/* SPDX-License-Identifier: GPL-2.0 */
/*
*
* linux/arch/h8300/kernel/entry.S
*
* Yoshinori Sato <ysato@users.sourceforge.jp>
* David McCullough <davidm@snapgear.com>
*
*/
/*
* entry.S
* include exception/interrupt gateway
* system call entry
*/
#include <linux/sys.h>
#include <asm/unistd.h>
#include <asm/setup.h>
#include <asm/segment.h>
#include <asm/linkage.h>
#include <asm/asm-offsets.h>
#include <asm/thread_info.h>
#include <asm/errno.h>
#if defined(CONFIG_CPU_H8300H)
#define USERRET 8
INTERRUPTS = 64
.h8300h
.macro SHLL2 reg
shll.l \reg
shll.l \reg
.endm
.macro SHLR2 reg
shlr.l \reg
shlr.l \reg
.endm
.macro SAVEREGS
mov.l er0,@-sp
mov.l er1,@-sp
mov.l er2,@-sp
mov.l er3,@-sp
.endm
.macro RESTOREREGS
mov.l @sp+,er3
mov.l @sp+,er2
.endm
.macro SAVEEXR
.endm
.macro RESTOREEXR
.endm
#endif
#if defined(CONFIG_CPU_H8S)
#define USERRET 10
#define USEREXR 8
INTERRUPTS = 128
.h8300s
.macro SHLL2 reg
shll.l #2,\reg
.endm
.macro SHLR2 reg
shlr.l #2,\reg
.endm
.macro SAVEREGS
stm.l er0-er3,@-sp
.endm
.macro RESTOREREGS
ldm.l @sp+,er2-er3
.endm
.macro SAVEEXR
mov.w @(USEREXR:16,er0),r1
mov.w r1,@(LEXR-LER3:16,sp) /* copy EXR */
.endm
.macro RESTOREEXR
mov.w @(LEXR-LER1:16,sp),r1 /* restore EXR */
mov.b r1l,r1h
mov.w r1,@(USEREXR:16,er0)
.endm
#endif
/* CPU context save/restore macros. */
.macro SAVE_ALL
mov.l er0,@-sp
stc ccr,r0l /* check kernel mode */
btst #4,r0l
bne 5f
/* user mode */
mov.l sp,@_sw_usp
mov.l @sp,er0 /* restore saved er0 */
orc #0x10,ccr /* switch kernel stack */
mov.l @_sw_ksp,sp
sub.l #(LRET-LORIG),sp /* allocate LORIG - LRET */
SAVEREGS
mov.l @_sw_usp,er0
mov.l @(USERRET:16,er0),er1 /* copy the RET addr */
mov.l er1,@(LRET-LER3:16,sp)
SAVEEXR
mov.l @(LORIG-LER3:16,sp),er0
mov.l er0,@(LER0-LER3:16,sp) /* copy ER0 */
mov.w e1,r1 /* e1 highbyte = ccr */
and #0xef,r1h /* mask mode? flag */
bra 6f
5:
/* kernel mode */
mov.l @sp,er0 /* restore saved er0 */
subs #2,sp /* set dummy ccr */
subs #4,sp /* set dummp sp */
SAVEREGS
mov.w @(LRET-LER3:16,sp),r1 /* copy old ccr */
6:
mov.b r1h,r1l
mov.b #0,r1h
mov.w r1,@(LCCR-LER3:16,sp) /* set ccr */
mov.l @_sw_usp,er2
mov.l er2,@(LSP-LER3:16,sp) /* set usp */
mov.l er6,@-sp /* syscall arg #6 */
mov.l er5,@-sp /* syscall arg #5 */
mov.l er4,@-sp /* syscall arg #4 */
.endm /* r1 = ccr */
.macro RESTORE_ALL
mov.l @sp+,er4
mov.l @sp+,er5
mov.l @sp+,er6
RESTOREREGS
mov.w @(LCCR-LER1:16,sp),r0 /* check kernel mode */
btst #4,r0l
bne 7f
orc #0xc0,ccr
mov.l @(LSP-LER1:16,sp),er0
mov.l @(LER0-LER1:16,sp),er1 /* restore ER0 */
mov.l er1,@er0
RESTOREEXR
mov.w @(LCCR-LER1:16,sp),r1 /* restore the RET addr */
mov.b r1l,r1h
