Commit 39a0526f authored by Dave Hansen's avatar Dave Hansen Committed by Ingo Molnar
Browse files

x86/mm: Factor out LDT init from context init 



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: default avatarDave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20160212210234.DB34FCC5@viggo.jf.intel.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 66d37570

arch/x86/include/asm/mmu_context.h

+16 −5
Original line number Diff line number Diff line
@@ -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,

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 mm_struct *mm, struct task_struct *tsk) 
#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)

{

arch/x86/kernel/ldt.c

+2 −2
Original line number Diff line number Diff line
@@ -103,7 +103,7 @@ static void free_ldt_struct(struct ldt_struct *ldt) 
 * 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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