linux-stable/arch/s390/hypfs/hypfs_diag0c.c
Gerald Schaefer a80313ff91 s390/kernel: introduce .dma sections
With a relocatable kernel that could reside at any place in memory, code
and data that has to stay below 2 GB needs special handling.

This patch introduces .dma sections for such text, data and ex_table.
The sections will be part of the decompressor kernel, so they will not
be relocated and stay below 2 GB. Their location is passed over to the
decompressed / relocated kernel via the .boot.preserved.data section.

The duald and aste for control register setup also need to stay below
2 GB, so move the setup code from arch/s390/kernel/head64.S to
arch/s390/boot/head.S. The duct and linkage_stack could reside above
2 GB, but their content has to be preserved for the decompresed kernel,
so they are also moved into the .dma section.

The start and end address of the .dma sections is added to vmcoreinfo,
for crash support, to help debugging in case the kernel crashed there.

Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Reviewed-by: Philipp Rudo <prudo@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2019-04-29 10:47:10 +02:00

125 lines
2.7 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Hypervisor filesystem for Linux on s390
*
* Diag 0C implementation
*
* Copyright IBM Corp. 2014
*/
#include <linux/slab.h>
#include <linux/cpu.h>
#include <asm/diag.h>
#include <asm/hypfs.h>
#include "hypfs.h"
#define DBFS_D0C_HDR_VERSION 0
/*
* Get hypfs_diag0c_entry from CPU vector and store diag0c data
*/
static void diag0c_fn(void *data)
{
diag_stat_inc(DIAG_STAT_X00C);
diag_dma_ops.diag0c(((void **) data)[smp_processor_id()]);
}
/*
* Allocate buffer and store diag 0c data
*/
static void *diag0c_store(unsigned int *count)
{
struct hypfs_diag0c_data *diag0c_data;
unsigned int cpu_count, cpu, i;
void **cpu_vec;
get_online_cpus();
cpu_count = num_online_cpus();
cpu_vec = kmalloc_array(num_possible_cpus(), sizeof(*cpu_vec),
GFP_KERNEL);
if (!cpu_vec)
goto fail_put_online_cpus;
/* Note: Diag 0c needs 8 byte alignment and real storage */
diag0c_data = kzalloc(struct_size(diag0c_data, entry, cpu_count),
GFP_KERNEL | GFP_DMA);
if (!diag0c_data)
goto fail_kfree_cpu_vec;
i = 0;
/* Fill CPU vector for each online CPU */
for_each_online_cpu(cpu) {
diag0c_data->entry[i].cpu = cpu;
cpu_vec[cpu] = &diag0c_data->entry[i++];
}
/* Collect data all CPUs */
on_each_cpu(diag0c_fn, cpu_vec, 1);
*count = cpu_count;
kfree(cpu_vec);
put_online_cpus();
return diag0c_data;
fail_kfree_cpu_vec:
kfree(cpu_vec);
fail_put_online_cpus:
put_online_cpus();
return ERR_PTR(-ENOMEM);
}
/*
* Hypfs DBFS callback: Free diag 0c data
*/
static void dbfs_diag0c_free(const void *data)
{
kfree(data);
}
/*
* Hypfs DBFS callback: Create diag 0c data
*/
static int dbfs_diag0c_create(void **data, void **data_free_ptr, size_t *size)
{
struct hypfs_diag0c_data *diag0c_data;
unsigned int count;
diag0c_data = diag0c_store(&count);
if (IS_ERR(diag0c_data))
return PTR_ERR(diag0c_data);
memset(&diag0c_data->hdr, 0, sizeof(diag0c_data->hdr));
get_tod_clock_ext(diag0c_data->hdr.tod_ext);
diag0c_data->hdr.len = count * sizeof(struct hypfs_diag0c_entry);
diag0c_data->hdr.version = DBFS_D0C_HDR_VERSION;
diag0c_data->hdr.count = count;
*data = diag0c_data;
*data_free_ptr = diag0c_data;
*size = diag0c_data->hdr.len + sizeof(struct hypfs_diag0c_hdr);
return 0;
}
/*
* Hypfs DBFS file structure
*/
static struct hypfs_dbfs_file dbfs_file_0c = {
.name = "diag_0c",
.data_create = dbfs_diag0c_create,
.data_free = dbfs_diag0c_free,
};
/*
* Initialize diag 0c interface for z/VM
*/
int __init hypfs_diag0c_init(void)
{
if (!MACHINE_IS_VM)
return 0;
hypfs_dbfs_create_file(&dbfs_file_0c);
return 0;
}
/*
* Shutdown diag 0c interface for z/VM
*/
void hypfs_diag0c_exit(void)
{
if (!MACHINE_IS_VM)
return;
hypfs_dbfs_remove_file(&dbfs_file_0c);
}