| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * PPC64 code to handle Linux booting another kernel. |
| * |
| * Copyright (C) 2004-2005, IBM Corp. |
| * |
| * Created by: Milton D Miller II |
| */ |
| |
| |
| #include <linux/kexec.h> |
| #include <linux/smp.h> |
| #include <linux/thread_info.h> |
| #include <linux/init_task.h> |
| #include <linux/errno.h> |
| #include <linux/kernel.h> |
| #include <linux/cpu.h> |
| #include <linux/hardirq.h> |
| #include <linux/of.h> |
| #include <linux/libfdt.h> |
| |
| #include <asm/page.h> |
| #include <asm/current.h> |
| #include <asm/machdep.h> |
| #include <asm/cacheflush.h> |
| #include <asm/firmware.h> |
| #include <asm/paca.h> |
| #include <asm/mmu.h> |
| #include <asm/sections.h> /* _end */ |
| #include <asm/setup.h> |
| #include <asm/smp.h> |
| #include <asm/hw_breakpoint.h> |
| #include <asm/svm.h> |
| #include <asm/ultravisor.h> |
| #include <asm/crashdump-ppc64.h> |
| |
| int machine_kexec_prepare(struct kimage *image) |
| { |
| int i; |
| unsigned long begin, end; /* limits of segment */ |
| unsigned long low, high; /* limits of blocked memory range */ |
| struct device_node *node; |
| const unsigned long *basep; |
| const unsigned int *sizep; |
| |
| /* |
| * Since we use the kernel fault handlers and paging code to |
| * handle the virtual mode, we must make sure no destination |
| * overlaps kernel static data or bss. |
| */ |
| for (i = 0; i < image->nr_segments; i++) |
| if (image->segment[i].mem < __pa(_end)) |
| return -ETXTBSY; |
| |
| /* We also should not overwrite the tce tables */ |
| for_each_node_by_type(node, "pci") { |
| basep = of_get_property(node, "linux,tce-base", NULL); |
| sizep = of_get_property(node, "linux,tce-size", NULL); |
| if (basep == NULL || sizep == NULL) |
| continue; |
| |
| low = *basep; |
| high = low + (*sizep); |
| |
| for (i = 0; i < image->nr_segments; i++) { |
| begin = image->segment[i].mem; |
| end = begin + image->segment[i].memsz; |
| |
| if ((begin < high) && (end > low)) { |
| of_node_put(node); |
| return -ETXTBSY; |
| } |
| } |
| } |
| |
| return 0; |
| } |
| |
| /* Called during kexec sequence with MMU off */ |
| static notrace void copy_segments(unsigned long ind) |
| { |
| unsigned long entry; |
| unsigned long *ptr; |
| void *dest; |
| void *addr; |
| |
| /* |
| * We rely on kexec_load to create a lists that properly |
| * initializes these pointers before they are used. |
| * We will still crash if the list is wrong, but at least |
| * the compiler will be quiet. |
| */ |
| ptr = NULL; |
| dest = NULL; |
| |
| for (entry = ind; !(entry & IND_DONE); entry = *ptr++) { |
| addr = __va(entry & PAGE_MASK); |
| |
| switch (entry & IND_FLAGS) { |
| case IND_DESTINATION: |
| dest = addr; |
| break; |
| case IND_INDIRECTION: |
| ptr = addr; |
| break; |
| case IND_SOURCE: |
| copy_page(dest, addr); |
| dest += PAGE_SIZE; |
| } |
| } |
| } |
| |
| /* Called during kexec sequence with MMU off */ |
| notrace void kexec_copy_flush(struct kimage *image) |
| { |
| long i, nr_segments = image->nr_segments; |
| struct kexec_segment ranges[KEXEC_SEGMENT_MAX]; |
| |
| /* save the ranges on the stack to efficiently flush the icache */ |
| memcpy(ranges, image->segment, sizeof(ranges)); |
| |
| /* |
| * After this call we may not use anything allocated in dynamic |
| * memory, including *image. |
| * |
| * Only globals and the stack are allowed. |
| */ |
| copy_segments(image->head); |
| |
| /* |
| * we need to clear the icache for all dest pages sometime, |
| * including ones that were in place on the original copy |
| */ |
| for (i = 0; i < nr_segments; i++) |
| flush_icache_range((unsigned long)__va(ranges[i].mem), |
| (unsigned long)__va(ranges[i].mem + ranges[i].memsz)); |
| } |
| |
| #ifdef CONFIG_SMP |
| |
| static int kexec_all_irq_disabled = 0; |
| |
| static void kexec_smp_down(void *arg) |
| { |
| local_irq_disable(); |
| hard_irq_disable(); |
| |
