x86: unify chunks of kernel/process*.c

With x86-32 and -64 using the same mechanism for managing the
tss io permissions bitmap, large chunks of process*.c are
trivially unifyable, including:

 - exit_thread
 - flush_thread
 - __switch_to_xtra (along with tsc enable/disable)

and as bonus pickups:

 - sys_fork
 - sys_vfork

(Note: asmlinkage expands to empty on x86-64)

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

4 files changed, 192 insertions, 361 deletions

diff --git a/arch/x86/include/asm/system.h b/arch/x86/include/asm/system.h
index c00bfdbdd456..1a7bf39f72dc 100644
--- a/arch/x86/include/asm/system.h
+++ b/arch/x86/include/asm/system.h
@@ -20,6 +20,8 @@
 struct task_struct; /* one of the stranger aspects of C forward declarations */
 struct task_struct *__switch_to(struct task_struct *prev,
                                 struct task_struct *next);
+void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p,
+                      struct tss_struct *tss);
 
 #ifdef CONFIG_X86_32
 
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 87b69d4fac16..6afa5232dbb7 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -1,8 +1,8 @@
 #include <linux/errno.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
-#include <asm/idle.h>
 #include <linux/smp.h>
+#include <linux/prctl.h>
 #include <linux/slab.h>
 #include <linux/sched.h>
 #include <linux/module.h>
@@ -11,6 +11,9 @@
 #include <linux/ftrace.h>
 #include <asm/system.h>
 #include <asm/apic.h>
+#include <asm/idle.h>
+#include <asm/uaccess.h>
+#include <asm/i387.h>
 
 unsigned long idle_halt;
 EXPORT_SYMBOL(idle_halt);
@@ -56,6 +59,192 @@ void arch_task_cache_init(void)
 }
 
