From patchwork Tue Feb 4 12:05:38 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Thomas_Wei=C3=9Fschuh?= X-Patchwork-Id: 13959054 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 83450C02197 for ; Tue, 4 Feb 2025 12:16:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:Cc:To:In-Reply-To:References:Message-Id :MIME-Version:Subject:Date:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=jFJksmwwXWudpUOd52kXQ+kac5Jucptdy73rK/oE5FA=; b=wVKI6gOfrOTX/E uvbsVRnxj69ZPdsEuCihTmB3wdsGwMmvfFd3+2GzxlyZv72WWw12iR4ZJZUokqA/ebb1oSJFkfXmP lhJQ0vxbRum+Nprn4c49pyQR9qkavVWRs1mxClOTeBjwdFxaYNWGoU4slu9+yDeMk29P9dcmAzKvG uUPzHnl5gP3iXZULto5aJiFU4/uxVLD+3LYQOwUowapZfVs7f3pb+w/xnJ5v2T8PKUoxC2b0UrjdP iDo9D815PZpXKHQ7H/sfyNnHDO6+4pFGBGkKi35yJTensj5tFGFBwbFP0fwqyzCGAzOuuBVo1t92R 2kkvdLXWdAzOIA6gxcQA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tfHqS-00000000OOK-35Ck; Tue, 04 Feb 2025 12:16:00 +0000 Received: from galois.linutronix.de ([193.142.43.55]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tfHgz-00000000LKx-0gnj; Tue, 04 Feb 2025 12:06:15 +0000 From: =?utf-8?q?Thomas_Wei=C3=9Fschuh?= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1738670769; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=8/4Eamx7aNctQ2PVRu06x5JtFo62FPJ6w8GVVkokEaU=; b=gU3VZk1tswzMN5aAS1haWWN80hBzULa9dfUVscLiuP3Byw9YSrUaDeQlSQJpS65KwXB1dK yzGLSyvoIg2vnJPZfSx2dIbhFMhTx293Mg0hPBv6iFEJDcBHAgqvONumKAH2oYM9vqmF9o m4XIvTVJTnlybjzzf+NQA8JEc9D5EYTX+MAWYRLFcYmZuawp62YqDE9ebUNDprFrD846n7 ZCdk/QgTuzLOPnfu2aKjfkyiNuhgccXnOiwV+exTRTexkHIgIapJxdU6jNWmaLAFFlT4DH UnA9fNHQ029qkf2QJ/DL41hrEqKDK8yxgpmAEl9kfkHGOqEMI/pJakpXrLxpNA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1738670769; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=8/4Eamx7aNctQ2PVRu06x5JtFo62FPJ6w8GVVkokEaU=; b=Jljy/6nozneeAxZyTqOBcZ5c0Hkshk+feAumY4O8hzW0YK3+FYNLkTo4LGSPC2hUO0BIfG Omo/GIP2gu4c8SAw== Date: Tue, 04 Feb 2025 13:05:38 +0100 Subject: [PATCH v3 06/18] vdso: Add generic random data storage MIME-Version: 1.0 Message-Id: <20250204-vdso-store-rng-v3-6-13a4669dfc8c@linutronix.de> References: <20250204-vdso-store-rng-v3-0-13a4669dfc8c@linutronix.de> In-Reply-To: <20250204-vdso-store-rng-v3-0-13a4669dfc8c@linutronix.de> To: "James E.J. Bottomley" , Helge Deller , Andy Lutomirski , Thomas Gleixner , Vincenzo Frascino , Anna-Maria Behnsen , Frederic Weisbecker , Andrew Morton , Catalin Marinas , Will Deacon , Theodore Ts'o , "Jason A. Donenfeld" , Paul Walmsley , Palmer Dabbelt , Albert Ou , Huacai Chen , WANG Xuerui , Russell King , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Thomas Bogendoerfer , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Naveen N Rao , Madhavan Srinivasan , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Arnd Bergmann , Guo Ren Cc: linux-parisc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-riscv@lists.infradead.org, loongarch@lists.linux.dev, linux-s390@vger.kernel.org, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-arch@vger.kernel.org, Nam Cao , =?utf-8?q?Thom?= =?utf-8?q?as_Wei=C3=9Fschuh?