| mb(); /* make sure our irqs are disabled before we say they are */ |
| get_paca()->kexec_state = KEXEC_STATE_IRQS_OFF; |
| while(kexec_all_irq_disabled == 0) |
| cpu_relax(); |
| mb(); /* make sure all irqs are disabled before this */ |
| hw_breakpoint_disable(); |
| /* |
| * Now every CPU has IRQs off, we can clear out any pending |
| * IPIs and be sure that no more will come in after this. |
| */ |
| if (ppc_md.kexec_cpu_down) |
| ppc_md.kexec_cpu_down(0, 1); |
| |
| reset_sprs(); |
| |
| kexec_smp_wait(); |
| /* NOTREACHED */ |
| } |
| |
| static void kexec_prepare_cpus_wait(int wait_state) |
| { |
| int my_cpu, i, notified=-1; |
| |
| hw_breakpoint_disable(); |
| my_cpu = get_cpu(); |
| /* Make sure each CPU has at least made it to the state we need. |
| * |
| * FIXME: There is a (slim) chance of a problem if not all of the CPUs |
| * are correctly onlined. If somehow we start a CPU on boot with RTAS |
| * start-cpu, but somehow that CPU doesn't write callin_cpu_map[] in |
| * time, the boot CPU will timeout. If it does eventually execute |
| * stuff, the secondary will start up (paca_ptrs[]->cpu_start was |
| * written) and get into a peculiar state. |
| * If the platform supports smp_ops->take_timebase(), the secondary CPU |
| * will probably be spinning in there. If not (i.e. pseries), the |
| * secondary will continue on and try to online itself/idle/etc. If it |
| * survives that, we need to find these |
| * possible-but-not-online-but-should-be CPUs and chaperone them into |
| * kexec_smp_wait(). |
| */ |
| for_each_online_cpu(i) { |
| if (i == my_cpu) |
| continue; |
| |
| while (paca_ptrs[i]->kexec_state < wait_state) { |
| barrier(); |
| if (i != notified) { |
| printk(KERN_INFO "kexec: waiting for cpu %d " |
| "(physical %d) to enter %i state\n", |
| i, paca_ptrs[i]->hw_cpu_id, wait_state); |
| notified = i; |
| } |
| } |
| } |
| mb(); |
| } |
| |
| /* |
| * We need to make sure each present CPU is online. The next kernel will scan |
| * the device tree and assume primary threads are online and query secondary |
| * threads via RTAS to online them if required. If we don't online primary |
| * threads, they will be stuck. However, we also online secondary threads as we |
| * may be using 'cede offline'. In this case RTAS doesn't see the secondary |
| * threads as offline -- and again, these CPUs will be stuck. |
| * |
| * So, we online all CPUs that should be running, including secondary threads. |
| */ |
| static void wake_offline_cpus(void) |
| { |
| int cpu = 0; |
| |
| for_each_present_cpu(cpu) { |
| if (!cpu_online(cpu)) { |
| printk(KERN_INFO "kexec: Waking offline cpu %d.\n", |
| cpu); |
| WARN_ON(add_cpu(cpu)); |
| } |
| } |
| } |
| |
| static void kexec_prepare_cpus(void) |
| { |
| wake_offline_cpus(); |
| smp_call_function(kexec_smp_down, NULL, /* wait */0); |
| local_irq_disable(); |
| hard_irq_disable(); |
| |
| mb(); /* make sure IRQs are disabled before we say they are */ |
| get_paca()->kexec_state = KEXEC_STATE_IRQS_OFF; |
| |
| kexec_prepare_cpus_wait(KEXEC_STATE_IRQS_OFF); |
| /* we are sure every CPU has IRQs off at this point */ |
| kexec_all_irq_disabled = 1; |
| |
| /* |
| * Before removing MMU mappings make sure all CPUs have entered real |
| * mode: |
| */ |
| kexec_prepare_cpus_wait(KEXEC_STATE_REAL_MODE); |
| |
| /* after we tell the others to go down */ |
| if (ppc_md.kexec_cpu_down) |
| ppc_md.kexec_cpu_down(0, 0); |
| |
| put_cpu(); |
| } |
| |
| #else /* ! SMP */ |
| |
| static void kexec_prepare_cpus(void) |
| { |
| /* |
| * move the secondarys to us so that we can copy |
| * the new kernel 0-0x100 safely |
| * |
| * do this if kexec in setup.c ? |
| * |
| * We need to release the cpus if we are ever going from an |
| * UP to an SMP kernel. |
| */ |
| smp_release_cpus(); |
| if (ppc_md.kexec_cpu_down) |
| ppc_md.kexec_cpu_down(0, 0); |
| local_irq_disable(); |
| hard_irq_disable(); |
| } |
| |
| #endif /* SMP */ |
| |
| /* |
| * kexec thread structure and stack. |
