC9bEQSPstkGSkSwCA9M/4YZOxoLs=; b=Vmhr4xm1Wp03ugcdrYba3ciO2c/OQp0oQM3tMCUeyv/y6IZN4vNwmCaOuwFQTFlZjTxzGh vyDmKYOWlgz6gVR/SY11McK85Ld05NIERlGr0h62hGj7fSc/8dsPEgJIDmwgO9QkzhtMl2 G9lC+jvPOPB9VCi02VaBflNkREEbT7Y= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id 48b42c3c (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Thu, 5 Sep 2024 20:41:44 +0000 (UTC) Date: Thu, 5 Sep 2024 22:41:40 +0200 From: "Jason A. Donenfeld" To: Christophe Leroy Cc: Andrew Morton , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Michael Ellerman , Nicholas Piggin , Naveen N Rao , Nathan Chancellor , Nick Desaulniers , Bill Wendling , Justin Stitt , Shuah Khan , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kselftest@vger.kernel.org, llvm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, Adhemerval Zanella , Xi Ruoyao Subject: Re: [PATCH v5 4/5] powerpc/vdso: Wire up getrandom() vDSO implementation on VDSO32 Message-ID: References: <1f49c2ce009f8b007ab0676fb41187b2d54f28b2.1725304404.git.christophe.leroy@csgroup.eu> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: On Thu, Sep 05, 2024 at 06:13:29PM +0200, Jason A. Donenfeld wrote: > > +/* > > + * The macro sets two stack frames, one for the caller and one for the callee > > + * because there are no requirement for the caller to set a stack frame when > > + * calling VDSO so it may have omitted to set one, especially on PPC64 > > + */ > > + > > +.macro cvdso_call funct > > + .cfi_startproc > > + PPC_STLU r1, -PPC_MIN_STKFRM(r1) > > + .cfi_adjust_cfa_offset PPC_MIN_STKFRM > > + mflr r0 > > + PPC_STLU r1, -PPC_MIN_STKFRM(r1) > > + .cfi_adjust_cfa_offset PPC_MIN_STKFRM > > + PPC_STL r0, PPC_MIN_STKFRM + PPC_LR_STKOFF(r1) > > + .cfi_rel_offset lr, PPC_MIN_STKFRM + PPC_LR_STKOFF > > + get_datapage r8 > > + addi r8, r8, VDSO_RNG_DATA_OFFSET > > + bl CFUNC(DOTSYM(\funct)) > > + PPC_LL r0, PPC_MIN_STKFRM + PPC_LR_STKOFF(r1) > > + cmpwi r3, 0 > > + mtlr r0 > > + addi r1, r1, 2 * PPC_MIN_STKFRM > > + .cfi_restore lr > > + .cfi_def_cfa_offset 0 > > + crclr so > > + bgelr+ > > + crset so > > + neg r3, r3 > > + blr > > + .cfi_endproc > > +.endm > > Can you figure out what's going on and send a fix, which I'll squash > into this commit? This doesn't work, but I wonder if something like it is what we want. I need to head out for the day, but here's what I've got. It's all wrong but might be of interest. diff --git a/arch/powerpc/include/asm/vdso/getrandom.h b/arch/powerpc/include/asm/vdso/getrandom.h index 501d6bb14e8a..acb271709d30 100644 --- a/arch/powerpc/include/asm/vdso/getrandom.h +++ b/arch/powerpc/include/asm/vdso/getrandom.h @@ -47,7 +47,8 @@ static __always_inline struct vdso_rng_data *__arch_get_vdso_rng_data(void) } ssize_t __c_kernel_getrandom(void *buffer, size_t len, unsigned int flags, void *opaque_state, - size_t opaque_len, const struct vdso_rng_data *vd); + size_t opaque_len, const struct vdso_data *vd, + const struct vdso_rng_data *vrd); #endif /* !__ASSEMBLY__ */ diff --git a/arch/powerpc/kernel/vdso/getrandom.S b/arch/powerpc/kernel/vdso/getrandom.S index a957cd2b2b03..bc49eb87cfd1 100644 --- a/arch/powerpc/kernel/vdso/getrandom.S +++ b/arch/powerpc/kernel/vdso/getrandom.S @@ -32,7 +32,7 @@ .cfi_rel_offset r2, PPC_MIN_STKFRM + STK_GOT #endif get_datapage r8 - addi r8, r8, VDSO_RNG_DATA_OFFSET + addi r9, r8, VDSO_RNG_DATA_OFFSET bl CFUNC(DOTSYM(\funct)) PPC_LL r0, PPC_MIN_STKFRM + PPC_LR_STKOFF(r1) #ifdef __powerpc64__ diff --git a/arch/powerpc/kernel/vdso/vgetrandom.c b/arch/powerpc/kernel/vdso/vgetrandom.c index 5f855d45fb7b..408c76036868 100644 --- a/arch/powerpc/kernel/vdso/vgetrandom.c +++ b/arch/powerpc/kernel/vdso/vgetrandom.c @@ -8,7 +8,10 @@ #include ssize_t __c_kernel_getrandom(void *buffer, size_t len, unsigned int flags, void *opaque_state, - size_t opaque_len, const struct vdso_rng_data *vd) + size_t opaque_len, const struct vdso_data *vd, + const struct vdso_rng_data *vrd) { - return __cvdso_getrandom_data(vd, buffer, len, flags, opaque_state, opaque_len); + if (IS_ENABLED(CONFIG_TIME_NS) && vd->clock_mode == VDSO_CLOCKMODE_TIMENS) + vrd = (void *)vrd + (1UL << CONFIG_PAGE_SHIFT); + return __cvdso_getrandom_data(vrd, buffer, len, flags, opaque_state, opaque_len); }