/* SPDX-License-Identifier: GPL-2.0-or-later */ /* * OpenRISC entry.S * * Linux architectural port borrowing liberally from similar works of * others. All original copyrights apply as per the original source * declaration. * * Modifications for the OpenRISC architecture: * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com> * Copyright (C) 2005 Gyorgy Jeney <nog@bsemi.com> * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se> */ #include <linux/linkage.h> #include <linux/pgtable.h> #include <asm/processor.h> #include <asm/unistd.h> #include <asm/thread_info.h> #include <asm/errno.h> #include <asm/spr_defs.h> #include <asm/page.h> #include <asm/mmu.h> #include <asm/asm-offsets.h> #define DISABLE_INTERRUPTS(t1,t2) \ l.mfspr t2,r0,SPR_SR ;\ l.movhi t1,hi(~(SPR_SR_IEE|SPR_SR_TEE)) ;\ l.ori t1,t1,lo(~(SPR_SR_IEE|SPR_SR_TEE)) ;\ l.and t2,t2,t1 ;\ l.mtspr r0,t2,SPR_SR #define ENABLE_INTERRUPTS(t1) \ l.mfspr t1,r0,SPR_SR ;\ l.ori t1,t1,lo(SPR_SR_IEE|SPR_SR_TEE) ;\ l.mtspr r0,t1,SPR_SR /* =========================================================[ macros ]=== */ #ifdef CONFIG_TRACE_IRQFLAGS /* * Trace irq on/off creating a stack frame. */ #define TRACE_IRQS_OP(trace_op) \ l.sw -8(r1),r2 /* store frame pointer */ ;\ l.sw -4(r1),r9 /* store return address */ ;\ l.addi r2,r1,0 /* move sp to fp */ ;\ l.jal trace_op ;\ l.addi r1,r1,-8 ;\ l.ori r1,r2,0 /* restore sp */ ;\ l.lwz r9,-4(r1) /* restore return address */ ;\ l.lwz r2,-8(r1) /* restore fp */ ;\ /* * Trace irq on/off and save registers we need that would otherwise be * clobbered. */ #define TRACE_IRQS_SAVE(t1,trace_op) \ l.sw -12(r1),t1 /* save extra reg */ ;\ l.sw -8(r1),r2 /* store frame pointer */ ;\ l.sw -4(r1),r9 /* store return address */ ;\ l.addi r2,r1,0 /* move sp to fp */ ;\ l.jal trace_op ;\ l.addi r1,r1,-12 ;\ l.ori r1,r2,0 /* restore sp */ ;\ l.lwz r9,-4(r1) /* restore return address */ ;\ l.lwz r2,-8(r1) /* restore fp */ ;\ l.lwz t1,-12(r1) /* restore extra reg */ #define TRACE_IRQS_OFF TRACE_IRQS_OP(trace_hardirqs_off) #define TRACE_IRQS_ON TRACE_IRQS_OP(trace_hardirqs_on) #define TRACE_IRQS_ON_SYSCALL \ TRACE_IRQS_SAVE(r10,trace_hardirqs_on) ;\ l.lwz r3,PT_GPR3(r1) ;\ l.lwz r4,PT_GPR4(r1) ;\ l.lwz r5,PT_GPR5(r1) ;\ l.lwz r6,PT_GPR6(r1) ;\ l.lwz r7,PT_GPR7(r1) ;\ l.lwz r8,PT_GPR8(r1) ;\ l.lwz r11,PT_GPR11(r1) #define TRACE_IRQS_OFF_ENTRY \ l.lwz r5,PT_SR(r1) ;\ l.andi r3,r5,(SPR_SR_IEE|SPR_SR_TEE) ;\ l.sfeq r5,r0 /* skip trace if irqs were already off */;\ l.bf 1f ;\ l.nop ;\ TRACE_IRQS_SAVE(r4,trace_hardirqs_off) ;\ 1: #else #define TRACE_IRQS_OFF #define TRACE_IRQS_ON #define TRACE_IRQS_OFF_ENTRY #define TRACE_IRQS_ON_SYSCALL #endif /* * We need to disable interrupts at beginning of RESTORE_ALL * since interrupt might come in after we've loaded EPC return address * and overwrite EPC with address somewhere in RESTORE_ALL * which is of course wrong! */ #define RESTORE_ALL \ DISABLE_INTERRUPTS(r3,r4) ;\ l.lwz r3,PT_PC(r1) ;\ l.mtspr r0,r3,SPR_EPCR_BASE ;\ l.lwz r3,PT_SR(r1) ;\ l.mtspr r0,r3,SPR_ESR_BASE ;\ l.lwz r2,PT_GPR2(r1) ;\ l.lwz r3,PT_GPR3(r1) ;\ l.lwz r4,PT_GPR4(r1) ;\ l.lwz r5,PT_GPR5(r1) ;\ l.lwz r6,PT_GPR6(r1) ;\ l.lwz r7,PT_GPR7(r1) ;\ l.lwz r8,PT_GPR8(r1) ;\ l.lwz r9,PT_GPR9(r1) ;\ l.lwz r10,PT_GPR10(r1) ;\ l.lwz r11,PT_GPR11(r1) ;\ l.lwz r12,PT_GPR12(r1) ;\ l.lwz r13,PT_GPR13(r1) ;\ l.lwz r14,PT_GPR14(r1) ;\ l.lwz r15,PT_GPR15(r1) ;\ l.lwz r16,PT_GPR16(r1) ;\ l.lwz r17,PT_GPR17(r1) ;\ l.lwz r18,PT_GPR18(r1) ;\ l.lwz r19,PT_GPR19(r1) ;\ l.lwz r20,PT_GPR20(r1) ;\ l.lwz r21,PT_GPR21(r1) ;\ l.lwz r22,PT_GPR22(r1) ;\ l.lwz r23,PT_GPR23(r1) ;\ l.lwz r24,PT_GPR24(r1) ;\ l.lwz r25,PT_GPR25(r1) ;\ l.lwz r26,PT_GPR26(r1) ;\ l.lwz r27,PT_GPR27(r1) ;\ l.lwz r28,PT_GPR28(r1) ;\ l.lwz r29,PT_GPR29(r1) ;\ l.lwz r30,PT_GPR30(r1) ;\ l.lwz r31,PT_GPR31(r1) ;\ l.lwz r1,PT_SP(r1) ;\ l.rfe #define