Merge tag 'pr-20150114-x86-entry' of git://git.kernel.org/pub/scm/linux/kernel/git/luto/linux into x86/asm

Pull x86/entry enhancements from Andy Lutomirski:

" This is my accumulated x86 entry work, part 1, for 3.20.  The meat
  of this is an IST rework.  When an IST exception interrupts user
  space, we will handle it on the per-thread kernel stack instead of
  on the IST stack.  This sounds messy, but it actually simplifies the
  IST entry/exit code, because it eliminates some ugly games we used
  to play in order to handle rescheduling, signal delivery, etc on the
  way out of an IST exception.

  The IST rework introduces proper context tracking to IST exception
  handlers.  I haven't seen any bug reports, but the old code could
  have incorrectly treated an IST exception handler as an RCU extended
  quiescent state.

  The memory failure change (included in this pull request with
  Borislav and Tony's permission) eliminates a bunch of code that
  is no longer needed now that user memory failure handlers are
  called in process context.

  Finally, this includes a few on Denys' uncontroversial and Obviously
  Correct (tm) cleanups.

  The IST and memory failure changes have been in -next for a while.

  LKML references:

  IST rework:
  http://lkml.kernel.org/r/cover.1416604491.git.luto@amacapital.net

  Memory failure change:
  http://lkml.kernel.org/r/54ab2ffa301102cd6e@agluck-desk.sc.intel.com

  Denys' cleanups:
  http://lkml.kernel.org/r/1420927210-19738-1-git-send-email-dvlasenk@redhat.com
"

This tree semantically depends on and is based on the following RCU commit:

  734d16801349 ("rcu: Make rcu_nmi_enter() handle nesting")

... and for that reason won't be pushed upstream before the RCU bits hit Linus's tree.

Signed-off-by: Ingo Molnar <mingo@kernel.org>

4 files changed, 18 insertions, 5 deletions

diff --git a/arch/x86/include/asm/calling.h b/arch/x86/include/asm/calling.h
index 76659b67fd11..1f1297b46f83 100644
--- a/arch/x86/include/asm/calling.h
+++ b/arch/x86/include/asm/calling.h
@@ -83,7 +83,6 @@ For 32-bit we have the following conventions - kernel is built with
 #define SS              160
 
 #define ARGOFFSET       R11
-#define SWFRAME         ORIG_RAX
 
         .macro SAVE_ARGS addskip=0, save_rcx=1, save_r891011=1, rax_enosys=0
         subq  $9*8+\addskip, %rsp
diff --git a/arch/x86/include/asm/mce.h b/arch/x86/include/asm/mce.h
index 51b26e895933..9b3de99dc004 100644
--- a/arch/x86/include/asm/mce.h
+++ b/arch/x86/include/asm/mce.h
@@ -190,7 +190,6 @@ enum mcp_flags {
 void machine_check_poll(enum mcp_flags flags, mce_banks_t *b);
 
 int mce_notify_irq(void);
-void mce_notify_process(void);
 
 DECLARE_PER_CPU(struct mce, injectm);
 
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index 547e344a6dc6..e82e95abc92b 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -75,7 +75,6 @@ struct thread_info {
 #define TIF_SYSCALL_EMU         6       /* syscall emulation active */
 #define TIF_SYSCALL_AUDIT       7       /* syscall auditing active */
 #define TIF_SECCOMP             8       /* secure computing */
-#define TIF_MCE_NOTIFY          10      /* notify userspace of an MCE */
 #define TIF_USER_RETURN_NOTIFY  11      /* notify kernel of userspace return */
 #define TIF_UPROBE              12      /* breakpointed or singlestepping */
 #define TIF_NOTSC               16      /* TSC is not accessible in userland */
@@ -100,7 +99,6 @@ struct thread_info {
 #define _TIF_SYSCALL_EMU        (1 << TIF_SYSCALL_EMU)
 #define _TIF_SYSCALL_AUDIT      (1 << TIF_SYSCALL_AUDIT)
 #define _TIF_SECCOMP            (1 << TIF_SECCOMP)
-#define _TIF_MCE_NOTIFY         (1 << TIF_MCE_NOTIFY)
 #define _TIF_USER_RETURN_NOTIFY (1 << TIF_USER_RETURN_NOTIFY)
 #define _TIF_UPROBE             (1 << TIF_UPROBE)
 #define _TIF_NOTSC              (1 << TIF_NOTSC)
@@ -140,7 +138,7 @@ struct thread_info {
 
 /* Only used for 64 bit */
 #define _TIF_DO_NOTIFY_MASK                                             \
-        (_TIF_SIGPENDING | _TIF_MCE_NOTIFY | _TIF_NOTIFY_RESUME |       \
+        (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME |                         \
          _TIF_USER_RETURN_NOTIFY | _TIF_UPROBE)
 
 /* flags to check in __switch_to() */
@@ -170,6 +168,17 @@ static inline struct thread_info *current_thread_info(void)
         return ti;
 }
 
+static inline unsigned long current_stack_pointer(void)
+{
+        unsigned long sp;
+#ifdef CONFIG_X86_64
+        asm("mov %%rsp,%0" : "=g" (sp));
+#else
+        asm("mov %%esp,%0" : "=g" (sp));
+#endif
+        return sp;
+}
+
 #else /* !__ASSEMBLY__ */
 
 /* how to get the thread information struct from ASM */
diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h
index 707adc6549d8..4e49d7dff78e 100644
--- a/arch/x86/include/asm/traps.h
+++ b/arch/x86/include/asm/traps.h
@@ -1,6 +1,7 @@
 #ifndef _ASM_X86_TRAPS_H
 #define _ASM_X86_TRAPS_H
 
+#include <linux/context_tracking_state.h>
 #include <linux/kprobes.h>
 
 #include <asm/debugreg.h>
@@ -110,6 +111,11 @@ asmlinkage void smp_thermal_interrupt(void);
 asmlinkage void mce_threshold_interrupt(void);
 #endif
 
+extern enum ctx_state ist_enter(struct pt_regs *regs);
+extern void ist_exit(struct pt_regs *regs, enum ctx_state prev_state);
+extern void ist_begin_non_atomic(struct pt_regs *regs);
+extern void ist_end_non_atomic(void);
+
 /* Interrupts/Exceptions */
 enum {
         X86_TRAP_DE = 0,        /*  0, Divide-by-zero */