From cf99abace7e07dd8491e7093a9a9ef11d48838ed Mon Sep 17 00:00:00 2001
From: Andrea Arcangeli <andrea@cpushare.com>
Date: Sun, 15 Jul 2007 23:41:33 -0700
Subject: make seccomp zerocost in schedule

This follows a suggestion from Chuck Ebbert on how to make seccomp
absolutely zerocost in schedule too.  The only remaining footprint of
seccomp is in terms of the bzImage size that becomes a few bytes (perhaps
even a few kbytes) larger, measure it if you care in the embedded.

Signed-off-by: Andrea Arcangeli <andrea@cpushare.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 include/asm-i386/processor.h   |  4 ++++
 include/asm-i386/thread_info.h |  5 ++++-
 include/linux/seccomp.h        | 10 ----------
 3 files changed, 8 insertions(+), 11 deletions(-)

(limited to 'include')

diff --git a/include/asm-i386/processor.h b/include/asm-i386/processor.h
index 94e0c147c16..422cffef00c 100644
--- a/include/asm-i386/processor.h
+++ b/include/asm-i386/processor.h
@@ -228,6 +228,10 @@ extern int bootloader_type;
 
 #define HAVE_ARCH_PICK_MMAP_LAYOUT
 
+extern void hard_disable_TSC(void);
+extern void disable_TSC(void);
+extern void hard_enable_TSC(void);
+
 /*
  * Size of io_bitmap.
  */
diff --git a/include/asm-i386/thread_info.h b/include/asm-i386/thread_info.h
index 4cb0f91ae64..54424e045e0 100644
--- a/include/asm-i386/thread_info.h
+++ b/include/asm-i386/thread_info.h
@@ -137,6 +137,7 @@ static inline struct thread_info *current_thread_info(void)
 #define TIF_DEBUG		17	/* uses debug registers */
 #define TIF_IO_BITMAP		18	/* uses I/O bitmap */
 #define TIF_FREEZE		19	/* is freezing for suspend */
+#define TIF_NOTSC		20	/* TSC is not accessible in userland */
 
 #define _TIF_SYSCALL_TRACE	(1<<TIF_SYSCALL_TRACE)
 #define _TIF_NOTIFY_RESUME	(1<<TIF_NOTIFY_RESUME)
@@ -151,6 +152,7 @@ static inline struct thread_info *current_thread_info(void)
 #define _TIF_DEBUG		(1<<TIF_DEBUG)
 #define _TIF_IO_BITMAP		(1<<TIF_IO_BITMAP)
 #define _TIF_FREEZE		(1<<TIF_FREEZE)
+#define _TIF_NOTSC		(1<<TIF_NOTSC)
 
 /* work to do on interrupt/exception return */
 #define _TIF_WORK_MASK \
@@ -160,7 +162,8 @@ static inline struct thread_info *current_thread_info(void)
 #define _TIF_ALLWORK_MASK	(0x0000FFFF & ~_TIF_SECCOMP)
 
 /* flags to check in __switch_to() */
-#define _TIF_WORK_CTXSW (_TIF_DEBUG|_TIF_IO_BITMAP)
+#define _TIF_WORK_CTXSW_NEXT (_TIF_IO_BITMAP | _TIF_NOTSC | _TIF_DEBUG)
+#define _TIF_WORK_CTXSW_PREV (_TIF_IO_BITMAP | _TIF_NOTSC)
 
 /*
  * Thread-synchronous status.
diff --git a/include/linux/seccomp.h b/include/linux/seccomp.h
index d708974dbfe..262a8dccfa8 100644
--- a/include/linux/seccomp.h
+++ b/include/linux/seccomp.h
@@ -16,11 +16,6 @@ static inline void secure_computing(int this_syscall)
 		__secure_computing(this_syscall);
 }
 
-static inline int has_secure_computing(struct thread_info *ti)
-{
-	return unlikely(test_ti_thread_flag(ti, TIF_SECCOMP));
-}
-
 extern long prctl_get_seccomp(void);
 extern long prctl_set_seccomp(unsigned long);
 
@@ -29,11 +24,6 @@ extern long prctl_set_seccomp(unsigned long);
 typedef struct { } seccomp_t;
 
 #define secure_computing(x) do { } while (0)
-/* static inline to preserve typechecking */
-static inline int has_secure_computing(struct thread_info *ti)
-{
-	return 0;
-}
 
 static inline long prctl_get_seccomp(void)
 {
-- 
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