/*
* 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
#ifdef DEBUG
/* Create space for syscalls counting. */
.section .data
.global syscall_debug_table
.align 4
syscall_debug_table:
.space (__NR_syscalls * 4)
#endif /* DEBUG */
#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 r0, MSR_BIP
.endm
.macro set_bip
msrset r0, MSR_BIP
.endm
.macro clear_eip
msrclr r0, MSR_EIP
.endm
.macro set_ee
msrset r0, MSR_EE
.endm
.macro disable_irq
msrclr r0, MSR_IE
.endm
.macro enable_irq
msrset r0, MSR_IE
.endm
.macro set_ums
msrset r0, MSR_UMS
msrclr r0, MSR_VMS
.endm
.macro set_vms
msrclr r0, MSR_UMS
msrset r0, MSR_VMS
.endm
.macro clear_ums
msrclr r0, MSR_UMS
.endm
.macro clear_vms_ums
msrclr r0, MSR_VMS | MSR_UMS
.endm
#else
.macro clear_bip
mfs r11, rmsr
andi r11, r11, ~MSR_BIP
mts rmsr, r11
.endm
.macro set_bip
mfs r11, rmsr
ori r11, r11, MSR_BIP
mts rmsr, r11
.endm
.macro clear_eip
mfs r11, rmsr
andi r11, r11, ~MSR_EIP
mts rmsr, r11
.endm
.macro set_ee
mfs r11, rmsr
ori r11, r11, MSR_EE
mts rmsr, r11
.endm
.macro disable_irq
mfs r11, rmsr
andi r11, r11, ~MSR_IE
mts rmsr, r11
.endm
.macro enable_irq
mfs r11, rmsr
ori r11, r11, MSR_IE
mts rmsr, r11
.endm
.macro set_ums
mfs r11, rmsr
ori r11, r11, MSR_VMS
andni r11, r11, MSR_UMS
mts rmsr, r11
.endm
.macro set_vms
mfs r11, rmsr
ori r11, r11, MSR_VMS
andni r11, r11, MSR_UMS
mts rmsr, r11
.endm
.macro clear_ums
mfs r11, rmsr
andni r11, r11, MSR_UMS
mts rmsr,r11
.endm
.macro clear_vms_ums
mfs r11, rmsr
andni r11, r11, (MSR_VMS|MSR_UMS)
mts rmsr,r11
.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; \
nop; \
2:
/* turn off virtual protected mode save and user mode save*/
#define VM_OFF \
clear_vms_ums; \
rted r0, TOPHYS(1f); \
nop; \
1:
#define SAVE_REGS \
swi r2, r1, PT_R2; /* Save SDA */ \
swi r3, r1, PT_R3; \
swi r4, r1, PT_R4; \
swi r5, r1, PT_R5; \
swi r6, r1, PT_R6; \
swi r7, r1, PT_R7; \
swi r8, r1, PT_R8; \
swi r9, r1, PT_R9; \
swi r10, r1, PT_R10; \
swi r11, r1, PT_R11; /* save clobbered regs after rval */\
swi r12, r1, PT_R12; \
swi r13, r1, PT_R13; /* Save SDA2 */ \
swi r14, r1, PT_PC; /* PC, before IRQ/trap */ \
swi r15, r1, PT_R15; /* Save LP */ \
swi r16, r1, PT_R16; \
swi r17, r1, PT_R17; \
swi r18, r1, PT_R18; /* Save asm scratch reg */ \
swi r19, r1, PT_R19; \
swi r20, r1, PT_R20; \
swi r21, r1, PT_R21; \
swi r22, r1, PT_R22; \
swi r23, r1, PT_R23; \
swi r24, r1, PT_R24; \
swi r25, r1, PT_R25; \
swi r26, r1, PT_R26; \
swi r27, r1, PT_R27; \
swi r28, r1, PT_R28; \
swi r29, r1, PT_R29; \
swi r30, r1, PT_R30; \
swi r31, r1, PT_R31; /* Save current task reg */ \
