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Groups > linux.kernel > #1390515

[RFC PATCH v2 09/18] livepatch/x86: add TIF_PATCH_PENDING thread flag

From Josh Poimboeuf <jpoimboe@redhat.com>
Newsgroups linux.kernel
Subject [RFC PATCH v2 09/18] livepatch/x86: add TIF_PATCH_PENDING thread flag
Date 2016-04-28 22:50 +0200
Message-ID <rt12P-1W5-37@gated-at.bofh.it> (permalink)
References <rt12N-1W5-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

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Add the TIF_PATCH_PENDING thread flag to enable the new livepatch
per-task consistency model for x86_64.  The bit getting set indicates
the thread has a pending patch which needs to be applied when the thread
exits the kernel.

The bit is placed in the least-significant word of the thread_info flags
so that it gets automatically included in the _TIF_ALLWORK_MASK macro.
This results in exit_to_usermode_loop() and klp_patch_task() getting
called when the bit is set.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
 arch/x86/entry/common.c            | 9 ++++++---
 arch/x86/include/asm/thread_info.h | 2 ++
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index ec138e5..0eaa1d9 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -21,6 +21,7 @@
 #include <linux/context_tracking.h>
 #include <linux/user-return-notifier.h>
 #include <linux/uprobes.h>
+#include <linux/livepatch.h>
 
 #include <asm/desc.h>
 #include <asm/traps.h>
@@ -202,14 +203,13 @@ long syscall_trace_enter(struct pt_regs *regs)
 
 #define EXIT_TO_USERMODE_LOOP_FLAGS				\
 	(_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_UPROBE |	\
-	 _TIF_NEED_RESCHED | _TIF_USER_RETURN_NOTIFY)
+	 _TIF_NEED_RESCHED | _TIF_USER_RETURN_NOTIFY | _TIF_PATCH_PENDING)
 
 static void exit_to_usermode_loop(struct pt_regs *regs, u32 cached_flags)
 {
 	/*
 	 * In order to return to user mode, we need to have IRQs off with
-	 * none of _TIF_SIGPENDING, _TIF_NOTIFY_RESUME, _TIF_USER_RETURN_NOTIFY,
-	 * _TIF_UPROBE, or _TIF_NEED_RESCHED set.  Several of these flags
+	 * none of EXIT_TO_USERMODE_LOOP_FLAGS set.  Several of these flags
 	 * can be set at any time on preemptable kernels if we have IRQs on,
 	 * so we need to loop.  Disabling preemption wouldn't help: doing the
 	 * work to clear some of the flags can sleep.
@@ -236,6 +236,9 @@ static void exit_to_usermode_loop(struct pt_regs *regs, u32 cached_flags)
 		if (cached_flags & _TIF_USER_RETURN_NOTIFY)
 			fire_user_return_notifiers();
 
+		if (cached_flags & _TIF_PATCH_PENDING)
+			klp_patch_task(current);
+
 		/* Disable IRQs and retry */
 		local_irq_disable();
 
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index 30c133a..4e4f50e 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -97,6 +97,7 @@ struct thread_info {
 #define TIF_SECCOMP		8	/* secure computing */
 #define TIF_USER_RETURN_NOTIFY	11	/* notify kernel of userspace return */
 #define TIF_UPROBE		12	/* breakpointed or singlestepping */
+#define TIF_PATCH_PENDING	13	/* pending live patching update */
 #define TIF_NOTSC		16	/* TSC is not accessible in userland */
 #define TIF_IA32		17	/* IA32 compatibility process */
 #define TIF_FORK		18	/* ret_from_fork */
@@ -121,6 +122,7 @@ struct thread_info {
 #define _TIF_SECCOMP		(1 << TIF_SECCOMP)
 #define _TIF_USER_RETURN_NOTIFY	(1 << TIF_USER_RETURN_NOTIFY)
 #define _TIF_UPROBE		(1 << TIF_UPROBE)
+#define _TIF_PATCH_PENDING	(1 << TIF_PATCH_PENDING)
 #define _TIF_NOTSC		(1 << TIF_NOTSC)
 #define _TIF_IA32		(1 << TIF_IA32)
 #define _TIF_FORK		(1 << TIF_FORK)
-- 
2.4.11

