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authorDave Hansen <dave.hansen@linux.intel.com>2016-06-01 13:42:20 -0400
committerIngo Molnar <mingo@kernel.org>2016-06-08 07:33:33 -0400
commitd1898b733619bd46194bd25aa6452d238ff2dc4e (patch)
tree4cc10df3594b68becae9a7dac03e35025aa5c7d1
parentc8ae067f2635be0f8c7e5db1bb74b757d623e05b (diff)
x86/fpu: Add tracepoints to dump FPU state at key points
I've been carrying this patch around for a bit and it's helped me solve at least a couple FPU-related bugs. In addition to using it for debugging, I also drug it out because using AVX (and AVX2/AVX-512) can have serious power consequences for a modern core. It's very important to be able to figure out who is using it. It's also insanely useful to go out and see who is using a given feature, like MPX or Memory Protection Keys. If you, for instance, want to find all processes using protection keys, you can do: echo 'xfeatures & 0x200' > filter Since 0x200 is the protection keys feature bit. Note that this touches the KVM code. KVM did a CREATE_TRACE_POINTS and then included a bunch of random headers. If anyone one of those included other tracepoints, it would have defined the *OTHER* tracepoints. That's bogus, so move it to the right place. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Hansen <dave@sr71.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20160601174220.3CDFB90E@viggo.jf.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat
-rw-r--r--arch/x86/include/asm/fpu/internal.h5
-rw-r--r--arch/x86/include/asm/trace/fpu.h119
-rw-r--r--arch/x86/kernel/fpu/core.c18
-rw-r--r--arch/x86/kernel/fpu/signal.c3
-rw-r--r--arch/x86/kvm/x86.c6
5 files changed, 148 insertions, 3 deletions
diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h
index 31ac8e6d9f36..116b58347501 100644
--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -18,6 +18,7 @@
18#include <asm/fpu/api.h> 18#include <asm/fpu/api.h>
19#include <asm/fpu/xstate.h> 19#include <asm/fpu/xstate.h>
20#include <asm/cpufeature.h> 20#include <asm/cpufeature.h>
21#include <asm/trace/fpu.h>
21 22
22/* 23/*
23 * High level FPU state handling functions: 24 * High level FPU state handling functions:
@@ -524,6 +525,7 @@ static inline void __fpregs_deactivate(struct fpu *fpu)
524 525
525 fpu->fpregs_active = 0; 526 fpu->fpregs_active = 0;
526 this_cpu_write(fpu_fpregs_owner_ctx, NULL); 527 this_cpu_write(fpu_fpregs_owner_ctx, NULL);
528 trace_x86_fpu_regs_deactivated(fpu);
527} 529}
528 530
529/* Must be paired with a 'clts' (fpregs_activate_hw()) before! */ 531/* Must be paired with a 'clts' (fpregs_activate_hw()) before! */
@@ -533,6 +535,7 @@ static inline void __fpregs_activate(struct fpu *fpu)
533 535
534 fpu->fpregs_active = 1; 536 fpu->fpregs_active = 1;
535 this_cpu_write(fpu_fpregs_owner_ctx, fpu); 537 this_cpu_write(fpu_fpregs_owner_ctx, fpu);
538 trace_x86_fpu_regs_activated(fpu);
536} 539}
537 540
538/* 541/*
@@ -604,11 +607,13 @@ switch_fpu_prepare(struct fpu *old_fpu, struct fpu *new_fpu, int cpu)
604 607
605 /* But leave fpu_fpregs_owner_ctx! */ 608 /* But leave fpu_fpregs_owner_ctx! */
606 old_fpu->fpregs_active = 0; 609 old_fpu->fpregs_active = 0;
610 trace_x86_fpu_regs_deactivated(old_fpu);