mfs r11, rmsr; /* save MSR */ \
swi r11, r1, PT_MSR;
#define RESTORE_REGS \
lwi r11, r1, PT_MSR; \
mts rmsr , r11; \
lwi r2, r1, PT_R2; /* restore SDA */ \
lwi r3, r1, PT_R3; \
lwi r4, r1, PT_R4; \
lwi r5, r1, PT_R5; \
lwi r6, r1, PT_R6; \
lwi r7, r1, PT_R7; \
lwi r8, r1, PT_R8; \
lwi r9, r1, PT_R9; \
lwi r10, r1, PT_R10; \
lwi r11, r1, PT_R11; /* restore clobbered regs after rval */\
lwi r12, r1, PT_R12; \
lwi r13, r1, PT_R13; /* restore SDA2 */ \
lwi r14, r1, PT_PC; /* RESTORE_LINK PC, before IRQ/trap */\
lwi r15, r1, PT_R15; /* restore LP */ \
lwi r16, r1, PT_R16; \
lwi r17, r1, PT_R17; \
lwi r18, r1, PT_R18; /* restore asm scratch reg */ \
lwi r19, r1, PT_R19; \
lwi r20, r1, PT_R20; \
lwi r21, r1, PT_R21; \
lwi r22, r1, PT_R22; \
lwi r23, r1, PT_R23; \
lwi r24, r1, PT_R24; \
lwi r25, r1, PT_R25; \
lwi r26, r1, PT_R26; \
lwi r27, r1, PT_R27; \
lwi r28, r1, PT_R28; \
lwi r29, r1, PT_R29; \
lwi r30, r1, PT_R30; \
lwi r31, r1, PT_R31; /* Restore cur task reg */
#define SAVE_STATE \
swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)); /* save stack */ \
/* See if already in kernel mode.*/ \
mfs r1, rmsr; \
andi r1, r1, MSR_UMS; \
bnei r1, 1f; \
/* Kernel-mode state save. */ \
/* Reload kernel stack-ptr. */ \
lwi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)); \
/* FIXME: I can add these two lines to one */ \
/* tophys(r1,r1); */ \
/* addik r1, r1, -PT_SIZE; */ \
addik r1, r1, CONFIG_KERNEL_BASE_ADDR - CONFIG_KERNEL_START - PT_SIZE; \
SAVE_REGS \
brid 2f; \
swi r1, r1, PT_MODE; \
1: /* User-mode state save. */ \
lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); /* get saved current */\
tophys(r1,r1); \
lwi r1, r1, TS_THREAD_INFO; /* get the thread info */ \
/* MS these three instructions can be added to one */ \
/* addik r1, r1, THREAD_SIZE; */ \
/* tophys(r1,r1); */ \
/* addik r1, r1, -PT_SIZE; */ \
addik r1, r1, THREAD_SIZE + CONFIG_KERNEL_BASE_ADDR - CONFIG_KERNEL_START - PT_SIZE; \
SAVE_REGS \
lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP)); \
swi r11, r1, PT_R1; /* Store user SP. */ \
swi r0, r1, PT_MODE; /* Was in user-mode. */ \
/* MS: I am clearing UMS even in case when I come from kernel space */ \
clear_ums; \
2: lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
.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 */
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, -PT_SIZE; /* Make room on the stack. */
SAVE_REGS
swi r0, r1, PT_R3
swi r0, r1, PT_R4
swi r0, r1, PT_MODE; /* Was in user-mode. */
lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
swi r11, r1, PT_R1; /* Store user SP. */
clear_ums;
