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From: "Chang S. Bae" <chang.seok.bae@intel.com>
To: Ingo Molnar <mingo@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Andy Lutomirski <luto@kernel.org>,
	"H . Peter Anvin" <hpa@zytor.com>
Cc: Andi Kleen <ak@linux.intel.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Markus T Metzger <markus.t.metzger@intel.com>,
	Ravi Shankar <ravi.v.shankar@intel.com>,
	"Chang S . Bae" <chang.seok.bae@intel.com>,
	LKML <linux-kernel@vger.kernel.org>
Subject: [PATCH v6 8/8] x86/vdso: Move out the CPU initialization
Date: Tue, 18 Sep 2018 16:08:59 -0700	[thread overview]
Message-ID: <1537312139-5580-9-git-send-email-chang.seok.bae@intel.com> (raw)
In-Reply-To: <1537312139-5580-1-git-send-email-chang.seok.bae@intel.com>

The CPU and node number will be written, as early enough,
to the segment limit of per CPU data and TSC_AUX MSR entry.
The information has been retrieved by vgetcpu in user space
and will be also loaded from the paranoid entry, when
FSGSBASE enabled.

The new setup function is named after the getcpu(2) system
call, and will be called during each CPU initialization
(before setting up IST). It makes a facility useful to both
the kernel and userspace unconditionally available much
sooner.

The change brings a substantial code removal. The redundant
setting of the segment in entry/vdso/vma.c and hotplug
notifier are removed.

Suggested-by: H. Peter Anvin <hpa@zytor.com>
Suggested-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
---
 arch/x86/entry/vdso/vma.c    | 33 +--------------------------------
 arch/x86/kernel/cpu/common.c | 24 ++++++++++++++++++++++++
 2 files changed, 25 insertions(+), 32 deletions(-)

diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index 39b5584..3f9d43f 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -332,35 +332,6 @@ static __init int vdso_setup(char *s)
 	return 0;
 }
 __setup("vdso=", vdso_setup);
-#endif
-
-#ifdef CONFIG_X86_64
-static void vgetcpu_cpu_init(void *arg)
-{
-	int cpu = smp_processor_id();
-	struct desc_struct d = { };
-	unsigned long cpudata = vdso_encode_cpu_node(cpu, cpu_to_node(cpu));
-
-	if (static_cpu_has(X86_FEATURE_RDTSCP))
-		write_rdtscp_aux(cpudata);
-
-	/* Store CPU and node number in limit */
-	d.limit0 = cpudata;
-	d.limit1 = cpudata >> 16;
-
-	d.type = 5;		/* RO data, expand down, accessed */
-	d.dpl = 3;		/* Visible to user code */
-	d.s = 1;		/* Not a system segment */
-	d.p = 1;		/* Present */
-	d.d = 1;		/* 32-bit */
-
-	write_gdt_entry(get_cpu_gdt_rw(cpu), GDT_ENTRY_CPU_NUMBER, &d, DESCTYPE_S);
-}
-
-static int vgetcpu_online(unsigned int cpu)
-{
-	return smp_call_function_single(cpu, vgetcpu_cpu_init, NULL, 1);
-}
 
 static int __init init_vdso(void)
 {
@@ -370,9 +341,7 @@ static int __init init_vdso(void)
 	init_vdso_image(&vdso_image_x32);
 #endif
 
-	/* notifier priority > KVM */
-	return cpuhp_setup_state(CPUHP_AP_X86_VDSO_VMA_ONLINE,
-				 "x86/vdso/vma:online", vgetcpu_online, NULL);
+	return 0;
 }
 subsys_initcall(init_vdso);
 #endif /* CONFIG_X86_64 */
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 1ac7e6e..359a422 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1660,6 +1660,29 @@ static void wait_for_master_cpu(int cpu)
 #endif
 }
 
