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945fd17ab6
The separation of the cpu_entry_area from the fixmap missed the fact that
on 32bit non-PAE kernels the cpu_entry_area mapping might not be covered in
initial_page_table by the previous synchronizations.
This results in suspend/resume failures because 32bit utilizes initial page
table for resume. The absence of the cpu_entry_area mapping results in a
triple fault, aka. insta reboot.
With PAE enabled this works by chance because the PGD entry which covers
the fixmap and other parts incindentally provides the cpu_entry_area
mapping as well.
Synchronize the initial page table after setting up the cpu entry
area. Instead of adding yet another copy of the same code, move it to a
function and invoke it from the various places.
It needs to be investigated if the existing calls in setup_arch() and
setup_per_cpu_areas() can be replaced by the later invocation from
setup_cpu_entry_areas(), but that's beyond the scope of this fix.
Fixes: 92a0f81d89 ("x86/cpu_entry_area: Move it out of the fixmap")
Reported-by: Woody Suwalski <terraluna977@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Woody Suwalski <terraluna977@gmail.com>
Cc: William Grant <william.grant@canonical.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1802282137290.1392@nanos.tec.linutronix.de
302 lines
8.5 KiB
C
302 lines
8.5 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/bootmem.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 <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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#include <asm/stackprotector.h>
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DEFINE_PER_CPU_READ_MOSTLY(int, cpu_number);
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EXPORT_PER_CPU_SYMBOL(cpu_number);
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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_NEED_MULTIPLE_NODES
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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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/**
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* pcpu_alloc_bootmem - NUMA friendly alloc_bootmem wrapper for percpu
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* @cpu: cpu to allocate for
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* @size: size allocation in bytes
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* @align: alignment
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*
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* Allocate @size bytes aligned at @align for cpu @cpu. This wrapper
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* does the right thing for NUMA regardless of the current
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* configuration.
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*
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* RETURNS:
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* Pointer to the allocated area on success, NULL on failure.
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*/
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static void * __init pcpu_alloc_bootmem(unsigned int cpu, unsigned long size,
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unsigned long align)
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{
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const unsigned long goal = __pa(MAX_DMA_ADDRESS);
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#ifdef CONFIG_NEED_MULTIPLE_NODES
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int node = early_cpu_to_node(cpu);
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void *ptr;
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if (!node_online(node) || !NODE_DATA(node)) {
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ptr = __alloc_bootmem_nopanic(size, align, goal);
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pr_info("cpu %d has no node %d or node-local memory\n",
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cpu, node);
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pr_debug("per cpu data for cpu%d %lu bytes at %016lx\n",
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cpu, size, __pa(ptr));
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} else {
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ptr = __alloc_bootmem_node_nopanic(NODE_DATA(node),
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size, align, goal);
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pr_debug("per cpu data for cpu%d %lu bytes on node%d at %016lx\n",
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cpu, size, node, __pa(ptr));
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}
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return ptr;
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#else
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return __alloc_bootmem_nopanic(size, align, goal);
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#endif
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}
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/*
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* Helpers for first chunk memory allocation
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*/
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static void * __init pcpu_fc_alloc(unsigned int cpu, size_t size, size_t align)
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{
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return pcpu_alloc_bootmem(cpu, size, align);
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}
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static void __init pcpu_fc_free(void *ptr, size_t size)
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{
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free_bootmem(__pa(ptr), size);
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}
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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_NEED_MULTIPLE_NODES
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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 void __init pcpup_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(0x8092, per_cpu_offset(cpu),
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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:%d\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_fc_alloc, pcpu_fc_free);
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if (rc < 0)
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pr_warning("%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_fc_alloc, pcpu_fc_free,
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pcpup_populate_pte);
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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(cpu_number, cpu) = cpu;
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setup_percpu_segment(cpu);
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setup_stack_canary_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_bios_cpu_apicid, cpu) =
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early_per_cpu_map(x86_bios_cpu_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_X86_32
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per_cpu(x86_cpu_to_logical_apicid, cpu) =
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early_per_cpu_map(x86_cpu_to_logical_apicid, cpu);
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#endif
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#ifdef CONFIG_X86_64
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per_cpu(irq_stack_ptr, cpu) =
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per_cpu(irq_stack_union.irq_stack, cpu) +
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IRQ_STACK_SIZE;
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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_to_new_gdt(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_bios_cpu_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_X86_32
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early_per_cpu_ptr(x86_cpu_to_logical_apicid) = 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. We can't reliably pick up percpu mappings
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* using vmalloc_fault(), because exception dispatch needs
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* percpu data.
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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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