2: lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
/* Save away the syscall number. */
swi r12, r1, 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 */
rtbd r0, 3f
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, PT_R3
brlid r15, do_syscall_trace_enter
addik r5, r1, PT_R0
# do_syscall_trace_enter returns the new syscall nr.
addk r12, r0, r3
lwi r5, r1, PT_R5;
lwi r6, r1, PT_R6;
lwi r7, r1, PT_R7;
lwi r8, r1, PT_R8;
lwi r9, r1, PT_R9;
lwi r10, r1, 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;
addi r30, r0, 1 /* restarts allowed */
#ifdef DEBUG
/* Trac syscalls and stored them to syscall_debug_table */
/* The first syscall location stores total syscall number */
lwi r3, r0, syscall_debug_table
addi r3, r3, 1
swi r3, r0, syscall_debug_table
lwi r3, r12, syscall_debug_table
addi r3, r3, 1
swi r3, r12, syscall_debug_table
#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 */
addi r15, r0, ret_from_trap-8
bra r12
/* The syscall number is invalid, return an error. */
5:
rtsd r15, 8; /* looks like a normal subroutine return */
addi r3, r0, -ENOSYS;
/* Entry point used to return from a syscall/trap */
/* We re-enable BIP bit before state restore */
C_ENTRY(ret_from_trap):
swi r3, r1, PT_R3
swi r4, r1, PT_R4
lwi r11, r1, PT_MODE;
/* See if returning to kernel mode, if so, skip resched &c. */
bnei r11, 2f;
/* 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, 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 r19, r11, TI_FLAGS; /* get flags in thread info */
andi r11, r19, _TIF_NEED_RESCHED;
beqi r11, 5f;
bralid r15, schedule; /* Call scheduler */
nop; /* delay slot */
bri 1b
/* Maybe handle a signal */
5:
andi r11, r19, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME;
beqi r11, 4f; /* Signals to handle, handle them */
addik r5, r1, 0; /* Arg 1: struct pt_regs *regs */
bralid r15, do_notify_resume; /* Handle any signals */
add r6, r30, r0; /* Arg 2: int in_syscall */
add r30, r0, r0 /* no more restarts */
bri 1b
/* Finally, return to user state. */
4: set_bip; /* Ints masked for state restore */
swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */
VM_OFF;
tophys(r1,r1);
RESTORE_REGS;
addik r1, r1, PT_SIZE /* Clean up stack space. */
lwi r1, r1, PT_R1 - PT_SIZE;/* Restore user stack pointer. */
bri 6f;
/* Return to kernel state. */
2: set_bip; /* Ints masked for state restore */
VM_OFF;
tophys(r1,r1);
RESTORE_REGS;
addik r1, r1, PT_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;
/* 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 r5, r3, r0; /* switch_thread returns the prev task */
/* ( in the delay slot ) */
brid ret_from_trap; /* Do normal trap return */
add r3, r0, r0; /* Child's fork call should return 0. */
C_ENTRY(ret_from_kernel_thread):
bralid r15, schedule_tail; /* ...which is schedule_tail's arg */
add r5, r3, r0; /* switch_thread returns the prev task */
/* ( in the delay slot ) */
brald r15, r20 /* fn was left in r20 */
addk r5, r0, r19 /* ... and argument - in r19 */
brid ret_from_trap
add r3, r0, r0
C_ENTRY(sys_rt_sigreturn_wrapper):
addik r30, r0, 0 /* no restarts */
brid sys_rt_sigreturn /* Do real work */
addik r5, r1, 0; /* add user context as 1st arg */
/*
* HW EXCEPTION rutine start
*/
C_ENTRY(full_exception_trap):
/* adjust exception address for privileged instruction
* for finding where is it */
addik r17, r17, -4
SAVE_STATE /* Save registers */
/* PC, before IRQ/trap - this is one instruction above */
swi r17, r1, PT_PC;
tovirt(r1,r1)
/* 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 */
addik r15, r0, ret_from_exc - 8
mfs r6, resr
mfs r7, rfsr; /* save FSR */
mts rfsr, r0; /* Clear sticky fsr */
rted r0, full_exception
addik r5, r1, 0 /* parameter struct pt_regs * regs */
/*
* 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):
/* MS: I have to save r11 value and then restore it because
* set_bit, clear_eip, set_ee use r11 as temp register if MSR
* instructions are not used. We don't need to do if MSR instructions
* are used and they use r0 instead of r11.
