/*
- * Copyright (c) 2000-2005 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2000-2010 Apple Inc. All rights reserved.
*
- * @APPLE_LICENSE_HEADER_START@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
- * The contents of this file constitute Original Code as defined in and
- * are subject to the Apple Public Source License Version 1.1 (the
- * "License"). You may not use this file except in compliance with the
- * License. Please obtain a copy of the License at
- * http://www.apple.com/publicsource and read it before using this file.
+ * 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. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * unlawful or unlicensed copies of an Apple operating system, or to
+ * circumvent, violate, or enable the circumvention or violation of, any
+ * terms of an Apple operating system software license agreement.
*
- * This Original Code and all software distributed under the License are
- * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * 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 OR NON-INFRINGEMENT. Please see the
- * License for the specific language governing rights and limitations
- * under the License.
+ * 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@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
/*
* @OSF_COPYRIGHT@
*/
#include <i386/asm.h>
#include <assym.s>
-#include <mach_kdb.h>
#include <i386/eflags.h>
#include <i386/trap.h>
+#include <i386/rtclock_asm.h>
+#define _ARCH_I386_ASM_HELP_H_ /* Prevent inclusion of user header */
+#include <mach/i386/syscall_sw.h>
+#include <i386/postcode.h>
+#include <i386/proc_reg.h>
+#include <mach/exception_types.h>
+
+/*
+ * Low-memory handlers.
+ */
+#define LO_ALLINTRS EXT(lo_allintrs32)
+#define LO_ALLTRAPS EXT(lo_alltraps32)
+#define LO_SYSENTER EXT(lo_sysenter32)
+#define LO_UNIX_SCALL EXT(lo_unix_scall32)
+#define LO_MACH_SCALL EXT(lo_mach_scall32)
+#define LO_MDEP_SCALL EXT(lo_mdep_scall32)
#define HI_DATA(lo_addr) ( (EXT(lo_addr) - EXT(hi_remap_data)) + HIGH_IDT_BASE )
#define HI_TEXT(lo_text) ( (EXT(lo_text) - EXT(hi_remap_text)) + HIGH_MEM_BASE )
*/
#define IDT_BASE_ENTRY(vec,seg,type) \
.data ;\
- .long EXT(vec) - EXT(hi_remap_text) + HIGH_MEM_BASE ;\
+ .long EXT(vec) - EXT(hi_remap_text) + HIGH_MEM_BASE ; \
.word seg ;\
.byte 0 ;\
.byte type ;\
#define IDT_BASE_ENTRY_INT(vec,seg,type) \
.data ;\
- .long vec - EXT(hi_remap_text) + HIGH_MEM_BASE ;\
+ .long vec - EXT(hi_remap_text) + HIGH_MEM_BASE ; \
.word seg ;\
.byte 0 ;\
.byte type ;\
#define IDT_BASE_ENTRY_TG(vec,seg,type) \
.data ;\
- .long 0 ;\
+ .long 0 ; \
.word seg ;\
.byte 0 ;\
.byte type ;\
.text
-#define IDT_ENTRY(vec,type) IDT_BASE_ENTRY(vec,KERNEL_CS,type)
-#define IDT_ENTRY_INT(vec,type) IDT_BASE_ENTRY_INT(vec,KERNEL_CS,type)
+#define IDT_ENTRY(vec,type) IDT_BASE_ENTRY(vec,KERNEL32_CS,type)
+#define IDT_ENTRY_INT(vec,type) IDT_BASE_ENTRY_INT(vec,KERNEL32_CS,type)
/*
* No error code. Clear error code and push trap number.
pushl $0 ;\
pushl $(n) ;\
pusha ;\
- movl $ EXT(lo_alltraps),%ebx ;\
+ movl $(LO_ALLTRAPS),%ebx ;\
jmp enter_lohandler
pushl $0 ;\
pushl $(n) ;\
pusha ;\
- movl $ EXT(lo_alltraps),%ebx ;\
+ movl $(LO_ALLTRAPS),%ebx ;\
jmp enter_lohandler
* Extra-special interrupt code. Note that no offset may be
* specified in a task gate descriptor, so name is ignored.
