2 * xsave/xrstor support.
4 * Author: Suresh Siddha <suresh.b.siddha@intel.com>
6 #include <linux/compat.h>
8 #include <linux/mman.h>
9 #include <linux/pkeys.h>
11 #include <asm/fpu/api.h>
12 #include <asm/fpu/internal.h>
13 #include <asm/fpu/signal.h>
14 #include <asm/fpu/regset.h>
15 #include <asm/fpu/xstate.h>
17 #include <asm/tlbflush.h>
20 * Although we spell it out in here, the Processor Trace
21 * xfeature is completely unused. We use other mechanisms
22 * to save/restore PT state in Linux.
24 static const char *xfeature_names
[] =
26 "x87 floating point registers" ,
29 "MPX bounds registers" ,
34 "Processor Trace (unused)" ,
35 "Protection Keys User registers",
36 "unknown xstate feature" ,
40 * Mask of xstate features supported by the CPU and the kernel:
42 u64 xfeatures_mask __read_mostly
;
44 static unsigned int xstate_offsets
[XFEATURE_MAX
] = { [ 0 ... XFEATURE_MAX
- 1] = -1};
45 static unsigned int xstate_sizes
[XFEATURE_MAX
] = { [ 0 ... XFEATURE_MAX
- 1] = -1};
46 static unsigned int xstate_comp_offsets
[sizeof(xfeatures_mask
)*8];
49 * The XSAVE area of kernel can be in standard or compacted format;
50 * it is always in standard format for user mode. This is the user
51 * mode standard format size used for signal and ptrace frames.
53 unsigned int fpu_user_xstate_size
;
56 * Clear all of the X86_FEATURE_* bits that are unavailable
57 * when the CPU has no XSAVE support.
59 void fpu__xstate_clear_all_cpu_caps(void)
61 setup_clear_cpu_cap(X86_FEATURE_XSAVE
);
62 setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT
);
63 setup_clear_cpu_cap(X86_FEATURE_XSAVEC
);
64 setup_clear_cpu_cap(X86_FEATURE_XSAVES
);
65 setup_clear_cpu_cap(X86_FEATURE_AVX
);
66 setup_clear_cpu_cap(X86_FEATURE_AVX2
);
67 setup_clear_cpu_cap(X86_FEATURE_AVX512F
);
68 setup_clear_cpu_cap(X86_FEATURE_AVX512IFMA
);
69 setup_clear_cpu_cap(X86_FEATURE_AVX512PF
);
70 setup_clear_cpu_cap(X86_FEATURE_AVX512ER
);
71 setup_clear_cpu_cap(X86_FEATURE_AVX512CD
);
72 setup_clear_cpu_cap(X86_FEATURE_AVX512DQ
);
73 setup_clear_cpu_cap(X86_FEATURE_AVX512BW
);
74 setup_clear_cpu_cap(X86_FEATURE_AVX512VL
);
75 setup_clear_cpu_cap(X86_FEATURE_MPX
);
76 setup_clear_cpu_cap(X86_FEATURE_XGETBV1
);
77 setup_clear_cpu_cap(X86_FEATURE_AVX512VBMI
);
78 setup_clear_cpu_cap(X86_FEATURE_PKU
);
79 setup_clear_cpu_cap(X86_FEATURE_AVX512_4VNNIW
);
80 setup_clear_cpu_cap(X86_FEATURE_AVX512_4FMAPS
);
81 setup_clear_cpu_cap(X86_FEATURE_AVX512_VPOPCNTDQ
);
85 * Return whether the system supports a given xfeature.
87 * Also return the name of the (most advanced) feature that the caller requested:
89 int cpu_has_xfeatures(u64 xfeatures_needed
, const char **feature_name
)
91 u64 xfeatures_missing
= xfeatures_needed
& ~xfeatures_mask
;
93 if (unlikely(feature_name
)) {
94 long xfeature_idx
, max_idx
;
97 * So we use FLS here to be able to print the most advanced
98 * feature that was requested but is missing. So if a driver
99 * asks about "XFEATURE_MASK_SSE | XFEATURE_MASK_YMM" we'll print the
100 * missing AVX feature - this is the most informative message
103 if (xfeatures_missing
)
104 xfeatures_print
= xfeatures_missing
;
106 xfeatures_print
= xfeatures_needed
;
108 xfeature_idx
= fls64(xfeatures_print
)-1;
109 max_idx
= ARRAY_SIZE(xfeature_names
)-1;
110 xfeature_idx
= min(xfeature_idx
, max_idx
);
112 *feature_name
= xfeature_names
[xfeature_idx
];
115 if (xfeatures_missing
)
120 EXPORT_SYMBOL_GPL(cpu_has_xfeatures
);
122 static int xfeature_is_supervisor(int xfeature_nr
)
125 * We currently do not support supervisor states, but if
126 * we did, we could find out like this.
128 * SDM says: If state component 'i' is a user state component,
129 * ECX[0] return 0; if state component i is a supervisor
130 * state component, ECX[0] returns 1.