* I am using ENTRY_SP which should be primary used only for stack
* pointer saving. */
swi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
set_bip; /* equalize initial state for all possible entries */
clear_eip;
set_ee;
lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
SAVE_STATE /* Save registers.*/
/* PC, before IRQ/trap - this is one instruction above */
swi r17, r1, PT_PC;
tovirt(r1,r1)
/* where the trap should return need -8 to adjust for rtsd r15, 8 */
addik r15, r0, ret_from_exc-8
mfs r3, resr /* ESR */
mfs r4, rear /* EAR */
rtbd r0, _unaligned_data_exception
addik r7, r1, 0 /* parameter struct pt_regs * regs */
/*
* 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):
SAVE_STATE /* Save registers.*/
/* PC, before IRQ/trap - this is one instruction above */
swi r17, r1, PT_PC;
tovirt(r1,r1)
/* where the trap should return need -8 to adjust for rtsd r15, 8 */
addik r15, r0, ret_from_exc-8
mfs r6, rear /* parameter unsigned long address */
mfs r7, resr /* parameter unsigned long error_code */
rted r0, do_page_fault
addik r5, r1, 0 /* parameter struct pt_regs * regs */
C_ENTRY(page_fault_instr_trap):
SAVE_STATE /* Save registers.*/
/* PC, before IRQ/trap - this is one instruction above */
swi r17, r1, PT_PC;
tovirt(r1,r1)
/* where the trap should return need -8 to adjust for rtsd r15, 8 */
addik r15, r0, ret_from_exc-8
mfs r6, rear /* parameter unsigned long address */
ori r7, r0, 0 /* parameter unsigned long error_code */
rted r0, do_page_fault
addik r5, r1, 0 /* parameter struct pt_regs * regs */
/* Entry point used to return from an exception. */
C_ENTRY(ret_from_exc):
lwi r11, r1, 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. */
1:
lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
lwi r19, r11, TI_FLAGS; /* get flags in thread info */
andi r11, r19, _TIF_NEED_RESCHED;
beqi r11, 5f;
/* Call the scheduler before returning from a syscall/trap. */
bralid r15, schedule; /* Call scheduler */
nop; /* delay slot */
bri 1b
/* Maybe handle a signal */
5: andi r11, r19, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME;
beqi r11, 4f; /* 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_notify_resume returns. */
addik r5, r1, 0; /* Arg 1: struct pt_regs *regs */
bralid r15, do_notify_resume; /* Handle any signals */
addi r6, r0, 0; /* Arg 2: int in_syscall */
bri 1b
/* Finally, return to user state. */
4: set_bip; /* Ints masked for state restore */
swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */
VM_OFF;
tophys(r1,r1);
RESTORE_REGS;
addik r1, r1, PT_SIZE /* Clean up stack space. */
lwi r1, r1, PT_R1 - PT_SIZE; /* Restore user stack pointer. */
bri 6f;
/* Return to kernel state. */
2: set_bip; /* Ints masked for state restore */
VM_OFF;
tophys(r1,r1);
RESTORE_REGS;
addik r1, r1, PT_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))
/* MS: See if already in kernel mode. */
mfs r1, rmsr
nop
andi r1, r1, MSR_UMS
bnei r1, 1f
/* Kernel-mode state save. */
lwi r1, r0, TOPHYS(PER_CPU(ENTRY_SP))
tophys(r1,r1); /* MS: I have in r1 physical address where stack is */