*/
-#define EXCEP_TASK(n,name) \
- IDT_BASE_ENTRY_TG(0,DEBUG_TSS,K_TASK_GATE)
/* Double-fault fatal handler */
#define DF_FATAL_TASK(n,name) \
* Error code has been pushed. Push trap number.
*/
#define EXCEP_ERR(n,name) \
- IDT_ENTRY(name,K_INTR_GATE);\
-Entry(name) ;\
- pushl $(n) ;\
- pusha ;\
- movl $ EXT(lo_alltraps),%ebx ;\
+ IDT_ENTRY(name,K_INTR_GATE) ;\
+Entry(name) ;\
+ pushl $(n) ;\
+ pusha ;\
+ movl $(LO_ALLTRAPS),%ebx ;\
jmp enter_lohandler
pushl $0 ;\
pushl $(n) ;\
pusha ;\
- movl $ EXT(lo_allintrs),%ebx ;\
+ movl $(LO_ALLINTRS),%ebx ;\
jmp enter_lohandler
Entry(master_idt)
Entry(hi_remap_data)
.text
+ .align 12
Entry(hi_remap_text)
EXCEPTION(0x00,t_zero_div)
EXCEP_USR(0x05,t_bounds)
EXCEPTION(0x06,t_invop)
EXCEPTION(0x07,t_nofpu)
-#if MACH_KDB
-EXCEP_TASK(0x08,db_task_dbl_fault)
-#else
DF_FATAL_TASK(0x08,df_task_start)
-#endif
EXCEPTION(0x09,a_fpu_over)
EXCEPTION(0x0a,a_inv_tss)
EXCEP_SPC(0x0b,hi_segnp)
-#if MACH_KDB
-EXCEP_TASK(0x0c,db_task_stk_fault)
-#else
EXCEP_ERR(0x0c,t_stack_fault)
-#endif
EXCEP_SPC(0x0d,hi_gen_prot)
EXCEP_SPC(0x0e,hi_page_fault)
EXCEPTION(0x0f,t_trap_0f)
INTERRUPT(0x7c)
INTERRUPT(0x7d)
INTERRUPT(0x7e)
-INTERRUPT(0x7f)
+EXCEP_USR(0x7f, t_dtrace_ret)
EXCEP_SPC_USR(0x80,hi_unix_scall)
EXCEP_SPC_USR(0x81,hi_mach_scall)
EXCEP_SPC_USR(0x82,hi_mdep_scall)
-EXCEP_SPC_USR(0x83,hi_diag_scall)
-
+INTERRUPT(0x83)
INTERRUPT(0x84)
INTERRUPT(0x85)
INTERRUPT(0x86)
.text
-/*******************************************************************************************************
- *
+/*
* Trap/interrupt entry points.
*
* All traps must create the following save area on the PCB "stack":
* user ss - if from user
*/
-
+ret_to_kernel:
+ jmp *1f
+1: .long HI_TEXT(hi_ret_to_kernel)
+
+ret_to_user:
+ jmp *1f
+1: .long HI_TEXT(hi_ret_to_user)
+
Entry(hi_ret_to_user)
movl %esp,%ebx
movl %gs:CPU_ACTIVE_THREAD,%ecx
- subl ACT_PCB_ISS(%ecx),%ebx
- movl $(WINDOWS_CLEAN),ACT_COPYIO_STATE(%ecx)
+ subl TH_PCB_ISS(%ecx),%ebx
+ movl $(WINDOWS_CLEAN),TH_COPYIO_STATE(%ecx)
- movl ACT_PCB_IDS(%ecx),%eax /* get debug state struct */
+ movl TH_PCB_IDS(%ecx),%eax /* get debug state struct */
cmpl $0,%eax /* is there a debug state */
je 1f /* branch if not */
movl DS_DR0(%eax), %ecx /* Load the 32 bit debug registers */
EXT(ret_iret):
iret /* return from interrupt */
fast_exit:
- popl %edx /* user return eip */
- popl %ecx /* pop and toss cs */
+ popl %edx /* user return eip */
+ popl %ecx /* pop and toss cs */
andl $(~EFL_IF),(%esp) /* clear intrs enabled, see sti below */
- popf /* flags - carry denotes failure */
- popl %ecx /* user return esp */
+ popf /* flags - carry denotes failure */
