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linux/arch/microblaze/kernel/entry.S
Michal Simek 841d6e8c4e microblaze: entry.S use delay slot for return handlers 
Signed-off-by: Michal Simek <monstr@monstr.eu>
2010-03-11 14:26:13 +01:00

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/*
* Low-level system-call handling, trap handlers and context-switching
*
* Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
* Copyright (C) 2008-2009 PetaLogix
* Copyright (C) 2003 John Williams <jwilliams@itee.uq.edu.au>
* Copyright (C) 2001,2002 NEC Corporation
* Copyright (C) 2001,2002 Miles Bader <miles@gnu.org>
*
* 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.
*
* Written by Miles Bader <miles@gnu.org>
* Heavily modified by John Williams for Microblaze
*/
#include <linux/sys.h>
#include <linux/linkage.h>
#include <asm/entry.h>
#include <asm/current.h>
#include <asm/processor.h>
#include <asm/exceptions.h>
#include <asm/asm-offsets.h>
#include <asm/thread_info.h>
#include <asm/page.h>
#include <asm/unistd.h>
#include <linux/errno.h>
#include <asm/signal.h>
#undef DEBUG
/* The size of a state save frame. */
#define STATE_SAVE_SIZE (PT_SIZE + STATE_SAVE_ARG_SPACE)
/* The offset of the struct pt_regs in a `state save frame' on the stack. */
#define PTO STATE_SAVE_ARG_SPACE /* 24 the space for args */
#define C_ENTRY(name) .globl name; .align 4; name
/*
* Various ways of setting and clearing BIP in flags reg.
* This is mucky, but necessary using microblaze version that
* allows msr ops to write to BIP
*/
#if CONFIG_XILINX_MICROBLAZE0_USE_MSR_INSTR
.macro clear_bip
msrclr r11, MSR_BIP
nop
.endm
.macro set_bip
msrset r11, MSR_BIP
nop
.endm
.macro clear_eip
msrclr r11, MSR_EIP
nop
.endm
.macro set_ee
msrset r11, MSR_EE
nop
.endm
.macro disable_irq
msrclr r11, MSR_IE
nop
.endm
.macro enable_irq
msrset r11, MSR_IE
nop
.endm
.macro set_ums
msrset r11, MSR_UMS
nop
msrclr r11, MSR_VMS
nop
.endm
.macro set_vms
msrclr r11, MSR_UMS
nop
msrset r11, MSR_VMS
nop
.endm
.macro clear_vms_ums
msrclr r11, MSR_VMS
nop
msrclr r11, MSR_UMS
nop
.endm
#else
.macro clear_bip
mfs r11, rmsr
nop
andi r11, r11, ~MSR_BIP
mts rmsr, r11
nop
.endm
.macro set_bip
mfs r11, rmsr
nop
ori r11, r11, MSR_BIP
mts rmsr, r11
nop
.endm
.macro clear_eip
mfs r11, rmsr
nop
andi r11, r11, ~MSR_EIP
mts rmsr, r11
nop
.endm
.macro set_ee
mfs r11, rmsr
nop
ori r11, r11, MSR_EE
mts rmsr, r11
nop
.endm
.macro disable_irq
mfs r11, rmsr
nop
andi r11, r11, ~MSR_IE
mts rmsr, r11
nop
.endm
.macro enable_irq
mfs r11, rmsr
nop
ori r11, r11, MSR_IE
mts rmsr, r11
nop
.endm
.macro set_ums
mfs r11, rmsr
nop
ori r11, r11, MSR_VMS
andni r11, r11, MSR_UMS
mts rmsr, r11
nop
.endm
.macro set_vms
mfs r11, rmsr
nop
ori r11, r11, MSR_VMS
andni r11, r11, MSR_UMS
mts rmsr, r11
nop
.endm
.macro clear_vms_ums
mfs r11, rmsr
nop
andni r11, r11, (MSR_VMS|MSR_UMS)
mts rmsr,r11
nop
.endm
#endif
/* Define how to call high-level functions. With MMU, virtual mode must be
* enabled when calling the high-level function. Clobbers R11.
