/* switch.s * Machine dependent context switch routines. DO NOT MODIFY THESE! * * Context switching is inherently machine dependent, since * the registers to be saved, how to set up an initial * call frame, etc, are all specific to a processor architecture. * * This file currently supports the following architectures: * DEC MIPS * SUN SPARC * HP PA-RISC * Intel x86 (Linux + Solaris) * Mac OS X PowerPC * * We define two routines for each architecture: * * ThreadRoot(InitialPC, InitialArg, WhenDonePC, StartupPC) * InitialPC - The program counter of the procedure to run * in this thread. * InitialArg - The single argument to the thread. * WhenDonePC - The routine to call when the thread returns. * StartupPC - Routine to call when the thread is started. * * ThreadRoot is called from the SWITCH() routine to start * a thread for the first time. * * SWITCH(oldThread, newThread) * oldThread - The current thread that was running, where the * CPU register state is to be saved. * newThread - The new thread to be run, where the CPU register * state is to be loaded from. */ /* Copyright (c) 1992-1993 The Regents of the University of California. All rights reserved. See copyright.h for copyright notice and limitation of liability and disclaimer of warranty provisions. */ #include "copyright.h" #include "switch.h" #if defined(SOLARIS) || defined(MAC_OS) /* Those systems prepend a _ to symbol names */ #define ThreadRoot _ThreadRoot #define SWITCH _SWITCH #endif #ifdef HOST_MIPS /* Symbolic register names */ #define z $0 /* zero register */ #define a0 $4 /* argument registers */ #define a1 $5 #define s0 $16 /* callee saved */ #define s1 $17 #define s2 $18 #define s3 $19 #define s4 $20 #define s5 $21 #define s6 $22 #define s7 $23 #define sp $29 /* stack pointer */ #define fp $30 /* frame pointer */ #define ra $31 /* return address */ .text .align 2 .globl ThreadRoot .ent ThreadRoot,0 ThreadRoot: or fp,z,z # Clearing the frame pointer here # makes gdb backtraces of thread stacks # end here (I hope!) jal StartupPC # call startup procedure move a0, InitialArg jal InitialPC # call main procedure jal WhenDonePC # when we re done, call clean up procedure # NEVER REACHED .end ThreadRoot # a0 -- pointer to old Thread # a1 -- pointer to new Thread .globl SWITCH .ent SWITCH,0 SWITCH: sw sp, SP(a0) # save new stack pointer sw s0, S0(a0) # save all the callee-save registers sw s1, S1(a0) sw s2, S2(a0) sw s3, S3(a0) sw s4, S4(a0) sw s5, S5(a0) sw s6, S6(a0) sw s7, S7(a0) sw fp, FP(a0) # save frame pointer sw ra, PC(a0) # save return address lw sp, SP(a1) # load the new stack pointer lw s0, S0(a1) # load the callee-save registers lw s1, S1(a1) lw s2, S2(a1) lw s3, S3(a1) lw s4, S4(a1) lw s5, S5(a1) lw s6, S6(a1) lw s7, S7(a1) lw fp, FP(a1) lw ra, PC(a1) # load the return address j ra .end SWITCH #endif /* HOST_MIPS */ #ifdef HOST_SPARC /* NOTE! These files appear not to exist on Solaris -- * you need to find where (the SPARC-specific) MINFRAME, ST_FLUSH_WINDOWS, ... * are defined. (I don't have a Solaris machine, so I have no way to tell.) */ #ifndef SOLARIS #include #include #else #include #define MINFRAME 256 #define STACK_ALIGN 32L #endif .seg "text" /* SPECIAL to the SPARC: * The first two instruction of ThreadRoot are skipped because * the address of ThreadRoot is made the return address of SWITCH() * by the routine Thread::StackAllocate. SWITCH() jumps here on the * "ret" instruction which is really at "jmp %o7+8". The 8 skips the * two nops at the beginning of the routine. */ .globl ThreadRoot ThreadRoot: nop ; nop /* These 2 nops are skipped because we are called * with a jmp+8 instruction. */ clr %fp /* Clearing the frame pointer makes gdb backtraces * of thread stacks end here. */ /* Currently the arguments are in out registers we * save them into local registers so they won't be * trashed during the calls we make. */ mov InitialPC, %l0 mov InitialArg, %l1 mov WhenDonePC, %l2 /* Execute the code: * call StartupPC(); * call InitialPC(InitialArg); * call WhenDonePC(); */ call StartupPC,0 nop call %l0, 1 mov %l1, %o0 /* Using delay slot to setup argument to InitialPC */ call %l2, 0 nop /* WhenDonePC call should never return. If it does * we execute a trap into the debugger. */ ta ST_BREAKPOINT .globl SWITCH SWITCH: save %sp, -MINFRAME, %sp st %fp, [%i0] st %i0, [%i0+I0] st %i1, [%i0+I1] st %i2, [%i0+I2] st %i3, [%i0+I3] st %i4, [%i0+I4] st %i5, [%i0+I5] st %i7, [%i0+I7] ta ST_FLUSH_WINDOWS nop mov %i1, %l0 ld [%l0+I0], %i0 ld [%l0+I1], %i1 ld [%l0+I2], %i2 ld [%l0+I3], %i3 ld [%l0+I4], %i4 ld [%l0+I5], %i5 ld [%l0+I7], %i7 ld [%l0], %i6 ret restore #endif /* HOST_SPARC */ #ifdef HOST_PPC .globl ThreadRoot ThreadRoot: mr r30, r1 stw r5, 128(r1) stw r6, 132(r1) stw r7, 136(r1) #Call startupPC mtctr r8 bctrl mr r2, r31 # Call InitialPC with InitialArg lwz r3, 132(r1) lwz r5, 128(r1) mtctr r5 bctrl # Call WhenDonePC lwz r7, 136(r1) mtctr r7 bctrl mr r31, r2 .globl SWITCH SWITCH: mflr r0 stw r0,4(r3) stw r1,0(r3) stw r2,8(r3) stw r3,12(r3) stw r5,20(r3) stw r6,24(r3) stw r7,28(r3) stw r8,32(r3) stw r9,36(r3) stw r10,40(r3) stw r11,44(r3) stw r12,48(r3) stw r13,52(r3) stw r14,56(r3) stw r15,60(r3) stw r16,64(r3) stw r17,68(r3) stw r18,72(r3) stw r19,76(r3) stw r20,80(r3) stw r21,84(r3) stw r22,88(r3) stw r23,92(r3) stw r24,96(r3) stw r25,100(r3) stw r26,104(r3) stw r27,108(r3) stw r28,112(r3) stw r29,116(r3) stw r30,120(r3) stw r31,124(r3) lwz r0,4(r4) lwz r1,0(r4) lwz r2,8(r4) lwz r3,12(r4) lwz r5,20(r4) lwz r6,24(r4) lwz r7,28(r4) lwz r8,32(r4) lwz r9,36(r4) lwz r10,40(r4) lwz r11,44(r4) lwz r12,48(r4) lwz r13,52(r4) lwz r14,56(r4) lwz r15,60(r4) lwz r16,64(r4) lwz r17,68(r4) lwz r18,72(r4) lwz r19,76(r4) lwz r20,80(r4) lwz r21,84(r4) lwz r22,88(r4) lwz r23,92(r4) lwz r24,96(r4) lwz r25,100(r4) lwz r26,104(r4) lwz r27,108(r4) lwz r28,112(r4) lwz