1 files changed, 372 insertions, 0 deletions

diff --git a/arch/sh/kernel/entry-common.S b/arch/sh/kernel/entry-common.S
new file mode 100644
index 000000000000..5bc7fa91d095
--- /dev/null
+++ b/arch/sh/kernel/entry-common.S
@@ -0,0 +1,372 @@
+/* $Id: entry.S,v 1.37 2004/06/11 13:02:46 doyu Exp $
+ *
+ *  linux/arch/sh/entry.S
+ *
+ *  Copyright (C) 1999, 2000, 2002  Niibe Yutaka
+ *  Copyright (C) 2003  Paul Mundt
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ */
+
+! NOTE:
+! GNU as (as of 2.9.1) changes bf/s into bt/s and bra, when the address
+! to be jumped is too far, but it causes illegal slot exception.
+
+/*      
+ * entry.S contains the system-call and fault low-level handling routines.
+ * This also contains the timer-interrupt handler, as well as all interrupts
+ * and faults that can result in a task-switch.
+ *
+ * NOTE: This code handles signal-recognition, which happens every time
+ * after a timer-interrupt and after each system call.
+ *
+ * NOTE: This code uses a convention that instructions in the delay slot
+ * of a transfer-control instruction are indented by an extra space, thus:
+ *
+ *    jmp       @k0         ! control-transfer instruction
+ *     ldc      k1, ssr     ! delay slot
+ *
+ * Stack layout in 'ret_from_syscall':
+ *      ptrace needs to have all regs on the stack.
+ *      if the order here is changed, it needs to be
+ *      updated in ptrace.c and ptrace.h
+ *
+ *      r0
+ *      ...
+ *      r15 = stack pointer
+ *      spc
+ *      pr
+ *      ssr
+ *      gbr
+ *      mach
+ *      macl
+ *      syscall #
+ *
+ */
+
+#if defined(CONFIG_PREEMPT)
+#  define preempt_stop()        cli
+#else
+#  define preempt_stop()
+#  define resume_kernel         __restore_all
+#endif
+
+#if defined(CONFIG_SH_STANDARD_BIOS) || defined(CONFIG_SH_KGDB)
+! Handle kernel debug if either kgdb (SW) or gdb-stub (FW) is present.
+! If both are configured, handle the debug traps (breakpoints) in SW,
+! but still allow BIOS traps to FW.
+
+        .align  2
+debug_kernel:
+#if defined(CONFIG_SH_STANDARD_BIOS) && defined(CONFIG_SH_KGDB)
+        /* Force BIOS call to FW (debug_trap put TRA in r8) */
+        mov     r8,r0
+        shlr2   r0
+        cmp/eq  #0x3f,r0
+        bt      debug_kernel_fw
+#endif /* CONFIG_SH_STANDARD_BIOS && CONFIG_SH_KGDB */
+
+debug_enter:            
+#if defined(CONFIG_SH_KGDB)
+        /* Jump to kgdb, pass stacked regs as arg */
+debug_kernel_sw:
+        mov.l   3f, r0
+        jmp     @r0
+         mov    r15, r4
+        .align  2
+3:      .long   kgdb_handle_exception
+#endif /* CONFIG_SH_KGDB */
+
+#endif /* CONFIG_SH_STANDARD_BIOS || CONFIG_SH_KGDB */
+
+
+        .align  2
+debug_trap:     
+#if defined(CONFIG_SH_STANDARD_BIOS) || defined(CONFIG_SH_KGDB)
+        mov     #OFF_SR, r0
+        mov.l   @(r0,r15), r0           ! get status register
+        shll    r0
+        shll    r0                      ! kernel space?
+        bt/s    debug_kernel
+#endif
+         mov.l  @r15, r0                ! Restore R0 value
+        mov.l   1f, r8
+        jmp     @r8
+         nop
+
+        .align  2
+ENTRY(exception_error)
+        !
+        sti
+        mov.l   2f, r0
+        jmp     @r0
+         nop
+
+!
+        .align  2
+1:      .long   break_point_trap_software
+2:      .long   do_exception_error
+
+        .align  2
+ret_from_exception:
+        preempt_stop()
+ENTRY(ret_from_irq)
+        !
+        mov     #OFF_SR, r0
+        mov.l   @(r0,r15), r0   ! get status register
+        shll    r0
+        shll    r0              ! kernel space?
