// 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/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 = (u64)(unsigned long)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 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_oldmem_kernel(buf_align, (void *) 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_BASE) goto fail; if (copy_oldmem_kernel(&addr, (void *)__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, (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