132 u32 eax
, ebx
, ecx
, edx
;
134 cpuid_count(XSTATE_CPUID
, xfeature_nr
, &eax
, &ebx
, &ecx
, &edx
);
138 static int xfeature_is_user(int xfeature_nr
)
140 return !xfeature_is_supervisor(xfeature_nr
);
144 * When executing XSAVEOPT (or other optimized XSAVE instructions), if
145 * a processor implementation detects that an FPU state component is still
146 * (or is again) in its initialized state, it may clear the corresponding
147 * bit in the header.xfeatures field, and can skip the writeout of registers
148 * to the corresponding memory layout.
150 * This means that when the bit is zero, the state component might still contain
151 * some previous - non-initialized register state.
153 * Before writing xstate information to user-space we sanitize those components,
154 * to always ensure that the memory layout of a feature will be in the init state
155 * if the corresponding header bit is zero. This is to ensure that user-space doesn't
156 * see some stale state in the memory layout during signal handling, debugging etc.
158 void fpstate_sanitize_xstate(struct fpu
*fpu
)
160 struct fxregs_state
*fx
= &fpu
->state
.fxsave
;
167 xfeatures
= fpu
->state
.xsave
.header
.xfeatures
;
170 * None of the feature bits are in init state. So nothing else
171 * to do for us, as the memory layout is up to date.
173 if ((xfeatures
& xfeatures_mask
) == xfeatures_mask
)
177 * FP is in init state
179 if (!(xfeatures
& XFEATURE_MASK_FP
)) {
186 memset(&fx
->st_space
[0], 0, 128);
190 * SSE is in init state
192 if (!(xfeatures
& XFEATURE_MASK_SSE
))
193 memset(&fx
->xmm_space
[0], 0, 256);
196 * First two features are FPU and SSE, which above we handled
197 * in a special way already:
200 xfeatures
= (xfeatures_mask
& ~xfeatures
) >> 2;
203 * Update all the remaining memory layouts according to their
204 * standard xstate layout, if their header bit is in the init
208 if (xfeatures
& 0x1) {
209 int offset
= xstate_comp_offsets
[feature_bit
];
210 int size
= xstate_sizes
[feature_bit
];
212 memcpy((void *)fx
+ offset
,
213 (void *)&init_fpstate
.xsave
+ offset
,
223 * Enable the extended processor state save/restore feature.
224 * Called once per CPU onlining.
226 void fpu__init_cpu_xstate(void)
228 if (!boot_cpu_has(X86_FEATURE_XSAVE
) || !xfeatures_mask
)
231 * Make it clear that XSAVES supervisor states are not yet
232 * implemented should anyone expect it to work by changing
233 * bits in XFEATURE_MASK_* macros and XCR0.
235 WARN_ONCE((xfeatures_mask
& XFEATURE_MASK_SUPERVISOR
),
236 "x86/fpu: XSAVES supervisor states are not yet implemented.\n");
238 xfeatures_mask
&= ~XFEATURE_MASK_SUPERVISOR
;
240 cr4_set_bits(X86_CR4_OSXSAVE
);
241 xsetbv(XCR_XFEATURE_ENABLED_MASK
, xfeatures_mask
);
245 * Note that in the future we will likely need a pair of
246 * functions here: one for user xstates and the other for
247 * system xstates. For now, they are the same.
249 static int xfeature_enabled(enum xfeature xfeature
)
251 return !!(xfeatures_mask
& (1UL << xfeature
));
255 * Record the offsets and sizes of various xstates contained
256 * in the XSAVE state memory layout.
258 static void __init
setup_xstate_features(void)
260 u32 eax
, ebx
, ecx
, edx
, i
;
261 /* start at the beginnning of the "extended state" */
262 unsigned int last_good_offset
= offsetof(struct xregs_state
,
263 extended_state_area
);
265 * The FP xstates and SSE xstates are legacy states. They are always
266 * in the fixed offsets in the xsave area in either compacted form
269 xstate_offsets
[0] = 0;
270 xstate_sizes
[0] = offsetof(struct fxregs_state
, xmm_space
);
271 xstate_offsets
[1] = xstate_sizes
[0];
272 xstate_sizes
[1] = FIELD_SIZEOF(struct fxregs_state
, xmm_space
);
274 for (i
= FIRST_EXTENDED_XFEATURE
; i
< XFEATURE_MAX
; i
++) {
275 if (!xfeature_enabled(i
))
278 cpuid_count(XSTATE_CPUID
, i
, &eax
, &ebx
, &ecx
, &edx
);
281 * If an xfeature is supervisor state, the offset
282 * in EBX is invalid. We leave it to -1.
284 if (xfeature_is_user(i
))
285 xstate_offsets
[i
] = ebx
;
287 xstate_sizes
[i
] = eax
;
289 * In our xstate size checks, we assume that the
290 * highest-numbered xstate feature has the
291 * highest offset in the buffer. Ensure it does.