+ popl %ecx /* user return esp */
sti /* interrupts enabled after sysexit */
- sysexit
-
-/*******************************************************************************************************/
+ sysexit
Entry(hi_unix_scall)
pushl %eax /* save system call number */
pushl $0 /* clear trap number slot */
pusha /* save the general registers */
- movl $ EXT(lo_unix_scall),%ebx
+ movl $(LO_UNIX_SCALL),%ebx
jmp enter_lohandler
pushl %eax /* save system call number */
pushl $0 /* clear trap number slot */
pusha /* save the general registers */
- movl $ EXT(lo_mach_scall),%ebx
+ movl $(LO_MACH_SCALL),%ebx
jmp enter_lohandler
pushl %eax /* save system call number */
pushl $0 /* clear trap number slot */
pusha /* save the general registers */
- movl $ EXT(lo_mdep_scall),%ebx
+ movl $(LO_MDEP_SCALL),%ebx
jmp enter_lohandler
-Entry(hi_diag_scall)
- pushl %eax // Save sselector
- pushl $0 // Clear trap number slot
- pusha // save the general registers
- movl $EXT(lo_diag_scall),%ebx // Get the function down low to transfer to
- jmp enter_lohandler // Leap to it...
-
-
/*
* sysenter entry point
* Requires user code to set up:
pushf /* flags */
/*
* Clear, among others, the Nested Task (NT) flags bit;
- * This is cleared by INT, but not by sysenter, which only
- * clears RF, VM and IF.
+ * This is cleared by INT, but not by SYSENTER.
*/
- pushl $0
+ pushl $0
popfl
pushl $(SYSENTER_CS) /* cs */
hi_sysenter_2:
pushl %eax /* err/eax - syscall code */
pushl $0 /* clear trap number slot */
pusha /* save the general registers */
- orl $(EFL_IF),R_EFLAGS-R_EDI(%esp) /* (edi was last reg pushed) */
- movl $ EXT(lo_sysenter),%ebx
+ orl $(EFL_IF),R32_EFLAGS-R32_EDI(%esp) /* (edi was last reg pushed) */
+ movl $(LO_SYSENTER),%ebx
enter_lohandler:
pushl %ds
pushl %es
pushl %fs
pushl %gs
-enter_lohandler1:
pushl $(SS_32) /* 32-bit state flavor */
+enter_lohandler1:
mov %ss,%eax
mov %eax,%ds
mov %eax,%fs
movl %ecx,%cr3
movl %ecx,%gs:CPU_ACTIVE_CR3
1:
- testb $3,R_CS(%esp)
+ testb $3,R32_CS(%esp)
jz 2f
movl %esp,%edx /* came from user mode */
+ xor %ebp, %ebp
subl %gs:CPU_HI_ISS,%edx
movl %gs:CPU_ACTIVE_THREAD,%ecx
- addl ACT_PCB_ISS(%ecx),%edx /* rebase the high stack to a low address */
+ addl TH_PCB_ISS(%ecx),%edx /* rebase the high stack to a low address */
movl %edx,%esp
- cmpl $0, ACT_PCB_IDS(%ecx) /* Is there a debug register state? */
+ cmpl $0, TH_PCB_IDS(%ecx) /* Is there a debug register state? */
je 2f
movl $0, %ecx /* If so, reset DR7 (the control) */
movl %ecx, %dr7
2:
- movl R_TRAPNO(%esp),%ecx // Get the interrupt vector
+ movl R32_TRAPNO(%esp),%ecx // Get the interrupt vector