607 611
608 /* Don't change CR0.TS if we just switch! */ 612 /* Don't change CR0.TS if we just switch! */
609 if (fpu.preload) { 613 if (fpu.preload) {
610 new_fpu->counter++; 614 new_fpu->counter++;
611 __fpregs_activate(new_fpu); 615 __fpregs_activate(new_fpu);
616 trace_x86_fpu_regs_activated(new_fpu);
612 prefetch(&new_fpu->state); 617 prefetch(&new_fpu->state);
613 } else { 618 } else {
614 __fpregs_deactivate_hw(); 619 __fpregs_deactivate_hw();
diff --git a/arch/x86/include/asm/trace/fpu.h b/arch/x86/include/asm/trace/fpu.h
new file mode 100644
index 000000000000..9217ab1f5bf6
--- /dev/null
+++ b/arch/x86/include/asm/trace/fpu.h
@@ -0,0 +1,119 @@
1#undef TRACE_SYSTEM
2#define TRACE_SYSTEM x86_fpu
3
4#if !defined(_TRACE_FPU_H) || defined(TRACE_HEADER_MULTI_READ)
5#define _TRACE_FPU_H
6
7#include <linux/tracepoint.h>
8
9DECLARE_EVENT_CLASS(x86_fpu,
10 TP_PROTO(struct fpu *fpu),
11 TP_ARGS(fpu),
12
13 TP_STRUCT__entry(
14 __field(struct fpu *, fpu)
15 __field(bool, fpregs_active)
16 __field(bool, fpstate_active)
17 __field(int, counter)
18 __field(u64, xfeatures)
19 __field(u64, xcomp_bv)
20 ),
21
22 TP_fast_assign(
23 __entry->fpu = fpu;
24 __entry->fpregs_active = fpu->fpregs_active;
25 __entry->fpstate_active = fpu->fpstate_active;
26 __entry->counter = fpu->counter;
27 if (boot_cpu_has(X86_FEATURE_OSXSAVE)) {
28 __entry->xfeatures = fpu->state.xsave.header.xfeatures;
29 __entry->xcomp_bv = fpu->state.xsave.header.xcomp_bv;
30 }
31 ),
32 TP_printk("x86/fpu: %p fpregs_active: %d fpstate_active: %d counter: %d xfeatures: %llx xcomp_bv: %llx",
33 __entry->fpu,
34 __entry->fpregs_active,
35 __entry->fpstate_active,
36 __entry->counter,
37 __entry->xfeatures,
38 __entry->xcomp_bv
39 )
40);
41
42DEFINE_EVENT(x86_fpu, x86_fpu_state,
43 TP_PROTO(struct fpu *fpu),
44 TP_ARGS(fpu)
45);
46
47DEFINE_EVENT(x86_fpu, x86_fpu_before_save,
48 TP_PROTO(struct fpu *fpu),
49 TP_ARGS(fpu)
50);
51
52DEFINE_EVENT(x86_fpu, x86_fpu_after_save,
53 TP_PROTO(struct fpu *fpu),
54 TP_ARGS(fpu)
55);
56
57DEFINE_EVENT(x86_fpu, x86_fpu_before_restore,
58 TP_PROTO(struct fpu *fpu),
59 TP_ARGS(fpu)
60);
61
62DEFINE_EVENT(x86_fpu, x86_fpu_after_restore,
63 TP_PROTO(struct fpu *fpu),
64 TP_ARGS(fpu)
65);
66
67DEFINE_EVENT(x86_fpu, x86_fpu_regs_activated,
68 TP_PROTO(struct fpu *fpu),
69 TP_ARGS(fpu)
70);
71
72DEFINE_EVENT(x86_fpu, x86_fpu_regs_deactivated,
73 TP_PROTO(struct fpu *fpu),
74 TP_ARGS(fpu)
75);
76
77DEFINE_EVENT(x86_fpu, x86_fpu_activate_state,
78 TP_PROTO(struct fpu *fpu),
79 TP_ARGS(fpu)
80);
81
82DEFINE_EVENT(x86_fpu, x86_fpu_deactivate_state,
83 TP_PROTO(struct fpu *fpu),
84 TP_ARGS(fpu)
85);
86
87DEFINE_EVENT(x86_fpu, x86_fpu_init_state,
88 TP_PROTO(struct fpu *fpu),
89 TP_ARGS(fpu)
90);
91
92DEFINE_EVENT(x86_fpu, x86_fpu_dropped,
93 TP_PROTO(struct fpu *fpu),
94 TP_ARGS(fpu)
95);
96
97DEFINE_EVENT(x86_fpu, x86_fpu_copy_src,
98 TP_PROTO(struct fpu *fpu),
99 TP_ARGS(fpu)
100);
101
102DEFINE_EVENT(x86_fpu, x86_fpu_copy_dst,
103 TP_PROTO(struct fpu *fpu),
104 TP_ARGS(fpu)
105);
106
107DEFINE_EVENT(x86_fpu, x86_fpu_xstate_check_failed,
108 TP_PROTO(struct fpu *fpu),
109 TP_ARGS(fpu)
110);
111
112#undef TRACE_INCLUDE_PATH