= , linux-csky@vger.kernel.org X-Developer-Signature: v=1; a=ed25519-sha256; t=1738670761; l=7434; i=thomas.weissschuh@linutronix.de; s=20240209; h=from:subject:message-id; bh=esL609CqiCzQLEE84B6OgMfzgIhlQimUQfR9uontbrU=; b=EQSmxJeSGvIfdPcQ2kKR3d09IefAxX+Uz+t6uOTkw6bgsKysS66kCmQ84shanqobY3+v1nE/k m4nrVpK6htxDJ5GtELbKQ4fM2h1kBxpFy+awqeQ0QW0l2gpHq+FBpTQ X-Developer-Key: i=thomas.weissschuh@linutronix.de; a=ed25519; pk=pfvxvpFUDJV2h2nY0FidLUml22uGLSjByFbM6aqQQws= X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250204_040613_538260_F97158EA X-CRM114-Status: GOOD ( 20.79 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org Extend the generic vDSO data storage with a page for the random state data. The random state data is stored in a dedicated page, as the existing storage page is only meant for time-related, time-namespace-aware data. This simplifies to access logic to not need to handle time namespaces anymore and also frees up more space in the time-related page. In case further generic vDSO data store is required it can be added to the random state page. Signed-off-by: Thomas Weißschuh --- drivers/char/random.c | 6 +++--- include/asm-generic/vdso/vsyscall.h | 12 ++++++++++++ include/vdso/datapage.h | 10 ++++++++++ lib/vdso/datastore.c | 14 ++++++++++++++ lib/vdso/getrandom.c | 8 ++++++-- 5 files changed, 45 insertions(+), 5 deletions(-) diff --git a/drivers/char/random.c b/drivers/char/random.c index 2581186fa61b7b278916a27f99ee22b4851dc37a..92cbd24a36d8c73ac6a17e8e787eeae3f6af1922 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -278,7 +278,7 @@ static void crng_reseed(struct work_struct *work) WRITE_ONCE(base_crng.generation, next_gen); #ifdef CONFIG_VDSO_GETRANDOM /* base_crng.generation's invalid value is ULONG_MAX, while - * _vdso_rng_data.generation's invalid value is 0, so add one to the + * vdso_k_rng_data->generation's invalid value is 0, so add one to the * former to arrive at the latter. Use smp_store_release so that this * is ordered with the write above to base_crng.generation. Pairs with * the smp_rmb() before the syscall in the vDSO code. @@ -290,7 +290,7 @@ static void crng_reseed(struct work_struct *work) * because the vDSO side only checks whether the value changed, without * actually using or interpreting the value. */ - smp_store_release((unsigned long *)&__arch_get_k_vdso_rng_data()->generation, next_gen + 1); + smp_store_release((unsigned long *)&vdso_k_rng_data->generation, next_gen + 1); #endif if (!static_branch_likely(&crng_is_ready)) crng_init = CRNG_READY; @@ -743,7 +743,7 @@ static void __cold _credit_init_bits(size_t bits) queue_work(system_unbound_wq, &set_ready); atomic_notifier_call_chain(&random_ready_notifier, 0, NULL); #ifdef CONFIG_VDSO_GETRANDOM - WRITE_ONCE(__arch_get_k_vdso_rng_data()->is_ready, true); + WRITE_ONCE(vdso_k_rng_data->is_ready, true); #endif wake_up_interruptible(&crng_init_wait); kill_fasync(&fasync, SIGIO, POLL_IN); diff --git a/include/asm-generic/vdso/vsyscall.h b/include/asm-generic/vdso/vsyscall.h index ac5b93b91993224da245e80031b9f51e0c083f3c..a5f973e4e2723ef1815c88a7846f7c477e3febd9 100644 --- a/include/asm-generic/vdso/vsyscall.h +++ b/include/asm-generic/vdso/vsyscall.h @@ -13,6 +13,13 @@ static __always_inline const struct vdso_time_data *__arch_get_vdso_u_time_data( } #endif +#ifndef __arch_get_vdso_u_rng_data +static __always_inline const struct vdso_rng_data *__arch_get_vdso_u_rng_data(void) +{ + return &vdso_u_rng_data; +} +#endif + #else /* !CONFIG_GENERIC_VDSO_DATA_STORE */ #ifndef __arch_get_k_vdso_data @@ -25,6 +32,11 @@ static __always_inline struct vdso_data *__arch_get_k_vdso_data(void) #define __arch_get_vdso_u_time_data __arch_get_vdso_data +#ifndef __arch_get_vdso_u_rng_data +#define __arch_get_vdso_u_rng_data() __arch_get_vdso_rng_data() +#endif +#define vdso_k_rng_data __arch_get_k_vdso_rng_data() + #endif /* CONFIG_GENERIC_VDSO_DATA_STORE */ #ifndef __arch_update_vsyscall diff --git a/include/vdso/datapage.h