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Thread

[RFC PATCH v2 00/18] livepatch: hybrid consistency model Josh Poimboeuf <jpoimboe@redhat.com> - 2016-04-28 22:50 +0200
  [RFC PATCH v2 14/18] livepatch: remove unnecessary object loaded check Josh Poimboeuf <jpoimboe@redhat.com> - 2016-04-28 22:50 +0200
  [RFC PATCH v2 10/18] livepatch/powerpc: add TIF_PATCH_PENDING thread flag Josh Poimboeuf <jpoimboe@redhat.com> - 2016-04-28 22:50 +0200
    Re: [RFC PATCH v2 10/18] livepatch/powerpc: add TIF_PATCH_PENDING  thread flag Petr Mladek <pmladek@suse.com> - 2016-05-03 11:10 +0200
      Re: [RFC PATCH v2 10/18] livepatch/powerpc: add TIF_PATCH_PENDING  thread flag Miroslav Benes <mbenes@suse.cz> - 2016-05-03 14:10 +0200
  [RFC PATCH v2 16/18] livepatch: store function sizes Josh Poimboeuf <jpoimboe@redhat.com> - 2016-04-28 22:50 +0200
  [RFC PATCH v2 05/18] sched: add task flag for preempt IRQ tracking Josh Poimboeuf <jpoimboe@redhat.com> - 2016-04-28 22:50 +0200
    Re: [RFC PATCH v2 05/18] sched: add task flag for preempt IRQ tracking Andy Lutomirski <luto@amacapital.net> - 2016-04-29 20:10 +0200
      Re: [RFC PATCH v2 05/18] sched: add task flag for preempt IRQ tracking Andy Lutomirski <luto@amacapital.net> - 2016-04-29 22:20 +0200
        Re: [RFC PATCH v2 05/18] sched: add task flag for preempt IRQ  tracking Josh Poimboeuf <jpoimboe@redhat.com> - 2016-04-29 22:30 +0200
          Re: [RFC PATCH v2 05/18] sched: add task flag for preempt IRQ tracking Andy Lutomirski <luto@amacapital.net> - 2016-04-29 22:40 +0200
            Re: [RFC PATCH v2 05/18] sched: add task flag for preempt IRQ  tracking Josh Poimboeuf <jpoimboe@redhat.com> - 2016-04-29 23:30 +0200
              Re: [RFC PATCH v2 05/18] sched: add task flag for preempt IRQ tracking Andy Lutomirski <luto@amacapital.net> - 2016-04-29 23:40 +0200
                Re: [RFC PATCH v2 05/18] sched: add task flag for preempt IRQ  tracking Jiri Kosina <jikos@kernel.org> - 2016-04-30 00:20 +0200
                Re: [RFC PATCH v2 05/18] sched: add task flag for preempt IRQ  tracking Josh Poimboeuf <jpoimboe@redhat.com> - 2016-04-30 01:00 +0200
                Re: [RFC PATCH v2 05/18] sched: add task flag for preempt IRQ tracking Andy Lutomirski <luto@amacapital.net> - 2016-04-30 02:20 +0200
                Re: [RFC PATCH v2 05/18] sched: add task flag for preempt IRQ  tracking Josh Poimboeuf <jpoimboe@redhat.com> - 2016-04-30 00:50 +0200
                Re: [RFC PATCH v2 05/18] sched: add task flag for preempt IRQ tracking Andy Lutomirski <luto@amacapital.net> - 2016-04-30 02:10 +0200
                Re: [RFC PATCH v2 05/18] sched: add task flag for preempt IRQ  tracking Josh Poimboeuf <jpoimboe@redhat.com> - 2016-05-02 16:00 +0200
                Re: [RFC PATCH v2 05/18] sched: add task flag for preempt IRQ tracking Andy Lutomirski <luto@amacapital.net> - 2016-05-02 18:00 +0200
                Re: [RFC PATCH v2 05/18] sched: add task flag for preempt IRQ  tracking Josh Poimboeuf <jpoimboe@redhat.com> - 2016-05-02 19:40 +0200
                Re: [RFC PATCH v2 05/18] sched: add task flag for preempt IRQ tracking Andy Lutomirski <luto@amacapital.net> - 2016-05-02 20:20 +0200
                Re: [RFC PATCH v2 05/18] sched: add task flag for preempt IRQ  tracking Ingo Molnar <mingo@kernel.org> - 2016-05-02 20:40 +0200
                Re: [RFC PATCH v2 05/18] sched: add task flag for preempt IRQ  tracking Josh Poimboeuf <jpoimboe@redhat.com> - 2016-05-02 21:50 +0200
