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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 06/11] x86/xen: Add i386 kexec/kdump implementation
On Thu, Sep 27, 2012 at 08:06:33PM +0200, Daniel Kiper wrote: > Add i386 kexec/kdump implementation. > > Signed-off-by: Daniel Kiper <daniel.kiper@xxxxxxxxxx> > --- > arch/x86/xen/machine_kexec_32.c | 245 ++++++++++++++++++++++++++++ > arch/x86/xen/relocate_kernel_32.S | 323 > +++++++++++++++++++++++++++++++++++++ > 2 files changed, 568 insertions(+), 0 deletions(-) > create mode 100644 arch/x86/xen/machine_kexec_32.c > create mode 100644 arch/x86/xen/relocate_kernel_32.S > > diff --git a/arch/x86/xen/machine_kexec_32.c b/arch/x86/xen/machine_kexec_32.c > new file mode 100644 > index 0000000..6b5141e > --- /dev/null > +++ b/arch/x86/xen/machine_kexec_32.c > @@ -0,0 +1,245 @@ > +/* > + * Copyright (c) 2011 Daniel Kiper > + * Copyright (c) 2012 Daniel Kiper, Oracle Corporation > + * > + * kexec/kdump implementation for Xen was written by Daniel Kiper. > + * Initial work on it was sponsored by Google under Google Summer > + * of Code 2011 program and Citrix. Konrad Rzeszutek Wilk from Oracle > + * was the mentor for this project. > + * > + * Some ideas are taken from: > + * - native kexec/kdump implementation, > + * - kexec/kdump implementation for Xen Linux Kernel Ver. 2.6.18, > + * - PV-GRUB. > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License as published by > + * the Free Software Foundation; either version 2 of the License, or > + * (at your option) any later version. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + * > + * You should have received a copy of the GNU General Public License along > + * with this program. If not, see <http://www.gnu.org/licenses/>. > + */ > + > +#include <linux/errno.h> > +#include <linux/init.h> > +#include <linux/kernel.h> > +#include <linux/kexec.h> > +#include <linux/mm.h> > +#include <linux/string.h> > + > +#include <xen/xen.h> > +#include <xen/xen-ops.h> > + > +#include <asm/xen/hypercall.h> > +#include <asm/xen/kexec.h> > +#include <asm/xen/page.h> > + > +#define __ma(vaddr) (virt_to_machine(vaddr).maddr) > + > +static struct page *kimage_alloc_pages(gfp_t gfp_mask, > + unsigned int order, > + unsigned long limit) > +{ > + struct page *pages; > + unsigned int address_bits, i; > + > + pages = alloc_pages(gfp_mask, order); > + > + if (!pages) > + return NULL; > + > + address_bits = (limit == ULONG_MAX) ? BITS_PER_LONG : ilog2(limit); > + > + /* Relocate set of pages below given limit. */ > + if (xen_create_contiguous_region((unsigned long)page_address(pages), > + order, address_bits)) { > + __free_pages(pages, order); > + return NULL; > + } > + > + pages->mapping = NULL; It shouldn't matter (as you did the alloc_page) but could you add: BUG_ON(PagePrivate(pages)) in case somebody did do something weird beforehand. > + set_page_private(pages, order); > + > + for (i = 0; i < (1 << order); ++i) > + SetPageReserved(pages + i); > + > + return pages; > +} > + > +static void kimage_free_pages(struct page *page) > +{ > + unsigned int i, order; > + > + order = page_private(page); > + > + for (i = 0; i < (1 << order); ++i) > + ClearPageReserved(page + i); > + > + xen_destroy_contiguous_region((unsigned long)page_address(page), order); > + __free_pages(page, order); > +} > + > +static unsigned long