b/include/vdso/datapage.h index b3d8087488ff35fbbc4d5058ae21e2c6cc58ed9c..7dbc8797e3b8923c06f4b6b34790766e68b2abd2 100644 --- a/include/vdso/datapage.h +++ b/include/vdso/datapage.h @@ -144,8 +144,10 @@ extern struct vdso_time_data _timens_data[CS_BASES] __attribute__((visibility("h extern struct vdso_rng_data _vdso_rng_data __attribute__((visibility("hidden"))); #else extern struct vdso_time_data vdso_u_time_data[CS_BASES] __attribute__((visibility("hidden"))); +extern struct vdso_rng_data vdso_u_rng_data __attribute__((visibility("hidden"))); extern struct vdso_time_data *vdso_k_time_data; +extern struct vdso_rng_data *vdso_k_rng_data; #endif /** @@ -161,6 +163,7 @@ union vdso_data_store { enum vdso_pages { VDSO_TIME_PAGE_OFFSET, VDSO_TIMENS_PAGE_OFFSET, + VDSO_RNG_PAGE_OFFSET, VDSO_NR_PAGES }; @@ -184,9 +187,16 @@ enum vdso_pages { #else /* !__ASSEMBLY__ */ +#ifdef CONFIG_VDSO_GETRANDOM +#define __vdso_u_rng_data PROVIDE(vdso_u_rng_data = vdso_u_data + 2 * PAGE_SIZE); +#else +#define __vdso_u_rng_data +#endif + #define VDSO_VVAR_SYMS \ PROVIDE(vdso_u_data = . - __VDSO_PAGES * PAGE_SIZE); \ PROVIDE(vdso_u_time_data = vdso_u_data); \ + __vdso_u_rng_data \ #endif /* !__ASSEMBLY__ */ diff --git a/lib/vdso/datastore.c b/lib/vdso/datastore.c index d3181768424cc3ee2e980bd537ac5ca14dfcb304..9260b00dc8520af109bd9dd05ac7f7504eafbea0 100644 --- a/lib/vdso/datastore.c +++ b/lib/vdso/datastore.c @@ -17,6 +17,15 @@ struct vdso_time_data *vdso_k_time_data = vdso_time_data_store.data; static_assert(sizeof(vdso_time_data_store) == PAGE_SIZE); #endif /* CONFIG_HAVE_GENERIC_VDSO */ +#ifdef CONFIG_VDSO_GETRANDOM +static union { + struct vdso_rng_data data; + u8 page[PAGE_SIZE]; +} vdso_rng_data_store __page_aligned_data; +struct vdso_rng_data *vdso_k_rng_data = &vdso_rng_data_store.data; +static_assert(sizeof(vdso_rng_data_store) == PAGE_SIZE); +#endif /* CONFIG_VDSO_GETRANDOM */ + static vm_fault_t vvar_fault(const struct vm_special_mapping *sm, struct vm_area_struct *vma, struct vm_fault *vmf) { @@ -53,6 +62,11 @@ static vm_fault_t vvar_fault(const struct vm_special_mapping *sm, return VM_FAULT_SIGBUS; pfn = __phys_to_pfn(__pa_symbol(vdso_k_time_data)); break; + case VDSO_RNG_PAGE_OFFSET: + if (!IS_ENABLED(CONFIG_VDSO_GETRANDOM)) + return VM_FAULT_SIGBUS; + pfn = __phys_to_pfn(__pa_symbol(vdso_k_rng_data)); + break; default: return VM_FAULT_SIGBUS; } diff --git a/lib/vdso/getrandom.c b/lib/vdso/getrandom.c index 938ca539aaa64bc46280ef6dd17aa661126699eb..440f8a6203a69a6462aafee4ad8d5670cef6a353 100644 --- a/lib/vdso/getrandom.c +++ b/lib/vdso/getrandom.c @@ -12,6 +12,9 @@ #include #include +/* Bring in default accessors */ +#include + #undef PAGE_SIZE #undef PAGE_MASK #define PAGE_SIZE (1UL << CONFIG_PAGE_SHIFT) @@ -152,7 +155,7 @@ __cvdso_getrandom_data(const struct vdso_rng_data *rng_info, void *buffer, size_ /* * Prevent the syscall from being reordered wrt current_generation. Pairs with the - * smp_store_release(&_vdso_rng_data.generation) in random.c. + * smp_store_release(&vdso_k_rng_data->generation) in random.c. */ smp_rmb(); @@ -256,5 +259,6 @@ __cvdso_getrandom_data(const struct vdso_rng_data *rng_info, void *buffer, size_ static __always_inline ssize_t __cvdso_getrandom(void *buffer, size_t len, unsigned int flags, void *opaque_state, size_t opaque_len) { - return __cvdso_getrandom_data(__arch_get_vdso_rng_data(), buffer, len, flags, opaque_state, opaque_len); + return __cvdso_getrandom_data(__arch_get_vdso_u_rng_data(), buffer, len, flags, + opaque_state, opaque_len); }