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419 lines
11 KiB
419 lines
11 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* PPC64 code to handle Linux booting another kernel. |
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* |
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* Copyright (C) 2004-2005, IBM Corp. |
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* |
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* Created by: Milton D Miller II |
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*/ |
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#include <linux/kexec.h> |
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#include <linux/smp.h> |
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#include <linux/thread_info.h> |
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#include <linux/init_task.h> |
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#include <linux/errno.h> |
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#include <linux/kernel.h> |
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#include <linux/cpu.h> |
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#include <linux/hardirq.h> |
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#include <asm/page.h> |
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#include <asm/current.h> |
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#include <asm/machdep.h> |
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#include <asm/cacheflush.h> |
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#include <asm/firmware.h> |
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#include <asm/paca.h> |
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#include <asm/mmu.h> |
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#include <asm/sections.h> /* _end */ |
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#include <asm/prom.h> |
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#include <asm/smp.h> |
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#include <asm/hw_breakpoint.h> |
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#include <asm/asm-prototypes.h> |
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#include <asm/svm.h> |
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#include <asm/ultravisor.h> |
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int default_machine_kexec_prepare(struct kimage *image) |
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{ |
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int i; |
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unsigned long begin, end; /* limits of segment */ |
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unsigned long low, high; /* limits of blocked memory range */ |
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struct device_node *node; |
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const unsigned long *basep; |
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const unsigned int *sizep; |
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/* |
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* Since we use the kernel fault handlers and paging code to |
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* handle the virtual mode, we must make sure no destination |
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* overlaps kernel static data or bss. |
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*/ |
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for (i = 0; i < image->nr_segments; i++) |
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if (image->segment[i].mem < __pa(_end)) |
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return -ETXTBSY; |
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/* We also should not overwrite the tce tables */ |
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for_each_node_by_type(node, "pci") { |
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basep = of_get_property(node, "linux,tce-base", NULL); |
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sizep = of_get_property(node, "linux,tce-size", NULL); |
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if (basep == NULL || sizep == NULL) |
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continue; |
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low = *basep; |
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high = low + (*sizep); |
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for (i = 0; i < image->nr_segments; i++) { |
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begin = image->segment[i].mem; |
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end = begin + image->segment[i].memsz; |
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if ((begin < high) && (end > low)) |
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return -ETXTBSY; |
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} |
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} |
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return 0; |
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} |
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static void copy_segments(unsigned long ind) |
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{ |
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unsigned long entry; |
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unsigned long *ptr; |
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void *dest; |
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void *addr; |
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/* |
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* We rely on kexec_load to create a lists that properly |
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* initializes these pointers before they are used. |
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* We will still crash if the list is wrong, but at least |
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* the compiler will be quiet. |
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*/ |
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ptr = NULL; |
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dest = NULL; |
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for (entry = ind; !(entry & IND_DONE); entry = *ptr++) { |
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addr = __va(entry & PAGE_MASK); |
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switch (entry & IND_FLAGS) { |
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case IND_DESTINATION: |
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dest = addr; |
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break; |
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case IND_INDIRECTION: |
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ptr = addr; |
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break; |
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case IND_SOURCE: |
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copy_page(dest, addr); |
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dest += PAGE_SIZE; |
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} |
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} |
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} |
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void kexec_copy_flush(struct kimage *image) |
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{ |
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long i, nr_segments = image->nr_segments; |
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struct kexec_segment ranges[KEXEC_SEGMENT_MAX]; |
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/* save the ranges on the stack to efficiently flush the icache */ |
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memcpy(ranges, image->segment, sizeof(ranges)); |
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/* |
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* After this call we may not use anything allocated in dynamic |
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* memory, including *image. |
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* |
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* Only globals and the stack are allowed. |
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*/ |
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copy_segments(image->head); |
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/* |
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* we need to clear the icache for all dest pages sometime, |
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* including ones that were in place on the original copy |
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*/ |
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for (i = 0; i < nr_segments; i++) |
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flush_icache_range((unsigned long)__va(ranges[i].mem), |
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(unsigned long)__va(ranges[i].mem + ranges[i].memsz)); |
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} |
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#ifdef CONFIG_SMP |
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static int kexec_all_irq_disabled = 0; |
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static void kexec_smp_down(void *arg) |
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{ |
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local_irq_disable(); |
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hard_irq_disable(); |
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mb(); /* make sure our irqs are disabled before we say they are */ |
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get_paca()->kexec_state = KEXEC_STATE_IRQS_OFF; |
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while(kexec_all_irq_disabled == 0) |
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cpu_relax(); |
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mb(); /* make sure all irqs are disabled before this */ |
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hw_breakpoint_disable(); |
