osfmk/i386/ucode.c

   1 /*
   2  * Copyright (c) 2017-2019 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/cpu_data.h> // mp_*_preemption
  41 #include <i386/mp.h> // mp_cpus_call
  42 #include <i386/commpage/commpage.h>
  43 #include <i386/fpu.h>
  44 #include <machine/cpu_number.h> // cpu_number
  45 #include <pexpert/pexpert.h>  // boot-args
  46
  47 #define IA32_BIOS_UPDT_TRIG (0x79) /* microcode update trigger MSR */
  48
  49 struct intel_ucupdate *global_update = NULL;
  50
  51 /* Exceute the actual update! */
  52 static void
  53 update_microcode(void)
  54 {
  55         /* SDM Example 9-8 code shows that we load the
  56          * address of the UpdateData within the microcode blob,
  57          * not the address of the header.
  58          */
  59         wrmsr64(IA32_BIOS_UPDT_TRIG, (uint64_t)(uintptr_t)&global_update->data);
  60 }
  61
  62 /* locks */
  63 static lck_grp_attr_t *ucode_slock_grp_attr = NULL;
  64 static lck_grp_t *ucode_slock_grp = NULL;
  65 static lck_attr_t *ucode_slock_attr = NULL;
  66 static lck_spin_t *ucode_slock = NULL;
  67
  68 static kern_return_t
  69 register_locks(void)
  70 {
  71         /* already allocated? */
  72         if (ucode_slock_grp_attr && ucode_slock_grp && ucode_slock_attr && ucode_slock) {
  73                 return KERN_SUCCESS;
  74         }
  75
  76         /* allocate lock group attribute and group */
  77         if (!(ucode_slock_grp_attr = lck_grp_attr_alloc_init())) {
  78                 goto nomem_out;
  79         }
  80
  81         if (!(ucode_slock_grp = lck_grp_alloc_init("uccode_lock", ucode_slock_grp_attr))) {
  82                 goto nomem_out;
  83         }
  84
  85         /* Allocate lock attribute */
  86         if (!(ucode_slock_attr = lck_attr_alloc_init())) {
  87                 goto nomem_out;
  88         }
  89
  90         /* Allocate the spin lock */
  91         /* We keep one global spin-lock. We could have one per update
  92          * request... but srsly, why would you update microcode like that?
  93          */
  94         if (!(ucode_slock = lck_spin_alloc_init(ucode_slock_grp, ucode_slock_attr))) {
  95                 goto nomem_out;
  96         }
  97
  98         return KERN_SUCCESS;
  99
 100 nomem_out:
 101         /* clean up */
 102         if (ucode_slock) {
 103                 lck_spin_free(ucode_slock, ucode_slock_grp);
 104         }
 105         if (ucode_slock_attr) {
 106                 lck_attr_free(ucode_slock_attr);
 107         }
 108         if (ucode_slock_grp) {
 109                 lck_grp_free(ucode_slock_grp);
 110         }
 111         if (ucode_slock_grp_attr) {
 112                 lck_grp_attr_free(ucode_slock_grp_attr);
 113         }
 114
 115         return KERN_NO_SPACE;
 116 }
 117
 118 /* Copy in an update */
 119 static int
 120 copyin_update(uint64_t inaddr)
 121 {
 122         struct intel_ucupdate update_header;
 123         struct intel_ucupdate *update;
 124         vm_size_t size;
 125         kern_return_t ret;
 126         int error;
 127
 128         /* Copy in enough header to peek at the size */
 129         error = copyin((user_addr_t)inaddr, (void *)&update_header, sizeof(update_header));
 130         if (error) {
 131                 return error;
 132         }
 133
 134         /* Get the actual, alleged size */
 135         size = update_header.total_size;
 136
 137         /* huge bogus piece of data that somehow made it through? */
 138         if (size >= 1024 * 1024) {
 139                 return ENOMEM;
 140         }
 141
 142         /* Old microcodes? */
 143         if (size == 0) {
 144                 size = 2048; /* default update size; see SDM */
 145         }
 146         /*
 147          * create the buffer for the update
 148          * It need only be aligned to 16-bytes, according to the SDM.