EXCEPTION_ENTRY(handler) \ .global handler ;\ handler: ;\ /* r1, EPCR, ESR a already saved */ ;\ l.sw PT_GPR2(r1),r2 ;\ l.sw PT_GPR3(r1),r3 ;\ /* r4 already save */ ;\ l.sw PT_GPR5(r1),r5 ;\ l.sw PT_GPR6(r1),r6 ;\ l.sw PT_GPR7(r1),r7 ;\ l.sw PT_GPR8(r1),r8 ;\ l.sw PT_GPR9(r1),r9 ;\ /* r10 already saved */ ;\ l.sw PT_GPR11(r1),r11 ;\ /* r12 already saved */ ;\ l.sw PT_GPR13(r1),r13 ;\ l.sw PT_GPR14(r1),r14 ;\ l.sw PT_GPR15(r1),r15 ;\ l.sw PT_GPR16(r1),r16 ;\ l.sw PT_GPR17(r1),r17 ;\ l.sw PT_GPR18(r1),r18 ;\ l.sw PT_GPR19(r1),r19 ;\ l.sw PT_GPR20(r1),r20 ;\ l.sw PT_GPR21(r1),r21 ;\ l.sw PT_GPR22(r1),r22 ;\ l.sw PT_GPR23(r1),r23 ;\ l.sw PT_GPR24(r1),r24 ;\ l.sw PT_GPR25(r1),r25 ;\ l.sw PT_GPR26(r1),r26 ;\ l.sw PT_GPR27(r1),r27 ;\ l.sw PT_GPR28(r1),r28 ;\ l.sw PT_GPR29(r1),r29 ;\ /* r30 already save */ ;\ l.sw PT_GPR31(r1),r31 ;\ TRACE_IRQS_OFF_ENTRY ;\ /* Store -1 in orig_gpr11 for non-syscall exceptions */ ;\ l.addi r30,r0,-1 ;\ l.sw PT_ORIG_GPR11(r1),r30 #define UNHANDLED_EXCEPTION(handler,vector) \ .global handler ;\ handler: ;\ /* r1, EPCR, ESR already saved */ ;\ l.sw PT_GPR2(r1),r2 ;\ l.sw PT_GPR3(r1),r3 ;\ l.sw PT_GPR5(r1),r5 ;\ l.sw PT_GPR6(r1),r6 ;\ l.sw PT_GPR7(r1),r7 ;\ l.sw PT_GPR8(r1),r8 ;\ l.sw PT_GPR9(r1),r9 ;\ /* r10 already saved */ ;\ l.sw PT_GPR11(r1),r11 ;\ /* r12 already saved */ ;\ l.sw PT_GPR13(r1),r13 ;\ l.sw PT_GPR14(r1),r14 ;\ l.sw PT_GPR15(r1),r15 ;\ l.sw PT_GPR16(r1),r16 ;\ l.sw PT_GPR17(r1),r17 ;\ l.sw PT_GPR18(r1),r18 ;\ l.sw PT_GPR19(r1),r19 ;\ l.sw PT_GPR20(r1),r20 ;\ l.sw PT_GPR21(r1),r21 ;\ l.sw PT_GPR22(r1),r22 ;\ l.sw PT_GPR23(r1),r23 ;\ l.sw PT_GPR24(r1),r24 ;\ l.sw PT_GPR25(r1),r25 ;\ l.sw PT_GPR26(r1),r26 ;\ l.sw PT_GPR27(r1),r27 ;\ l.sw PT_GPR28(r1),r28 ;\ l.sw PT_GPR29(r1),r29 ;\ /* r30 already saved */ ;\ l.sw PT_GPR31(r1),r31 ;\ /* Store -1 in orig_gpr11 for non-syscall exceptions */ ;\ l.addi r30,r0,-1 ;\ l.sw PT_ORIG_GPR11(r1),r30 ;\ l.addi r3,r1,0 ;\ /* r4 is exception EA */ ;\ l.addi r5,r0,vector ;\ l.jal unhandled_exception ;\ l.nop ;\ l.j _ret_from_exception ;\ l.nop /* clobbers 'reg' */ #define CLEAR_LWA_FLAG(reg) \ l.movhi reg,hi(lwa_flag) ;\ l.ori reg,reg,lo(lwa_flag) ;\ l.sw 0(reg),r0 /* * NOTE: one should never assume that SPR_EPC, SPR_ESR, SPR_EEAR * contain the same values as when exception we're handling * occured. in fact they never do. if you need them use * values saved on stack (for SPR_EPC, SPR_ESR) or content * of r4 (for SPR_EEAR). for details look at EXCEPTION_HANDLE() * in 'arch/openrisc/kernel/head.S' */ /* =====================================================[ exceptions] === */ __REF /* ---[ 0x100: RESET exception ]----------------------------------------- */ EXCEPTION_ENTRY(_tng_kernel_start) l.jal _start l.andi r0,r0,0 /* ---[ 0x200: BUS exception ]------------------------------------------- */ EXCEPTION_ENTRY(_bus_fault_handler) CLEAR_LWA_FLAG(r3) /* r4: EA of fault (set by EXCEPTION_HANDLE) */ l.jal do_bus_fault l.addi r3,r1,0 /* pt_regs */ l.j _ret_from_exception l.nop /* ---[ 0x300: Data Page Fault exception ]------------------------------- */ EXCEPTION_ENTRY(_dtlb_miss_page_fault_handler) CLEAR_LWA_FLAG(r3) l.and r5,r5,r0 l.j 1f l.nop EXCEPTION_ENTRY(_data_page_fault_handler) CLEAR_LWA_FLAG(r3) /* set up parameters for do_page_fault */ l.ori r5,r0,0x300 // exception vector 1: l.addi r3,r1,0 // pt_regs /* r4 set be EXCEPTION_HANDLE */ // effective address of fault #ifdef CONFIG_OPENRISC_NO_SPR_SR_DSX l.lwz r6,PT_PC(r3) // address of an offending insn l.lwz r6,0(r6) // instruction that caused pf l.srli r6,r6,26 // check opcode for jump insn l.sfeqi r6,0 // l.j l.bf 8f l.sfeqi r6,1 // l.jal l.bf 8f l.sfeqi r6,3 // l.bnf l.bf 8f l.sfeqi r6,4 // l.bf l.bf 8f l.sfeqi r6,0x11 // l.jr l.bf 8f l.sfeqi r6,0x12 // l.jalr l.bf 8f l.nop l.j 9f l.nop 8: // offending insn is in delay slot l.lwz