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14e153ef75
interrupted_kernel_fpu_idle() tries to detect if kernel_fpu_begin() is safe or not. In particular it should obviously deny the nested kernel_fpu_begin() and this logic looks very confusing. If use_eager_fpu() == T we rely on a) __thread_has_fpu() check in interrupted_kernel_fpu_idle(), and b) on the fact that _begin() does __thread_clear_has_fpu(). Otherwise we demand that the interrupted task has no FPU if it is in kernel mode, this works because __kernel_fpu_begin() does clts() and interrupted_kernel_fpu_idle() checks X86_CR0_TS. Add the per-cpu "bool in_kernel_fpu" variable, and change this code to check/set/clear it. This allows to do more cleanups and fixes, see the next changes. The patch also moves WARN_ON_ONCE() under preempt_disable() just to make this_cpu_read() look better, this is not really needed. And in fact I think we should move it into __kernel_fpu_begin(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: matt.fleming@intel.com Cc: bp@suse.de Cc: pbonzini@redhat.com Cc: luto@amacapital.net Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Suresh Siddha <sbsiddha@gmail.com> Link: http://lkml.kernel.org/r/20150115191943.GB27332@redhat.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
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| crypto | ||
| ia32 | ||
| include | ||
| kernel | ||
| kvm | ||
| lguest | ||
| lib | ||
| math-emu | ||
| mm | ||
| net | ||
| oprofile | ||
| pci | ||
| platform | ||
| power | ||
| purgatory | ||
| realmode | ||
| syscalls | ||
| tools | ||
| um | ||
| vdso | ||
| video | ||
| xen | ||
| .gitignore | ||
| Kbuild | ||
| Kconfig | ||
| Kconfig.cpu | ||
| Kconfig.debug | ||
| Makefile | ||
| Makefile_32.cpu | ||
| Makefile.um | ||