addl $1,%gs:hwIntCnt(,%ecx,4) // Bump the count
- jmp *%ebx
+ jmp *%ebx
/*
pushl $(T_PAGE_FAULT) /* mark a page fault trap */
pusha /* save the general registers */
movl %cr2,%eax /* get the faulting address */
- movl %eax,R_CR2-R_EDI(%esp) /* save in esp save slot */
+ movl %eax,R32_CR2-R32_EDI(%esp)/* save in esp save slot */
- movl $ EXT(lo_alltraps),%ebx
+ movl $(LO_ALLTRAPS),%ebx
jmp enter_lohandler
pushl $0
pushl $(T_DEBUG) /* handle as user trap */
pusha /* save the general registers */
- movl $ EXT(lo_alltraps),%ebx
+ movl $(LO_ALLTRAPS),%ebx
jmp enter_lohandler
je fault_popl_gs
hi_take_trap:
pusha /* save the general registers */
- movl $ EXT(lo_alltraps),%ebx
+ movl $(LO_ALLTRAPS),%ebx
jmp enter_lohandler
popl %eax /* restore eax */
/* now treat as fault from user */
pusha /* save the general registers */
- movl $ EXT(lo_alltraps),%ebx
+ movl $(LO_ALLTRAPS),%ebx
jmp enter_lohandler
/*
push_gs:
pushl %gs /* restore gs. */
push_none:
- movl %eax,R_TRAPNO(%esp) /* set trap number */
- movl %edx,R_ERR(%esp) /* set error code */
+ pushl $(SS_32) /* 32-bit state flavor */
+ movl %eax,R32_TRAPNO(%esp) /* set trap number */
+ movl %edx,R32_ERR(%esp) /* set error code */
/* now treat as fault from user */
/* except that segment registers are */
/* already pushed */
- movl $ EXT(lo_alltraps),%ebx
+ movl $(LO_ALLTRAPS),%ebx
jmp enter_lohandler1
.text
-Entry(lo_ret_to_user)
- jmp *1f
-1: .long HI_TEXT(hi_ret_to_user)
+Entry(hi_remap_etext)
-Entry(lo_ret_to_kernel)
- jmp *1f
-1: .long HI_TEXT(hi_ret_to_kernel)
-Entry(hi_remap_etext)
+/*
+ * All 32 bit task 'exceptions' enter lo_alltraps:
+ * esp -> x86_saved_state_t
+ *
+ * The rest of the state is set up as:
+ * cr3 -> kernel directory
+ * esp -> low based stack
+ * gs -> CPU_DATA_GS
+ * cs -> KERNEL32_CS
+ * ss/ds/es -> KERNEL_DS
+ *
+ * interrupts disabled
+ * direction flag cleared
+ */
+Entry(lo_alltraps32)
+ movl R32_CS(%esp),%eax /* assume 32-bit state */
+ cmpl $(SS_64),SS_FLAVOR(%esp)/* 64-bit? */
+ jne 1f
+ movl R64_CS(%esp),%eax /* 64-bit user mode */
+1:
+ testb $3,%al
+ jz trap_from_kernel
+ /* user mode trap */
+ TIME_TRAP_UENTRY
+
+ movl %gs:CPU_ACTIVE_THREAD,%ecx
+ movl TH_TASK(%ecx),%ebx
+
+ /* Check for active vtimers in the current task */
+ TASK_VTIMER_CHECK(%ebx, %ecx)
+
+ movl %gs:CPU_KERNEL_STACK,%ebx
+ xchgl %ebx,%esp /* switch to kernel stack */
+
+ CCALL1(user_trap, %ebx) /* call user trap routine */
+ /* user_trap() unmasks interrupts */
+ cli /* hold off intrs - critical section */
+ xorl %ecx,%ecx /* don't check if we're in the PFZ */
+
+/*
+ * Return from trap or system call, checking for ASTs.
