--- /dev/null
+/*
+ * arch/sh/kernel/cpu/sh2/entry.S
+ *
+ * The SH-2 exception entry
+ *
+ * Copyright (C) 2005,2006 Yoshinori Sato
+ * Copyright (C) 2005 AXE,Inc.
+ *
+ * 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.
+ */
+
+#include <linux/linkage.h>
+#include <asm/asm-offsets.h>
+#include <asm/thread_info.h>
+#include <asm/cpu/mmu_context.h>
+#include <asm/unistd.h>
+#include <asm/errno.h>
+#include <asm/page.h>
+
+/* Offsets to the stack */
+OFF_R0 = 0 /* Return value. New ABI also arg4 */
+OFF_R1 = 4 /* New ABI: arg5 */
+OFF_R2 = 8 /* New ABI: arg6 */
+OFF_R3 = 12 /* New ABI: syscall_nr */
+OFF_R4 = 16 /* New ABI: arg0 */
+OFF_R5 = 20 /* New ABI: arg1 */
+OFF_R6 = 24 /* New ABI: arg2 */
+OFF_R7 = 28 /* New ABI: arg3 */
+OFF_SP = (15*4)
+OFF_PC = (16*4)
+OFF_SR = (16*4+2*4)
+OFF_TRA = (16*4+6*4)
+
+#include <asm/entry-macros.S>
+
+ENTRY(exception_handler)
+ ! already saved r0/r1
+ mov.l r2,@-sp
+ mov.l r3,@-sp
+ mov r0,r1
+ cli
+ mov.l $cpu_mode,r2
+ mov.l @r2,r0
+ mov.l @(5*4,r15),r3 ! previous SR
+ shll2 r3 ! set "S" flag
+ rotl r0 ! T <- "S" flag
+ rotl r0 ! "S" flag is LSB
+ rotcr r3 ! T -> r3:b30
+ shlr r3
+ shlr r0
+ bt/s 1f
+ mov.l r3,@(5*4,r15) ! copy cpu mode to SR
+ ! switch to kernel mode
+ mov #1,r0
+ rotr r0
+ rotr r0
+ mov.l r0,@r2 ! enter kernel mode
+ mov.l $current_thread_info,r2
+ mov.l @r2,r2
+ mov #0x20,r0
+ shll8 r0
+ add r2,r0
+ mov r15,r2 ! r2 = user stack top
+ mov r0,r15 ! switch kernel stack
+ add #-4,r15 ! dummy
+ mov.l r1,@-r15 ! TRA
+ sts.l macl, @-r15
+ sts.l mach, @-r15
+ stc.l gbr, @-r15
+ mov.l @(4*4,r2),r0
+ mov.l @(5*4,r2),r1
+ mov.l r1,@-r15 ! original SR
+ sts.l pr,@-r15
+ mov.l r0,@-r15 ! original PC
+ mov r2,r3
+ add #(4+2)*4,r3 ! rewind r0 - r3 + exception frame
+ mov.l r3,@-r15 ! original SP
+ mov.l r14,@-r15
+ mov.l r13,@-r15
+ mov.l r12,@-r15
+ mov.l r11,@-r15
+ mov.l r10,@-r15
+ mov.l r9,@-r15
+ mov.l r8,@-r15
+ mov.l r7,@-r15
+ mov.l r6,@-r15
+ mov.l r5,@-r15
+ mov.l r4,@-r15
+ mov r2,r8 ! copy user -> kernel stack
+ mov.l @r8+,r3
+ mov.l r3,@-r15
+ mov.l @r8+,r2
+ mov.l r2,@-r15
+ mov.l @r8+,r1
+ mov.l r1,@-r15
+ mov.l @r8+,r0
+ bra 2f
+ mov.l r0,@-r15
+1:
+ ! in kernel exception
+ mov #(22-4-4-1)*4+4,r0
+ mov r15,r2
+ sub r0,r15
+ mov.l @r2+,r0 ! old R3
+ mov.l r0,@-r15
+ mov.l @r2+,r0 ! old R2
+ mov.l r0,@-r15
+ mov.l @r2+,r0 ! old R1
+ mov.l r0,@-r15
+ mov.l @r2+,r0 ! old R0
+ mov.l r0,@-r15
+ mov.l @r2+,r3 ! old PC
+ mov.l @r2+,r0 ! old SR
+ add #-4,r2 ! exception frame stub (sr)