* VM_ON, VM_OFF, DO_JUMP_BIPCLR, DO_CALL
*/
/* turn on virtual protected mode save */
#define VM_ON \
set_ums; \
rted r0, 2f; \
2: nop;
/* turn off virtual protected mode save and user mode save*/
#define VM_OFF \
clear_vms_ums; \
rted r0, TOPHYS(1f); \
1: nop;
#define SAVE_REGS \
swi r2, r1, PTO+PT_R2; /* Save SDA */ \
swi r5, r1, PTO+PT_R5; \
swi r6, r1, PTO+PT_R6; \
swi r7, r1, PTO+PT_R7; \
swi r8, r1, PTO+PT_R8; \
swi r9, r1, PTO+PT_R9; \
swi r10, r1, PTO+PT_R10; \
swi r11, r1, PTO+PT_R11; /* save clobbered regs after rval */\
swi r12, r1, PTO+PT_R12; \
swi r13, r1, PTO+PT_R13; /* Save SDA2 */ \
swi r14, r1, PTO+PT_PC; /* PC, before IRQ/trap */ \
swi r15, r1, PTO+PT_R15; /* Save LP */ \
swi r18, r1, PTO+PT_R18; /* Save asm scratch reg */ \
swi r19, r1, PTO+PT_R19; \
swi r20, r1, PTO+PT_R20; \
swi r21, r1, PTO+PT_R21; \
swi r22, r1, PTO+PT_R22; \
swi r23, r1, PTO+PT_R23; \
swi r24, r1, PTO+PT_R24; \
swi r25, r1, PTO+PT_R25; \
swi r26, r1, PTO+PT_R26; \
swi r27, r1, PTO+PT_R27; \
swi r28, r1, PTO+PT_R28; \
swi r29, r1, PTO+PT_R29; \
swi r30, r1, PTO+PT_R30; \
swi r31, r1, PTO+PT_R31; /* Save current task reg */ \
mfs r11, rmsr; /* save MSR */ \
nop; \
swi r11, r1, PTO+PT_MSR;
#define RESTORE_REGS \
lwi r11, r1, PTO+PT_MSR; \
mts rmsr , r11; \
nop; \
lwi r2, r1, PTO+PT_R2; /* restore SDA */ \
lwi r5, r1, PTO+PT_R5; \
lwi r6, r1, PTO+PT_R6; \
lwi r7, r1, PTO+PT_R7; \
lwi r8, r1, PTO+PT_R8; \
lwi r9, r1, PTO+PT_R9; \
lwi r10, r1, PTO+PT_R10; \
lwi r11, r1, PTO+PT_R11; /* restore clobbered regs after rval */\
lwi r12, r1, PTO+PT_R12; \
lwi r13, r1, PTO+PT_R13; /* restore SDA2 */ \
lwi r14, r1, PTO+PT_PC; /* RESTORE_LINK PC, before IRQ/trap */\
lwi r15, r1, PTO+PT_R15; /* restore LP */ \
lwi r18, r1, PTO+PT_R18; /* restore asm scratch reg */ \
lwi r19, r1, PTO+PT_R19; \
lwi r20, r1, PTO+PT_R20; \
lwi r21, r1, PTO+PT_R21; \
lwi r22, r1, PTO+PT_R22; \
lwi r23, r1, PTO+PT_R23; \
lwi r24, r1, PTO+PT_R24; \
lwi r25, r1, PTO+PT_R25; \
lwi r26, r1, PTO+PT_R26; \
lwi r27, r1, PTO+PT_R27; \
lwi r28, r1, PTO+PT_R28; \
lwi r29, r1, PTO+PT_R29; \
lwi r30, r1, PTO+PT_R30; \
lwi r31, r1, PTO+PT_R31; /* Restore cur task reg */
.text
/*
* User trap.
*
* System calls are handled here.
*
* Syscall protocol:
* Syscall number in r12, args in r5-r10
* Return value in r3
*
* Trap entered via brki instruction, so BIP bit is set, and interrupts
* are masked. This is nice, means we don't have to CLI before state save
*/
C_ENTRY(_user_exception):
swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)) /* save stack */
addi r14, r14, 4 /* return address is 4 byte after call */
swi r11, r0, TOPHYS(r0_ram + PTO + PT_R11); /* Save r11 */
lwi r11, r0, TOPHYS(PER_CPU(KM));/* See if already in kernel mode.*/
beqi r11, 1f; /* Jump ahead if coming from user */
/* Kernel-mode state save. */
lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP)); /* Reload kernel stack-ptr*/
tophys(r1,r11);
swi r11, r1, (PT_R1-PT_SIZE); /* Save original SP. */
lwi r11, r0, TOPHYS(r0_ram + PTO + PT_R11); /* restore r11 */
addik r1, r1, -STATE_SAVE_SIZE; /* Make room on the stack. */
SAVE_REGS
addi r11, r0, 1; /* Was in kernel-mode. */
swi r11, r1, PTO+PT_MODE; /* pt_regs -> kernel mode */
brid 2f;
nop; /* Fill delay slot */
/* User-mode state save. */
1:
lwi r11, r0, TOPHYS(r0_ram + PTO + PT_R11); /* restore r11 */
lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); /* get saved current */
tophys(r1,r1);
lwi r1, r1, TS_THREAD_INFO; /* get stack from task_struct */
/* calculate kernel stack pointer from task struct 8k */
addik r1, r1, THREAD_SIZE;
tophys(r1,r1);
addik r1, r1, -STATE_SAVE_SIZE; /* Make room on the stack. */
SAVE_REGS
swi r0, r1, PTO+PT_MODE; /* Was in user-mode. */
lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
swi r11, r1, PTO+PT_R1; /* Store user SP. */
addi r11, r0, 1;
swi r11, r0, TOPHYS(PER_CPU(KM)); /* Now we're in kernel-mode. */
2: lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
/* Save away the syscall number. */
swi r12, r1, PTO+PT_R0;
tovirt(r1,r1)
