bc90aefa99
The D/B size flag for the 32-bit percpu GDT entry was not set.
The Intel manual (vol 3, section 3.4.5) only specifies the meaning of
this flag for three cases:
1) code segments used for %cs -- doesn't apply here
2) stack segments used for %ss -- doesn't apply
3) expand-down data segments -- but we don't have the expand-down flag
set, so it also doesn't apply here
The flag likely doesn't do anything here, although the manual does also
say: "This flag should always be set to 1 for 32-bit code and data
segments [...]" so we should probably do it anyway.
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20231219151200.2878271-6-vegard.nossum@oracle.com
235 lines
6.5 KiB
C
235 lines
6.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/kernel.h>
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#include <linux/export.h>
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#include <linux/init.h>
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#include <linux/memblock.h>
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#include <linux/percpu.h>
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#include <linux/kexec.h>
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#include <linux/crash_dump.h>
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#include <linux/smp.h>
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#include <linux/topology.h>
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#include <linux/pfn.h>
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#include <linux/stackprotector.h>
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#include <asm/sections.h>
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#include <asm/processor.h>
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#include <asm/desc.h>
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#include <asm/setup.h>
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#include <asm/mpspec.h>
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#include <asm/apicdef.h>
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#include <asm/highmem.h>
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#include <asm/proto.h>
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#include <asm/cpumask.h>
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#include <asm/cpu.h>
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#ifdef CONFIG_X86_64
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#define BOOT_PERCPU_OFFSET ((unsigned long)__per_cpu_load)
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#else
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#define BOOT_PERCPU_OFFSET 0
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#endif
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DEFINE_PER_CPU_READ_MOSTLY(unsigned long, this_cpu_off) = BOOT_PERCPU_OFFSET;
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EXPORT_PER_CPU_SYMBOL(this_cpu_off);
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unsigned long __per_cpu_offset[NR_CPUS] __ro_after_init = {
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[0 ... NR_CPUS-1] = BOOT_PERCPU_OFFSET,
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};
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EXPORT_SYMBOL(__per_cpu_offset);
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/*
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* On x86_64 symbols referenced from code should be reachable using
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* 32bit relocations. Reserve space for static percpu variables in
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* modules so that they are always served from the first chunk which
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* is located at the percpu segment base. On x86_32, anything can
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* address anywhere. No need to reserve space in the first chunk.
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*/
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#ifdef CONFIG_X86_64
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#define PERCPU_FIRST_CHUNK_RESERVE PERCPU_MODULE_RESERVE
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#else
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#define PERCPU_FIRST_CHUNK_RESERVE 0
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#endif
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#ifdef CONFIG_X86_32
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/**
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* pcpu_need_numa - determine percpu allocation needs to consider NUMA
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*
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* If NUMA is not configured or there is only one NUMA node available,
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* there is no reason to consider NUMA. This function determines
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* whether percpu allocation should consider NUMA or not.
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*
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* RETURNS:
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* true if NUMA should be considered; otherwise, false.
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*/
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static bool __init pcpu_need_numa(void)
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{
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#ifdef CONFIG_NUMA
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pg_data_t *last = NULL;
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unsigned int cpu;
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for_each_possible_cpu(cpu) {
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int node = early_cpu_to_node(cpu);
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if (node_online(node) && NODE_DATA(node) &&
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last && last != NODE_DATA(node))
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return true;
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last = NODE_DATA(node);
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}
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#endif
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return false;
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}
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#endif
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static int __init pcpu_cpu_distance(unsigned int from, unsigned int to)
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{
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#ifdef CONFIG_NUMA
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if (early_cpu_to_node(from) == early_cpu_to_node(to))
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return LOCAL_DISTANCE;
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else
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return REMOTE_DISTANCE;
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#else
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return LOCAL_DISTANCE;
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#endif
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}
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static int __init pcpu_cpu_to_node(int cpu)
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{
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return early_cpu_to_node(cpu);
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}
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void __init pcpu_populate_pte(unsigned long addr)
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{
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populate_extra_pte(addr);
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}
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static inline void setup_percpu_segment(int cpu)
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{
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#ifdef CONFIG_X86_32
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struct desc_struct d = GDT_ENTRY_INIT(DESC_DATA32,
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per_cpu_offset(cpu), 0xFFFFF);
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write_gdt_entry(get_cpu_gdt_rw(cpu), GDT_ENTRY_PERCPU, &d, DESCTYPE_S);
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#endif
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}
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void __init setup_per_cpu_areas(void)
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{
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unsigned int cpu;
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unsigned long delta;
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int rc;
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pr_info("NR_CPUS:%d nr_cpumask_bits:%d nr_cpu_ids:%u nr_node_ids:%u\n",
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NR_CPUS, nr_cpumask_bits, nr_cpu_ids, nr_node_ids);
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/*
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* Allocate percpu area. Embedding allocator is our favorite;
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* however, on NUMA configurations, it can result in very
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* sparse unit mapping and vmalloc area isn't spacious enough
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* on 32bit. Use page in that case.
