[PATCH v3 07/11] x86/xen: Add x86_64 kexec/kdump implementation

Daniel Kiper
2012-12-27T02:20:40Z

Add x86_64 kexec/kdump implementation.

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
---
arch/x86/xen/machine_kexec_64.c | 318 +++++++++++++++++++++++++++++++++++++
arch/x86/xen/relocate_kernel_64.S | 309 +++++++++++++++++++++++++++++++++++
2 files changed, 627 insertions(+), 0 deletions(-)
create mode 100644 arch/x86/xen/machine_kexec_64.c
create mode 100644 arch/x86/xen/relocate_kernel_64.S

diff --git a/arch/x86/xen/machine_kexec_64.c b/arch/x86/xen/machine_kexec_64.c
new file mode 100644
index 0000000..2600342
--- /dev/null
+++ b/arch/x86/xen/machine_kexec_64.c
@@ -0,0 +1,318 @@
+/*
+ * 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/kernel.h>
+#include <linux/kexec.h>
+#include <linux/mm.h>
+#include <linux/string.h>
+
+#include <xen/interface/memory.h>
+#include <xen/xen.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 void init_level2_page(pmd_t *pmd, unsigned long addr)
+{
+ unsigned long end_addr = addr + PUD_SIZE;
+
+ while (addr < end_addr) {
+ native_set_pmd(pmd++, native_make_pmd(addr | __PAGE_KERNEL_LARGE_EXEC));
+ addr += PMD_SIZE;
+ }
+}
+
+static int init_level3_page(struct kimage *image, pud_t *pud,
+ unsigned long addr, unsigned long last_addr)
+{
+ pmd_t *pmd;
+ struct page *page;
+ unsigned long end_addr = addr + PGDIR_SIZE;
+
+ while ((addr < last_addr) && (addr < end_addr)) {
+ page = firmware_kimage_alloc_control_pages(image, 0);
+
+ if (!page)
+ return -ENOMEM;
+
+ pmd = page_address(page);
+ init_level2_page(pmd, addr);
+ native_set_pud(pud++, native_make_pud(__ma(pmd) | _KERNPG_TABLE));
+ addr += PUD_SIZE;
+ }
+
+ /* Clear the unused entries. */
+ while (addr < end_addr) {
+ native_pud_clear(pud++);
+ addr += PUD_SIZE;
+ }
+
+ return 0;
+}
+
+
+static int init_level4_page(struct kimage *image, pgd_t *pgd,
+ unsigned long addr, unsigned long last_addr)
+{
+ int rc;
+ pud_t *pud;
+ struct page *page;
+ unsigned long end_addr = addr + PTRS_PER_PGD * PGDIR_SIZE;
+
+ while ((addr < last_addr) && (addr < end_addr)) {
+ page = firmware_kimage_alloc_control_pages(image, 0);
+
+ if (!page)
+ return -ENOMEM;
+
+ pud = page_address(page);
+ rc = init_level3_page(image, pud, addr, last_addr);
+
+ if (rc)
+ return rc;
+
+ native_set_pgd(pgd++, native_make_pgd(__ma(pud) | _KERNPG_TABLE));
+ addr += PGDIR_SIZE;
+ }
+
+ /* Clear the unused entries. */
+ while (addr < end_addr) {
+ native_pgd_clear(pgd++);
+ addr += PGDIR_SIZE;
+ }
+
+ return 0;
+}
+
+static void free_transition_pgtable(struct kimage *image)
+{
+ free_page((unsigned long)image->arch.pgd);
+ free_page((unsigned long)image->arch.pud0);
+ free_page((unsigned long)image->arch.pud1);
+ 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.pud0 = (pud_t *)get_zeroed_page(GFP_KERNEL);
+
+ if (!image->arch.pud0)
+ goto err;
+
+ image->arch.pud1 = (pud_t *)get_zeroed_page(GFP_KERNEL);
+
+ if (!image->arch.pud1)
+ 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 init_pgtable(struct kimage *image, pgd_t *pgd)
+{
+ int rc;
+ unsigned long max_mfn;
+
