x86/asm: Move the thread_info::status field to thread_struct

Because sched.h and thread_info.h are a tangled mess, I turned
in_compat_syscall() into a macro.  If we had current_thread_struct()
or similar and we could use it from thread_info.h, then this would
be a bit cleaner.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jann Horn <jann@thejh.net>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/ccc8a1b2f41f9c264a41f771bb4a6539a642ad72.1473801993.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

9 files changed, 27 insertions, 42 deletions

diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index 1433f6b4607d..871bbf975d4c 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -209,7 +209,7 @@ __visible inline void prepare_exit_to_usermode(struct pt_regs *regs)
          * special case only applies after poking regs and before the
          * very next return to user mode.
          */
-        ti->status &= ~(TS_COMPAT|TS_I386_REGS_POKED);
+        current->thread.status &= ~(TS_COMPAT|TS_I386_REGS_POKED);
 #endif
 
         user_enter_irqoff();
@@ -307,7 +307,7 @@ static __always_inline void do_syscall_32_irqs_on(struct pt_regs *regs)
         unsigned int nr = (unsigned int)regs->orig_ax;
 
 #ifdef CONFIG_IA32_EMULATION
-        ti->status |= TS_COMPAT;
+        current->thread.status |= TS_COMPAT;
 #endif
 
         if (READ_ONCE(ti->flags) & _TIF_WORK_SYSCALL_ENTRY) {
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index b22fb5a4ff3c..984a7bf17f6a 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -389,6 +389,9 @@ struct thread_struct {
         unsigned short          fsindex;
         unsigned short          gsindex;
 #endif
+
+        u32                     status;         /* thread synchronous flags */
+
 #ifdef CONFIG_X86_64
         unsigned long           fsbase;
         unsigned long           gsbase;
@@ -435,6 +438,15 @@ struct thread_struct {
 };
 
 /*
+ * Thread-synchronous status.
+ *
+ * This is different from the flags in that nobody else
+ * ever touches our thread-synchronous status, so we don't
+ * have to worry about atomic accesses.
+ */
+#define TS_COMPAT               0x0002  /* 32bit syscall active (64BIT)*/
+
+/*
  * Set IOPL bits in EFLAGS from given mask
  */
 static inline void native_set_iopl_mask(unsigned mask)
diff --git a/arch/x86/include/asm/syscall.h b/arch/x86/include/asm/syscall.h
index 4e23dd15c661..e3c95e8e61c5 100644
--- a/arch/x86/include/asm/syscall.h
+++ b/arch/x86/include/asm/syscall.h
@@ -60,7 +60,7 @@ static inline long syscall_get_error(struct task_struct *task,
          * TS_COMPAT is set for 32-bit syscall entries and then
          * remains set until we return to user mode.
          */
-        if (task_thread_info(task)->status & (TS_COMPAT|TS_I386_REGS_POKED))
+        if (task->thread.status & (TS_COMPAT|TS_I386_REGS_POKED))
                 /*
                  * Sign-extend the value so (int)-EFOO becomes (long)-EFOO
                  * and will match correctly in comparisons.
@@ -116,7 +116,7 @@ static inline void syscall_get_arguments(struct task_struct *task,
                                          unsigned long *args)
 {
 # ifdef CONFIG_IA32_EMULATION
-        if (task_thread_info(task)->status & TS_COMPAT)
+        if (task->thread.status & TS_COMPAT)
                 switch (i) {
                 case 0:
                         if (!n--) break;
@@ -177,7 +177,7 @@ static inline void syscall_set_arguments(struct task_struct *task,
                                          const unsigned long *args)
 {
 # ifdef CONFIG_IA32_EMULATION
-        if (task_thread_info(task)->status & TS_COMPAT)
+        if (task->thread.status & TS_COMPAT)
                 switch (i) {
                 case 0:
                         if (!n--) break;
@@ -234,18 +234,8 @@ static inline void syscall_set_arguments(struct task_struct *task,
 
 static inline int syscall_get_arch(void)
 {
-#ifdef CONFIG_IA32_EMULATION
-        /*
-         * TS_COMPAT is set for 32-bit syscall entry and then
-         * remains set until we return to user mode.
-         *
-         * x32 tasks should be considered AUDIT_ARCH_X86_64.
-         */
-        if (task_thread_info(current)->status & TS_COMPAT)
-                return AUDIT_ARCH_I386;
-#endif
-        /* Both x32 and x86_64 are considered "64-bit". */
-        return AUDIT_ARCH_X86_64;
+        /* x32 tasks should be considered AUDIT_ARCH_X86_64. */
+        return in_ia32_syscall() ? AUDIT_ARCH_I386 : AUDIT_ARCH_X86_64;
 }
 #endif  /* CONFIG_X86_32 */
 
