diff options
Diffstat (limited to 'arch/i386/entry.S')
| -rw-r--r-- | arch/i386/entry.S | 545 |
1 files changed, 545 insertions, 0 deletions
diff --git a/arch/i386/entry.S b/arch/i386/entry.S new file mode 100644 index 000000000..d7008a74b --- /dev/null +++ b/arch/i386/entry.S @@ -0,0 +1,545 @@ +/* + * linux/arch/i386/entry.S + * + * Copyright (C) 1991, 1992 Linus Torvalds + */ + +/* + * entry.S contains the system-call and fault low-level handling routines. + * This also contains the timer-interrupt handler, as well as all interrupts + * and faults that can result in a task-switch. + * + * NOTE: This code handles signal-recognition, which happens every time + * after a timer-interrupt and after each system call. + * + * I changed all the .align's to 4 (16 byte alignment), as that's faster + * on a 486. + * + * Stack layout in 'ret_from_system_call': + * ptrace needs to have all regs on the stack. + * if the order here is changed, it needs to be + * updated in fork.c:copy_process, signal.c:do_signal, + * ptrace.c and ptrace.h + * + * 0(%esp) - %ebx + * 4(%esp) - %ecx + * 8(%esp) - %edx + * C(%esp) - %esi + * 10(%esp) - %edi + * 14(%esp) - %ebp + * 18(%esp) - %eax + * 1C(%esp) - %ds + * 20(%esp) - %es + * 24(%esp) - %fs + * 28(%esp) - %gs + * 2C(%esp) - orig_eax + * 30(%esp) - %eip + * 34(%esp) - %cs + * 38(%esp) - %eflags + * 3C(%esp) - %oldesp + * 40(%esp) - %oldss + */ + +#define __ASSEMBLY__ +#include <linux/sys.h> +#include <asm/segment.h> + +EBX = 0x00 +ECX = 0x04 +EDX = 0x08 +ESI = 0x0C +EDI = 0x10 +EBP = 0x14 +EAX = 0x18 +DS = 0x1C +ES = 0x20 +FS = 0x24 +GS = 0x28 +ORIG_EAX = 0x2C +EIP = 0x30 +CS = 0x34 +EFLAGS = 0x38 +OLDESP = 0x3C +OLDSS = 0x40 + +CF_MASK = 0x00000001 +IF_MASK = 0x00000200 +NT_MASK = 0x00004000 +VM_MASK = 0x00020000 + +/* + * these are offsets into the task-struct. + */ +state = 0 +counter = 4 +priority = 8 +signal = 12 +blocked = 16 +flags = 20 +errno = 24 +dbgreg6 = 52 +dbgreg7 = 56 +exec_domain = 60 + +ENOSYS = 38 + +.globl _system_call,_lcall7 +.globl _device_not_available, _coprocessor_error +.globl _divide_error,_debug,_nmi,_int3,_overflow,_bounds,_invalid_op +.globl _double_fault,_coprocessor_segment_overrun +.globl _invalid_TSS,_segment_not_present,_stack_segment +.globl _general_protection,_reserved +.globl _alignment_check,_page_fault +.globl ret_from_sys_call, _sys_call_table + +#define SAVE_ALL \ + cld; \ + push %gs; \ + push %fs; \ + push %es; \ + push %ds; \ + pushl %eax; \ + pushl %ebp; \ + pushl %edi; \ + pushl %esi; \ + pushl %edx; \ + pushl %ecx; \ + pushl %ebx; \ + movl $(KERNEL_DS),%edx; \ + mov %dx,%ds; \ + mov %dx,%es; \ + movl $(USER_DS),%edx; \ + mov %dx,%fs; + +#define RESTORE_ALL \ + cmpw $(KERNEL_CS),CS(%esp); \ + je 1f; \ + movl _current,%eax; \ + movl dbgreg7(%eax),%ebx; \ + movl %ebx,%db7; \ +1: popl %ebx; \ + popl %ecx; \ + popl %edx; \ + popl %esi; \ + popl %edi; \ + popl %ebp; \ + popl %eax; \ + pop %ds; \ + pop %es; \ + pop %fs; \ + pop %gs; \ + addl $4,%esp; \ + iret + +.align 4 +_lcall7: + pushfl # We get a different stack layout with call gates, + pushl %eax # which has to be cleaned up later.. + SAVE_ALL + movl EIP(%esp),%eax # due to call gates, this is eflags, not eip.. + movl CS(%esp),%edx # this is eip.. + movl EFLAGS(%esp),%ecx # and this is cs.. + movl %eax,EFLAGS(%esp) # + movl %edx,EIP(%esp) # Now we move them to their "normal" places + movl %ecx,CS(%esp) # + movl %esp,%eax + movl _current,%edx + pushl %eax + movl exec_domain(%edx),%edx # Get the execution domain + movl 4(%edx),%edx # Get the lcall7 handler for the domain + call *%edx + popl %eax + jmp ret_from_sys_call + +.align 4 +handle_bottom_half: + pushfl + incl _intr_count + sti + call _do_bottom_half + popfl + decl _intr_count + jmp 9f +.align 4 +reschedule: + pushl $ret_from_sys_call + jmp _schedule +.align 4 +_system_call: + pushl %eax # save orig_eax + SAVE_ALL + movl $-ENOSYS,EAX(%esp) + cmpl $(NR_syscalls),%eax + jae ret_from_sys_call + movl _sys_call_table(,%eax,4),%eax + testl %eax,%eax + je ret_from_sys_call + movl _current,%ebx + andl $~CF_MASK,EFLAGS(%esp) # clear carry - assume no errors + movl $0,errno(%ebx) + movl %db6,%edx + movl %edx,dbgreg6(%ebx) # save current hardware debugging status + testb $0x20,flags(%ebx) # PF_TRACESYS + jne 1f + call *%eax + movl %eax,EAX(%esp) # save the return value + movl errno(%ebx),%edx + negl %edx + je ret_from_sys_call + movl %edx,EAX(%esp) + orl $(CF_MASK),EFLAGS(%esp) # set carry to indicate error + jmp ret_from_sys_call +.align 4 +1: call _syscall_trace + movl ORIG_EAX(%esp),%eax + call _sys_call_table(,%eax,4) + movl %eax,EAX(%esp) # save the return value + movl _current,%eax + movl errno(%eax),%edx + negl %edx + je 1f + movl %edx,EAX(%esp) + orl $(CF_MASK),EFLAGS(%esp) # set carry to indicate error +1: call _syscall_trace + + .align 4,0x90 +ret_from_sys_call: + cmpl $0,_intr_count + jne 2f +9: movl _bh_mask,%eax + andl _bh_active,%eax + jne handle_bottom_half + movl EFLAGS(%esp),%eax # check VM86 flag: CS/SS are + testl $(VM_MASK),%eax # different then + jne 1f + cmpw $(KERNEL_CS),CS(%esp) # was old code segment supervisor ? + je 2f +1: sti + orl $(IF_MASK),%eax # these just try to make sure + andl $~NT_MASK,%eax # the program doesn't do anything + movl %eax,EFLAGS(%esp) # stupid + cmpl $0,_need_resched + jne reschedule + movl _current,%eax + cmpl _task,%eax # task[0] cannot have signals + je 2f + cmpl $0,state(%eax) # state + jne reschedule + cmpl $0,counter(%eax) # counter + je reschedule + movl blocked(%eax),%ecx + movl %ecx,%ebx # save blocked in %ebx for signal handling + notl %ecx + andl signal(%eax),%ecx + jne signal_return +2: RESTORE_ALL +.align 4 +signal_return: + movl %esp,%ecx + pushl %ecx + testl $(VM_MASK),EFLAGS(%ecx) + jne v86_signal_return + pushl %ebx + call _do_signal + popl %ebx + popl %ebx + RESTORE_ALL +.align 4 +v86_signal_return: + call _save_v86_state + movl %eax,%esp + pushl %eax + pushl %ebx + call _do_signal + popl %ebx + popl %ebx + RESTORE_ALL + +.align 4 +_divide_error: + pushl $0 # no error code + pushl $_do_divide_error +.align 4,0x90 +error_code: + push %fs + push %es + push %ds + pushl %eax + pushl %ebp + pushl %edi + pushl %esi + pushl %edx + pushl %ecx + pushl %ebx + movl $0,%eax + movl %eax,%db7 # disable hardware debugging... + cld + movl $-1, %eax + xchgl %eax, ORIG_EAX(%esp) # orig_eax (get the error code. ) + xorl %ebx,%ebx # zero ebx + mov %gs,%bx # get the lower order bits of gs + xchgl %ebx, GS(%esp) # get the address and save gs. + pushl %eax # push the error code + lea 4(%esp),%edx + pushl %edx + movl $(KERNEL_DS),%edx + mov %dx,%ds + mov %dx,%es + movl $(USER_DS),%edx + mov %dx,%fs + pushl %eax + movl _current,%eax + movl %db6,%edx + movl %edx,dbgreg6(%eax) # save current hardware debugging status + popl %eax + call *%ebx + addl $8,%esp + jmp ret_from_sys_call + +.align 4 +_coprocessor_error: + pushl $0 + pushl $_do_coprocessor_error + jmp error_code + +.align 4 +_device_not_available: + pushl $-1 # mark this as an int + SAVE_ALL + pushl $ret_from_sys_call + movl %cr0,%eax + testl $0x4,%eax # EM (math emulation bit) + je _math_state_restore + pushl $0 # temporary storage for ORIG_EIP + call _math_emulate + addl $4,%esp + ret + +.align 4 +_debug: + pushl $0 + pushl $_do_debug + jmp error_code + +.align 4 +_nmi: + pushl $0 + pushl $_do_nmi + jmp error_code + +.align 4 +_int3: + pushl $0 + pushl $_do_int3 + jmp error_code + +.align 4 +_overflow: + pushl $0 + pushl $_do_overflow + jmp error_code + +.align 4 +_bounds: + pushl $0 + pushl $_do_bounds + jmp error_code + +.align 4 +_invalid_op: + pushl $0 + pushl $_do_invalid_op + jmp error_code + +.align 4 +_coprocessor_segment_overrun: + pushl $0 + pushl $_do_coprocessor_segment_overrun + jmp