/*
* 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/reboot.h>
#include <linux/numa.h>
#include <linux/ftrace.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
#include <asm/mmu_context.h>
#include <asm/io.h>
static void init_level2_page(pmd_t *level2p, unsigned long addr)
{
unsigned long end_addr;
addr &= PAGE_MASK;
end_addr = addr + PUD_SIZE;
while (addr < end_addr) {
set_pmd(level2p++, __pmd(addr | __PAGE_KERNEL_LARGE_EXEC));
addr += PMD_SIZE;
}
}
static int init_level3_page(struct kimage *image, pud_t *level3p,
unsigned long addr, unsigned long last_addr)
{
unsigned long end_addr;
int result;
result = 0;
addr &= PAGE_MASK;
end_addr = addr + PGDIR_SIZE;
while ((addr < last_addr) && (addr < end_addr)) {
struct page *page;
pmd_t *level2p;
page = kimage_alloc_control_pages(image, 0);
if (!page) {
result = -ENOMEM;
goto out;
}
level2p = (pmd_t *)page_address(page);
init_level2_page(level2p, addr);
set_pud(level3p++, __pud(__pa(level2p) | _KERNPG_TABLE));
addr += PUD_SIZE;
}
/* clear the unused entries */
while (addr < end_addr) {
pud_clear(level3p++);
addr += PUD_SIZE;
}
out:
return result;
}
static int init_level4_page(struct kimage *image, pgd_t *level4p,
unsigned long addr, unsigned long last_addr)
{
unsigned long end_addr;
int result;
result = 0;
addr &= PAGE_MASK;
end_addr = addr + (PTRS_PER_PGD * PGDIR_SIZE);
while ((addr < last_addr) && (addr < end_addr)) {
struct page *page;
pud_t *level3p;
page = kimage_alloc_control_pages(image, 0);
if (!page) {
result = -ENOMEM;
goto out;
}
level3p = (pud_t *)page_address(page);
result = init_level3_page(image, level3p, addr, last_addr);
if (result) {
goto out;
}
set_pgd(level4p++, __pgd(__pa(level3p) | _KERNPG_TABLE));
addr += PGDIR_SIZE;
}
/* clear the unused entries */
while (addr < end_addr) {
pgd_clear(level4p++);
addr += PGDIR_SIZE;
}
out:
return result;
}
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 int init_pgtable(struct kimage *image, unsigned long start_pgtable)
{
pgd_t *level4p;
int result;
level4p = (pgd_t *)__va(start_pgtable);
result = init_level4_page(image, level4p, 0, max_pfn << PAGE_SHIFT);
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;
tracer_disable();
/* Interrupts aren't acceptable while we reboot */
local_irq_disable();
control_page = page_address(image->control_code_page) + PAGE_SIZE;
memcpy(control_page, relocate_kernel, PAGE_SIZE);
page_list[PA_CONTROL_PAGE] = virt_to_phys(control_page);
page_list[PA_TABLE_PAGE] =
(unsigned long)__pa(page_address(image->control_code_page));
/* 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 */
relocate_kernel((unsigned long)image->head, (unsigned long)page_list,
image->start);
}
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
}
