1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Hypervisor filesystem for Linux on s390. z/VM implementation. 4 * 5 * Copyright IBM Corp. 2006 6 * Author(s): Michael Holzheu <holzheu@de.ibm.com> 7 */ 8 9 #include <linux/types.h> 10 #include <linux/errno.h> 11 #include <linux/string.h> 12 #include <linux/vmalloc.h> 13 #include <asm/extable.h> 14 #include <asm/diag.h> 15 #include <asm/ebcdic.h> 16 #include <asm/timex.h> 17 #include "hypfs_vm.h" 18 #include "hypfs.h" 19 20 #define DBFS_D2FC_HDR_VERSION 0 21 22 static char local_guest[] = " "; 23 static char all_guests[] = "* "; 24 static char *all_groups = all_guests; 25 char *diag2fc_guest_query; 26 27 static int diag2fc(int size, char* query, void *addr) 28 { 29 unsigned long residual_cnt; 30 unsigned long rc; 31 struct diag2fc_parm_list parm_list; 32 33 memcpy(parm_list.userid, query, DIAG2FC_NAME_LEN); 34 ASCEBC(parm_list.userid, DIAG2FC_NAME_LEN); 35 memcpy(parm_list.aci_grp, all_groups, DIAG2FC_NAME_LEN); 36 ASCEBC(parm_list.aci_grp, DIAG2FC_NAME_LEN); 37 parm_list.addr = (unsigned long)addr; 38 parm_list.size = size; 39 parm_list.fmt = 0x02; 40 rc = -1; 41 42 diag_stat_inc(DIAG_STAT_X2FC); 43 asm volatile( 44 " diag %0,%1,0x2fc\n" 45 "0: nopr %%r7\n" 46 EX_TABLE(0b,0b) 47 : "=d" (residual_cnt), "+d" (rc) : "0" (&parm_list) : "memory"); 48 49 if ((rc != 0 ) && (rc != -2)) 50 return rc; 51 else 52 return -residual_cnt; 53 } 54 55 /* 56 * Allocate buffer for "query" and store diag 2fc at "offset" 57 */ 58 void *diag2fc_store(char *query, unsigned int *count, int offset) 59 { 60 void *data; 61 int size; 62 63 do { 64 size = diag2fc(0, query, NULL); 65 if (size < 0) 66 return ERR_PTR(-EACCES); 67 data = vmalloc(size + offset); 68 if (!data) 69 return ERR_PTR(-ENOMEM); 70 if (diag2fc(size, query, data + offset) == 0) 71 break; 72 vfree(data); 73 } while (1); 74 *count = (size / sizeof(struct diag2fc_data)); 75 76 return data; 77 } 78 79 void diag2fc_free(const void *data) 80 { 81 vfree(data); 82 } 83 84 struct dbfs_d2fc_hdr { 85 u64 len; /* Length of d2fc buffer without header */ 86 u16 version; /* Version of header */ 87 union tod_clock tod_ext; /* TOD clock for d2fc */ 88 u64 count; /* Number of VM guests in d2fc buffer */ 89 char reserved[30]; 90 } __attribute__ ((packed)); 91 92 struct dbfs_d2fc { 93 struct dbfs_d2fc_hdr hdr; /* 64 byte header */ 94 char buf[]; /* d2fc buffer */ 95 } __attribute__ ((packed)); 96 97 static int dbfs_diag2fc_create(void **data, void **data_free_ptr, size_t *size) 98 { 99 struct dbfs_d2fc *d2fc; 100 unsigned int count; 101 102 d2fc = diag2fc_store(diag2fc_guest_query, &count, sizeof(d2fc->hdr)); 103 if (IS_ERR(d2fc)) 104 return PTR_ERR(d2fc); 105 store_tod_clock_ext(&d2fc->hdr.tod_ext); 106 d2fc->hdr.len = count * sizeof(struct diag2fc_data); 107 d2fc->hdr.version = DBFS_D2FC_HDR_VERSION; 108 d2fc->hdr.count = count; 109 memset(&d2fc->hdr.reserved, 0, sizeof(d2fc->hdr.reserved)); 110 *data = d2fc; 111 *data_free_ptr = d2fc; 112 *size = d2fc->hdr.len + sizeof(struct dbfs_d2fc_hdr); 113 return 0; 114 } 115 116 static struct hypfs_dbfs_file dbfs_file_2fc = { 117 .name = "diag_2fc", 118 .data_create = dbfs_diag2fc_create, 119 .data_free = diag2fc_free, 120 }; 121 122 int hypfs_vm_init(void) 123 { 124 if (!MACHINE_IS_VM) 125 return 0; 126 if (diag2fc(0, all_guests, NULL) > 0) 127 diag2fc_guest_query = all_guests; 128 else if (diag2fc(0, local_guest, NULL) > 0) 129 diag2fc_guest_query = local_guest; 130 else 131 return -EACCES; 132 hypfs_dbfs_create_file(&dbfs_file_2fc); 133 return 0; 134 } 135 136 void hypfs_vm_exit(void) 137 { 138 if (!MACHINE_IS_VM) 139 return; 140 hypfs_dbfs_remove_file(&dbfs_file_2fc); 141 } 142