293 WARN_ONCE(last_good_offset
> xstate_offsets
[i
],
294 "x86/fpu: misordered xstate at %d\n", last_good_offset
);
295 last_good_offset
= xstate_offsets
[i
];
299 static void __init
print_xstate_feature(u64 xstate_mask
)
301 const char *feature_name
;
303 if (cpu_has_xfeatures(xstate_mask
, &feature_name
))
304 pr_info("x86/fpu: Supporting XSAVE feature 0x%03Lx: '%s'\n", xstate_mask
, feature_name
);
308 * Print out all the supported xstate features:
310 static void __init
print_xstate_features(void)
312 print_xstate_feature(XFEATURE_MASK_FP
);
313 print_xstate_feature(XFEATURE_MASK_SSE
);
314 print_xstate_feature(XFEATURE_MASK_YMM
);
315 print_xstate_feature(XFEATURE_MASK_BNDREGS
);
316 print_xstate_feature(XFEATURE_MASK_BNDCSR
);
317 print_xstate_feature(XFEATURE_MASK_OPMASK
);
318 print_xstate_feature(XFEATURE_MASK_ZMM_Hi256
);
319 print_xstate_feature(XFEATURE_MASK_Hi16_ZMM
);
320 print_xstate_feature(XFEATURE_MASK_PKRU
);
324 * This check is important because it is easy to get XSTATE_*
325 * confused with XSTATE_BIT_*.
327 #define CHECK_XFEATURE(nr) do { \
328 WARN_ON(nr < FIRST_EXTENDED_XFEATURE); \
329 WARN_ON(nr >= XFEATURE_MAX); \
333 * We could cache this like xstate_size[], but we only use
334 * it here, so it would be a waste of space.
336 static int xfeature_is_aligned(int xfeature_nr
)
338 u32 eax
, ebx
, ecx
, edx
;
340 CHECK_XFEATURE(xfeature_nr
);
341 cpuid_count(XSTATE_CPUID
, xfeature_nr
, &eax
, &ebx
, &ecx
, &edx
);
343 * The value returned by ECX[1] indicates the alignment
344 * of state component 'i' when the compacted format
345 * of the extended region of an XSAVE area is used:
351 * This function sets up offsets and sizes of all extended states in
352 * xsave area. This supports both standard format and compacted format
353 * of the xsave aread.
355 static void __init
setup_xstate_comp(void)
357 unsigned int xstate_comp_sizes
[sizeof(xfeatures_mask
)*8];
361 * The FP xstates and SSE xstates are legacy states. They are always
362 * in the fixed offsets in the xsave area in either compacted form
365 xstate_comp_offsets
[0] = 0;
366 xstate_comp_offsets
[1] = offsetof(struct fxregs_state
, xmm_space
);
368 if (!boot_cpu_has(X86_FEATURE_XSAVES
)) {
369 for (i
= FIRST_EXTENDED_XFEATURE
; i
< XFEATURE_MAX
; i
++) {
370 if (xfeature_enabled(i
)) {
371 xstate_comp_offsets
[i
] = xstate_offsets
[i
];
372 xstate_comp_sizes
[i
] = xstate_sizes
[i
];
378 xstate_comp_offsets
[FIRST_EXTENDED_XFEATURE
] =
379 FXSAVE_SIZE
+ XSAVE_HDR_SIZE
;
381 for (i
= FIRST_EXTENDED_XFEATURE
; i
< XFEATURE_MAX
; i
++) {
382 if (xfeature_enabled(i
))
383 xstate_comp_sizes
[i
] = xstate_sizes
[i
];
385 xstate_comp_sizes
[i
] = 0;
387 if (i
> FIRST_EXTENDED_XFEATURE
) {
388 xstate_comp_offsets
[i
] = xstate_comp_offsets
[i
-1]
389 + xstate_comp_sizes
[i
-1];
391 if (xfeature_is_aligned(i
))
392 xstate_comp_offsets
[i
] =
393 ALIGN(xstate_comp_offsets
[i
], 64);
399 * Print out xstate component offsets and sizes
401 static void __init
print_xstate_offset_size(void)
405 for (i
= FIRST_EXTENDED_XFEATURE
; i
< XFEATURE_MAX
; i
++) {
406 if (!xfeature_enabled(i
))
408 pr_info("x86/fpu: xstate_offset[%d]: %4d, xstate_sizes[%d]: %4d\n",
409 i
, xstate_comp_offsets
[i
], i
, xstate_sizes
[i
]);
414 * setup the xstate image representing the init state
416 static void __init
setup_init_fpu_buf(void)
418 static int on_boot_cpu __initdata
= 1;
420 WARN_ON_FPU(!on_boot_cpu
);
423 if (!boot_cpu_has(X86_FEATURE_XSAVE
))
426 setup_xstate_features();
427 print_xstate_features();
429 if (boot_cpu_has(X86_FEATURE_XSAVES
))
430 init_fpstate
.xsave
.header
.xcomp_bv
= (u64
)1 << 63 | xfeatures_mask
;
433 * Init all the features state with header.xfeatures being 0x0
435 copy_kernel_to_xregs_booting(&init_fpstate
.xsave
);
438 * Dump the init state again. This is to identify the init state
439 * of any feature which is not represented by all zero's.
