From nobody Sun Feb 8 12:14:12 2026 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 01B451F9A86; Tue, 4 Mar 2025 08:27:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741076869; cv=none; b=qxqjJGztg2tuUX8O6pYRz6299NViHYsvO4GMaIWXKLK96owQ+QnT4bAKs+d9KQyWND24uiw4YyrI4jzMFBBD+sDUQeT88+26KDoARPr43ZSNm0/sI5iUEn+i/T7DLcbmS0WQzmWd39irKpQfwGnIewlrWX0UvYof9ROhmmgbtNE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741076869; c=relaxed/simple; bh=WWNzMmN3pyswpJtGDpWD7fa8PfeixzF5+7StlS3O8rU=; h=Date:From:To:Subject:Cc:In-Reply-To:References:MIME-Version: Message-ID:Content-Type; b=MTh4x7u9Um64xgMbryia8Vyzkv84R248MuPPKwIsYFwU8C6BQ1wkQ6ryEEBvqE5Ra9HUxeH2WFmFIQup7t0xe7skMYI5T8TPXAT54+h8AOoaMRmYTXXEF3JrBAYtABZm80mz95CrIEhRPd6JmvUShlafuhXVX0Obh+1wyBsy+d0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=Vwzv0ZXR; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=QU9xXN50; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="Vwzv0ZXR"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="QU9xXN50" Date: Tue, 04 Mar 2025 08:27:45 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1741076866; 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=UDvQc/bPVxRPP+UEs5VBMs08ObUgKjLiHTz7M23779E=; b=Vwzv0ZXR+OcYfK8zUUSpql5OvBAaY5EUXN5twMOgAAnhJo+BIhX3/0X6p6N5vJIi9MnHnh XEEMqmn6D2mm47NtZehnq0IvOkJqgsbNJD7V/raGmqQwovcKzT1ygdUDKut4cucGd42g1Y VTGBh8Rfq7T0hxipT0Bp06ejt0pmzCCYiu4gFKmxZrttUbAty+V381KOr5JnRxrbu9QV9o lQDdddAFFiyd5HY0tdLNY3j5T7N5Uaguw78bNQtc3Md/wJWIiU1x7ULUFsegBPFwULSUD1 eW9oLxODoi4doc5o+NSK5vm1w7c4ERfz4BavsrVI1BJH3JMPxK20veqvV0QJuQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1741076866; 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=UDvQc/bPVxRPP+UEs5VBMs08ObUgKjLiHTz7M23779E=; b=QU9xXN50xDCU2W43M3xzfAWi87F/1Ag5ijD1it9jRbohl6Wn4Qw2de3CMhCiSm6UIt89LM 37Y5/V96xp9J6/DA== From: "tip-bot2 for Brian Gerst" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/core] x86/percpu: Move current_task to percpu hot section Cc: Brian Gerst , Ingo Molnar , Uros Bizjak , Linus Torvalds , Peter Zijlstra , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20250303165246.2175811-10-brgerst@gmail.com> References: <20250303165246.2175811-10-brgerst@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-ID: <174107686576.14745.16411417754421340769.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Precedence: bulk Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable The following commit has been merged into the x86/core branch of tip: Commit-ID: bc91ad515dffab286194872e4bacfdb6faa18688 Gitweb: https://git.kernel.org/tip/bc91ad515dffab286194872e4bacfdb6f= aa18688 Author: Brian Gerst AuthorDate: Mon, 03 Mar 2025 11:52:44 -05:00 Committer: Ingo Molnar CommitterDate: Mon, 03 Mar 2025 21:37:41 +01:00 x86/percpu: Move current_task to percpu hot section No functional change. Signed-off-by: Brian Gerst Signed-off-by: Ingo Molnar Acked-by: Uros Bizjak Cc: Linus Torvalds Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20250303165246.2175811-10-brgerst@gmail.com --- arch/x86/include/asm/current.h | 17 ++++++----------- arch/x86/include/asm/percpu.h | 2 +- arch/x86/kernel/asm-offsets.c | 1 - arch/x86/kernel/cpu/common.c | 8 +++----- arch/x86/kernel/head_64.S | 4 ++-- arch/x86/kernel/process_32.c | 2 +- arch/x86/kernel/process_64.c | 2 +- arch/x86/kernel/smpboot.c | 2 +- arch/x86/kernel/vmlinux.lds.S | 2 +- scripts/gdb/linux/cpus.py | 2 +- 10 files changed, 17 insertions(+), 25 deletions(-) diff --git a/arch/x86/include/asm/current.h b/arch/x86/include/asm/current.h index 3d1b123..dea7d8b 100644 --- a/arch/x86/include/asm/current.h +++ b/arch/x86/include/asm/current.h @@ -12,22 +12,17 @@ =20 struct task_struct; =20 -struct pcpu_hot { - struct task_struct *current_task; -}; - -DECLARE_PER_CPU_CACHE_HOT(struct pcpu_hot, pcpu_hot); - -/* const-qualified alias to pcpu_hot, aliased by linker. */ -DECLARE_PER_CPU_CACHE_HOT(const struct pcpu_hot __percpu_seg_override, - const_pcpu_hot); +DECLARE_PER_CPU_CACHE_HOT(struct task_struct *, current_task); +/* const-qualified alias provided by the linker. */ +DECLARE_PER_CPU_CACHE_HOT(struct task_struct * const __percpu_seg_override, + const_current_task); =20 static __always_inline struct task_struct *get_current(void) { if (IS_ENABLED(CONFIG_USE_X86_SEG_SUPPORT)) - return this_cpu_read_const(const_pcpu_hot.current_task); + return this_cpu_read_const(const_current_task); =20 - return this_cpu_read_stable(pcpu_hot.current_task); + return this_cpu_read_stable(current_task); } =20 #define current get_current() diff --git a/arch/x86/include/asm/percpu.h b/arch/x86/include/asm/percpu.h index 1ca290b..6fbb52a 