/* where the trap should return need -8 to adjust for rtsd r15, 8*/
/* Jump to the appropriate function for the system call number in r12
* (r12 is not preserved), or return an error if r12 is not valid. The LP
* register should point to the location where
* the called function should return. [note that MAKE_SYS_CALL uses label 1] */
# Step into virtual mode.
set_vms;
addik r11, r0, 3f
rtid r11, 0
nop
3:
lwi r11, CURRENT_TASK, TS_THREAD_INFO /* get thread info */
lwi r11, r11, TI_FLAGS /* get flags in thread info */
andi r11, r11, _TIF_WORK_SYSCALL_MASK
beqi r11, 4f
addik r3, r0, -ENOSYS
swi r3, r1, PTO + PT_R3
brlid r15, do_syscall_trace_enter
addik r5, r1, PTO + PT_R0
# do_syscall_trace_enter returns the new syscall nr.
addk r12, r0, r3
lwi r5, r1, PTO+PT_R5;
lwi r6, r1, PTO+PT_R6;
lwi r7, r1, PTO+PT_R7;
lwi r8, r1, PTO+PT_R8;
lwi r9, r1, PTO+PT_R9;
lwi r10, r1, PTO+PT_R10;
4:
/* Jump to the appropriate function for the system call number in r12
* (r12 is not preserved), or return an error if r12 is not valid.
* The LP register should point to the location where the called function
* should return. [note that MAKE_SYS_CALL uses label 1] */
/* See if the system call number is valid */
addi r11, r12, -__NR_syscalls;
bgei r11,5f;
/* Figure out which function to use for this system call. */
/* Note Microblaze barrel shift is optional, so don't rely on it */
add r12, r12, r12; /* convert num -> ptr */
add r12, r12, r12;
#ifdef DEBUG
/* Trac syscalls and stored them to r0_ram */
lwi r3, r12, 0x400 + r0_ram
addi r3, r3, 1
swi r3, r12, 0x400 + r0_ram
#endif
# Find and jump into the syscall handler.
lwi r12, r12, sys_call_table
/* where the trap should return need -8 to adjust for rtsd r15, 8 */
la r15, r0, ret_from_trap-8
bra r12
/* The syscall number is invalid, return an error. */
5:
addi r3, r0, -ENOSYS;
rtsd r15,8; /* looks like a normal subroutine return */
or r0, r0, r0
/* Entry point used to return from a syscall/trap */
/* We re-enable BIP bit before state restore */
C_ENTRY(ret_from_trap):
set_bip; /* Ints masked for state restore*/
lwi r11, r1, PTO+PT_MODE;
/* See if returning to kernel mode, if so, skip resched &c. */
bnei r11, 2f;
swi r3, r1, PTO + PT_R3
swi r4, r1, PTO + PT_R4
/* We're returning to user mode, so check for various conditions that
* trigger rescheduling. */
/* FIXME: Restructure all these flag checks. */
lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
lwi r11, r11, TI_FLAGS; /* get flags in thread info */
andi r11, r11, _TIF_WORK_SYSCALL_MASK
beqi r11, 1f
brlid r15, do_syscall_trace_leave
addik r5, r1, PTO + PT_R0
1:
/* We're returning to user mode, so check for various conditions that
* trigger rescheduling. */
/* get thread info from current task */
lwi r11, CURRENT_TASK, TS_THREAD_INFO;
lwi r11, r11, TI_FLAGS; /* get flags in thread info */
andi r11, r11, _TIF_NEED_RESCHED;
beqi r11, 5f;
bralid r15, schedule; /* Call scheduler */
nop; /* delay slot */
/* Maybe handle a signal */
5: /* get thread info from current task*/
lwi r11, CURRENT_TASK, TS_THREAD_INFO;
lwi r11, r11, TI_FLAGS; /* get flags in thread info */
andi r11, r11, _TIF_SIGPENDING;
beqi r11, 1f; /* Signals to handle, handle them */
la r5, r1, PTO; /* Arg 1: struct pt_regs *regs */
addi r7, r0, 1; /* Arg 3: int in_syscall */
bralid r15, do_signal; /* Handle any signals */
add r6, r0, r0; /* Arg 2: sigset_t *oldset */
/* Finally, return to user state. */
1:
lwi r3, r1, PTO + PT_R3; /* restore syscall result */
lwi r4, r1, PTO + PT_R4;
swi r0, r0, PER_CPU(KM); /* Now officially in user state. */
swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */
VM_OFF;
tophys(r1,r1);
RESTORE_REGS;
addik r1, r1, STATE_SAVE_SIZE /* Clean up stack space. */
lwi r1, r1, PT_R1 - PT_SIZE;/* Restore user stack pointer. */
bri 6f;
/* Return to kernel state. */
2: VM_OFF;
tophys(r1,r1);
RESTORE_REGS;
addik r1, r1, STATE_SAVE_SIZE /* Clean up stack space. */
tovirt(r1,r1);
6:
TRAP_return: /* Make global symbol for debugging */
rtbd r14, 0; /* Instructions to return from an IRQ */
nop;
/* These syscalls need access to the struct pt_regs on the stack, so we
implement them in assembly (they're basically all wrappers anyway). */
C_ENTRY(sys_fork_wrapper):
