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authorRoland McGrath <roland@redhat.com>2008-01-30 13:30:54 +0100
committerIngo Molnar <mingo@elte.hu>2008-01-30 13:30:54 +0100
commit7e9916040b3020d0f36d68bb7512e3b80b623097 (patch)
tree7c391bcdb7a5d917b54ae968304e8a951997e16e /arch
parent0a049bb0ab807b4a95dce9cd0b603c01c199a287 (diff)
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>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/process_32.c6
-rw-r--r--arch/x86/kernel/process_64.c3
2 files changed, 8 insertions, 1 deletions
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index d9905c9d0fd..d5462f228da 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -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);
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index f7356e5517f..ae5eca17aa3 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -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);