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/* |
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* Now every CPU has IRQs off, we can clear out any pending |
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* IPIs and be sure that no more will come in after this. |
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*/ |
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if (ppc_md.kexec_cpu_down) |
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ppc_md.kexec_cpu_down(0, 1); |
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reset_sprs(); |
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kexec_smp_wait(); |
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/* NOTREACHED */ |
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} |
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static void kexec_prepare_cpus_wait(int wait_state) |
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{ |
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int my_cpu, i, notified=-1; |
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hw_breakpoint_disable(); |
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my_cpu = get_cpu(); |
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/* Make sure each CPU has at least made it to the state we need. |
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* |
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* FIXME: There is a (slim) chance of a problem if not all of the CPUs |
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* are correctly onlined. If somehow we start a CPU on boot with RTAS |
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* start-cpu, but somehow that CPU doesn't write callin_cpu_map[] in |
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* time, the boot CPU will timeout. If it does eventually execute |
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* stuff, the secondary will start up (paca_ptrs[]->cpu_start was |
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* written) and get into a peculiar state. |
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* If the platform supports smp_ops->take_timebase(), the secondary CPU |
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* will probably be spinning in there. If not (i.e. pseries), the |
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* secondary will continue on and try to online itself/idle/etc. If it |
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* survives that, we need to find these |
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* possible-but-not-online-but-should-be CPUs and chaperone them into |
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* kexec_smp_wait(). |
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*/ |
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for_each_online_cpu(i) { |
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if (i == my_cpu) |
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continue; |
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while (paca_ptrs[i]->kexec_state < wait_state) { |
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barrier(); |
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if (i != notified) { |
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printk(KERN_INFO "kexec: waiting for cpu %d " |
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"(physical %d) to enter %i state\n", |
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i, paca_ptrs[i]->hw_cpu_id, wait_state); |
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notified = i; |
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} |
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} |
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} |
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mb(); |
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} |
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/* |
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* We need to make sure each present CPU is online. The next kernel will scan |
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* the device tree and assume primary threads are online and query secondary |
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* threads via RTAS to online them if required. If we don't online primary |
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* threads, they will be stuck. However, we also online secondary threads as we |
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* may be using 'cede offline'. In this case RTAS doesn't see the secondary |
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* threads as offline -- and again, these CPUs will be stuck. |
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* |
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* So, we online all CPUs that should be running, including secondary threads. |
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*/ |
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static void wake_offline_cpus(void) |
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{ |
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int cpu = 0; |
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for_each_present_cpu(cpu) { |
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if (!cpu_online(cpu)) { |
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printk(KERN_INFO "kexec: Waking offline cpu %d.\n", |
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cpu); |
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WARN_ON(add_cpu(cpu)); |
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} |
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} |
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} |
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static void kexec_prepare_cpus(void) |
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{ |
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wake_offline_cpus(); |
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smp_call_function(kexec_smp_down, NULL, /* wait */0); |
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local_irq_disable(); |
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hard_irq_disable(); |
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mb(); /* make sure IRQs are disabled before we say they are */ |
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get_paca()->kexec_state = KEXEC_STATE_IRQS_OFF; |
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kexec_prepare_cpus_wait(KEXEC_STATE_IRQS_OFF); |
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/* we are sure every CPU has IRQs off at this point */ |
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kexec_all_irq_disabled = 1; |
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/* |
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* Before removing MMU mappings make sure all CPUs have entered real |
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* mode: |
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*/ |
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kexec_prepare_cpus_wait(KEXEC_STATE_REAL_MODE); |
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/* after we tell the others to go down */ |
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if (ppc_md.kexec_cpu_down) |
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ppc_md.kexec_cpu_down(0, 0); |
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put_cpu(); |
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} |
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#else /* ! SMP */ |
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static void kexec_prepare_cpus(void) |
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{ |
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/* |
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* move the secondarys to us so that we can copy |
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* the new kernel 0-0x100 safely |
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* |
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* do this if kexec in setup.c ? |
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* |
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* We need to release the cpus if we are ever going from an |
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* UP to an SMP kernel. |
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*/ |
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smp_release_cpus(); |
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if (ppc_md.kexec_cpu_down) |
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ppc_md.kexec_cpu_down(0, 0); |
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local_irq_disable(); |
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hard_irq_disable(); |
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} |
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#endif /* SMP */ |
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/* |
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* kexec thread structure and stack. |
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* |
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* We need to make sure that this is 16384-byte aligned due to the |
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* way process stacks are handled. It also must be statically allocated |
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* or allocated as part of the kimage, because everything else may be |
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* overwritten when we copy the kexec image. We piggyback on the |
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* "init_task" linker section here to statically allocate a stack. |
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* |
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* We could use a smaller stack if we don't care about anything using |
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* current, but that audit has not been performed. |
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*/ |