r29,116(r4) lwz r30,120(r4) lwz r31,124(r4) mtlr r0 blr #endif /* HOST_PPC */ #ifdef HOST_SNAKE ;rp = r2, sp = r30 ;arg0 = r26, arg1 = r25, arg2 = r24, arg3 = r23 .SPACE $TEXT$ .SUBSPA $CODE$ ThreadRoot .PROC .CALLINFO CALLER,FRAME=0 .ENTRY .CALL ble 0(%r6) ;call StartupPC or %r31, 0, %rp ;put return address in proper register or %r4, 0, %arg0 ;load InitialArg .CALL ;in=26 ble 0(%r3) ;call InitialPC or %r31, 0, %rp ;put return address in proper register .CALL ble 0(%r5) ;call WhenDonePC .EXIT or %r31, 0, %rp ;shouldn't really matter - doesn't return .PROCEND SWITCH .PROC .CALLINFO CALLER,FRAME=0 .ENTRY ; save process state of oldThread stw %sp, SP(%arg0) ;save stack pointer stw %r3, S0(%arg0) ;save callee-save registers stw %r4, S1(%arg0) stw %r5, S2(%arg0) stw %r6, S3(%arg0) stw %r7, S4(%arg0) stw %r8, S5(%arg0) stw %r9, S6(%arg0) stw %r10, S7(%arg0) stw %r11, S8(%arg0) stw %r12, S9(%arg0) stw %r13, S10(%arg0) stw %r14, S11(%arg0) stw %r15, S12(%arg0) stw %r16, S13(%arg0) stw %r17, S14(%arg0) stw %r18, S15(%arg0) stw %rp, PC(%arg0) ;save program counter ; restore process state of nextThread ldw SP(%arg1), %sp ;restore stack pointer ldw S0(%arg1), %r3 ;restore callee-save registers ldw S1(%arg1), %r4 ldw S2(%arg1), %r5 ldw S3(%arg1), %r6 ldw S4(%arg1), %r7 ldw S5(%arg1), %r8 ldw S6(%arg1), %r9 ldw S7(%arg1), %r10 ldw S8(%arg1), %r11 ldw S9(%arg1), %r12 ldw S10(%arg1), %r13 ldw S11(%arg1), %r14 ldw S12(%arg1), %r15 ldw S13(%arg1), %r16 ldw S14(%arg1), %r17 ldw PC(%arg1), %rp ;save program counter bv 0(%rp) .EXIT ldw S15(%arg1), %r18 .PROCEND .EXPORT SWITCH,ENTRY,PRIV_LEV=3,RTNVAL=GR .EXPORT ThreadRoot,ENTRY,PRIV_LEV=3,RTNVAL=GR #endif #ifdef HOST_i386 .text .align 2 /* void ThreadRoot( void ) ** ** expects the following registers to be initialized: ** eax points to startup function (interrupt enable) ** edx contains inital argument to thread function ** esi points to thread function ** edi point to Thread::Finish() */ .globl ThreadRoot ThreadRoot: .cfi_startproc .cfi_undefined rip xorl %ebp,%ebp pushl InitialArg call *StartupPC call *InitialPC call *WhenDonePC /* NOT REACHED*/ movl %ebp,%esp popl %ebp ret .cfi_endproc /* void SWITCH( thread *t1, thread *t2 ) ** ** on entry, stack looks like this: ** 8(esp) -> thread *t2 ** 4(esp) -> thread *t1 ** (esp) -> return address ** ** we push the current eax on the stack so that we can use it as ** a pointer to t1, this decrements esp by 4, so when we use it ** to reference stuff on the stack, we add 4 to the offset. */ .comm _eax_save,4 .globl SWITCH SWITCH: movl %eax,_eax_save /* save the value of eax */ movl 4(%esp),%eax /* move pointer to t1 into eax */ movl %ebx,_EBX(%eax) /* save registers */ movl %ecx,_ECX(%eax) movl %edx,_EDX(%eax) movl %esi,_ESI(%eax) movl %edi,_EDI(%eax) movl %ebp,_EBP(%eax) movl %esp,_ESP(%eax) /* save stack pointer */ movl _eax_save,%ebx /* get the saved value of eax */ movl %ebx,_EAX(%eax) /* store it */ movl 0(%esp),%ebx /* get return address from stack into ebx */ movl %ebx,_PC(%eax) /* save it into the pc storage */ movl 8(%esp),%eax /* move pointer to t2 into eax */ movl _EAX(%eax),%ebx /* get new value for eax into ebx */ movl %ebx,_eax_save /* save it */ movl _EBX(%eax),%ebx /* retore old registers */ movl _ECX(%eax),%ecx movl _EDX(%eax),%edx movl _ESI(%eax),%esi movl _EDI(%eax),%edi movl _EBP(%eax),%ebp movl _ESP(%eax),%esp /* restore stack pointer */ movl _PC(%eax),%eax /* restore return address into eax */ movl %eax,0(%esp) /* copy over the ret address on the stack */ movl _eax_save,%eax ret #endif #ifdef HOST_x86_64 .text .align 2 /* void ThreadRoot( void ) ** ** expects the following registers to be initialized: ** rcx points to startup function (interrupt enable) ** rdx contains inital argument to thread function ** rsi points to thread function ** rdi point to Thread::Finish() */ .globl ThreadRoot ThreadRoot: .cfi_startproc .cfi_undefined rip xorq %rbp,%rbp subq $8,%rsp /* Alignment for SSE */ pushq WhenDonePC pushq InitialPC pushq InitialArg call *StartupPC movq (%rsp),%rdi movq 8(%rsp),InitialPC call *InitialPC movq 16(%rsp),WhenDonePC call *WhenDonePC /* NOT REACHED*/ popq InitialArg popq InitialPC popq WhenDonePC addq $8, %rsp movq %rbp,%rsp popq %rbp ret .cfi_endproc /* void SWITCH( thread *t1, thread *t2 ) ** ** on entry, stack looks like this: ** (rsp) -> return address ** ** rdi contains thread *t1 ** rsi contains thread *t2 ** ** we push the current rax on the stack so that we can use it as ** a pointer to t1, this decrements rsp by 8, so when we use it ** to reference stuff on the stack, we add 8 to the offset. */ .comm _rax_save,8 .globl SWITCH SWITCH: movq %rax,_rax_save(%rip) /* save the value of rax */ movq %rdi,%rax /* move pointer to t1 into rax */ movq %rbx,_RBX(%rax) /* save registers */ movq %rcx,_RCX(%rax) movq %rdx,_RDX(%rax) movq %rsi,_RSI(%rax) movq %rdi,_RDI(%rax) movq %r12,_R12(%rax) movq %r13,_R13(%rax) movq %r14,_R14(%rax) movq %r15,_R15(%rax) movq %rbp,_RBP(%rax) movq %rsp,_RSP(%rax) /* save stack pointer */ movq _rax_save(%rip),%rbx /* get the saved value of rax */ movq %rbx,_RAX(%rax) /* store it */ movq 0(%rsp),%rbx /* get return address from stack into rbx */ movq %rbx,_PC(%rax) /* save it into the pc storage */ movq %rsi,%rax /* move pointer to t2 into rax */ movq _RAX(%rax),%rbx /* get new value for rax into rbx */ movq %rbx,_rax_save(%rip) /* save it */ movq _RBX(%rax),%rbx /* retore old registers */ movq _RCX(%rax),%rcx movq _RDX(%rax),%rdx movq _RSI(%rax),%rsi movq _RDI(%rax),%rdi movq _R12(%rax),%r12 movq _R13(%rax),%r13 movq _R14(%rax),%r14 movq _R15(%rax),%r15 movq _RBP(%rax),%rbp movq _RSP(%rax),%rsp /* restore stack pointer */ movq _PC(%rax),%rax /* restore return address into rax */ movq %rax,0(%rsp) /* copy over the ret address on the stack */ movq _rax_save(%rip),%rax ret #endif