+ mov.l r1,@-r2 ! TRA
+ sts.l macl, @-r2
+ sts.l mach, @-r2
+ stc.l gbr, @-r2
+ mov.l r0,@-r2 ! save old SR
+ sts.l pr,@-r2
+ mov.l r3,@-r2 ! save old PC
+ mov r2,r0
+ add #8*4,r0
+ mov.l r0,@-r2 ! save old SP
+ mov.l r14,@-r2
+ mov.l r13,@-r2
+ mov.l r12,@-r2
+ mov.l r11,@-r2
+ mov.l r10,@-r2
+ mov.l r9,@-r2
+ mov.l r8,@-r2
+ mov.l r7,@-r2
+ mov.l r6,@-r2
+ mov.l r5,@-r2
+ mov.l r4,@-r2
+ mov.l @(OFF_R0,r15),r0
+ mov.l @(OFF_R1,r15),r1
+ mov.l @(OFF_R2,r15),r2
+ mov.l @(OFF_R3,r15),r3
+2:
+ mov #OFF_TRA,r8
+ add r15,r8
+ mov.l @r8,r9
+ mov #64,r8
+ cmp/hs r8,r9
+ bt interrupt_entry ! vec >= 64 is interrupt
+ mov #32,r8
+ cmp/hs r8,r9
+ bt trap_entry ! 64 > vec >= 32 is trap
+ mov.l 4f,r8
+ mov r9,r4
+ shll2 r9
+ add r9,r8
+ mov.l @r8,r8
+ mov #0,r9
+ cmp/eq r9,r8
+ bf 3f
+ mov.l 8f,r8 ! unhandled exception
+3:
+ mov.l 5f,r10
+ jmp @r8
+ lds r10,pr
+
+interrupt_entry:
+ mov r9,r4
+ mov.l 6f,r9
+ mov.l 7f,r8
+ jmp @r8
+ lds r9,pr
+
+ .align 2
+4: .long exception_handling_table
+5: .long ret_from_exception
+6: .long ret_from_irq
+7: .long do_IRQ
+8: .long do_exception_error
+
+trap_entry:
+ add #-0x10,r9
+ shll2 r9 ! TRA
+ mov #OFF_TRA,r8
+ add r15,r8
+ mov.l r9,@r8
+ mov r9,r8
+ sti
+ bra system_call
+ nop
+
+ .align 2
+1: .long syscall_exit
+2: .long break_point_trap_software
+3: .long NR_syscalls
+4: .long sys_call_table
+
+#if defined(CONFIG_SH_STANDARD_BIOS)
+ /* Unwind the stack and jmp to the debug entry */
+debug_kernel_fw:
+ mov r15,r0
+ add #(22-4)*4-4,r0
+ ldc.l @r0+,gbr
+ lds.l @r0+,mach
+ lds.l @r0+,macl
+ mov r15,r0
+ mov.l @(OFF_SP,r0),r1
+ mov #OFF_SR,r2
+ mov.l @(r0,r2),r3
+ mov.l r3,@-r1
+ mov #OFF_SP,r2
+ mov.l @(r0,r2),r3
+ mov.l r3,@-r1
+ mov r15,r0
+ add #(22-4)*4-8,r0
+ mov.l 1f,r2
+ mov.l @r2,r2
+ stc sr,r3
+ mov.l r2,@r0
+ mov.l r3,@r0
+ mov.l r1,@(8,r0)
+ mov.l @r15+, r0
+ mov.l @r15+, r1
+ mov.l @r15+, r2
+ mov.l @r15+, r3
+ mov.l @r15+, r4
+ mov.l @r15+, r5
+ mov.l @r15+, r6
+ mov.l @r15+, r7
+ mov.l @r15+, r8
+ mov.l @r15+, r9
+ mov.l @r15+, r10
+ mov.l @r15+, r11
+ mov.l @r15+, r12
+ mov.l @r15+, r13
+ mov.l @r15+, r14
+ add #8,r15
+ lds.l @r15+, pr
+ rte
+ mov.l @r15+,r15
+ .align 2
+1: .long gdb_vbr_vector
+#endif /* CONFIG_SH_STANDARD_BIOS */
+
+ENTRY(address_error_handler)
+ mov r15,r4 ! regs
+ add #4,r4
+ mov #OFF_PC,r0
+ mov.l @(r0,r15),r6 ! pc
+ mov.l 1f,r0
+ jmp @r0
+ mov #0,r5 ! writeaccess is unknown
+ .align 2
+
+1: .long do_address_error
+
+restore_all:
+ cli
+ mov r15,r0
+ mov.l $cpu_mode,r2
+ mov #OFF_SR,r3
+ mov.l @(r0,r3),r1
