m68k: remove thread_info struct from thread struct

Currently on m68k we have a comeplete thread_info structure stored inside
of the thread_struct, and we also have it in the initial part of the kernel
stack. Mostly the code currently uses the one inside of the thread_struct,
only using the "task" pointer from the stack based one.

This is wasteful and confusing, we should only have the single instance of
thread_info inside the stack page. And this is the norm for all other
architectures.

This change makes m68k handle thread_info consistently on both MMU enabled
and non-MMU setups.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>

2 files changed, 22 insertions, 11 deletions

diff --git a/arch/m68k/kernel/asm-offsets.c b/arch/m68k/kernel/asm-offsets.c
index f6a54e203e8e..a972b00cd77d 100644
--- a/arch/m68k/kernel/asm-offsets.c
+++ b/arch/m68k/kernel/asm-offsets.c
@@ -24,7 +24,7 @@ int main(void)
         /* offsets into the task struct */
         DEFINE(TASK_THREAD, offsetof(struct task_struct, thread));
         DEFINE(TASK_MM, offsetof(struct task_struct, mm));
-        DEFINE(TASK_INFO, offsetof(struct task_struct, thread.info));
+        DEFINE(TASK_STACK, offsetof(struct task_struct, stack));
 
         /* offsets into the thread struct */
         DEFINE(THREAD_KSP, offsetof(struct thread_struct, ksp));
diff --git a/arch/m68k/kernel/entry_mm.S b/arch/m68k/kernel/entry_mm.S
index c713f514843d..675a854966a6 100644
--- a/arch/m68k/kernel/entry_mm.S
+++ b/arch/m68k/kernel/entry_mm.S
@@ -99,7 +99,8 @@ do_trace_exit:
         jra     .Lret_from_exception
 
 ENTRY(ret_from_signal)
-        tstb    %curptr@(TASK_INFO+TINFO_FLAGS+2)
+        movel   %curptr@(TASK_STACK),%a1
+        tstb    %a1@(TINFO_FLAGS+2)
         jge     1f
         jbsr    syscall_trace
 1:      RESTORE_SWITCH_STACK
@@ -120,11 +121,13 @@ ENTRY(system_call)
         SAVE_ALL_SYS
 
         GET_CURRENT(%d1)
+        movel   %d1,%a1
+
         | save top of frame
         movel   %sp,%curptr@(TASK_THREAD+THREAD_ESP0)
 
         | syscall trace?
-        tstb    %curptr@(TASK_INFO+TINFO_FLAGS+2)
+        tstb    %a1@(TINFO_FLAGS+2)
         jmi     do_trace_entry
         cmpl    #NR_syscalls,%d0
         jcc     badsys
@@ -133,7 +136,8 @@ syscall:
         movel   %d0,%sp@(PT_OFF_D0)     | save the return value
 ret_from_syscall:
         |oriw   #0x0700,%sr
-        movew   %curptr@(TASK_INFO+TINFO_FLAGS+2),%d0
+        movel   %curptr@(TASK_STACK),%a1
+        movew   %a1@(TINFO_FLAGS+2),%d0
         jne     syscall_exit_work
 1:      RESTORE_ALL
 
@@ -159,7 +163,8 @@ ENTRY(ret_from_exception)
         andw    #ALLOWINT,%sr
 
 resume_userspace:
-        moveb   %curptr@(TASK_INFO+TINFO_FLAGS+3),%d0
+        movel   %curptr@(TASK_STACK),%a1
+        moveb   %a1@(TINFO_FLAGS+3),%d0
         jne     exit_work
 1:      RESTORE_ALL
 
@@ -199,7 +204,8 @@ do_delayed_trace:
 ENTRY(auto_inthandler)
         SAVE_ALL_INT
         GET_CURRENT(%d0)
-        addqb   #1,%curptr@(TASK_INFO+TINFO_PREEMPT+1)
+        movel   %d0,%a1
+        addqb   #1,%a1@(TINFO_PREEMPT+1)
                                         |  put exception # in d0
         bfextu  %sp@(PT_OFF_FORMATVEC){#4,#10},%d0
         subw    #VEC_SPUR,%d0
@@ -211,7 +217,8 @@ auto_irqhandler_fixup = . + 2
         addql   #8,%sp                  |  pop parameters off stack
 
 ret_from_interrupt:
-        subqb   #1,%curptr@(TASK_INFO+TINFO_PREEMPT+1)
+        movel   %curptr@(TASK_STACK),%a1
+        subqb   #1,%a1@(TINFO_PREEMPT+1)
         jeq     ret_from_last_interrupt
 2:      RESTORE_ALL
 
@@ -232,7 +239,8 @@ ret_from_last_interrupt:
 ENTRY(user_inthandler)
         SAVE_ALL_INT
         GET_CURRENT(%d0)
-        addqb   #1,%curptr@(TASK_INFO+TINFO_PREEMPT+1)
+        movel   %d0,%a1
+        addqb   #1,%a1@(TINFO_PREEMPT+1)
                                         |  put exception # in d0
         bfextu  %sp@(PT_OFF_FORMATVEC){#4,#10},%d0
 user_irqvec_fixup = . + 2
@@ -243,7 +251,8 @@ user_irqvec_fixup = . + 2
         jsr     do_IRQ                  |  process the IRQ
         addql   #8,%sp                  |  pop parameters off stack
 
-        subqb   #1,%curptr@(TASK_INFO+TINFO_PREEMPT+1)
+        movel   %curptr@(TASK_STACK),%a1
+        subqb   #1,%a1@(TINFO_PREEMPT+1)
         jeq     ret_from_last_interrupt
         RESTORE_ALL
 
@@ -252,13 +261,15 @@ user_irqvec_fixup = . + 2
 ENTRY(bad_inthandler)
         SAVE_ALL_INT
         GET_CURRENT(%d0)
-        addqb   #1,%curptr@(TASK_INFO+TINFO_PREEMPT+1)
+        movel   %d0,%a1
+        addqb   #1,%a1@(TINFO_PREEMPT+1)
 
         movel   %sp,%sp@-
         jsr     handle_badint
         addql   #4,%sp
 
-        subqb   #1,%curptr@(TASK_INFO+TINFO_PREEMPT+1)
+        movel   %curptr@(TASK_STACK),%a1
+        subqb   #1,%a1@(TINFO_PREEMPT+1)
         jeq     ret_from_last_interrupt
         RESTORE_ALL