/* * Copyright (c) 2000-2005 Apple Computer, Inc. All rights reserved. * * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ * * 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. * * 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_OSREFERENCE_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 #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 ) /* * Interrupt descriptor table and code vectors for it. */ #define IDT_BASE_ENTRY(vec,seg,type) \ .data ;\ .long EXT(vec) - EXT(hi_remap_text) + HIGH_MEM_BASE ;\ .word seg ;\ .byte 0 ;\ .byte type ;\ .text #define IDT_BASE_ENTRY_INT(vec,seg,type) \ .data ;\ .long vec - EXT(hi_remap_text) + HIGH_MEM_BASE ;\ .word seg ;\ .byte 0 ;\ .byte type ;\ .text #define IDT_BASE_ENTRY_TG(vec,seg,type) \ .data ;\ .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) /* * No error code. Clear error code and push trap number. */ #define EXCEPTION(n,name) \ IDT_ENTRY(name,K_INTR_GATE);\ Entry(name) ;\ pushl $0 ;\ pushl $(n) ;\ pusha ;\ movl $ EXT(lo_alltraps),%ebx ;\ jmp enter_lohandler /* * Interrupt from user. Clear error code and push trap number. */ #define EXCEP_USR(n,name) \ IDT_ENTRY(name,U_INTR_GATE);\ Entry(name) ;\ pushl $0 ;\ pushl $(n) ;\ pusha ;\ movl $ EXT(lo_alltraps),%ebx ;\ jmp enter_lohandler /* * Special interrupt code. */ #define EXCEP_SPC(n,name) \ IDT_ENTRY(name,K_INTR_GATE) /* * Special interrupt code from user. */ #define EXCEP_SPC_USR(n,name) \ IDT_ENTRY(name,U_INTR_GATE) /* * 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) \ IDT_BASE_ENTRY_TG(0,DF_TSS,K_TASK_GATE) /* machine-check handler */ #define MC_FATAL_TASK(n,name) \ IDT_BASE_ENTRY_TG(0,MC_TSS,K_TASK_GATE) /* * 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 ;\ jmp enter_lohandler /* * Interrupt. */ #define INTERRUPT(n) \ IDT_ENTRY_INT(L_ ## n,K_INTR_GATE) ;\ .align FALIGN ;\ L_ ## n: ;\ pushl $0 ;\ pushl $(n) ;\ pusha ;\ movl $ EXT(lo_allintrs),%ebx ;\ jmp enter_lohandler .data .align 12 Entry(master_idt) Entry(hi_remap_data) .text Entry(hi_remap_text) EXCEPTION(0x00,t_zero_div) EXCEP_SPC(0x01,hi_debug) INTERRUPT(0x02) /* NMI */ EXCEP_USR(0x03,t_int3) EXCEP_USR(0x04,t_into) 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) EXCEPTION(0x10,t_fpu_err) EXCEPTION(0x11,t_trap_11) MC_FATAL_TASK(0x12,mc_task_start) EXCEPTION(0x13,t_sse_err) EXCEPTION(0x14,t_trap_14) EXCEPTION(0x15,t_trap_15) EXCEPTION(0x16,t_trap_16) EXCEPTION(0x17,t_trap_17) EXCEPTION(0x18,t_trap_18) EXCEPTION(0x19,t_trap_19) EXCEPTION(0x1a,t_trap_1a) EXCEPTION(0x1b,t_trap_1b) EXCEPTION(0x1c,t_trap_1c) EXCEPTION(0x1d,t_trap_1d) EXCEPTION(0x1e,t_trap_1e) EXCEPTION(0x1f,t_trap_1f) INTERRUPT(0x20) INTERRUPT(0x21) INTERRUPT(0x22) INTERRUPT(0x23) INTERRUPT(0x24) INTERRUPT(0x25) INTERRUPT(0x26) INTERRUPT(0x27) INTERRUPT(0x28) INTERRUPT(0x29) INTERRUPT(0x2a) INTERRUPT(0x2b) INTERRUPT(0x2c) INTERRUPT(0x2d) INTERRUPT(0x2e) INTERRUPT(0x2f) INTERRUPT(0x30) INTERRUPT(0x31) INTERRUPT(0x32) INTERRUPT(0x33) INTERRUPT(0x34) INTERRUPT(0x35) INTERRUPT(0x36) INTERRUPT(0x37) INTERRUPT(0x38) INTERRUPT(0x39) INTERRUPT(0x3a) INTERRUPT(0x3b) INTERRUPT(0x3c) INTERRUPT(0x3d) INTERRUPT(0x3e) INTERRUPT(0x3f) INTERRUPT(0x40) INTERRUPT(0x41) INTERRUPT(0x42) INTERRUPT(0x43) INTERRUPT(0x44) INTERRUPT(0x45) INTERRUPT(0x46) INTERRUPT(0x47) INTERRUPT(0x48) INTERRUPT(0x49) INTERRUPT(0x4a) INTERRUPT(0x4b) INTERRUPT(0x4c) INTERRUPT(0x4d) INTERRUPT(0x4e) INTERRUPT(0x4f) INTERRUPT(0x50) INTERRUPT(0x51) INTERRUPT(0x52) INTERRUPT(0x53) INTERRUPT(0x54) INTERRUPT(0x55) INTERRUPT(0x56) INTERRUPT(0x57) INTERRUPT(0x58) INTERRUPT(0x59) INTERRUPT(0x5a) INTERRUPT(0x5b) INTERRUPT(0x5c) INTERRUPT(0x5d) INTERRUPT(0x5e) INTERRUPT(0x5f) INTERRUPT(0x60) INTERRUPT(0x61) INTERRUPT(0x62) INTERRUPT(0x63) INTERRUPT(0x64) INTERRUPT(0x65) INTERRUPT(0x66) INTERRUPT(0x67) INTERRUPT(0x68) INTERRUPT(0x69) INTERRUPT(0x6a) INTERRUPT(0x6b) INTERRUPT(0x6c) INTERRUPT(0x6d) INTERRUPT(0x6e) INTERRUPT(0x6f) INTERRUPT(0x70) INTERRUPT(0x71) INTERRUPT(0x72) INTERRUPT(0x73) INTERRUPT(0x74) INTERRUPT(0x75) INTERRUPT(0x76) INTERRUPT(0x77) INTERRUPT(0x78) INTERRUPT(0x79) INTERRUPT(0x7a) INTERRUPT(0x7b) INTERRUPT(0x7c) INTERRUPT(0x7d) INTERRUPT(0x7e) INTERRUPT(0x7f) 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(0x84) INTERRUPT(0x85) INTERRUPT(0x86) INTERRUPT(0x87) INTERRUPT(0x88) INTERRUPT(0x89) INTERRUPT(0x8a) INTERRUPT(0x8b) INTERRUPT(0x8c) INTERRUPT(0x8d) INTERRUPT(0x8e) INTERRUPT(0x8f) INTERRUPT(0x90) INTERRUPT(0x91) INTERRUPT(0x92) INTERRUPT(0x93) INTERRUPT(0x94) INTERRUPT(0x95) INTERRUPT(0x96) INTERRUPT(0x97) INTERRUPT(0x98) INTERRUPT(0x99) INTERRUPT(0x9a) INTERRUPT(0x9b) INTERRUPT(0x9c) INTERRUPT(0x9d) INTERRUPT(0x9e) INTERRUPT(0x9f) INTERRUPT(0xa0) INTERRUPT(0xa1) INTERRUPT(0xa2) INTERRUPT(0xa3) INTERRUPT(0xa4) INTERRUPT(0xa5) INTERRUPT(0xa6) INTERRUPT(0xa7) INTERRUPT(0xa8) INTERRUPT(0xa9) INTERRUPT(0xaa) INTERRUPT(0xab) INTERRUPT(0xac) INTERRUPT(0xad) INTERRUPT(0xae) INTERRUPT(0xaf) INTERRUPT(0xb0) INTERRUPT(0xb1) INTERRUPT(0xb2) INTERRUPT(0xb3) INTERRUPT(0xb4) INTERRUPT(0xb5) INTERRUPT(0xb6) INTERRUPT(0xb7) INTERRUPT(0xb8) INTERRUPT(0xb9) INTERRUPT(0xba) INTERRUPT(0xbb) INTERRUPT(0xbc) INTERRUPT(0xbd) INTERRUPT(0xbe) INTERRUPT(0xbf) INTERRUPT(0xc0) INTERRUPT(0xc1) INTERRUPT(0xc2) INTERRUPT(0xc3) INTERRUPT(0xc4) INTERRUPT(0xc5) INTERRUPT(0xc6) INTERRUPT(0xc7) INTERRUPT(0xc8) INTERRUPT(0xc9) INTERRUPT(0xca) INTERRUPT(0xcb) INTERRUPT(0xcc) INTERRUPT(0xcd) INTERRUPT(0xce) INTERRUPT(0xcf) INTERRUPT(0xd0) INTERRUPT(0xd1) INTERRUPT(0xd2) INTERRUPT(0xd3) INTERRUPT(0xd4) INTERRUPT(0xd5) INTERRUPT(0xd6) INTERRUPT(0xd7) INTERRUPT(0xd8) INTERRUPT(0xd9) INTERRUPT(0xda) INTERRUPT(0xdb) INTERRUPT(0xdc) INTERRUPT(0xdd) INTERRUPT(0xde) INTERRUPT(0xdf) INTERRUPT(0xe0) INTERRUPT(0xe1) INTERRUPT(0xe2) INTERRUPT(0xe3) INTERRUPT(0xe4) INTERRUPT(0xe5) INTERRUPT(0xe6) INTERRUPT(0xe7) INTERRUPT(0xe8) INTERRUPT(0xe9) INTERRUPT(0xea) INTERRUPT(0xeb) INTERRUPT(0xec) INTERRUPT(0xed) INTERRUPT(0xee) INTERRUPT(0xef) INTERRUPT(0xf0) INTERRUPT(0xf1) INTERRUPT(0xf2) INTERRUPT(0xf3) INTERRUPT(0xf4) INTERRUPT(0xf5) INTERRUPT(0xf6) INTERRUPT(0xf7) INTERRUPT(0xf8) INTERRUPT(0xf9) INTERRUPT(0xfa) INTERRUPT(0xfb) INTERRUPT(0xfc) INTERRUPT(0xfd) INTERRUPT(0xfe) EXCEPTION(0xff,t_preempt) .data Entry(lo_kernel_cr3) .long 0 .long 0 .text /******************************************************************************************************* * * 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 */ 