 /*
+ * Free current thread data structures etc..
+ */
+void exit_thread(void)
+{
+        struct task_struct *me = current;
+        struct thread_struct *t = &me->thread;
+
+        if (me->thread.io_bitmap_ptr) {
+                struct tss_struct *tss = &per_cpu(init_tss, get_cpu());
+
+                kfree(t->io_bitmap_ptr);
+                t->io_bitmap_ptr = NULL;
+                clear_thread_flag(TIF_IO_BITMAP);
+                /*
+                 * Careful, clear this in the TSS too:
+                 */
+                memset(tss->io_bitmap, 0xff, t->io_bitmap_max);
+                t->io_bitmap_max = 0;
+                put_cpu();
+        }
+
+        ds_exit_thread(current);
+}
+
+void flush_thread(void)
+{
+        struct task_struct *tsk = current;
+
+#ifdef CONFIG_X86_64
+        if (test_tsk_thread_flag(tsk, TIF_ABI_PENDING)) {
+                clear_tsk_thread_flag(tsk, TIF_ABI_PENDING);
+                if (test_tsk_thread_flag(tsk, TIF_IA32)) {
+                        clear_tsk_thread_flag(tsk, TIF_IA32);
+                } else {
+                        set_tsk_thread_flag(tsk, TIF_IA32);
+                        current_thread_info()->status |= TS_COMPAT;
+                }
+        }
+#endif
+
+        clear_tsk_thread_flag(tsk, TIF_DEBUG);
+
+        tsk->thread.debugreg0 = 0;
+        tsk->thread.debugreg1 = 0;
+        tsk->thread.debugreg2 = 0;
+        tsk->thread.debugreg3 = 0;
+        tsk->thread.debugreg6 = 0;
+        tsk->thread.debugreg7 = 0;
+        memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array));
+        /*
+         * Forget coprocessor state..
+         */
+        tsk->fpu_counter = 0;
+        clear_fpu(tsk);
+        clear_used_math();
+}
+
+static void hard_disable_TSC(void)
+{
+        write_cr4(read_cr4() | X86_CR4_TSD);
+}
+
+void disable_TSC(void)
+{
+        preempt_disable();
+        if (!test_and_set_thread_flag(TIF_NOTSC))
+                /*
+                 * Must flip the CPU state synchronously with
+                 * TIF_NOTSC in the current running context.
+                 */
+                hard_disable_TSC();
+        preempt_enable();
+}
+
+static void hard_enable_TSC(void)
+{
+        write_cr4(read_cr4() & ~X86_CR4_TSD);
+}
+
+static void enable_TSC(void)
+{
+        preempt_disable();
+        if (test_and_clear_thread_flag(TIF_NOTSC))
+                /*
+                 * Must flip the CPU state synchronously with
+                 * TIF_NOTSC in the current running context.
+                 */
+                hard_enable_TSC();
+        preempt_enable();
+}
+
+int get_tsc_mode(unsigned long adr)
+{
+        unsigned int val;
+
+        if (test_thread_flag(TIF_NOTSC))
+                val = PR_TSC_SIGSEGV;
+        else
+                val = PR_TSC_ENABLE;
+
+        return put_user(val, (unsigned int __user *)adr);
+}
+
+int set_tsc_mode(unsigned int val)
+{
+        if (val == PR_TSC_SIGSEGV)
+                disable_TSC();
+        else if (val == PR_TSC_ENABLE)
+                enable_TSC();
+        else
+                return -EINVAL;
+
+        return 0;
+}
+
+void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p,
+                      struct tss_struct *tss)
+{
+        struct thread_struct *prev, *next;
+
+        prev = &prev_p->thread;
+        next = &next_p->thread;
+
+        if (test_tsk_thread_flag(next_p, TIF_DS_AREA_MSR) ||
+            test_tsk_thread_flag(prev_p, TIF_DS_AREA_MSR))
+                ds_switch_to(prev_p, next_p);
+        else if (next->debugctlmsr != prev->debugctlmsr)
+                update_debugctlmsr(next->debugctlmsr);
+
+        if (test_tsk_thread_flag(next_p, TIF_DEBUG)) {
+                set_debugreg(next->debugreg0, 0);
+                set_debugreg(next->debugreg1, 1);
+                set_debugreg(next->debugreg2, 2);
+                set_debugreg(next->debugreg3, 3);
+                /* no 4 and 5 */
+                set_debugreg(next->debugreg6, 6);
+                set_debugreg(next->debugreg7, 7);
+        }
+
+        if (test_tsk_thread_flag(prev_p, TIF_NOTSC) ^
+            test_tsk_thread_flag(next_p, TIF_NOTSC)) {
+                /* prev and next are different */
+                if (test_tsk_thread_flag(next_p, TIF_NOTSC))
+                        hard_disable_TSC();
+                else
+                        hard_enable_TSC();
+        }
+
+        if (test_tsk_thread_flag(next_p, TIF_IO_BITMAP)) {
+                /*
+                 * Copy the relevant range of the IO bitmap.
+                 * Normally this is 128 bytes or less:
+                 */
+                memcpy(tss->io_bitmap, next->io_bitmap_ptr,
+                       max(prev->io_bitmap_max, next->io_bitmap_max));
+        } else if (test_tsk_thread_flag(prev_p, TIF_IO_BITMAP)) {
+                /*
+                 * Clear any possible leftover bits:
+                 */
+                memset(tss->io_bitmap, 0xff, prev->io_bitmap_max);
+        }
+}
+
+int sys_fork(struct pt_regs *regs)
+{
+        return do_fork(SIGCHLD, regs->sp, regs, 0, NULL, NULL);
+}
+
+/*
+ * This is trivial, and on the face of it looks like it
+ * could equally well be done in user mode.
+ *
+ * Not so, for quite unobvious reasons - register pressure.
+ * In user mode vfork() cannot have a stack frame, and if
+ * done by calling the "clone()" system call directly, you
+ * do not have enough call-clobbered registers to hold all
+ * the information you need.
+ */
+int sys_vfork(struct pt_regs *regs)
+{
+        return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->sp, regs, 0,
+                       NULL, NULL);
+}
+
+
+/*
  * Idle related variables and functions
  */
 unsigned long boot_option_idle_override = 0;
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index a59314e877f0..14014d766cad 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -230,52 +230,6 @@ int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
 }
 EXPORT_SYMBOL(kernel_thread);
 