r6,PT_PC(r3) // address of an offending insn l.addi r6,r6,4 l.lwz r6,0(r6) // instruction that caused pf l.srli r6,r6,26 // get opcode 9: // offending instruction opcode loaded in r6 #else l.mfspr r6,r0,SPR_SR // SR l.andi r6,r6,SPR_SR_DSX // check for delay slot exception l.sfne r6,r0 // exception happened in delay slot l.bnf 7f l.lwz r6,PT_PC(r3) // address of an offending insn l.addi r6,r6,4 // offending insn is in delay slot 7: l.lwz r6,0(r6) // instruction that caused pf l.srli r6,r6,26 // check opcode for write access #endif l.sfgeui r6,0x33 // check opcode for write access l.bnf 1f l.sfleui r6,0x37 l.bnf 1f l.ori r6,r0,0x1 // write access l.j 2f l.nop 1: l.ori r6,r0,0x0 // !write access 2: /* call fault.c handler in openrisc/mm/fault.c */ l.jal do_page_fault l.nop l.j _ret_from_exception l.nop /* ---[ 0x400: Insn Page Fault exception ]------------------------------- */ EXCEPTION_ENTRY(_itlb_miss_page_fault_handler) CLEAR_LWA_FLAG(r3) l.and r5,r5,r0 l.j 1f l.nop EXCEPTION_ENTRY(_insn_page_fault_handler) CLEAR_LWA_FLAG(r3) /* set up parameters for do_page_fault */ l.ori r5,r0,0x400 // exception vector 1: l.addi r3,r1,0 // pt_regs /* r4 set be EXCEPTION_HANDLE */ // effective address of fault l.ori r6,r0,0x0 // !write access /* call fault.c handler in openrisc/mm/fault.c */ l.jal do_page_fault l.nop l.j _ret_from_exception l.nop /* ---[ 0x500: Timer exception ]----------------------------------------- */ EXCEPTION_ENTRY(_timer_handler) CLEAR_LWA_FLAG(r3) l.jal timer_interrupt l.addi r3,r1,0 /* pt_regs */ l.j _ret_from_intr l.nop /* ---[ 0x600: Alignment exception ]-------------------------------------- */ EXCEPTION_ENTRY(_alignment_handler) CLEAR_LWA_FLAG(r3) /* r4: EA of fault (set by EXCEPTION_HANDLE) */ l.jal do_unaligned_access l.addi r3,r1,0 /* pt_regs */ l.j _ret_from_exception l.nop #if 0 EXCEPTION_ENTRY(_alignment_handler) // l.mfspr r2,r0,SPR_EEAR_BASE /* Load the effective address */ l.addi r2,r4,0 // l.mfspr r5,r0,SPR_EPCR_BASE /* Load the insn address */ l.lwz r5,PT_PC(r1) l.lwz r3,0(r5) /* Load insn */ l.srli r4,r3,26 /* Shift left to get the insn opcode */ l.sfeqi r4,0x00 /* Check if the load/store insn is in delay slot */ l.bf jmp l.sfeqi r4,0x01 l.bf jmp l.sfeqi r4,0x03 l.bf jmp l.sfeqi r4,0x04 l.bf jmp l.sfeqi r4,0x11 l.bf jr l.sfeqi r4,0x12 l.bf jr l.nop l.j 1f l.addi r5,r5,4 /* Increment PC to get return insn address */ jmp: l.slli r4,r3,6 /* Get the signed extended jump length */ l.srai r4,r4,4 l.lwz r3,4(r5) /* Load the real load/store insn */ l.add r5,r5,r4 /* Calculate jump target address */ l.j 1f l.srli r4,r3,26 /* Shift left to get the insn opcode */ jr: l.slli r4,r3,9 /* Shift to get the reg nb */ l.andi r4,r4,0x7c l.lwz r3,4(r5) /* Load the real load/store insn */ l.add r4,r4,r1 /* Load the jump register value from the stack */ l.lwz r5,0(r4) l.srli r4,r3,26 /* Shift left to get the insn opcode */ 1: // l.mtspr r0,r5,SPR_EPCR_BASE l.sw PT_PC(r1),r5 l.sfeqi r4,0x26 l.bf lhs l.sfeqi r4,0x25 l.bf lhz l.sfeqi r4,0x22 l.bf lws l.sfeqi r4,0x21 l.bf lwz l.sfeqi r4,0x37 l.bf sh l.sfeqi r4,0x35 l.bf sw l.nop 1: l.j 1b /* I don't know what to do */ l.nop lhs: l.lbs r5,0(r2) l.slli r5,r5,8 l.lbz r6,1(r2) l.or r5,r5,r6 l.srli r4,r3,19 l.andi r4,r4,0x7c l.add r4,r4,r1 l.j align_end l.sw 0(r4),r5 lhz: l.lbz r5,0(r2) l.slli r5,r5,8 l.lbz r6,1(r2) l.or r5,r5,r6 l.srli r4,r3,19 l.andi r4,r4,0x7c l.add r4,r4,r1 l.j align_end l.sw 0(r4),r5 lws: l.lbs r5,0(r2) l.slli r5,r5,24 l.lbz r6,1(r2) l.slli r6,r6,16 l.or r5,r5,r6 l.lbz r6,2(r2) l.slli r6,r6,8 l.or r5,r5,r6 l.lbz r6,3(r2) l.or r5,r5,r6 l.srli r4,r3,19 l.andi r4,r4,0x7c l.add r4,r4,r1 l.j align_end l.sw 0(r4),r5 lwz: l.lbz r5,0(r2) l.slli r5,r5,24 l.lbz r6,1(r2) l.slli r6,r6,16 l.or r5,r5,r6 l.lbz r6,2(r2) l.slli r6,r6,8 l.or r5,r5,r6 l.lbz r6,3(r2) l.or r5,r5,r6 l.srli r4,r3,19 l.andi r4,r4,0x7c