/* save registers */
/* MS: Make room on the stack -> activation record */
addik r1, r1, -PT_SIZE;
SAVE_REGS
brid 2f;
swi r1, r1, PT_MODE; /* 0 - user mode, 1 - kernel mode */
1:
/* User-mode state 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, -PT_SIZE;
SAVE_REGS
/* calculate mode */
swi r0, r1, PT_MODE;
lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
swi r11, r1, PT_R1;
clear_ums;
2:
lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
tovirt(r1,r1)
addik r15, r0, irq_call;
irq_call:rtbd r0, do_IRQ;
addik r5, r1, 0;
/* MS: we are in virtual mode */
ret_from_irq:
lwi r11, r1, PT_MODE;
bnei r11, 2f;
1:
lwi r11, CURRENT_TASK, TS_THREAD_INFO;
lwi r19, r11, TI_FLAGS; /* MS: get flags from thread info */
andi r11, r19, _TIF_NEED_RESCHED;
beqi r11, 5f
bralid r15, schedule;
nop; /* delay slot */
bri 1b
/* Maybe handle a signal */
5: andi r11, r19, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME;
beqid r11, no_intr_resched
/* Handle a signal return; Pending signals should be in r18. */
addik r5, r1, 0; /* Arg 1: struct pt_regs *regs */
bralid r15, do_notify_resume; /* Handle any signals */
addi r6, r0, 0; /* Arg 2: int in_syscall */
bri 1b
/* Finally, return to user state. */
no_intr_resched:
/* Disable interrupts, we are now committed to the state restore */
disable_irq
swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE);
VM_OFF;
tophys(r1,r1);
RESTORE_REGS
addik r1, r1, PT_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)
RESTORE_REGS
addik r1, r1, PT_SIZE /* MS: Clean up stack space. */
tovirt(r1,r1);
6:
IRQ_return: /* MS: Make global symbol for debugging */
rtid r14, 0
nop
/*
* Debug trap for KGDB. Enter to _debug_exception by brki r16, 0x18
* and call handling function with saved pt_regs
*/
C_ENTRY(_debug_exception):
/* BIP bit is set on entry, no interrupts can occur */
swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP))
mfs r1, rmsr
nop
andi r1, r1, MSR_UMS
bnei r1, 1f
/* MS: Kernel-mode state save - kgdb */
lwi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)); /* Reload kernel stack-ptr*/
/* BIP bit is set on entry, no interrupts can occur */
addik r1, r1, CONFIG_KERNEL_BASE_ADDR - CONFIG_KERNEL_START - PT_SIZE;
SAVE_REGS;
/* save all regs to pt_reg structure */
swi r0, r1, PT_R0; /* R0 must be saved too */
swi r14, r1, PT_R14 /* rewrite saved R14 value */
swi r16, r1, PT_PC; /* PC and r16 are the same */
/* save special purpose registers to pt_regs */
mfs r11, rear;
swi r11, r1, PT_EAR;
mfs r11, resr;
swi r11, r1, PT_ESR;
mfs r11, rfsr;
swi r11, r1, PT_FSR;
/* stack pointer is in physical address at it is decrease
* by PT_SIZE but we need to get correct R1 value */
addik r11, r1, CONFIG_KERNEL_START - CONFIG_KERNEL_BASE_ADDR + PT_SIZE;
swi r11, r1, PT_R1
/* MS: r31 - current pointer isn't changed */
tovirt(r1,r1)
#ifdef CONFIG_KGDB
addi r5, r1, 0 /* pass pt_reg address as the first arg */
addik r15, r0, dbtrap_call; /* return address */
rtbd r0, microblaze_kgdb_break
nop;
#endif
/* MS: Place handler for brki from kernel space if KGDB is OFF.
