cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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os_info.c (4039B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * OS info memory interface
      4 *
      5 * Copyright IBM Corp. 2012
      6 * Author(s): Michael Holzheu <holzheu@linux.vnet.ibm.com>
      7 */
      8
      9#define KMSG_COMPONENT "os_info"
     10#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
     11
     12#include <linux/crash_dump.h>
     13#include <linux/kernel.h>
     14#include <linux/slab.h>
     15#include <asm/checksum.h>
     16#include <asm/lowcore.h>
     17#include <asm/os_info.h>
     18#include <asm/asm-offsets.h>
     19
     20/*
     21 * OS info structure has to be page aligned
     22 */
     23static struct os_info os_info __page_aligned_data;
     24
     25/*
     26 * Compute checksum over OS info structure
     27 */
     28u32 os_info_csum(struct os_info *os_info)
     29{
     30	int size = sizeof(*os_info) - offsetof(struct os_info, version_major);
     31	return (__force u32)csum_partial(&os_info->version_major, size, 0);
     32}
     33
     34/*
     35 * Add crashkernel info to OS info and update checksum
     36 */
     37void os_info_crashkernel_add(unsigned long base, unsigned long size)
     38{
     39	os_info.crashkernel_addr = (u64)(unsigned long)base;
     40	os_info.crashkernel_size = (u64)(unsigned long)size;
     41	os_info.csum = os_info_csum(&os_info);
     42}
     43
     44/*
     45 * Add OS info entry and update checksum
     46 */
     47void os_info_entry_add(int nr, void *ptr, u64 size)
     48{
     49	os_info.entry[nr].addr = __pa(ptr);
     50	os_info.entry[nr].size = size;
     51	os_info.entry[nr].csum = (__force u32)csum_partial(ptr, size, 0);
     52	os_info.csum = os_info_csum(&os_info);
     53}
     54
     55/*
     56 * Initialize OS info structure and set lowcore pointer
     57 */
     58void __init os_info_init(void)
     59{
     60	void *ptr = &os_info;
     61
     62	os_info.version_major = OS_INFO_VERSION_MAJOR;
     63	os_info.version_minor = OS_INFO_VERSION_MINOR;
     64	os_info.magic = OS_INFO_MAGIC;
     65	os_info.csum = os_info_csum(&os_info);
     66	put_abs_lowcore(os_info, __pa(ptr));
     67}
     68
     69#ifdef CONFIG_CRASH_DUMP
     70
     71static struct os_info *os_info_old;
     72
     73/*
     74 * Allocate and copy OS info entry from oldmem
     75 */
     76static void os_info_old_alloc(int nr, int align)
     77{
     78	unsigned long addr, size = 0;
     79	char *buf, *buf_align, *msg;
     80	u32 csum;
     81
     82	addr = os_info_old->entry[nr].addr;
     83	if (!addr) {
     84		msg = "not available";
     85		goto fail;
     86	}
     87	size = os_info_old->entry[nr].size;
     88	buf = kmalloc(size + align - 1, GFP_KERNEL);
     89	if (!buf) {
     90		msg = "alloc failed";
     91		goto fail;
     92	}
     93	buf_align = PTR_ALIGN(buf, align);
     94	if (copy_oldmem_kernel(buf_align, addr, size)) {
     95		msg = "copy failed";
     96		goto fail_free;
     97	}
     98	csum = (__force u32)csum_partial(buf_align, size, 0);
     99	if (csum != os_info_old->entry[nr].csum) {
    100		msg = "checksum failed";
    101		goto fail_free;
    102	}
    103	os_info_old->entry[nr].addr = (u64)(unsigned long)buf_align;
    104	msg = "copied";
    105	goto out;
    106fail_free:
    107	kfree(buf);
    108fail:
    109	os_info_old->entry[nr].addr = 0;
    110out:
    111	pr_info("entry %i: %s (addr=0x%lx size=%lu)\n",
    112		nr, msg, addr, size);
    113}
    114
    115/*
    116 * Initialize os info and os info entries from oldmem
    117 */
    118static void os_info_old_init(void)
    119{
    120	static int os_info_init;
    121	unsigned long addr;
    122
    123	if (os_info_init)
    124		return;
    125	if (!oldmem_data.start)
    126		goto fail;
    127	if (copy_oldmem_kernel(&addr, __LC_OS_INFO, sizeof(addr)))
    128		goto fail;
    129	if (addr == 0 || addr % PAGE_SIZE)
    130		goto fail;
    131	os_info_old = kzalloc(sizeof(*os_info_old), GFP_KERNEL);
    132	if (!os_info_old)
    133		goto fail;
    134	if (copy_oldmem_kernel(os_info_old, addr, sizeof(*os_info_old)))
    135		goto fail_free;
    136	if (os_info_old->magic != OS_INFO_MAGIC)
    137		goto fail_free;
    138	if (os_info_old->csum != os_info_csum(os_info_old))
    139		goto fail_free;
    140	if (os_info_old->version_major > OS_INFO_VERSION_MAJOR)
    141		goto fail_free;
    142	os_info_old_alloc(OS_INFO_VMCOREINFO, 1);
    143	os_info_old_alloc(OS_INFO_REIPL_BLOCK, 1);
    144	pr_info("crashkernel: addr=0x%lx size=%lu\n",
    145		(unsigned long) os_info_old->crashkernel_addr,
    146		(unsigned long) os_info_old->crashkernel_size);
    147	os_info_init = 1;
    148	return;
    149fail_free:
    150	kfree(os_info_old);
    151fail:
    152	os_info_init = 1;
    153	os_info_old = NULL;
    154}
    155
    156/*
    157 * Return pointer to os infor entry and its size
    158 */
    159void *os_info_old_entry(int nr, unsigned long *size)
    160{
    161	os_info_old_init();
    162
    163	if (!os_info_old)
    164		return NULL;
    165	if (!os_info_old->entry[nr].addr)
    166		return NULL;
    167	*size = (unsigned long) os_info_old->entry[nr].size;
    168	return (void *)(unsigned long)os_info_old->entry[nr].addr;
    169}
    170#endif