MN10300: Save frame pointer in thread_info struct rather than global var

Save the current exception frame pointer in the thread_info struct rather than
in a global variable as the latter makes SMP tricky, especially when preemption
is also enabled.

This also replaces __frame with current_frame() and rearranges header file
inclusions to make it all compile.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Akira Takeuchi <takeuchi.akr@jp.panasonic.com>

8 files changed, 51 insertions, 99 deletions

diff --git a/arch/mn10300/include/asm/frame.inc b/arch/mn10300/include/asm/frame.inc
index 406060e5e1c0..2ee58e3eb6b3 100644
--- a/arch/mn10300/include/asm/frame.inc
+++ b/arch/mn10300/include/asm/frame.inc
@@ -18,9 +18,7 @@
 #ifndef __ASM_OFFSETS_H__
 #include <asm/asm-offsets.h>
 #endif
-#ifdef CONFIG_SMP
-#include <proc/smp-regs.h>
-#endif
+#include <asm/thread_info.h>
 
 #define pi break
 
@@ -40,27 +38,15 @@
         movm    [d2,d3,a2,a3,exreg0,exreg1,exother],(sp)
         mov     sp,fp                           # FRAME pointer in A3
         add     -12,sp                          # allow for calls to be made
-#ifdef CONFIG_SMP
-#ifdef CONFIG_PREEMPT /* FIXME */
-        mov     epsw,d2
-        and     ~EPSW_IE,epsw
-#endif
-        mov     (CPUID),a0
-        add     a0,a0
-        add     a0,a0
-        mov     (___frame,a0),a1
-        mov     a1,(REG_NEXT,fp)
-        mov     fp,(___frame,a0)
-#ifdef CONFIG_PREEMPT /* FIXME */
-        mov     d2,epsw
-#endif
-#else  /* CONFIG_SMP */
-        mov     (__frame),a1
-        mov     a1,(REG_NEXT,fp)
-        mov     fp,(__frame)
-#endif /* CONFIG_SMP */
 
-        and     ~EPSW_FE,epsw                   # disable the FPU inside the kernel
+        # push the exception frame onto the front of the list
+        GET_THREAD_INFO a1
+        mov     (TI_frame,a1),a0
+        mov     a0,(REG_NEXT,fp)
+        mov     fp,(TI_frame,a1)
+
+        # disable the FPU inside the kernel
+        and     ~EPSW_FE,epsw
 
         # we may be holding current in E2
 #ifdef CONFIG_MN10300_CURRENT_IN_E2
@@ -76,27 +62,11 @@
 .macro RESTORE_ALL
         # peel back the stack to the calling frame
         # - this permits execve() to discard extra frames due to kernel syscalls
-#ifdef  CONFIG_SMP
-#ifdef CONFIG_PREEMPT /* FIXME */
-        mov     epsw,d2
-        and     ~EPSW_IE,epsw
-#endif
-        mov     (CPUID),a0
-        add     a0,a0
-        add     a0,a0
-        mov     (___frame,a0),fp
-        mov     fp,sp
-        mov     (REG_NEXT,fp),d0                # userspace has regs->next == 0
-        mov     d0,(___frame,a0)
-#ifdef CONFIG_PREEMPT /* FIXME */
-        mov     d2,epsw
-#endif
-#else   /* CONFIG_SMP */
-        mov     (__frame),fp
+        GET_THREAD_INFO a0
+        mov     (TI_frame,a0),fp
         mov     fp,sp
-        mov     (REG_NEXT,fp),d0                # userspace has regs->next == 0
-        mov     d0,(__frame)
-#endif  /* CONFIG_SMP */
+        mov     (REG_NEXT,fp),d0
+        mov     d0,(TI_frame,a0)                # userspace has regs->next == 0
 
 #ifndef CONFIG_MN10300_USING_JTAG
         mov     (REG_EPSW,fp),d0
diff --git a/arch/mn10300/include/asm/irq_regs.h b/arch/mn10300/include/asm/irq_regs.h
index a848cd232eb4..97d0cb5af807 100644
--- a/arch/mn10300/include/asm/irq_regs.h
+++ b/arch/mn10300/include/asm/irq_regs.h
@@ -18,7 +18,11 @@
 #define ARCH_HAS_OWN_IRQ_REGS
 
 #ifndef __ASSEMBLY__
-#define get_irq_regs() (__frame)
+static inline __attribute__((const))
+struct pt_regs *get_irq_regs(void)
+{
+        return current_frame();
+}
 #endif
 