+ max_mfn = HYPERVISOR_memory_op(XENMEM_maximum_ram_page, NULL);
+
+ rc = init_level4_page(image, pgd, 0, PFN_PHYS(max_mfn));
+
+ if (rc)
+ return rc;
+
+ return alloc_transition_pgtable(image);
+}
+
+struct page *mf_kexec_kimage_alloc_pages(gfp_t gfp_mask,
+ unsigned int order,
+ unsigned long limit)
+{
+ struct page *pages;
+ unsigned int i;
+
+ pages = alloc_pages(gfp_mask, order);
+
+ if (!pages)
+ return NULL;
+
+ BUG_ON(PagePrivate(pages));
+
+ pages->mapping = NULL;
+ set_page_private(pages, order);
+
+ for (i = 0; i < (1 << order); ++i)
+ SetPageReserved(pages + i);
+
+ return pages;
+}
+
+void mf_kexec_kimage_free_pages(struct page *page)
+{
+ unsigned int i, order;
+
+ order = page_private(page);
+
+ for (i = 0; i < (1 << order); ++i)
+ ClearPageReserved(page + i);
+
+ __free_pages(page, order);
+}
+
+unsigned long mf_kexec_page_to_pfn(struct page *page)
+{
+ return pfn_to_mfn(page_to_pfn(page));
+}
+
+struct page *mf_kexec_pfn_to_page(unsigned long mfn)
+{
+ return pfn_to_page(mfn_to_pfn(mfn));
+}
+
+unsigned long mf_kexec_virt_to_phys(volatile void *address)
+{
+ return virt_to_machine(address).maddr;
+}
+
+void *mf_kexec_phys_to_virt(unsigned long address)
+{
+ return phys_to_virt(machine_to_phys(XMADDR(address)).paddr);
+}
+
+int mf_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 init_pgtable(image, page_address(image->control_code_page));
+}
+
+int mf_kexec_load(struct kimage *image)
+{
+ void *control_page, *table_page;
+ struct xen_kexec_load xkl = {};
+
+ /* Image is unloaded, nothing to do. */
+ if (!image)
+ return 0;
+
+ table_page = page_address(image->control_code_page);
+ control_page = table_page + PAGE_SIZE;
+
+ 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] = __ma(table_page);
+ xkl.image.page_list[XK_MA_PGD_PAGE] = __ma(image->arch.pgd);
+ xkl.image.page_list[XK_MA_PUD0_PAGE] = __ma(image->arch.pud0);
+ xkl.image.page_list[XK_MA_PUD1_PAGE] = __ma(image->arch.pud1);
+ 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);
+}
+
+void mf_kexec_cleanup(struct kimage *image)
+{
+ free_transition_pgtable(image);
+}
+
+void mf_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);
+}
+
+void mf_kexec_shutdown(void)
+{
+}
+
+void mf_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();
+}
diff --git a/arch/x86/xen/relocate_kernel_64.S b/arch/x86/xen/relocate_kernel_64.S
new file mode 100644
index 0000000..8f641f1
--- /dev/null
+++ b/arch/x86/xen/relocate_kernel_64.S
@@ -0,0 +1,309 @@
+/*
+ * Copyright (c) 2002-2005 Eric Biederman <ebiederm@xmission.com>
+ * 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 <asm/page_types.h>
+#include <asm/pgtable_types.h>
+#include <asm/processor-flags.h>
+
+#include <asm/xen/kexec.h>
+
+#define PTR(x) (x << 3)
+
+ .text
+ .code64
+ .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.
+ *
+ * %rdi - indirection_page,
+ * %rsi - page_list,
+ * %rdx - start_address,
+ * %ecx - preserve_context (ignored).
+ */
+
+ /* Zero out flags, and disable interrupts. */
+ pushq $0
+ popfq
+
+ /*
+ * Map the control page at its virtual address
+ * in transition page table.