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) movl ACT_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 */ movl %ecx, %db0 movl DS_DR1(%eax), %ecx movl %ecx, %db1 movl DS_DR2(%eax), %ecx movl %ecx, %db2 movl DS_DR3(%eax), %ecx movl %ecx, %db3 movl DS_DR7(%eax), %eax 1: addl %gs:CPU_HI_ISS,%ebx /* rebase PCB save area to high addr */ movl %gs:CPU_TASK_CR3,%ecx movl %ecx,%gs:CPU_ACTIVE_CR3 movl %ebx,%esp /* switch to hi based PCB stack */ movl %ecx,%cr3 /* switch to user's address space */ cmpl $0,%eax /* is dr7 set to something? */ je 2f /* branch if not */ movl %eax,%db7 /* Set dr7 */ 2: Entry(hi_ret_to_kernel) popl %eax /* ignore flavor of saved state */ EXT(ret_popl_gs): popl %gs /* restore segment registers */ EXT(ret_popl_fs): popl %fs EXT(ret_popl_es): popl %es EXT(ret_popl_ds): popl %ds popa /* restore general registers */ addl $8,%esp /* discard trap number and error code */ cmpl $(SYSENTER_CS),4(%esp) /* test for fast entry/exit */ je fast_exit EXT(ret_iret): iret /* return from interrupt */ fast_exit: 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 */ sti /* interrupts enabled after 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 jmp enter_lohandler Entry(hi_mach_scall) pushl %eax /* save system call number */ pushl $0 /* clear trap number slot */ pusha /* save the general registers */ movl $ EXT(lo_mach_scall),%ebx jmp enter_lohandler Entry(hi_mdep_scall) pushl %eax /* save system call number */ pushl $0 /* clear trap number slot */ pusha /* save the general registers */ movl $ EXT(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: * edx: user instruction pointer (return address) * ecx: user stack pointer * on which is pushed stub ret addr and saved ebx * Return to user-space is made using sysexit. * Note: sysenter/sysexit cannot be used for calls returning a value in edx, * or requiring ecx to be preserved. */ Entry(hi_sysenter) movl (%esp), %esp /* switch from intr stack to pcb */ /* * Push values on to the PCB stack * to cons up the saved state. */ pushl $(USER_DS) /* ss */ pushl %ecx /* uesp */ 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. */ pushl $0 popfl pushl $(SYSENTER_CS) /* cs */ hi_sysenter_2: pushl %edx /* eip */ 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 enter_lohandler: pushl %ds pushl %es pushl %fs pushl %gs enter_lohandler1: pushl $(SS_32) /* 32-bit state flavor */ mov %ss,%eax mov %eax,%ds mov %eax,%fs mov %eax,%es /* switch to kernel data seg */ mov $(CPU_DATA_GS),%eax mov %eax,%gs cld /* clear direction flag */ /* * Switch to kernel's address space if necessary */ movl HI_DATA(lo_kernel_cr3),%ecx movl %cr3,%eax cmpl %eax,%ecx je 1f movl %ecx,%cr3 movl %ecx,%gs:CPU_ACTIVE_CR3 1: testb $3,R_CS(%esp) jz 2f movl %esp,%edx /* came from user mode */ 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 */ movl %edx,%esp cmpl $0, ACT_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 addl $1,%gs:hwIntCnt(,%ecx,4) // Bump the count jmp *%ebx /* * Page fault traps save cr2. */ Entry(hi_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,R_CR2-R_EDI(%esp) /* save in esp save slot */ movl $ EXT(lo_alltraps),%ebx jmp enter_lohandler /* * 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(hi_debug) testb $3,4(%esp) jnz hi_debug_trap /* trap came from kernel mode */ cmpl $(HI_TEXT(hi_mach_scall)),(%esp) jne 6f addl $12,%esp /* remove eip/cs/eflags from debug_trap */ jmp EXT(hi_mach_scall) /* continue system call entry */ 6: cmpl $(HI_TEXT(hi_mdep_scall)),(%esp) jne 5f addl $12,%esp /* remove eip/cs/eflags from debug_trap */ jmp EXT(hi_mdep_scall) /* continue system call entry */ 5: cmpl $(HI_TEXT(hi_unix_scall)),(%esp) jne 4f addl $12,%esp /* remove eip/cs/eflags from debug_trap */ jmp EXT(hi_unix_scall) /* continue system call entry */ 4: cmpl $(HI_TEXT(hi_sysenter)),(%esp) jne hi_debug_trap /* * eip/cs/flags have been pushed on intr stack * We have to switch to pcb stack and copy eflags. * Note: setting the cs selector to SYSENTER_TF_CS * will cause the return to user path to take the iret path so * that eflags (containing the trap bit) is set atomically. * In unix_syscall this is tested so that we'll rewind the pc * to account for with sysenter or int entry. */ addl $8,%esp /* remove eip/cs */ pushl %ecx /* save %ecx */ movl 8(%esp),%ecx /* top of intr stack -> pcb stack */ xchgl %ecx,%esp /* switch to pcb stack */ pushl $(USER_DS) /* ss */ pushl %ss:(%ecx) /* %ecx into uesp slot */ pushl %ss:4(%ecx) /* eflags */ movl %ss:(%ecx),%ecx /* restore %ecx */ pushl $(SYSENTER_TF_CS) /* cs - not SYSENTER_CS for iret path */ jmp hi_sysenter_2 /* continue sysenter entry */ hi_debug_trap: pushl $0 pushl $(T_DEBUG) /* handle as user trap */ pusha /* save the general registers */ movl $ EXT(lo_alltraps),%ebx jmp enter_lohandler /* * 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(hi_gen_prot) pushl $(T_GENERAL_PROTECTION) /* indicate fault type */ jmp trap_check_kernel_exit /* check for kernel exit sequence */ Entry(hi_segnp) pushl $(T_SEGMENT_NOT_PRESENT) /* indicate fault type */ trap_check_kernel_exit: testb $3,12(%esp) jnz hi_take_trap /* trap was from kernel mode, so */ /* check for the kernel exit sequence */ cmpl $(HI_TEXT(ret_iret)),8(%esp) /* on IRET? */ je fault_iret cmpl $(HI_TEXT(ret_popl_ds)),8(%esp) /* popping DS? */ je fault_popl_ds cmpl $(HI_TEXT(ret_popl_es)),8(%esp) /* popping ES? */ je fault_popl_es cmpl $(HI_TEXT(ret_popl_fs)),8(%esp) /* popping FS? */ je fault_popl_fs cmpl $(HI_TEXT(ret_popl_gs)),8(%esp) /* popping GS? */ je fault_popl_gs hi_take_trap: pusha /* save the general registers */ movl $ EXT(lo_alltraps),%ebx jmp enter_lohandler /* * 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 */ /* now treat as fault from user */ pusha /* save the general registers */ movl $ EXT(lo_alltraps),%ebx jmp enter_lohandler /* * 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_none /* (GS on top of stack) */ push_es: pushl %es /* restore es, */ push_fs: pushl %fs /* restore fs, */ push_gs: pushl %gs /* restore gs. */ push_none: movl %eax,R_TRAPNO(%esp) /* set trap number */ movl %edx,R_ERR(%esp) /* set error code */ /* now treat as fault from user */ /* except that segment registers are */ /* already pushed */ movl $ EXT(lo_alltraps),%ebx jmp enter_lohandler1 .text Entry(lo_ret_to_user) jmp *1f 1: .long HI_TEXT(hi_ret_to_user) Entry(lo_ret_to_kernel) jmp *1f 1: .long HI_TEXT(hi_ret_to_kernel) Entry(hi_remap_etext)