From 7e9916040b3020d0f36d68bb7512e3b80b623097 Mon Sep 17 00:00:00 2001 From: Roland McGrath 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 Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- arch/x86/kernel/process_32.c | 6 +++++- arch/x86/kernel/process_64.c | 3 +++ 2 files changed, 8 insertions(+), 1 deletion(-) (limited to 'arch/x86') diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c index d9905c9d0fd5..d5462f228daf 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 f7356e5517f6..ae5eca17aa3c 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); -- cgit v1.2.3