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https://github.com/edk2-porting/linux-next.git
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19ab428f4b
Add comments to machine_shutdown()/halt()/power_off()/restart() that describe their purpose and/or requirements re: CPUs being active/not. In machine_shutdown(), replace the call to smp_send_stop() with a call to disable_nonboot_cpus(). This completely disables all but one CPU, thus satisfying the requirement that only a single CPU be active for kexec. Adjust Kconfig dependencies for this change. In machine_halt()/power_off()/restart(), call smp_send_stop() directly, rather than via machine_shutdown(); these functions don't need to completely de-activate all CPUs using hotplug, but rather just quiesce them. Remove smp_kill_cpus(), and its call from smp_send_stop(). smp_kill_cpus() was indirectly calling smp_ops.cpu_kill() without calling smp_ops.cpu_die() on the target CPUs first. At least some implementations of smp_ops had issues with this; it caused cpu_kill() to hang on Tegra, for example. Since smp_send_stop() is only used for shutdown, halt, and power-off, there is no need to attempt any kind of CPU hotplug here. Adjust Kconfig to reflect that machine_shutdown() (and hence kexec) relies upon disable_nonboot_cpus(). However, this alone doesn't guarantee that hotplug will work, or even that hotplug is implemented for a particular piece of HW that a multi-platform zImage runs on. Hence, add error-checking to machine_kexec() to determine whether it did work. Suggested-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Stephen Warren <swarren@nvidia.com> Acked-by: Will Deacon <will.deacon@arm.com> Tested-by: Zhangfei Gao <zhangfei.gao@gmail.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
171 lines
4.1 KiB
C
171 lines
4.1 KiB
C
/*
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* machine_kexec.c - handle transition of Linux booting another kernel
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*/
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#include <linux/mm.h>
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#include <linux/kexec.h>
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#include <linux/delay.h>
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#include <linux/reboot.h>
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#include <linux/io.h>
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#include <linux/irq.h>
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#include <linux/memblock.h>
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#include <asm/pgtable.h>
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#include <linux/of_fdt.h>
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#include <asm/pgalloc.h>
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#include <asm/mmu_context.h>
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#include <asm/cacheflush.h>
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#include <asm/mach-types.h>
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#include <asm/system_misc.h>
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extern const unsigned char relocate_new_kernel[];
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extern const unsigned int relocate_new_kernel_size;
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extern unsigned long kexec_start_address;
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extern unsigned long kexec_indirection_page;
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extern unsigned long kexec_mach_type;
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extern unsigned long kexec_boot_atags;
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static atomic_t waiting_for_crash_ipi;
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/*
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* Provide a dummy crash_notes definition while crash dump arrives to arm.
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* This prevents breakage of crash_notes attribute in kernel/ksysfs.c.
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*/
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int machine_kexec_prepare(struct kimage *image)
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{
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struct kexec_segment *current_segment;
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__be32 header;
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int i, err;
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/*
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* No segment at default ATAGs address. try to locate
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* a dtb using magic.
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*/
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for (i = 0; i < image->nr_segments; i++) {
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current_segment = &image->segment[i];
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if (!memblock_is_region_memory(current_segment->mem,
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current_segment->memsz))
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return -EINVAL;
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err = get_user(header, (__be32*)current_segment->buf);
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if (err)
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return err;
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if (be32_to_cpu(header) == OF_DT_HEADER)
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kexec_boot_atags = current_segment->mem;
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}
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return 0;
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}
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void machine_kexec_cleanup(struct kimage *image)
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{
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}
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void machine_crash_nonpanic_core(void *unused)
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{
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struct pt_regs regs;
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crash_setup_regs(®s, NULL);
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printk(KERN_DEBUG "CPU %u will stop doing anything useful since another CPU has crashed\n",
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smp_processor_id());
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crash_save_cpu(®s, smp_processor_id());
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flush_cache_all();
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atomic_dec(&waiting_for_crash_ipi);
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while (1)
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cpu_relax();
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}
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static void machine_kexec_mask_interrupts(void)
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{
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unsigned int i;
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struct irq_desc *desc;
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for_each_irq_desc(i, desc) {
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struct irq_chip *chip;
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chip = irq_desc_get_chip(desc);
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if (!chip)
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continue;
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if (chip->irq_eoi && irqd_irq_inprogress(&desc->irq_data))
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chip->irq_eoi(&desc->irq_data);
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if (chip->irq_mask)
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chip->irq_mask(&desc->irq_data);
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if (chip->irq_disable && !irqd_irq_disabled(&desc->irq_data))
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chip->irq_disable(&desc->irq_data);
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}
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}
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void machine_crash_shutdown(struct pt_regs *regs)
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{
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unsigned long msecs;
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local_irq_disable();
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atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
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smp_call_function(machine_crash_nonpanic_core, NULL, false);
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msecs = 1000; /* Wait at most a second for the other cpus to stop */
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while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
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mdelay(1);
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msecs--;
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}
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if (atomic_read(&waiting_for_crash_ipi) > 0)
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printk(KERN_WARNING "Non-crashing CPUs did not react to IPI\n");
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crash_save_cpu(regs, smp_processor_id());
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machine_kexec_mask_interrupts();
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printk(KERN_INFO "Loading crashdump kernel...\n");
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}
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/*
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* Function pointer to optional machine-specific reinitialization
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*/
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void (*kexec_reinit)(void);
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void machine_kexec(struct kimage *image)
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{
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unsigned long page_list;
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unsigned long reboot_code_buffer_phys;
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void *reboot_code_buffer;
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if (num_online_cpus() > 1) {
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pr_err("kexec: error: multiple CPUs still online\n");
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return;
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}
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page_list = image->head & PAGE_MASK;
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/* we need both effective and real address here */
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reboot_code_buffer_phys =
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page_to_pfn(image->control_code_page) << PAGE_SHIFT;
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reboot_code_buffer = page_address(image->control_code_page);
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/* Prepare parameters for reboot_code_buffer*/
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kexec_start_address = image->start;
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kexec_indirection_page = page_list;
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kexec_mach_type = machine_arch_type;
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if (!kexec_boot_atags)
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kexec_boot_atags = image->start - KEXEC_ARM_ZIMAGE_OFFSET + KEXEC_ARM_ATAGS_OFFSET;
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/* copy our kernel relocation code to the control code page */
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memcpy(reboot_code_buffer,
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relocate_new_kernel, relocate_new_kernel_size);
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flush_icache_range((unsigned long) reboot_code_buffer,
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(unsigned long) reboot_code_buffer + KEXEC_CONTROL_PAGE_SIZE);
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printk(KERN_INFO "Bye!\n");
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if (kexec_reinit)
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kexec_reinit();
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soft_restart(reboot_code_buffer_phys);
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}
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