 149          * This also wires it down
 150          */
 151         ret = kmem_alloc_kobject(kernel_map, (vm_offset_t *)&update, size, VM_KERN_MEMORY_OSFMK);
 152         if (ret != KERN_SUCCESS) {
 153                 return ENOMEM;
 154         }
 155
 156         /* Copy it in */
 157         error = copyin((user_addr_t)inaddr, (void*)update, size);
 158         if (error) {
 159                 kmem_free(kernel_map, (vm_offset_t)update, size);
 160                 return error;
 161         }
 162
 163         global_update = update;
 164         return 0;
 165 }
 166
 167 static void
 168 cpu_apply_microcode(void)
 169 {
 170         /* grab the lock */
 171         lck_spin_lock(ucode_slock);
 172
 173         /* execute the update */
 174         update_microcode();
 175
 176         /* release the lock */
 177         lck_spin_unlock(ucode_slock);
 178 }
 179
 180 static void
 181 cpu_update(__unused void *arg)
 182 {
 183         cpu_apply_microcode();
 184
 185         cpuid_do_was();
 186 }
 187
 188 /*
 189  * This is called once by every CPU on a wake from sleep/hibernate
 190  * and is meant to re-apply a microcode update that got lost
 191  * by sleeping.
 192  */
 193 void
 194 ucode_update_wake_and_apply_cpu_was()
 195 {
 196         if (global_update) {
 197                 kprintf("ucode: Re-applying update after wake (CPU #%d)\n", cpu_number());
 198                 cpu_update(NULL);
 199         } else {
 200                 cpuid_do_was();
 201 #if DEBUG
 202                 kprintf("ucode: No update to apply (CPU #%d)\n", cpu_number());
 203 #endif
 204         }
 205 }
 206
 207 static void
 208 ucode_cpuid_set_info(void)
 209 {
 210         uint64_t saved_xcr0, dest_xcr0;
 211         int need_xcr0_restore = 0;
 212         boolean_t intrs_enabled = ml_set_interrupts_enabled(FALSE);
 213
 214         /*
 215          * Before we cache the CPUID information, we must configure XCR0 with the maximal set of
 216          * features to ensure the save area returned in the xsave leaf is correctly-sized.
 217          *
 218          * Since we are guaranteed that init_fpu() has already happened, we can use state
 219          * variables set there that were already predicated on the presence of explicit
 220          * boot-args enables/disables.
 221          */
 222
 223         if (fpu_capability == AVX512 || fpu_capability == AVX) {
 224                 saved_xcr0 = xgetbv(XCR0);
 225                 dest_xcr0 = (fpu_capability == AVX512) ? AVX512_XMASK : AVX_XMASK;
 226                 assert((get_cr4() & CR4_OSXSAVE) != 0);
 227                 if (saved_xcr0 != dest_xcr0) {
 228                         need_xcr0_restore = 1;
 229                         xsetbv(dest_xcr0 >> 32, dest_xcr0 & 0xFFFFFFFFUL);
 230                 }
 231         }
 232
 233         cpuid_set_info();
 234
 235         if (need_xcr0_restore) {
 236                 xsetbv(saved_xcr0 >> 32, saved_xcr0 & 0xFFFFFFFFUL);
 237         }
 238
 239         ml_set_interrupts_enabled(intrs_enabled);
 240 }
 241
 242 /* Farm an update out to all CPUs */
 243 static void
 244 xcpu_update(void)
 245 {
 246         cpumask_t dest_cpumask;
 247
 248         if (register_locks() != KERN_SUCCESS) {
 249                 return;
 250         }
 251
 252         mp_disable_preemption();
 253         dest_cpumask = CPUMASK_OTHERS;
 254         cpu_apply_microcode();
 255         /* Update the cpuid info */
 256         ucode_cpuid_set_info();
 257         mp_enable_preemption();
 258
 259         /* Get all other CPUs to perform the update */
 260         /*
 261          * Calling mp_cpus_call with the ASYNC flag ensures that the
 262          * IPI dispatch occurs in parallel, but that we will not
 263          * proceed until all targeted CPUs complete the microcode
 264          * update.
 265          */
 266         mp_cpus_call(dest_cpumask, ASYNC, cpu_update, NULL);
 267
 268         /* Update the commpage only after we update all CPUs' microcode */
 269         commpage_post_ucode_update();
 270 }
 271
 272 /*
 273  * sysctl function
 274  *
 275  */
 276 int
 277 ucode_interface(uint64_t addr)
 278 {
 279         int error;
 280         char arg[16];
 281
 282         if (PE_parse_boot_argn("-x", arg, sizeof(arg))) {
 283                 printf("ucode: no updates in safe mode\n");
 284                 return EPERM;
 285         }
 286
 287 #if !DEBUG
 288         /*
 289          * Userland may only call this once per boot. Anything else
 290          * would not make sense (all updates are cumulative), and also
 291          * leak memory, because we don't free previous updates.
 292          */
 293         if (global_update) {
 294                 return EPERM;
 295         }
 296 #endif
 297
 298         /* Get the whole microcode */
 299         error = copyin_update(addr);
 300
 301         if (error) {
 302                 return error;
 303         }
 304
 305         /* Farm out the updates */
 306         xcpu_update();
 307
 308         return 0;
 309 }