| * |
| * We need to make sure that this is 16384-byte aligned due to the |
| * way process stacks are handled. It also must be statically allocated |
| * or allocated as part of the kimage, because everything else may be |
| * overwritten when we copy the kexec image. We piggyback on the |
| * "init_task" linker section here to statically allocate a stack. |
| * |
| * We could use a smaller stack if we don't care about anything using |
| * current, but that audit has not been performed. |
| */ |
| static union thread_union kexec_stack = { }; |
| |
| /* |
| * For similar reasons to the stack above, the kexecing CPU needs to be on a |
| * static PACA; we switch to kexec_paca. |
| */ |
| static struct paca_struct kexec_paca; |
| |
| /* Our assembly helper, in misc_64.S */ |
| extern void kexec_sequence(void *newstack, unsigned long start, |
| void *image, void *control, |
| void (*clear_all)(void), |
| bool copy_with_mmu_off) __noreturn; |
| |
| /* too late to fail here */ |
| void default_machine_kexec(struct kimage *image) |
| { |
| bool copy_with_mmu_off; |
| |
| /* prepare control code if any */ |
| |
| /* |
| * If the kexec boot is the normal one, need to shutdown other cpus |
| * into our wait loop and quiesce interrupts. |
| * Otherwise, in the case of crashed mode (crashing_cpu >= 0), |
| * stopping other CPUs and collecting their pt_regs is done before |
| * using debugger IPI. |
| */ |
| |
| if (!kdump_in_progress()) |
| kexec_prepare_cpus(); |
| |
| #ifdef CONFIG_PPC_PSERIES |
| /* |
| * This must be done after other CPUs have shut down, otherwise they |
| * could execute the 'scv' instruction, which is not supported with |
| * reloc disabled (see configure_exceptions()). |
| */ |
| if (firmware_has_feature(FW_FEATURE_SET_MODE)) |
| pseries_disable_reloc_on_exc(); |
| #endif |
| |
| printk("kexec: Starting switchover sequence.\n"); |
| |
| /* switch to a staticly allocated stack. Based on irq stack code. |
| * We setup preempt_count to avoid using VMX in memcpy. |
| * XXX: the task struct will likely be invalid once we do the copy! |
| */ |
| current_thread_info()->flags = 0; |
| current_thread_info()->preempt_count = HARDIRQ_OFFSET; |
| |
| /* We need a static PACA, too; copy this CPU's PACA over and switch to |
| * it. Also poison per_cpu_offset and NULL lppaca to catch anyone using |
| * non-static data. |
| */ |
| memcpy(&kexec_paca, get_paca(), sizeof(struct paca_struct)); |
| kexec_paca.data_offset = 0xedeaddeadeeeeeeeUL; |
| #ifdef CONFIG_PPC_PSERIES |
| kexec_paca.lppaca_ptr = NULL; |
| #endif |
| |
| if (is_secure_guest() && !(image->preserve_context || |
| image->type == KEXEC_TYPE_CRASH)) { |
| uv_unshare_all_pages(); |
| printk("kexec: Unshared all shared pages.\n"); |
| } |
| |
| paca_ptrs[kexec_paca.paca_index] = &kexec_paca; |
| |
| setup_paca(&kexec_paca); |
| |
| /* |
| * The lppaca should be unregistered at this point so the HV won't |
| * touch it. In the case of a crash, none of the lppacas are |
| * unregistered so there is not much we can do about it here. |
| */ |
| |
| /* |
| * On Book3S, the copy must happen with the MMU off if we are either |
| * using Radix page tables or we are not in an LPAR since we can |
| * overwrite the page tables while copying. |
| * |
| * In an LPAR, we keep the MMU on otherwise we can't access beyond |
| * the RMA. On BookE there is no real MMU off mode, so we have to |
| * keep it enabled as well (but then we have bolted TLB entries). |
| */ |
| #ifdef CONFIG_PPC_BOOK3E_64 |
| copy_with_mmu_off = false; |
| #else |
| copy_with_mmu_off = radix_enabled() || |
| !(firmware_has_feature(FW_FEATURE_LPAR) || |
| firmware_has_feature(FW_FEATURE_PS3_LV1)); |
| #endif |
| |
| /* Some things are best done in assembly. Finding globals with |
| * a toc is easier in C, so pass in what we can. |
| */ |
| kexec_sequence(&kexec_stack, image->start, image, |
| page_address(image->control_code_page), |
| mmu_cleanup_all, copy_with_mmu_off); |