+        get_current_thread_info r8, r0
+        bt      resume_kernel   ! Yes, it's from kernel, go back soon
+
+#ifdef CONFIG_PREEMPT
+        bra     resume_userspace
+         nop
+ENTRY(resume_kernel)
+        mov.l   @(TI_PRE_COUNT,r8), r0  ! current_thread_info->preempt_count
+        tst     r0, r0
+        bf      noresched
+need_resched:
+        mov.l   @(TI_FLAGS,r8), r0      ! current_thread_info->flags
+        tst     #_TIF_NEED_RESCHED, r0  ! need_resched set?
+        bt      noresched
+
+        mov     #OFF_SR, r0
+        mov.l   @(r0,r15), r0           ! get status register
+        and     #0xf0, r0               ! interrupts off (exception path)?
+        cmp/eq  #0xf0, r0
+        bt      noresched
+
+        mov.l   1f, r0
+        mov.l   r0, @(TI_PRE_COUNT,r8)
+
+        sti
+        mov.l   2f, r0
+        jsr     @r0
+         nop
+        mov     #0, r0
+        mov.l   r0, @(TI_PRE_COUNT,r8)
+        cli
+
+        bra     need_resched
+         nop
+noresched:
+        bra     __restore_all
+         nop
+
+        .align 2
+1:      .long   PREEMPT_ACTIVE
+2:      .long   schedule
+#endif
+
+ENTRY(resume_userspace)
+        ! r8: current_thread_info
+        cli
+        mov.l   @(TI_FLAGS,r8), r0              ! current_thread_info->flags
+        tst     #_TIF_WORK_MASK, r0
+        bt/s    __restore_all
+         tst    #_TIF_NEED_RESCHED, r0
+
+        .align  2
+work_pending:
+        ! r0: current_thread_info->flags
+        ! r8: current_thread_info
+        ! t:  result of "tst    #_TIF_NEED_RESCHED, r0"
+        bf/s    work_resched
+         tst    #(_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK), r0
+work_notifysig:
+        bt/s    __restore_all
+         mov    r15, r4
+        mov     r12, r5         ! set arg1(save_r0)
+        mov     r0, r6
+        mov.l   2f, r1
+        mov.l   3f, r0
+        jmp     @r1
+         lds    r0, pr
+work_resched:
+#ifndef CONFIG_PREEMPT
+        ! gUSA handling
+        mov.l   @(OFF_SP,r15), r0       ! get user space stack pointer
+        mov     r0, r1
+        shll    r0
+        bf/s    1f
+         shll   r0
+        bf/s    1f
+         mov    #OFF_PC, r0
+        !                                 SP >= 0xc0000000 : gUSA mark
+        mov.l   @(r0,r15), r2           ! get user space PC (program counter)
+        mov.l   @(OFF_R0,r15), r3       ! end point
+        cmp/hs  r3, r2                  ! r2 >= r3? 
+        bt      1f
+        add     r3, r1                  ! rewind point #2
+        mov.l   r1, @(r0,r15)           ! reset PC to rewind point #2
+        !
+1:
+#endif
+        mov.l   1f, r1
+        jsr     @r1                             ! schedule
+         nop
+        cli
+        !
+        mov.l   @(TI_FLAGS,r8), r0              ! current_thread_info->flags
+        tst     #_TIF_WORK_MASK, r0
+        bt      __restore_all
+        bra     work_pending
+         tst    #_TIF_NEED_RESCHED, r0
+
+        .align  2
+1:      .long   schedule
+2:      .long   do_notify_resume
+3:      .long   restore_all
+
+        .align  2
+syscall_exit_work:
+        ! r0: current_thread_info->flags
+        ! r8: current_thread_info
+        tst     #_TIF_SYSCALL_TRACE, r0
+        bt/s    work_pending
+         tst    #_TIF_NEED_RESCHED, r0
+        sti
+        ! XXX setup arguments...
+        mov.l   4f, r0                  ! do_syscall_trace
+        jsr     @r0
+         nop
+        bra     resume_userspace
+         nop
+
+        .align  2
+syscall_trace_entry:
+        !                       Yes it is traced.
+        ! XXX setup arguments...
+        mov.l   4f, r11         ! Call do_syscall_trace which notifies
+        jsr     @r11            ! superior (will chomp R[0-7])
+         nop
+        !                       Reload R0-R4 from kernel stack, where the
+        !                       parent may have modified them using
+        !                       ptrace(POKEUSR).  (Note that R0-R2 are
+        !                       used by the system call handler directly
+        !                       from the kernel stack anyway, so don't need
+        !                       to be reloaded here.)  This allows the parent
+        !                       to rewrite system calls and args on the fly.
