/* * Low-level system-call handling, trap handlers and context-switching * * Copyright (C) 2008-2009 Michal Simek * Copyright (C) 2008-2009 PetaLogix * Copyright (C) 2003 John Williams * Copyright (C) 2001,2002 NEC Corporation * Copyright (C) 2001,2002 Miles Bader * * 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 * Heavily modified by John Williams for Microblaze */ #include #include #include #include #include #include #include #include #include #include #include #include #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