arch/x86/include/asm/msr.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _ASM_X86_MSR_H
   3 #define _ASM_X86_MSR_H
   4
   5 #include "msr-index.h"
   6
   7 #ifndef __ASSEMBLY__
   8
   9 #include <asm/asm.h>
  10 #include <asm/errno.h>
  11 #include <asm/cpumask.h>
  12 #include <uapi/asm/msr.h>
  13
  14 struct msr {
  15         union {
  16                 struct {
  17                         u32 l;
  18                         u32 h;
  19                 };
  20                 u64 q;
  21         };
  22 };
  23
  24 struct msr_info {
  25         u32 msr_no;
  26         struct msr reg;
  27         struct msr *msrs;
  28         int err;
  29 };
  30
  31 struct msr_regs_info {
  32         u32 *regs;
  33         int err;
  34 };
  35
  36 struct saved_msr {
  37         bool valid;
  38         struct msr_info info;
  39 };
  40
  41 struct saved_msrs {
  42         unsigned int num;
  43         struct saved_msr *array;
  44 };
  45
  46 /*
  47  * both i386 and x86_64 returns 64-bit value in edx:eax, but gcc's "A"
  48  * constraint has different meanings. For i386, "A" means exactly
  49  * edx:eax, while for x86_64 it doesn't mean rdx:rax or edx:eax. Instead,
  50  * it means rax *or* rdx.
  51  */
  52 #ifdef CONFIG_X86_64
  53 /* Using 64-bit values saves one instruction clearing the high half of low */
  54 #define DECLARE_ARGS(val, low, high)    unsigned long low, high
  55 #define EAX_EDX_VAL(val, low, high)     ((low) | (high) << 32)
  56 #define EAX_EDX_RET(val, low, high)     "=a" (low), "=d" (high)
  57 #else
  58 #define DECLARE_ARGS(val, low, high)    unsigned long long val
  59 #define EAX_EDX_VAL(val, low, high)     (val)
  60 #define EAX_EDX_RET(val, low, high)     "=A" (val)
  61 #endif
  62
  63 #ifdef CONFIG_TRACEPOINTS
  64 /*
  65  * Be very careful with includes. This header is prone to include loops.
  66  */
  67 #include <asm/atomic.h>
  68 #include <linux/tracepoint-defs.h>
  69
  70 extern struct tracepoint __tracepoint_read_msr;
  71 extern struct tracepoint __tracepoint_write_msr;
  72 extern struct tracepoint __tracepoint_rdpmc;
  73 #define msr_tracepoint_active(t) static_key_false(&(t).key)
  74 extern void do_trace_write_msr(unsigned int msr, u64 val, int failed);
  75 extern void do_trace_read_msr(unsigned int msr, u64 val, int failed);
  76 extern void do_trace_rdpmc(unsigned int msr, u64 val, int failed);
  77 #else
  78 #define msr_tracepoint_active(t) false
  79 static inline void do_trace_write_msr(unsigned int msr, u64 val, int failed) {}
  80 static inline void do_trace_read_msr(unsigned int msr, u64 val, int failed) {}
  81 static inline void do_trace_rdpmc(unsigned int msr, u64 val, int failed) {}
  82 #endif
  83
  84 /*
  85  * __rdmsr() and __wrmsr() are the two primitives which are the bare minimum MSR
  86  * accessors and should not have any tracing or other functionality piggybacking
  87  * on them - those are *purely* for accessing MSRs and nothing more. So don't even
  88  * think of extending them - you will be slapped with a stinking trout or a frozen
  89  * shark will reach you, wherever you are! You've been warned.
