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Diffstat (limited to 'arch/x86/kernel/process_32.c')
-rw-r--r--arch/x86/kernel/process_32.c37
1 files changed, 25 insertions, 12 deletions
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 5cec8a75a4e8..496ea3110aa2 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -484,20 +484,13 @@ int set_tsc_mode(unsigned int val)
return 0;
}
-static noinline void
-__switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p,
- struct tss_struct *tss)
+#ifdef CONFIG_X86_DS
+static int update_debugctl(struct thread_struct *prev,
+ struct thread_struct *next, unsigned long debugctl)
{
- struct thread_struct *prev, *next;
- unsigned long debugctl;
- unsigned long ds_prev = 0, ds_next = 0;
+ unsigned long ds_prev = 0;
+ unsigned long ds_next = 0;
- prev = &prev_p->thread;
- next = &next_p->thread;
-
- debugctl = prev->debugctlmsr;
-
-#ifdef CONFIG_X86_DS
if (prev->ds_ctx)
ds_prev = (unsigned long)prev->ds_ctx->ds;
if (next->ds_ctx)
@@ -510,8 +503,28 @@ __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p,
update_debugctlmsr(0);
wrmsr(MSR_IA32_DS_AREA, ds_next, 0);
}
+ return debugctl;
+}
+#else
+static int update_debugctl(struct thread_struct *prev,
+ struct thread_struct *next, unsigned long debugctl)
+{
+ return debugctl;
+}
#endif /* CONFIG_X86_DS */
+static noinline void
+__switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p,
+ struct tss_struct *tss)
+{
+ struct thread_struct *prev, *next;
+ unsigned long debugctl;
+
+ prev = &prev_p->thread;
+ next = &next_p->thread;
+
+ debugctl = update_debugctl(prev, next, prev->debugctlmsr);
+
if (next->debugctlmsr != debugctl)
update_debugctlmsr(next->debugctlmsr);