xen_page_to_mfn(struct page *page) > +{ > + return pfn_to_mfn(page_to_pfn(page)); > +} > + > +static struct page *xen_mfn_to_page(unsigned long mfn) > +{ > + return pfn_to_page(mfn_to_pfn(mfn)); > +} > + > +static unsigned long xen_virt_to_machine(volatile void *address) > +{ > + return virt_to_machine(address).maddr; > +} > + > +static void *xen_machine_to_virt(unsigned long address) > +{ > + return phys_to_virt(machine_to_phys(XMADDR(address)).paddr); > +} > + > +static void free_transition_pgtable(struct kimage *image) > +{ > + free_page((unsigned long)image->arch.pgd); > + free_page((unsigned long)image->arch.pmd0); > + free_page((unsigned long)image->arch.pmd1); > + free_page((unsigned long)image->arch.pte0); > + free_page((unsigned long)image->arch.pte1); > +} > + > +static int alloc_transition_pgtable(struct kimage *image) > +{ > + image->arch.pgd = (pgd_t *)get_zeroed_page(GFP_KERNEL); > + > + if (!image->arch.pgd) > + goto err; > + > + image->arch.pmd0 = (pmd_t *)get_zeroed_page(GFP_KERNEL); > + > + if (!image->arch.pmd0) > + goto err; > + > + image->arch.pmd1 = (pmd_t *)get_zeroed_page(GFP_KERNEL); > + > + if (!image->arch.pmd1) > + goto err; > + > + image->arch.pte0 = (pte_t *)get_zeroed_page(GFP_KERNEL); > + > + if (!image->arch.pte0) > + goto err; > + > + image->arch.pte1 = (pte_t *)get_zeroed_page(GFP_KERNEL); > + > + if (!image->arch.pte1) > + goto err; > + > + return 0; > + > +err: > + free_transition_pgtable(image); > + > + return -ENOMEM; > +} > + > +static int machine_xen_kexec_prepare(struct kimage *image) > +{ > +#ifdef CONFIG_KEXEC_JUMP > + if (image->preserve_context) { > + pr_info_once("kexec: Context preservation is not " > + "supported in Xen domains.\n"); > + return -ENOSYS; > + } > +#endif > + > + return alloc_transition_pgtable(image); > +} > + > +static int machine_xen_kexec_load(struct kimage *image) > +{ > + void *control_page; > + struct xen_kexec_load xkl = {}; > + > + if (!image) > + return 0; Not -EINVAL? > + > + control_page = page_address(image->control_code_page); > + memcpy(control_page, xen_relocate_kernel, xen_kexec_control_code_size); > + > + xkl.type = image->type; > + xkl.image.page_list[XK_MA_CONTROL_PAGE] = __ma(control_page); > + xkl.image.page_list[XK_MA_TABLE_PAGE] = 0; /* Unused. */ > + xkl.image.page_list[XK_MA_PGD_PAGE] = __ma(image->arch.pgd); > + xkl.image.page_list[XK_MA_PUD0_PAGE] = 0; /* Unused. */ > + xkl.image.page_list[XK_MA_PUD1_PAGE] = 0; /* Unused. */ > + xkl.image.page_list[XK_MA_PMD0_PAGE] = __ma(image->arch.pmd0); > + xkl.image.page_list[XK_MA_PMD1_PAGE] = __ma(image->arch.pmd1); > + xkl.image.page_list[XK_MA_PTE0_PAGE] = __ma(image->arch.pte0); > + xkl.image.page_list[XK_MA_PTE1_PAGE] = __ma(image->arch.pte1); > + xkl.image.indirection_page = image->head; > + xkl.image.start_address = image->start; > + > + return HYPERVISOR_kexec_op(KEXEC_CMD_kexec_load, &xkl); > +} > + > +static void machine_xen_kexec_cleanup(struct kimage *image) > +{ > + free_transition_pgtable(image); > +} > + > +static void machine_xen_kexec_unload(struct kimage *image) > +{ > + int rc; > + struct xen_kexec_load xkl = {}; > + > + if (!image) > + return; > + > + xkl.type = image->type; > + rc = HYPERVISOR_kexec_op(KEXEC_CMD_kexec_unload, &xkl); > + > + WARN(rc, "kexec: %s: HYPERVISOR_kexec_op(): %i\n", __func__, rc); > +} > + > +static void machine_xen_kexec_shutdown(void) > +{ > +} > + > +static void machine_xen_kexec(struct kimage *image) > +{ > + int rc; > + struct xen_kexec_exec xke = {}; > + > + xke.type = image->type; > + rc = HYPERVISOR_kexec_op(KEXEC_CMD_kexec, &xke); > + > + pr_emerg("kexec: %s: HYPERVISOR_kexec_op(): %i\n", __func__, rc); > + BUG(); > +} > + > +void __init xen_init_kexec_ops(void) > +{ > + if (!xen_initial_domain()) > + return; > + > + kexec_ops.always_use_normal_alloc = true; > + kexec_ops.kimage_alloc_pages = kimage_alloc_pages; > + kexec_ops.kimage_free_pages = kimage_free_pages; > + kexec_ops.page_to_pfn = xen_page_to_mfn; > + kexec_ops.pfn_to_page = xen_mfn_to_page; > + kexec_ops.virt_to_phys = xen_virt_to_machine; > + kexec_ops.phys_to_virt = xen_machine_to_virt; > + kexec_ops.machine_kexec_prepare = machine_xen_kexec_prepare; > + kexec_ops.machine_kexec_load = machine_xen_kexec_load; > + kexec_ops.machine_kexec_cleanup = machine_xen_kexec_cleanup; > + kexec_ops.machine_kexec_unload = machine_xen_kexec_unload; > + kexec_ops.machine_kexec_shutdown = machine_xen_kexec_shutdown; > + kexec_ops.machine_kexec = machine_xen_kexec; > +} > diff --git a/arch/x86/xen/relocate_kernel_32.S > b/arch/x86/xen/relocate_kernel_32.S > new file mode 100644 > index 0000000..0e81830 > --- /dev/null > +++ b/arch/x86/xen/relocate_kernel_32.S > @@ -0,0 +1,323 @@ > +/* > + * Copyright (c) 2002-2005 Eric Biederman <ebiederm@xxxxxxxxxxxx> > + * Copyright (c) 2011 Daniel Kiper > + * Copyright (c) 2012 Daniel Kiper, Oracle Corporation > + * > + * kexec/kdump implementation for Xen was written by Daniel Kiper. > + * Initial work on it was sponsored by Google under Google Summer > + * of Code 2011 program and Citrix. Konrad Rzeszutek Wilk from Oracle > + * was the mentor for this project. > + * > + * Some ideas are taken from: > + * - native kexec/kdump implementation, > + * - kexec/kdump implementation for Xen Linux Kernel Ver. 2.6.18, > + * - PV-GRUB. > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License as published by > + * the Free Software Foundation; either veesion 2 of the License, or > + * (at your option) any later veesion. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + * > + * You should have received a copy of the GNU General Public License along > + * with this program. If not, see <http://www.gnu.org/licenses/>. > + */ > + > +#include <asm/cache.h> > +#include <asm/page_types.h> > +#include <asm/pgtable_types.h> > +#include <asm/processor-flags.h> > + > +#include <asm/xen/kexec.h> > + > +#define ARG_INDIRECTION_PAGE 0x4 > +#define ARG_PAGE_LIST 0x8 > +#define ARG_START_ADDRESS 0xc > + > +#define PTR(x) (x << 2) > + > + .text > + .align PAGE_SIZE > + .globl xen_kexec_control_code_size, xen_relocate_kernel > + > +xen_relocate_kernel: > + /* > + * Must be relocatable PIC code callable as a C function. > + * > + * This function is called by Xen but here hypervisor is dead. > + * We are playing on bare metal. > + * > + * Every machine address passed to this function through > + * page_list (e.g. XK_MA_CONTROL_PAGE) is established > + * by dom0 during kexec load phase. > + * > + * Every virtual address passed to this function through page_list > + * (e.g. XK_VA_CONTROL_PAGE) is established by hypervisor during > + * HYPERVISOR_kexec_op(KEXEC_CMD_kexec_load) hypercall. > + * > + * 0x4(%esp) - indirection_page, > + * 0x8(%esp) - page_list, > + * 