mov.b @(LRET+1-LER1:16,sp),r1l
mov.w r1,e1
mov.w @(LRET+2-LER1:16,sp),r1
mov.l er1,@(USERRET:16,er0)
mov.l @sp+,er1
add.l #(LRET-LER1),sp /* remove LORIG - LRET */
mov.l sp,@_sw_ksp
andc #0xef,ccr /* switch to user mode */
mov.l er0,sp
bra 8f
7:
mov.l @sp+,er1
add.l #10,sp
8:
mov.l @sp+,er0
adds #4,sp /* remove the sw created LVEC */
rte
.endm
.globl _system_call
.globl ret_from_exception
.globl ret_from_fork
.globl ret_from_kernel_thread
.globl ret_from_interrupt
.globl _interrupt_redirect_table
.globl _sw_ksp,_sw_usp
.globl _resume
.globl _interrupt_entry
.globl _trace_break
.globl _nmi
#if defined(CONFIG_ROMKERNEL)
.section .int_redirect,"ax"
_interrupt_redirect_table:
#if defined(CONFIG_CPU_H8300H)
.rept 7
.long 0
.endr
#endif
#if defined(CONFIG_CPU_H8S)
.rept 5
.long 0
.endr
jmp @_trace_break
.long 0
#endif
jsr @_interrupt_entry /* NMI */
jmp @_system_call /* TRAPA #0 (System call) */
.long 0
#if defined(CONFIG_KGDB)
jmp @_kgdb_trap
#else
.long 0
#endif
jmp @_trace_break /* TRAPA #3 (breakpoint) */
.rept INTERRUPTS-12
jsr @_interrupt_entry
.endr
#endif
#if defined(CONFIG_RAMKERNEL)
.globl _interrupt_redirect_table
.section .bss
_interrupt_redirect_table:
.space 4
#endif
.section .text
.align 2
_interrupt_entry:
SAVE_ALL
/* r1l is saved ccr */
mov.l sp,er0
add.l #LVEC,er0
btst #4,r1l
bne 1f
/* user LVEC */
mov.l @_sw_usp,er0
adds #4,er0
1:
mov.l @er0,er0 /* LVEC address */
#if defined(CONFIG_ROMKERNEL)
sub.l #_interrupt_redirect_table,er0
#endif
#if defined(CONFIG_RAMKERNEL)
mov.l @_interrupt_redirect_table,er1
sub.l er1,er0
#endif
SHLR2 er0
dec.l #1,er0
mov.l sp,er1
subs #4,er1 /* adjust ret_pc */
#if defined(CONFIG_CPU_H8S)
orc #7,exr
#endif
jsr @do_IRQ
jmp @ret_from_interrupt
_system_call:
subs #4,sp /* dummy LVEC */
SAVE_ALL
/* er0: syscall nr */
andc #0xbf,ccr
mov.l er0,er4
/* save top of frame */
mov.l sp,er0
jsr @set_esp0
andc #0x3f,ccr
mov.l sp,er2
and.w #0xe000,r2
mov.l @(TI_FLAGS:16,er2),er2
and.w #_TIF_WORK_SYSCALL_MASK,r2
beq 1f
mov.l sp,er0
jsr @do_syscall_trace_enter
1:
cmp.l #__NR_syscalls,er4
bcc badsys
SHLL2 er4
mov.l #_sys_call_table,er0
add.l er4,er0
mov.l @er0,er4
beq ret_from_exception:16
mov.l @(LER1:16,sp),er0
mov.l @(LER2:16,sp),er1
mov.l @(LER3:16,sp),er2
jsr @er4
mov.l er0,@(LER0:16,sp) /* save the return value */
mov.l sp,er2
and.w #0xe000,r2
mov.l @(TI_FLAGS:16,er2),er2
and.w #_TIF_WORK_SYSCALL_MASK,r2
beq 2f
mov.l sp,er0
jsr @do_syscall_trace_leave
2:
orc #0xc0,ccr
bra resume_userspace
badsys:
mov.l #-ENOSYS,er0
mov.l er0,@(LER0:16,sp)
bra resume_userspace
#if !defined(CONFIG_PREEMPT)
#define resume_kernel restore_all
#endif
