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* handle transition of Linux booting another kernel
* Copyright (C) 2002-2005 Eric Biederman <ebiederm@xmission.com>
*
* This source code is licensed under the GNU General Public License,
* Version 2. See the file COPYING for more details.
*/
#include <linux/mm.h>
#include <linux/kexec.h>
#include <linux/string.h>
#include <linux/gfp.h>
#include <linux/reboot.h>
#include <linux/numa.h>
#include <linux/ftrace.h>
#include <linux/io.h>
#include <linux/suspend.h>
#include <asm/init.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
#include <asm/mmu_context.h>
#include <asm/debugreg.h>
static void free_transition_pgtable(struct kimage *image)
{
free_page((unsigned long)image->arch.pud);
free_page((unsigned long)image->arch.pmd);
free_page((unsigned long)image->arch.pte);
}
static int init_transition_pgtable(struct kimage *image, pgd_t *pgd)
{
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
unsigned long vaddr, paddr;
int result = -ENOMEM;
vaddr = (unsigned long)relocate_kernel;
paddr = __pa(page_address(image->control_code_page)+PAGE_SIZE);
pgd += pgd_index(vaddr);
if (!pgd_present(*pgd)) {
pud = (pud_t *)get_zeroed_page(GFP_KERNEL);
if (!pud)
goto err;
image->arch.pud = pud;
set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE));
}
pud = pud_offset(pgd, vaddr);
if (!pud_present(*pud)) {
pmd = (pmd_t *)get_zeroed_page(GFP_KERNEL);
if (!pmd)
goto err;
image->arch.pmd = pmd;
set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
}
pmd = pmd_offset(pud, vaddr);
if (!pmd_present(*pmd)) {
pte = (pte_t *)get_zeroed_page(GFP_KERNEL);
if (!pte)
goto err;
image->arch.pte = pte;
set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE));
}
pte = pte_offset_kernel(pmd, vaddr);
set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC));
return 0;
err:
free_transition_pgtable(image);
return result;
}
static void *alloc_pgt_page(void *data)
{
struct kimage *image = (struct kimage *)data;
struct page *page;
void *p = NULL;
page = kimage_alloc_control_pages(image, 0);
if (page) {
p = page_address(page);
clear_page(p);
}
return p;
}
static int init_pgtable(struct kimage *image, unsigned long start_pgtable)
{
struct x86_mapping_info info = {
.alloc_pgt_page = alloc_pgt_page,
.context = image,
.pmd_flag = __PAGE_KERNEL_LARGE_EXEC,
};
unsigned long mstart, mend;
pgd_t *level4p;
int result;
int i;
level4p = (pgd_t *)__va(start_pgtable);
clear_page(level4p);
for (i = 0; i < nr_pfn_mapped; i++) {
mstart = pfn_mapped[i].start << PAGE_SHIFT;
mend = pfn_mapped[i].end << PAGE_SHIFT;
result = kernel_ident_mapping_init(&info,
level4p, mstart, mend);
if (result)
return result;
}
/*
* segments's mem ranges could be outside 0 ~ max_pfn,
* for example when jump back to original kernel from kexeced kernel.
* or first kernel is booted with user mem map, and second kernel
* could be loaded out of that range.
*/
for (i = 0; i < image->nr_segments; i++) {
mstart = image->segment[i].mem;
mend = mstart + image->segment[i].memsz;
result = kernel_ident_mapping_init(&info,
level4p, mstart, mend);
if (result)
return result;
}
return init_transition_pgtable(image, level4p);
}
static void set_idt(void *newidt, u16 limit)
{
struct desc_ptr curidt;
/* x86-64 supports unaliged loads & stores */
curidt.size = limit;
curidt.address = (unsigned long)newidt;
__asm__ __volatile__ (
"lidtq %0\n"
: : "m" (curidt)
);
};
static void set_gdt(void *newgdt, u16 limit)
{
struct desc_ptr curgdt;
/* x86-64 supports unaligned loads & stores */
curgdt.size = limit;
curgdt.address = (unsigned long)newgdt;
__asm__ __volatile__ (
"lgdtq %0\n"
: : "m" (curgdt)
);
};
static void load_segments(void)
{
__asm__ __volatile__ (
"\tmovl %0,%%ds\n"
"\tmovl %0,%%es\n"
"\tmovl %0,%%ss\n"
"\tmovl %0,%%fs\n"
"\tmovl %0,%%gs\n"
: : "a" (__KERNEL_DS) : "memory"
);
}
int machine_kexec_prepare(struct kimage *image)
{
unsigned long start_pgtable;
int result;
/* Calculate the offsets */
start_pgtable = page_to_pfn(image->control_code_page) << PAGE_SHIFT;
/* Setup the identity mapped 64bit page table */
result = init_pgtable(image, start_pgtable);
if (result)
return result;
return 0;
}
void machine_kexec_cleanup(struct kimage *image)
{
free_transition_pgtable(image);
}
/*
* Do not allocate memory (or fail in any way) in machine_kexec().
* We are past the point of no return, committed to rebooting now.
*/
void machine_kexec(struct kimage *image)
{
unsigned long page_list[PAGES_NR];
void *control_page;
int save_ftrace_enabled;
#ifdef CONFIG_KEXEC_JUMP
if (image->preserve_context)
save_processor_state();
#endif
save_ftrace_enabled = __ftrace_enabled_save();
/* Interrupts aren't acceptable while we reboot */
local_irq_disable();
hw_breakpoint_disable();
if (image->preserve_context) {
#ifdef CONFIG_X86_IO_APIC
/*
* We need to put APICs in legacy mode so that we can
* get timer interrupts in second kernel. kexec/kdump
* paths already have calls to disable_IO_APIC() in
* one form or other. kexec jump path also need
* one.
*/
disable_IO_APIC();
#endif
}
control_page = page_address(image->control_code_page) + PAGE_SIZE;
memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE);
page_list[PA_CONTROL_PAGE] = virt_to_phys(control_page);
page_list[VA_CONTROL_PAGE] = (unsigned long)control_page;
page_list[PA_TABLE_PAGE] =
(unsigned long)__pa(page_address(image->control_code_page));
if (image->type == KEXEC_TYPE_DEFAULT)
page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page)
<< PAGE_SHIFT);
/*
* The segment registers are funny things, they have both a
* visible and an invisible part. Whenever the visible part is
* set to a specific selector, the invisible part is loaded
* with from a table in memory. At no other time is the
* descriptor table in memory accessed.
*
* I take advantage of this here by force loading the
* segments, before I zap the gdt with an invalid value.
*/
load_segments();
/*
* The gdt & idt are now invalid.
* If you want to load them you must set up your own idt & gdt.
*/
set_gdt(phys_to_virt(0), 0);
set_idt(phys_to_virt(0), 0);
/* now call it */
image->start = relocate_kernel((unsigned long)image->head,
(unsigned long)page_list,
image->start,
image->preserve_context);
#ifdef CONFIG_KEXEC_JUMP
if (image->preserve_context)
restore_processor_state();
#endif
__ftrace_enabled_restore(save_ftrace_enabled);
}
void arch_crash_save_vmcoreinfo(void)
{
VMCOREINFO_SYMBOL(phys_base);
VMCOREINFO_SYMBOL(init_level4_pgt);
#ifdef CONFIG_NUMA
VMCOREINFO_SYMBOL(node_data);
VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
#endif
}
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