addi r5, r0, SIGCHLD /* Arg 0: flags */
lwi r6, r1, PTO+PT_R1 /* Arg 1: child SP (use parent's) */
la r7, r1, PTO /* Arg 2: parent context */
add r8. r0, r0 /* Arg 3: (unused) */
add r9, r0, r0; /* Arg 4: (unused) */
add r10, r0, r0; /* Arg 5: (unused) */
brid do_fork /* Do real work (tail-call) */
nop;
/* This the initial entry point for a new child thread, with an appropriate
stack in place that makes it look the the child is in the middle of an
syscall. This function is actually `returned to' from switch_thread
(copy_thread makes ret_from_fork the return address in each new thread's
saved context). */
C_ENTRY(ret_from_fork):
bralid r15, schedule_tail; /* ...which is schedule_tail's arg */
add r3, r5, r0; /* switch_thread returns the prev task */
/* ( in the delay slot ) */
add r3, r0, r0; /* Child's fork call should return 0. */
brid ret_from_trap; /* Do normal trap return */
nop;
C_ENTRY(sys_vfork):
brid microblaze_vfork /* Do real work (tail-call) */
la r5, r1, PTO
C_ENTRY(sys_clone):
bnei r6, 1f; /* See if child SP arg (arg 1) is 0. */
lwi r6, r1, PTO+PT_R1; /* If so, use paret's stack ptr */
1: la r7, r1, PTO; /* Arg 2: parent context */
add r8, r0, r0; /* Arg 3: (unused) */
add r9, r0, r0; /* Arg 4: (unused) */
add r10, r0, r0; /* Arg 5: (unused) */
brid do_fork /* Do real work (tail-call) */
nop;
C_ENTRY(sys_execve):
la r8, r1, PTO; /* add user context as 4th arg */
brid microblaze_execve; /* Do real work (tail-call).*/
nop;
C_ENTRY(sys_rt_sigreturn_wrapper):
swi r3, r1, PTO+PT_R3; /* restore saved r3, r4 registers */
swi r4, r1, PTO+PT_R4;
la r5, r1, PTO; /* add user context as 1st arg */
brlid r15, sys_rt_sigreturn /* Do real work */
nop;
lwi r3, r1, PTO+PT_R3; /* restore saved r3, r4 registers */
lwi r4, r1, PTO+PT_R4;
bri ret_from_trap /* fall through will not work here due to align */
nop;
/*
* HW EXCEPTION rutine start
*/
#define SAVE_STATE \
swi r11, r0, TOPHYS(r0_ram + PTO + PT_R11); /* Save r11 */ \
set_bip; /*equalize initial state for all possible entries*/\
clear_eip; \
enable_irq; \
set_ee; \
/* See if already in kernel mode.*/ \
lwi r11, r0, TOPHYS(PER_CPU(KM)); \
beqi r11, 1f; /* Jump ahead if coming from user */\
/* Kernel-mode state save. */ \
/* Reload kernel stack-ptr. */ \
lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP)); \
tophys(r1,r11); \
swi r11, r1, (PT_R1-PT_SIZE); /* Save original SP. */ \
lwi r11, r0, TOPHYS(r0_ram + PTO + PT_R11); /* restore r11 */\
addik r1, r1, -STATE_SAVE_SIZE; /* Make room on the stack. */\
/* store return registers separately because \
* this macros is use for others exceptions */ \
swi r3, r1, PTO + PT_R3; \
swi r4, r1, PTO + PT_R4; \
SAVE_REGS \
/* PC, before IRQ/trap - this is one instruction above */ \
swi r17, r1, PTO+PT_PC; \
\
addi r11, r0, 1; /* Was in kernel-mode. */ \
swi r11, r1, PTO+PT_MODE; \
brid 2f; \
nop; /* Fill delay slot */ \
1: /* User-mode state save. */ \
lwi r11, r0, TOPHYS(r0_ram + PTO + PT_R11); /* restore r11 */\
lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); /* get saved current */\
tophys(r1,r1); \
lwi r1, r1, TS_THREAD_INFO; /* get the thread info */ \
addik r1, r1, THREAD_SIZE; /* calculate kernel stack pointer */\
tophys(r1,r1); \
\
addik r1, r1, -STATE_SAVE_SIZE; /* Make room on the stack. */\
/* store return registers separately because this macros \
* is use for others exceptions */ \
swi r3, r1, PTO + PT_R3; \
swi r4, r1, PTO + PT_R4; \
SAVE_REGS \
/* PC, before IRQ/trap - this is one instruction above FIXME*/ \
swi r17, r1, PTO+PT_PC; \
\
swi r0, r1, PTO+PT_MODE; /* Was in user-mode. */ \
lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP)); \
swi r11, r1, PTO+PT_R1; /* Store user SP. */ \
addi r11, r0, 1; \
swi r11, r0, TOPHYS(PER_CPU(KM)); /* Now we're in kernel-mode.*/\
2: lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); \
/* Save away the syscall number. */ \
swi r0, r1, PTO+PT_R0; \
tovirt(r1,r1)
C_ENTRY(full_exception_trap):
swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)) /* save stack */
/* adjust exception address for privileged instruction
* for finding where is it */
addik r17, r17, -4
SAVE_STATE /* Save registers */
/* FIXME this can be store directly in PT_ESR reg.
