/* * Copyright (c) 2000 Apple Computer, Inc. All rights reserved. * * @APPLE_LICENSE_HEADER_START@ * * Copyright (c) 1999-2003 Apple Computer, Inc. All Rights Reserved. * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this * file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_LICENSE_HEADER_END@ */ /* * @OSF_COPYRIGHT@ */ /* * Mach Operating System * Copyright (c) 1991,1990 Carnegie Mellon University * All Rights Reserved. * * Permission to use, copy, modify and distribute this software and its * documentation is hereby granted, provided that both the copyright * notice and this permission notice appear in all copies of the * software, derivative works or modified versions, and any portions * thereof, and that both notices appear in supporting documentation. * * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. * * Carnegie Mellon requests users of this software to return to * * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU * School of Computer Science * Carnegie Mellon University * Pittsburgh PA 15213-3890 * * any improvements or extensions that they make and grant Carnegie Mellon * the rights to redistribute these changes. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define PREEMPT_DEBUG_LOG 0 #if __MACHO__ /* Under Mach-O, etext is a variable which contains * the last text address */ #define ETEXT_ADDR (EXT(etext)) #else /* Under ELF and other non-Mach-O formats, the address of * etext represents the last text address */ #define ETEXT_ADDR $ EXT(etext) #endif #if NCPUS > 1 #define CX(addr,reg) addr(,reg,4) #else #define CPU_NUMBER(reg) #define CX(addr,reg) addr #endif /* NCPUS > 1 */ .text locore_start: /* * Fault recovery. */ #ifdef __MACHO__ #define RECOVERY_SECTION .section __VECTORS, __recover #define RETRY_SECTION .section __VECTORS, __retries #else #define RECOVERY_SECTION .text #define RECOVERY_SECTION .text #endif #define RECOVER_TABLE_START \ .align 2 ; \ .globl EXT(recover_table) ;\ LEXT(recover_table) ;\ .text #define RECOVER(addr) \ .align 2; \ .long 9f ;\ .long addr ;\ .text ;\ 9: #define RECOVER_TABLE_END \ .align 2 ;\ .globl EXT(recover_table_end) ;\ LEXT(recover_table_end) ;\ .text /* * Retry table for certain successful faults. */ #define RETRY_TABLE_START \ .align 3; \ .globl EXT(retry_table) ;\ LEXT(retry_table) ;\ .text #define RETRY(addr) \ .align 3 ;\ .long 9f ;\ .long addr ;\ .text ;\ 9: #define RETRY_TABLE_END \ .align 3; \ .globl EXT(retry_table_end) ;\ LEXT(retry_table_end) ;\ .text /* * Allocate recovery and retry tables. */ RECOVERY_SECTION RECOVER_TABLE_START RETRY_SECTION RETRY_TABLE_START /* * Timing routines. */ #if STAT_TIME #define TIME_TRAP_UENTRY #define TIME_TRAP_UEXIT #define TIME_INT_ENTRY #define TIME_INT_EXIT #else /* microsecond timing */ /* * Microsecond timing. * Assumes a free-running microsecond counter. * no TIMER_MAX check needed. */ /* * There is only one current time-stamp per CPU, since only * the time-stamp in the current timer is used. * To save time, we allocate the current time-stamps here. */ .comm EXT(current_tstamp), 4*NCPUS /* * Update time on user trap entry. * 11 instructions (including cli on entry) * Assumes CPU number in %edx. * Uses %ebx, %ecx. */ #define TIME_TRAP_UENTRY \ cli /* block interrupts */ ;\ movl VA_ETC,%ebx /* get timer value */ ;\ movl CX(EXT(current_tstamp),%edx),%ecx /* get old time stamp */;\ movl %ebx,CX(EXT(current_tstamp),%edx) /* set new time stamp */;\ subl %ecx,%ebx /* elapsed = new-old */ ;\ movl CX(EXT(current_timer),%edx),%ecx /* get current timer */;\ addl %ebx,LOW_BITS(%ecx) /* add to low bits */ ;\ jns 0f /* if overflow, */ ;\ call timer_normalize /* normalize timer */ ;\ 0: addl $(TH_SYS_TIMER-TH_USER_TIMER),%ecx ;\ /* switch to sys timer */;\ movl %ecx,CX(EXT(current_timer),%edx) /* make it current */ ;\ sti /* allow interrupts */ /* * update time on user trap exit. * 10 instructions. * Assumes CPU number in %edx. * Uses %ebx, %ecx. */ #define TIME_TRAP_UEXIT \ cli /* block interrupts */ ;\ movl VA_ETC,%ebx /* get timer */ ;\ movl CX(EXT(current_tstamp),%edx),%ecx /* get old time stamp */;\ movl %ebx,CX(EXT(current_tstamp),%edx) /* set new time stamp */;\ subl %ecx,%ebx /* elapsed = new-old */ ;\ movl CX(EXT(current_timer),%edx),%ecx /* get current timer */;\ addl %ebx,LOW_BITS(%ecx) /* add to low bits */ ;\ jns 0f /* if overflow, */ ;\ call timer_normalize /* normalize timer */ ;\ 0: addl $(TH_USER_TIMER-TH_SYS_TIMER),%ecx ;\ /* switch to user timer */;\ movl %ecx,CX(EXT(current_timer),%edx) /* make it current */ /* * update time on interrupt entry. * 9 instructions. * Assumes CPU number in %edx. * Leaves old timer in %ebx. * Uses %ecx. */ #define TIME_INT_ENTRY \ movl VA_ETC,%ecx /* get timer */ ;\ movl CX(EXT(current_tstamp),%edx),%ebx /* get old time stamp */;\ movl %ecx,CX(EXT(current_tstamp),%edx) /* set new time stamp */;\ subl %ebx,%ecx /* elapsed = new-old */ ;\ movl CX(EXT(current_timer),%edx),%ebx /* get current timer */;\ addl %ecx,LOW_BITS(%ebx) /* add to low bits */ ;\ leal CX(0,%edx),%ecx /* timer is 16 bytes */ ;\ lea CX(EXT(kernel_timer),%edx),%ecx /* get interrupt timer*/;\ movl %ecx,CX(EXT(current_timer),%edx) /* set timer */ /* * update time on interrupt exit. * 11 instructions * Assumes CPU number in %edx, old timer in %ebx. * Uses %eax, %ecx. */ #define TIME_INT_EXIT \ movl VA_ETC,%eax /* get timer */ ;\ movl CX(EXT(current_tstamp),%edx),%ecx /* get old time stamp */;\ movl %eax,CX(EXT(current_tstamp),%edx) /* set new time stamp */;\ subl %ecx,%eax /* elapsed = new-old */ ;\ movl CX(EXT(current_timer),%edx),%ecx /* get current timer */;\ addl %eax,LOW_BITS(%ecx) /* add to low bits */ ;\ jns 0f /* if overflow, */ ;\ call timer_normalize /* normalize timer */ ;\ 0: testb $0x80,LOW_BITS+3(%ebx) /* old timer overflow? */;\ jz 0f /* if overflow, */ ;\ movl %ebx,%ecx /* get old timer */ ;\ call timer_normalize /* normalize timer */ ;\ 0: movl %ebx,CX(EXT(current_timer),%edx) /* set timer */ /* * Normalize timer in ecx. * Preserves edx; clobbers eax. */ .align ALIGN timer_high_unit: .long TIMER_HIGH_UNIT /* div has no immediate opnd */ timer_normalize: pushl %edx /* save registersz */ pushl %eax xorl %edx,%edx /* clear divisor high */ movl LOW_BITS(%ecx),%eax /* get divisor low */ divl timer_high_unit,%eax /* quotient in eax */ /* remainder in edx */ addl %eax,HIGH_BITS_CHECK(%ecx) /* add high_inc to check */ movl %edx,LOW_BITS(%ecx) /* remainder to low_bits */ addl %eax,HIGH_BITS(%ecx) /* add high_inc to high bits */ popl %eax /* restore register */ popl %edx ret /* * Switch to a new timer. */ Entry(timer_switch) CPU_NUMBER(%edx) /* get this CPU */ movl VA_ETC,%ecx /* get timer */ movl CX(EXT(current_tstamp),%edx),%eax /* get old time stamp */ movl %ecx,CX(EXT(current_tstamp),%edx) /* set new time stamp */ subl %ecx,%eax /* elapsed = new - old */ movl CX(EXT(current_timer),%edx),%ecx /* get current timer */ addl %eax,LOW_BITS(%ecx) /* add to low bits */ jns 0f /* if overflow, */ call timer_normalize /* normalize timer */ 0: movl S_ARG0,%ecx /* get new timer */ movl %ecx,CX(EXT(current_timer),%edx) /* set timer */ ret /* * Initialize the first timer for a CPU. */ Entry(start_timer) CPU_NUMBER(%edx) /* get this CPU */ movl VA_ETC,%ecx /* get timer */ movl %ecx,CX(EXT(current_tstamp),%edx) /* set initial time stamp */ movl S_ARG0,%ecx /* get timer */ movl %ecx,CX(EXT(current_timer),%edx) /* set initial timer */ ret #endif /* accurate timing */ /* * Encapsulate the transfer of exception stack frames between a PCB * and a thread stack. Since the whole point of these is to emulate * a call or exception that changes privilege level, both macros * assume that there is no user esp or ss stored in the source * frame (because there was no change of privilege to generate them). */ /* * Transfer a stack frame from a thread's user stack to its PCB. * We assume the thread and stack addresses have been loaded into * registers (our arguments). * * The macro overwrites edi, esi, ecx and whatever registers hold the * thread and stack addresses (which can't be one of the above three). * The thread address is overwritten with the address of its saved state * (where the frame winds up). * * Must be called on kernel stack. */ #define FRAME_STACK_TO_PCB(thread, stkp) ;\ movl ACT_PCB(thread),thread /* get act`s PCB */ ;\ leal PCB_ISS(thread),%edi /* point to PCB`s saved state */;\ movl %edi,thread /* save for later */ ;\ movl stkp,%esi /* point to start of frame */ ;\ movl $ R_UESP,%ecx ;\ sarl $2,%ecx /* word count for transfer */ ;\ cld /* we`re incrementing */ ;\ rep ;\ movsl /* transfer the frame */ ;\ addl $ R_UESP,stkp /* derive true "user" esp */ ;\ movl stkp,R_UESP(thread) /* store in PCB */ ;\ movl $0,%ecx ;\ mov %ss,%cx /* get current ss */ ;\ movl %ecx,R_SS(thread) /* store in PCB */ /* * Transfer a stack frame from a thread's PCB to the stack pointed * to by the PCB. We assume the thread address