441 copy_xregs_to_kernel_booting(&init_fpstate
.xsave
);
444 static int xfeature_uncompacted_offset(int xfeature_nr
)
446 u32 eax
, ebx
, ecx
, edx
;
449 * Only XSAVES supports supervisor states and it uses compacted
450 * format. Checking a supervisor state's uncompacted offset is
453 if (XFEATURE_MASK_SUPERVISOR
& (1 << xfeature_nr
)) {
454 WARN_ONCE(1, "No fixed offset for xstate %d\n", xfeature_nr
);
458 CHECK_XFEATURE(xfeature_nr
);
459 cpuid_count(XSTATE_CPUID
, xfeature_nr
, &eax
, &ebx
, &ecx
, &edx
);
463 static int xfeature_size(int xfeature_nr
)
465 u32 eax
, ebx
, ecx
, edx
;
467 CHECK_XFEATURE(xfeature_nr
);
468 cpuid_count(XSTATE_CPUID
, xfeature_nr
, &eax
, &ebx
, &ecx
, &edx
);
473 * 'XSAVES' implies two different things:
474 * 1. saving of supervisor/system state
475 * 2. using the compacted format
477 * Use this function when dealing with the compacted format so
478 * that it is obvious which aspect of 'XSAVES' is being handled
479 * by the calling code.
481 int using_compacted_format(void)
483 return boot_cpu_has(X86_FEATURE_XSAVES
);
486 static void __xstate_dump_leaves(void)
489 u32 eax
, ebx
, ecx
, edx
;
490 static int should_dump
= 1;
496 * Dump out a few leaves past the ones that we support
497 * just in case there are some goodies up there
499 for (i
= 0; i
< XFEATURE_MAX
+ 10; i
++) {
500 cpuid_count(XSTATE_CPUID
, i
, &eax
, &ebx
, &ecx
, &edx
);
501 pr_warn("CPUID[%02x, %02x]: eax=%08x ebx=%08x ecx=%08x edx=%08x\n",
502 XSTATE_CPUID
, i
, eax
, ebx
, ecx
, edx
);
506 #define XSTATE_WARN_ON(x) do { \
507 if (WARN_ONCE(x, "XSAVE consistency problem, dumping leaves")) { \
508 __xstate_dump_leaves(); \
512 #define XCHECK_SZ(sz, nr, nr_macro, __struct) do { \
513 if ((nr == nr_macro) && \
514 WARN_ONCE(sz != sizeof(__struct), \
515 "%s: struct is %zu bytes, cpu state %d bytes\n", \
516 __stringify(nr_macro), sizeof(__struct), sz)) { \
517 __xstate_dump_leaves(); \
522 * We have a C struct for each 'xstate'. We need to ensure
523 * that our software representation matches what the CPU
524 * tells us about the state's size.
526 static void check_xstate_against_struct(int nr
)
529 * Ask the CPU for the size of the state.
531 int sz
= xfeature_size(nr
);
533 * Match each CPU state with the corresponding software
536 XCHECK_SZ(sz
, nr
, XFEATURE_YMM
, struct ymmh_struct
);
537 XCHECK_SZ(sz
, nr
, XFEATURE_BNDREGS
, struct mpx_bndreg_state
);
538 XCHECK_SZ(sz
, nr
, XFEATURE_BNDCSR
, struct mpx_bndcsr_state
);
539 XCHECK_SZ(sz
, nr
, XFEATURE_OPMASK
, struct avx_512_opmask_state
);
540 XCHECK_SZ(sz
, nr
, XFEATURE_ZMM_Hi256
, struct avx_512_zmm_uppers_state
);
541 XCHECK_SZ(sz
, nr
, XFEATURE_Hi16_ZMM
, struct avx_512_hi16_state
);
542 XCHECK_SZ(sz
, nr
, XFEATURE_PKRU
, struct pkru_state
);
545 * Make *SURE* to add any feature numbers in below if
546 * there are "holes" in the xsave state component
549 if ((nr
< XFEATURE_YMM
) ||
550 (nr
>= XFEATURE_MAX
) ||
551 (nr
== XFEATURE_PT_UNIMPLEMENTED_SO_FAR
)) {
552 WARN_ONCE(1, "no structure for xstate: %d\n", nr
);
558 * This essentially double-checks what the cpu told us about
559 * how large the XSAVE buffer needs to be. We are recalculating
562 static void do_extra_xstate_size_checks(void)
564 int paranoid_xstate_size
= FXSAVE_SIZE
+ XSAVE_HDR_SIZE
;
567 for (i
= FIRST_EXTENDED_XFEATURE
; i
< XFEATURE_MAX
; i
++) {
568 if (!xfeature_enabled(i
))
571 check_xstate_against_struct(i
);
573 * Supervisor state components can be managed only by
574 * XSAVES, which is compacted-format only.
576 if (!using_compacted_format())
577 XSTATE_WARN_ON(xfeature_is_supervisor(i
));
579 /* Align from the end of the previous feature */
580 if (xfeature_is_aligned(i
))
581 paranoid_xstate_size
= ALIGN(paranoid_xstate_size
, 64);
583 * The offset of a given state in the non-compacted
584 * format is given to us in a CPUID leaf. We check
585 * them for being ordered (increasing offsets) in
586 * setup_xstate_features().