* I tested it but there is a fault */
/* where the trap should return need -8 to adjust for rtsd r15, 8 */
la r15, r0, ret_from_exc - 8
la r5, r1, PTO /* parameter struct pt_regs * regs */
mfs r6, resr
nop
mfs r7, rfsr; /* save FSR */
nop
mts rfsr, r0; /* Clear sticky fsr */
nop
la r12, r0, full_exception
set_vms;
rtbd r12, 0;
nop;
/*
* Unaligned data trap.
*
* Unaligned data trap last on 4k page is handled here.
*
* Trap entered via exception, so EE bit is set, and interrupts
* are masked. This is nice, means we don't have to CLI before state save
*
* The assembler routine is in "arch/microblaze/kernel/hw_exception_handler.S"
*/
C_ENTRY(unaligned_data_trap):
swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)) /* save stack */
SAVE_STATE /* Save registers.*/
/* where the trap should return need -8 to adjust for rtsd r15, 8 */
la r15, r0, ret_from_exc-8
mfs r3, resr /* ESR */
nop
mfs r4, rear /* EAR */
nop
la r7, r1, PTO /* parameter struct pt_regs * regs */
la r12, r0, _unaligned_data_exception
set_vms;
rtbd r12, 0; /* interrupts enabled */
nop;
/*
* Page fault traps.
*
* If the real exception handler (from hw_exception_handler.S) didn't find
* the mapping for the process, then we're thrown here to handle such situation.
*
* Trap entered via exceptions, so EE bit is set, and interrupts
* are masked. This is nice, means we don't have to CLI before state save
*
* Build a standard exception frame for TLB Access errors. All TLB exceptions
* will bail out to this point if they can't resolve the lightweight TLB fault.
*
* The C function called is in "arch/microblaze/mm/fault.c", declared as:
* void do_page_fault(struct pt_regs *regs,
* unsigned long address,
* unsigned long error_code)
*/
/* data and intruction trap - which is choose is resolved int fault.c */
C_ENTRY(page_fault_data_trap):
swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)) /* save stack */
SAVE_STATE /* Save registers.*/
/* where the trap should return need -8 to adjust for rtsd r15, 8 */
la r15, r0, ret_from_exc-8
la r5, r1, PTO /* parameter struct pt_regs * regs */
mfs r6, rear /* parameter unsigned long address */
nop
mfs r7, resr /* parameter unsigned long error_code */
nop
la r12, r0, do_page_fault
set_vms;
rtbd r12, 0; /* interrupts enabled */
nop;
C_ENTRY(page_fault_instr_trap):
swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)) /* save stack */
SAVE_STATE /* Save registers.*/
/* where the trap should return need -8 to adjust for rtsd r15, 8 */
la r15, r0, ret_from_exc-8
la r5, r1, PTO /* parameter struct pt_regs * regs */
mfs r6, rear /* parameter unsigned long address */
nop
ori r7, r0, 0 /* parameter unsigned long error_code */
la r12, r0, do_page_fault
set_vms;
rtbd r12, 0; /* interrupts enabled */
nop;
/* Entry point used to return from an exception. */
C_ENTRY(ret_from_exc):
set_bip; /* Ints masked for state restore*/
lwi r11, r1, PTO+PT_MODE;
bnei r11, 2f; /* See if returning to kernel mode, */
/* ... if so, skip resched &c. */
/* We're returning to user mode, so check for various conditions that
trigger rescheduling. */
lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
lwi r11, r11, TI_FLAGS; /* get flags in thread info */
andi r11, r11, _TIF_NEED_RESCHED;
beqi r11, 5f;
/* Call the scheduler before returning from a syscall/trap. */
bralid r15, schedule; /* Call scheduler */
nop; /* delay slot */
/* Maybe handle a signal */
5: lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
lwi r11, r11, TI_FLAGS; /* get flags in thread info */
andi r11, r11, _TIF_SIGPENDING;
beqi r11, 1f; /* Signals to handle, handle them */
/*
* Handle a signal return; Pending signals should be in r18.
*
* Not all registers are saved by the normal trap/interrupt entry
* points (for instance, call-saved registers (because the normal
* C-compiler calling sequence in the kernel makes sure they're
* preserved), and call-clobbered registers in the case of
* traps), but signal handlers may want to examine or change the
* complete register state. Here we save anything not saved by
* the normal entry sequence, so that it may be safely restored
* (in a possibly modified form) after do_signal returns.