113#define TRACE_INCLUDE_PATH asm/trace/
114#undef TRACE_INCLUDE_FILE
115#define TRACE_INCLUDE_FILE fpu
116#endif /* _TRACE_FPU_H */
117
118/* This part must be outside protection */
119#include <trace/define_trace.h>
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 97027545a72d..7d564742e499 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -12,6 +12,9 @@
12 12
13#include <linux/hardirq.h> 13#include <linux/hardirq.h>
14 14
15#define CREATE_TRACE_POINTS
16#include <asm/trace/fpu.h>
17
15/* 18/*
16 * Represents the initial FPU state. It's mostly (but not completely) zeroes, 19 * Represents the initial FPU state. It's mostly (but not completely) zeroes,
17 * depending on the FPU hardware format: 20 * depending on the FPU hardware format:
@@ -192,6 +195,7 @@ void fpu__save(struct fpu *fpu)
192 WARN_ON_FPU(fpu != &current->thread.fpu); 195 WARN_ON_FPU(fpu != &current->thread.fpu);
193 196
194 preempt_disable(); 197 preempt_disable();
198 trace_x86_fpu_before_save(fpu);
195 if (fpu->fpregs_active) { 199 if (fpu->fpregs_active) {
196 if (!copy_fpregs_to_fpstate(fpu)) { 200 if (!copy_fpregs_to_fpstate(fpu)) {
197 if (use_eager_fpu()) 201 if (use_eager_fpu())
@@ -200,6 +204,7 @@ void fpu__save(struct fpu *fpu)
200 fpregs_deactivate(fpu); 204 fpregs_deactivate(fpu);
201 } 205 }
202 } 206 }
207 trace_x86_fpu_after_save(fpu);
203 preempt_enable(); 208 preempt_enable();
204} 209}
205EXPORT_SYMBOL_GPL(fpu__save); 210EXPORT_SYMBOL_GPL(fpu__save);
@@ -275,6 +280,9 @@ int fpu__copy(struct fpu *dst_fpu, struct fpu *src_fpu)
275 } 280 }
276 preempt_enable(); 281 preempt_enable();
277 282
283 trace_x86_fpu_copy_src(src_fpu);
284 trace_x86_fpu_copy_dst(dst_fpu);
285
278 return 0; 286 return 0;
279} 287}
280 288
@@ -288,7 +296,9 @@ void fpu__activate_curr(struct fpu *fpu)
288 296
289 if (!fpu->fpstate_active) { 297 if (!fpu->fpstate_active) {
290 fpstate_init(&fpu->state); 298 fpstate_init(&fpu->state);
299 trace_x86_fpu_init_state(fpu);
291 300
301 trace_x86_fpu_activate_state(fpu);
292 /* Safe to do for the current task: */ 302 /* Safe to do for the current task: */
293 fpu->fpstate_active = 1; 303 fpu->fpstate_active = 1;
294 } 304 }
@@ -314,7 +324,9 @@ void fpu__activate_fpstate_read(struct fpu *fpu)
314 } else { 324 } else {
315 if (!fpu->fpstate_active) { 325 if (!fpu->fpstate_active) {
316 fpstate_init(&fpu->state); 326 fpstate_init(&fpu->state);
327 trace_x86_fpu_init_state(fpu);
317 328
329 trace_x86_fpu_activate_state(fpu);
318 /* Safe to do for current and for stopped child tasks: */ 330 /* Safe to do for current and for stopped child tasks: */
319 fpu->fpstate_active = 1; 331 fpu->fpstate_active = 1;
320 } 332 }
@@ -347,7 +359,9 @@ void fpu__activate_fpstate_write(struct fpu *fpu)
347 fpu->last_cpu = -1; 359 fpu->last_cpu = -1;
348 } else { 360 } else {
349 fpstate_init(&fpu->state); 361 fpstate_init(&fpu->state);
362 trace_x86_fpu_init_state(fpu);
350 363
364 trace_x86_fpu_activate_state(fpu);
351 /* Safe to do for stopped child tasks: */ 365 /* Safe to do for stopped child tasks: */
352 fpu->fpstate_active = 1; 366 fpu->fpstate_active = 1;
353 } 367 }
@@ -432,9 +446,11 @@ void fpu__restore(struct fpu *fpu)
432 446