588 if (!using_compacted_format())
589 paranoid_xstate_size
= xfeature_uncompacted_offset(i
);
591 * The compacted-format offset always depends on where
592 * the previous state ended.
594 paranoid_xstate_size
+= xfeature_size(i
);
596 XSTATE_WARN_ON(paranoid_xstate_size
!= fpu_kernel_xstate_size
);
601 * Get total size of enabled xstates in XCR0/xfeatures_mask.
603 * Note the SDM's wording here. "sub-function 0" only enumerates
604 * the size of the *user* states. If we use it to size a buffer
605 * that we use 'XSAVES' on, we could potentially overflow the
606 * buffer because 'XSAVES' saves system states too.
608 * Note that we do not currently set any bits on IA32_XSS so
609 * 'XCR0 | IA32_XSS == XCR0' for now.
611 static unsigned int __init
get_xsaves_size(void)
613 unsigned int eax
, ebx
, ecx
, edx
;
615 * - CPUID function 0DH, sub-function 1:
616 * EBX enumerates the size (in bytes) required by
617 * the XSAVES instruction for an XSAVE area
618 * containing all the state components
619 * corresponding to bits currently set in
622 cpuid_count(XSTATE_CPUID
, 1, &eax
, &ebx
, &ecx
, &edx
);
626 static unsigned int __init
get_xsave_size(void)
628 unsigned int eax
, ebx
, ecx
, edx
;
630 * - CPUID function 0DH, sub-function 0:
631 * EBX enumerates the size (in bytes) required by
632 * the XSAVE instruction for an XSAVE area
633 * containing all the *user* state components
634 * corresponding to bits currently set in XCR0.
636 cpuid_count(XSTATE_CPUID
, 0, &eax
, &ebx
, &ecx
, &edx
);
641 * Will the runtime-enumerated 'xstate_size' fit in the init
642 * task's statically-allocated buffer?
644 static bool is_supported_xstate_size(unsigned int test_xstate_size
)
646 if (test_xstate_size
<= sizeof(union fpregs_state
))
649 pr_warn("x86/fpu: xstate buffer too small (%zu < %d), disabling xsave\n",
650 sizeof(union fpregs_state
), test_xstate_size
);
654 static int init_xstate_size(void)
656 /* Recompute the context size for enabled features: */
657 unsigned int possible_xstate_size
;
658 unsigned int xsave_size
;
660 xsave_size
= get_xsave_size();
662 if (boot_cpu_has(X86_FEATURE_XSAVES
))
663 possible_xstate_size
= get_xsaves_size();
665 possible_xstate_size
= xsave_size
;
667 /* Ensure we have the space to store all enabled: */
668 if (!is_supported_xstate_size(possible_xstate_size
))
672 * The size is OK, we are definitely going to use xsave,
673 * make it known to the world that we need more space.
675 fpu_kernel_xstate_size
= possible_xstate_size
;
676 do_extra_xstate_size_checks();
679 * User space is always in standard format.
681 fpu_user_xstate_size
= xsave_size
;
686 * We enabled the XSAVE hardware, but something went wrong and
687 * we can not use it. Disable it.
689 static void fpu__init_disable_system_xstate(void)
692 cr4_clear_bits(X86_CR4_OSXSAVE
);
693 fpu__xstate_clear_all_cpu_caps();
697 * Enable and initialize the xsave feature.
698 * Called once per system bootup.
700 void __init
fpu__init_system_xstate(void)
702 unsigned int eax
, ebx
, ecx
, edx
;
703 static int on_boot_cpu __initdata
= 1;
706 WARN_ON_FPU(!on_boot_cpu
);
709 if (!boot_cpu_has(X86_FEATURE_FPU
)) {
710 pr_info("x86/fpu: No FPU detected\n");
714 if (!boot_cpu_has(X86_FEATURE_XSAVE
)) {
715 pr_info("x86/fpu: x87 FPU will use %s\n",
716 boot_cpu_has(X86_FEATURE_FXSR
) ? "FXSAVE" : "FSAVE");
720 if (boot_cpu_data
.cpuid_level
< XSTATE_CPUID
) {
725 cpuid_count(XSTATE_CPUID
, 0, &eax
, &ebx
, &ecx
, &edx
);
726 xfeatures_mask
= eax
+ ((u64
)edx
<< 32);
728 if ((xfeatures_mask
& XFEATURE_MASK_FPSSE
) != XFEATURE_MASK_FPSSE
) {
730 * This indicates that something really unexpected happened
731 * with the enumeration. Disable XSAVE and try to continue
732 * booting without it. This is too early to BUG().