l.add r4,r4,r1 l.j align_end l.sw 0(r4),r5 sh: l.srli r4,r3,9 l.andi r4,r4,0x7c l.add r4,r4,r1 l.lwz r5,0(r4) l.sb 1(r2),r5 l.srli r5,r5,8 l.j align_end l.sb 0(r2),r5 sw: l.srli r4,r3,9 l.andi r4,r4,0x7c l.add r4,r4,r1 l.lwz r5,0(r4) l.sb 3(r2),r5 l.srli r5,r5,8 l.sb 2(r2),r5 l.srli r5,r5,8 l.sb 1(r2),r5 l.srli r5,r5,8 l.j align_end l.sb 0(r2),r5 align_end: l.j _ret_from_intr l.nop #endif /* ---[ 0x700: Illegal insn exception ]---------------------------------- */ EXCEPTION_ENTRY(_illegal_instruction_handler) /* r4: EA of fault (set by EXCEPTION_HANDLE) */ l.jal do_illegal_instruction l.addi r3,r1,0 /* pt_regs */ l.j _ret_from_exception l.nop /* ---[ 0x800: External interrupt exception ]---------------------------- */ EXCEPTION_ENTRY(_external_irq_handler) #ifdef CONFIG_OPENRISC_ESR_EXCEPTION_BUG_CHECK l.lwz r4,PT_SR(r1) // were interrupts enabled ? l.andi r4,r4,SPR_SR_IEE l.sfeqi r4,0 l.bnf 1f // ext irq enabled, all ok. l.nop #ifdef CONFIG_PRINTK l.addi r1,r1,-0x8 l.movhi r3,hi(42f) l.ori r3,r3,lo(42f) l.sw 0x0(r1),r3 l.jal _printk l.sw 0x4(r1),r4 l.addi r1,r1,0x8 .section .rodata, "a" 42: .string "\n\rESR interrupt bug: in _external_irq_handler (ESR %x)\n\r" .align 4 .previous #endif l.ori r4,r4,SPR_SR_IEE // fix the bug // l.sw PT_SR(r1),r4 1: #endif CLEAR_LWA_FLAG(r3) l.addi r3,r1,0 l.movhi r8,hi(generic_handle_arch_irq) l.ori r8,r8,lo(generic_handle_arch_irq) l.jalr r8 l.nop l.j _ret_from_intr l.nop /* ---[ 0x900: DTLB miss exception ]------------------------------------- */ /* ---[ 0xa00: ITLB miss exception ]------------------------------------- */ /* ---[ 0xb00: Range exception ]----------------------------------------- */ UNHANDLED_EXCEPTION(_vector_0xb00,0xb00) /* ---[ 0xc00: Syscall exception ]--------------------------------------- */ /* * Syscalls are a special type of exception in that they are * _explicitly_ invoked by userspace and can therefore be * held to conform to the same ABI as normal functions with * respect to whether registers are preserved across the call * or not. */ /* Upon syscall entry we just save the callee-saved registers * and not the call-clobbered ones. */ _string_syscall_return: .string "syscall r9:0x%08x -> syscall(%ld) return %ld\0" .align 4 ENTRY(_sys_call_handler) /* r1, EPCR, ESR a already saved */ l.sw PT_GPR2(r1),r2 /* r3-r8 must be saved because syscall restart relies * on us being able to restart the syscall args... technically * they should be clobbered, otherwise */ l.sw PT_GPR3(r1),r3 /* * r4 already saved * r4 holds the EEAR address of the fault, use it as screatch reg and * then load the original r4 */ CLEAR_LWA_FLAG(r4) l.lwz r4,PT_GPR4(r1) l.sw PT_GPR5(r1),r5 l.sw PT_GPR6(r1),r6 l.sw PT_GPR7(r1),r7 l.sw PT_GPR8(r1),r8 l.sw PT_GPR9(r1),r9 /* r10 already saved */ l.sw PT_GPR11(r1),r11 /* orig_gpr11 must be set for syscalls */ l.sw PT_ORIG_GPR11(r1),r11 /* r12,r13 already saved */ /* r14-r28 (even) aren't touched by the syscall fast path below * so we don't need to save them. However, the functions that return * to userspace via a call to switch() DO need to save these because * switch() effectively clobbers them... saving these registers for * such functions is handled in their syscall wrappers (see fork, vfork, * and clone, below). /* r30 is the only register we clobber in the fast path */ /* r30 already saved */ /* l.sw PT_GPR30(r1),r30 */ _syscall_check_trace_enter: /* syscalls run with interrupts enabled */ TRACE_IRQS_ON_SYSCALL ENABLE_INTERRUPTS(r29) // enable interrupts, r29 is temp /* If TIF_SYSCALL_TRACE is set, then we want to do syscall tracing */ l.lwz r30,TI_FLAGS(r10) l.andi r30,r30,_TIF_SYSCALL_TRACE l.sfne r30,r0 l.bf _syscall_trace_enter l.nop _syscall_check: /* Ensure that the syscall number is reasonable */ l.sfgeui r11,__NR_syscalls l.bf _syscall_badsys l.nop _syscall_call: l.movhi