* store return registers separately because this macros is use
* for others exceptions */
la r5, r1, PTO; /* Arg 1: struct pt_regs *regs */
addi r7, r0, 0; /* Arg 3: int in_syscall */
bralid r15, do_signal; /* Handle any signals */
add r6, r0, r0; /* Arg 2: sigset_t *oldset */
/* Finally, return to user state. */
1: swi r0, r0, PER_CPU(KM); /* Now officially in user state. */
swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */
VM_OFF;
tophys(r1,r1);
lwi r3, r1, PTO+PT_R3; /* restore saved r3, r4 registers */
lwi r4, r1, PTO+PT_R4;
RESTORE_REGS;
addik r1, r1, STATE_SAVE_SIZE /* Clean up stack space. */
lwi r1, r1, PT_R1 - PT_SIZE; /* Restore user stack pointer. */
bri 6f;
/* Return to kernel state. */
2: VM_OFF;
tophys(r1,r1);
lwi r3, r1, PTO+PT_R3; /* restore saved r3, r4 registers */
lwi r4, r1, PTO+PT_R4;
RESTORE_REGS;
addik r1, r1, STATE_SAVE_SIZE /* Clean up stack space. */
tovirt(r1,r1);
6:
EXC_return: /* Make global symbol for debugging */
rtbd r14, 0; /* Instructions to return from an IRQ */
nop;
/*
* HW EXCEPTION rutine end
*/
/*
* Hardware maskable interrupts.
*
* The stack-pointer (r1) should have already been saved to the memory
* location PER_CPU(ENTRY_SP).
*/
C_ENTRY(_interrupt):
/* MS: we are in physical address */
/* Save registers, switch to proper stack, convert SP to virtual.*/
swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP))
swi r11, r0, TOPHYS(PER_CPU(R11_SAVE));
/* MS: See if already in kernel mode. */
lwi r11, r0, TOPHYS(PER_CPU(KM));
beqi r11, 1f; /* MS: Jump ahead if coming from user */
/* Kernel-mode state save. */
or r11, r1, r0
tophys(r1,r11); /* MS: I have in r1 physical address where stack is */
/* MS: Save original SP - position PT_R1 to next stack frame 4 *1 - 152*/
swi r11, r1, (PT_R1 - PT_SIZE);
/* MS: restore r11 because of saving in SAVE_REGS */
lwi r11, r0, TOPHYS(PER_CPU(R11_SAVE));
/* save registers */
/* MS: Make room on the stack -> activation record */
addik r1, r1, -STATE_SAVE_SIZE;
/* MS: store return registers separately because
* this macros is use for others exceptions */
swi r3, r1, PTO + PT_R3;
swi r4, r1, PTO + PT_R4;
SAVE_REGS
/* MS: store mode */
addi r11, r0, 1; /* MS: Was in kernel-mode. */
swi r11, r1, PTO + PT_MODE; /* MS: and save it */
brid 2f;
nop; /* MS: Fill delay slot */
1:
/* User-mode state save. */
/* MS: restore r11 -> FIXME move before SAVE_REG */
lwi r11, r0, TOPHYS(PER_CPU(R11_SAVE));
/* MS: get the saved current */
lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
tophys(r1,r1);
lwi r1, r1, TS_THREAD_INFO;
addik r1, r1, THREAD_SIZE;
tophys(r1,r1);
/* save registers */
addik r1, r1, -STATE_SAVE_SIZE;
swi r3, r1, PTO+PT_R3;
swi r4, r1, PTO+PT_R4;
SAVE_REGS
/* calculate mode */
swi r0, r1, PTO + PT_MODE;
lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
swi r11, r1, PTO+PT_R1;
/* setup kernel mode to KM */
addi r11, r0, 1;
swi r11, r0, TOPHYS(PER_CPU(KM));
2:
lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
swi r0, r1, PTO + PT_R0;
tovirt(r1,r1)
la r5, r1, PTO;
set_vms;
la r11, r0, do_IRQ;
la r15, r0, irq_call;
irq_call:rtbd r11, 0;
nop;
/* MS: we are in virtual mode */
ret_from_irq:
lwi r11, r1, PTO + PT_MODE;
bnei r11, 2f;
lwi r11, CURRENT_TASK, TS_THREAD_INFO;
lwi r11, r11, TI_FLAGS; /* MS: get flags from thread info */
andi r11, r11, _TIF_NEED_RESCHED;
beqi r11, 5f
bralid r15, schedule;
nop; /* delay slot */
/* Maybe handle a signal */
5: lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* MS: get thread info */
lwi r11, r11, TI_FLAGS; /* get flags in thread info */
andi r11, r11, _TIF_SIGPENDING;
beqid r11, no_intr_resched
/* Handle a signal return; Pending signals should be in r18. */
addi r7, r0, 0; /* Arg 3: int in_syscall */
la r5, r1, PTO; /* Arg 1: struct pt_regs *regs */
bralid r15, do_signal; /* Handle any signals */
add r6, r0, r0; /* Arg 2: sigset_t *oldset */
/* Finally, return to user state. */
no_intr_resched:
/* Disable interrupts, we are now committed to the state restore */
disable_irq
swi r0, r0, PER_CPU(KM); /* MS: Now officially in user state. */
swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE);
VM_OFF;
tophys(r1,r1);
lwi r3, r1, PTO + PT_R3; /* MS: restore saved r3, r4 registers */
lwi r4, r1, PTO + PT_R4;
RESTORE_REGS
addik r1, r1, STATE_SAVE_SIZE /* MS: Clean up stack space. */
lwi r1, r1, PT_R1 - PT_SIZE;
bri 6f;
/* MS: Return to kernel state. */
2:
#ifdef CONFIG_PREEMPT
lwi r11, CURRENT_TASK, TS_THREAD_INFO;
/* MS: get preempt_count from thread info */
lwi r5, r11, TI_PREEMPT_COUNT;
bgti r5, restore;
lwi r5, r11, TI_FLAGS; /* get flags in thread info */
andi r5, r5, _TIF_NEED_RESCHED;
beqi r5, restore /* if zero jump over */
preempt:
/* interrupts are off that's why I am calling preempt_chedule_irq */
bralid r15, preempt_schedule_irq
nop
lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
lwi r5, r11, TI_FLAGS; /* get flags in thread info */
andi r5, r5, _TIF_NEED_RESCHED;
bnei r5, preempt /* if non zero jump to resched */
restore:
#endif
VM_OFF /* MS: turn off MMU */
tophys(r1,r1)
lwi r3, r1, PTO + PT_R3; /* MS: restore saved r3, r4 registers */
lwi r4, r1, PTO + PT_R4;
RESTORE_REGS
addik r1, r1, STATE_SAVE_SIZE /* MS: Clean up stack space. */
tovirt(r1,r1);
6:
IRQ_return: /* MS: Make global symbol for debugging */
rtid r14, 0
nop
/*
* `Debug' trap
* We enter dbtrap in "BIP" (breakpoint) mode.