734 pr_err("x86/fpu: FP/SSE not present amongst the CPU's xstate features: 0x%llx.\n", xfeatures_mask
);
738 xfeatures_mask
&= fpu__get_supported_xfeatures_mask();
740 /* Enable xstate instructions to be able to continue with initialization: */
741 fpu__init_cpu_xstate();
742 err
= init_xstate_size();
747 * Update info used for ptrace frames; use standard-format size and no
748 * supervisor xstates:
750 update_regset_xstate_info(fpu_user_xstate_size
, xfeatures_mask
& ~XFEATURE_MASK_SUPERVISOR
);
752 fpu__init_prepare_fx_sw_frame();
753 setup_init_fpu_buf();
755 print_xstate_offset_size();
757 pr_info("x86/fpu: Enabled xstate features 0x%llx, context size is %d bytes, using '%s' format.\n",
759 fpu_kernel_xstate_size
,
760 boot_cpu_has(X86_FEATURE_XSAVES
) ? "compacted" : "standard");
764 /* something went wrong, try to boot without any XSAVE support */
765 fpu__init_disable_system_xstate();
769 * Restore minimal FPU state after suspend:
771 void fpu__resume_cpu(void)
774 * Restore XCR0 on xsave capable CPUs:
776 if (boot_cpu_has(X86_FEATURE_XSAVE
))
777 xsetbv(XCR_XFEATURE_ENABLED_MASK
, xfeatures_mask
);
781 * Given an xstate feature mask, calculate where in the xsave
782 * buffer the state is. Callers should ensure that the buffer
785 * Note: does not work for compacted buffers.
787 void *__raw_xsave_addr(struct xregs_state
*xsave
, int xstate_feature_mask
)
789 int feature_nr
= fls64(xstate_feature_mask
) - 1;
791 if (!xfeature_enabled(feature_nr
)) {
796 return (void *)xsave
+ xstate_comp_offsets
[feature_nr
];
799 * Given the xsave area and a state inside, this function returns the
800 * address of the state.
802 * This is the API that is called to get xstate address in either
803 * standard format or compacted format of xsave area.
805 * Note that if there is no data for the field in the xsave buffer
806 * this will return NULL.
809 * xstate: the thread's storage area for all FPU data
810 * xstate_feature: state which is defined in xsave.h (e.g.
811 * XFEATURE_MASK_FP, XFEATURE_MASK_SSE, etc...)
813 * address of the state in the xsave area, or NULL if the
814 * field is not present in the xsave buffer.
816 void *get_xsave_addr(struct xregs_state
*xsave
, int xstate_feature
)
819 * Do we even *have* xsave state?
821 if (!boot_cpu_has(X86_FEATURE_XSAVE
))
825 * We should not ever be requesting features that we
826 * have not enabled. Remember that pcntxt_mask is
827 * what we write to the XCR0 register.
829 WARN_ONCE(!(xfeatures_mask
& xstate_feature
),
830 "get of unsupported state");
832 * This assumes the last 'xsave*' instruction to
833 * have requested that 'xstate_feature' be saved.
834 * If it did not, we might be seeing and old value
835 * of the field in the buffer.
837 * This can happen because the last 'xsave' did not
838 * request that this feature be saved (unlikely)
839 * or because the "init optimization" caused it
842 if (!(xsave
->header
.xfeatures
& xstate_feature
))
845 return __raw_xsave_addr(xsave
, xstate_feature
);
847 EXPORT_SYMBOL_GPL(get_xsave_addr
);
850 * This wraps up the common operations that need to occur when retrieving
851 * data from xsave state. It first ensures that the current task was
852 * using the FPU and retrieves the data in to a buffer. It then calculates
853 * the offset of the requested field in the buffer.
855 * This function is safe to call whether the FPU is in use or not.
857 * Note that this only works on the current task.
860 * @xsave_state: state which is defined in xsave.h (e.g. XFEATURE_MASK_FP,
861 * XFEATURE_MASK_SSE, etc...)
863 * address of the state in the xsave area or NULL if the state
864 * is not present or is in its 'init state'.
866 const void *get_xsave_field_ptr(int xsave_state
)
868 struct fpu
*fpu
= ¤t
->thread
.fpu
;
870 if (!fpu
->fpstate_active
)
873 * fpu__save() takes the CPU's xstate registers
874 * and saves them off to the 'fpu memory buffer.
878 return get_xsave_addr(&fpu
->state
.xsave
, xsave_state
);
881 #ifdef CONFIG_ARCH_HAS_PKEYS
883 #define NR_VALID_PKRU_BITS (CONFIG_NR_PROTECTION_KEYS * 2)
884 #define PKRU_VALID_MASK (NR_VALID_PKRU_BITS - 1)
886 * This will go out and modify PKRU register to set the access
887 * rights for @pkey to @init_val.
889 int arch_set_user_pkey_access(struct task_struct
*tsk
, int pkey
,
890 unsigned long init_val
)
893 int pkey_shift
= (pkey
* PKRU_BITS_PER_PKEY
);
894 u32 new_pkru_bits
= 0;
897 * This check implies XSAVE support. OSPKE only gets
898 * set if we enable XSAVE and we enable PKU in XCR0.