+ mov.l r1,@r2
+ shll2 r1 ! clear MD bit
+ shlr2 r1
+ mov.l @(OFF_SP,r0),r2
+ add #-8,r2
+ mov.l r2,@(OFF_SP,r0) ! point exception frame top
+ mov.l r1,@(4,r2) ! set sr
+ mov #OFF_PC,r3
+ mov.l @(r0,r3),r1
+ mov.l r1,@r2 ! set pc
+ add #4*16+4,r0
+ lds.l @r0+,pr
+ add #4,r0 ! skip sr
+ ldc.l @r0+,gbr
+ lds.l @r0+,mach
+ lds.l @r0+,macl
+ get_current_thread_info r0, r1
+ mov.l $current_thread_info,r1
+ mov.l r0,@r1
+ mov.l @r15+,r0
+ mov.l @r15+,r1
+ mov.l @r15+,r2
+ mov.l @r15+,r3
+ mov.l @r15+,r4
+ mov.l @r15+,r5
+ mov.l @r15+,r6
+ mov.l @r15+,r7
+ mov.l @r15+,r8
+ mov.l @r15+,r9
+ mov.l @r15+,r10
+ mov.l @r15+,r11
+ mov.l @r15+,r12
+ mov.l @r15+,r13
+ mov.l @r15+,r14
+ mov.l @r15,r15
+ rte
+ nop
+2:
+ mov.l 1f,r8
+ mov.l 2f,r9
+ jmp @r9
+ lds r8,pr
+
+ .align 2
+$current_thread_info:
+ .long __current_thread_info
+$cpu_mode:
+ .long __cpu_mode
+
+! common exception handler
+#include "../../entry-common.S"
+
+ .data
+! cpu operation mode
+! bit30 = MD (compatible SH3/4)
+__cpu_mode:
+ .long 0x40000000
+
+ .section .bss
+__current_thread_info:
+ .long 0
+
+ENTRY(exception_handling_table)
+ .space 4*32
--- /dev/null
+/*
+ * arch/sh/kernel/cpu/sh2/ex.S
+ *
+ * The SH-2 exception vector table
+ *
+ * Copyright (C) 2005 Yoshinori Sato
+ *
+ * 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.
+ */
+
+#include <linux/linkage.h>
+
+!
+! convert Exception Vector to Exception Number
+!
+exception_entry:
+no = 0
+ .rept 256
+ mov.l r0,@-sp
+ mov #no,r0
+ bra exception_trampoline
+ and #0xff,r0
+no = no + 1
+ .endr
+exception_trampoline:
+ mov.l r1,@-sp
+ mov.l $exception_handler,r1
+ jmp @r1
+
+ .align 2
+$exception_entry:
+ .long exception_entry
+$exception_handler:
+ .long exception_handler
+!
+! Exception Vector Base
+!
+ .align 2
+ENTRY(vbr_base)
+vector = 0
+ .rept 256
+ .long exception_entry + vector * 8
+vector = vector + 1
+ .endr
# Makefile for the Linux/SuperH SH-3 backends.
#
-obj-y := ex.o probe.o
+obj-y := ex.o probe.o entry.o
# CPU subtype setup
obj-$(CONFIG_CPU_SUBTYPE_SH7705) += setup-sh7705.o
/*
- * linux/arch/sh/entry.S
+ * arch/sh/kernel/entry.S
*
* Copyright (C) 1999, 2000, 2002 Niibe Yutaka
* Copyright (C) 2003 - 2006 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.
- *
*/
#include <linux/sys.h>
#include <linux/errno.h>
#define k_g_imask r6_bank /* r6_bank1 */
#define current r7 /* r7_bank1 */
+#include <asm/entry-macros.S>
+
/*
* Kernel mode register usage:
* k0 scratch
! this first version depends *much* on C implementation.
