linux/arch/s390/kernel/os_info.c
Heiko Carstens fbe765680d s390/smp: make absolute lowcore / cpu restart parameter accesses more robust
Setting the cpu restart parameters is done in three different fashions:
- directly setting the four parameters individually
- copying the four parameters with memcpy (using 4 * sizeof(long))
- copying the four parameters using a private structure

In addition code in entry*.S relies on a certain order of the restart
members of struct _lowcore.

Make all of this more robust to future changes by adding a
mem_absolute_assign(dest, val) define, which assigns val to dest
using absolute addressing mode. Also the load multiple instructions
in entry*.S have been split into separate load instruction so the
order of the struct _lowcore members doesn't matter anymore.

In addition move the prototypes of memcpy_real/absolute from uaccess.h
to processor.h. These memcpy* variants are not related to uaccess at all.
string.h doesn't seem to match as well, so lets use processor.h.

Also replace the eight byte array in struct _lowcore which represents a
misaliged u64 with a u64. The compiler will always create code that
handles the misaligned u64 correctly.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2012-06-14 09:09:02 +02:00

168 lines
3.9 KiB
C

/*
* OS info memory interface
*
* Copyright IBM Corp. 2012
* Author(s): Michael Holzheu <holzheu@linux.vnet.ibm.com>
*/
#define KMSG_COMPONENT "os_info"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/crash_dump.h>
#include <linux/kernel.h>
#include <asm/checksum.h>
#include <asm/lowcore.h>
#include <asm/os_info.h>
/*
* OS info structure has to be page aligned
*/
static struct os_info os_info __page_aligned_data;
/*
* Compute checksum over OS info structure
*/
u32 os_info_csum(struct os_info *os_info)
{
int size = sizeof(*os_info) - offsetof(struct os_info, version_major);
return csum_partial(&os_info->version_major, size, 0);
}
/*
* Add crashkernel info to OS info and update checksum
*/
void os_info_crashkernel_add(unsigned long base, unsigned long size)
{
os_info.crashkernel_addr = (u64)(unsigned long)base;
os_info.crashkernel_size = (u64)(unsigned long)size;
os_info.csum = os_info_csum(&os_info);
}
/*
* Add OS info entry and update checksum
*/
void os_info_entry_add(int nr, void *ptr, u64 size)
{
os_info.entry[nr].addr = (u64)(unsigned long)ptr;
os_info.entry[nr].size = size;
os_info.entry[nr].csum = csum_partial(ptr, size, 0);
os_info.csum = os_info_csum(&os_info);
}
/*
* Initialize OS info struture and set lowcore pointer
*/
void __init os_info_init(void)
{
void *ptr = &os_info;
os_info.version_major = OS_INFO_VERSION_MAJOR;
os_info.version_minor = OS_INFO_VERSION_MINOR;
os_info.magic = OS_INFO_MAGIC;
os_info.csum = os_info_csum(&os_info);
mem_assign_absolute(S390_lowcore.os_info, (unsigned long) ptr);
}
#ifdef CONFIG_CRASH_DUMP
static struct os_info *os_info_old;
/*
* Allocate and copy OS info entry from oldmem
*/
static void os_info_old_alloc(int nr, int align)
{
unsigned long addr, size = 0;
char *buf, *buf_align, *msg;
u32 csum;
addr = os_info_old->entry[nr].addr;
if (!addr) {
msg = "not available";
goto fail;
}
size = os_info_old->entry[nr].size;
buf = kmalloc(size + align - 1, GFP_KERNEL);
if (!buf) {
msg = "alloc failed";
goto fail;
}
buf_align = PTR_ALIGN(buf, align);
if (copy_from_oldmem(buf_align, (void *) addr, size)) {
msg = "copy failed";
goto fail_free;
}
csum = csum_partial(buf_align, size, 0);
if (csum != os_info_old->entry[nr].csum) {
msg = "checksum failed";
goto fail_free;
}
os_info_old->entry[nr].addr = (u64)(unsigned long)buf_align;
msg = "copied";
goto out;
fail_free:
kfree(buf);
fail:
os_info_old->entry[nr].addr = 0;
out:
pr_info("entry %i: %s (addr=0x%lx size=%lu)\n",
nr, msg, addr, size);
}
/*
* Initialize os info and os info entries from oldmem
*/
static void os_info_old_init(void)
{
static int os_info_init;
unsigned long addr;
if (os_info_init)
return;
if (!OLDMEM_BASE)
goto fail;
if (copy_from_oldmem(&addr, &S390_lowcore.os_info, sizeof(addr)))
goto fail;
if (addr == 0 || addr % PAGE_SIZE)
goto fail;
os_info_old = kzalloc(sizeof(*os_info_old), GFP_KERNEL);
if (!os_info_old)
goto fail;
if (copy_from_oldmem(os_info_old, (void *) addr, sizeof(*os_info_old)))
goto fail_free;
if (os_info_old->magic != OS_INFO_MAGIC)
goto fail_free;
if (os_info_old->csum != os_info_csum(os_info_old))
goto fail_free;
if (os_info_old->version_major > OS_INFO_VERSION_MAJOR)
goto fail_free;
os_info_old_alloc(OS_INFO_VMCOREINFO, 1);
os_info_old_alloc(OS_INFO_REIPL_BLOCK, 1);
pr_info("crashkernel: addr=0x%lx size=%lu\n",
(unsigned long) os_info_old->crashkernel_addr,
(unsigned long) os_info_old->crashkernel_size);
os_info_init = 1;
return;
fail_free:
kfree(os_info_old);
fail:
os_info_init = 1;
os_info_old = NULL;
}
/*
* Return pointer to os infor entry and its size
*/
void *os_info_old_entry(int nr, unsigned long *size)
{
os_info_old_init();
if (!os_info_old)
return NULL;
if (!os_info_old->entry[nr].addr)
return NULL;
*size = (unsigned long) os_info_old->entry[nr].size;
return (void *)(unsigned long)os_info_old->entry[nr].addr;
}
#endif