r29,hi(sys_call_table) l.ori r29,r29,lo(sys_call_table) l.slli r11,r11,2 l.add r29,r29,r11 l.lwz r29,0(r29) l.jalr r29 l.nop _syscall_return: /* All syscalls return here... just pay attention to ret_from_fork * which does it in a round-about way. */ l.sw PT_GPR11(r1),r11 // save return value #if 0 _syscall_debug: l.movhi r3,hi(_string_syscall_return) l.ori r3,r3,lo(_string_syscall_return) l.ori r27,r0,2 l.sw -4(r1),r27 l.sw -8(r1),r11 l.lwz r29,PT_ORIG_GPR11(r1) l.sw -12(r1),r29 l.lwz r29,PT_GPR9(r1) l.sw -16(r1),r29 l.movhi r27,hi(_printk) l.ori r27,r27,lo(_printk) l.jalr r27 l.addi r1,r1,-16 l.addi r1,r1,16 #endif #if 0 _syscall_show_regs: l.movhi r27,hi(show_registers) l.ori r27,r27,lo(show_registers) l.jalr r27 l.or r3,r1,r1 #endif _syscall_check_trace_leave: /* r30 is a callee-saved register so this should still hold the * _TIF_SYSCALL_TRACE flag from _syscall_check_trace_enter above... * _syscall_trace_leave expects syscall result to be in pt_regs->r11. */ l.sfne r30,r0 l.bf _syscall_trace_leave l.nop /* This is where the exception-return code begins... interrupts need to be * disabled the rest of the way here because we can't afford to miss any * interrupts that set NEED_RESCHED or SIGNALPENDING... really true? */ _syscall_check_work: #ifdef CONFIG_DEBUG_RSEQ l.jal rseq_syscall l.ori r3,r1,0 #endif /* Here we need to disable interrupts */ DISABLE_INTERRUPTS(r27,r29) TRACE_IRQS_OFF l.lwz r30,TI_FLAGS(r10) l.andi r30,r30,_TIF_WORK_MASK l.sfne r30,r0 l.bnf _syscall_resume_userspace l.nop /* Work pending follows a different return path, so we need to * make sure that all the call-saved registers get into pt_regs * before branching... */ l.sw PT_GPR14(r1),r14 l.sw PT_GPR16(r1),r16 l.sw PT_GPR18(r1),r18 l.sw PT_GPR20(r1),r20 l.sw PT_GPR22(r1),r22 l.sw PT_GPR24(r1),r24 l.sw PT_GPR26(r1),r26 l.sw PT_GPR28(r1),r28 /* _work_pending needs to be called with interrupts disabled */ l.j _work_pending l.nop _syscall_resume_userspace: // ENABLE_INTERRUPTS(r29) /* This is the hot path for returning to userspace from a syscall. If there's * work to be done and the branch to _work_pending was taken above, then the * return to userspace will be done via the normal exception return path... * that path restores _all_ registers and will overwrite the "clobbered" * registers with whatever garbage is in pt_regs -- that's OK because those * registers are clobbered anyway and because the extra work is insignificant * in the context of the extra work that _work_pending is doing. /* Once again, syscalls are special and only guarantee to preserve the * same registers as a normal function call */ /* The assumption here is that the registers r14-r28 (even) are untouched and * don't need to be restored... be sure that that's really the case! */ /* This is still too much... we should only be restoring what we actually * clobbered... we should even be using 'scratch' (odd) regs above so that * we don't need to restore anything, hardly... */ l.lwz r2,PT_GPR2(r1) /* Restore args */ /* r3-r8 are technically clobbered, but syscall restart needs these * to be restored... */ l.lwz r3,PT_GPR3(r1) l.lwz r4,PT_GPR4(r1) l.lwz r5,PT_GPR5(r1) l.lwz r6,PT_GPR6(r1) l.lwz r7,PT_GPR7(r1) l.lwz r8,PT_GPR8(r1) l.lwz r9,PT_GPR9(r1) l.lwz r10,PT_GPR10(r1) l.lwz r11,PT_GPR11(r1) /* r30 is the only register we clobber in the fast path */ l.lwz r30,PT_GPR30(r1) /* Here we use r13-r19 (odd) as scratch regs */ l.lwz r13,PT_PC(r1) l.lwz r15,PT_SR(r1) l.lwz r1,PT_SP(r1) /* Interrupts need to be disabled for setting EPCR and ESR * so that another interrupt doesn't come in here and clobber * them before we can use them for our l.rfe */ DISABLE_INTERRUPTS(r17,r19) l.mtspr r0,r13,SPR_EPCR_BASE l.mtspr r0,r15,SPR_ESR_BASE l.rfe /* End of hot path! * Keep the below tracing and error handling out of the hot path... */ _syscall_trace_enter: /* Here we pass pt_regs to do_syscall_trace_enter. Make sure * that function is really getting all the info it needs as * pt_regs isn't a complete set of userspace regs, just the * ones relevant to the syscall... * * Note use of delay slot for setting argument. */ l.jal do_syscall_trace_enter l.addi r3,r1,0 /* Restore arguments (not preserved across do_syscall_trace_enter) * so that we can do the syscall for real and return to the syscall * hot path. */ l.lwz r11,PT_GPR11(r1) l.lwz r3,PT_GPR3(r1) l.lwz r4,PT_GPR4(r1) l.lwz r5,PT_GPR5(r1) l.lwz r6,PT_GPR6(r1) l.lwz r7,PT_GPR7(r1) l.j _syscall_check l.lwz r8,PT_GPR8(r1) _syscall_trace_leave: l.jal do_syscall_trace_leave l.addi r3,r1,0 l.j _syscall_check_work l.nop _syscall_badsys: /* Here we effectively pretend to have executed an imaginary * syscall that returns -ENOSYS and then return to the regular * syscall hot path. * Note that "return value" is set in the delay slot... */ l.j _syscall_return l.addi r11,r0,-ENOSYS /******* END SYSCALL HANDLING *******/ /* ---[ 0xd00: Floating Point exception ]-------------------------------- */ EXCEPTION_ENTRY(_fpe_trap_handler) CLEAR_LWA_FLAG(r3) /* r4: EA of fault (set by EXCEPTION_HANDLE) */ l.jal do_fpe_trap l.addi r3,r1,0 /* pt_regs */ l.j _ret_from_exception l.nop /* ---[ 0xe00: Trap exception ]------------------------------------------ */ EXCEPTION_ENTRY(_trap_handler) CLEAR_LWA_FLAG(r3) /* r4: EA of fault (set by EXCEPTION_HANDLE) */ l.jal do_trap l.addi r3,r1,0 /* pt_regs */ l.j _ret_from_exception l.nop /* ---[ 0xf00: Reserved exception ]-------------------------------------- */ UNHANDLED_EXCEPTION(_vector_0xf00,0xf00) /* ---[ 0x1000: Reserved exception ]------------------------------------- */ UNHANDLED_EXCEPTION(_vector_0x1000,0x1000) /* ---[ 0x1100: Reserved exception ]------------------------------------- */ UNHANDLED_EXCEPTION(_vector_0x1100,0x1100) /* ---[ 0x1200: Reserved exception ]------------------------------------- */ UNHANDLED_EXCEPTION(_vector_0x1200,0x1200) /* ---[ 0x1300: Reserved exception ]------------------------------------- */ UNHANDLED_EXCEPTION(_vector_0x1300,0x1300) /* ---[ 0x1400: Reserved exception ]------------------------------------- */ UNHANDLED_EXCEPTION(_vector_0x1400,0x1400) /* ---[ 0x1500: Reserved exception ]------------------------------------- */ UNHANDLED_EXCEPTION(_vector_0x1500,0x1500) /* ---[ 0x1600: Reserved exception ]------------------------------------- */ UNHANDLED_EXCEPTION(_vector_0x1600,0x1600) /* ---[ 0x1700: Reserved exception ]------------------------------------- */ UNHANDLED_EXCEPTION(_vector_0x1700,0x1700) /* ---[ 0x1800: Reserved exception ]------------------------------------- */ UNHANDLED_EXCEPTION(_vector_0x1800,0x1800) /* ---[ 0x1900: Reserved exception ]------------------------------------- */ UNHANDLED_EXCEPTION(_vector_0x1900,0x1900) /* ---[ 0x1a00: Reserved exception ]------------------------------------- */ UNHANDLED_EXCEPTION(_vector_0x1a00,0x1a00) /* ---[ 0x1b00: Reserved exception ]------------------------------------- */ UNHANDLED_EXCEPTION(_vector_0x1b00,0x1b00) /* ---[ 0x1c00: Reserved exception ]------------------------------------- */ UNHANDLED_EXCEPTION(_vector_0x1c00,0x1c00) /* ---[ 0x1d00: Reserved exception ]------------------------------------- */ UNHANDLED_EXCEPTION(_vector_0x1d00,0x1d00) /* ---[ 0x1e00: Reserved exception ]------------------------------------- */ UNHANDLED_EXCEPTION(_vector_0x1e00,0x1e00) /* ---[ 0x1f00: Reserved exception ]------------------------------------- */ UNHANDLED_EXCEPTION(_vector_0x1f00,0x1f00) /* ========================================================[ return ] === */ _resume_userspace: DISABLE_INTERRUPTS(r3,r4) TRACE_IRQS_OFF l.lwz r4,TI_FLAGS(r10) l.andi r13,r4,_TIF_WORK_MASK l.sfeqi r13,0 l.bf _restore_all l.nop _work_pending: l.lwz