  90  */
  91 static inline unsigned long long notrace __rdmsr(unsigned int msr)
  92 {
  93         DECLARE_ARGS(val, low, high);
  94
  95         asm volatile("1: rdmsr\n"
  96                      "2:\n"
  97                      _ASM_EXTABLE_HANDLE(1b, 2b, ex_handler_rdmsr_unsafe)
  98                      : EAX_EDX_RET(val, low, high) : "c" (msr));
  99
 100         return EAX_EDX_VAL(val, low, high);
 101 }
 102
 103 static inline void notrace __wrmsr(unsigned int msr, u32 low, u32 high)
 104 {
 105         asm volatile("1: wrmsr\n"
 106                      "2:\n"
 107                      _ASM_EXTABLE_HANDLE(1b, 2b, ex_handler_wrmsr_unsafe)
 108                      : : "c" (msr), "a"(low), "d" (high) : "memory");
 109 }
 110
 111 #define native_rdmsr(msr, val1, val2)                   \
 112 do {                                                    \
 113         u64 __val = __rdmsr((msr));                     \
 114         (void)((val1) = (u32)__val);                    \
 115         (void)((val2) = (u32)(__val >> 32));            \
 116 } while (0)
 117
 118 #define native_wrmsr(msr, low, high)                    \
 119         __wrmsr(msr, low, high)
 120
 121 #define native_wrmsrl(msr, val)                         \
 122         __wrmsr((msr), (u32)((u64)(val)),               \
 123                        (u32)((u64)(val) >> 32))
 124
 125 static inline unsigned long long native_read_msr(unsigned int msr)
 126 {
 127         unsigned long long val;
 128
 129         val = __rdmsr(msr);
 130
 131         if (msr_tracepoint_active(__tracepoint_read_msr))
 132                 do_trace_read_msr(msr, val, 0);
 133
 134         return val;
 135 }
 136
 137 static inline unsigned long long native_read_msr_safe(unsigned int msr,
 138                                                       int *err)
 139 {
 140         DECLARE_ARGS(val, low, high);
 141
 142         asm volatile("2: rdmsr ; xor %[err],%[err]\n"
 143                      "1:\n\t"
 144                      ".section .fixup,\"ax\"\n\t"
 145                      "3: mov %[fault],%[err]\n\t"
 146                      "xorl %%eax, %%eax\n\t"
 147                      "xorl %%edx, %%edx\n\t"
 148                      "jmp 1b\n\t"
 149                      ".previous\n\t"
 150                      _ASM_EXTABLE(2b, 3b)
 151                      : [err] "=r" (*err), EAX_EDX_RET(val, low, high)
 152                      : "c" (msr), [fault] "i" (-EIO));
 153         if (msr_tracepoint_active(__tracepoint_read_msr))
 154                 do_trace_read_msr(msr, EAX_EDX_VAL(val, low, high), *err);
 155         return EAX_EDX_VAL(val, low, high);
 156 }
 157
 158 /* Can be uninlined because referenced by paravirt */
 159 static inline void notrace
 160 native_write_msr(unsigned int msr, u32 low, u32 high)
 161 {
 162         __wrmsr(msr, low, high);
 163
 164         if (msr_tracepoint_active(__tracepoint_write_msr))
 165                 do_trace_write_msr(msr, ((u64)high << 32 | low), 0);
 166 }
 167
 168 /* Can be uninlined because referenced by paravirt */
 169 static inline int notrace
 170 native_write_msr_safe(unsigned int msr, u32 low, u32 high)
 171 {
 172         int err;
 173
 174         asm volatile("2: wrmsr ; xor %[err],%[err]\n"
 175                      "1:\n\t"
 176                      ".section .fixup,\"ax\"\n\t"
 177                      "3:  mov %[fault],%[err] ; jmp 1b\n\t"
 178                      ".previous\n\t"
 179                      _ASM_EXTABLE(2b, 3b)
 180                      : [err] "=a" (err)
 181                      : "c" (msr), "0" (low), "d" (high),
 182                        [fault] "i" (-EIO)
 183                      : "memory");
 184         if (msr_tracepoint_active(__tracepoint_write_msr))
 185                 do_trace_write_msr(msr, ((u64)high << 32 | low), err);
 186         return err;
 187 }
 188
 189 extern int rdmsr_safe_regs(u32 regs[8]);
 190 extern int wrmsr_safe_regs(u32 regs[8]);
 191
 192 /**
 193  * rdtsc() - returns the current TSC without ordering constraints
 194  *
 195  * rdtsc() returns the result of RDTSC as a 64-bit integer.  The
 196  * only ordering constraint it supplies is the ordering implied by
 197  * "asm volatile": it will put the RDTSC in the place you expect.  The
 198  * CPU can and will speculatively execute that RDTSC, though, so the
 199  * results can be non-monotonic if compared on different CPUs.
 200  */
 201 static __always_inline unsigned long long rdtsc(void)
 202 {
 203         DECLARE_ARGS(val, low, high);
 204
 205         asm volatile("rdtsc" : EAX_EDX_RET(val, low, high));
 206
 207         return EAX_EDX_VAL(val, low, high);
 208 }
 209
 210 /**
 211  * rdtsc_ordered() - read the current TSC in program order
 212  *
 213  * rdtsc_ordered() returns the result of RDTSC as a 64-bit integer.