has been loaded into * a register (our argument). * * The macro overwrites edi, esi, ecx and whatever register holds the * thread address (which can't be one of the above three). The * thread address is overwritten with the address of its saved state * (where the frame winds up). * * Must be called on kernel stack. */ #define FRAME_PCB_TO_STACK(thread) ;\ movl ACT_PCB(thread),%esi /* get act`s PCB */ ;\ leal PCB_ISS(%esi),%esi /* point to PCB`s saved state */;\ movl R_UESP(%esi),%edi /* point to end of dest frame */;\ movl ACT_MAP(thread),%ecx /* get act's map */ ;\ movl MAP_PMAP(%ecx),%ecx /* get map's pmap */ ;\ cmpl EXT(kernel_pmap), %ecx /* If kernel loaded task */ ;\ jz 1f /* use kernel data segment */ ;\ movl $ USER_DS,%cx /* else use user data segment */;\ mov %cx,%es ;\ 1: ;\ movl $ R_UESP,%ecx ;\ subl %ecx,%edi /* derive start of frame */ ;\ movl %edi,thread /* save for later */ ;\ sarl $2,%ecx /* word count for transfer */ ;\ cld /* we`re incrementing */ ;\ rep ;\ movsl /* transfer the frame */ ;\ mov %ss,%cx /* restore kernel segments */ ;\ mov %cx,%es #undef PDEBUG #ifdef PDEBUG /* * Traditional, not ANSI. */ #define CAH(label) \ .data ;\ .globl label/**/count ;\ label/**/count: ;\ .long 0 ;\ .globl label/**/limit ;\ label/**/limit: ;\ .long 0 ;\ .text ;\ addl $1,%ss:label/**/count ;\ cmpl $0,label/**/limit ;\ jz label/**/exit ;\ pushl %eax ;\ label/**/loop: ;\ movl %ss:label/**/count,%eax ;\ cmpl %eax,%ss:label/**/limit ;\ je label/**/loop ;\ popl %eax ;\ label/**/exit: #else /* PDEBUG */ #define CAH(label) #endif /* PDEBUG */ #if MACH_KDB /* * Last-ditch debug code to handle faults that might result * from entering kernel (from collocated server) on an invalid * stack. On collocated entry, there's no hardware-initiated * stack switch, so a valid stack must be in place when an * exception occurs, or we may double-fault. * * In case of a double-fault, our only recourse is to switch * hardware "tasks", so that we avoid using the current stack. * * The idea here is just to get the processor into the debugger, * post-haste. No attempt is made to fix up whatever error got * us here, so presumably continuing from the debugger will * simply land us here again -- at best. */ #if 0 /* * Note that the per-fault entry points are not currently * functional. The only way to make them work would be to * set up separate TSS's for each fault type, which doesn't * currently seem worthwhile. (The offset part of a task * gate is always ignored.) So all faults that task switch * currently resume at db_task_start. */ /* * Double fault (Murphy's point) - error code (0) on stack */ Entry(db_task_dbl_fault) popl %eax movl $(T_DOUBLE_FAULT),%ebx jmp db_task_start /* * Segment not present - error code on stack */ Entry(db_task_seg_np) popl %eax movl $(T_SEGMENT_NOT_PRESENT),%ebx jmp db_task_start /* * Stack fault - error code on (current) stack */ Entry(db_task_stk_fault) popl %eax movl $(T_STACK_FAULT),%ebx jmp db_task_start /* * General protection fault - error code on stack */ Entry(db_task_gen_prot) popl %eax movl $(T_GENERAL_PROTECTION),%ebx jmp db_task_start #endif /* 0 */ /* * The entry point where execution resumes after last-ditch debugger task * switch. */ Entry(db_task_start) movl %esp,%edx subl $ISS_SIZE,%edx movl %edx,%esp /* allocate i386_saved_state on stack */ movl %eax,R_ERR(%esp) movl %ebx,R_TRAPNO(%esp) pushl %edx #if NCPUS > 1 CPU_NUMBER(%edx) movl CX(EXT(mp_dbtss),%edx),%edx movl TSS_LINK(%edx),%eax #else movl EXT(dbtss)+TSS_LINK,%eax #endif pushl %eax /* pass along selector of previous TSS */ call EXT(db_tss_to_frame) popl %eax /* get rid of TSS selector */ call EXT(db_trap_from_asm) addl $0x4,%esp /* * And now...? */ iret /* ha, ha, ha... */ #endif /* MACH_KDB */ /* * Trap/interrupt entry points. * * All traps must create the following save area on the PCB "stack": * * gs * fs * es * ds * edi * esi * ebp * cr2 if page fault - otherwise unused * ebx * edx * ecx * eax * trap number * error code * eip * cs * eflags * user esp - if from user * user ss - if from user * es - if from V86 thread * ds - if from V86 thread * fs - if from V86 thread * gs - if from V86 thread * */ /* * General protection or segment-not-present fault. * Check for a GP/NP fault in the kernel_return * sequence; if there, report it as a GP/NP fault on the user's instruction. * * esp-> 0: trap code (NP or GP) * 4: segment number in error * 8 eip * 12 cs * 16 eflags * 20 old registers (trap is from kernel) */ Entry(t_gen_prot) pushl $(T_GENERAL_PROTECTION) /* indicate fault type */ jmp trap_check_kernel_exit /* check for kernel exit sequence */ Entry(t_segnp) pushl $(T_SEGMENT_NOT_PRESENT) /* indicate fault type */ trap_check_kernel_exit: testl $(EFL_VM),16(%esp) /* is trap from V86 mode? */ jnz EXT(alltraps) /* isn`t kernel trap if so */ testl $3,12(%esp) /* is trap from kernel mode? */ jne EXT(alltraps) /* if so: */ /* check for the kernel exit sequence */ cmpl $ EXT(kret_iret),8(%esp) /* on IRET? */ je fault_iret cmpl $ EXT(kret_popl_ds),8(%esp) /* popping DS? */ je fault_popl_ds cmpl $ EXT(kret_popl_es),8(%esp) /* popping ES? */ je fault_popl_es cmpl $ EXT(kret_popl_fs),8(%esp) /* popping FS? */ je fault_popl_fs cmpl $ EXT(kret_popl_gs),8(%esp) /* popping GS? */ je fault_popl_gs take_fault: /* if none of the above: */ jmp EXT(alltraps) /* treat as normal trap. */ /* * GP/NP fault on IRET: CS or SS is in error. * All registers contain the user's values. * * on SP is * 0 trap number * 4 errcode * 8 eip * 12 cs --> trapno * 16 efl --> errcode * 20 user eip * 24 user cs * 28 user eflags * 32 user esp * 36 user ss */ fault_iret: movl %eax,8(%esp) /* save eax (we don`t need saved eip) */ popl %eax /* get trap number */ movl %eax,12-4(%esp) /* put in user trap number */ popl %eax /* get error code */ movl %eax,16-8(%esp) /* put in user errcode */ popl %eax /* restore eax */ CAH(fltir) jmp EXT(alltraps) /* take fault */ /* * Fault restoring a segment register. The user's registers are still * saved on the stack. The offending segment register has not been * popped. */ fault_popl_ds: popl %eax /* get trap number */ popl %edx /* get error code */ addl $12,%esp /* pop stack to user regs */ jmp push_es /* (DS on top of stack) */ fault_popl_es: popl %eax /* get trap number */ popl %edx /* get error code */ addl $12,%esp /* pop stack to user regs */ jmp push_fs /* (ES on top of stack) */ fault_popl_fs: popl %eax /* get trap number */ popl %edx /* get error code */ addl $12,%esp /* pop stack to user regs */ jmp push_gs /* (FS on top of stack) */ fault_popl_gs: popl %eax /* get trap number */ popl %edx /* get error code */ addl $12,%esp /* pop stack to user regs */ jmp push_segregs /* (GS on top of stack) */ push_es: pushl %es /* restore es, */ push_fs: pushl %fs /* restore fs, */ push_gs: pushl %gs /* restore gs. */ push_segregs: movl %eax,R_TRAPNO(%esp) /* set trap number */ movl %edx,R_ERR(%esp) /* set error code */ CAH(fltpp) jmp trap_set_segs /* take trap */ /* * Debug trap. Check for single-stepping across system call into * kernel. If this is the case, taking the debug trap has turned * off single-stepping - save the flags register with the trace * bit set. */ Entry(t_debug) testl $(EFL_VM),8(%esp) /* is trap from V86 mode? */ jnz 0f /* isn`t kernel trap if so */ testl $3,4(%esp) /* is trap from kernel mode? */ jnz 0f /* if so: */ cmpl $syscall_entry,(%esp) /* system call entry? */ jne 1f /* if so: */ /* flags are sitting where syscall */ /* wants them */ addl $8,%esp /* remove eip/cs */ jmp syscall_entry_2 /* continue system call entry */ 1: cmpl $trap_unix_addr,(%esp) jne 0f addl $8,%esp jmp trap_unix_2 0: pushl $0 /* otherwise: */ pushl $(T_DEBUG) /* handle as normal */ jmp EXT(alltraps) /* debug fault */ /* * Page fault traps save cr2. */ Entry(t_page_fault) pushl $(T_PAGE_FAULT) /* mark a page fault trap */ pusha /* save the general registers */ movl %cr2,%eax /* get the faulting address */ movl %eax,12(%esp) /* save in esp save slot */ jmp trap_push_segs /* continue fault */ /* * All 'exceptions' enter here with: * esp-> trap number * error code * old eip * old cs * old eflags * old esp if trapped from user * old ss if trapped from user * * NB: below use of CPU_NUMBER assumes that macro will use correct * segment register for any kernel data accesses. */ Entry(alltraps) pusha /* save the general registers */ trap_push_segs: pushl %ds /* save the segment registers */ pushl %es pushl %fs pushl %gs trap_set_segs: movl %ss,%ax movl %ax,%ds movl %ax,%es /* switch to kernel data seg */ cld /* clear direction flag */ testl $(EFL_VM),R_EFLAGS(%esp) /* in V86 mode? */ jnz trap_from_user /* user mode trap if so */ testb $3,R_CS(%esp) /* user mode trap? */ jnz trap_from_user CPU_NUMBER(%edx) cmpl $0,CX(EXT(active_kloaded),%edx) je trap_from_kernel /* if clear, truly in kernel */ #ifdef FIXME cmpl ETEXT_ADDR,R_EIP(%esp) /* pc within kernel? */ jb trap_from_kernel #endif trap_from_kloaded: /* * We didn't enter here "through" PCB (i.e., using ring 0 stack), * so transfer the stack frame into the PCB explicitly, then * start running on resulting "PCB stack". We have to set * up a simulated "uesp" manually, since there's none in the * frame. */ mov $ CPU_DATA,%dx mov %dx,%gs CAH(atstart) CPU_NUMBER(%edx) movl CX(EXT(active_kloaded),%edx),%ebx movl CX(EXT(kernel_stack),%edx),%eax xchgl %esp,%eax FRAME_STACK_TO_PCB(%ebx,%eax) CAH(atend) jmp EXT(take_trap) trap_from_user: mov $ CPU_DATA,%ax mov %ax,%gs CPU_NUMBER(%edx) TIME_TRAP_UENTRY movl CX(EXT(kernel_stack),%edx),%ebx xchgl %ebx,%esp /* switch to kernel stack */ /* user regs pointer already set */ LEXT(take_trap) pushl %ebx /* record register save area */ pushl %ebx /* pass register save area to trap */ call EXT(user_trap) /* call user trap routine */ movl 4(%esp),%esp /* switch back to PCB stack */ /* * Return from trap or system call, checking for ASTs. * On PCB stack. */ LEXT(return_from_trap) CPU_NUMBER(%edx) cmpl $0,CX(EXT(need_ast),%edx) je EXT(return_to_user) /* if we need an AST: */ movl CX(EXT(kernel_stack),%edx),%esp /* switch to kernel stack */ pushl $0 /* push preemption flag */ call EXT(i386_astintr) /* take the AST */ addl $4,%esp /* pop preemption flag */ popl %esp /* switch back to PCB stack (w/exc link) */ jmp EXT(return_from_trap) /* and check again (rare) */ /* ASTs after this point will */ /* have to wait */ /* * Arrange the checks needed for kernel-loaded (or kernel-loading) * threads so that branch is taken in kernel-loaded case. */ LEXT(return_to_user) TIME_TRAP_UEXIT CPU_NUMBER(%eax) cmpl $0,CX(EXT(active_kloaded),%eax) jnz EXT(return_xfer_stack) movl $ CPD_ACTIVE_THREAD,%ebx movl %gs:(%ebx),%ebx /* get active thread */ #if MACH_RT #if MACH_ASSERT movl $ CPD_PREEMPTION_LEVEL,%ebx cmpl $0,%gs:(%ebx) je EXT(return_from_kernel) int $3 #endif /* MACH_ASSERT */ #endif /* MACH_RT */ /* * Return from kernel mode to interrupted thread. */ LEXT(return_from_kernel) LEXT(kret_popl_gs) popl %gs /* restore segment registers */ LEXT(kret_popl_fs) popl %fs LEXT(kret_popl_es) popl %es LEXT(kret_popl_ds) popl %ds popa /* restore general registers */ addl $8,%esp /* discard trap number and error code */ LEXT(kret_iret) iret /* return from interrupt */ LEXT(return_xfer_stack) /* * If we're on PCB stack in a kernel-loaded task, we have * to transfer saved state back to thread stack and swap * stack pointers here, because the hardware's not going * to do so for us. */ CAH(rxsstart) CPU_NUMBER(%eax) movl CX(EXT(kernel_stack),%eax),%esp movl CX(EXT(active_kloaded),%eax),%eax FRAME_PCB_TO_STACK(%eax) movl %eax,%esp CAH(rxsend) jmp EXT(return_from_kernel) /* * Hate to put this here, but setting up a separate swap_func for * kernel-loaded threads no longer works, since thread executes * "for a while" (i.e., until it reaches glue code) when first * created, even if it's nominally suspended. Hence we can't * transfer the PCB when the thread first resumes, because we * haven't initialized it yet. */ /* * Have to force transfer to new stack "manually". Use a string * move to transfer all of our saved state to the stack pointed * to by iss.uesp, then install a pointer to it as our current * stack pointer. */ LEXT(return_kernel_loading) CPU_NUMBER(%eax) movl CX(EXT(kernel_stack),%eax),%esp movl $ CPD_ACTIVE_THREAD,%ebx movl %gs:(%ebx),%ebx /* get active thread */ movl %ebx,%edx /* save for later */ FRAME_PCB_TO_STACK(%ebx) movl %ebx,%esp /* start running on new stack */ movl $0,CX(EXT(active_kloaded),%eax) /* set cached indicator */ jmp EXT(return_from_kernel) /* * Trap from kernel mode. No need to switch stacks or load segment registers. */ trap_from_kernel: #if MACH_KDB || MACH_KGDB mov $ CPU_DATA,%ax mov %ax,%gs movl %esp,%ebx /* save current stack */ cmpl EXT(int_stack_high),%esp /* on an interrupt stack? */ jb 6f /* OK if so */ #if MACH_KGDB cmpl $0,EXT(kgdb_active) /* Unexpected trap in kgdb */ je 0f /* no */ pushl %esp /* Already on kgdb stack */ cli call EXT(kgdb_trap) addl $4,%esp jmp EXT(return_from_kernel) 0: /* should kgdb handle this exception? */ cmpl $(T_NO_FPU),R_TRAPNO(%esp) /* FPU disabled? */ je 2f /* yes */ cmpl $(T_PAGE_FAULT),R_TRAPNO(%esp) /* page fault? */ je 2f /* yes */ 1: cli /* disable interrupts */ CPU_NUMBER(%edx) /* get CPU number */ movl CX(EXT(kgdb_stacks),%edx),%ebx xchgl %ebx,%esp /* switch to kgdb stack */ pushl %ebx /* pass old sp as an arg */ call EXT(kgdb_from_kernel) popl %esp /* switch back to kernel stack */ jmp EXT(return_from_kernel) 2: #endif /* MACH_KGDB */ #if MACH_KDB cmpl $0,EXT(db_active) /* could trap be from ddb? */ je 3f /* no */ #if NCPUS > 1 CPU_NUMBER(%edx) /* see if this CPU is in ddb */ cmpl $0,CX(EXT(kdb_active),%edx) je 3f /* no */ #endif /* NCPUS > 1 */ pushl %esp call EXT(db_trap_from_asm) addl $0x4,%esp jmp EXT(return_from_kernel) 3: /* * Dilemma: don't want to switch to kernel_stack if trap * "belongs" to ddb; don't want to switch to db_stack if * trap "belongs" to kernel. So have to duplicate here the * set of trap types that kernel_trap() handles. Note that * "unexpected" page faults will not be handled by kernel_trap(). * In this panic-worthy case, we fall into the debugger with * kernel_stack containing the call chain that led to the * bogus fault. */ movl R_TRAPNO(%esp),%edx cmpl $(T_PAGE_FAULT),%edx je 4f cmpl $(T_NO_FPU),%edx je 4f cmpl $(T_FPU_FAULT),%edx je 4f cmpl $(T_FLOATING_POINT_ERROR),%edx je 4f cmpl $(T_PREEMPT),%edx jne 7f 4: #endif /* MACH_KDB */ CPU_NUMBER(%edx) /* get CPU number */ cmpl CX(EXT(kernel_stack),%edx),%esp /* if not already on kernel stack, */ ja 5f /* check some more */ cmpl CX(EXT(active_stacks),%edx),%esp ja 6f /* on kernel stack: no switch */ 5: movl CX(EXT(kernel_stack),%edx),%esp 6: pushl %ebx /* save old stack */ pushl %ebx /* pass as parameter */ call EXT(kernel_trap) /* to kernel trap routine */ addl $4,%esp /* pop parameter */ testl %eax,%eax jne 8f /* * If kernel_trap returns false, trap wasn't handled. */ 7: #if MACH_KDB CPU_NUMBER(%edx) movl CX(EXT(db_stacks),%edx),%esp pushl %ebx /* pass old stack as parameter */ call EXT(db_trap_from_asm) #endif /* MACH_KDB */ #if MACH_KGDB cli /* disable interrupts */ CPU_NUMBER(%edx) /* get CPU number */ movl CX(EXT(kgdb_stacks),%edx),%esp pushl %ebx /* pass old stack as parameter */ call EXT(kgdb_from_kernel) #endif /* MACH_KGDB */ addl $4,%esp /* pop parameter */ testl %eax,%eax jne 8f /* * Likewise, if kdb_trap/kgdb_from_kernel returns false, trap * wasn't handled. */ pushl %ebx /* pass old stack as parameter */ call EXT(panic_trap) addl $4,%esp /* pop parameter */ 8: movl %ebx,%esp /* get old stack (from callee-saves reg) */ #else /* MACH_KDB || MACH_KGDB */ pushl %esp /* pass parameter */ call EXT(kernel_trap) /* to kernel trap routine */ addl $4,%esp /* pop parameter */ #endif /* MACH_KDB || MACH_KGDB */ #if MACH_RT CPU_NUMBER(%edx) movl CX(EXT(need_ast),%edx),%eax /* get pending asts */ testl $ AST_URGENT,%eax /* any urgent preemption? */ je EXT(return_from_kernel) /* no, nothing to do */ cmpl $0,EXT(preemptable) /* kernel-mode, preemption enabled? */ je EXT(return_from_kernel) /* no, skip it */ cmpl $ T_PREEMPT,48(%esp) /* preempt request? */ jne EXT(return_from_kernel) /* no, nothing to do */ movl CX(EXT(kernel_stack),%edx),%eax movl %esp,%ecx xorl %eax,%ecx andl $(-KERNEL_STACK_SIZE),%ecx testl %ecx,%ecx /* are we on the kernel stack? */ jne EXT(return_from_kernel) /* no, skip it */ #if PREEMPT_DEBUG_LOG pushl 28(%esp) /* stack pointer */ pushl 24+4(%esp) /* frame pointer */ pushl 56+8(%esp) /* stack pointer */ pushl $0f call EXT(log_thread_action) addl $16, %esp .data 0: String "trap preempt eip" .text #endif /* PREEMPT_DEBUG_LOG */ pushl $1 /* push preemption flag */ call EXT(i386_astintr) /* take the AST */ addl $4,%esp /* pop preemption flag */ #endif /* MACH_RT */ jmp EXT(return_from_kernel) /* * Called as a function, makes the current thread * return from the kernel as if from an exception. */ .globl EXT(thread_exception_return) .globl EXT(thread_bootstrap_return) LEXT(thread_exception_return) LEXT(thread_bootstrap_return) movl %esp,%ecx /* get kernel stack */ or $(KERNEL_STACK_SIZE-1),%ecx movl -3-IKS_SIZE(%ecx),%esp /* switch back to PCB stack */ jmp EXT(return_from_trap) Entry(call_continuation) movl S_ARG0,%eax /* get continuation */ movl %esp,%ecx /* get kernel stack */ or $(KERNEL_STACK_SIZE-1),%ecx addl $(-3-IKS_SIZE),%ecx movl %ecx,%esp /* pop the stack */ xorl %ebp,%ebp /* zero frame pointer */ jmp *%eax /* goto continuation */ #if 0 #define LOG_INTERRUPT(info,msg) \ pushal ; \ pushl msg ; \ pushl info ; \ call EXT(log_thread_action) ; \ add $8,%esp ; \ popal #define CHECK_INTERRUPT_TIME(n) \ pushal ; \ pushl $n ; \ call EXT(check_thread_time) ; \ add $4,%esp ; \ popal #else #define LOG_INTERRUPT(info,msg) #define CHECK_INTERRUPT_TIME(n) #endif .data imsg_start: String "interrupt