900 if (!boot_cpu_has(X86_FEATURE_OSPKE
))
903 /* Set the bits we need in PKRU: */
904 if (init_val
& PKEY_DISABLE_ACCESS
)
905 new_pkru_bits
|= PKRU_AD_BIT
;
906 if (init_val
& PKEY_DISABLE_WRITE
)
907 new_pkru_bits
|= PKRU_WD_BIT
;
909 /* Shift the bits in to the correct place in PKRU for pkey: */
910 new_pkru_bits
<<= pkey_shift
;
912 /* Get old PKRU and mask off any old bits in place: */
913 old_pkru
= read_pkru();
914 old_pkru
&= ~((PKRU_AD_BIT
|PKRU_WD_BIT
) << pkey_shift
);
916 /* Write old part along with new part: */
917 write_pkru(old_pkru
| new_pkru_bits
);
921 #endif /* ! CONFIG_ARCH_HAS_PKEYS */
924 * Weird legacy quirk: SSE and YMM states store information in the
925 * MXCSR and MXCSR_FLAGS fields of the FP area. That means if the FP
926 * area is marked as unused in the xfeatures header, we need to copy
927 * MXCSR and MXCSR_FLAGS if either SSE or YMM are in use.
929 static inline bool xfeatures_mxcsr_quirk(u64 xfeatures
)
931 if (!(xfeatures
& (XFEATURE_MASK_SSE
|XFEATURE_MASK_YMM
)))
934 if (xfeatures
& XFEATURE_MASK_FP
)
941 * This is similar to user_regset_copyout(), but will not add offset to
942 * the source data pointer or increment pos, count, kbuf, and ubuf.
945 __copy_xstate_to_kernel(void *kbuf
, const void *data
,
946 unsigned int offset
, unsigned int size
, unsigned int size_total
)
948 if (offset
< size_total
) {
949 unsigned int copy
= min(size
, size_total
- offset
);
951 memcpy(kbuf
+ offset
, data
, copy
);
956 * Convert from kernel XSAVES compacted format to standard format and copy
957 * to a kernel-space ptrace buffer.
959 * It supports partial copy but pos always starts from zero. This is called
960 * from xstateregs_get() and there we check the CPU has XSAVES.
962 int copy_xstate_to_kernel(void *kbuf
, struct xregs_state
*xsave
, unsigned int offset_start
, unsigned int size_total
)
964 unsigned int offset
, size
;
965 struct xstate_header header
;
969 * Currently copy_regset_to_user() starts from pos 0:
971 if (unlikely(offset_start
!= 0))
975 * The destination is a ptrace buffer; we put in only user xstates:
977 memset(&header
, 0, sizeof(header
));
978 header
.xfeatures
= xsave
->header
.xfeatures
;
979 header
.xfeatures
&= ~XFEATURE_MASK_SUPERVISOR
;
982 * Copy xregs_state->header:
984 offset
= offsetof(struct xregs_state
, header
);
985 size
= sizeof(header
);
987 __copy_xstate_to_kernel(kbuf
, &header
, offset
, size
, size_total
);
989 for (i
= 0; i
< XFEATURE_MAX
; i
++) {
991 * Copy only in-use xstates:
993 if ((header
.xfeatures
>> i
) & 1) {
994 void *src
= __raw_xsave_addr(xsave
, 1 << i
);
996 offset
= xstate_offsets
[i
];
997 size
= xstate_sizes
[i
];
999 /* The next component has to fit fully into the output buffer: */
1000 if (offset
+ size
> size_total
)
1003 __copy_xstate_to_kernel(kbuf
, src
, offset
, size
, size_total
);
1008 if (xfeatures_mxcsr_quirk(header
.xfeatures
)) {
1009 offset
= offsetof(struct fxregs_state
, mxcsr
);
1010 size
= MXCSR_AND_FLAGS_SIZE
;
1011 __copy_xstate_to_kernel(kbuf
, &xsave
->i387
.mxcsr
, offset
, size
, size_total
);
1015 * Fill xsave->i387.sw_reserved value for ptrace frame:
1017 offset
= offsetof(struct fxregs_state
, sw_reserved
);
1018 size
= sizeof(xstate_fx_sw_bytes
);
1020 __copy_xstate_to_kernel(kbuf
, xstate_fx_sw_bytes
, offset
, size
, size_total
);
1026 __copy_xstate_to_user(void __user
*ubuf
, const void *data
, unsigned int offset
, unsigned int size
, unsigned int size_total
)
1031 if (offset
< size_total
) {
1032 unsigned int copy
= min(size
, size_total
- offset
);
1034 if (__copy_to_user(ubuf
+ offset
, data
, copy
))
1041 * Convert from kernel XSAVES compacted format to standard format and copy
1042 * to a user-space buffer. It supports partial copy but pos always starts from
1043 * zero. This is called from xstateregs_get() and there we check the CPU
1046 int copy_xstate_to_user(void __user
*ubuf
, struct xregs_state
*xsave
, unsigned int offset_start
, unsigned int size_total
)
1048 unsigned int offset
, size
;
1050 struct xstate_header header
;
1053 * Currently copy_regset_to_user() starts from pos 0:
1055 if (unlikely(offset_start
!= 0))
1059 * The destination is a ptrace buffer; we put in only user xstates:
1061 memset(&header
, 0, sizeof(header
));
1062 header
.xfeatures
= xsave
->header
.xfeatures
;
1063 header
.xfeatures
&= ~XFEATURE_MASK_SUPERVISOR
;
1066 * Copy xregs_state->header:
1068 offset
= offsetof(struct xregs_state
, header
);
1069 size
= sizeof(header
);
1071 ret
= __copy_xstate_to_user(ubuf
, &header
, offset
, size
, size_total
);
1075 for (i
= 0; i
< XFEATURE_MAX
; i
++) {
1077 * Copy only in-use xstates:
1079 if ((header
.xfeatures
>> i
) & 1) {
1080 void *src
= __raw_xsave_addr(xsave
, 1 << i
);
1082 offset
= xstate_offsets
[i
];
1083 size
= xstate_sizes
[i
];
1085 /* The next component has to fit fully into the output buffer: */
1086 if (offset
+ size
> size_total
)
1089 ret
= __copy_xstate_to_user(ubuf
, src
, offset
, size
, size_total
);
1096 if (xfeatures_mxcsr_quirk(header
.xfeatures
)) {
1097 offset
= offsetof(struct fxregs_state
, mxcsr
);
1098 size
= MXCSR_AND_FLAGS_SIZE
;
1099 __copy_xstate_to_user(ubuf
, &xsave
->i387
.mxcsr
, offset
, size
, size_total
);
1103 * Fill xsave->i387.sw_reserved value for ptrace frame:
1105 offset
= offsetof(struct fxregs_state
, sw_reserved
);
1106 size
= sizeof(xstate_fx_sw_bytes
);
1108 ret
= __copy_xstate_to_user(ubuf
, xstate_fx_sw_bytes
, offset
, size
, size_total
);
1116 * Convert from a ptrace standard-format kernel buffer to kernel XSAVES format
1117 * and copy to the target thread. This is called from xstateregs_set() and
1118 * there we check the CPU has XSAVES and a whole standard-sized buffer
1121 int copy_kernel_to_xstate(struct xregs_state
*xsave
, const void *kbuf
)
1123 unsigned int offset
, size
;
1126 u64 allowed_features
;
1128 offset
= offsetof(struct xregs_state
, header
);
1129 size
= sizeof(xfeatures
);
1131 memcpy(&xfeatures
, kbuf
+ offset
, size
);
1134 * Reject if the user sets any disabled or supervisor features:
1136 allowed_features
= xfeatures_mask
& ~XFEATURE_MASK_SUPERVISOR
;
1138 if (xfeatures
& ~allowed_features
)
1141 for (i
= 0; i
< XFEATURE_MAX
; i
++) {
1142 u64 mask
= ((u64
)1 << i
);
1144 if (xfeatures
& mask
) {
1145 void *dst
= __raw_xsave_addr(xsave
, 1 << i
);
1147 offset
= xstate_offsets
[i
];
1148 size
= xstate_sizes
[i
];
1150 memcpy(dst
, kbuf
+ offset
, size
);
1154 if (xfeatures_mxcsr_quirk(xfeatures
)) {
1155 offset
= offsetof(struct fxregs_state
, mxcsr
);
1156 size
= MXCSR_AND_FLAGS_SIZE
;
1157 memcpy(&xsave
->i387
.mxcsr
, kbuf
+ offset
, size
);
1161 * The state that came in from userspace was user-state only.
1162 * Mask all the user states out of 'xfeatures':
1164 xsave
->header
.xfeatures
&= XFEATURE_MASK_SUPERVISOR
;
1167 * Add back in the features that came in from userspace:
1169 xsave
->header
.xfeatures
|= xfeatures
;
1175 * Convert from a ptrace standard-format user-space buffer to kernel XSAVES format
1176 * and copy to the target thread. This is called from xstateregs_set() and
1177 * there we check the CPU has XSAVES and a whole standard-sized buffer
1180 int copy_user_to_xstate(struct xregs_state
*xsave
, const void __user
*ubuf
)
1182 unsigned int offset
, size
;
1185 u64 allowed_features
;
1187 offset
= offsetof(struct xregs_state
, header
);
1188 size
= sizeof(xfeatures
);
1190 if (__copy_from_user(&xfeatures
, ubuf
+ offset
, size
))
1194 * Reject if the user sets any disabled or supervisor features:
1196 allowed_features
= xfeatures_mask
& ~XFEATURE_MASK_SUPERVISOR
;
1198 if (xfeatures
& ~allowed_features
)
1201 for (i
= 0; i
< XFEATURE_MAX
; i
++) {
1202 u64 mask
= ((u64
)1 << i
);
1204 if (xfeatures
& mask
) {
1205 void *dst
= __raw_xsave_addr(xsave
, 1 << i
);
1207 offset
= xstate_offsets
[i
];
1208 size
= xstate_sizes
[i
];
1210 if (__copy_from_user(dst
, ubuf
+ offset
, size
))
1215 if (xfeatures_mxcsr_quirk(xfeatures
)) {
1216 offset
= offsetof(struct fxregs_state
, mxcsr
);
1217 size
= MXCSR_AND_FLAGS_SIZE
;
1218 if (__copy_from_user(&xsave
->i387
.mxcsr
, ubuf
+ offset
, size
))
1223 * The state that came in from userspace was user-state only.
1224 * Mask all the user states out of 'xfeatures':
1226 xsave
->header
.xfeatures
&= XFEATURE_MASK_SUPERVISOR
;
1229 * Add back in the features that came in from userspace:
1231 xsave
->header
.xfeatures
|= xfeatures
;