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| author | Dave Hansen <dave.hansen@linux.intel.com> | 2016-06-01 17:42:20 (GMT) |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-06-08 11:33:33 (GMT) |
| commit | d1898b733619bd46194bd25aa6452d238ff2dc4e (patch) | |
| tree | 4cc10df3594b68becae9a7dac03e35025aa5c7d1 /arch/x86/include/asm/fpu | |
| parent | c8ae067f2635be0f8c7e5db1bb74b757d623e05b (diff) | |
| download | linux-d1898b733619bd46194bd25aa6452d238ff2dc4e.tar.xz | |
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 (limited to 'arch/x86/include/asm/fpu')
| -rw-r--r-- | arch/x86/include/asm/fpu/internal.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index 31ac8e6..116b583 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -18,6 +18,7 @@ #include <asm/fpu/api.h> #include <asm/fpu/xstate.h> #include <asm/cpufeature.h> +#include <asm/trace/fpu.h> /* * High level FPU state handling functions: @@ -524,6 +525,7 @@ static inline void __fpregs_deactivate(struct fpu *fpu) fpu->fpregs_active = 0; this_cpu_write(fpu_fpregs_owner_ctx, NULL); + trace_x86_fpu_regs_deactivated(fpu); } /* Must be paired with a 'clts' (fpregs_activate_hw()) before! */ @@ -533,6 +535,7 @@ static inline void __fpregs_activate(struct fpu *fpu) fpu->fpregs_active = 1; this_cpu_write(fpu_fpregs_owner_ctx, fpu); + trace_x86_fpu_regs_activated(fpu); } /* @@ -604,11 +607,13 @@ switch_fpu_prepare(struct fpu *old_fpu, struct fpu *new_fpu, int cpu) /* But leave fpu_fpregs_owner_ctx! */ old_fpu->fpregs_active = 0; + trace_x86_fpu_regs_deactivated(old_fpu); /* Don't change CR0.TS if we just switch! */ if (fpu.preload) { new_fpu->counter++; __fpregs_activate(new_fpu); + trace_x86_fpu_regs_activated(new_fpu); prefetch(&new_fpu->state); } else { __fpregs_deactivate_hw(); |