-/*
- * Free current thread data structures etc..
- */
-void exit_thread(void)
-{
-        /* The process may have allocated an io port bitmap... nuke it. */
-        if (unlikely(test_thread_flag(TIF_IO_BITMAP))) {
-                struct task_struct *tsk = current;
-                struct thread_struct *t = &tsk->thread;
-                int cpu = get_cpu();
-                struct tss_struct *tss = &per_cpu(init_tss, cpu);
-
-                kfree(t->io_bitmap_ptr);
-                t->io_bitmap_ptr = NULL;
-                clear_thread_flag(TIF_IO_BITMAP);
-                /*
-                 * Careful, clear this in the TSS too:
-                 */
-                memset(tss->io_bitmap, 0xff, t->io_bitmap_max);
-                t->io_bitmap_max = 0;
-                put_cpu();
-        }
-
-        ds_exit_thread(current);
-}
-
-void flush_thread(void)
-{
-        struct task_struct *tsk = current;
-
-        tsk->thread.debugreg0 = 0;
-        tsk->thread.debugreg1 = 0;
-        tsk->thread.debugreg2 = 0;
-        tsk->thread.debugreg3 = 0;
-        tsk->thread.debugreg6 = 0;
-        tsk->thread.debugreg7 = 0;
-        memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array));
-        clear_tsk_thread_flag(tsk, TIF_DEBUG);
-        /*
-         * Forget coprocessor state..
-         */
-        tsk->fpu_counter = 0;
-        clear_fpu(tsk);
-        clear_used_math();
-}
-
 void release_thread(struct task_struct *dead_task)
 {
         BUG_ON(dead_task->mm);
@@ -363,112 +317,6 @@ start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
 }
 EXPORT_SYMBOL_GPL(start_thread);
 
-static void hard_disable_TSC(void)
-{
-        write_cr4(read_cr4() | X86_CR4_TSD);
-}
-
-void disable_TSC(void)
-{
-        preempt_disable();
-        if (!test_and_set_thread_flag(TIF_NOTSC))
-                /*
-                 * Must flip the CPU state synchronously with
-                 * TIF_NOTSC in the current running context.
-                 */
-                hard_disable_TSC();
-        preempt_enable();
-}
-
-static void hard_enable_TSC(void)
-{
-        write_cr4(read_cr4() & ~X86_CR4_TSD);
-}
-
-static void enable_TSC(void)
-{
-        preempt_disable();
-        if (test_and_clear_thread_flag(TIF_NOTSC))
-                /*
-                 * Must flip the CPU state synchronously with
-                 * TIF_NOTSC in the current running context.
-                 */
-                hard_enable_TSC();
-        preempt_enable();
-}
-
-int get_tsc_mode(unsigned long adr)
-{
-        unsigned int val;
-
-        if (test_thread_flag(TIF_NOTSC))
-                val = PR_TSC_SIGSEGV;
-        else
-                val = PR_TSC_ENABLE;
-
-        return put_user(val, (unsigned int __user *)adr);
-}
-
-int set_tsc_mode(unsigned int val)
-{
-        if (val == PR_TSC_SIGSEGV)
-                disable_TSC();
-        else if (val == PR_TSC_ENABLE)
-                enable_TSC();
-        else
-                return -EINVAL;
-
-        return 0;
-}
-
-static noinline void
-__switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p,
-                 struct tss_struct *tss)
-{
-        struct thread_struct *prev, *next;
-
-        prev = &prev_p->thread;
-        next = &next_p->thread;
-
-        if (test_tsk_thread_flag(next_p, TIF_DS_AREA_MSR) ||
-            test_tsk_thread_flag(prev_p, TIF_DS_AREA_MSR))
-                ds_switch_to(prev_p, next_p);
-        else if (next->debugctlmsr != prev->debugctlmsr)
-                update_debugctlmsr(next->debugctlmsr);
-
-        if (test_tsk_thread_flag(next_p, TIF_DEBUG)) {
-                set_debugreg(next->debugreg0, 0);
-                set_debugreg(next->debugreg1, 1);
-                set_debugreg(next->debugreg2, 2);
-                set_debugreg(next->debugreg3, 3);
-                /* no 4 and 5 */
-                set_debugreg(next->debugreg6, 6);
-                set_debugreg(next->debugreg7, 7);
-        }
-
-        if (test_tsk_thread_flag(prev_p, TIF_NOTSC) ^
-            test_tsk_thread_flag(next_p, TIF_NOTSC)) {
-                /* prev and next are different */
-                if (test_tsk_thread_flag(next_p, TIF_NOTSC))
-                        hard_disable_TSC();
-                else
-                        hard_enable_TSC();
-        }
-
-        if (test_tsk_thread_flag(next_p, TIF_IO_BITMAP)) {
-                /*
-                 * Copy the relevant range of the IO bitmap.
-                 * Normally this is 128 bytes or less:
-                 */
-                memcpy(tss->io_bitmap, next->io_bitmap_ptr,
-                       max(prev->io_bitmap_max, next->io_bitmap_max));
-        } else if (test_tsk_thread_flag(prev_p, TIF_IO_BITMAP)) {
-                /*
-                 * Clear any possible leftover bits:
-                 */
-                memset(tss->io_bitmap, 0xff, prev->io_bitmap_max);
-        }
-}
 