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index 494c4b5ada34..c9dcfe7c7e4b 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -55,7 +55,6 @@ struct task_struct;
 struct thread_info {
         struct task_struct      *task;          /* main task structure */
         __u32                   flags;          /* low level flags */
-        __u32                   status;         /* thread synchronous flags */
         __u32                   cpu;            /* current CPU */
 };
 
@@ -253,31 +252,17 @@ static inline int arch_within_stack_frames(const void * const stack,
 
 #endif
 
-/*
- * Thread-synchronous status.
- *
- * This is different from the flags in that nobody else
- * ever touches our thread-synchronous status, so we don't
- * have to worry about atomic accesses.
- */
-#define TS_COMPAT               0x0002  /* 32bit syscall active (64BIT)*/
 #ifdef CONFIG_COMPAT
 #define TS_I386_REGS_POKED      0x0004  /* regs poked by 32-bit ptracer */
 #endif
-
 #ifndef __ASSEMBLY__
 
-static inline bool in_ia32_syscall(void)
-{
 #ifdef CONFIG_X86_32
-        return true;
-#endif
-#ifdef CONFIG_IA32_EMULATION
-        if (current_thread_info()->status & TS_COMPAT)
-                return true;
+#define in_ia32_syscall() true
+#else
+#define in_ia32_syscall() (IS_ENABLED(CONFIG_IA32_EMULATION) && \
+                           current->thread.status & TS_COMPAT)
 #endif
-        return false;
-}
 
 /*
  * Force syscall return via IRET by making it look as if there was
diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c
index db3a0af9b9ec..add5f90b93d4 100644
--- a/arch/x86/kernel/asm-offsets.c
+++ b/arch/x86/kernel/asm-offsets.c
@@ -36,7 +36,6 @@ void common(void) {
 
         BLANK();
         OFFSET(TI_flags, thread_info, flags);
-        OFFSET(TI_status, thread_info, status);
 
         BLANK();
         OFFSET(TASK_addr_limit, task_struct, thread.addr_limit);
diff --git a/arch/x86/kernel/fpu/init.c b/arch/x86/kernel/fpu/init.c
index 93982aebb398..2f2b8c7ccb85 100644
--- a/arch/x86/kernel/fpu/init.c
+++ b/arch/x86/kernel/fpu/init.c
@@ -317,7 +317,6 @@ static void __init fpu__init_system_ctx_switch(void)
         on_boot_cpu = 0;
 
         WARN_ON_FPU(current->thread.fpu.fpstate_active);
-        current_thread_info()->status = 0;
 
         if (boot_cpu_has(X86_FEATURE_XSAVEOPT) && eagerfpu != DISABLE)
                 eagerfpu = ENABLE;
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index b812cd0d7889..de9acaf2d371 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -510,7 +510,7 @@ void set_personality_ia32(bool x32)
                 current->personality &= ~READ_IMPLIES_EXEC;
                 /* in_compat_syscall() uses the presence of the x32
                    syscall bit flag to determine compat status */
-                current_thread_info()->status &= ~TS_COMPAT;
+                current->thread.status &= ~TS_COMPAT;
         } else {
                 set_thread_flag(TIF_IA32);
                 clear_thread_flag(TIF_X32);
@@ -518,7 +518,7 @@ void set_personality_ia32(bool x32)
                         current->mm->context.ia32_compat = TIF_IA32;
                 current->personality |= force_personality32;
                 /* Prepare the first "return" to user space */
-                current_thread_info()->status |= TS_COMPAT;
+                current->thread.status |= TS_COMPAT;
         }
 }
 EXPORT_SYMBOL_GPL(set_personality_ia32);
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 5b88a1b26fc7..ce94c38cf4d6 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -934,7 +934,7 @@ static int putreg32(struct task_struct *child, unsigned regno, u32 value)
                  */
                 regs->orig_ax = value;
                 if (syscall_get_nr(child, regs) >= 0)
-                        task_thread_info(child)->status |= TS_I386_REGS_POKED;
+                        child->thread.status |= TS_I386_REGS_POKED;
                 break;
 
         case offsetof(struct user32, regs.eflags):
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index 04cb3212db2d..da20ecb5397a 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -783,7 +783,7 @@ static inline unsigned long get_nr_restart_syscall(const struct pt_regs *regs)
          * than the tracee.
          */
 #ifdef CONFIG_IA32_EMULATION
-        if (current_thread_info()->status & (TS_COMPAT|TS_I386_REGS_POKED))
+        if (current->thread.status & (TS_COMPAT|TS_I386_REGS_POKED))
                 return __NR_ia32_restart_syscall;
 #endif
 #ifdef CONFIG_X86_X32_ABI