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*/
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#ifdef CONFIG_X86_32
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if (pcpu_chosen_fc == PCPU_FC_AUTO && pcpu_need_numa())
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pcpu_chosen_fc = PCPU_FC_PAGE;
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#endif
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rc = -EINVAL;
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if (pcpu_chosen_fc != PCPU_FC_PAGE) {
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const size_t dyn_size = PERCPU_MODULE_RESERVE +
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PERCPU_DYNAMIC_RESERVE - PERCPU_FIRST_CHUNK_RESERVE;
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size_t atom_size;
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/*
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* On 64bit, use PMD_SIZE for atom_size so that embedded
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* percpu areas are aligned to PMD. This, in the future,
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* can also allow using PMD mappings in vmalloc area. Use
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* PAGE_SIZE on 32bit as vmalloc space is highly contended
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* and large vmalloc area allocs can easily fail.
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*/
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#ifdef CONFIG_X86_64
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atom_size = PMD_SIZE;
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#else
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atom_size = PAGE_SIZE;
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#endif
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rc = pcpu_embed_first_chunk(PERCPU_FIRST_CHUNK_RESERVE,
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dyn_size, atom_size,
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pcpu_cpu_distance,
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pcpu_cpu_to_node);
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if (rc < 0)
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pr_warn("%s allocator failed (%d), falling back to page size\n",
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pcpu_fc_names[pcpu_chosen_fc], rc);
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}
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if (rc < 0)
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rc = pcpu_page_first_chunk(PERCPU_FIRST_CHUNK_RESERVE,
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pcpu_cpu_to_node);
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if (rc < 0)
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panic("cannot initialize percpu area (err=%d)", rc);
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/* alrighty, percpu areas up and running */
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delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
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for_each_possible_cpu(cpu) {
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per_cpu_offset(cpu) = delta + pcpu_unit_offsets[cpu];
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per_cpu(this_cpu_off, cpu) = per_cpu_offset(cpu);
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per_cpu(pcpu_hot.cpu_number, cpu) = cpu;
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setup_percpu_segment(cpu);
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/*
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* Copy data used in early init routines from the
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* initial arrays to the per cpu data areas. These
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* arrays then become expendable and the *_early_ptr's
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* are zeroed indicating that the static arrays are
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* gone.
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*/
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#ifdef CONFIG_X86_LOCAL_APIC
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per_cpu(x86_cpu_to_apicid, cpu) =
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early_per_cpu_map(x86_cpu_to_apicid, cpu);
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per_cpu(x86_cpu_to_acpiid, cpu) =
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early_per_cpu_map(x86_cpu_to_acpiid, cpu);
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#endif
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#ifdef CONFIG_NUMA
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per_cpu(x86_cpu_to_node_map, cpu) =
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early_per_cpu_map(x86_cpu_to_node_map, cpu);
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/*
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* Ensure that the boot cpu numa_node is correct when the boot
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* cpu is on a node that doesn't have memory installed.
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* Also cpu_up() will call cpu_to_node() for APs when
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* MEMORY_HOTPLUG is defined, before per_cpu(numa_node) is set
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* up later with c_init aka intel_init/amd_init.
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* So set them all (boot cpu and all APs).
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*/
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set_cpu_numa_node(cpu, early_cpu_to_node(cpu));
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#endif
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/*
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* Up to this point, the boot CPU has been using .init.data
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* area. Reload any changed state for the boot CPU.
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*/
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if (!cpu)
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switch_gdt_and_percpu_base(cpu);
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}
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/* indicate the early static arrays will soon be gone */
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#ifdef CONFIG_X86_LOCAL_APIC
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early_per_cpu_ptr(x86_cpu_to_apicid) = NULL;
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early_per_cpu_ptr(x86_cpu_to_acpiid) = NULL;
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#endif
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#ifdef CONFIG_NUMA
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early_per_cpu_ptr(x86_cpu_to_node_map) = NULL;
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#endif
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/* Setup node to cpumask map */
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setup_node_to_cpumask_map();
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/* Setup cpu initialized, callin, callout masks */
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setup_cpu_local_masks();
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/*
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* Sync back kernel address range again. We already did this in
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* setup_arch(), but percpu data also needs to be available in
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* the smpboot asm and arch_sync_kernel_mappings() doesn't sync to
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* swapper_pg_dir on 32-bit. The per-cpu mappings need to be available
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* there too.
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*
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* FIXME: Can the later sync in setup_cpu_entry_areas() replace
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* this call?
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*/
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sync_initial_page_table();
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}
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