diff options
Diffstat (limited to 'arch/x86/kernel/machine_kexec_32.c')
| -rw-r--r-- | arch/x86/kernel/machine_kexec_32.c | 171 |
1 files changed, 171 insertions, 0 deletions
diff --git a/arch/x86/kernel/machine_kexec_32.c b/arch/x86/kernel/machine_kexec_32.c new file mode 100644 index 000000000000..91966bafb3dc --- /dev/null +++ b/arch/x86/kernel/machine_kexec_32.c @@ -0,0 +1,171 @@ +/* + * machine_kexec.c - 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/delay.h> +#include <linux/init.h> +#include <asm/pgtable.h> +#include <asm/pgalloc.h> +#include <asm/tlbflush.h> +#include <asm/mmu_context.h> +#include <asm/io.h> +#include <asm/apic.h> +#include <asm/cpufeature.h> +#include <asm/desc.h> +#include <asm/system.h> + +#define PAGE_ALIGNED __attribute__ ((__aligned__(PAGE_SIZE))) +static u32 kexec_pgd[1024] PAGE_ALIGNED; +#ifdef CONFIG_X86_PAE +static u32 kexec_pmd0[1024] PAGE_ALIGNED; +static u32 kexec_pmd1[1024] PAGE_ALIGNED; +#endif +static u32 kexec_pte0[1024] PAGE_ALIGNED; +static u32 kexec_pte1[1024] PAGE_ALIGNED; + +static void set_idt(void *newidt, __u16 limit) +{ + struct Xgt_desc_struct curidt; + + /* ia32 supports unaliged loads & stores */ + curidt.size = limit; + curidt.address = (unsigned long)newidt; + + load_idt(&curidt); +}; + + +static void set_gdt(void *newgdt, __u16 limit) +{ + struct Xgt_desc_struct curgdt; + + /* ia32 supports unaligned loads & stores */ + curgdt.size = limit; + curgdt.address = (unsigned long)newgdt; + + load_gdt(&curgdt); +}; + +static void load_segments(void) +{ +#define __STR(X) #X +#define STR(X) __STR(X) + + __asm__ __volatile__ ( + "\tljmp $"STR(__KERNEL_CS)",$1f\n" + "\t1:\n" + "\tmovl $"STR(__KERNEL_DS)",%%eax\n" + "\tmovl %%eax,%%ds\n" + "\tmovl %%eax,%%es\n" + "\tmovl %%eax,%%fs\n" + "\tmovl %%eax,%%gs\n" + "\tmovl %%eax,%%ss\n" + ::: "eax", "memory"); +#undef STR +#undef __STR +} + +/* + * A architecture hook called to validate the + * proposed image and prepare the control pages + * as needed. The pages for KEXEC_CONTROL_CODE_SIZE + * have been allocated, but the segments have yet + * been copied into the kernel. + * + * Do what every setup is needed on image and the + * reboot code buffer to allow us to avoid allocations + * later. + * + * Currently nothing. + */ +int machine_kexec_prepare(struct kimage *image) +{ + return 0; +} + +/* + * Undo anything leftover by machine_kexec_prepare + * when an image is freed. + */ +void machine_kexec_cleanup(struct kimage *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. + */ +NORET_TYPE void machine_kexec(struct kimage *image) +{ + unsigned long page_list[PAGES_NR]; + void *control_page; + + /* Interrupts aren't acceptable while we reboot */ + local_irq_disable(); + + control_page = page_address(image->control_code_page); + memcpy(control_page, relocate_kernel, PAGE_SIZE); + + page_list[PA_CONTROL_PAGE] = __pa(control_page); + page_list[VA_CONTROL_PAGE] = (unsigned long)relocate_kernel; + page_list[PA_PGD] = __pa(kexec_pgd); + page_list[VA_PGD] = (unsigned long)kexec_pgd; +#ifdef CONFIG_X86_PAE + page_list[PA_PMD_0] = __pa(kexec_pmd0); + page_list[VA_PMD_0] = (unsigned long)kexec_pmd0; + page_list[PA_PMD_1] = __pa(kexec_pmd1); + page_list[VA_PMD_1] = (unsigned long)kexec_pmd1; +#endif + page_list[PA_PTE_0] = __pa(kexec_pte0); + page_list[VA_PTE_0] = (unsigned long)kexec_pte0; + page_list[PA_PTE_1] = __pa(kexec_pte1); + page_list[VA_PTE_1] = (unsigned long)kexec_pte1; + + /* 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, cpu_has_pae); +} + +/* crashkernel=size@addr specifies the location to reserve for + * a crash kernel. By reserving this memory we guarantee + * that linux never sets it up as a DMA target. + * Useful for holding code to do something appropriate + * after a kernel panic. + */ +static int __init parse_crashkernel(char *arg) +{ + unsigned long size, base; + size = memparse(arg, &arg); + if (*arg == '@') { + base = memparse(arg+1, &arg); + /* FIXME: Do I want a sanity check + * to validate the memory range? + */ + crashk_res.start = base; + crashk_res.end = base + size - 1; + } + return 0; +} +early_param("crashkernel", parse_crashkernel); |