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Groups > linux.kernel > #1283502

[PATCH 29/34] x86: separate out LDT init from context init

From Dave Hansen <dave@sr71.net>
Newsgroups linux.kernel
Subject [PATCH 29/34] x86: separate out LDT init from context init
Date 2015-12-04 02:20 +0100
Message-ID <qBNct-4nR-19@gated-at.bofh.it> (permalink)
References <qBNct-4nR-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

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From: Dave Hansen <dave.hansen@linux.intel.com>

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@linux.intel.com>
---

 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~init-ldt-extricate arch/x86/include/asm/mmu_context.h
--- a/arch/x86/include/asm/mmu_context.h~init-ldt-extricate	2015-12-03 16:21:31.585941570 -0800
+++ b/arch/x86/include/asm/mmu_context.h	2015-12-03 16:21:31.590941797 -0800
@@ -53,15 +53,15 @@ 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)
@@ -105,6 +105,17 @@ 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~init-ldt-extricate arch/x86/kernel/ldt.c
--- a/arch/x86/kernel/ldt.c~init-ldt-extricate	2015-12-03 16:21:31.587941660 -0800
+++ b/arch/x86/kernel/ldt.c	2015-12-03 16:21:31.590941797 -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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Thread

[PATCH 00/34] x86: Memory Protection Keys (v5) Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
  [PATCH 09/34] x86, pkeys: store protection in high VMA flags Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
    Re: [PATCH 09/34] x86, pkeys: store protection in high VMA flags Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 15:20 +0100
  [PATCH 32/34] x86, pkeys: add pkey set/get syscalls Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
  [PATCH 29/34] x86: separate out LDT init from context init Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
  [PATCH 31/34] x86, pkeys: allocation/free syscalls Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
  [PATCH 12/34] signals, pkeys: notify userspace about protection key faults Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
  [PATCH 20/34] x86, pkeys: differentiate instruction fetches Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
    Re: [PATCH 20/34] x86, pkeys: differentiate instruction fetches Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 19:20 +0100
  [PATCH 19/34] x86, pkeys: optimize fault handling in access_error() Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
    Re: [PATCH 19/34] x86, pkeys: optimize fault handling in  access_error() Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 19:20 +0100
  [PATCH 18/34] mm: add gup flag to indicate "foreign" mm access Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
  [PATCH 27/34] x86, pkeys: make mprotect_key() mask off additional vm_flags Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
    Re: [PATCH 27/34] x86, pkeys: make mprotect_key() mask off additional  vm_flags Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 19:50 +0100
  [PATCH 23/34] x86, pkeys: add Kconfig prompt to existing config option Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
    Re: [PATCH 23/34] x86, pkeys: add Kconfig prompt to existing config  option Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 19:30 +0100
  [PATCH 25/34] x86, pkeys: add arch_validate_pkey() Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
    Re: [PATCH 25/34] x86, pkeys: add arch_validate_pkey() Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 19:50 +0100
  [PATCH 33/34] x86, pkeys: actually enable Memory Protection Keys in CPU Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
  [PATCH 26/34] mm: implement new mprotect_key() system call Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
    Re: [PATCH 26/34] mm: implement new mprotect_key() system call "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com> - 2015-12-05 08:00 +0100
      Re: [PATCH 26/34] mm: implement new mprotect_key() system call Dave Hansen <dave@sr71.net> - 2015-12-07 17:50 +0100
        Re: [PATCH 26/34] mm: implement new mprotect_key() system call "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com> - 2015-12-09 12:10 +0100
          Re: [PATCH 26/34] mm: implement new mprotect_key() system call Dave Hansen <dave@sr71.net> - 2015-12-09 16:50 +0100
            Re: [PATCH 26/34] mm: implement new mprotect_key() system call "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com> - 2015-12-09 17:50 +0100
              Re: [PATCH 26/34] mm: implement new mprotect_key() system call Dave Hansen <dave@sr71.net> - 2015-12-09 18:10 +0100
                Re: [PATCH 26/34] mm: implement new mprotect_key() system call "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com> - 2015-12-11 21:20 +0100
  [PATCH 24/34] mm, multi-arch: pass a protection key in to calc_vm_flag_bits() Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
  [PATCH 22/34] x86, pkeys: dump PTE pkey in /proc/pid/smaps Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
  [PATCH 14/34] x86, pkeys: add functions to fetch PKRU Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
    Re: [PATCH 14/34] x86, pkeys: add functions to fetch PKRU Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 16:20 +0100
  [PATCH 11/34] x86, pkeys: pass VMA down in to fault signal generation code Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
  [PATCH 02/34] x86, fpu: add placeholder for Processor Trace XSAVE state Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
  [PATCH 16/34] x86, mm: simplify get_user_pages() PTE bit handling Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
    Re: [PATCH 16/34] x86, mm: simplify get_user_pages() PTE bit  handling Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 19:10 +0100
      Re: [PATCH 16/34] x86, mm: simplify get_user_pages() PTE bit handling Dave Hansen <dave@sr71.net> - 2015-12-08 19:40 +0100
  [PATCH 10/34] x86, pkeys: arch-specific protection bits Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
    Re: [PATCH 10/34] x86, pkeys: arch-specific protection bitsy Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 16:20 +0100
      Re: [PATCH 10/34] x86, pkeys: arch-specific protection bitsy Dave Hansen <dave@sr71.net> - 2015-12-08 17:40 +0100
        Re: [PATCH 10/34] x86, pkeys: arch-specific protection bitsy Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 18:30 +0100
          Re: [PATCH 10/34] x86, pkeys: arch-specific protection bitsy Dave Hansen <dave@sr71.net> - 2015-12-08 19:10 +0100
            Re: [PATCH 10/34] x86, pkeys: arch-specific protection bitsy Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 19:40 +0100
            Re: [PATCH 10/34] x86, pkeys: arch-specific protection bitsy Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 19:40 +0100
  [PATCH 06/34] x86, pkeys: add PKRU xsave fields and data structure(s) Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
  [PATCH 05/34] x86, pkeys: define new CR4 bit Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
  [PATCH 01/34] mm, gup: introduce concept of "foreign" get_user_pages() Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
  [PATCH 17/34] x86, pkeys: check VMAs and PTEs for protection keys Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
    Re: [PATCH 17/34] x86, pkeys: check VMAs and PTEs for protection  keys Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 19:20 +0100
  [PATCH 13/34] x86, pkeys: fill in pkey field in siginfo Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
  [PATCH 08/34] x86, pkeys: new page fault error code bit: PF_PK Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
  [PATCH 07/34] x86, pkeys: PTE bits for storing protection key Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
  [PATCH 04/34] x86, pkeys: cpuid bit definition Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
  Re: [PATCH 00/34] x86: Memory Protection Keys (v5) Dave Hansen <dave@sr71.net> - 2015-12-05 00:40 +0100
    Re: [PATCH 00/34] x86: Memory Protection Keys (v5) Andy Lutomirski <luto@amacapital.net> - 2015-12-11 21:20 +0100
  Re: [PATCH 00/34] x86: Memory Protection Keys (v5) Andy Lutomirski <luto@amacapital.net> - 2015-12-05 00:40 +0100

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