252 lines
6.6 KiB
C
252 lines
6.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* handle transition of Linux booting another kernel
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* Copyright (C) 2002-2005 Eric Biederman <ebiederm@xmission.com>
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*/
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#include <linux/mm.h>
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#include <linux/kexec.h>
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#include <linux/delay.h>
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#include <linux/numa.h>
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#include <linux/ftrace.h>
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#include <linux/suspend.h>
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#include <linux/gfp.h>
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#include <linux/io.h>
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#include <asm/pgalloc.h>
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#include <asm/tlbflush.h>
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#include <asm/mmu_context.h>
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#include <asm/apic.h>
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#include <asm/io_apic.h>
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#include <asm/cpufeature.h>
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#include <asm/desc.h>
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#include <asm/set_memory.h>
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#include <asm/debugreg.h>
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static void set_gdt(void *newgdt, __u16 limit)
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{
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struct desc_ptr curgdt;
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/* ia32 supports unaligned loads & stores */
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curgdt.size = limit;
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curgdt.address = (unsigned long)newgdt;
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load_gdt(&curgdt);
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}
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static void load_segments(void)
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{
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#define __STR(X) #X
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#define STR(X) __STR(X)
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__asm__ __volatile__ (
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"\tljmp $"STR(__KERNEL_CS)",$1f\n"
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"\t1:\n"
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"\tmovl $"STR(__KERNEL_DS)",%%eax\n"
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"\tmovl %%eax,%%ds\n"
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"\tmovl %%eax,%%es\n"
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"\tmovl %%eax,%%ss\n"
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: : : "eax", "memory");
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#undef STR
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#undef __STR
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}
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static void machine_kexec_free_page_tables(struct kimage *image)
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{
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free_pages((unsigned long)image->arch.pgd, PGD_ALLOCATION_ORDER);
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image->arch.pgd = NULL;
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#ifdef CONFIG_X86_PAE
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free_page((unsigned long)image->arch.pmd0);
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image->arch.pmd0 = NULL;
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free_page((unsigned long)image->arch.pmd1);
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image->arch.pmd1 = NULL;
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#endif
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free_page((unsigned long)image->arch.pte0);
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image->arch.pte0 = NULL;
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free_page((unsigned long)image->arch.pte1);
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image->arch.pte1 = NULL;
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}
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static int machine_kexec_alloc_page_tables(struct kimage *image)
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{
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image->arch.pgd = (pgd_t *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
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PGD_ALLOCATION_ORDER);
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#ifdef CONFIG_X86_PAE
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image->arch.pmd0 = (pmd_t *)get_zeroed_page(GFP_KERNEL);
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image->arch.pmd1 = (pmd_t *)get_zeroed_page(GFP_KERNEL);
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#endif
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image->arch.pte0 = (pte_t *)get_zeroed_page(GFP_KERNEL);
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image->arch.pte1 = (pte_t *)get_zeroed_page(GFP_KERNEL);
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if (!image->arch.pgd ||
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#ifdef CONFIG_X86_PAE
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!image->arch.pmd0 || !image->arch.pmd1 ||
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#endif
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!image->arch.pte0 || !image->arch.pte1) {
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return -ENOMEM;
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}
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return 0;
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}
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static void machine_kexec_page_table_set_one(
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pgd_t *pgd, pmd_t *pmd, pte_t *pte,
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unsigned long vaddr, unsigned long paddr)
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{
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p4d_t *p4d;
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pud_t *pud;
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pgd += pgd_index(vaddr);
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#ifdef CONFIG_X86_PAE
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if (!(pgd_val(*pgd) & _PAGE_PRESENT))
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set_pgd(pgd, __pgd(__pa(pmd) | _PAGE_PRESENT));
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#endif
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p4d = p4d_offset(pgd, vaddr);
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pud = pud_offset(p4d, vaddr);
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pmd = pmd_offset(pud, vaddr);
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if (!(pmd_val(*pmd) & _PAGE_PRESENT))
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set_pmd(pmd, __pmd(__pa(pte) | _PAGE_TABLE));
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pte = pte_offset_kernel(pmd, vaddr);
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set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC));
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}
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static void machine_kexec_prepare_page_tables(struct kimage *image)
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{
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void *control_page;
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pmd_t *pmd = NULL;
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control_page = page_address(image->control_code_page);
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#ifdef CONFIG_X86_PAE
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pmd = image->arch.pmd0;
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#endif
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machine_kexec_page_table_set_one(
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image->arch.pgd, pmd, image->arch.pte0,
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(unsigned long)control_page, __pa(control_page));
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#ifdef CONFIG_X86_PAE
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pmd = image->arch.pmd1;
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#endif
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machine_kexec_page_table_set_one(
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image->arch.pgd, pmd, image->arch.pte1,
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__pa(control_page), __pa(control_page));
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}
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/*
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* A architecture hook called to validate the
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* proposed image and prepare the control pages
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* as needed. The pages for KEXEC_CONTROL_PAGE_SIZE
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* have been allocated, but the segments have yet
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* been copied into the kernel.