error_code + +.align 4 +_reserved: + pushl $0 + pushl $_do_reserved + jmp error_code + +.align 4 +_double_fault: + pushl $_do_double_fault + jmp error_code + +.align 4 +_invalid_TSS: + pushl $_do_invalid_TSS + jmp error_code + +.align 4 +_segment_not_present: + pushl $_do_segment_not_present + jmp error_code + +.align 4 +_stack_segment: + pushl $_do_stack_segment + jmp error_code + +.align 4 +_general_protection: + pushl $_do_general_protection + jmp error_code + +.align 4 +_alignment_check: + pushl $_do_alignment_check + jmp error_code + +.align 4 +_page_fault: + pushl $_do_page_fault + jmp error_code + +.data +.align 4 +_sys_call_table: + .long _sys_setup /* 0 */ + .long _sys_exit + .long _sys_fork + .long _sys_read + .long _sys_write + .long _sys_open /* 5 */ + .long _sys_close + .long _sys_waitpid + .long _sys_creat + .long _sys_link + .long _sys_unlink /* 10 */ + .long _sys_execve + .long _sys_chdir + .long _sys_time + .long _sys_mknod + .long _sys_chmod /* 15 */ + .long _sys_chown + .long _sys_break + .long _sys_stat + .long _sys_lseek + .long _sys_getpid /* 20 */ + .long _sys_mount + .long _sys_umount + .long _sys_setuid + .long _sys_getuid + .long _sys_stime /* 25 */ + .long _sys_ptrace + .long _sys_alarm + .long _sys_fstat + .long _sys_pause + .long _sys_utime /* 30 */ + .long _sys_stty + .long _sys_gtty + .long _sys_access + .long _sys_nice + .long _sys_ftime /* 35 */ + .long _sys_sync + .long _sys_kill + .long _sys_rename + .long _sys_mkdir + .long _sys_rmdir /* 40 */ + .long _sys_dup + .long _sys_pipe + .long _sys_times + .long _sys_prof + .long _sys_brk /* 45 */ + .long _sys_setgid + .long _sys_getgid + .long _sys_signal + .long _sys_geteuid + .long _sys_getegid /* 50 */ + .long _sys_acct + .long _sys_phys + .long _sys_lock + .long _sys_ioctl + .long _sys_fcntl /* 55 */ + .long _sys_mpx + .long _sys_setpgid + .long _sys_ulimit + .long _sys_olduname + .long _sys_umask /* 60 */ + .long _sys_chroot + .long _sys_ustat + .long _sys_dup2 + .long _sys_getppid + .long _sys_getpgrp /* 65 */ + .long _sys_setsid + .long _sys_sigaction + .long _sys_sgetmask + .long _sys_ssetmask + .long _sys_setreuid /* 70 */ + .long _sys_setregid + .long _sys_sigsuspend + .long _sys_sigpending + .long _sys_sethostname + .long _sys_setrlimit /* 75 */ + .long _sys_getrlimit + .long _sys_getrusage + .long _sys_gettimeofday + .long _sys_settimeofday + .long _sys_getgroups /* 80 */ + .long _sys_setgroups + .long _sys_select + .long _sys_symlink + .long _sys_lstat + .long _sys_readlink /* 85 */ + .long _sys_uselib + .long _sys_swapon + .long _sys_reboot + .long _sys_readdir + .long _sys_mmap /* 90 */ + .long _sys_munmap + .long _sys_truncate + .long _sys_ftruncate + .long _sys_fchmod + .long _sys_fchown /* 95 */ + .long _sys_getpriority + .long _sys_setpriority + .long _sys_profil + .long _sys_statfs + .long _sys_fstatfs /* 100 */ + .long _sys_ioperm + .long _sys_socketcall + .long _sys_syslog + .long _sys_setitimer + .long _sys_getitimer /* 105 */ + .long _sys_newstat + .long _sys_newlstat + .long _sys_newfstat + .long _sys_uname + .long _sys_iopl /* 110 */ + .long _sys_vhangup + .long _sys_idle + .long _sys_vm86 + .long _sys_wait4 + .long _sys_swapoff /* 115 */ + .long _sys_sysinfo + .long _sys_ipc + .long _sys_fsync + .long _sys_sigreturn + .long _sys_clone /* 120 */ + .long _sys_setdomainname + .long _sys_newuname + .long _sys_modify_ldt + .long _sys_adjtimex + .long _sys_mprotect /* 125 */ + .long _sys_sigprocmask + .long _sys_create_module + .long _sys_init_module + .long _sys_delete_module + .long _sys_get_kernel_syms /* 130 */ + .long _sys_quotactl + .long _sys_getpgid + .long _sys_fchdir + .long _sys_bdflush + .long _sys_sysfs /* 135 */ + .long _sys_personality + .long 0 /* for afs_syscall */ + .long _sys_setfsuid + .long _sys_setfsgid + .long _sys_llseek /* 140 */ + .space (NR_syscalls-140)*4 |