osfmk/i386/ucode.c

   1 /*
   2  * Copyright (c) 2017 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*
  29  *  ucode.c
  30  *
  31  *  Microcode updater interface sysctl
  32  */
  33
  34 #include <kern/locks.h>
  35 #include <i386/ucode.h>
  36 #include <sys/errno.h>
  37 #include <i386/proc_reg.h>
  38 #include <i386/cpuid.h>
  39 #include <vm/vm_kern.h>
  40 #include <i386/mp.h>                    // mp_broadcast
  41 #include <i386/fpu.h>
  42 #include <machine/cpu_number.h> // cpu_number
  43 #include <pexpert/pexpert.h>  // boot-args
  44
  45 #define IA32_BIOS_UPDT_TRIG (0x79) /* microcode update trigger MSR */
  46
  47 struct intel_ucupdate *global_update = NULL;
  48
  49 /* Exceute the actual update! */
  50 static void
  51 update_microcode(void)
  52 {
  53         /* SDM Example 9-8 code shows that we load the
  54          * address of the UpdateData within the microcode blob,
  55          * not the address of the header.
  56          */
  57         wrmsr64(IA32_BIOS_UPDT_TRIG, (uint64_t)(uintptr_t)&global_update->data);
  58 }
  59
  60 /* locks */
  61 static lck_grp_attr_t *ucode_slock_grp_attr = NULL;
  62 static lck_grp_t *ucode_slock_grp = NULL;
  63 static lck_attr_t *ucode_slock_attr = NULL;
  64 static lck_spin_t *ucode_slock = NULL;
  65
  66 static kern_return_t
  67 register_locks(void)
  68 {
  69         /* already allocated? */
  70         if (ucode_slock_grp_attr && ucode_slock_grp && ucode_slock_attr && ucode_slock)
  71                 return KERN_SUCCESS;
  72
  73         /* allocate lock group attribute and group */
  74         if (!(ucode_slock_grp_attr = lck_grp_attr_alloc_init()))
  75                 goto nomem_out;
  76
  77         lck_grp_attr_setstat(ucode_slock_grp_attr);
  78
  79         if (!(ucode_slock_grp = lck_grp_alloc_init("uccode_lock", ucode_slock_grp_attr)))
  80                 goto nomem_out;
  81
  82         /* Allocate lock attribute */
  83         if (!(ucode_slock_attr = lck_attr_alloc_init()))
  84                 goto nomem_out;
  85
  86         /* Allocate the spin lock */
  87         /* We keep one global spin-lock. We could have one per update
  88          * request... but srsly, why would you update microcode like that?
  89          */
  90         if (!(ucode_slock = lck_spin_alloc_init(ucode_slock_grp, ucode_slock_attr)))
  91                 goto nomem_out;
  92
  93         return KERN_SUCCESS;
  94
  95 nomem_out:
  96         /* clean up */
  97         if (ucode_slock)
  98                 lck_spin_free(ucode_slock, ucode_slock_grp);
  99         if (ucode_slock_attr)
 100                 lck_attr_free(ucode_slock_attr);
 101         if (ucode_slock_grp)
 102                 lck_grp_free(ucode_slock_grp);
 103         if (ucode_slock_grp_attr)
 104                 lck_grp_attr_free(ucode_slock_grp_attr);
 105
 106         return KERN_NO_SPACE;
 107 }
 108
 109 /* Copy in an update */
 110 static int
 111 copyin_update(uint64_t inaddr)
 112 {
 113         struct intel_ucupdate update_header;
 114         struct intel_ucupdate *update;
 115         vm_size_t size;
 116         kern_return_t ret;
 117         int error;
 118
 119         /* Copy in enough header to peek at the size */
 120         error = copyin((user_addr_t)inaddr, (void *)&update_header, sizeof(update_header));
 121         if (error)
 122                 return error;
 123
 124         /* Get the actual, alleged size */
 125         size = update_header.total_size;
 126
 127         /* huge bogus piece of data that somehow made it through? */
 128         if (size >= 1024 * 1024)
 129                 return ENOMEM;
 130
 131         /* Old microcodes? */
 132         if (size == 0)
 133                 size = 2048; /* default update size; see SDM */
 134
 135         /*
 136          * create the buffer for the update
 137          * It need only be aligned to 16-bytes, according to the SDM.