ret_from_exception:
#if defined(CONFIG_PREEMPT)
orc #0xc0,ccr
#endif
ret_from_interrupt:
mov.b @(LCCR+1:16,sp),r0l
btst #4,r0l
bne resume_kernel:16 /* return from kernel */
resume_userspace:
andc #0xbf,ccr
mov.l sp,er4
and.w #0xe000,r4 /* er4 <- current thread info */
mov.l @(TI_FLAGS:16,er4),er1
and.l #_TIF_WORK_MASK,er1
beq restore_all:8
work_pending:
btst #TIF_NEED_RESCHED,r1l
bne work_resched:8
/* work notifysig */
mov.l sp,er0
subs #4,er0 /* er0: pt_regs */
jsr @do_notify_resume
bra resume_userspace:8
work_resched:
mov.l sp,er0
jsr @set_esp0
jsr @schedule
bra resume_userspace:8
restore_all:
RESTORE_ALL /* Does RTE */
#if defined(CONFIG_PREEMPT)
resume_kernel:
mov.l @(TI_PRE_COUNT:16,er4),er0
bne restore_all:8
need_resched:
mov.l @(TI_FLAGS:16,er4),er0
btst #TIF_NEED_RESCHED,r0l
beq restore_all:8
mov.b @(LCCR+1:16,sp),r0l /* Interrupt Enabled? */
bmi restore_all:8
mov.l sp,er0
jsr @set_esp0
jsr @preempt_schedule_irq
bra need_resched:8
#endif
ret_from_fork:
mov.l er2,er0
jsr @schedule_tail
jmp @ret_from_exception
ret_from_kernel_thread:
mov.l er2,er0
jsr @schedule_tail
mov.l @(LER4:16,sp),er0
mov.l @(LER5:16,sp),er1
jsr @er1
jmp @ret_from_exception
_resume:
/*
* Beware - when entering resume, offset of tss is in d1,
* prev (the current task) is in a0, next (the new task)
* is in a1 and d2.b is non-zero if the mm structure is
* shared between the tasks, so don't change these
* registers until their contents are no longer needed.
*/
/* save sr */
sub.w r3,r3
stc ccr,r3l
mov.w r3,@(THREAD_CCR+2:16,er0)
/* disable interrupts */
orc #0xc0,ccr
mov.l @_sw_usp,er3
mov.l er3,@(THREAD_USP:16,er0)
mov.l sp,@(THREAD_KSP:16,er0)
/* Skip address space switching if they are the same. */
/* FIXME: what did we hack out of here, this does nothing! */
mov.l @(THREAD_USP:16,er1),er0
mov.l er0,@_sw_usp
mov.l @(THREAD_KSP:16,er1),sp
/* restore status register */
mov.w @(THREAD_CCR+2:16,er1),r3
ldc r3l,ccr
rts
_trace_break:
subs #4,sp
SAVE_ALL
sub.l er1,er1
dec.l #1,er1
mov.l er1,@(LORIG,sp)
mov.l sp,er0
jsr @set_esp0
mov.l @_sw_usp,er0
mov.l @er0,er1
mov.w @(-2:16,er1),r2
cmp.w #0x5730,r2
beq 1f
subs #2,er1
mov.l er1,@er0
1:
and.w #0xff,e1
mov.l er1,er0
jsr @trace_trap
jmp @ret_from_exception
_nmi:
subs #4, sp
mov.l er0, @-sp
mov.l @_interrupt_redirect_table, er0
add.l #8*4, er0
mov.l er0, @(4,sp)
mov.l @sp+, er0
jmp @_interrupt_entry
#if defined(CONFIG_KGDB)
_kgdb_trap:
subs #4,sp
SAVE_ALL
mov.l sp,er0
add.l #LRET,er0
mov.l er0,@(LSP,sp)
jsr @set_esp0
mov.l sp,er0
subs #4,er0
jsr @h8300_kgdb_trap
jmp @ret_from_exception
#endif
.section .bss
_sw_ksp:
.space 4
_sw_usp:
.space 4
.end