0xc(%esp) - start_address, > + * 0x10(%esp) - cpu_has_pae (ignored), > + * 0x14(%esp) - preserve_context (ignored). > + */ > + > + /* Zero out flags, and disable interrupts. */ > + pushl $0 > + popfl > + > + /* Get page_list address. */ > + movl ARG_PAGE_LIST(%esp), %esi > + > + /* > + * Map the control page at its virtual address > + * in transition page table. > + */ > + movl PTR(XK_VA_CONTROL_PAGE)(%esi), %eax > + > + /* Get PGD address and PGD entry index. */ > + movl PTR(XK_VA_PGD_PAGE)(%esi), %ebx > + movl %eax, %ecx > + shrl $PGDIR_SHIFT, %ecx > + andl $(PTRS_PER_PGD - 1), %ecx > + > + /* Fill PGD entry with PMD0 reference. */ > + movl PTR(XK_MA_PMD0_PAGE)(%esi), %edx > + orl $_PAGE_PRESENT, %edx > + movl %edx, (%ebx, %ecx, 8) > + > + /* Get PMD0 address and PMD0 entry index. */ > + movl PTR(XK_VA_PMD0_PAGE)(%esi), %ebx > + movl %eax, %ecx > + shrl $PMD_SHIFT, %ecx > + andl $(PTRS_PER_PMD - 1), %ecx > + > + /* Fill PMD0 entry with PTE0 reference. */ > + movl PTR(XK_MA_PTE0_PAGE)(%esi), %edx > + orl $_KERNPG_TABLE, %edx > + movl %edx, (%ebx, %ecx, 8) > + > + /* Get PTE0 address and PTE0 entry index. */ > + movl PTR(XK_VA_PTE0_PAGE)(%esi), %ebx > + movl %eax, %ecx > + shrl $PAGE_SHIFT, %ecx > + andl $(PTRS_PER_PTE - 1), %ecx > + > + /* Fill PTE0 entry with control page reference. */ > + movl PTR(XK_MA_CONTROL_PAGE)(%esi), %edx > + orl $__PAGE_KERNEL_EXEC, %edx > + movl %edx, (%ebx, %ecx, 8) > + > + /* > + * Identity map the control page at its machine address > + * in transition page table. > + */ > + movl PTR(XK_MA_CONTROL_PAGE)(%esi), %eax > + > + /* Get PGD address and PGD entry index. */ > + movl PTR(XK_VA_PGD_PAGE)(%esi), %ebx > + movl %eax, %ecx > + shrl $PGDIR_SHIFT, %ecx > + andl $(PTRS_PER_PGD - 1), %ecx > + > + /* Fill PGD entry with PMD1 reference. */ > + movl PTR(XK_MA_PMD1_PAGE)(%esi), %edx > + orl $_PAGE_PRESENT, %edx > + movl %edx, (%ebx, %ecx, 8) > + > + /* Get PMD1 address and PMD1 entry index. */ > + movl PTR(XK_VA_PMD1_PAGE)(%esi), %ebx > + movl %eax, %ecx > + shrl $PMD_SHIFT, %ecx > + andl $(PTRS_PER_PMD - 1), %ecx > + > + /* Fill PMD1 entry with PTE1 reference. */ > + movl PTR(XK_MA_PTE1_PAGE)(%esi), %edx > + orl $_KERNPG_TABLE, %edx > + movl %edx, (%ebx, %ecx, 8) > + > + /* Get PTE1 address and PTE1 entry index. */ > + movl PTR(XK_VA_PTE1_PAGE)(%esi), %ebx > + movl %eax, %ecx > + shrl $PAGE_SHIFT, %ecx > + andl $(PTRS_PER_PTE - 1), %ecx > + > + /* Fill PTE1 entry with control page reference. */ > + movl PTR(XK_MA_CONTROL_PAGE)(%esi), %edx > + orl $__PAGE_KERNEL_EXEC, %edx > + movl %edx, (%ebx, %ecx, 8) > + > + /* > + * Get machine address of control page now. > + * This is impossible after page table switch. > + */ > + movl PTR(XK_MA_CONTROL_PAGE)(%esi), %ebx > + > + /* Get machine address of transition page table now too. */ > + movl PTR(XK_MA_PGD_PAGE)(%esi), %ecx > + > + /* Get start_address too. */ > + movl ARG_START_ADDRESS(%esp), %edx > + > + /* Get indirection_page address too. */ > + movl ARG_INDIRECTION_PAGE(%esp), %edi > + > + /* Switch to transition page table. */ > + movl %ecx, %cr3 > + > + /* Load IDT. */ > + lidtl (idt_48 - xen_relocate_kernel)(%ebx) > + > + /* Load GDT. */ > + leal (gdt - xen_relocate_kernel)(%ebx), %eax > + movl %eax, (gdt_48 - xen_relocate_kernel + 2)(%ebx) > + lgdtl (gdt_48 - xen_relocate_kernel)(%ebx) > + > + /* Load data segment