 #endif /* _ASM_IRQ_REGS_H */
diff --git a/arch/mn10300/include/asm/pgalloc.h b/arch/mn10300/include/asm/pgalloc.h
index a19f11327cd8..146bacf193ea 100644
--- a/arch/mn10300/include/asm/pgalloc.h
+++ b/arch/mn10300/include/asm/pgalloc.h
@@ -11,7 +11,6 @@
 #ifndef _ASM_PGALLOC_H
 #define _ASM_PGALLOC_H
 
-#include <asm/processor.h>
 #include <asm/page.h>
 #include <linux/threads.h>
 #include <linux/mm.h>           /* for struct page */
diff --git a/arch/mn10300/include/asm/processor.h b/arch/mn10300/include/asm/processor.h
index 75c422abcd6b..4c1b5cc14c19 100644
--- a/arch/mn10300/include/asm/processor.h
+++ b/arch/mn10300/include/asm/processor.h
@@ -13,10 +13,13 @@
 #ifndef _ASM_PROCESSOR_H
 #define _ASM_PROCESSOR_H
 
+#include <linux/threads.h>
+#include <linux/thread_info.h>
 #include <asm/page.h>
 #include <asm/ptrace.h>
 #include <asm/cpu-regs.h>
-#include <linux/threads.h>
+#include <asm/uaccess.h>
+#include <asm/current.h>
 
 /* Forward declaration, a strange C thing */
 struct task_struct;
@@ -83,10 +86,6 @@ extern void dodgy_tsc(void);
  */
 #define TASK_UNMAPPED_BASE      0x30000000
 
-typedef struct {
-        unsigned long   seg;
-} mm_segment_t;
-
 struct fpu_state_struct {
         unsigned long   fs[32];         /* fpu registers */
         unsigned long   fpcr;           /* fpu control register */
@@ -99,7 +98,6 @@ struct thread_struct {
         unsigned long           a3;             /* kernel FP */
         unsigned long           wchan;
         unsigned long           usp;
-        struct pt_regs          *frame;
         unsigned long           fpu_flags;
 #define THREAD_USING_FPU        0x00000001      /* T if this task is using the FPU */
 #define THREAD_HAS_FPU          0x00000002      /* T if this task owns the FPU right now */
@@ -113,7 +111,6 @@ struct thread_struct {
         .sp     = 0,            \
         .a3     = 0,            \
         .wchan  = 0,            \
-        .frame  = NULL,         \
 }
 
 #define INIT_MMAP \
@@ -125,27 +122,20 @@ struct thread_struct {
  * - need to discard the frame stacked by the kernel thread invoking the execve
  *   syscall (see RESTORE_ALL macro)
  */
-#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT) /* FIXME */
-#define start_thread(regs, new_pc, new_sp) do {         \
-        int cpu;                                        \
-        preempt_disable();                              \
-        cpu = CPUID;                                    \
-        set_fs(USER_DS);                                \
-        ___frame[cpu] = current->thread.uregs;          \
-        ___frame[cpu]->epsw = EPSW_nSL | EPSW_IE | EPSW_IM;\
-        ___frame[cpu]->pc = new_pc;                     \
-        ___frame[cpu]->sp = new_sp;                     \
-        preempt_enable();                               \
-} while (0)
-#else  /* CONFIG_SMP && CONFIG_PREEMPT */
-#define start_thread(regs, new_pc, new_sp) do {         \
-        set_fs(USER_DS);                                \
-        __frame = current->thread.uregs;                \
-        __frame->epsw = EPSW_nSL | EPSW_IE | EPSW_IM;   \
-        __frame->pc = new_pc;                           \
-        __frame->sp = new_sp;                           \
-} while (0)
-#endif /* CONFIG_SMP && CONFIG_PREEMPT */
+static inline void start_thread(struct pt_regs *regs,
+                                unsigned long new_pc, unsigned long new_sp)
+{
+        struct thread_info *ti = current_thread_info();
+        struct pt_regs *frame0;
+        set_fs(USER_DS);
+
+        frame0 = thread_info_to_uregs(ti);
+        frame0->epsw = EPSW_nSL | EPSW_IE | EPSW_IM;
+        frame0->pc = new_pc;
+        frame0->sp = new_sp;
+        ti->frame = frame0;
+}
+
 