start" imsg_end: String "interrupt end" .text /* * All interrupts enter here. * old %eax on stack; interrupt number in %eax. */ Entry(all_intrs) pushl %ecx /* save registers */ pushl %edx cld /* clear direction flag */ cmpl %ss:EXT(int_stack_high),%esp /* on an interrupt stack? */ jb int_from_intstack /* if not: */ pushl %ds /* save segment registers */ pushl %es pushl %fs pushl %gs mov %ss,%dx /* switch to kernel segments */ mov %dx,%ds mov %dx,%es mov $ CPU_DATA,%dx mov %dx,%gs CPU_NUMBER(%edx) movl CX(EXT(int_stack_top),%edx),%ecx movl %esp,%edx /* & i386_interrupt_state */ xchgl %ecx,%esp /* switch to interrupt stack */ #if STAT_TIME pushl %ecx /* save pointer to old stack */ #else pushl %ebx /* save %ebx - out of the way */ /* so stack looks the same */ pushl %ecx /* save pointer to old stack */ TIME_INT_ENTRY /* do timing */ #endif pushl %edx /* pass &i386_interrupt_state to pe_incoming_interrupt */ #if MACH_RT movl $ CPD_PREEMPTION_LEVEL,%edx incl %gs:(%edx) #endif /* MACH_RT */ movl $ CPD_INTERRUPT_LEVEL,%edx incl %gs:(%edx) pushl %eax /* Push trap number */ call EXT(PE_incoming_interrupt) /* call generic interrupt routine */ addl $8,%esp /* Pop trap number and eip */ .globl EXT(return_to_iret) LEXT(return_to_iret) /* (label for kdb_kintr and hardclock) */ movl $ CPD_INTERRUPT_LEVEL,%edx decl %gs:(%edx) #if MACH_RT movl $ CPD_PREEMPTION_LEVEL,%edx decl %gs:(%edx) #endif /* MACH_RT */ #if STAT_TIME #else TIME_INT_EXIT /* do timing */ movl 4(%esp),%ebx /* restore the extra reg we saved */ #endif popl %esp /* switch back to old stack */ CPU_NUMBER(%edx) movl CX(EXT(need_ast),%edx),%eax testl %eax,%eax /* any pending asts? */ je 1f /* no, nothing to do */ testl $(EFL_VM),I_EFL(%esp) /* if in V86 */ jnz ast_from_interrupt /* take it */ testb $3,I_CS(%esp) /* user mode, */ jnz ast_from_interrupt /* take it */ #ifdef FIXME cmpl ETEXT_ADDR,I_EIP(%esp) /* if within kernel-loaded task, */ jnb ast_from_interrupt /* take it */ #endif #if MACH_RT cmpl $0,EXT(preemptable) /* kernel-mode, preemption enabled? */ je 1f /* no, skip it */ movl $ CPD_PREEMPTION_LEVEL,%ecx cmpl $0,%gs:(%ecx) /* preemption masked? */ jne 1f /* yes, skip it */ testl $ AST_URGENT,%eax /* any urgent requests? */ je 1f /* no, skip it */ cmpl $ EXT(locore_end),I_EIP(%esp) /* are we in locore code? */ jb 1f /* yes, skip it */ movl CX(EXT(kernel_stack),%edx),%eax movl %esp,%ecx xorl %eax,%ecx andl $(-KERNEL_STACK_SIZE),%ecx testl %ecx,%ecx /* are we on the kernel stack? */ jne 1f /* no, skip it */ /* * Take an AST from kernel space. We don't need (and don't want) * to do as much as the case where the interrupt came from user * space. */ #if PREEMPT_DEBUG_LOG pushl $0 pushl $0 pushl I_EIP+8(%esp) pushl $0f call EXT(log_thread_action) addl $16, %esp .data 0: String "intr preempt eip" .text #endif /* PREEMPT_DEBUG_LOG */ sti pushl $1 /* push preemption flag */ call EXT(i386_astintr) /* take the AST */ addl $4,%esp /* pop preemption flag */ #endif /* MACH_RT */ 1: pop %gs pop %fs pop %es /* restore segment regs */ pop %ds pop %edx pop %ecx pop %eax iret /* return to caller */ int_from_intstack: #if MACH_RT movl $ CPD_PREEMPTION_LEVEL,%edx incl %gs:(%edx) #endif /* MACH_RT */ movl $ CPD_INTERRUPT_LEVEL,%edx incl %gs:(%edx) subl $16, %esp /* dummy ds, es, fs, gs */ movl %esp, %edx /* &i386_interrupt_state */ pushl %edx /* pass &i386_interrupt_state to PE_incoming_interrupt /* pushl %eax /* Push trap number */ call EXT(PE_incoming_interrupt) addl $20,%esp /* pop i386_interrupt_state, dummy gs,fs,es,ds */ LEXT(return_to_iret_i) /* ( label for kdb_kintr) */ addl $4,%esp /* pop trap number */ movl $ CPD_INTERRUPT_LEVEL,%edx decl %gs:(%edx) #if MACH_RT movl $ CPD_PREEMPTION_LEVEL,%edx decl %gs:(%edx) #endif /* MACH_RT */ pop %edx /* must have been on kernel segs */ pop %ecx pop %eax /* no ASTs */ iret /* * Take an AST from an interrupt. * On PCB stack. * sp-> es -> edx * ds -> ecx * edx -> eax * ecx -> trapno * eax -> code * eip * cs * efl * esp * ss */ ast_from_interrupt: pop %gs pop %fs pop %es /* restore all registers ... */ pop %ds popl %edx popl %ecx popl %eax sti /* Reenable interrupts */ pushl $0 /* zero code */ pushl $0 /* zero trap number */ pusha /* save general registers */ push %ds /* save segment registers */ push %es push %fs push %gs mov %ss,%dx /* switch to kernel segments */ mov %dx,%ds mov %dx,%es mov $ CPU_DATA,%dx mov %dx,%gs /* * See if we interrupted a kernel-loaded thread executing * in its own task. */ CPU_NUMBER(%edx) testl $(EFL_VM),R_EFLAGS(%esp) /* in V86 mode? */ jnz 0f /* user mode trap if so */ testb $3,R_CS(%esp) jnz 0f /* user mode, back to normal */ #ifdef FIXME cmpl ETEXT_ADDR,R_EIP(%esp) jb 0f /* not kernel-loaded, back to normal */ #endif /* * Transfer the current stack frame by hand into the PCB. */ CAH(afistart) movl CX(EXT(active_kloaded),%edx),%eax movl CX(EXT(kernel_stack),%edx),%ebx xchgl %ebx,%esp FRAME_STACK_TO_PCB(%eax,%ebx) CAH(afiend) TIME_TRAP_UENTRY jmp 3f 0: TIME_TRAP_UENTRY movl CX(EXT(kernel_stack),%edx),%eax /* switch to kernel stack */ xchgl %eax,%esp 3: pushl %eax pushl $0 /* push preemption flag */ call EXT(i386_astintr) /* take the AST */ addl $4,%esp /* pop preemption flag */ popl %esp /* back to PCB stack */ jmp EXT(return_from_trap) /* return */ #if MACH_KDB || MACH_KGDB /* * kdb_kintr: enter kdb from keyboard interrupt. * Chase down the stack frames until we find one whose return * address is the interrupt handler. At that point, we have: * * frame-> saved %ebp * return address in interrupt handler * ivect * saved SPL * return address == return_to_iret_i * saved %edx * saved %ecx * saved %eax * saved %eip * saved %cs * saved %efl * * OR: * frame-> saved %ebp * return address in interrupt handler * ivect * saved SPL * return address == return_to_iret * pointer to save area on old stack * [ saved %ebx, if accurate timing ] * * old stack: saved %es * saved %ds * saved %edx * saved %ecx * saved %eax * saved %eip * saved %cs * saved %efl * * Call kdb, passing it that register save area. */ #if MACH_KGDB Entry(kgdb_kintr) #endif /* MACH_KGDB */ #if MACH_KDB Entry(kdb_kintr) #endif /* MACH_KDB */ movl %ebp,%eax /* save caller`s frame pointer */ movl $ EXT(return_to_iret),%ecx /* interrupt return address 1 */ movl $ EXT(return_to_iret_i),%edx /* interrupt return address 2 */ 0: cmpl 16(%eax),%ecx /* does this frame return to */ /* interrupt handler (1)? */ je 1f cmpl $kdb_from_iret,16(%eax) je 1f cmpl 16(%eax),%edx /* interrupt handler (2)? */ je 2f /* if not: */ cmpl $kdb_from_iret_i,16(%eax) je 2f movl (%eax),%eax /* try next frame */ jmp 0b 1: movl $kdb_from_iret,16(%eax) /* returns to kernel/user stack */ ret 2: movl $kdb_from_iret_i,16(%eax) /* returns to interrupt stack */ ret /* * On return from keyboard interrupt, we will execute * kdb_from_iret_i * if returning to an interrupt on the interrupt stack * kdb_from_iret * if returning to an interrupt on the user or kernel stack */ kdb_from_iret: /* save regs in known locations */ #if STAT_TIME pushl %ebx /* caller`s %ebx is in reg */ #else movl 4(%esp),%eax /* get caller`s %ebx */ pushl %eax /* push on stack */ #endif pushl %ebp pushl %esi pushl %edi push %fs push %gs #if MACH_KGDB cli pushl %esp /* pass regs */ call EXT(kgdb_kentry) /* to kgdb */ addl $4,%esp /* pop parameters */ #endif /* MACH_KGDB */ #if MACH_KDB pushl %esp /* pass regs */ call EXT(kdb_kentry) /* to kdb */ addl $4,%esp /* pop parameters */ #endif /* MACH_KDB */ pop %gs /* restore registers */ pop %fs popl %edi popl %esi popl %ebp #if STAT_TIME popl %ebx #else popl %eax movl %eax,4(%esp) #endif jmp EXT(return_to_iret) /* normal interrupt return */ kdb_from_iret_i: /* on interrupt stack */ pop %edx /* restore saved registers */ pop %ecx pop %eax pushl $0 /* zero error code */ pushl $0 /* zero trap number */ pusha /* save general registers */ push %ds /* save segment registers */ push %es push %fs push %gs #if MACH_KGDB cli /* disable interrupts */ CPU_NUMBER(%edx) /* get CPU number */ movl CX(EXT(kgdb_stacks),%edx),%ebx xchgl %ebx,%esp /* switch to kgdb stack */ pushl %ebx /* pass old sp as an arg */ call EXT(kgdb_from_kernel) popl %esp /* switch back to interrupt stack */ #endif /* MACH_KGDB */ #if MACH_KDB pushl %esp /* pass regs, */ pushl $0 /* code, */ pushl $-1 /* type to kdb */ call EXT(kdb_trap) addl $12,%esp #endif /* MACH_KDB */ pop %gs /* restore segment registers */ pop %fs pop %es pop %ds popa /* restore general registers */ addl $8,%esp iret #endif /* MACH_KDB || MACH_KGDB */ /* * Mach RPC enters through a call gate, like a system call. */ Entry(mach_rpc) pushf /* save flags as soon as possible */ pushl %eax /* save system call number */ pushl $0 /* clear trap number slot */ pusha /* save the general registers */ pushl %ds /* and the segment registers */ pushl %es pushl %fs pushl %gs mov %ss,%dx /* switch to kernel data segment */ mov %dx,%ds mov %dx,%es mov $ CPU_DATA,%dx mov %dx,%gs /* * Shuffle eflags,eip,cs into proper places */ movl R_EIP(%esp),%ebx /* eflags are in EIP slot */ movl R_CS(%esp),%ecx /* eip is in CS slot */ movl R_EFLAGS(%esp),%edx /* cs is in EFLAGS slot */ movl %ecx,R_EIP(%esp) /* fix eip */ movl %edx,R_CS(%esp) /* fix cs */ movl %ebx,R_EFLAGS(%esp) /* fix eflags */ CPU_NUMBER(%edx) TIME_TRAP_UENTRY negl %eax /* get system call number */ shll $4,%eax /* manual indexing */ /* * Check here for mach_rpc from kernel-loaded task -- * - Note that kernel-loaded task returns via real return. * We didn't enter here "through" PCB (i.e., using ring 0 stack), * so transfer the stack frame into the PCB explicitly, then * start running on resulting "PCB stack". We have to set * up a simulated "uesp" manually, since there's none in the * frame. */ cmpl $0,CX(EXT(active_kloaded),%edx) jz 2f CAH(mrstart) movl CX(EXT(active_kloaded),%edx),%ebx movl CX(EXT(kernel_stack),%edx),%edx xchgl %edx,%esp FRAME_STACK_TO_PCB(%ebx,%edx) CAH(mrend) CPU_NUMBER(%edx) jmp 3f 2: CPU_NUMBER(%edx) movl CX(EXT(kernel_stack),%edx),%ebx /* get current kernel stack */ xchgl %ebx,%esp /* switch stacks - %ebx points to */ /* user registers. */ 3: /* * Register use on entry: * eax contains syscall number * ebx contains user regs pointer */ #undef RPC_TRAP_REGISTERS #ifdef RPC_TRAP_REGISTERS pushl R_ESI(%ebx) pushl R_EDI(%ebx) pushl R_ECX(%ebx) pushl R_EDX(%ebx) #else movl EXT(mach_trap_table)(%eax),%ecx /* get number of arguments */ jecxz 2f /* skip argument copy if none */ movl R_UESP(%ebx),%esi /* get user stack pointer */ lea 4(%esi,%ecx,4),%esi /* skip user return address, */ /* and point past last argument */ /* edx holds cpu number from above */ movl CX(EXT(active_kloaded),%edx),%edx /* point to current thread */ orl %edx,%edx /* if ! kernel-loaded, check addr */ jz 4f /* else */ mov %ds,%dx /* kernel data segment access */ jmp 5f 4: cmpl $(VM_MAX_ADDRESS),%esi /* in user space? */ ja mach_call_addr /* address error if not */ movl $ USER_DS,%edx /* user data segment access */ 5: mov %dx,%fs movl %esp,%edx /* save kernel ESP for error recovery */ 1: subl $4,%esi RECOVERY_SECTION RECOVER(mach_call_addr_push) pushl %fs:(%esi) /* push argument on stack */ loop 1b /* loop for all arguments */ #endif /* * Register use on entry: * eax contains syscall number * ebx contains user regs pointer */ 2: pushl %ebx /* arg ptr */ pushl %eax /* call # - preserved across */ call EXT(mach_call_start) addl $ 8, %esp movl %eax, %ebx /* need later */ CAH(call_call) call *EXT(mach_trap_table)+4(%eax) /* call procedure */ pushl %eax /* retval */ pushl %ebx /* call # */ call EXT(mach_call_end) addl $ 8, %esp movl %esp,%ecx /* get kernel stack */ or $(KERNEL_STACK_SIZE-1),%ecx movl -3-IKS_SIZE(%ecx),%esp /* switch back to PCB stack */ movl %eax,R_EAX(%esp) /* save return value */ jmp EXT(return_from_trap) /* return to user */ /* * Special system call entry for "int 0x80", which has the "eflags" * register saved at the right place already. * Fall back to the common syscall path after saving the registers. * * esp -> old eip * old cs * old eflags * old esp if trapped from user * old ss if trapped from user * * XXX: for the moment, we don't check for int 0x80 from kernel mode. */ Entry(syscall_int80) pushl %eax /* save system call number */ pushl $0 /* clear trap number slot */ pusha /* save the general registers */ pushl %ds /* and the segment registers */ pushl %es pushl %fs pushl %gs mov %ss,%dx /* switch to kernel data segment */ mov %dx,%ds mov %dx,%es mov $ CPU_DATA,%dx mov %dx,%gs jmp syscall_entry_3 /* * System call enters through a call gate. Flags are not saved - * we must shuffle stack to look like trap save area. * * esp-> old eip * old cs * old esp * old ss * * eax contains system call number. * * NB: below use of CPU_NUMBER assumes that macro will use correct * correct segment register for any kernel data accesses. */ Entry(syscall) syscall_entry: pushf /* save flags as soon as possible */ syscall_entry_2: pushl %eax /* save system call number */ pushl $0 /* clear trap number slot */ pusha /* save the general registers */ pushl %ds /* and the segment registers */ pushl %es pushl %fs pushl %gs mov %ss,%dx /* switch to kernel data segment */ mov %dx,%ds mov %dx,%es mov $ CPU_DATA,%dx mov %dx,%gs /* * Shuffle eflags,eip,cs into proper places */ movl R_EIP(%esp),%ebx /* eflags are in EIP slot */ movl R_CS(%esp),%ecx /* eip is in CS slot */ movl R_EFLAGS(%esp),%edx /* cs is in EFLAGS slot */ movl %ecx,R_EIP(%esp) /* fix eip */ movl %edx,R_CS(%esp) /* fix cs */ movl %ebx,R_EFLAGS(%esp) /* fix eflags */ syscall_entry_3: CPU_NUMBER(%edx) /* * Check here for syscall from kernel-loaded task -- * We didn't enter here "through" PCB (i.e., using ring 0 stack), * so transfer the stack frame into the PCB explicitly, then * start running on resulting "PCB stack". We have to set * up a simulated "uesp" manually, since there's none in the * frame. */ cmpl $0,CX(EXT(active_kloaded),%edx) jz 0f CAH(scstart) movl CX(EXT(active_kloaded),%edx),%ebx movl CX(EXT(kernel_stack),%edx),%edx xchgl %edx,%esp FRAME_STACK_TO_PCB(%ebx,%edx) CAH(scend) TIME_TRAP_UENTRY CPU_NUMBER(%edx) jmp 1f 0: TIME_TRAP_UENTRY CPU_NUMBER(%edx) movl CX(EXT(kernel_stack),%edx),%ebx /* get current kernel stack */ xchgl %ebx,%esp /* switch stacks - %ebx points to */ /* user registers. */ /* user regs pointer already set */ /* * Check for MACH or emulated system call * Register use (from here till we begin processing call): * eax contains system call number * ebx points to user regs */ 1: movl $ CPD_ACTIVE_THREAD,%edx movl %gs:(%edx),%edx /* get active thread */ movl ACT_TASK(%edx),%edx /* point to task */ movl TASK_EMUL(%edx),%edx /* get emulation vector */ orl %edx,%edx /* if none, */ je syscall_native /* do native system call */ movl %eax,%ecx /* copy system call number */ subl DISP_MIN(%edx),%ecx /* get displacement into syscall */ /* vector table */ jl syscall_native /* too low - native system call */ cmpl DISP_COUNT(%edx),%ecx /* check range */ jnl syscall_native /* too high - native system call */ movl DISP_VECTOR(%edx,%ecx,4),%edx /* get the emulation vector */ orl %edx,%edx /* emulated system call if not zero */ jnz syscall_emul /* * Native system call. * Register use on entry: * eax contains syscall number * ebx points to user regs */ syscall_native: negl %eax /* get system call number */ jl mach_call_range /* out of range if it was positive */ cmpl EXT(mach_trap_count),%eax /* check system call table bounds */ jg mach_call_range /* error if out of range */ shll $4,%eax /* manual indexing */ movl EXT(mach_trap_table)+4(%eax),%edx /* get procedure */ cmpl $ EXT(kern_invalid),%edx /* if not "kern_invalid" */ jne do_native_call /* go on with Mach syscall */ movl $ CPD_ACTIVE_THREAD,%edx movl %gs:(%edx),%edx /* get active thread */ movl ACT_TASK(%edx),%edx /* point to task */ movl TASK_EMUL(%edx),%edx /* get emulation vector */ orl %edx,%edx /* if it exists, */ jne do_native_call /* do native system call */ shrl $4,%eax /* restore syscall number */ jmp mach_call_range /* try it as a "server" syscall */ /* * Register use on entry: * eax contains syscall number * ebx contains user regs pointer */ do_native_call: movl EXT(mach_trap_table)(%eax),%ecx /* get number of arguments */ jecxz mach_call_call /* skip argument copy if none */ movl R_UESP(%ebx),%esi /* get user stack pointer */ lea 4(%esi,%ecx,4),%esi /* skip user return address, */ /* and point past last argument */ CPU_NUMBER(%edx) movl CX(EXT(active_kloaded),%edx),%edx /* point to current thread */ orl %edx,%edx /* if kernel-loaded, skip addr check */ jz 0f /* else */ mov %ds,%dx /* kernel data segment access */ jmp 1f 0: cmpl $(VM_MAX_ADDRESS),%esi /* in user space? */ ja mach_call_addr /* address error if not */ movl $ USER_DS,%edx /* user data segment access */ 1: mov %dx,%fs movl %esp,%edx /* save kernel ESP for error recovery */ 2: subl $4,%esi RECOVERY_SECTION RECOVER(mach_call_addr_push) pushl %fs:(%esi) /* push argument on stack */ loop 2b /* loop for all arguments */ /* * Register use on entry: * eax contains syscall number * ebx contains user regs pointer */ mach_call_call: CAH(call_call) #if ETAP_EVENT_MONITOR cmpl $0x200, %eax /* is this mach_msg? */ jz make_syscall /* if yes, don't record event */ pushal /* Otherwise: save registers */ pushl %eax /* push syscall number on stack*/ call EXT(etap_machcall_probe1) /* call event begin probe */ add $4,%esp /* restore stack */ popal /* restore registers */ call *EXT(mach_trap_table)+4(%eax) /* call procedure */ pushal call EXT(etap_machcall_probe2) /* call event end probe */ popal jmp skip_syscall /* syscall already made */ #endif /* ETAP_EVENT_MONITOR */ make_syscall: pushl %ebx /* arg ptr */ pushl %eax /* call # - preserved across */ call EXT(mach_call_start) addl $ 8, %esp movl %eax, %ebx /* need later */ call *EXT(mach_trap_table)+4(%eax) /* call procedure */ pushl %eax /* retval */ pushl %ebx /* call # */ call EXT(mach_call_end) addl $ 8, %esp skip_syscall: movl %esp,%ecx /* get kernel stack */ or $(KERNEL_STACK_SIZE-1),%ecx movl -3-IKS_SIZE(%ecx),%esp /* switch back to PCB stack */ movl %eax,R_EAX(%esp) /* save return value */ jmp EXT(return_from_trap) /* return to user */ /* * Address out of range. Change to page fault. * %esi holds failing address. * Register use on entry: * ebx contains user regs pointer */ mach_call_addr_push: movl %edx,%esp /* clean parameters from stack */ mach_call_addr: movl %esi,R_CR2(%ebx) /* set fault address */ movl $(T_PAGE_FAULT),R_TRAPNO(%ebx) /* set page-fault trap */ movl $(T_PF_USER),R_ERR(%ebx) /* set error code - read user space */ CAH(call_addr) jmp EXT(take_trap) /* treat as a trap */ /* * System call out of range. Treat as invalid-instruction trap. * (? general protection?) * Register use on entry: * eax contains syscall number */ mach_call_range: movl $ CPD_ACTIVE_THREAD,%edx movl %gs:(%edx),%edx /* get active thread */ movl ACT_TASK(%edx),%edx /* point to task */ movl TASK_EMUL(%edx),%edx /* get emulation vector */ orl %edx,%edx /* if emulator, */ jne EXT(syscall_failed) /* handle as illegal instruction */ /* else generate syscall exception: */ push %eax movl %esp,%edx push $1 /* code_cnt = 1 */ push %edx /* exception_type_t (see i/f docky) */ push $ EXC_SYSCALL CAH(call_range) call EXT(exception) /* no return */ .globl EXT(syscall_failed) LEXT(syscall_failed) movl %esp,%ecx /* get kernel stack */ or $(KERNEL_STACK_SIZE-1),%ecx movl -3-IKS_SIZE(%ecx),%esp /* switch back to PCB stack */ CPU_NUMBER(%edx) movl CX(EXT(kernel_stack),%edx),%ebx /* get current kernel stack */ xchgl %ebx,%esp /* switch stacks - %ebx points to */ /* user registers. */ /* user regs pointer already set */ movl $(T_INVALID_OPCODE),R_TRAPNO(%ebx) /* set invalid-operation trap */ movl $0,R_ERR(%ebx) /* clear error code */ CAH(failed) jmp EXT(take_trap) /* treat as a trap */ /* * User space emulation of system calls. * edx - user address to handle syscall * * User stack will become: * uesp-> eflags * eip * Register use on entry: * ebx contains user regs pointer * edx contains emulator vector address */ syscall_emul: movl R_UESP(%ebx),%edi /* get user stack pointer */ CPU_NUMBER(%eax) movl CX(EXT(active_kloaded),%eax),%eax orl %eax,%eax /* if thread not kernel-loaded, */ jz 0f /* do address checks */ subl $8,%edi mov %ds,%ax /* kernel data segment access */ jmp 1f /* otherwise, skip them */ 0: cmpl $(VM_MAX_ADDRESS),%edi /* in user space? */ ja syscall_addr /* address error if not */ subl $8,%edi /* push space for new arguments */ cmpl $(VM_MIN_ADDRESS),%edi /* still in user space? */ jb syscall_addr /* error if not */ movl $ USER_DS,%ax /* user data segment access */ 1: mov %ax,%fs movl R_EFLAGS(%ebx),%eax /* move flags */ RECOVERY_SECTION RECOVER(syscall_addr) movl %eax,%fs:0(%edi) /* to user stack */ movl R_EIP(%ebx),%eax /* move eip */ RECOVERY_SECTION RECOVER(syscall_addr) movl %eax,%fs:4(%edi) /* to user stack */ movl %edi,R_UESP(%ebx) /* set new user stack pointer */ movl %edx,R_EIP(%ebx) /* change return address to trap */ movl %ebx,%esp /* back to PCB stack */ CAH(emul) jmp EXT(return_from_trap) /* return to user */ /* * Address error - address is in %edi. * Register use on entry: * ebx contains user regs pointer */ syscall_addr: movl %edi,R_CR2(%ebx) /* set fault address */ movl $(T_PAGE_FAULT),R_TRAPNO(%ebx) /* set page-fault trap */ movl $(T_PF_USER),R_ERR(%ebx) /* set error code - read user space */ CAH(addr) jmp EXT(take_trap) /* treat as a trap */ /* */ /* * Utility routines. */ /* * Copy from user address space. * arg0: user address * arg1: kernel address * arg2: byte count */ Entry(copyinmsg) ENTRY(copyin) pushl %esi pushl %edi /* save registers */ movl 8+S_ARG0,%esi /* get user start address */ movl 8+S_ARG1,%edi /* get kernel destination address */ movl 8+S_ARG2,%edx /* get count */ lea 0(%esi,%edx),%eax /* get user end address + 1 */ movl $ CPD_ACTIVE_THREAD,%ecx movl %gs:(%ecx),%ecx /* get active thread */ movl ACT_MAP(%ecx),%ecx /* get act->map */ movl MAP_PMAP(%ecx),%ecx /* get map->pmap */ cmpl EXT(kernel_pmap), %ecx jz 1f movl $ USER_DS,%cx /* user data segment access */ mov %cx,%ds 1: cmpl %esi,%eax jb copyin_fail /* fail if wrap-around */ cld /* count up */ movl %edx,%ecx /* move by longwords first */ shrl $2,%ecx RECOVERY_SECTION RECOVER(copyin_fail) rep movsl /* move longwords */ movl %edx,%ecx /* now move remaining bytes */ andl $3,%ecx RECOVERY_SECTION RECOVER(copyin_fail) rep movsb xorl %eax,%eax /* return 0 for success */ copy_ret: mov %ss,%di /* restore kernel data segment */ mov %di,%ds popl %edi /* restore registers */ popl %esi ret /* and return */ copyin_fail: movl $ EFAULT,%eax /* return error for failure */ jmp copy_ret /* pop frame and return */ /* * Copy string from user address space. * arg0: user address * arg1: kernel address * arg2: max byte count * arg3: actual byte count (OUT) */ Entry(copyinstr) pushl %esi pushl %edi /* save registers */ movl 8+S_ARG0,%esi /* get user start address */ movl 8+S_ARG1,%edi /* get kernel destination address */ movl 8+S_ARG2,%edx /* get count */ lea 0(%esi,%edx),%eax /* get user end address + 1 */ movl $ CPD_ACTIVE_THREAD,%ecx movl %gs:(%ecx),%ecx /* get active thread */ movl ACT_MAP(%ecx),%ecx /* get act->map */ movl MAP_PMAP(%ecx),%ecx /* get map->pmap */ cmpl EXT(kernel_pmap), %ecx jne 0f mov %ds,%cx /* kernel data segment access */ jmp 1f 0: movl $ USER_DS,%cx /* user data segment access */ 1: mov %cx,%fs xorl %eax,%eax cmpl $0,%edx je 4f 2: RECOVERY_SECTION RECOVER(copystr_fail) /* copy bytes... */ movb %fs:(%esi),%eax incl %esi testl %edi,%edi /* if kernel address is ... */ jz 3f /* not NULL */ movb %eax,(%edi) /* copy the byte */ incl %edi 3: decl %edx je 5f /* Zero count.. error out */ cmpl $0,%eax jne 2b /* .. a NUL found? */ jmp 4f /* return zero (%eax) */ 5: movl $ ENAMETOOLONG,%eax /* String is too long.. */ 4: movl 8+S_ARG3,%edi /* get OUT len ptr */ cmpl $0,%edi jz copystr_ret /* if null, just return */ subl 8+S_ARG0,%esi movl %esi,(%edi) /* else set OUT arg to xfer len */ copystr_ret: popl %edi /* restore registers */ popl %esi ret /* and return */ copystr_fail: movl $ EFAULT,%eax /* return error for failure */ jmp copy_ret /* pop frame and return */ /* * Copy to user address space. * arg0: kernel address * arg1: user address * arg2: byte count */ Entry(copyoutmsg) ENTRY(copyout) pushl %esi pushl %edi /* save registers */ pushl %ebx movl 12+S_ARG0,%esi /* get kernel start address */ movl 12+S_ARG1,%edi /* get user start address */ movl 12+S_ARG2,%edx /* get count */ leal 0(%edi,%edx),%eax /* get user end address + 1 */ movl $ CPD_ACTIVE_THREAD,%ecx movl %gs:(%ecx),%ecx /* get active thread */ movl ACT_MAP(%ecx),%ecx /* get act->map */ movl MAP_PMAP(%ecx),%ecx /* get map->pmap */ cmpl EXT(kernel_pmap), %ecx jne 0f mov %ds,%cx /* else kernel data segment access */ jmp 1f 0: movl $ USER_DS,%cx 1: mov %cx,%es /* * Check whether user address space is writable * before writing to it - hardware is broken. * * Skip check if "user" address is really in * kernel space (i.e., if it's in a kernel-loaded * task). * * Register usage: * esi/edi source/dest pointers for rep/mov * ecx counter for rep/mov * edx counts down from 3rd arg * eax count of bytes for each (partial) page copy * ebx shadows edi, used to adjust edx */ movl %edi,%ebx /* copy edi for syncing up */ copyout_retry: /* if restarting after a partial copy, put edx back in sync, */ addl %ebx,%edx /* edx -= (edi - ebx); */ subl %edi,%edx / movl %edi,%ebx /* ebx = edi; */ /* * Copy only what fits on the current destination page. * Check for write-fault again on the next page. */ leal NBPG(%edi),%eax /* point to */ andl $(-NBPG),%eax /* start of next page */ subl %edi,%eax /* get number of bytes to that point */ cmpl %edx,%eax /* bigger than count? */ jle 1f /* if so, */ movl %edx,%eax /* use count */ 1: cld /* count up */ movl %eax,%ecx /* move by longwords first */ shrl $2,%ecx RECOVERY_SECTION RECOVER(copyout_fail) RETRY_SECTION RETRY(copyout_retry) rep movsl movl %eax,%ecx /* now move remaining bytes */ andl $3,%ecx RECOVERY_SECTION RECOVER(copyout_fail) RETRY_SECTION RETRY(copyout_retry) rep movsb /* move */ movl %edi,%ebx /* copy edi for syncing up */ subl %eax,%edx /* and decrement count */ jg copyout_retry /* restart on next page if not done */ xorl %eax,%eax /* return 0 for success */ copyout_ret: mov %ss,%di /* restore kernel segment */ mov %di,%es popl %ebx popl %edi /* restore registers */ popl %esi ret /* and return */ copyout_fail: movl $ EFAULT,%eax /* return error for failure */ jmp copyout_ret /* pop frame and return */ /* * FPU routines. */ /* * Initialize FPU. */ ENTRY(_fninit) fninit ret /* * Read control word */ ENTRY(_fstcw) pushl %eax /* get stack space */ fstcw (%esp) popl %eax ret /* * Set control word */ ENTRY(_fldcw) fldcw 