From: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
The arch-specific mm_context_t is a great place to put
protection-key allocation state.
But, we need to initialize the allocation state because pkey 0 is
always "allocated". All of the runtime initialization of
mm_context_t is done in *_ldt() manipulation functions. This
renames the existing LDT functions like this:
init_new_context() -> init_new_context_ldt()
destroy_context() -> destroy_context_ldt()
and makes init_new_context() and destroy_context() available for
generic use.
Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
b/arch/x86/include/asm/mmu_context.h | 21 ++++++++++++++++-----
b/arch/x86/kernel/ldt.c | 4 ++--
2 files changed, 18 insertions(+), 7 deletions(-)
diff -puN arch/x86/include/asm/mmu_context.h~pkeys-72-init-ldt-extricate arch/x86/include/asm/mmu_context.h
--- a/arch/x86/include/asm/mmu_context.h~pkeys-72-init-ldt-extricate 2016-01-06 15:50:15.004579524 -0800
+++ b/arch/x86/include/asm/mmu_context.h 2016-01-06 15:50:15.008579705 -0800
@@ -52,15 +52,15 @@ struct ldt_struct {
/*
* Used for LDT copy/destruction.
*/
-int init_new_context(struct task_struct *tsk, struct mm_struct *mm);
-void destroy_context(struct mm_struct *mm);
+int init_new_context_ldt(struct task_struct *tsk, struct mm_struct *mm);
+void destroy_context_ldt(struct mm_struct *mm);
#else /* CONFIG_MODIFY_LDT_SYSCALL */
-static inline int init_new_context(struct task_struct *tsk,
- struct mm_struct *mm)
+static inline int init_new_context_ldt(struct task_struct *tsk,
+ struct mm_struct *mm)
{
return 0;
}
-static inline void destroy_context(struct mm_struct *mm) {}
+static inline void destroy_context_ldt(struct mm_struct *mm) {}
#endif
static inline void load_mm_ldt(struct mm_struct *mm)
@@ -104,6 +104,17 @@ static inline void enter_lazy_tlb(struct
#endif
}
+static inline int init_new_context(struct task_struct *tsk,
+ struct mm_struct *mm)
+{
+ init_new_context_ldt(tsk, mm);
+ return 0;
+}
+static inline void destroy_context(struct mm_struct *mm)
+{
+ destroy_context_ldt(mm);
+}
+
static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
struct task_struct *tsk)
{
diff -puN arch/x86/kernel/ldt.c~pkeys-72-init-ldt-extricate arch/x86/kernel/ldt.c
--- a/arch/x86/kernel/ldt.c~pkeys-72-init-ldt-extricate 2016-01-06 15:50:15.005579569 -0800
+++ b/arch/x86/kernel/ldt.c 2016-01-06 15:50:15.009579749 -0800
@@ -103,7 +103,7 @@ static void free_ldt_struct(struct ldt_s
* we do not have to muck with descriptors here, that is
* done in switch_mm() as needed.
*/
-int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
+int init_new_context_ldt(struct task_struct *tsk, struct mm_struct *mm)
{
struct ldt_struct *new_ldt;
struct mm_struct *old_mm;
@@ -144,7 +144,7 @@ out_unlock:
*
* 64bit: Don't touch the LDT register - we're already in the next thread.
*/
-void destroy_context(struct mm_struct *mm)
+void destroy_context_ldt(struct mm_struct *mm)
{
free_ldt_struct(mm->context.ldt);
mm->context.ldt = NULL;
_
--
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