r5,PT_ORIG_GPR11(r1) l.sfltsi r5,0 l.bnf 1f l.nop l.andi r5,r5,0 1: l.jal do_work_pending l.ori r3,r1,0 /* pt_regs */ l.sfeqi r11,0 l.bf _restore_all l.nop l.sfltsi r11,0 l.bnf 1f l.nop l.and r11,r11,r0 l.ori r11,r11,__NR_restart_syscall l.j _syscall_check_trace_enter l.nop 1: l.lwz r11,PT_ORIG_GPR11(r1) /* Restore arg registers */ l.lwz r3,PT_GPR3(r1) l.lwz r4,PT_GPR4(r1) l.lwz r5,PT_GPR5(r1) l.lwz r6,PT_GPR6(r1) l.lwz r7,PT_GPR7(r1) l.j _syscall_check_trace_enter l.lwz r8,PT_GPR8(r1) _restore_all: #ifdef CONFIG_TRACE_IRQFLAGS l.lwz r4,PT_SR(r1) l.andi r3,r4,(SPR_SR_IEE|SPR_SR_TEE) l.sfeq r3,r0 /* skip trace if irqs were off */ l.bf skip_hardirqs_on l.nop TRACE_IRQS_ON skip_hardirqs_on: #endif RESTORE_ALL /* This returns to userspace code */ ENTRY(_ret_from_intr) ENTRY(_ret_from_exception) l.lwz r4,PT_SR(r1) l.andi r3,r4,SPR_SR_SM l.sfeqi r3,0 l.bnf _restore_all l.nop l.j _resume_userspace l.nop ENTRY(ret_from_fork) l.jal schedule_tail l.nop /* Check if we are a kernel thread */ l.sfeqi r20,0 l.bf 1f l.nop /* ...we are a kernel thread so invoke the requested callback */ l.jalr r20 l.or r3,r22,r0 1: /* _syscall_returns expect r11 to contain return value */ l.lwz r11,PT_GPR11(r1) /* The syscall fast path return expects call-saved registers * r14-r28 to be untouched, so we restore them here as they * will have been effectively clobbered when arriving here * via the call to switch() */ l.lwz r14,PT_GPR14(r1) l.lwz r16,PT_GPR16(r1) l.lwz r18,PT_GPR18(r1) l.lwz r20,PT_GPR20(r1) l.lwz r22,PT_GPR22(r1) l.lwz r24,PT_GPR24(r1) l.lwz r26,PT_GPR26(r1) l.lwz r28,PT_GPR28(r1) l.j _syscall_return l.nop /* ========================================================[ switch ] === */ /* * This routine switches between two different tasks. The process * state of one is saved on its kernel stack. Then the state * of the other is restored from its kernel stack. The memory * management hardware is updated to the second process's state. * Finally, we can return to the second process, via the 'return'. * * Note: there are two ways to get to the "going out" portion * of this code; either by coming in via the entry (_switch) * or via "fork" which must set up an environment equivalent * to the "_switch" path. If you change this (or in particular, the * SAVE_REGS macro), you'll have to change the fork code also. */ /* _switch MUST never lay on page boundry, cause it runs from * effective addresses and beeing interrupted by iTLB miss would kill it. * dTLB miss seems to never accour in the bad place since data accesses * are from task structures which are always page aligned. * * The problem happens in RESTORE_ALL where we first set the EPCR * register, then load the previous register values and only at the end call * the l.rfe instruction. If get TLB miss in beetwen the EPCR register gets * garbled and we end up calling l.rfe with the wrong EPCR. (same probably * holds for ESR) * * To avoid this problems it is sufficient to align _switch to * some nice round number smaller than it's size... */ /* ABI rules apply here... we either enter _switch via schedule() or via * an imaginary call to which we shall return at return_from_fork. Either * way, we are a function call and only need to preserve the callee-saved * registers when we return. As such, we don't need to save the registers * on the stack that we won't be returning as they were... */ .align 0x400 ENTRY(_switch) /* We don't store SR as _switch only gets called in a context where * the SR will be the same going in and coming out... */ /* Set up new pt_regs struct for saving task state */ l.addi r1,r1,-(INT_FRAME_SIZE) /* No need to store r1/PT_SP as it goes into KSP below */ l.sw PT_GPR2(r1),r2 l.sw PT_GPR9(r1),r9 /* Save callee-saved registers to the new pt_regs */ l.sw PT_GPR14(r1),r14 l.sw PT_GPR16(r1),r16 l.sw PT_GPR18(r1),r18 