* It is very unlikely that another brki instruction is called. */
bri 0
/* MS: User-mode state save - gdb */
1: 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, -PT_SIZE; /* Make room on the stack. */
SAVE_REGS;
swi r16, r1, PT_PC; /* Save LP */
swi r0, r1, PT_MODE; /* Was in user-mode. */
lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
swi r11, r1, PT_R1; /* Store user SP. */
lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
tovirt(r1,r1)
set_vms;
addik r5, r1, 0;
addik r15, r0, dbtrap_call;
dbtrap_call: /* Return point for kernel/user entry + 8 because of rtsd r15, 8 */
rtbd r0, sw_exception
nop
/* MS: The first instruction for the second part of the gdb/kgdb */
set_bip; /* Ints masked for state restore */
lwi r11, r1, PT_MODE;
bnei r11, 2f;
/* MS: Return to user space - gdb */
1:
/* Get current task ptr into r11 */
lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
lwi r19, r11, TI_FLAGS; /* get flags in thread info */
andi r11, r19, _TIF_NEED_RESCHED;
beqi r11, 5f;
/* Call the scheduler before returning from a syscall/trap. */
bralid r15, schedule; /* Call scheduler */
nop; /* delay slot */
bri 1b
/* Maybe handle a signal */
5: andi r11, r19, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME;
beqi r11, 4f; /* Signals to handle, handle them */
addik r5, r1, 0; /* Arg 1: struct pt_regs *regs */
bralid r15, do_notify_resume; /* Handle any signals */
addi r6, r0, 0; /* Arg 2: int in_syscall */
bri 1b
/* Finally, return to user state. */
4: swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */
VM_OFF;
tophys(r1,r1);
/* MS: Restore all regs */
RESTORE_REGS
addik r1, r1, PT_SIZE /* Clean up stack space */
lwi r1, r1, PT_R1 - PT_SIZE; /* Restore user stack pointer */
DBTRAP_return_user: /* MS: Make global symbol for debugging */
rtbd r16, 0; /* MS: Instructions to return from a debug trap */
nop;
/* MS: Return to kernel state - kgdb */
2: VM_OFF;
tophys(r1,r1);
/* MS: Restore all regs */
RESTORE_REGS
lwi r14, r1, PT_R14;
lwi r16, r1, PT_PC;
addik r1, r1, PT_SIZE; /* MS: Clean up stack space */
tovirt(r1,r1);
DBTRAP_return_kernel: /* MS: Make global symbol for debugging */
rtbd r16, 0; /* MS: Instructions to return from a debug trap */
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
swi r12, r11, CC_MSR
mfs r12, rear
swi r12, r11, CC_EAR
mfs r12, resr
swi r12, r11, CC_ESR
mfs r12, rfsr
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
lwi r12, r11, CC_MSR
mts rmsr, r12
rtsd r15, 8
nop
ENTRY(_reset)
brai 0; /* Jump to reset vector */
/* These are compiled and loaded into high memory, then
* copied into place in mach_early_setup */
.section .init.ivt, "ax"
#if CONFIG_MANUAL_RESET_VECTOR
.org 0x0
brai CONFIG_MANUAL_RESET_VECTOR
#endif
.org 0x8
brai TOPHYS(_user_exception); /* syscall handler */
.org 0x10
brai TOPHYS(_interrupt); /* Interrupt handler */
.org 0x18
brai TOPHYS(_debug_exception); /* debug trap handler */
.org 0x20
brai TOPHYS(_hw_exception_handler); /* HW exception handler */
.section .rodata,"a"
#include "syscall_table.S"
syscall_table_size=(.-sys_call_table)
type_SYSCALL:
.ascii "SYSCALL\0"
type_IRQ:
.ascii "IRQ\0"
type_IRQ_PREEMPT:
.ascii "IRQ (PREEMPTED)\0"
type_SYSCALL_PREEMPT:
.ascii " SYSCALL (PREEMPTED)\0"
/*
* Trap decoding for stack unwinder
* Tuples are (start addr, end addr, string)
* If return address lies on [start addr, end addr],
* unwinder displays 'string'
*/
.align 4
.global microblaze_trap_handlers
microblaze_trap_handlers:
/* Exact matches come first */
.word ret_from_trap; .word ret_from_trap ; .word type_SYSCALL
.word ret_from_irq ; .word ret_from_irq ; .word type_IRQ
/* Fuzzy matches go here */
.word ret_from_irq ; .word no_intr_resched ; .word type_IRQ_PREEMPT
.word ret_from_trap; .word TRAP_return ; .word type_SYSCALL_PREEMPT
/* End of table */
.word 0 ; .word 0 ; .word 0