| /* NOTREACHED */ |
| } |
| |
| #ifdef CONFIG_PPC_64S_HASH_MMU |
| /* Values we need to export to the second kernel via the device tree. */ |
| static __be64 htab_base; |
| static __be64 htab_size; |
| |
| static struct property htab_base_prop = { |
| .name = "linux,htab-base", |
| .length = sizeof(unsigned long), |
| .value = &htab_base, |
| }; |
| |
| static struct property htab_size_prop = { |
| .name = "linux,htab-size", |
| .length = sizeof(unsigned long), |
| .value = &htab_size, |
| }; |
| |
| static int __init export_htab_values(void) |
| { |
| struct device_node *node; |
| |
| /* On machines with no htab htab_address is NULL */ |
| if (!htab_address) |
| return -ENODEV; |
| |
| node = of_find_node_by_path("/chosen"); |
| if (!node) |
| return -ENODEV; |
| |
| /* remove any stale properties so ours can be found */ |
| of_remove_property(node, of_find_property(node, htab_base_prop.name, NULL)); |
| of_remove_property(node, of_find_property(node, htab_size_prop.name, NULL)); |
| |
| htab_base = cpu_to_be64(__pa(htab_address)); |
| of_add_property(node, &htab_base_prop); |
| htab_size = cpu_to_be64(htab_size_bytes); |
| of_add_property(node, &htab_size_prop); |
| |
| of_node_put(node); |
| return 0; |
| } |
| late_initcall(export_htab_values); |
| #endif /* CONFIG_PPC_64S_HASH_MMU */ |
| |
| #if defined(CONFIG_KEXEC_FILE) || defined(CONFIG_CRASH_DUMP) |
| /** |
| * add_node_props - Reads node properties from device node structure and add |
| * them to fdt. |
| * @fdt: Flattened device tree of the kernel |
| * @node_offset: offset of the node to add a property at |
| * @dn: device node pointer |
| * |
| * Returns 0 on success, negative errno on error. |
| */ |
| static int add_node_props(void *fdt, int node_offset, const struct device_node *dn) |
| { |
| int ret = 0; |
| struct property *pp; |
| |
| if (!dn) |
| return -EINVAL; |
| |
| for_each_property_of_node(dn, pp) { |
| ret = fdt_setprop(fdt, node_offset, pp->name, pp->value, pp->length); |
| if (ret < 0) { |
| pr_err("Unable to add %s property: %s\n", pp->name, fdt_strerror(ret)); |
| return ret; |
| } |
| } |
| return ret; |
| } |
| |
| /** |
| * update_cpus_node - Update cpus node of flattened device tree using of_root |
| * device node. |
| * @fdt: Flattened device tree of the kernel. |
| * |
| * Returns 0 on success, negative errno on error. |
| */ |
| int update_cpus_node(void *fdt) |
| { |
| struct device_node *cpus_node, *dn; |
| int cpus_offset, cpus_subnode_offset, ret = 0; |
| |
| cpus_offset = fdt_path_offset(fdt, "/cpus"); |
| if (cpus_offset < 0 && cpus_offset != -FDT_ERR_NOTFOUND) { |
| pr_err("Malformed device tree: error reading /cpus node: %s\n", |
| fdt_strerror(cpus_offset)); |
| return cpus_offset; |
| } |
| |
| if (cpus_offset > 0) { |
| ret = fdt_del_node(fdt, cpus_offset); |
| if (ret < 0) { |
| pr_err("Error deleting /cpus node: %s\n", fdt_strerror(ret)); |
| return -EINVAL; |
| } |
| } |
| |
| /* Add cpus node to fdt */ |
| cpus_offset = fdt_add_subnode(fdt, fdt_path_offset(fdt, "/"), "cpus"); |
| if (cpus_offset < 0) { |
| pr_err("Error creating /cpus node: %s\n", fdt_strerror(cpus_offset)); |
| return -EINVAL; |
| } |
| |
| /* Add cpus node properties */ |
| cpus_node = of_find_node_by_path("/cpus"); |
| ret = add_node_props(fdt, cpus_offset, cpus_node); |
| of_node_put(cpus_node); |
| if (ret < 0) |
| return ret; |
| |
| /* Loop through all subnodes of cpus and add them to fdt */ |
| for_each_node_by_type(dn, "cpu") { |
| cpus_subnode_offset = fdt_add_subnode(fdt, cpus_offset, dn->full_name); |
| if (cpus_subnode_offset < 0) { |
| pr_err("Unable to add %s subnode: %s\n", dn->full_name, |
| fdt_strerror(cpus_subnode_offset)); |
| ret = cpus_subnode_offset; |
| goto out; |
| } |
| |
| ret = add_node_props(fdt, cpus_subnode_offset, dn); |
| if (ret < 0) |
| goto out; |
| } |
| out: |
| of_node_put(dn); |
| return ret; |
| } |
| #endif /* CONFIG_KEXEC_FILE || CONFIG_CRASH_DUMP */ |