 /*
  *      switch_to(x,yn) should switch tasks from x to y.
@@ -582,11 +430,6 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
         return prev_p;
 }
 
-int sys_fork(struct pt_regs *regs)
-{
-        return do_fork(SIGCHLD, regs->sp, regs, 0, NULL, NULL);
-}
-
 int sys_clone(struct pt_regs *regs)
 {
         unsigned long clone_flags;
@@ -603,21 +446,6 @@ int sys_clone(struct pt_regs *regs)
 }
 
 /*
- * This is trivial, and on the face of it looks like it
- * could equally well be done in user mode.
- *
- * Not so, for quite unobvious reasons - register pressure.
- * In user mode vfork() cannot have a stack frame, and if
- * done by calling the "clone()" system call directly, you
- * do not have enough call-clobbered registers to hold all
- * the information you need.
- */
-int sys_vfork(struct pt_regs *regs)
-{
-        return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->sp, regs, 0, NULL, NULL);
-}
-
-/*
  * sys_execve() executes a new program.
  */
 int sys_execve(struct pt_regs *regs)
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 836ef6575f01..abb7e6a7f0c6 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -237,61 +237,6 @@ void show_regs(struct pt_regs *regs)
         show_trace(NULL, regs, (void *)(regs + 1), regs->bp);
 }
 
-/*
- * Free current thread data structures etc..
- */
-void exit_thread(void)
-{
-        struct task_struct *me = current;
-        struct thread_struct *t = &me->thread;
-
-        if (me->thread.io_bitmap_ptr) {
-                struct tss_struct *tss = &per_cpu(init_tss, get_cpu());
-
-                kfree(t->io_bitmap_ptr);
-                t->io_bitmap_ptr = NULL;
-                clear_thread_flag(TIF_IO_BITMAP);
-                /*
-                 * Careful, clear this in the TSS too:
-                 */
-                memset(tss->io_bitmap, 0xff, t->io_bitmap_max);
-                t->io_bitmap_max = 0;
-                put_cpu();
-        }
-
-        ds_exit_thread(current);
-}
-
-void flush_thread(void)
-{
-        struct task_struct *tsk = current;
-
-        if (test_tsk_thread_flag(tsk, TIF_ABI_PENDING)) {
-                clear_tsk_thread_flag(tsk, TIF_ABI_PENDING);
-                if (test_tsk_thread_flag(tsk, TIF_IA32)) {
-                        clear_tsk_thread_flag(tsk, TIF_IA32);
-                } else {
-                        set_tsk_thread_flag(tsk, TIF_IA32);
-                        current_thread_info()->status |= TS_COMPAT;
-                }
-        }
-        clear_tsk_thread_flag(tsk, TIF_DEBUG);
-
-        tsk->thread.debugreg0 = 0;
-        tsk->thread.debugreg1 = 0;
-        tsk->thread.debugreg2 = 0;
-        tsk->thread.debugreg3 = 0;
-        tsk->thread.debugreg6 = 0;
-        tsk->thread.debugreg7 = 0;
-        memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array));
-        /*
-         * Forget coprocessor state..
-         */
-        tsk->fpu_counter = 0;
-        clear_fpu(tsk);
-        clear_used_math();
-}
-
 void release_thread(struct task_struct *dead_task)
 {
         if (dead_task->mm) {
@@ -425,118 +370,6 @@ start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
 }
 EXPORT_SYMBOL_GPL(start_thread);
 