+ * On lowbase PCB stack with intrs disabled
+ */
+Entry(return_from_trap32)
+ movl %gs:CPU_ACTIVE_THREAD, %esp
+ movl TH_PCB_ISS(%esp), %esp /* switch back to PCB stack */
+ movl %gs:CPU_PENDING_AST, %eax
+ testl %eax, %eax
+ je EXT(return_to_user) /* branch if no AST */
+LEXT(return_from_trap_with_ast)
+ movl %gs:CPU_KERNEL_STACK, %ebx
+ xchgl %ebx, %esp /* switch to kernel stack */
+
+ testl %ecx, %ecx /* see if we need to check for an EIP in the PFZ */
+ je 2f /* no, go handle the AST */
+ cmpl $(SS_64), SS_FLAVOR(%ebx) /* are we a 64-bit task? */
+ je 1f
+ /* no... 32-bit user mode */
+ movl R32_EIP(%ebx), %eax
+ pushl %ebx /* save PCB stack */
+ xorl %ebp, %ebp /* clear frame pointer */
+ CCALL1(commpage_is_in_pfz32, %eax)
+ popl %ebx /* retrieve pointer to PCB stack */
+ testl %eax, %eax
+ je 2f /* not in the PFZ... go service AST */
+ movl %eax, R32_EBX(%ebx) /* let the PFZ know we've pended an AST */
+ xchgl %ebx, %esp /* switch back to PCB stack */
+ jmp EXT(return_to_user)
+1: /* 64-bit user mode */
+ movl R64_RIP(%ebx), %ecx
+ movl R64_RIP+4(%ebx), %eax
+ pushl %ebx /* save PCB stack */
+ xorl %ebp, %ebp /* clear frame pointer */
+ CCALL2(commpage_is_in_pfz64, %ecx, %eax)
+ popl %ebx /* retrieve pointer to PCB stack */
+ testl %eax, %eax
+ je 2f /* not in the PFZ... go service AST */
+ movl %eax, R64_RBX(%ebx) /* let the PFZ know we've pended an AST */
+ xchgl %ebx, %esp /* switch back to PCB stack */
+ jmp EXT(return_to_user)
+2:
+ sti /* interrupts always enabled on return to user mode */
+ xorl %ebp, %ebp /* Clear framepointer */
+ CCALL1(i386_astintr, $0) /* take the AST */
+ cli
+ xorl %ecx, %ecx /* don't check if we're in the PFZ */
+ jmp EXT(return_from_trap32) /* and check again (rare) */
+
+
+/*
+ * Trap from kernel mode. No need to switch stacks.
+ * Interrupts must be off here - we will set them to state at time of trap
+ * as soon as it's safe for us to do so and not recurse doing preemption
+ */
+trap_from_kernel:
+ movl %esp, %eax /* saved state addr */
+ pushl R32_EIP(%esp) /* Simulate a CALL from fault point */
+ pushl %ebp /* Extend framepointer chain */
+ movl %esp, %ebp
+ CCALL1WITHSP(kernel_trap, %eax) /* Call kernel trap handler */
+ popl %ebp
+ addl $4, %esp
+ cli
+
+ movl %gs:CPU_PENDING_AST,%eax /* get pending asts */
+ testl $ AST_URGENT,%eax /* any urgent preemption? */
+ je ret_to_kernel /* no, nothing to do */
+ cmpl $ T_PREEMPT,R32_TRAPNO(%esp)
+ je ret_to_kernel /* T_PREEMPT handled in kernel_trap() */
+ testl $ EFL_IF,R32_EFLAGS(%esp) /* interrupts disabled? */
+ je ret_to_kernel
+ cmpl $0,%gs:CPU_PREEMPTION_LEVEL /* preemption disabled? */
+ jne ret_to_kernel
+ movl %gs:CPU_KERNEL_STACK,%eax
+ movl %esp,%ecx
+ xorl %eax,%ecx
+ and EXT(kernel_stack_mask),%ecx
+ testl %ecx,%ecx /* are we on the kernel stack? */