 214  * It is ordered like a load to a global in-memory counter.  It should
 215  * be impossible to observe non-monotonic rdtsc_unordered() behavior
 216  * across multiple CPUs as long as the TSC is synced.
 217  */
 218 static __always_inline unsigned long long rdtsc_ordered(void)
 219 {
 220         DECLARE_ARGS(val, low, high);
 221
 222         /*
 223          * The RDTSC instruction is not ordered relative to memory
 224          * access.  The Intel SDM and the AMD APM are both vague on this
 225          * point, but empirically an RDTSC instruction can be
 226          * speculatively executed before prior loads.  An RDTSC
 227          * immediately after an appropriate barrier appears to be
 228          * ordered as a normal load, that is, it provides the same
 229          * ordering guarantees as reading from a global memory location
 230          * that some other imaginary CPU is updating continuously with a
 231          * time stamp.
 232          *
 233          * Thus, use the preferred barrier on the respective CPU, aiming for
 234          * RDTSCP as the default.
 235          */
 236         asm volatile(ALTERNATIVE_2("rdtsc",
 237                                    "lfence; rdtsc", X86_FEATURE_LFENCE_RDTSC,
 238                                    "rdtscp", X86_FEATURE_RDTSCP)
 239                         : EAX_EDX_RET(val, low, high)
 240                         /* RDTSCP clobbers ECX with MSR_TSC_AUX. */
 241                         :: "ecx");
 242
 243         return EAX_EDX_VAL(val, low, high);
 244 }
 245
 246 static inline unsigned long long native_read_pmc(int counter)
 247 {
 248         DECLARE_ARGS(val, low, high);
 249
 250         asm volatile("rdpmc" : EAX_EDX_RET(val, low, high) : "c" (counter));
 251         if (msr_tracepoint_active(__tracepoint_rdpmc))
 252                 do_trace_rdpmc(counter, EAX_EDX_VAL(val, low, high), 0);
 253         return EAX_EDX_VAL(val, low, high);
 254 }
 255
 256 #ifdef CONFIG_PARAVIRT_XXL
 257 #include <asm/paravirt.h>
 258 #else
 259 #include <linux/errno.h>
 260 /*
 261  * Access to machine-specific registers (available on 586 and better only)
 262  * Note: the rd* operations modify the parameters directly (without using
 263  * pointer indirection), this allows gcc to optimize better
 264  */
 265
 266 #define rdmsr(msr, low, high)                                   \
 267 do {                                                            \
 268         u64 __val = native_read_msr((msr));                     \
 269         (void)((low) = (u32)__val);                             \
 270         (void)((high) = (u32)(__val >> 32));                    \
 271 } while (0)
 272
 273 static inline void wrmsr(unsigned int msr, u32 low, u32 high)
 274 {
 275         native_write_msr(msr, low, high);
 276 }
 277
 278 #define rdmsrl(msr, val)                        \
 279         ((val) = native_read_msr((msr)))
 280
 281 static inline void wrmsrl(unsigned int msr, u64 val)
 282 {
 283         native_write_msr(msr, (u32)(val & 0xffffffffULL), (u32)(val >> 32));
 284 }
 285
 286 /* wrmsr with exception handling */
 287 static inline int wrmsr_safe(unsigned int msr, u32 low, u32 high)
 288 {
 289         return native_write_msr_safe(msr, low, high);
 290 }
 291
 292 /* rdmsr with exception handling */
 293 #define rdmsr_safe(msr, low, high)                              \
 294 ({                                                              \
 295         int __err;                                              \
 296         u64 __val = native_read_msr_safe((msr), &__err);        \
 297         (*low) = (u32)__val;                                    \
 298         (*high) = (u32)(__val >> 32);                           \
 299         __err;                                                  \
 300 })
 301
 302 static inline int rdmsrl_safe(unsigned int msr, unsigned long long *p)