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static union thread_union kexec_stack __init_task_data = |
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{ }; |
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/* |
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* For similar reasons to the stack above, the kexecing CPU needs to be on a |
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* static PACA; we switch to kexec_paca. |
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*/ |
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struct paca_struct kexec_paca; |
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/* Our assembly helper, in misc_64.S */ |
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extern void kexec_sequence(void *newstack, unsigned long start, |
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void *image, void *control, |
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void (*clear_all)(void), |
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bool copy_with_mmu_off) __noreturn; |
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/* too late to fail here */ |
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void default_machine_kexec(struct kimage *image) |
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{ |
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bool copy_with_mmu_off; |
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/* prepare control code if any */ |
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/* |
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* If the kexec boot is the normal one, need to shutdown other cpus |
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* into our wait loop and quiesce interrupts. |
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* Otherwise, in the case of crashed mode (crashing_cpu >= 0), |
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* stopping other CPUs and collecting their pt_regs is done before |
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* using debugger IPI. |
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*/ |
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if (!kdump_in_progress()) |
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kexec_prepare_cpus(); |
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printk("kexec: Starting switchover sequence.\n"); |
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/* switch to a staticly allocated stack. Based on irq stack code. |
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* We setup preempt_count to avoid using VMX in memcpy. |
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* XXX: the task struct will likely be invalid once we do the copy! |
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*/ |
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current_thread_info()->flags = 0; |
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current_thread_info()->preempt_count = HARDIRQ_OFFSET; |
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/* We need a static PACA, too; copy this CPU's PACA over and switch to |
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* it. Also poison per_cpu_offset and NULL lppaca to catch anyone using |
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* non-static data. |
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*/ |
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memcpy(&kexec_paca, get_paca(), sizeof(struct paca_struct)); |
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kexec_paca.data_offset = 0xedeaddeadeeeeeeeUL; |
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#ifdef CONFIG_PPC_PSERIES |
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kexec_paca.lppaca_ptr = NULL; |
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#endif |
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if (is_secure_guest() && !(image->preserve_context || |
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image->type == KEXEC_TYPE_CRASH)) { |
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uv_unshare_all_pages(); |
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printk("kexec: Unshared all shared pages.\n"); |
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} |
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paca_ptrs[kexec_paca.paca_index] = &kexec_paca; |
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setup_paca(&kexec_paca); |
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/* |
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* The lppaca should be unregistered at this point so the HV won't |
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* touch it. In the case of a crash, none of the lppacas are |
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* unregistered so there is not much we can do about it here. |
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*/ |
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/* |
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* On Book3S, the copy must happen with the MMU off if we are either |
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* using Radix page tables or we are not in an LPAR since we can |
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* overwrite the page tables while copying. |
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* |
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* In an LPAR, we keep the MMU on otherwise we can't access beyond |
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* the RMA. On BookE there is no real MMU off mode, so we have to |
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* keep it enabled as well (but then we have bolted TLB entries). |
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*/ |
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#ifdef CONFIG_PPC_BOOK3E |
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copy_with_mmu_off = false; |
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#else |
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copy_with_mmu_off = radix_enabled() || |
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!(firmware_has_feature(FW_FEATURE_LPAR) || |
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firmware_has_feature(FW_FEATURE_PS3_LV1)); |
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#endif |
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/* Some things are best done in assembly. Finding globals with |
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* a toc is easier in C, so pass in what we can. |
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*/ |
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kexec_sequence(&kexec_stack, image->start, image, |
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page_address(image->control_code_page), |
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mmu_cleanup_all, copy_with_mmu_off); |
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/* NOTREACHED */ |
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} |
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#ifdef CONFIG_PPC_BOOK3S_64 |
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/* Values we need to export to the second kernel via the device tree. */ |
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static unsigned long htab_base; |
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static unsigned long htab_size; |
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static struct property htab_base_prop = { |
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.name = "linux,htab-base", |
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.length = sizeof(unsigned long), |
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.value = &htab_base, |
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}; |
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static struct property htab_size_prop = { |
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.name = "linux,htab-size", |
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.length = sizeof(unsigned long), |
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.value = &htab_size, |
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}; |
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static int __init export_htab_values(void) |
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{ |
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struct device_node *node; |
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/* On machines with no htab htab_address is NULL */ |
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if (!htab_address) |
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return -ENODEV; |
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node = of_find_node_by_path("/chosen"); |
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if (!node) |
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return -ENODEV; |
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/* remove any stale propertys so ours can be found */ |
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of_remove_property(node, of_find_property(node, htab_base_prop.name, NULL)); |
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of_remove_property(node, of_find_property(node, htab_size_prop.name, NULL)); |
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htab_base = cpu_to_be64(__pa(htab_address)); |
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of_add_property(node, &htab_base_prop); |
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htab_size = cpu_to_be64(htab_size_bytes); |
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of_add_property(node, &htab_size_prop); |
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of_node_put(node); |
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return 0; |
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} |
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late_initcall(export_htab_values); |
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#endif /* CONFIG_PPC_BOOK3S_64 */
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