+        mov.l   @(OFF_R4,r15), r4   ! arg0
+        mov.l   @(OFF_R5,r15), r5
+        mov.l   @(OFF_R6,r15), r6
+        mov.l   @(OFF_R7,r15), r7   ! arg3
+        mov.l   @(OFF_R3,r15), r3   ! syscall_nr
+        !                   Arrange for do_syscall_trace to be called
+        !                   again as the system call returns.
+        mov.l   2f, r10                 ! Number of syscalls
+        cmp/hs  r10, r3
+        bf      syscall_call
+        mov     #-ENOSYS, r0
+        bra     syscall_exit
+         mov.l  r0, @(OFF_R0,r15)       ! Return value
+
+__restore_all:
+        mov.l   1f,r0
+        jmp     @r0
+         nop
+
+        .align  2
+1:      .long   restore_all
+
+/*
+ * Syscall interface:
+ *
+ *      Syscall #: R3
+ *      Arguments #0 to #3: R4--R7
+ *      Arguments #4 to #6: R0, R1, R2
+ *      TRA: (number of arguments + 0x10) x 4
+ *
+ * This code also handles delegating other traps to the BIOS/gdb stub
+ * according to:
+ *
+ * Trap number
+ * (TRA>>2)         Purpose
+ * --------         -------
+ * 0x0-0xf          old syscall ABI
+ * 0x10-0x1f        new syscall ABI
+ * 0x20-0xff        delegated through debug_trap to BIOS/gdb stub.
+ *
+ * Note: When we're first called, the TRA value must be shifted
+ * right 2 bits in order to get the value that was used as the "trapa"
+ * argument.
+ */
+
+        .align  2
+        .globl  ret_from_fork
+ret_from_fork:
+        mov.l   1f, r8
+        jsr     @r8
+         mov    r0, r4
+        bra     syscall_exit
+         nop
+        .align  2
+1:      .long   schedule_tail
+        !
+ENTRY(system_call)
+#if !defined(CONFIG_CPU_SH2)
+        mov.l   1f, r9
+        mov.l   @r9, r8         ! Read from TRA (Trap Address) Register
+#endif
+        !
+        ! Is the trap argument >= 0x20? (TRA will be >= 0x80)
+        mov     #0x7f, r9
+        cmp/hi  r9, r8
+        bt/s    0f
+         mov    #OFF_TRA, r9
+        add     r15, r9
+        !
+        mov.l   r8, @r9                 ! set TRA value to tra
+        sti
+        !                   Call the system call handler through the table.
+        !                   First check for bad syscall number
+        mov     r3, r9
+        mov.l   2f, r8                  ! Number of syscalls
+        cmp/hs  r8, r9
+        get_current_thread_info r8, r10
+        bf      good_system_call
+syscall_badsys:                 ! Bad syscall number
+        mov     #-ENOSYS, r0
+        bra     resume_userspace
+         mov.l  r0, @(OFF_R0,r15)       ! Return value
+        !
+0:
+        bra     debug_trap
+         nop
+        !
+good_system_call:               ! Good syscall number
+        mov.l   @(TI_FLAGS,r8), r8
+        mov     #_TIF_SYSCALL_TRACE, r10
+        tst     r10, r8
+        bf      syscall_trace_entry
+        !
+syscall_call:
+        shll2   r9              ! x4
+        mov.l   3f, r8          ! Load the address of sys_call_table
+        add     r8, r9
+        mov.l   @r9, r8
+        jsr     @r8             ! jump to specific syscall handler
+         nop
+        mov.l   @(OFF_R0,r15), r12              ! save r0
+        mov.l   r0, @(OFF_R0,r15)               ! save the return value
+        !
+syscall_exit:
+        cli
+        !
+        get_current_thread_info r8, r0
+        mov.l   @(TI_FLAGS,r8), r0              ! current_thread_info->flags
+        tst     #_TIF_ALLWORK_MASK, r0
+        bf      syscall_exit_work
+        bra     __restore_all
+         nop
+        .align  2
+#if !defined(CONFIG_CPU_SH2)
+1:      .long   TRA
+#endif
+2:      .long   NR_syscalls
+3:      .long   sys_call_table
+4:      .long   do_syscall_trace