#include <linux/init.h>
#include <linux/linkage.h>

#include <asm/assembler.h>
#include <asm/asm-offsets.h>
#include <asm/errno.h>
#include <asm/thread_info.h>

@ Bad Abort numbers
@ -----------------
@
#define BAD_PREFETCH    0
#define BAD_DATA        1
#define BAD_ADDREXCPTN  2
#define BAD_IRQ         3
#define BAD_UNDEFINSTR  4

@
@ Most of the stack format comes from struct pt_regs, but with
@ the addition of 8 bytes for storing syscall args 5 and 6.
@ This _must_ remain a multiple of 8 for EABI.
@
#define S_OFF           8

/* 
 * The SWI code relies on the fact that R0 is at the bottom of the stack
 * (due to slow/fast restore user regs).
 */
#if S_R0 != 0
#error "Please fix"
#endif

        .macro  zero_fp
#ifdef CONFIG_FRAME_POINTER
        mov     fp, #0
#endif
        .endm

        .macro  alignment_trap, rtemp
#ifdef CONFIG_ALIGNMENT_TRAP
        ldr     \rtemp, .LCcralign
        ldr     \rtemp, [\rtemp]
        mcr     p15, 0, \rtemp, c1, c0
#endif
        .endm

        @
        @ Store/load the USER SP and LR registers by switching to the SYS
        @ mode. Useful in Thumb-2 mode where "stm/ldm rd, {sp, lr}^" is not
        @ available. Should only be called from SVC mode
        @
        .macro  store_user_sp_lr, rd, rtemp, offset = 0
        mrs     \rtemp, cpsr
        eor     \rtemp, \rtemp, #(SVC_MODE ^ SYSTEM_MODE)
        msr     cpsr_c, \rtemp                  @ switch to the SYS mode

        str     sp, [\rd, #\offset]             @ save sp_usr
        str     lr, [\rd, #\offset + 4]         @ save lr_usr

        eor     \rtemp, \rtemp, #(SVC_MODE ^ SYSTEM_MODE)
        msr     cpsr_c, \rtemp                  @ switch back to the SVC mode
        .endm

        .macro  load_user_sp_lr, rd, rtemp, offset = 0
        mrs     \rtemp, cpsr
        eor     \rtemp, \rtemp, #(SVC_MODE ^ SYSTEM_MODE)
        msr     cpsr_c, \rtemp                  @ switch to the SYS mode

        ldr     sp, [\rd, #\offset]             @ load sp_usr
        ldr     lr, [\rd, #\offset + 4]         @ load lr_usr

        eor     \rtemp, \rtemp, #(SVC_MODE ^ SYSTEM_MODE)
        msr     cpsr_c, \rtemp                  @ switch back to the SVC mode
        .endm

#ifndef CONFIG_THUMB2_KERNEL
        .macro  svc_exit, rpsr
        msr     spsr_cxsf, \rpsr
#if defined(CONFIG_CPU_V6)
        ldr     r0, [sp]
        strex   r1, r2, [sp]                    @ clear the exclusive monitor
        ldmib   sp, {r1 - pc}^                  @ load r1 - pc, cpsr
#elif defined(CONFIG_CPU_32v6K)
        clrex                                   @ clear the exclusive monitor
        ldmia   sp, {r0 - pc}^                  @ load r0 - pc, cpsr
#else
        ldmia   sp, {r0 - pc}^                  @ load r0 - pc, cpsr
#endif
        .endm

        .macro  restore_user_regs, fast = 0, offset = 0
        ldr     r1, [sp, #\offset + S_PSR]      @ get calling cpsr
        ldr     lr, [sp, #\offset + S_PC]!      @ get pc
        msr     spsr_cxsf, r1                   @ save in spsr_svc
#if defined(CONFIG_CPU_V6)
        strex   r1, r2, [sp]                    @ clear the exclusive monitor
#elif defined(CONFIG_CPU_32v6K)
        clrex                                   @ clear the exclusive monitor
#endif
        .if     \fast
        ldmdb   sp, {r1 - lr}^                  @ get calling r1 - lr
        .else
        ldmdb   sp, {r0 - lr}^                  @ get calling r0 - lr
        .endif
        mov     r0, r0                          @ ARMv5T and earlier require a nop
                                                @ after ldm {}^
        add     sp, sp, #S_FRAME_SIZE - S_PC
        movs    pc, lr                          @ return & move spsr_svc into cpsr
        .endm

        .macro  get_thread_info, rd
        mov     \rd, sp, lsr #13
        mov     \rd, \rd, lsl #13
        .endm

        @
        @ 32-bit wide "mov pc, reg"
        @
        .macro  movw_pc, reg
        mov     pc, \reg
        .endm
#else   /* CONFIG_THUMB2_KERNEL */
        .macro  svc_exit, rpsr
        ldr     lr, [sp, #S_SP]                 @ top of the stack
        ldrd    r0, r1, [sp, #S_LR]             @ calling lr and pc
        clrex                                   @ clear the exclusive monitor
        stmdb   lr!, {r0, r1, \rpsr}            @ calling lr and rfe context
        ldmia   sp, {r0 - r12}
        mov     sp, lr
        ldr     lr, [sp], #4
        rfeia   sp!
        .endm

        .macro  restore_user_regs, fast = 0, offset = 0
        clrex                                   @ clear the exclusive monitor
        mov     r2, sp
        load_user_sp_lr r2, r3, \offset + S_SP  @ calling sp, lr
        ldr     r1, [sp, #\offset + S_PSR]      @ get calling cpsr
        ldr     lr, [sp, #\offset + S_PC]       @ get pc
        add     sp, sp, #\offset + S_SP
        msr     spsr_cxsf, r1                   @ save in spsr_svc
        .if     \fast
        ldmdb   sp, {r1 - r12}                  @ get calling r1 - r12
        .else
        ldmdb   sp, {r0 - r12}                  @ get calling r0 - r12
        .endif
        add     sp, sp, #S_FRAME_SIZE - S_SP
        movs    pc, lr                          @ return & move spsr_svc into cpsr
        .endm

        .macro  get_thread_info, rd
        mov     \rd, sp
        lsr     \rd, \rd, #13
        mov     \rd, \rd, lsl #13
        .endm

        @
        @ 32-bit wide "mov pc, reg"
        @
        .macro  movw_pc, reg
        mov     pc, \reg
        nop
        .endm
#endif  /* !CONFIG_THUMB2_KERNEL */

/*
 * These are the registers used in the syscall handler, and allow us to
 * have in theory up to 7 arguments to a function - r0 to r6.
 *
 * r7 is reserved for the system call number for thumb mode.
 *
 * Note that tbl == why is intentional.
 *
 * We must set at least "tsk" and "why" when calling ret_with_reschedule.
 */
scno    .req    r7              @ syscall number
tbl     .req    r8              @ syscall table pointer
why     .req    r8              @ Linux syscall (!= 0)
tsk     .req    r9              @ current thread_info