From: "Chang S. Bae" <chang.seok.bae@intel.com>
Date: Tue, 18 Sep 2018 16:08:59 -0700
Subject: x86/vdso: Initialize the CPU/node NR segment descriptor earlier
Git-commit: b2e2ba578e016a091eb31565849990fe68c7c599
Patch-mainline: v4.20-rc1
References: fate#325585
Currently the CPU/node NR segment descriptor (GDT_ENTRY_CPU_NUMBER) is
initialized relatively late during CPU init, from the vCPU code, which
has a number of disadvantages, such as hotplug CPU notifiers and SMP
cross-calls.
Instead just initialize it much earlier, directly in cpu_init().
This reduces complexity and increases robustness.
[ mingo: Wrote new changelog. ]
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: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Markus T Metzger <markus.t.metzger@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Shankar <ravi.v.shankar@intel.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1537312139-5580-9-git-send-email-chang.seok.bae@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Borislav Petkov <bp@suse.de>
---
arch/x86/entry/vdso/vma.c | 33 +--------------------------------
arch/x86/kernel/cpu/common.c | 24 ++++++++++++++++++++++++
2 files changed, 25 insertions(+), 32 deletions(-)
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -335,35 +335,6 @@ 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.limit = 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)
{
@@ -373,9 +344,7 @@ 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 */
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1623,6 +1623,29 @@ 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.limit = 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
@@ -1660,6 +1683,7 @@ 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;