registers. */ > + movl $(gdt_ds - gdt), %eax > + movl %eax, %ds > + movl %eax, %es > + movl %eax, %fs > + movl %eax, %gs > + movl %eax, %ss > + > + /* Setup a new stack at the end of machine address of control page. */ > + leal PAGE_SIZE(%ebx), %esp > + > + /* Store start_address on the stack. */ > + pushl %edx > + > + /* Jump to identity mapped page. */ > + pushl $0 > + pushl $(gdt_cs - gdt) > + addl $(identity_mapped - xen_relocate_kernel), %ebx > + pushl %ebx > + iretl > + > +identity_mapped: > + /* > + * Set %cr0 to a known state: > + * - disable alignment check, > + * - disable floating point emulation, > + * - disable paging, > + * - no task switch, > + * - disable write protect, > + * - enable protected mode. > + */ > + movl %cr0, %eax > + andl $~(X86_CR0_AM | X86_CR0_EM | X86_CR0_PG | X86_CR0_TS | > X86_CR0_WP), %eax > + orl $(X86_CR0_PE), %eax > + movl %eax, %cr0 > + > + /* Set %cr4 to a known state. */ > + xorl %eax, %eax > + movl %eax, %cr4 > + > + jmp 1f > + > +1: > + /* Flush the TLB (needed?). */ > + movl %eax, %cr3 > + > + /* Do the copies. */ > + movl %edi, %ecx /* Put the indirection_page in %ecx. */ > + xorl %edi, %edi > + xorl %esi, %esi > + jmp 1f > + > +0: > + /* > + * Top, read another doubleword from the indirection page. > + * Indirection page is an array which contains source > + * and destination address pairs. If all pairs could > + * not fit in one page then at the end of given > + * indirection page is pointer to next one. > + * Copy is stopped when done indicator > + * is found in indirection page. > + */ > + movl (%ebx), %ecx > + addl $4, %ebx > + > +1: > + testl $0x1, %ecx /* Is it a destination page? */ > + jz 2f > + > + movl %ecx, %edi > + andl $PAGE_MASK, %edi > + jmp 0b > + > +2: > + testl $0x2, %ecx /* Is it an indirection page? */ > + jz 2f > + > + movl %ecx, %ebx > + andl $PAGE_MASK, %ebx > + jmp 0b > + > +2: > + testl $0x4, %ecx /* Is it the done indicator? */ > + jz 2f > + jmp 3f > + > +2: > + testl $0x8, %ecx /* Is it the source indicator? */ > + jz 0b /* Ignore it otherwise. */ > + > + movl %ecx, %esi > + andl $PAGE_MASK, %esi > + movl $1024, %ecx > + > + /* Copy page. */ > + rep movsl > + jmp 0b > + > +3: > + /* > + * To be certain of avoiding problems with self-modifying code > + * I need to execute a serializing instruction here. > + * So I flush the TLB by reloading %cr3 here, it's handy, > + * and not processor dependent. > + */ > + xorl %eax, %eax > + movl %eax, %cr3 > + > + /* > + * Set all of the registers to known values. > + * Leave %esp alone. > + */ > + xorl %ebx, %ebx > + xorl %ecx, %ecx > + xorl %edx, %edx > + xorl %esi, %esi > + xorl %edi, %edi > + xorl %ebp, %ebp > + > + /* Jump to start_address. */ > + retl > + > + .align L1_CACHE_BYTES > + > +gdt: > + .quad 0x0000000000000000 /* NULL descriptor. */ > + > +gdt_cs: > + .quad 0x00cf9a000000ffff /* 4 GiB code segment at 0x00000000. */ > + > +gdt_ds: > + .quad 0x00cf92000000ffff /* 4 GiB data segment at 0x00000000. */ > +gdt_end: > + > +gdt_48: > + .word gdt_end - gdt - 1 /* GDT limit. */ > + .long 0 /* GDT base - filled in by code above. > */ > + > +idt_48: > + .word 0 /* IDT limit. */ > + .long 0 /* IDT base. */ > + > +xen_kexec_control_code_size: > + .long . - xen_relocate_kernel > -- > 1.5.6.5 _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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