!
-#define CLI() \
- stc sr, r0; \
- or #0xf0, r0; \
- ldc r0, sr
-
-#define STI() \
- mov.l __INV_IMASK, r11; \
- stc sr, r10; \
- and r11, r10; \
- stc k_g_imask, r11; \
- or r11, r10; \
- ldc r10, sr
-
-#if defined(CONFIG_PREEMPT)
-# define preempt_stop() CLI()
-#else
-# define preempt_stop()
-# define resume_kernel restore_all
-#endif
-
#if defined(CONFIG_MMU)
.align 2
ENTRY(tlb_miss_load)
lds r10, pr
rts
nop
-0: STI()
+0: sti
mov.l 3f, r0
mov r9, r6
mov r8, r5
2: .long do_address_error
#endif /* CONFIG_MMU */
-#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 */
-
#if defined(CONFIG_SH_STANDARD_BIOS)
/* Unwind the stack and jmp to the debug entry */
debug_kernel_fw:
2: .long gdb_vbr_vector
#endif /* CONFIG_SH_STANDARD_BIOS */
-#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?
- bt/s resume_kernel ! Yes, it's from kernel, go back soon
- GET_THREAD_INFO(r8)
-
-#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
- mova restore_all, 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
-
- .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
-
-/*
- * 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)
- mov.l 1f, r9
- mov.l @r9, r8 ! Read from TRA (Trap Address) Register
- !
- ! 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
- bf/s good_system_call
- GET_THREAD_INFO(r8)
-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_THREAD_INFO(r8)
- mov.l @(TI_FLAGS,r8), r0 ! current_thread_info->flags
- tst #_TIF_ALLWORK_MASK, r0
- bf syscall_exit_work
restore_all:
mov.l @r15+, r0
mov.l @r15+, r1
!
! Calculate new SR value
mov k3, k2 ! original SR value
- mov.l 9f, k1
+ mov #0xf0, k1
+ extu.b k1, k1
+ not k1, k1
and k1, k2 ! Mask orignal SR value
!
mov k3, k0 ! Calculate IMASK-bits
nop
.align 2
-1: .long TRA
-2: .long NR_syscalls
-3: .long sys_call_table
-4: .long do_syscall_trace
5: .long 0x00001000 ! DSP
7: .long 0x30000000
-9:
-__INV_IMASK:
- .long 0xffffff0f ! ~(IMASK)
+! common exception handler
+#include "../../entry.S"
+
! Exception Vector Base
!
! Should be aligned page boundary.
! Save the user registers on the stack.
mov.l k2, @-r15 ! EXPEVT
- mov #-1, k4
+ mov #-1, k4
mov.l k4, @-r15 ! set TRA (default: -1)
!
sts.l macl, @-r15
# Makefile for the Linux/SuperH SH-4 backends.
#
-obj-y := ex.o probe.o
+obj-y := ex.o probe.o common.o
+common-y += $(addprefix ../sh3/, entry.o)
obj-$(CONFIG_SH_FPU) += fpu.o
obj-$(CONFIG_SH_STORE_QUEUES) += sq.o
--- /dev/null
+/* $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
ldc r0, sr
! Initialize global interrupt mask
mov #0, r0
+#ifdef CONFIG_CPU_HAS_SR_RB
ldc r0, r6_bank
-
+#endif
+
/*
* Prefetch if possible to reduce cache miss penalty.
*
mov #(THREAD_SIZE >> 8), r1
shll8 r1 ! r1 = THREAD_SIZE
sub r1, r0 !
+#ifdef CONFIG_CPU_HAS_SR_RB
ldc r0, r7_bank ! ... and initial thread_info
-
+#endif
+
! Clear BSS area
mov.l 3f, r1
add #4, r1
nop
.balign 4
+#if defined(CONFIG_CPU_SH2)
+1: .long 0x000000F0 ! IMASK=0xF
+#else
1: .long 0x400080F0 ! MD=1, RB=0, BL=0, FD=1, IMASK=0xF
+#endif
2: .long init_thread_union+THREAD_SIZE
3: .long __bss_start
4: .long _end
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