 138          * This also wires it down
 139          */
 140         ret = kmem_alloc_kobject(kernel_map, (vm_offset_t *)&update, size, VM_KERN_MEMORY_OSFMK);
 141         if (ret != KERN_SUCCESS)
 142                 return ENOMEM;
 143
 144         /* Copy it in */
 145         error = copyin((user_addr_t)inaddr, (void*)update, size);
 146         if (error) {
 147                 kmem_free(kernel_map, (vm_offset_t)update, size);
 148                 return error;
 149         }
 150
 151         global_update = update;
 152         return 0;
 153 }
 154
 155 /*
 156  * This is called once by every CPU on a wake from sleep/hibernate
 157  * and is meant to re-apply a microcode update that got lost
 158  * by sleeping.
 159  */
 160 void
 161 ucode_update_wake()
 162 {
 163         if (global_update) {
 164                 kprintf("ucode: Re-applying update after wake (CPU #%d)\n", cpu_number());
 165                 update_microcode();
 166 #if DEBUG
 167         } else {
 168                 kprintf("ucode: No update to apply (CPU #%d)\n", cpu_number());
 169 #endif
 170         }
 171 }
 172
 173 static void
 174 cpu_update(__unused void *arg)
 175 {
 176         /* grab the lock */
 177         lck_spin_lock(ucode_slock);
 178
 179         /* execute the update */
 180         update_microcode();
 181
 182         /* release the lock */
 183         lck_spin_unlock(ucode_slock);
 184 }
 185
 186 static void
 187 ucode_cpuid_set_info(void)
 188 {
 189         uint64_t saved_xcr0, dest_xcr0;
 190         int need_xcr0_restore = 0;
 191         boolean_t intrs_enabled = ml_set_interrupts_enabled(FALSE);
 192
 193         /*
 194          * Before we cache the CPUID information, we must configure XCR0 with the maximal set of
 195          * features to ensure the save area returned in the xsave leaf is correctly-sized.
 196          *
 197          * Since we are guaranteed that init_fpu() has already happened, we can use state
 198          * variables set there that were already predicated on the presence of explicit
 199          * boot-args enables/disables.
 200          */
 201
 202         if (fpu_capability == AVX512 || fpu_capability == AVX) {
 203                 saved_xcr0 = xgetbv(XCR0);
 204                 dest_xcr0 = (fpu_capability == AVX512) ? AVX512_XMASK : AVX_XMASK;
 205                 assert((get_cr4() & CR4_OSXSAVE) != 0);
 206                 if (saved_xcr0 != dest_xcr0) {
 207                         need_xcr0_restore = 1;
 208                         xsetbv(dest_xcr0 >> 32, dest_xcr0 & 0xFFFFFFFFUL);
 209                 }
 210         }
 211
 212         cpuid_set_info();
 213
 214         if (need_xcr0_restore) {
 215                 xsetbv(saved_xcr0 >> 32, saved_xcr0 & 0xFFFFFFFFUL);
 216         }
 217
 218         ml_set_interrupts_enabled(intrs_enabled);
 219 }
 220
 221 /* Farm an update out to all CPUs */
 222 static void
 223 xcpu_update(void)
 224 {
 225         if (register_locks() != KERN_SUCCESS)
 226                 return;
 227
 228         /* Get all CPUs to perform the update */
 229         mp_broadcast(cpu_update, NULL);
 230
 231         /* Update the cpuid info */
 232         ucode_cpuid_set_info();
 233 }
 234
 235 /*
 236  * sysctl function
 237  *
 238  */
 239 int
 240 ucode_interface(uint64_t addr)
 241 {
 242         int error;
 243         char arg[16];
 244
 245         if (PE_parse_boot_argn("-x", arg, sizeof (arg))) {
 246                 printf("ucode: no updates in safe mode\n");
 247                 return EPERM;
 248         }
 249
 250 #if !DEBUG
 251         /*
 252          * Userland may only call this once per boot. Anything else
 253          * would not make sense (all updates are cumulative), and also
 254          * leak memory, because we don't free previous updates.
 255          */
 256         if (global_update)
 257                 return EPERM;
 258 #endif
 259
 260         /* Get the whole microcode */
 261         error = copyin_update(addr);
 262
 263         if (error)
 264                 return error;
 265
 266         /* Farm out the updates */
 267         xcpu_update();
 268
 269         return 0;
 270 }