 303 {
 304         int err;
 305
 306         *p = native_read_msr_safe(msr, &err);
 307         return err;
 308 }
 309
 310 #define rdpmc(counter, low, high)                       \
 311 do {                                                    \
 312         u64 _l = native_read_pmc((counter));            \
 313         (low)  = (u32)_l;                               \
 314         (high) = (u32)(_l >> 32);                       \
 315 } while (0)
 316
 317 #define rdpmcl(counter, val) ((val) = native_read_pmc(counter))
 318
 319 #endif  /* !CONFIG_PARAVIRT_XXL */
 320
 321 /*
 322  * 64-bit version of wrmsr_safe():
 323  */
 324 static inline int wrmsrl_safe(u32 msr, u64 val)
 325 {
 326         return wrmsr_safe(msr, (u32)val,  (u32)(val >> 32));
 327 }
 328
 329 #define write_tsc(low, high) wrmsr(MSR_IA32_TSC, (low), (high))
 330
 331 #define write_rdtscp_aux(val) wrmsr(MSR_TSC_AUX, (val), 0)
 332
 333 struct msr *msrs_alloc(void);
 334 void msrs_free(struct msr *msrs);
 335 int msr_set_bit(u32 msr, u8 bit);
 336 int msr_clear_bit(u32 msr, u8 bit);
 337
 338 #ifdef CONFIG_SMP
 339 int rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h);
 340 int wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h);
 341 int rdmsrl_on_cpu(unsigned int cpu, u32 msr_no, u64 *q);
 342 int wrmsrl_on_cpu(unsigned int cpu, u32 msr_no, u64 q);
 343 void rdmsr_on_cpus(const struct cpumask *mask, u32 msr_no, struct msr *msrs);
 344 void wrmsr_on_cpus(const struct cpumask *mask, u32 msr_no, struct msr *msrs);
 345 int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h);
 346 int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h);
 347 int rdmsrl_safe_on_cpu(unsigned int cpu, u32 msr_no, u64 *q);
 348 int wrmsrl_safe_on_cpu(unsigned int cpu, u32 msr_no, u64 q);
 349 int rdmsr_safe_regs_on_cpu(unsigned int cpu, u32 regs[8]);
 350 int wrmsr_safe_regs_on_cpu(unsigned int cpu, u32 regs[8]);
 351 #else  /*  CONFIG_SMP  */
 352 static inline int rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
 353 {
 354         rdmsr(msr_no, *l, *h);
 355         return 0;
 356 }
 357 static inline int wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
 358 {
 359         wrmsr(msr_no, l, h);
 360         return 0;
 361 }
 362 static inline int rdmsrl_on_cpu(unsigned int cpu, u32 msr_no, u64 *q)
 363 {
 364         rdmsrl(msr_no, *q);
 365         return 0;
 366 }
 367 static inline int wrmsrl_on_cpu(unsigned int cpu, u32 msr_no, u64 q)
 368 {
 369         wrmsrl(msr_no, q);
 370         return 0;
 371 }
 372 static inline void rdmsr_on_cpus(const struct cpumask *m, u32 msr_no,
 373                                 struct msr *msrs)
 374 {
 375         rdmsr_on_cpu(0, msr_no, &(msrs[0].l), &(msrs[0].h));
 376 }
 377 static inline void wrmsr_on_cpus(const struct cpumask *m, u32 msr_no,
 378                                 struct msr *msrs)
 379 {
 380         wrmsr_on_cpu(0, msr_no, msrs[0].l, msrs[0].h);
 381 }
 382 static inline int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no,
 383                                     u32 *l, u32 *h)
 384 {
 385         return rdmsr_safe(msr_no, l, h);
 386 }
 387 static inline int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
 388 {
 389         return wrmsr_safe(msr_no, l, h);
 390 }
 391 static inline int rdmsrl_safe_on_cpu(unsigned int cpu, u32 msr_no, u64 *q)
 392 {
 393         return rdmsrl_safe(msr_no, q);
 394 }
 395 static inline int wrmsrl_safe_on_cpu(unsigned int cpu, u32 msr_no, u64 q)
 396 {
 397         return wrmsrl_safe(msr_no, q);
 398 }
 399 static inline int rdmsr_safe_regs_on_cpu(unsigned int cpu, u32 regs[8])
 400 {
 401         return rdmsr_safe_regs(regs);
 402 }
 403 static inline int wrmsr_safe_regs_on_cpu(unsigned int cpu, u32 regs[8])
 404 {
 405         return wrmsr_safe_regs(regs);
 406 }
 407 #endif  /* CONFIG_SMP */
 408 #endif /* __ASSEMBLY__ */
 409 #endif /* _ASM_X86_MSR_H */