433 /* Avoid __kernel_fpu_begin() right after fpregs_activate() */ 447 /* Avoid __kernel_fpu_begin() right after fpregs_activate() */
434 kernel_fpu_disable(); 448 kernel_fpu_disable();
449 trace_x86_fpu_before_restore(fpu);
435 fpregs_activate(fpu); 450 fpregs_activate(fpu);
436 copy_kernel_to_fpregs(&fpu->state); 451 copy_kernel_to_fpregs(&fpu->state);
437 fpu->counter++; 452 fpu->counter++;
453 trace_x86_fpu_after_restore(fpu);
438 kernel_fpu_enable(); 454 kernel_fpu_enable();
439} 455}
440EXPORT_SYMBOL_GPL(fpu__restore); 456EXPORT_SYMBOL_GPL(fpu__restore);
@@ -463,6 +479,8 @@ void fpu__drop(struct fpu *fpu)
463 479
464 fpu->fpstate_active = 0; 480 fpu->fpstate_active = 0;
465 481
482 trace_x86_fpu_dropped(fpu);
483
466 preempt_enable(); 484 preempt_enable();
467} 485}
468 486
diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
index 31c6a60505e6..c6f2a3cee2c2 100644
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -10,6 +10,7 @@
10#include <asm/fpu/regset.h> 10#include <asm/fpu/regset.h>
11 11
12#include <asm/sigframe.h> 12#include <asm/sigframe.h>
13#include <asm/trace/fpu.h>
13 14
14static struct _fpx_sw_bytes fx_sw_reserved, fx_sw_reserved_ia32; 15static struct _fpx_sw_bytes fx_sw_reserved, fx_sw_reserved_ia32;
15 16
@@ -282,6 +283,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
282 */ 283 */
283 state_size = sizeof(struct fxregs_state); 284 state_size = sizeof(struct fxregs_state);
284 fx_only = 1; 285 fx_only = 1;
286 trace_x86_fpu_xstate_check_failed(fpu);
285 } else { 287 } else {
286 state_size = fx_sw_user.xstate_size; 288 state_size = fx_sw_user.xstate_size;
287 xfeatures = fx_sw_user.xfeatures; 289 xfeatures = fx_sw_user.xfeatures;
@@ -311,6 +313,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
311 if (__copy_from_user(&fpu->state.xsave, buf_fx, state_size) || 313 if (__copy_from_user(&fpu->state.xsave, buf_fx, state_size) ||
312 __copy_from_user(&env, buf, sizeof(env))) { 314 __copy_from_user(&env, buf, sizeof(env))) {
313 fpstate_init(&fpu->state); 315 fpstate_init(&fpu->state);
316 trace_x86_fpu_init_state(fpu);
314 err = -1; 317 err = -1;
315 } else { 318 } else {
316 sanitize_restored_xstate(tsk, &env, xfeatures, fx_only); 319 sanitize_restored_xstate(tsk, &env, xfeatures, fx_only);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 902d9da12392..1ba3b7d3cae9 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -55,9 +55,6 @@
55#include <linux/irqbypass.h> 55#include <linux/irqbypass.h>
56#include <trace/events/kvm.h> 56#include <trace/events/kvm.h>
57 57
58#define CREATE_TRACE_POINTS
59#include "trace.h"
60
61#include <asm/debugreg.h> 58#include <asm/debugreg.h>
62#include <asm/msr.h> 59#include <asm/msr.h>
63#include <asm/desc.h> 60#include <asm/desc.h>
@@ -68,6 +65,9 @@
68#include <asm/div64.h> 65#include <asm/div64.h>
69#include <asm/irq_remapping.h> 66#include <asm/irq_remapping.h>
70 67
68#define CREATE_TRACE_POINTS
69#include "trace.h"
70
71#define MAX_IO_MSRS 256 71#define MAX_IO_MSRS 256
72#define KVM_MAX_MCE_BANKS 32 72#define KVM_MAX_MCE_BANKS 32
73#define KVM_MCE_CAP_SUPPORTED (MCG_CTL_P | MCG_SER_P) 73#define KVM_MCE_CAP_SUPPORTED (MCG_CTL_P | MCG_SER_P)
generated by cgit v1.2.2 (git 2.25.0) at 2025-03-29 02:30:36 -0400