l.sw PT_GPR20(r1),r20 l.sw PT_GPR22(r1),r22 l.sw PT_GPR24(r1),r24 l.sw PT_GPR26(r1),r26 l.sw PT_GPR28(r1),r28 l.sw PT_GPR30(r1),r30 l.addi r11,r10,0 /* Save old 'current' to 'last' return value*/ /* We use thread_info->ksp for storing the address of the above * structure so that we can get back to it later... we don't want * to lose the value of thread_info->ksp, though, so store it as * pt_regs->sp so that we can easily restore it when we are made * live again... */ /* Save the old value of thread_info->ksp as pt_regs->sp */ l.lwz r29,TI_KSP(r10) l.sw PT_SP(r1),r29 /* Swap kernel stack pointers */ l.sw TI_KSP(r10),r1 /* Save old stack pointer */ l.or r10,r4,r0 /* Set up new current_thread_info */ l.lwz r1,TI_KSP(r10) /* Load new stack pointer */ /* Restore the old value of thread_info->ksp */ l.lwz r29,PT_SP(r1) l.sw TI_KSP(r10),r29 /* ...and restore the registers, except r11 because the return value * has already been set above. */ l.lwz r2,PT_GPR2(r1) l.lwz r9,PT_GPR9(r1) /* No need to restore r10 */ /* ...and do not restore r11 */ /* Restore callee-saved registers */ l.lwz r14,PT_GPR14(r1) l.lwz r16,PT_GPR16(r1) l.lwz r18,PT_GPR18(r1) l.lwz r20,PT_GPR20(r1) l.lwz r22,PT_GPR22(r1) l.lwz r24,PT_GPR24(r1) l.lwz r26,PT_GPR26(r1) l.lwz r28,PT_GPR28(r1) l.lwz r30,PT_GPR30(r1) /* Unwind stack to pre-switch state */ l.addi r1,r1,(INT_FRAME_SIZE) /* Return via the link-register back to where we 'came from', where * that may be either schedule(), ret_from_fork(), or * ret_from_kernel_thread(). If we are returning to a new thread, * we are expected to have set up the arg to schedule_tail already, * hence we do so here unconditionally: */ l.lwz r3,TI_TASK(r3) /* Load 'prev' as schedule_tail arg */ l.jr r9 l.nop /* ==================================================================== */ /* These all use the delay slot for setting the argument register, so the * jump is always happening after the l.addi instruction. * * These are all just wrappers that don't touch the link-register r9, so the * return from the "real" syscall function will return back to the syscall * code that did the l.jal that brought us here. */ /* fork requires that we save all the callee-saved registers because they * are all effectively clobbered by the call to _switch. Here we store * all the registers that aren't touched by the syscall fast path and thus * weren't saved there. */ _fork_save_extra_regs_and_call: l.sw PT_GPR14(r1),r14 l.sw PT_GPR16(r1),r16 l.sw PT_GPR18(r1),r18 l.sw PT_GPR20(r1),r20 l.sw PT_GPR22(r1),r22 l.sw PT_GPR24(r1),r24 l.sw PT_GPR26(r1),r26 l.jr r29 l.sw PT_GPR28(r1),r28 ENTRY(__sys_clone) l.movhi r29,hi(sys_clone) l.j _fork_save_extra_regs_and_call l.ori r29,r29,lo(sys_clone) ENTRY(__sys_clone3) l.movhi r29,hi(sys_clone3) l.j _fork_save_extra_regs_and_call l.ori r29,r29,lo(sys_clone3) ENTRY(__sys_fork) l.movhi r29,hi(sys_fork) l.j _fork_save_extra_regs_and_call l.ori r29,r29,lo(sys_fork) ENTRY(sys_rt_sigreturn) l.jal _sys_rt_sigreturn l.addi r3,r1,0 l.sfne r30,r0 l.bnf _no_syscall_trace l.nop l.jal do_syscall_trace_leave l.addi r3,r1,0 _no_syscall_trace: l.j _resume_userspace l.nop /* This is a catch-all syscall for atomic instructions for the OpenRISC 1000. * The functions takes a variable number of parameters depending on which * particular flavour of atomic you want... parameter 1 is a flag identifying * the atomic in question. Currently, this function implements the * following variants: * * XCHG: * @flag: 1 * @ptr1: * @ptr2: * Atomically exchange the values in pointers 1 and 2. * */ ENTRY(sys_or1k_atomic) /* FIXME: This ignores r3 and always does an XCHG */ DISABLE_INTERRUPTS(r17,r19) l.lwz r29,0(r4) l.lwz r27,0(r5) l.sw 0(r4),r27 l.sw 0(r5),r29 ENABLE_INTERRUPTS(r17) l.jr r9 l.or r11,r0,r0 /* ============================================================[ EOF ]=== */
