![Phileas Fogg](/assets/img/avatar_default.png)
Disable hard IRQ before kexec a new kernel image. Not doing it can result in corrupted data in the memory segments reserved for the new kernel. Signed-off-by: Phileas Fogg <phileas-fogg@mail.ru> CC: <stable@vger.kernel.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
410 lines
11 KiB
C
410 lines
11 KiB
C
/*
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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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* This source code is licensed under the GNU General Public License,
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* Version 2. See the file COPYING for more details.
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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 <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/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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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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if (!ppc_md.hpte_clear_all)
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return -ENOENT;
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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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/*
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* For non-LPAR, we absolutely can not overwrite the mmu hash
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* table, since we are still using the bolted entries in it to
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* do the copy. Check that here.
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*
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* It is safe if the end is below the start of the blocked
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* region (end <= low), or if the beginning is after the
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* end of the blocked region (begin >= high). Use the
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* boolean identity !(a || b) === (!a && !b).
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*/
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if (htab_address) {
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low = __pa(htab_address);
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high = low + htab_size_bytes;
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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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/* 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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#define IND_FLAGS (IND_DESTINATION | IND_INDIRECTION | IND_DONE | IND_SOURCE)
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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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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[].cpu_start was written) and
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* get into a peculiar state. If the platform supports
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* smp_ops->take_timebase(), the secondary CPU will probably be spinning
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* in there. If not (i.e. pseries), the secondary will continue on and
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* try to online itself/idle/etc. If it survives that, we need to find
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* these possible-but-not-online-but-should-be CPUs and chaperone them
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* into 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[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[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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cpu_up(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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/* 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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/*
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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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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 kexec_stub.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)) __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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/* 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 (crashing_cpu == -1)
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kexec_prepare_cpus();
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pr_debug("kexec: Starting switchover sequence.\n");
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/* switch to a staticly allocated stack. Based on irq stack code.
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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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kexec_stack.thread_info.task = current_thread_info()->task;
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kexec_stack.thread_info.flags = 0;
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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 to catch anyone using non-static
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* 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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paca = (struct paca_struct *)RELOC_HIDE(&kexec_paca, 0) -
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kexec_paca.paca_index;
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setup_paca(&kexec_paca);
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/* XXX: If anyone does 'dynamic lppacas' this will also need to be
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* switched to a static version!
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*/
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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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ppc_md.hpte_clear_all);
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/* NOTREACHED */
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}
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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 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_bytes,
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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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struct property *prop;
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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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prop = of_find_property(node, htab_base_prop.name, NULL);
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if (prop)
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of_remove_property(node, prop);
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prop = of_find_property(node, htab_size_prop.name, NULL);
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if (prop)
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of_remove_property(node, prop);
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htab_base = __pa(htab_address);
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of_add_property(node, &htab_base_prop);
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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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