4(%esp) ret /* * Read status word */ ENTRY(_fnstsw) xor %eax,%eax /* clear high 16 bits of eax */ fnstsw %ax /* read FP status */ ret /* * Clear FPU exceptions */ ENTRY(_fnclex) fnclex ret /* * Clear task-switched flag. */ ENTRY(_clts) clts ret /* * Save complete FPU state. Save error for later. */ ENTRY(_fpsave) movl 4(%esp),%eax /* get save area pointer */ fnsave (%eax) /* save complete state, including */ /* errors */ ret /* * Restore FPU state. */ ENTRY(_fprestore) movl 4(%esp),%eax /* get save area pointer */ frstor (%eax) /* restore complete state */ ret /* * Set cr3 */ ENTRY(set_cr3) #if NCPUS > 1 CPU_NUMBER(%eax) orl 4(%esp), %eax #else /* NCPUS > 1 && AT386 */ movl 4(%esp),%eax /* get new cr3 value */ #endif /* NCPUS > 1 && AT386 */ /* * Don't set PDBR to a new value (hence invalidating the * "paging cache") if the new value matches the current one. */ movl %cr3,%edx /* get current cr3 value */ cmpl %eax,%edx je 0f /* if two are equal, don't set */ movl %eax,%cr3 /* load it (and flush cache) */ 0: ret /* * Read cr3 */ ENTRY(get_cr3) movl %cr3,%eax #if NCPUS > 1 andl $(~0x7), %eax /* remove cpu number */ #endif /* NCPUS > 1 && AT386 */ ret /* * Flush TLB */ ENTRY(flush_tlb) movl %cr3,%eax /* flush tlb by reloading CR3 */ movl %eax,%cr3 /* with itself */ ret /* * Read cr2 */ ENTRY(get_cr2) movl %cr2,%eax ret /* * Read cr4 */ ENTRY(get_cr4) .byte 0x0f,0x20,0xe0 /* movl %cr4, %eax */ ret /* * Write cr4 */ ENTRY(set_cr4) movl 4(%esp), %eax .byte 0x0f,0x22,0xe0 /* movl %eax, %cr4 */ ret /* * Read ldtr */ Entry(get_ldt) xorl %eax,%eax sldt %ax ret /* * Set ldtr */ Entry(set_ldt) lldt 4(%esp) ret /* * Read task register. */ ENTRY(get_tr) xorl %eax,%eax str %ax ret /* * Set task register. Also clears busy bit of task descriptor. */ ENTRY(set_tr) movl S_ARG0,%eax /* get task segment number */ subl $8,%esp /* push space for SGDT */ sgdt 2(%esp) /* store GDT limit and base (linear) */ movl 4(%esp),%edx /* address GDT */ movb $(K_TSS),5(%edx,%eax) /* fix access byte in task descriptor */ ltr %ax /* load task register */ addl $8,%esp /* clear stack */ ret /* and return */ /* * Set task-switched flag. */ ENTRY(_setts) movl %cr0,%eax /* get cr0 */ orl $(CR0_TS),%eax /* or in TS bit */ movl %eax,%cr0 /* set cr0 */ ret /* * io register must not be used on slaves (no AT bus) */ #define ILL_ON_SLAVE #if MACH_ASSERT #define ARG0 B_ARG0 #define ARG1 B_ARG1 #define ARG2 B_ARG2 #define PUSH_FRAME FRAME #define POP_FRAME EMARF #else /* MACH_ASSERT */ #define ARG0 S_ARG0 #define ARG1 S_ARG1 #define ARG2 S_ARG2 #define PUSH_FRAME #define POP_FRAME #endif /* MACH_ASSERT */ #if MACH_KDB || MACH_ASSERT /* * Following routines are also defined as macros in i386/pio.h * Compile then when MACH_KDB is configured so that they * can be invoked from the debugger. */ /* * void outb(unsigned char *io_port, * unsigned char byte) * * Output a byte to an IO port. */ ENTRY(outb) PUSH_FRAME ILL_ON_SLAVE movl ARG0,%edx /* IO port address */ movl ARG1,%eax /* data to output */ outb %al,%dx /* send it out */ POP_FRAME ret /* * unsigned char inb(unsigned char *io_port) * * Input a byte from an IO port. */ ENTRY(inb) PUSH_FRAME ILL_ON_SLAVE movl ARG0,%edx /* IO port address */ xor %eax,%eax /* clear high bits of register */ inb %dx,%al /* get the byte */ POP_FRAME ret /* * void outw(unsigned short *io_port, * unsigned short word) * * Output a word to an IO port. */ ENTRY(outw) PUSH_FRAME ILL_ON_SLAVE movl ARG0,%edx /* IO port address */ movl ARG1,%eax /* data to output */ outw %ax,%dx /* send it out */ POP_FRAME ret /* * unsigned short inw(unsigned short *io_port) * * Input a word from an IO port. */ ENTRY(inw) PUSH_FRAME ILL_ON_SLAVE movl ARG0,%edx /* IO port address */ xor %eax,%eax /* clear high bits of register */ inw %dx,%ax /* get the word */ POP_FRAME ret /* * void outl(unsigned int *io_port, * unsigned int byte) * * Output an int to an IO port. */ ENTRY(outl) PUSH_FRAME ILL_ON_SLAVE movl ARG0,%edx /* IO port address*/ movl ARG1,%eax /* data to output */ outl %eax,%dx /* send it out */ POP_FRAME ret /* * unsigned int inl(unsigned int *io_port) * * Input an int from an IO port. */ ENTRY(inl) PUSH_FRAME ILL_ON_SLAVE movl ARG0,%edx /* IO port address */ inl %dx,%eax /* get the int */ POP_FRAME ret #endif /* MACH_KDB || MACH_ASSERT*/ /* * void loutb(unsigned byte *io_port, * unsigned byte *data, * unsigned int count) * * Output an array of bytes to an IO port. */ ENTRY(loutb) ENTRY(outsb) PUSH_FRAME ILL_ON_SLAVE movl %esi,%eax /* save register */ movl ARG0,%edx /* get io port number */ movl ARG1,%esi /* get data address */ movl ARG2,%ecx /* get count */ cld /* count up */ rep outsb /* output */ movl %eax,%esi /* restore register */ POP_FRAME ret /* * void loutw(unsigned short *io_port, * unsigned short *data, * unsigned int count) * * Output an array of shorts to an IO port. */ ENTRY(loutw) ENTRY(outsw) PUSH_FRAME ILL_ON_SLAVE movl %esi,%eax /* save register */ movl ARG0,%edx /* get io port number */ movl ARG1,%esi /* get data address */ movl ARG2,%ecx /* get count */ cld /* count up */ rep outsw /* output */ movl %eax,%esi /* restore register */ POP_FRAME ret /* * void loutw(unsigned short io_port, * unsigned int *data, * unsigned int count) * * Output an array of longs to an IO port. */ ENTRY(loutl) ENTRY(outsl) PUSH_FRAME ILL_ON_SLAVE movl %esi,%eax /* save register */ movl ARG0,%edx /* get io port number */ movl ARG1,%esi /* get data address */ movl ARG2,%ecx /* get count */ cld /* count up */ rep outsl /* output */ movl %eax,%esi /* restore register */ POP_FRAME ret /* * void linb(unsigned char *io_port, * unsigned char *data, * unsigned int count) * * Input an array of bytes from an IO port. */ ENTRY(linb) ENTRY(insb) PUSH_FRAME ILL_ON_SLAVE movl %edi,%eax /* save register */ movl ARG0,%edx /* get io port number */ movl ARG1,%edi /* get data address */ movl ARG2,%ecx /* get count */ cld /* count up */ rep insb /* input */ movl %eax,%edi /* restore register */ POP_FRAME ret /* * void linw(unsigned short *io_port, * unsigned short *data, * unsigned int count) * * Input an array of shorts from an IO port. */ ENTRY(linw) ENTRY(insw) PUSH_FRAME ILL_ON_SLAVE movl %edi,%eax /* save register */ movl ARG0,%edx /* get io port number */ movl ARG1,%edi /* get data address */ movl ARG2,%ecx /* get count */ cld /* count up */ rep insw /* input */ movl %eax,%edi /* restore register */ POP_FRAME ret /* * void linl(unsigned short io_port, * unsigned int *data, * unsigned int count) * * Input an array of longs from an IO port. */ ENTRY(linl) ENTRY(insl) PUSH_FRAME ILL_ON_SLAVE movl %edi,%eax /* save register */ movl ARG0,%edx /* get io port number */ movl ARG1,%edi /* get data address */ movl ARG2,%ecx /* get count */ cld /* count up */ rep insl /* input */ movl %eax,%edi /* restore register */ POP_FRAME ret /* * int inst_fetch(int eip, int cs); * * Fetch instruction byte. Return -1 if invalid address. */ .globl EXT(inst_fetch) LEXT(inst_fetch) movl S_ARG1, %eax /* get segment */ movw %ax,%fs /* into FS */ movl S_ARG0, %eax /* get offset */ RETRY_SECTION RETRY(EXT(inst_fetch)) /* re-load FS on retry */ RECOVERY_SECTION RECOVER(EXT(inst_fetch_fault)) movzbl %fs:(%eax),%eax /* load instruction byte */ ret LEXT(inst_fetch_fault) movl $-1,%eax /* return -1 if error */ ret #if MACH_KDP /* * kdp_copy_kmem(char *src, char *dst, int count) * * Similar to copyin except that both addresses are kernel addresses. */ ENTRY(kdp_copy_kmem) pushl %esi pushl %edi /* save registers */ movl 8+S_ARG0,%esi /* get kernel start address */ movl 8+S_ARG1,%edi /* get kernel destination address */ movl 8+S_ARG2,%edx /* get count */ lea 0(%esi,%edx),%eax /* get kernel end address + 1 */ cmpl %esi,%eax jb kdp_vm_read_fail /* fail if wrap-around */ cld /* count up */ movl %edx,%ecx /* move by longwords first */ shrl $2,%ecx RECOVERY_SECTION RECOVER(kdp_vm_read_fail) rep movsl /* move longwords */ movl %edx,%ecx /* now move remaining bytes */ andl $3,%ecx RECOVERY_SECTION RECOVER(kdp_vm_read_fail) rep movsb kdp_vm_read_done: movl 8+S_ARG2,%edx /* get count */ subl %ecx,%edx /* Return number of bytes transfered */ movl %edx,%eax popl %edi /* restore registers */ popl %esi ret /* and return */ kdp_vm_read_fail: xorl %eax,%eax /* didn't copy a thing. */ popl %edi popl %esi ret #endif /* * Done with recovery and retry tables. */ RECOVERY_SECTION RECOVER_TABLE_END RETRY_SECTION RETRY_TABLE_END ENTRY(dr6) movl %db6, %eax ret /* dr(address, type, len, persistence) */ ENTRY(dr0) movl S_ARG0, %eax movl %eax,EXT(dr_addr) movl %eax, %db0 movl $0, %ecx jmp 0f ENTRY(dr1) movl S_ARG0, %eax movl %eax,EXT(dr_addr)+1*4 movl %eax, %db1 movl $2, %ecx jmp 0f ENTRY(dr2) movl S_ARG0, %eax movl %eax,EXT(dr_addr)+2*4 movl %eax, %db2 movl $4, %ecx jmp 0f ENTRY(dr3) movl S_ARG0, %eax movl %eax,EXT(dr_addr)+3*4 movl %eax, %db3 movl $6, %ecx 0: pushl %ebp movl %esp, %ebp movl %db7, %edx movl %edx,EXT(dr_addr)+4*4 andl