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x86: debugctlmsr context switch

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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>
This commit is contained in:
Roland McGrath 2008-01-30 13:30:54 +01:00 committed by Ingo Molnar
parent 0a049bb0ab
commit 7e9916040b
6 changed files with 19 additions and 4 deletions
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6
arch/x86/kernel/process_32.c
View File

@ -602,10 +602,14 @@ static noinline void
__switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p,
struct tss_struct *tss)
{
struct thread_struct *next;
struct thread_struct *prev, *next;
prev = &prev_p->thread;
next = &next_p->thread;
if (next->debugctlmsr != prev->debugctlmsr)
wrmsr(MSR_IA32_DEBUGCTLMSR, next->debugctlmsr, 0);
if (test_tsk_thread_flag(next_p, TIF_DEBUG)) {
set_debugreg(next->debugreg[0], 0);
set_debugreg(next->debugreg[1], 1);

3
arch/x86/kernel/process_64.c
View File

@ -555,6 +555,9 @@ static inline void __switch_to_xtra(struct task_struct *prev_p,
prev = &prev_p->thread,
next = &next_p->thread;
if (next->debugctlmsr != prev->debugctlmsr)
wrmsrl(MSR_IA32_DEBUGCTLMSR, next->debugctlmsr);
if (test_tsk_thread_flag(next_p, TIF_DEBUG)) {
loaddebug(next, 0);
loaddebug(next, 1);

2
include/asm-x86/processor_32.h
View File

@ -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 { \

2
include/asm-x86/processor_64.h
View File

@ -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)));

6
include/asm-x86/thread_info_32.h
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@ -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.

4
include/asm-x86/thread_info_64.h
View File

@ -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