From 7e9916040b3020d0f36d68bb7512e3b80b623097 Mon Sep 17 00:00:00 2001
From: Roland McGrath <roland@redhat.com>
Date: Wed, 30 Jan 2008 13:30:54 +0100
Subject: x86: debugctlmsr context switch

This adds low-level support for a per-thread value of MSR_IA32_DEBUGCTLMSR.
The per-thread value is switched in when TIF_DEBUGCTLMSR is set.

Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 include/asm-x86/processor_32.h   | 2 ++
 include/asm-x86/processor_64.h   | 2 ++
 include/asm-x86/thread_info_32.h | 6 ++++--
 include/asm-x86/thread_info_64.h | 4 +++-
 4 files changed, 11 insertions(+), 3 deletions(-)

(limited to 'include/asm-x86')

diff --git a/include/asm-x86/processor_32.h b/include/asm-x86/processor_32.h
index 2540bf8d5724..3c67eacb3168 100644
--- a/include/asm-x86/processor_32.h
+++ b/include/asm-x86/processor_32.h
@@ -368,6 +368,8 @@ struct thread_struct {
  	unsigned long	iopl;
 /* max allowed port in the bitmap, in bytes: */
 	unsigned long	io_bitmap_max;
+/* MSR_IA32_DEBUGCTLMSR value to switch in if TIF_DEBUGCTLMSR is set.  */
+	unsigned long	debugctlmsr;
 };
 
 #define INIT_THREAD  {							\
diff --git a/include/asm-x86/processor_64.h b/include/asm-x86/processor_64.h
index 20d8935d141a..e7bea4fed642 100644
--- a/include/asm-x86/processor_64.h
+++ b/include/asm-x86/processor_64.h
@@ -238,6 +238,8 @@ struct thread_struct {
 	int		ioperm;
 	unsigned long	*io_bitmap_ptr;
 	unsigned io_bitmap_max;
+/* MSR_IA32_DEBUGCTLMSR value to switch in if TIF_DEBUGCTLMSR is set.  */
+	unsigned long	debugctlmsr;
 /* cached TLS descriptors. */
 	u64 tls_array[GDT_ENTRY_TLS_ENTRIES];
 } __attribute__((aligned(16)));
diff --git a/include/asm-x86/thread_info_32.h b/include/asm-x86/thread_info_32.h
index 009ecc6ad38b..306fc80800e1 100644
--- a/include/asm-x86/thread_info_32.h
+++ b/include/asm-x86/thread_info_32.h
@@ -139,6 +139,7 @@ static inline struct thread_info *current_thread_info(void)
 #define TIF_FREEZE		19	/* is freezing for suspend */
 #define TIF_NOTSC		20	/* TSC is not accessible in userland */
 #define TIF_FORCED_TF		21	/* true if TF in eflags artificially */
+#define TIF_DEBUGCTLMSR		22	/* uses thread_struct.debugctlmsr */
 
 #define _TIF_SYSCALL_TRACE	(1<<TIF_SYSCALL_TRACE)
 #define _TIF_SIGPENDING		(1<<TIF_SIGPENDING)
@@ -155,6 +156,7 @@ static inline struct thread_info *current_thread_info(void)
 #define _TIF_FREEZE		(1<<TIF_FREEZE)
 #define _TIF_NOTSC		(1<<TIF_NOTSC)
 #define _TIF_FORCED_TF		(1<<TIF_FORCED_TF)
+#define _TIF_DEBUGCTLMSR	(1<<TIF_DEBUGCTLMSR)
 
 /* work to do on interrupt/exception return */
 #define _TIF_WORK_MASK \
@@ -164,8 +166,8 @@ 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_NEXT (_TIF_IO_BITMAP | _TIF_NOTSC | _TIF_DEBUG)
-#define _TIF_WORK_CTXSW_PREV (_TIF_IO_BITMAP | _TIF_NOTSC)
+#define _TIF_WORK_CTXSW_NEXT (_TIF_IO_BITMAP | _TIF_NOTSC | _TIF_DEBUG | _TIF_DEBUGCTLMSR)
+#define _TIF_WORK_CTXSW_PREV (_TIF_IO_BITMAP | _TIF_NOTSC | _TIF_DEBUGCTLMSR)
 
 /*
  * Thread-synchronous status.
diff --git a/include/asm-x86/thread_info_64.h b/include/asm-x86/thread_info_64.h
index e0f41b3deced..ee35fd12b541 100644
--- a/include/asm-x86/thread_info_64.h
+++ b/include/asm-x86/thread_info_64.h
@@ -122,6 +122,7 @@ static inline struct thread_info *stack_thread_info(void)
 #define TIF_IO_BITMAP		22	/* uses I/O bitmap */
 #define TIF_FREEZE		23	/* is freezing for suspend */
 #define TIF_FORCED_TF		24	/* true if TF in eflags artificially */
+#define TIF_DEBUGCTLMSR		25	/* uses thread_struct.debugctlmsr */
 
 #define _TIF_SYSCALL_TRACE	(1<<TIF_SYSCALL_TRACE)
 #define _TIF_SIGPENDING		(1<<TIF_SIGPENDING)
@@ -140,6 +141,7 @@ static inline struct thread_info *stack_thread_info(void)
 #define _TIF_IO_BITMAP		(1<<TIF_IO_BITMAP)
 #define _TIF_FREEZE		(1<<TIF_FREEZE)
 #define _TIF_FORCED_TF		(1<<TIF_FORCED_TF)
+#define _TIF_DEBUGCTLMSR	(1<<TIF_DEBUGCTLMSR)
 
 /* work to do on interrupt/exception return */
 #define _TIF_WORK_MASK \
@@ -151,7 +153,7 @@ static inline struct thread_info *stack_thread_info(void)
 	(_TIF_SIGPENDING|_TIF_SINGLESTEP|_TIF_MCE_NOTIFY|_TIF_HRTICK_RESCHED)
 
 /* flags to check in __switch_to() */
-#define _TIF_WORK_CTXSW (_TIF_DEBUG|_TIF_IO_BITMAP)
+#define _TIF_WORK_CTXSW (_TIF_DEBUG|_TIF_IO_BITMAP|_TIF_DEBUGCTLMSR)
 
 #define PREEMPT_ACTIVE     0x10000000
 
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