+ */
+ movq PTR(XK_VA_CONTROL_PAGE)(%rsi), %r8
+
+ /* Get PGD address and PGD entry index. */
+ movq PTR(XK_VA_PGD_PAGE)(%rsi), %r9
+ movq %r8, %r10
+ shrq $PGDIR_SHIFT, %r10
+ andq $(PTRS_PER_PGD - 1), %r10
+
+ /* Fill PGD entry with PUD0 reference. */
+ movq PTR(XK_MA_PUD0_PAGE)(%rsi), %r11
+ orq $_KERNPG_TABLE, %r11
+ movq %r11, (%r9, %r10, 8)
+
+ /* Get PUD0 address and PUD0 entry index. */
+ movq PTR(XK_VA_PUD0_PAGE)(%rsi), %r9
+ movq %r8, %r10
+ shrq $PUD_SHIFT, %r10
+ andq $(PTRS_PER_PUD - 1), %r10
+
+ /* Fill PUD0 entry with PMD0 reference. */
+ movq PTR(XK_MA_PMD0_PAGE)(%rsi), %r11
+ orq $_KERNPG_TABLE, %r11
+ movq %r11, (%r9, %r10, 8)
+
+ /* Get PMD0 address and PMD0 entry index. */
+ movq PTR(XK_VA_PMD0_PAGE)(%rsi), %r9
+ movq %r8, %r10
+ shrq $PMD_SHIFT, %r10
+ andq $(PTRS_PER_PMD - 1), %r10
+
+ /* Fill PMD0 entry with PTE0 reference. */
+ movq PTR(XK_MA_PTE0_PAGE)(%rsi), %r11
+ orq $_KERNPG_TABLE, %r11
+ movq %r11, (%r9, %r10, 8)
+
+ /* Get PTE0 address and PTE0 entry index. */
+ movq PTR(XK_VA_PTE0_PAGE)(%rsi), %r9
+ movq %r8, %r10
+ shrq $PAGE_SHIFT, %r10
+ andq $(PTRS_PER_PTE - 1), %r10
+
+ /* Fill PTE0 entry with control page reference. */
+ movq PTR(XK_MA_CONTROL_PAGE)(%rsi), %r11
+ orq $__PAGE_KERNEL_EXEC, %r11
+ movq %r11, (%r9, %r10, 8)
+
+ /*
+ * Identity map the control page at its machine address
+ * in transition page table.
+ */
+ movq PTR(XK_MA_CONTROL_PAGE)(%rsi), %r8
+
+ /* Get PGD address and PGD entry index. */
+ movq PTR(XK_VA_PGD_PAGE)(%rsi), %r9
+ movq %r8, %r10
+ shrq $PGDIR_SHIFT, %r10
+ andq $(PTRS_PER_PGD - 1), %r10
+
+ /* Fill PGD entry with PUD1 reference. */
+ movq PTR(XK_MA_PUD1_PAGE)(%rsi), %r11
+ orq $_KERNPG_TABLE, %r11
+ movq %r11, (%r9, %r10, 8)
+
+ /* Get PUD1 address and PUD1 entry index. */
+ movq PTR(XK_VA_PUD1_PAGE)(%rsi), %r9
+ movq %r8, %r10
+ shrq $PUD_SHIFT, %r10
+ andq $(PTRS_PER_PUD - 1), %r10
+
+ /* Fill PUD1 entry with PMD1 reference. */
+ movq PTR(XK_MA_PMD1_PAGE)(%rsi), %r11
+ orq $_KERNPG_TABLE, %r11
+ movq %r11, (%r9, %r10, 8)
+
+ /* Get PMD1 address and PMD1 entry index. */
+ movq PTR(XK_VA_PMD1_PAGE)(%rsi), %r9
+ movq %r8, %r10
+ shrq $PMD_SHIFT, %r10
+ andq $(PTRS_PER_PMD - 1), %r10
+
+ /* Fill PMD1 entry with PTE1 reference. */
+ movq PTR(XK_MA_PTE1_PAGE)(%rsi), %r11
+ orq $_KERNPG_TABLE, %r11
+ movq %r11, (%r9, %r10, 8)
+
+ /* Get PTE1 address and PTE1 entry index. */
+ movq PTR(XK_VA_PTE1_PAGE)(%rsi), %r9
+ movq %r8, %r10
+ shrq $PAGE_SHIFT, %r10
+ andq $(PTRS_PER_PTE - 1), %r10
+
+ /* Fill PTE1 entry with control page reference. */
+ movq PTR(XK_MA_CONTROL_PAGE)(%rsi), %r11
+ orq $__PAGE_KERNEL_EXEC, %r11
+ movq %r11, (%r9, %r10, 8)
+
+ /*
+ * Get machine address of control page now.