dr_msk(,%ecx,2),%edx /* clear out new entry */ movl %edx,EXT(dr_addr)+5*4 movzbl B_ARG3, %eax andb $3, %al shll %cl, %eax orl %eax, %edx movzbl B_ARG1, %eax andb $3, %al addb $0x10, %ecx shll %cl, %eax orl %eax, %edx movzbl B_ARG2, %eax andb $3, %al addb $0x2, %ecx shll %cl, %eax orl %eax, %edx movl %edx, %db7 movl %edx,EXT(dr_addr)+7*4 movl %edx, %eax leave ret .data DATA(preemptable) /* Not on an MP (makes cpu_number() usage unsafe) */ #if MACH_RT && (NCPUS == 1) .long 0 /* FIXME -- Currently disabled */ #else .long 0 /* FIX ME -- Currently disabled */ #endif /* MACH_RT && (NCPUS == 1) */ dr_msk: .long ~0x000f0003 .long ~0x00f0000c .long ~0x0f000030 .long ~0xf00000c0 ENTRY(dr_addr) .long 0,0,0,0 .long 0,0,0,0 .text ENTRY(get_cr0) movl %cr0, %eax ret ENTRY(set_cr0) movl 4(%esp), %eax movl %eax, %cr0 ret #ifndef SYMMETRY /* * ffs(mask) */ ENTRY(ffs) bsfl S_ARG0, %eax jz 0f incl %eax ret 0: xorl %eax, %eax ret /* * cpu_shutdown() * Force reboot */ null_idtr: .word 0 .long 0 Entry(cpu_shutdown) lidt null_idtr /* disable the interrupt handler */ xor %ecx,%ecx /* generate a divide by zero */ div %ecx,%eax /* reboot now */ ret /* this will "never" be executed */ #endif /* SYMMETRY */ /* * setbit(int bitno, int *s) - set bit in bit string */ ENTRY(setbit) movl S_ARG0, %ecx /* bit number */ movl S_ARG1, %eax /* address */ btsl %ecx, (%eax) /* set bit */ ret /* * clrbit(int bitno, int *s) - clear bit in bit string */ ENTRY(clrbit) movl S_ARG0, %ecx /* bit number */ movl S_ARG1, %eax /* address */ btrl %ecx, (%eax) /* clear bit */ ret /* * ffsbit(int *s) - find first set bit in bit string */ ENTRY(ffsbit) movl S_ARG0, %ecx /* address */ movl $0, %edx /* base offset */ 0: bsfl (%ecx), %eax /* check argument bits */ jnz 1f /* found bit, return */ addl $4, %ecx /* increment address */ addl $32, %edx /* increment offset */ jmp 0b /* try again */ 1: addl %edx, %eax /* return offset */ ret /* * testbit(int nr, volatile void *array) * * Test to see if the bit is set within the bit string */ ENTRY(testbit) movl S_ARG0,%eax /* Get the bit to test */ movl S_ARG1,%ecx /* get the array string */ btl %eax,(%ecx) sbbl %eax,%eax ret ENTRY(get_pc) movl 4(%ebp),%eax ret #if ETAP ENTRY(etap_get_pc) movl 4(%ebp), %eax /* fetch pc of caller */ ret ENTRY(tvals_to_etap) movl S_ARG0, %eax movl $1000000000, %ecx mull %ecx addl S_ARG1, %eax adc $0, %edx ret /* etap_time_t * etap_time_sub(etap_time_t stop, etap_time_t start) * * 64bit subtract, returns stop - start */ ENTRY(etap_time_sub) movl S_ARG0, %eax /* stop.low */ movl S_ARG1, %edx /* stop.hi */ subl S_ARG2, %eax /* stop.lo - start.lo */ sbbl S_ARG3, %edx /* stop.hi - start.hi */ ret #endif /* ETAP */ #if NCPUS > 1 ENTRY(minsecurity) pushl %ebp movl %esp,%ebp /* * jail: set the EIP to "jail" to block a kernel thread. * Useful to debug synchronization problems on MPs. */ ENTRY(jail) jmp EXT(jail) #endif /* NCPUS > 1 */ /* * unsigned int * div_scale(unsigned int dividend, * unsigned int divisor, * unsigned int *scale) * * This function returns (dividend << *scale) //divisor where *scale * is the largest possible value before overflow. This is used in * computation where precision must be achieved in order to avoid * floating point usage. * * Algorithm: * *scale = 0; * while (((dividend >> *scale) >= divisor)) * (*scale)++; * *scale = 32 - *scale; * return ((dividend << *scale) / divisor); */ ENTRY(div_scale) PUSH_FRAME xorl %ecx, %ecx /* *scale = 0 */ xorl %eax, %eax movl ARG0, %edx /* get dividend */ 0: cmpl ARG1, %edx /* if (divisor > dividend) */ jle 1f /* goto 1f */ addl $1, %ecx /* (*scale)++ */ shrdl $1, %edx, %eax /* dividend >> 1 */ shrl $1, %edx /* dividend >> 1 */ jmp 0b /* goto 0b */ 1: divl ARG1 /* (dividend << (32 - *scale)) / divisor */ movl ARG2, %edx /* get scale */ movl $32, (%edx) /* *scale = 32 */ subl %ecx, (%edx) /* *scale -= %ecx */ POP_FRAME ret /* * unsigned int * mul_scale(unsigned int multiplicand, * unsigned int multiplier, * unsigned int *scale) * * This function returns ((multiplicand * multiplier) >> *scale) where * scale is the largest possible value before overflow. This is used in * computation where precision must be achieved in order to avoid * floating point usage. * * Algorithm: * *scale = 0; * while (overflow((multiplicand * multiplier) >> *scale)) * (*scale)++; * return ((multiplicand * multiplier) >> *scale); */ ENTRY(mul_scale) PUSH_FRAME xorl %ecx, %ecx /* *scale = 0 */ movl ARG0, %eax /* get multiplicand */ mull ARG1 /* multiplicand * multiplier */ 0: cmpl $0, %edx /* if (!overflow()) */ je 1f /* goto 1 */ addl $1, %ecx /* (*scale)++ */ shrdl $1, %edx, %eax /* (multiplicand * multiplier) >> 1 */ shrl $1, %edx /* (multiplicand * multiplier) >> 1 */ jmp 0b 1: movl ARG2, %edx /* get scale */ movl %ecx, (%edx) /* set *scale */ POP_FRAME ret #ifdef MACH_BSD /* * BSD System call entry point.. */ Entry(trap_unix_syscall) trap_unix_addr: pushf /* save flags as soon as possible */ trap_unix_2: pushl %eax /* save system call number */ pushl $0 /* clear trap number slot */ pusha /* save the general registers */ pushl %ds /* and the segment registers */ pushl %es pushl %fs pushl %gs mov %ss,%dx /* switch to kernel data segment */ mov %dx,%ds mov %dx,%es mov $ CPU_DATA,%dx mov %dx,%gs /* * Shuffle eflags,eip,cs into proper places */ movl R_EIP(%esp),%ebx /* eflags are in EIP slot */ movl R_CS(%esp),%ecx /* eip is in CS slot */ movl R_EFLAGS(%esp),%edx /* cs is in EFLAGS slot */ movl %ecx,R_EIP(%esp) /* fix eip */ movl %edx,R_CS(%esp) /* fix cs */ movl %ebx,R_EFLAGS(%esp) /* fix eflags */ CPU_NUMBER(%edx) TIME_TRAP_UENTRY negl %eax /* get system call number */ shll $4,%eax /* manual indexing */ CPU_NUMBER(%edx) movl CX(EXT(kernel_stack),%edx),%ebx /* get current kernel stack */ xchgl %ebx,%esp /* switch stacks - %ebx points to */ /* user registers. */ /* * Register use on entry: * eax contains syscall number * ebx contains user regs pointer */ CAH(call_call) pushl %ebx /* Push the regs set onto stack */ call EXT(unix_syscall) popl %ebx movl %esp,%ecx /* get kernel stack */ or $(KERNEL_STACK_SIZE-1),%ecx movl -3-IKS_SIZE(%ecx),%esp /* switch back to PCB stack */ movl %eax,R_EAX(%esp) /* save return value */ jmp EXT(return_from_trap) /* return to user */ /* * Entry point for machdep system calls.. */ Entry(trap_machdep_syscall) pushf /* save flags as soon as possible */ pushl %eax /* save system call number */ pushl $0 /* clear trap number slot */ pusha /* save the general registers */ pushl %ds /* and the segment registers */ pushl %es pushl %fs pushl %gs mov %ss,%dx /* switch to kernel data segment */ mov %dx,%ds mov %dx,%es mov $ CPU_DATA,%dx mov %dx,%gs /* * Shuffle eflags,eip,cs into proper places */ movl R_EIP(%esp),%ebx /* eflags are in EIP slot */ movl R_CS(%esp),%ecx /* eip is in CS slot */ movl R_EFLAGS(%esp),%edx /* cs is in EFLAGS slot */ movl %ecx,R_EIP(%esp) /* fix eip */ movl %edx,R_CS(%esp) /* fix cs */ movl %ebx,R_EFLAGS(%esp) /* fix eflags */ CPU_NUMBER(%edx) TIME_TRAP_UENTRY negl %eax /* get system call number */ shll $4,%eax /* manual indexing */ CPU_NUMBER(%edx) movl CX(EXT(kernel_stack),%edx),%ebx /* get current kernel stack */ xchgl %ebx,%esp /* switch stacks - %ebx points to */ /* user registers. */ /* * Register use on entry: * eax contains syscall number * ebx contains user regs pointer */ CAH(call_call) pushl %ebx call EXT(machdep_syscall) popl %ebx movl %esp,%ecx /* get kernel stack */ or $(KERNEL_STACK_SIZE-1),%ecx movl -3-IKS_SIZE(%ecx),%esp /* switch back to PCB stack */ movl %eax,R_EAX(%esp) /* save return value */ jmp EXT(return_from_trap) /* return to user */ Entry(trap_mach25_syscall) pushf /* save flags as soon as possible */ pushl %eax /* save system call number */ pushl $0 /* clear trap number slot */ pusha /* save the general registers */ pushl %ds /* and the segment registers */ pushl %es pushl %fs pushl %gs mov %ss,%dx /* switch to kernel data segment */ mov %dx,%ds mov %dx,%es mov $ CPU_DATA,%dx mov %dx,%gs /* * Shuffle eflags,eip,cs into proper places */ movl R_EIP(%esp),%ebx /* eflags are in EIP slot */ movl R_CS(%esp),%ecx /* eip is in CS slot */ movl R_EFLAGS(%esp),%edx /* cs is in EFLAGS slot */ movl %ecx,R_EIP(%esp) /* fix eip */ movl %edx,R_CS(%esp) /* fix cs */ movl %ebx,R_EFLAGS(%esp) /* fix eflags */ CPU_NUMBER(%edx) TIME_TRAP_UENTRY negl %eax /* get system call number */ shll $4,%eax /* manual indexing */ CPU_NUMBER(%edx) movl CX(EXT(kernel_stack),%edx),%ebx /* get current kernel stack */ xchgl %ebx,%esp /* switch stacks - %ebx points to */ /* user registers. */ /* * Register use on entry: * eax contains syscall number * ebx contains user regs pointer */ CAH(call_call) pushl %ebx call EXT(mach25_syscall) popl %ebx movl %esp,%ecx /* get kernel stack */ or $(KERNEL_STACK_SIZE-1),%ecx movl -3-IKS_SIZE(%ecx),%esp /* switch back to PCB stack */ movl %eax,R_EAX(%esp) /* save return value */ jmp EXT(return_from_trap) /* return to user */ #endif