-static void hard_disable_TSC(void)
-{
-        write_cr4(read_cr4() | X86_CR4_TSD);
-}
-
-void disable_TSC(void)
-{
-        preempt_disable();
-        if (!test_and_set_thread_flag(TIF_NOTSC))
-                /*
-                 * Must flip the CPU state synchronously with
-                 * TIF_NOTSC in the current running context.
-                 */
-                hard_disable_TSC();
-        preempt_enable();
-}
-
-static void hard_enable_TSC(void)
-{
-        write_cr4(read_cr4() & ~X86_CR4_TSD);
-}
-
-static void enable_TSC(void)
-{
-        preempt_disable();
-        if (test_and_clear_thread_flag(TIF_NOTSC))
-                /*
-                 * Must flip the CPU state synchronously with
-                 * TIF_NOTSC in the current running context.
-                 */
-                hard_enable_TSC();
-        preempt_enable();
-}
-
-int get_tsc_mode(unsigned long adr)
-{
-        unsigned int val;
-
-        if (test_thread_flag(TIF_NOTSC))
-                val = PR_TSC_SIGSEGV;
-        else
-                val = PR_TSC_ENABLE;
-
-        return put_user(val, (unsigned int __user *)adr);
-}
-
-int set_tsc_mode(unsigned int val)
-{
-        if (val == PR_TSC_SIGSEGV)
-                disable_TSC();
-        else if (val == PR_TSC_ENABLE)
-                enable_TSC();
-        else
-                return -EINVAL;
-
-        return 0;
-}
-
-/*
- * This special macro can be used to load a debugging register
- */
-#define loaddebug(thread, r) set_debugreg(thread->debugreg ## r, r)
-
-static inline void __switch_to_xtra(struct task_struct *prev_p,
-                                    struct task_struct *next_p,
-                                    struct tss_struct *tss)
-{
-        struct thread_struct *prev, *next;
-
-        prev = &prev_p->thread,
-        next = &next_p->thread;
-
-        if (test_tsk_thread_flag(next_p, TIF_DS_AREA_MSR) ||
-            test_tsk_thread_flag(prev_p, TIF_DS_AREA_MSR))
-                ds_switch_to(prev_p, next_p);
-        else if (next->debugctlmsr != prev->debugctlmsr)
-                update_debugctlmsr(next->debugctlmsr);
-
-        if (test_tsk_thread_flag(next_p, TIF_DEBUG)) {
-                loaddebug(next, 0);
-                loaddebug(next, 1);
-                loaddebug(next, 2);
-                loaddebug(next, 3);
-                /* no 4 and 5 */
-                loaddebug(next, 6);
-                loaddebug(next, 7);
-        }
-
-        if (test_tsk_thread_flag(prev_p, TIF_NOTSC) ^
-            test_tsk_thread_flag(next_p, TIF_NOTSC)) {
-                /* prev and next are different */
-                if (test_tsk_thread_flag(next_p, TIF_NOTSC))
-                        hard_disable_TSC();
-                else
-                        hard_enable_TSC();
-        }
-
-        if (test_tsk_thread_flag(next_p, TIF_IO_BITMAP)) {
-                /*
-                 * Copy the relevant range of the IO bitmap.
-                 * Normally this is 128 bytes or less:
-                 */
-                memcpy(tss->io_bitmap, next->io_bitmap_ptr,
-                       max(prev->io_bitmap_max, next->io_bitmap_max));
-        } else if (test_tsk_thread_flag(prev_p, TIF_IO_BITMAP)) {
-                /*
-                 * Clear any possible leftover bits:
-                 */
-                memset(tss->io_bitmap, 0xff, prev->io_bitmap_max);
-        }
-}
-
 /*
  *      switch_to(x,y) should switch tasks from x to y.
  *
@@ -694,11 +527,6 @@ void set_personality_64bit(void)
         current->personality &= ~READ_IMPLIES_EXEC;
 }
 
-asmlinkage long sys_fork(struct pt_regs *regs)
-{
-        return do_fork(SIGCHLD, regs->sp, regs, 0, NULL, NULL);
-}
-
 asmlinkage long
 sys_clone(unsigned long clone_flags, unsigned long newsp,
           void __user *parent_tid, void __user *child_tid, struct pt_regs *regs)
@@ -708,22 +536,6 @@ sys_clone(unsigned long clone_flags, unsigned long newsp,
         return do_fork(clone_flags, newsp, regs, 0, parent_tid, child_tid);
 }
 
-/*
- * This is trivial, and on the face of it looks like it
- * could equally well be done in user mode.
- *
- * Not so, for quite unobvious reasons - register pressure.
- * In user mode vfork() cannot have a stack frame, and if
- * done by calling the "clone()" system call directly, you
- * do not have enough call-clobbered registers to hold all
- * the information you need.
- */
-asmlinkage long sys_vfork(struct pt_regs *regs)
-{
-        return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->sp, regs, 0,
-                    NULL, NULL);
-}
-
 unsigned long get_wchan(struct task_struct *p)
 {
         unsigned long stack;