+ * This is impossible after page table switch.
+ */
+ movq PTR(XK_MA_CONTROL_PAGE)(%rsi), %r8
+
+ /* Get machine address of identity page table now too. */
+ movq PTR(XK_MA_TABLE_PAGE)(%rsi), %r9
+
+ /* Get machine address of transition page table now too. */
+ movq PTR(XK_MA_PGD_PAGE)(%rsi), %r10
+
+ /* Switch to transition page table. */
+ movq %r10, %cr3
+
+ /* Setup a new stack at the end of machine address of control page. */
+ leaq PAGE_SIZE(%r8), %rsp
+
+ /* Store start_address on the stack. */
+ pushq %rdx
+
+ /* Jump to identity mapped page. */
+ addq $(identity_mapped - xen_relocate_kernel), %r8
+ jmpq *%r8
+
+identity_mapped:
+ /* Switch to identity page table. */
+ movq %r9, %cr3
+
+ /*
+ * Set %cr0 to a known state:
+ * - disable alignment check,
+ * - disable floating point emulation,
+ * - no task switch,
+ * - disable write protect,
+ * - enable protected mode,
+ * - enable paging.
+ */
+ movq %cr0, %rax
+ andq $~(X86_CR0_AM | X86_CR0_EM | X86_CR0_TS | X86_CR0_WP), %rax
+ orl $(X86_CR0_PE | X86_CR0_PG), %eax
+ movq %rax, %cr0
+
+ /*
+ * Set %cr4 to a known state:
+ * - enable physical address extension.
+ */
+ movq $X86_CR4_PAE, %rax
+ movq %rax, %cr4
+
+ jmp 1f
+
+1:
+ /* Flush the TLB (needed?). */
+ movq %r9, %cr3
+
+ /* Do the copies. */
+ movq %rdi, %rcx /* Put the indirection_page in %rcx. */
+ xorq %rdi, %rdi
+ xorq %rsi, %rsi
+ jmp 1f
+
+0:
+ /*
+ * Top, read another quadword 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.
+ */
+ movq (%rbx), %rcx
+ addq $8, %rbx
+
+1:
+ testq $0x1, %rcx /* Is it a destination page? */
+ jz 2f
+
+ movq %rcx, %rdi
+ andq $PAGE_MASK, %rdi
+ jmp 0b
+
+2:
+ testq $0x2, %rcx /* Is it an indirection page? */
+ jz 2f
+
+ movq %rcx, %rbx
+ andq $PAGE_MASK, %rbx
+ jmp 0b
+
+2:
+ testq $0x4, %rcx /* Is it the done indicator? */
+ jz 2f
+ jmp 3f
+
+2:
+ testq $0x8, %rcx /* Is it the source indicator? */
+ jz 0b /* Ignore it otherwise. */
+
+ movq %rcx, %rsi
+ andq $PAGE_MASK, %rsi
+ movq $512, %rcx
+
+ /* Copy page. */
+ rep movsq
+ 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.
+ */
+ movq %cr3, %rax
+ movq %rax, %cr3
+
+ /*
+ * Set all of the registers to known values.
+ * Leave %rsp alone.
+ */
+ xorq %rax, %rax
+ xorq %rbx, %rbx
+ xorq %rcx, %rcx
+ xorq %rdx, %rdx
+ xorq %rsi, %rsi
+ xorq %rdi, %rdi
+ xorq %rbp, %rbp
+ xorq %r8, %r8
+ xorq %r9, %r9
+ xorq %r10, %r10
+ xorq %r11, %r11
+ xorq %r12, %r12
+ xorq %r13, %r13
+ xorq %r14, %r14
+ xorq %r15, %r15
+
+ /* Jump to start_address. */
+ retq
+
+xen_kexec_control_code_size:
+ .long . - xen_relocate_kernel
--
1.5.6.5