* So we exit the breakpoint mode with an 'rtbd' and proceed with the
* original dbtrap.
* however, wait to save state first
*/
C_ENTRY(_debug_exception):
/* BIP bit is set on entry, no interrupts can occur */
swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP))
swi r11, r0, TOPHYS(r0_ram + PTO + PT_R11); /* Save r11 */
set_bip; /*equalize initial state for all possible entries*/
clear_eip;
enable_irq;
lwi r11, r0, TOPHYS(PER_CPU(KM));/* See if already in kernel mode.*/
beqi r11, 1f; /* Jump ahead if coming from user */
/* Kernel-mode state save. */
lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP)); /* Reload kernel stack-ptr*/
tophys(r1,r11);
swi r11, r1, (PT_R1-PT_SIZE); /* Save original SP. */
lwi r11, r0, TOPHYS(r0_ram + PTO + PT_R11); /* restore r11 */
addik r1, r1, -STATE_SAVE_SIZE; /* Make room on the stack. */
swi r3, r1, PTO + PT_R3;
swi r4, r1, PTO + PT_R4;
SAVE_REGS;
addi r11, r0, 1; /* Was in kernel-mode. */
swi r11, r1, PTO + PT_MODE;
brid 2f;
nop; /* Fill delay slot */
1: /* User-mode state save. */
lwi r11, r0, TOPHYS(r0_ram + PTO + PT_R11); /* restore r11 */
lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); /* get saved current */
tophys(r1,r1);
lwi r1, r1, TS_THREAD_INFO; /* get the thread info */
addik r1, r1, THREAD_SIZE; /* calculate kernel stack pointer */
tophys(r1,r1);
addik r1, r1, -STATE_SAVE_SIZE; /* Make room on the stack. */
swi r3, r1, PTO + PT_R3;
swi r4, r1, PTO + PT_R4;
SAVE_REGS;
swi r0, r1, PTO+PT_MODE; /* Was in user-mode. */
lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
swi r11, r1, PTO+PT_R1; /* Store user SP. */
addi r11, r0, 1;
swi r11, r0, TOPHYS(PER_CPU(KM)); /* Now we're in kernel-mode. */
2: lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
/* Save away the syscall number. */
swi r0, r1, PTO+PT_R0;
tovirt(r1,r1)
addi r5, r0, SIGTRAP /* send the trap signal */
add r6, r0, CURRENT_TASK; /* Get current task ptr into r11 */
addk r7, r0, r0 /* 3rd param zero */
set_vms;
la r11, r0, send_sig;
la r15, r0, dbtrap_call;
dbtrap_call: rtbd r11, 0;
nop;
set_bip; /* Ints masked for state restore*/
lwi r11, r1, PTO+PT_MODE;
bnei r11, 2f;
/* Get current task ptr into r11 */
lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
lwi r11, r11, TI_FLAGS; /* get flags in thread info */
andi r11, r11, _TIF_NEED_RESCHED;
beqi r11, 5f;
/* Call the scheduler before returning from a syscall/trap. */
bralid r15, schedule; /* Call scheduler */
nop; /* delay slot */
/* XXX Is PT_DTRACE handling needed here? */
/* XXX m68knommu also checks TASK_STATE & TASK_COUNTER here. */
/* Maybe handle a signal */
5: lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
lwi r11, r11, TI_FLAGS; /* get flags in thread info */
andi r11, r11, _TIF_SIGPENDING;
beqi r11, 1f; /* Signals to handle, handle them */
/* Handle a signal return; Pending signals should be in r18. */
/* Not all registers are saved by the normal trap/interrupt entry
points (for instance, call-saved registers (because the normal
C-compiler calling sequence in the kernel makes sure they're
preserved), and call-clobbered registers in the case of
traps), but signal handlers may want to examine or change the
complete register state. Here we save anything not saved by
the normal entry sequence, so that it may be safely restored
(in a possibly modified form) after do_signal returns. */
la r5, r1, PTO; /* Arg 1: struct pt_regs *regs */
addi r7, r0, 0; /* Arg 3: int in_syscall */
bralid r15, do_signal; /* Handle any signals */
add r6, r0, r0; /* Arg 2: sigset_t *oldset */
/* Finally, return to user state. */
