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// SPDX-License-Identifier: GPL-2.0
/*
* 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 <linux/slab.h>
#include <asm/checksum.h>
#include <asm/abs_lowcore.h>
#include <asm/os_info.h>
#include <asm/asm-offsets.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 (__force u32)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 = __pa(ptr);
os_info.entry[nr].size = size;
os_info.entry[nr].csum = (__force u32)csum_partial(ptr, size, 0);
os_info.csum = os_info_csum(&os_info);
}
/*
* Initialize OS info structure and set lowcore pointer
*/
void __init os_info_init(void)
{
struct lowcore *abs_lc;
unsigned long flags;
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);
abs_lc = get_abs_lowcore(&flags);
abs_lc->os_info = __pa(&os_info);
put_abs_lowcore(abs_lc, flags);
}
#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_oldmem_kernel(buf_align, addr, size)) {
msg = "copy failed";
goto fail_free;
}
csum = (__force u32)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_data.start)
goto fail;
if (copy_oldmem_kernel(&addr, __LC_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_oldmem_kernel(os_info_old, 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
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