+#ifdef CONFIG_X86_64
+static void setup_getcpu(int cpu)
+{
+	unsigned long cpudata = vdso_encode_cpu_node(cpu, early_cpu_to_node(cpu));
+	struct desc_struct d = { };
+
+	if (static_cpu_has(X86_FEATURE_RDTSCP))
+		write_rdtscp_aux(cpudata);
+
+	/* Store CPU and node number in limit. */
+	d.limit0 = cpudata;
+	d.limit1 = cpudata >> 16;
+
+	d.type = 5;		/* RO data, expand down, accessed */
+	d.dpl = 3;		/* Visible to user code */
+	d.s = 1;		/* Not a system segment */
+	d.p = 1;		/* Present */
+	d.d = 1;		/* 32-bit */
+
+	write_gdt_entry(get_cpu_gdt_rw(cpu), GDT_ENTRY_CPU_NUMBER, &d, DESCTYPE_S);
+}
+#endif
+
 /*
  * cpu_init() initializes state that is per-CPU. Some data is already
  * initialized (naturally) in the bootstrap process, such as the GDT
@@ -1697,6 +1720,7 @@ void cpu_init(void)
 	    early_cpu_to_node(cpu) != NUMA_NO_NODE)
 		set_numa_node(early_cpu_to_node(cpu));
 #endif
+	setup_getcpu(cpu);
 
 	me = current;
 
-- 
2.7.4


  parent reply	other threads:[~2018-09-18 23:09 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-18 23:08 [PATCH v6 0/8] x86: infrastructure to enable FSGSBASE Chang S. Bae
2018-09-18 23:08 ` [PATCH v6 1/8] x86/arch_prctl/64: Make ptrace read FS/GS base accurately Chang S. Bae
2018-10-08  9:54   ` [tip:x86/asm] x86/fsgsbase/64: Fix ptrace() to read the " tip-bot for Andy Lutomirski
2018-10-08  9:59   ` [tip:x86/asm] x86/segments: Introduce the 'CPUNODE' naming to better document the segment limit CPU/node NR trick tip-bot for Ingo Molnar
2018-10-08  9:59   ` [tip:x86/asm] x86/fsgsbase/64: Clean up various details tip-bot for Ingo Molnar
2018-09-18 23:08 ` [PATCH v6 2/8] x86/fsgsbase/64: Introduce FS/GS base helper functions Chang S. Bae
2018-10-08  9:55   ` [tip:x86/asm] " tip-bot for Chang S. Bae
2018-10-24 19:01   ` [regression in -rc1] Re: [PATCH v6 2/8] " Andy Lutomirski
2018-10-24 19:13     ` Bae, Chang Seok
2018-10-24 19:22       ` Andy Lutomirski
2018-10-24 19:29         ` Bae, Chang Seok
2018-10-24 19:43           ` Andy Lutomirski
2018-10-24 22:50             ` Bae, Chang Seok
2018-10-25 22:37     ` Andy Lutomirski
2018-09-18 23:08 ` [PATCH v6 3/8] x86/fsgsbase/64: Make ptrace use correct FS/GS base helpers Chang S. Bae
2018-10-08  9:56   ` [tip:x86/asm] x86/fsgsbase/64: Make ptrace use the new " tip-bot for Chang S. Bae
2018-09-18 23:08 ` [PATCH v6 4/8] x86/fsgsbase/64: Use FS/GS base helpers in core dump Chang S. Bae
2018-10-08  9:56   ` [tip:x86/asm] x86/fsgsbase/64: Convert the ELF core dump code to the new FSGSBASE helpers tip-bot for Chang S. Bae
2018-09-18 23:08 ` [PATCH v6 5/8] x86/fsgsbase/64: Factor out load FS/GS segments from __switch_to() Chang S. Bae
2018-10-08  9:57   ` [tip:x86/asm] x86/fsgsbase/64: Factor out FS/GS segment loading " tip-bot for Chang S. Bae
2018-09-18 23:08 ` [PATCH v6 6/8] x86/segments/64: Rename PER_CPU segment to CPU_NUMBER Chang S. Bae
2018-10-08  9:57   ` [tip:x86/asm] x86/segments/64: Rename the GDT PER_CPU entry " tip-bot for Chang S. Bae
2018-09-18 23:08 ` [PATCH v6 7/8] x86/vdso: Introduce helper functions for CPU and node number Chang S. Bae
2018-10-08  9:58   ` [tip:x86/asm] " tip-bot for Chang S. Bae
2018-09-18 23:08 ` Chang S. Bae [this message]
2018-10-08  8:36   ` [PATCH v6 8/8] x86/vdso: Move out the CPU initialization Ingo Molnar
2018-10-08  9:58   ` [tip:x86/asm] x86/vdso: Initialize the CPU/node NR segment descriptor earlier tip-bot for Chang S. Bae

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