+ jne ret_to_kernel /* no, skip it */
+
+ CCALL1(i386_astintr, $1) /* take the AST */
+
+ jmp ret_to_kernel
+
+
+/*
+ * All interrupts on all tasks enter here with:
+ * esp-> -> x86_saved_state_t
+ *
+ * cr3 -> kernel directory
+ * esp -> low based stack
+ * gs -> CPU_DATA_GS
+ * cs -> KERNEL32_CS
+ * ss/ds/es -> KERNEL_DS
+ *
+ * interrupts disabled
+ * direction flag cleared
+ */
+Entry(lo_allintrs32)
+ /*
+ * test whether already on interrupt stack
+ */
+ movl %gs:CPU_INT_STACK_TOP,%ecx
+ cmpl %esp,%ecx
+ jb 1f
+ leal -INTSTACK_SIZE(%ecx),%edx
+ cmpl %esp,%edx
+ jb int_from_intstack
+1:
+ xchgl %ecx,%esp /* switch to interrupt stack */
+
+ movl %cr0,%eax /* get cr0 */
+ orl $(CR0_TS),%eax /* or in TS bit */
+ movl %eax,%cr0 /* set cr0 */
+
+ subl $8, %esp /* for 16-byte stack alignment */
+ pushl %ecx /* save pointer to old stack */
+ movl %ecx,%gs:CPU_INT_STATE /* save intr state */
+
+ TIME_INT_ENTRY /* do timing */
+
+ movl %gs:CPU_ACTIVE_THREAD,%ecx
+ movl TH_TASK(%ecx),%ebx
+
+ /* Check for active vtimers in the current task */
+ TASK_VTIMER_CHECK(%ebx, %ecx)
+
+ incl %gs:CPU_PREEMPTION_LEVEL
+ incl %gs:CPU_INTERRUPT_LEVEL
+
+ movl %gs:CPU_INT_STATE, %eax
+ CCALL1(interrupt, %eax) /* call generic interrupt routine */
+
+ cli /* just in case we returned with intrs enabled */
+ xorl %eax,%eax
+ movl %eax,%gs:CPU_INT_STATE /* clear intr state pointer */
+
+ decl %gs:CPU_INTERRUPT_LEVEL
+ decl %gs:CPU_PREEMPTION_LEVEL
+
+ TIME_INT_EXIT /* do timing */
+
+ movl %gs:CPU_ACTIVE_THREAD,%eax
+ movl TH_PCB_FPS(%eax),%eax /* get pcb's ifps */
+ testl %eax, %eax /* Is there a context */
+ je 1f /* Branch if not */
+ cmpl $0, FP_VALID(%eax) /* Check fp_valid */
+ jne 1f /* Branch if valid */
+ clts /* Clear TS */
+ jmp 2f
+1:
+ movl %cr0,%eax /* get cr0 */
+ orl $(CR0_TS),%eax /* or in TS bit */
+ movl %eax,%cr0 /* set cr0 */
+2:
+ popl %esp /* switch back to old stack */
+
+ /* Load interrupted code segment into %eax */
+ movl R32_CS(%esp),%eax /* assume 32-bit state */
+ cmpl $(SS_64),SS_FLAVOR(%esp)/* 64-bit? */
+ jne 3f
+ movl R64_CS(%esp),%eax /* 64-bit user mode */
+3:
+ testb $3,%al /* user mode, */
+ jnz ast_from_interrupt_user /* go handle potential ASTs */
+ /*
+ * we only want to handle preemption requests if
+ * the interrupt fell in the kernel context
+ * and preemption isn't disabled
+ */
+ movl %gs:CPU_PENDING_AST,%eax
+ testl $ AST_URGENT,%eax /* any urgent requests? */
+ je ret_to_kernel /* no, nothing to do */
+
+ cmpl $0,%gs:CPU_PREEMPTION_LEVEL /* preemption disabled? */
+ jne ret_to_kernel /* yes, skip it */
+
+ movl %gs:CPU_KERNEL_STACK,%eax
+ movl %esp,%ecx
+ xorl %eax,%ecx
+ and EXT(kernel_stack_mask),%ecx
+ testl %ecx,%ecx /* are we on the kernel stack? */
+ jne ret_to_kernel /* 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.
