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/machine.h> 15 #include <asm/diag.h> 16 #include <asm/ebcdic.h> 17 #include <asm/timex.h> 18 #include "hypfs_vm.h" 19 #include "hypfs.h" 20 21 #define DBFS_D2FC_HDR_VERSION 0 22 23 static char local_guest[] = " "; 24 static char all_guests[] = "* "; 25 static char *all_groups = all_guests; 26 char *diag2fc_guest_query; 27 28 static int diag2fc(int size, char* query, void *addr) 29 { 30 unsigned long residual_cnt; 31 unsigned long rc; 32 struct diag2fc_parm_list parm_list; 33 34 memcpy(parm_list.userid, query, DIAG2FC_NAME_LEN); 35 ASCEBC(parm_list.userid, DIAG2FC_NAME_LEN); 36 memcpy(parm_list.aci_grp, all_groups, DIAG2FC_NAME_LEN); 37 ASCEBC(parm_list.aci_grp, DIAG2FC_NAME_LEN); 38 parm_list.addr = (unsigned long)addr; 39 parm_list.size = size; 40 parm_list.fmt = 0x02; 41 rc = -1; 42 43 diag_stat_inc(DIAG_STAT_X2FC); 44 asm volatile( 45 " diag %0,%1,0x2fc\n" 46 "0: nopr %%r7\n" 47 EX_TABLE(0b,0b) 48 : "=d" (residual_cnt), "+d" (rc) : "0" (&parm_list) : "memory"); 49 50 if ((rc != 0 ) && (rc != -2)) 51 return rc; 52 else 53 return -residual_cnt; 54 } 55 56 /* 57 * Allocate buffer for "query" and store diag 2fc at "offset" 58 */ 59 void *diag2fc_store(char *query, unsigned int *count, int offset) 60 { 61 void *data; 62 int size; 63 64 do { 65 size = diag2fc(0, query, NULL); 66 if (size < 0) 67 return ERR_PTR(-EACCES); 68 data = vmalloc(size + offset); 69 if (!data) 70 return ERR_PTR(-ENOMEM); 71 if (diag2fc(size, query, data + offset) == 0) 72 break; 73 vfree(data); 74 } while (1); 75 *count = (size / sizeof(struct diag2fc_data)); 76 77 return data; 78 } 79 80 void diag2fc_free(const void *data) 81 { 82 vfree(data); 83 } 84 85 struct dbfs_d2fc_hdr { 86 u64 len; /* Length of d2fc buffer without header */ 87 u16 version; /* Version of header */ 88 union tod_clock tod_ext; /* TOD clock for d2fc */ 89 u64 count; /* Number of VM guests in d2fc buffer */ 90 char reserved[30]; 91 } __attribute__ ((packed)); 92 93 struct dbfs_d2fc { 94 struct dbfs_d2fc_hdr hdr; /* 64 byte header */ 95 char buf[]; /* d2fc buffer */ 96 } __attribute__ ((packed)); 97 98 static int dbfs_diag2fc_create(void **data, void **data_free_ptr, size_t *size) 99 { 100 struct dbfs_d2fc *d2fc; 101 unsigned int count; 102 103 d2fc = diag2fc_store(diag2fc_guest_query, &count, sizeof(d2fc->hdr)); 104 if (IS_ERR(d2fc)) 105 return PTR_ERR(d2fc); 106 store_tod_clock_ext(&d2fc->hdr.tod_ext); 107 d2fc->hdr.len = count * sizeof(struct diag2fc_data); 108 d2fc->hdr.version = DBFS_D2FC_HDR_VERSION; 109 d2fc->hdr.count = count; 110 memset(&d2fc->hdr.reserved, 0, sizeof(d2fc->hdr.reserved)); 111 *data = d2fc; 112 *data_free_ptr = d2fc; 113 *size = d2fc->hdr.len + sizeof(struct dbfs_d2fc_hdr); 114 return 0; 115 } 116 117 static struct hypfs_dbfs_file dbfs_file_2fc = { 118 .name = "diag_2fc", 119 .data_create = dbfs_diag2fc_create, 120 .data_free = diag2fc_free, 121 }; 122 123 int hypfs_vm_init(void) 124 { 125 if (!machine_is_vm()) 126 return 0; 127 if (diag2fc(0, all_guests, NULL) > 0) 128 diag2fc_guest_query = all_guests; 129 else if (diag2fc(0, local_guest, NULL) > 0) 130 diag2fc_guest_query = local_guest; 131 else 132 return -EACCES; 133 hypfs_dbfs_create_file(&dbfs_file_2fc); 134 return 0; 135 } 136 137 void hypfs_vm_exit(void) 138 { 139 if (!machine_is_vm()) 140 return; 141 hypfs_dbfs_remove_file(&dbfs_file_2fc); 142 } 143