From nobody Sat Sep 13 01:48:49 2025 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CA173C05027 for ; Mon, 6 Feb 2023 14:57:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231171AbjBFO55 (ORCPT ); Mon, 6 Feb 2023 09:57:57 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41056 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230101AbjBFO5t (ORCPT ); Mon, 6 Feb 2023 09:57:49 -0500 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AF0DB30E9; Mon, 6 Feb 2023 06:57:47 -0800 (PST) Date: Mon, 06 Feb 2023 14:57:46 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1675695466; h=from:from:sender:sender:reply-to: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=btbN0AE/UGdyFWTJPvRWHlPDrIrpiFlhuBh5UGVrx1M=; b=u8WcgwveZlDlKTB3PcAF2v8Of5TluA/5O2okM/udiJdqGcn3zBrt4lE8VErBZlnttYp3cy Zp94ttwdU5BSpN5dLorBjvDpgwDTO0kZhSdthcVcYi6VfCIxv38vUOn66M1tPrwELRaxUV ALnh+7/7PeRixhwIR79L3rv9rMyHjlRkER1r19cd8cLDdozjmKLoh1ESQ2gNSziAGQwTad 1v6OtcqOf69vVc0u7alP2Dtnab9322ulbpuWmTcNgGr0BN5IMmPjwz/ntbXnWFXwpb3UeW yocTEFGKjOKbhQnrQfBsJ2I5nUo36jo89vZ8ADrO7VCPK0gv7cyV/MTrCRNFcA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1675695466; h=from:from:sender:sender:reply-to: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=btbN0AE/UGdyFWTJPvRWHlPDrIrpiFlhuBh5UGVrx1M=; b=YthzoUKr3G3xki8S9TZwIoJ2oP0ChNzjwit+Y3+AbIY/gqiTRAFh9BkbY/xIMqWFhea0Ac haHRXFnb6mpOoLDw== From: "tip-bot2 for Sebastian Andrzej Siewior" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/vdso] x86/cpu: Provide the full setup for getcpu() on x86-32 Cc: Sebastian Andrzej Siewior , Thomas Gleixner , Roland Mainz , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20221125094216.3663444-2-bigeasy@linutronix.de> References: <20221125094216.3663444-2-bigeasy@linutronix.de> MIME-Version: 1.0 Message-ID: <167569546601.4906.5987162401774591165.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the x86/vdso branch of tip: Commit-ID: 717cce3bdcf34705417f641bf2fcdf9b038ec36c Gitweb: https://git.kernel.org/tip/717cce3bdcf34705417f641bf2fcdf9b0= 38ec36c Author: Sebastian Andrzej Siewior AuthorDate: Fri, 25 Nov 2022 10:42:14 +01:00 Committer: Thomas Gleixner CommitterDate: Mon, 06 Feb 2023 15:48:54 +01:00 x86/cpu: Provide the full setup for getcpu() on x86-32 setup_getcpu() configures two things: - it writes the current CPU & node information into MSR_TSC_AUX - it writes the same information as a GDT entry. By using the "full" setup_getcpu() on i386 it is possible to read the CPU information in userland via RDTSCP() or via LSL from the GDT. Provide an GDT_ENTRY_CPUNODE for x86-32 and make the setup function unconditionally available. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner Reviewed-by: Roland Mainz Link: https://lore.kernel.org/r/20221125094216.3663444-2-bigeasy@linutronix= .de --- arch/x86/include/asm/segment.h | 8 ++++---- arch/x86/kernel/cpu/common.c | 4 +--- 2 files changed, 5 insertions(+), 7 deletions(-) diff --git a/arch/x86/include/asm/segment.h b/arch/x86/include/asm/segment.h index c390a67..794f696 100644 --- a/arch/x86/include/asm/segment.h +++ b/arch/x86/include/asm/segment.h @@ -96,7 +96,7 @@ * * 26 - ESPFIX small SS * 27 - per-cpu [ offset to per-cpu data area ] - * 28 - unused + * 28 - VDSO getcpu * 29 - unused * 30 - unused * 31 - TSS for double fault handler @@ -119,6 +119,7 @@ =20 #define GDT_ENTRY_ESPFIX_SS 26 #define GDT_ENTRY_PERCPU 27 +#define GDT_ENTRY_CPUNODE 28 =20 #define GDT_ENTRY_DOUBLEFAULT_TSS 31 =20 @@ -159,6 +160,8 @@ # define __KERNEL_PERCPU 0 #endif =20 +#define __CPUNODE_SEG (GDT_ENTRY_CPUNODE*8 + 3) + #else /* 64-bit: */ =20 #include @@ -226,8 +229,6 @@ #define GDT_ENTRY_TLS_ENTRIES 3 #define TLS_SIZE (GDT_ENTRY_TLS_ENTRIES* 8) =20 -#ifdef CONFIG_X86_64 - /* Bit size and mask of CPU number stored in the per CPU data (and TSC_AUX= ) */ #define VDSO_CPUNODE_BITS 12 #define VDSO_CPUNODE_MASK 0xfff @@ -265,7 +266,6 @@ static inline void vdso_read_cpunode(unsigned *cpu, uns= igned *node) } =20 #endif /* !__ASSEMBLY__ */ -#endif /* CONFIG_X86_64 */ =20 #ifdef __KERNEL__ =20 diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 3a9043e..a26ce20 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -2124,7 +2124,6 @@ static void wait_for_master_cpu(int cpu) #endif } =20 -#ifdef CONFIG_X86_64 static inline void setup_getcpu(int cpu) { unsigned long cpudata =3D vdso_encode_cpunode(cpu, early_cpu_to_node(cpu)= ); @@ -2146,6 +2145,7 @@ static inline void setup_getcpu(int cpu) write_gdt_entry(get_cpu_gdt_rw(cpu), GDT_ENTRY_CPUNODE, &d, DESCTYPE_S); } =20 +#ifdef CONFIG_X86_64 static inline void ucode_cpu_init(int cpu) { if (cpu) @@ -2165,8 +2165,6 @@ static inline void tss_setup_ist(struct tss_struct *t= ss) =20 #else /* CONFIG_X86_64 */ =20 -static inline void setup_getcpu(int cpu) { } - static inline void ucode_cpu_init(int cpu) { show_ucode_info_early();