![Andi Kleen](/assets/img/avatar_default.png)
Instead of hackish manual parsing Requires earlier i386 patchkit, but also fixes i386 early_printk again. I removed some obsolete really early parameters which didn't do anything useful. Also made a few parameters that needed it early (mostly oops printing setup) Also removed one panic check that wasn't visible without early console anyways (the early console is now initialized after that panic) This cleans up a lot of code. Signed-off-by: Andi Kleen <ak@suse.de>
257 lines
6.3 KiB
C
257 lines
6.3 KiB
C
/*
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* machine_kexec.c - 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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* This source code is licensed under the GNU General Public License,
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* Version 2. See the file COPYING for more details.
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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/string.h>
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#include <linux/reboot.h>
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#include <asm/pgtable.h>
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#include <asm/tlbflush.h>
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#include <asm/mmu_context.h>
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#include <asm/io.h>
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static void init_level2_page(pmd_t *level2p, unsigned long addr)
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{
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unsigned long end_addr;
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addr &= PAGE_MASK;
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end_addr = addr + PUD_SIZE;
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while (addr < end_addr) {
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set_pmd(level2p++, __pmd(addr | __PAGE_KERNEL_LARGE_EXEC));
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addr += PMD_SIZE;
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}
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}
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static int init_level3_page(struct kimage *image, pud_t *level3p,
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unsigned long addr, unsigned long last_addr)
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{
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unsigned long end_addr;
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int result;
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result = 0;
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addr &= PAGE_MASK;
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end_addr = addr + PGDIR_SIZE;
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while ((addr < last_addr) && (addr < end_addr)) {
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struct page *page;
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pmd_t *level2p;
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page = kimage_alloc_control_pages(image, 0);
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if (!page) {
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result = -ENOMEM;
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goto out;
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}
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level2p = (pmd_t *)page_address(page);
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init_level2_page(level2p, addr);
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set_pud(level3p++, __pud(__pa(level2p) | _KERNPG_TABLE));
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addr += PUD_SIZE;
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}
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/* clear the unused entries */
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while (addr < end_addr) {
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pud_clear(level3p++);
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addr += PUD_SIZE;
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}
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out:
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return result;
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}
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static int init_level4_page(struct kimage *image, pgd_t *level4p,
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unsigned long addr, unsigned long last_addr)
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{
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unsigned long end_addr;
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int result;
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result = 0;
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addr &= PAGE_MASK;
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end_addr = addr + (PTRS_PER_PGD * PGDIR_SIZE);
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while ((addr < last_addr) && (addr < end_addr)) {
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struct page *page;
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pud_t *level3p;
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page = kimage_alloc_control_pages(image, 0);
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if (!page) {
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result = -ENOMEM;
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goto out;
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}
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level3p = (pud_t *)page_address(page);
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result = init_level3_page(image, level3p, addr, last_addr);
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if (result) {
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goto out;
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}
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set_pgd(level4p++, __pgd(__pa(level3p) | _KERNPG_TABLE));
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addr += PGDIR_SIZE;
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}
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/* clear the unused entries */
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while (addr < end_addr) {
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pgd_clear(level4p++);
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addr += PGDIR_SIZE;
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}
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out:
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return result;
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}
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static int init_pgtable(struct kimage *image, unsigned long start_pgtable)
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{
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pgd_t *level4p;
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level4p = (pgd_t *)__va(start_pgtable);
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return init_level4_page(image, level4p, 0, end_pfn << PAGE_SHIFT);
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}
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static void set_idt(void *newidt, u16 limit)
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{
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struct desc_ptr curidt;
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/* x86-64 supports unaliged loads & stores */
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curidt.size = limit;
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curidt.address = (unsigned long)newidt;
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__asm__ __volatile__ (
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"lidtq %0\n"
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: : "m" (curidt)
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);
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};
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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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/* x86-64 supports unaligned loads & stores */
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curgdt.size = limit;
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curgdt.address = (unsigned long)newgdt;
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__asm__ __volatile__ (
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"lgdtq %0\n"
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: : "m" (curgdt)
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);
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};
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static void load_segments(void)
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{
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__asm__ __volatile__ (
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"\tmovl %0,%%ds\n"
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"\tmovl %0,%%es\n"
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"\tmovl %0,%%ss\n"
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"\tmovl %0,%%fs\n"
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"\tmovl %0,%%gs\n"
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: : "a" (__KERNEL_DS) : "memory"
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);
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}
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typedef NORET_TYPE void (*relocate_new_kernel_t)(unsigned long indirection_page,
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unsigned long control_code_buffer,
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unsigned long start_address,
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unsigned long pgtable) ATTRIB_NORET;
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extern const unsigned char relocate_new_kernel[];
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extern const unsigned long relocate_new_kernel_size;
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int machine_kexec_prepare(struct kimage *image)
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{
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unsigned long start_pgtable, control_code_buffer;
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int result;
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/* Calculate the offsets */
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start_pgtable = page_to_pfn(image->control_code_page) << PAGE_SHIFT;
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control_code_buffer = start_pgtable + PAGE_SIZE;
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/* Setup the identity mapped 64bit page table */
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result = init_pgtable(image, start_pgtable);
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if (result)
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return result;
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/* Place the code in the reboot code buffer */
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memcpy(__va(control_code_buffer), relocate_new_kernel,
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relocate_new_kernel_size);
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return 0;
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}
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void machine_kexec_cleanup(struct kimage *image)
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{
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return;
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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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NORET_TYPE void machine_kexec(struct kimage *image)
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{
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unsigned long page_list;
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unsigned long control_code_buffer;
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unsigned long start_pgtable;
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relocate_new_kernel_t rnk;
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/* Interrupts aren't acceptable while we reboot */
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local_irq_disable();
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/* Calculate the offsets */
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page_list = image->head;
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start_pgtable = page_to_pfn(image->control_code_page) << PAGE_SHIFT;
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control_code_buffer = start_pgtable + PAGE_SIZE;
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/* Set the low half of the page table to my identity mapped
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* page table for kexec. Leave the high half pointing at the
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* kernel pages. Don't bother to flush the global pages
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* as that will happen when I fully switch to my identity mapped
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* page table anyway.
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*/
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memcpy(__va(read_cr3()), __va(start_pgtable), PAGE_SIZE/2);
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__flush_tlb();
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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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/* 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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set_gdt(phys_to_virt(0),0);
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set_idt(phys_to_virt(0),0);
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/* now call it */
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rnk = (relocate_new_kernel_t) control_code_buffer;
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(*rnk)(page_list, control_code_buffer, image->start, start_pgtable);
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}
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/* crashkernel=size@addr specifies the location to reserve for
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* a crash kernel. By reserving this memory we guarantee
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* that linux never set's it up as a DMA target.
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* Useful for holding code to do something appropriate
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* after a kernel panic.
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*/
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static int __init setup_crashkernel(char *arg)
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{
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unsigned long size, base;
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char *p;
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if (!arg)
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return -EINVAL;
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size = memparse(arg, &p);
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if (arg == p)
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return -EINVAL;
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if (*p == '@') {
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base = memparse(p+1, &p);
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/* FIXME: Do I want a sanity check to validate the
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* memory range? Yes you do, but it's too early for
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* e820 -AK */
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crashk_res.start = base;
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crashk_res.end = base + size - 1;
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}
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return 0;
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}
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early_param("crashkernel", setup_crashkernel);
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