100644 --- a/arch/x86/include/asm/percpu.h +++ b/arch/x86/include/asm/percpu.h @@ -549,7 +549,7 @@ do { \ * it is accessed while this_cpu_read_stable() allows the value to be cach= ed. * this_cpu_read_stable() is more efficient and can be used if its value * is guaranteed to be valid across CPUs. The current users include - * pcpu_hot.current_task and cpu_current_top_of_stack, both of which are + * current_task and cpu_current_top_of_stack, both of which are * actually per-thread variables implemented as per-CPU variables and * thus stable for the duration of the respective task. */ diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c index 54ace80..ad4ea6f 100644 --- a/arch/x86/kernel/asm-offsets.c +++ b/arch/x86/kernel/asm-offsets.c @@ -107,7 +107,6 @@ static void __used common(void) OFFSET(TSS_sp0, tss_struct, x86_tss.sp0); OFFSET(TSS_sp1, tss_struct, x86_tss.sp1); OFFSET(TSS_sp2, tss_struct, x86_tss.sp2); - OFFSET(X86_current_task, pcpu_hot, current_task); #if IS_ENABLED(CONFIG_CRYPTO_ARIA_AESNI_AVX_X86_64) /* Offset for fields in aria_ctx */ BLANK(); diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 80fcc91..39782a2 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -2047,11 +2047,9 @@ static __init int setup_setcpuid(char *arg) } __setup("setcpuid=3D", setup_setcpuid); =20 -DEFINE_PER_CPU_CACHE_HOT(struct pcpu_hot, pcpu_hot) =3D { - .current_task =3D &init_task, -}; -EXPORT_PER_CPU_SYMBOL(pcpu_hot); -EXPORT_PER_CPU_SYMBOL(const_pcpu_hot); +DEFINE_PER_CPU_CACHE_HOT(struct task_struct *, current_task) =3D &init_tas= k; +EXPORT_PER_CPU_SYMBOL(current_task); +EXPORT_PER_CPU_SYMBOL(const_current_task); =20 DEFINE_PER_CPU_CACHE_HOT(int, __preempt_count) =3D INIT_PREEMPT_COUNT; EXPORT_PER_CPU_SYMBOL(__preempt_count); diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index 2843b0a..fefe2a2 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -322,7 +322,7 @@ SYM_INNER_LABEL(common_startup_64, SYM_L_LOCAL) * * RDX contains the per-cpu offset */ - movq pcpu_hot + X86_current_task(%rdx), %rax + movq current_task(%rdx), %rax movq TASK_threadsp(%rax), %rsp =20 /* @@ -433,7 +433,7 @@ SYM_CODE_START(soft_restart_cpu) UNWIND_HINT_END_OF_STACK =20 /* Find the idle task stack */ - movq PER_CPU_VAR(pcpu_hot + X86_current_task), %rcx + movq PER_CPU_VAR(current_task), %rcx movq TASK_threadsp(%rcx), %rsp =20 jmp .Ljump_to_C_code diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c index 8ec44ac..4636ef3 100644 --- a/arch/x86/kernel/process_32.c +++ b/arch/x86/kernel/process_32.c @@ -206,7 +206,7 @@ __switch_to(struct task_struct *prev_p, struct task_str= uct *next_p) if (prev->gs | next->gs) loadsegment(gs, next->gs); =20 - raw_cpu_write(pcpu_hot.current_task, next_p); + raw_cpu_write(current_task, next_p); =20 switch_fpu_finish(next_p); =20 diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index d8f4bce..7196ca7 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -668,7 +668,7 @@ __switch_to(struct task_struct *prev_p, struct task_str= uct *next_p) /* * Switch the PDA and FPU contexts. */ - raw_cpu_write(pcpu_hot.current_task, next_p); + raw_cpu_write(current_task, next_p); raw_cpu_write(cpu_current_top_of_stack, task_top_of_stack(next_p)); =20 switch_fpu_finish(next_p); diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 83ec0e9..95beca8 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -842,7 +842,7 @@ int common_cpu_up(unsigned int cpu, struct task_struct = *idle) /* Just in case we booted with a single CPU. */ alternatives_enable_smp(); =20 - per_cpu(pcpu_hot.current_task, cpu) =3D idle; + per_cpu(current_task, cpu) =3D idle; cpu_init_stack_canary(cpu, idle); =20 /* Initialize the interrupt stack(s) */ diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index 475f671..31f9102 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -43,7 +43,7 @@ ENTRY(phys_startup_64) #endif =20 jiffies =3D jiffies_64; -const_pcpu_hot =3D pcpu_hot; +const_current_task =3D current_task; const_cpu_current_top_of_stack =3D cpu_current_top_of_stack; =20 #if defined(CONFIG_X86_64) diff --git a/scripts/gdb/linux/cpus.py b/scripts/gdb/linux/cpus.py index 13eb8b3..8f7c4fb 100644 --- a/scripts/gdb/linux/cpus.py +++ b/scripts/gdb/linux/cpus.py @@ -164,7 +164,7 @@ def get_current_task(cpu): var_ptr =3D gdb.parse_and_eval("(struct task_struct *)cpu_task= s[0].task") return var_ptr.dereference() else: - var_ptr =3D gdb.parse_and_eval("&pcpu_hot.current_task") + var_ptr =3D gdb.parse_and_eval("¤t_task") return per_cpu(var_ptr, cpu).dereference() elif utils.is_target_arch("aarch64"): current_task_addr =3D gdb.parse_and_eval("(unsigned long)$SP_EL0")