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[S390] hibernate: Do real CPU swap at resume time

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Currently, when the physical resume CPU is not equal to the physical suspend
CPU, we swap the CPUs logically, by modifying the logical/physical CPU mapping.
This has two major drawbacks: First the change is visible from user space (e.g.
CPU sysfs files) and second it is hard to ensure that nowhere in the kernel
the physical CPU ID is stored before suspend.
To fix this, we now really swap the physical CPUs, if the resume CPU is not
the pysical suspend CPU. We restart the suspend CPU and stop the resume CPU
using SIGP restart and SIGP stop. If the suspend CPU is no longer available,
we write a message and load a disabled wait PSW.

Signed-off-by: Michael Holzheu <michael.holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Michael Holzheu
2009-09-22 22:58:53 +02:00
committed by Martin Schwidefsky
parent 68d1e5f08b
commit 1aaf179d04
5 changed files with 71 additions and 69 deletions
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36
arch/s390/kernel/smp.c
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@@ -1041,42 +1041,6 @@ out:
static SYSDEV_CLASS_ATTR(dispatching, 0644, dispatching_show,
dispatching_store);
/*
* If the resume kernel runs on another cpu than the suspended kernel,
* we have to switch the cpu IDs in the logical map.
*/
void smp_switch_boot_cpu_in_resume(u32 resume_phys_cpu_id,
struct _lowcore *suspend_lowcore)
{
int cpu, suspend_cpu_id, resume_cpu_id;
u32 suspend_phys_cpu_id;
suspend_phys_cpu_id = __cpu_logical_map[suspend_lowcore->cpu_nr];
suspend_cpu_id = suspend_lowcore->cpu_nr;
for_each_present_cpu(cpu) {
if (__cpu_logical_map[cpu] == resume_phys_cpu_id) {
resume_cpu_id = cpu;
goto found;
}
}
panic("Could not find resume cpu in logical map.\n");
found:
printk("Resume cpu ID: %i/%i\n", resume_phys_cpu_id, resume_cpu_id);
printk("Suspend cpu ID: %i/%i\n", suspend_phys_cpu_id, suspend_cpu_id);
__cpu_logical_map[resume_cpu_id] = suspend_phys_cpu_id;
__cpu_logical_map[suspend_cpu_id] = resume_phys_cpu_id;
lowcore_ptr[suspend_cpu_id]->cpu_addr = resume_phys_cpu_id;
}
u32 smp_get_phys_cpu_id(void)
{
return __cpu_logical_map[smp_processor_id()];
}
static int __init topology_init(void)
{
int cpu;