f9281648ec
This will let us sprinkle sanity checks around the kernel without making too much of a mess. Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Denys Vlasenko <vda.linux@googlemail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: paulmck@linux.vnet.ibm.com Link: http://lkml.kernel.org/r/5da41fb2ceb29eac671f427c67040401ba2a1fa0.1435952415.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
50 lines
1.3 KiB
C
50 lines
1.3 KiB
C
#ifndef _LINUX_CONTEXT_TRACKING_STATE_H
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#define _LINUX_CONTEXT_TRACKING_STATE_H
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#include <linux/percpu.h>
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#include <linux/static_key.h>
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struct context_tracking {
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/*
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* When active is false, probes are unset in order
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* to minimize overhead: TIF flags are cleared
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* and calls to user_enter/exit are ignored. This
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* may be further optimized using static keys.
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*/
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bool active;
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int recursion;
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enum ctx_state {
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CONTEXT_DISABLED = -1, /* returned by ct_state() if unknown */
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CONTEXT_KERNEL = 0,
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CONTEXT_USER,
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CONTEXT_GUEST,
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} state;
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};
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#ifdef CONFIG_CONTEXT_TRACKING
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extern struct static_key context_tracking_enabled;
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DECLARE_PER_CPU(struct context_tracking, context_tracking);
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static inline bool context_tracking_is_enabled(void)
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{
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return static_key_false(&context_tracking_enabled);
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}
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static inline bool context_tracking_cpu_is_enabled(void)
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{
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return __this_cpu_read(context_tracking.active);
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}
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static inline bool context_tracking_in_user(void)
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{
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return __this_cpu_read(context_tracking.state) == CONTEXT_USER;
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}
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#else
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static inline bool context_tracking_in_user(void) { return false; }
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static inline bool context_tracking_active(void) { return false; }
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static inline bool context_tracking_is_enabled(void) { return false; }
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static inline bool context_tracking_cpu_is_enabled(void) { return false; }
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#endif /* CONFIG_CONTEXT_TRACKING */
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#endif
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