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*
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* Do what every setup is needed on image and the
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* reboot code buffer to allow us to avoid allocations
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* later.
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*
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* - Make control page executable.
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* - Allocate page tables
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* - Setup page tables
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*/
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int machine_kexec_prepare(struct kimage *image)
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{
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int error;
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set_memory_x((unsigned long)page_address(image->control_code_page), 1);
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error = machine_kexec_alloc_page_tables(image);
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if (error)
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return error;
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machine_kexec_prepare_page_tables(image);
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return 0;
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}
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/*
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* Undo anything leftover by machine_kexec_prepare
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* when an image is freed.
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*/
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void machine_kexec_cleanup(struct kimage *image)
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{
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set_memory_nx((unsigned long)page_address(image->control_code_page), 1);
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machine_kexec_free_page_tables(image);
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}
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/*
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* Do not allocate memory (or fail in any way) in machine_kexec().
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* We are past the point of no return, committed to rebooting now.
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*/
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void machine_kexec(struct kimage *image)
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{
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unsigned long page_list[PAGES_NR];
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void *control_page;
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int save_ftrace_enabled;
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asmlinkage unsigned long
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(*relocate_kernel_ptr)(unsigned long indirection_page,
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unsigned long control_page,
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unsigned long start_address,
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unsigned int has_pae,
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unsigned int preserve_context);
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#ifdef CONFIG_KEXEC_JUMP
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if (image->preserve_context)
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save_processor_state();
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#endif
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save_ftrace_enabled = __ftrace_enabled_save();
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/* Interrupts aren't acceptable while we reboot */
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local_irq_disable();
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hw_breakpoint_disable();
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if (image->preserve_context) {
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#ifdef CONFIG_X86_IO_APIC
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/*
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* We need to put APICs in legacy mode so that we can
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* get timer interrupts in second kernel. kexec/kdump
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* paths already have calls to restore_boot_irq_mode()
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* in one form or other. kexec jump path also need one.
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*/
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clear_IO_APIC();
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restore_boot_irq_mode();
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#endif
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}
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control_page = page_address(image->control_code_page);
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memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE);
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relocate_kernel_ptr = control_page;
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page_list[PA_CONTROL_PAGE] = __pa(control_page);
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page_list[VA_CONTROL_PAGE] = (unsigned long)control_page;
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page_list[PA_PGD] = __pa(image->arch.pgd);
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if (image->type == KEXEC_TYPE_DEFAULT)
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page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page)
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<< PAGE_SHIFT);
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/*
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* The segment registers are funny things, they have both a
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* visible and an invisible part. Whenever the visible part is
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* set to a specific selector, the invisible part is loaded
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* with from a table in memory. At no other time is the
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* descriptor table in memory accessed.
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*
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* I take advantage of this here by force loading the
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* segments, before I zap the gdt with an invalid value.
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*/
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load_segments();
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/*
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* The gdt & idt are now invalid.
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* If you want to load them you must set up your own idt & gdt.
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*/
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idt_invalidate(phys_to_virt(0));
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set_gdt(phys_to_virt(0), 0);
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/* now call it */
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image->start = relocate_kernel_ptr((unsigned long)image->head,
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(unsigned long)page_list,
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image->start,
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boot_cpu_has(X86_FEATURE_PAE),
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image->preserve_context);
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#ifdef CONFIG_KEXEC_JUMP
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if (image->preserve_context)
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restore_processor_state();
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#endif
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__ftrace_enabled_restore(save_ftrace_enabled);
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}
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