                Re: [RFC PATCH v2 05/18] sched: add task flag for preempt IRQ  tracking Jiri Kosina <jikos@kernel.org> - 2016-05-02 22:00 +0200
                Re: [RFC PATCH v2 05/18] sched: add task flag for preempt IRQ  tracking Jiri Kosina <jikos@kernel.org> - 2016-05-02 22:10 +0200
                Re: [RFC PATCH v2 05/18] sched: add task flag for preempt IRQ tracking Andy Lutomirski <luto@amacapital.net> - 2016-05-03 02:50 +0200
                RE: [RFC PATCH v2 05/18] sched: add task flag for preempt IRQ  tracking David Laight <David.Laight@ACULAB.COM> - 2016-05-04 17:20 +0200
      Re: [RFC PATCH v2 05/18] sched: add task flag for preempt IRQ  tracking Josh Poimboeuf <jpoimboe@redhat.com> - 2016-04-29 22:20 +0200
  [RFC PATCH v2 09/18] livepatch/x86: add TIF_PATCH_PENDING thread flag Josh Poimboeuf <jpoimboe@redhat.com> - 2016-04-28 22:50 +0200
    Re: [RFC PATCH v2 09/18] livepatch/x86: add TIF_PATCH_PENDING thread flag Andy Lutomirski <luto@amacapital.net> - 2016-04-29 20:10 +0200
      Re: [RFC PATCH v2 09/18] livepatch/x86: add TIF_PATCH_PENDING thread  flag Josh Poimboeuf <jpoimboe@redhat.com> - 2016-04-29 22:20 +0200
  [RFC PATCH v2 02/18] x86/asm/head: use a common function for starting CPUs Josh Poimboeuf <jpoimboe@redhat.com> - 2016-04-28 22:50 +0200
  [RFC PATCH v2 13/18] livepatch: separate enabled and patched states Josh Poimboeuf <jpoimboe@redhat.com> - 2016-04-28 22:50 +0200
    Re: [RFC PATCH v2 13/18] livepatch: separate enabled and patched  states Petr Mladek <pmladek@suse.com> - 2016-05-03 11:40 +0200
      Re: [RFC PATCH v2 13/18] livepatch: separate enabled and patched  states Josh Poimboeuf <jpoimboe@redhat.com> - 2016-05-03 15:50 +0200
  [RFC PATCH v2 06/18] x86: dump_trace() error handling Josh Poimboeuf <jpoimboe@redhat.com> - 2016-04-28 22:50 +0200
    Re: [RFC PATCH v2 06/18] x86: dump_trace() error handling Minfei Huang <mnghuan@gmail.com> - 2016-04-29 15:50 +0200
      Re: [RFC PATCH v2 06/18] x86: dump_trace() error handling Josh Poimboeuf <jpoimboe@redhat.com> - 2016-04-29 16:10 +0200
  [RFC PATCH v2 03/18] x86/asm/head: standardize the bottom of the stack for idle tasks Josh Poimboeuf <jpoimboe@redhat.com> - 2016-04-28 23:00 +0200
    Re: [RFC PATCH v2 03/18] x86/asm/head: standardize the bottom of the  stack for idle tasks Brian Gerst <brgerst@gmail.com> - 2016-04-29 20:50 +0200
      Re: [RFC PATCH v2 03/18] x86/asm/head: standardize the bottom of the  stack for idle tasks Josh Poimboeuf <jpoimboe@redhat.com> - 2016-04-29 22:30 +0200
    Re: [RFC PATCH v2 03/18] x86/asm/head: standardize the bottom of the  stack for idle tasks Andy Lutomirski <luto@kernel.org> - 2016-04-29 21:40 +0200
      Re: [RFC PATCH v2 03/18] x86/asm/head: standardize the bottom of the  stack for idle tasks Josh Poimboeuf <jpoimboe@redhat.com> - 2016-04-29 23:00 +0200
        Re: [RFC PATCH v2 03/18] x86/asm/head: standardize the bottom of the  stack for idle tasks Andy Lutomirski <luto@amacapital.net> - 2016-04-29 23:40 +0200
          Re: [RFC PATCH v2 03/18] x86/asm/head: standardize the bottom of the  stack for idle tasks Josh Poimboeuf <jpoimboe@redhat.com> - 2016-04-30 01:30 +0200
            Re: [RFC PATCH v2 03/18] x86/asm/head: standardize the bottom of the  stack for idle tasks Andy Lutomirski <luto@amacapital.net> - 2016-04-30 02:20 +0200
  [RFC PATCH v2 04/18] x86: move _stext marker before head code Josh Poimboeuf <jpoimboe@redhat.com> - 2016-04-28 23:00 +0200
  [RFC PATCH v2 01/18] x86/asm/head: clean up initial stack variable Josh Poimboeuf <jpoimboe@redhat.com> - 2016-04-28 23:00 +0200