 /* Free all resources held by a thread. */
 extern void release_thread(struct task_struct *);
diff --git a/arch/mn10300/include/asm/ptrace.h b/arch/mn10300/include/asm/ptrace.h
index c2b77bd3064a..b6961811d445 100644
--- a/arch/mn10300/include/asm/ptrace.h
+++ b/arch/mn10300/include/asm/ptrace.h
@@ -86,12 +86,6 @@ struct pt_regs {
 
 #ifdef __KERNEL__
 
-#ifdef CONFIG_SMP
-extern struct pt_regs *___frame[];      /* current frame pointer */
-#else
-extern struct pt_regs *__frame;         /* current frame pointer */
-#endif
-
 #define user_mode(regs)                 (((regs)->epsw & EPSW_nSL) == EPSW_nSL)
 #define instruction_pointer(regs)       ((regs)->pc)
 #define user_stack_pointer(regs)        ((regs)->sp)
diff --git a/arch/mn10300/include/asm/smp.h b/arch/mn10300/include/asm/smp.h
index b8585b4e8cdf..a3930e43a958 100644
--- a/arch/mn10300/include/asm/smp.h
+++ b/arch/mn10300/include/asm/smp.h
@@ -93,19 +93,6 @@ extern int __cpu_disable(void);
 extern void __cpu_die(unsigned int cpu);
 #endif /* CONFIG_HOTPLUG_CPU */
 
-#ifdef CONFIG_PREEMPT /* FIXME */
-#define __frame                                 \
-        ({                                      \
-                struct pt_regs *f;              \
-                preempt_disable();              \
-                f = ___frame[CPUID];            \
-                preempt_enable();               \
-                f;                              \
-        })
-#else
-#define __frame ___frame[CPUID]
-#endif
-
 #endif /* __ASSEMBLY__ */
 #else /* CONFIG_SMP */
 #ifndef __ASSEMBLY__
diff --git a/arch/mn10300/include/asm/thread_info.h b/arch/mn10300/include/asm/thread_info.h
index 2001cb657a95..aa07a4a5d794 100644
--- a/arch/mn10300/include/asm/thread_info.h
+++ b/arch/mn10300/include/asm/thread_info.h
@@ -16,10 +16,6 @@
 
 #include <asm/page.h>
 
-#ifndef __ASSEMBLY__
-#include <asm/processor.h>
-#endif
-
 #define PREEMPT_ACTIVE          0x10000000
 
 #ifdef CONFIG_4KSTACKS
@@ -38,10 +34,14 @@
  *   must also be changed
  */
 #ifndef __ASSEMBLY__
+typedef struct {
+        unsigned long   seg;
+} mm_segment_t;
 
 struct thread_info {
         struct task_struct      *task;          /* main task structure */
         struct exec_domain      *exec_domain;   /* execution domain */
+        struct pt_regs          *frame;         /* current exception frame */
         unsigned long           flags;          /* low level flags */
         __u32                   cpu;            /* current CPU */
         __s32                   preempt_count;  /* 0 => preemptable, <0 => BUG */
@@ -55,6 +55,10 @@ struct thread_info {
         __u8                    supervisor_stack[0];
 };
 
+#define thread_info_to_uregs(ti)                                        \
+        ((struct pt_regs *)                                             \
+         ((unsigned long)ti + THREAD_SIZE - sizeof(struct pt_regs)))
+
 #else /* !__ASSEMBLY__ */
 
 #ifndef __ASM_OFFSETS_H__
@@ -102,6 +106,12 @@ struct thread_info *current_thread_info(void)
         return ti;
 }
 
+static inline __attribute__((const))
+struct pt_regs *current_frame(void)
+{
+        return current_thread_info()->frame;
+}
+
 /* how to get the current stack pointer from C */
 static inline unsigned long current_stack_pointer(void)
 {
diff --git a/arch/mn10300/include/asm/uaccess.h b/arch/mn10300/include/asm/uaccess.h
index 47e7951e6893..679dee0bbd08 100644
--- a/arch/mn10300/include/asm/uaccess.h
+++ b/arch/mn10300/include/asm/uaccess.h
@@ -14,9 +14,8 @@
 /*
  * User space memory access functions
  */
-#include <linux/sched.h>
+#include <linux/thread_info.h>
 #include <asm/page.h>
-#include <asm/pgtable.h>
 #include <asm/errno.h>
 
 #define VERIFY_READ 0
@@ -29,7 +28,6 @@
  *
  * For historical reasons, these macros are grossly misnamed.
  */
-
 #define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
 
 #define KERNEL_XDS      MAKE_MM_SEG(0xBFFFFFFF)