1: swi r0, r0, PER_CPU(KM); /* Now officially in user state. */
swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */
VM_OFF;
tophys(r1,r1);
lwi r3, r1, PTO+PT_R3; /* restore saved r3, r4 registers */
lwi r4, r1, PTO+PT_R4;
RESTORE_REGS
addik r1, r1, STATE_SAVE_SIZE /* Clean up stack space. */
lwi r1, r1, PT_R1 - PT_SIZE;
/* Restore user stack pointer. */
bri 6f;
/* Return to kernel state. */
2: VM_OFF;
tophys(r1,r1);
lwi r3, r1, PTO+PT_R3; /* restore saved r3, r4 registers */
lwi r4, r1, PTO+PT_R4;
RESTORE_REGS
addik r1, r1, STATE_SAVE_SIZE /* Clean up stack space. */
tovirt(r1,r1);
6:
DBTRAP_return: /* Make global symbol for debugging */
rtbd r14, 0; /* Instructions to return from an IRQ */
nop;
ENTRY(_switch_to)
/* prepare return value */
addk r3, r0, CURRENT_TASK
/* save registers in cpu_context */
/* use r11 and r12, volatile registers, as temp register */
/* give start of cpu_context for previous process */
addik r11, r5, TI_CPU_CONTEXT
swi r1, r11, CC_R1
swi r2, r11, CC_R2
/* skip volatile registers.
* they are saved on stack when we jumped to _switch_to() */
/* dedicated registers */
swi r13, r11, CC_R13
swi r14, r11, CC_R14
swi r15, r11, CC_R15
swi r16, r11, CC_R16
swi r17, r11, CC_R17
swi r18, r11, CC_R18
/* save non-volatile registers */
swi r19, r11, CC_R19
swi r20, r11, CC_R20
swi r21, r11, CC_R21
swi r22, r11, CC_R22
swi r23, r11, CC_R23
swi r24, r11, CC_R24
swi r25, r11, CC_R25
swi r26, r11, CC_R26
swi r27, r11, CC_R27
swi r28, r11, CC_R28
swi r29, r11, CC_R29
swi r30, r11, CC_R30
/* special purpose registers */
mfs r12, rmsr
nop
swi r12, r11, CC_MSR
mfs r12, rear
nop
swi r12, r11, CC_EAR
mfs r12, resr
nop
swi r12, r11, CC_ESR
mfs r12, rfsr
nop
swi r12, r11, CC_FSR
/* update r31, the current-give me pointer to task which will be next */
lwi CURRENT_TASK, r6, TI_TASK
/* stored it to current_save too */
swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE)
/* get new process' cpu context and restore */
/* give me start where start context of next task */
addik r11, r6, TI_CPU_CONTEXT
/* non-volatile registers */
lwi r30, r11, CC_R30
lwi r29, r11, CC_R29
lwi r28, r11, CC_R28
lwi r27, r11, CC_R27
lwi r26, r11, CC_R26
lwi r25, r11, CC_R25
lwi r24, r11, CC_R24
lwi r23, r11, CC_R23
lwi r22, r11, CC_R22
lwi r21, r11, CC_R21
lwi r20, r11, CC_R20
lwi r19, r11, CC_R19
/* dedicated registers */
lwi r18, r11, CC_R18
lwi r17, r11, CC_R17
lwi r16, r11, CC_R16
lwi r15, r11, CC_R15
lwi r14, r11, CC_R14
lwi r13, r11, CC_R13
/* skip volatile registers */
lwi r2, r11, CC_R2
lwi r1, r11, CC_R1
/* special purpose registers */
lwi r12, r11, CC_FSR
mts rfsr, r12
nop
lwi r12, r11, CC_MSR
mts rmsr, r12
nop
rtsd r15, 8
nop
ENTRY(_reset)
brai 0x70; /* Jump back to FS-boot */
ENTRY(_break)
mfs r5, rmsr
nop
swi r5, r0, 0x250 + TOPHYS(r0_ram)
mfs r5, resr
nop
swi r5, r0, 0x254 + TOPHYS(r0_ram)
bri 0
/* These are compiled and loaded into high memory, then
* copied into place in mach_early_setup */
.section .init.ivt, "ax"
.org 0x0
/* this is very important - here is the reset vector */
/* in current MMU branch you don't care what is here - it is
* used from bootloader site - but this is correct for FS-BOOT */
brai 0x70
nop
brai TOPHYS(_user_exception); /* syscall handler */
brai TOPHYS(_interrupt); /* Interrupt handler */
brai TOPHYS(_break); /* nmi trap handler */
brai TOPHYS(_hw_exception_handler); /* HW exception handler */
.org 0x60
brai TOPHYS(_debug_exception); /* debug trap handler*/
.section .rodata,"a"
#include "syscall_table.S"
syscall_table_size=(.-sys_call_table)
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