  Re: [RFC PATCH v2 17/18] livepatch: change to a per-task consistency  model Petr Mladek <pmladek@suse.com> - 2016-05-04 10:50 +0200
    Re: [RFC PATCH v2 17/18] livepatch: change to a per-task consistency  model Josh Poimboeuf <jpoimboe@redhat.com> - 2016-05-04 18:00 +0200
      Re: [RFC PATCH v2 17/18] livepatch: change to a per-task consistency  model Miroslav Benes <mbenes@suse.cz> - 2016-05-05 11:50 +0200
      Re: [RFC PATCH v2 17/18] livepatch: change to a per-task consistency  model Petr Mladek <pmladek@suse.com> - 2016-05-05 15:10 +0200
  barriers: was: [RFC PATCH v2 17/18] livepatch: change to a per-task  consistency model Petr Mladek <pmladek@suse.com> - 2016-05-04 14:40 +0200
    Re: barriers: was: [RFC PATCH v2 17/18] livepatch: change to a  per-task consistency model Peter Zijlstra <peterz@infradead.org> - 2016-05-04 16:00 +0200
      Re: barriers: was: [RFC PATCH v2 17/18] livepatch: change to a  per-task consistency model Josh Poimboeuf <jpoimboe@redhat.com> - 2016-05-04 19:00 +0200
    Re: barriers: was: [RFC PATCH v2 17/18] livepatch: change to a  per-task consistency model Petr Mladek <pmladek@suse.com> - 2016-05-04 16:20 +0200
      Re: barriers: was: [RFC PATCH v2 17/18] livepatch: change to a  per-task consistency model Josh Poimboeuf <jpoimboe@redhat.com> - 2016-05-04 19:30 +0200
        Re: barriers: was: [RFC PATCH v2 17/18] livepatch: change to a  per-task consistency model Petr Mladek <pmladek@suse.com> - 2016-05-05 13:30 +0200
        Re: barriers: was: [RFC PATCH v2 17/18] livepatch: change to a  per-task consistency model Miroslav Benes <mbenes@suse.cz> - 2016-05-09 17:50 +0200
    Re: barriers: was: [RFC PATCH v2 17/18] livepatch: change to a  per-task consistency model Josh Poimboeuf <jpoimboe@redhat.com> - 2016-05-04 19:10 +0200
      Re: barriers: was: [RFC PATCH v2 17/18] livepatch: change to a  per-task consistency model Petr Mladek <pmladek@suse.com> - 2016-05-05 12:30 +0200
  klp_task_patch: was: [RFC PATCH v2 17/18] livepatch: change to a  per-task consistency model Petr Mladek <pmladek@suse.com> - 2016-05-04 16:50 +0200
    Re: klp_task_patch: was: [RFC PATCH v2 17/18] livepatch: change to  a per-task consistency model Jiri Kosina <jikos@kernel.org> - 2016-05-04 17:00 +0200
    Re: klp_task_patch: was: [RFC PATCH v2 17/18] livepatch: change to a  per-task consistency model Josh Poimboeuf <jpoimboe@redhat.com> - 2016-05-04 20:00 +0200
      Re: klp_task_patch: was: [RFC PATCH v2 17/18] livepatch: change to a  per-task consistency model Petr Mladek <pmladek@suse.com> - 2016-05-05 14:00 +0200
        Re: klp_task_patch: was: [RFC PATCH v2 17/18] livepatch: change to a  per-task consistency model Josh Poimboeuf <jpoimboe@redhat.com> - 2016-05-06 14:40 +0200
          Re: klp_task_patch: was: [RFC PATCH v2 17/18] livepatch: change to a  per-task consistency model Petr Mladek <pmladek@suse.com> - 2016-05-09 14:30 +0200
  Re: [RFC PATCH v2 17/18] livepatch: change to a per-task consistency  model Petr Mladek <pmladek@suse.com> - 2016-05-06 13:40 +0200
    Re: [RFC PATCH v2 17/18] livepatch: change to a per-task consistency  model Josh Poimboeuf <jpoimboe@redhat.com> - 2016-05-06 14:50 +0200
  Re: [RFC PATCH v2 17/18] livepatch: change to a per-task consistency  model Miroslav Benes <mbenes@suse.cz> - 2016-05-09 11:50 +0200
  Re: [RFC PATCH v2 17/18] livepatch: change to a per-task consistency  model Miroslav Benes <mbenes@suse.cz> - 2016-05-10 13:50 +0200

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