+ */
+ CCALL1(i386_astintr, $1)
+
+ jmp ret_to_kernel
+
+
+/*
+ * nested int - simple path, can't preempt etc on way out
+ */
+int_from_intstack:
+ incl %gs:CPU_PREEMPTION_LEVEL
+ incl %gs:CPU_INTERRUPT_LEVEL
+
+ movl %esp, %edx /* x86_saved_state */
+ CCALL1(interrupt, %edx)
+
+ decl %gs:CPU_INTERRUPT_LEVEL
+ decl %gs:CPU_PREEMPTION_LEVEL
+
+ jmp ret_to_kernel
+
+/*
+ * Take an AST from an interrupted user
+ */
+ast_from_interrupt_user:
+ movl %gs:CPU_PENDING_AST,%eax
+ testl %eax,%eax /* pending ASTs? */
+ je ret_to_user /* no, nothing to do */
+
+ TIME_TRAP_UENTRY
+
+ movl $1, %ecx /* check if we're in the PFZ */
+ jmp EXT(return_from_trap_with_ast) /* return */
+
+
+/*
+ * 32bit Tasks
+ * System call entries via INTR_GATE or sysenter:
+ *
+ * esp -> x86_saved_state32_t
+ * cr3 -> kernel directory
+ * esp -> low based stack
+ * gs -> CPU_DATA_GS
+ * cs -> KERNEL32_CS
+ * ss/ds/es -> KERNEL_DS
+ *
+ * interrupts disabled
+ * direction flag cleared
+ */
+
+Entry(lo_sysenter32)
+ /*
+ * We can be here either for a mach syscall or a unix syscall,
+ * as indicated by the sign of the code:
+ */
+ movl R32_EAX(%esp),%eax
+ testl %eax,%eax
+ js EXT(lo_mach_scall32) /* < 0 => mach */
+ /* > 0 => unix */
+
+Entry(lo_unix_scall32)
+ TIME_TRAP_UENTRY
+
+ movl %gs:CPU_KERNEL_STACK,%edi
+ xchgl %edi,%esp /* switch to kernel stack */
+ movl %gs:CPU_ACTIVE_THREAD,%ecx /* get current thread */
+ movl TH_TASK(%ecx),%ebx /* point to current task */
+ incl TH_SYSCALLS_UNIX(%ecx) /* increment call count */
+
+ /* Check for active vtimers in the current task */
+ TASK_VTIMER_CHECK(%ebx, %ecx)
+
+ sti
+
+ CCALL1(unix_syscall, %edi)
+ /*
+ * always returns through thread_exception_return
+ */
+
+
+Entry(lo_mach_scall32)
+ TIME_TRAP_UENTRY
+
+ movl %gs:CPU_KERNEL_STACK,%edi
+ xchgl %edi,%esp /* switch to kernel stack */
+ movl %gs:CPU_ACTIVE_THREAD,%ecx /* get current thread */
+ movl TH_TASK(%ecx),%ebx /* point to current task */
+ incl TH_SYSCALLS_MACH(%ecx) /* increment call count */
+
+ /* Check for active vtimers in the current task */
+ TASK_VTIMER_CHECK(%ebx, %ecx)
+
+ sti
+
+ CCALL1(mach_call_munger, %edi)
+ /*
+ * always returns through thread_exception_return
+ */
+
+
+Entry(lo_mdep_scall32)
+ TIME_TRAP_UENTRY
+
+ movl %gs:CPU_KERNEL_STACK,%edi
+ xchgl %edi,%esp /* switch to kernel stack */
+ movl %gs:CPU_ACTIVE_THREAD,%ecx /* get current thread */
+ movl TH_TASK(%ecx),%ebx /* point to current task */
+
+ /* Check for active vtimers in the current task */
+ TASK_VTIMER_CHECK(%ebx, %ecx)
+
+ sti
+
+ CCALL1(machdep_syscall, %edi)
+ /*
+ * always returns through thread_exception_return
+ */
+
+
+LEXT(return_to_user)
+ TIME_TRAP_UEXIT
+ jmp ret_to_user
+
+
+/*
+ * Double-fault exception handler task. The last gasp...
+ */
+Entry(df_task_start)
+ CCALL1(panic_double_fault32, $(T_DOUBLE_FAULT))
+ hlt
+
+
+/*
+ * machine-check handler task. The last gasp...
+ */
+Entry(mc_task_start)
+ CCALL1(panic_machine_check32, $(T_MACHINE_CHECK))
+ hlt