diff options
Diffstat (limited to 'sys/i386/isa/ipl.s')
| -rw-r--r-- | sys/i386/isa/ipl.s | 149 |
1 files changed, 21 insertions, 128 deletions
diff --git a/sys/i386/isa/ipl.s b/sys/i386/isa/ipl.s index 93612301fa85..1ee9ace4559e 100644 --- a/sys/i386/isa/ipl.s +++ b/sys/i386/isa/ipl.s @@ -44,7 +44,6 @@ * AT/386 * Vector interrupt control section * - * cpl - Current interrupt disable mask * *_imask - Interrupt masks for various spl*() functions * ipending - Pending interrupts (set when a masked interrupt occurs) */ @@ -53,8 +52,6 @@ ALIGN_DATA /* current priority (all off) */ - .globl _cpl -_cpl: .long HWI_MASK | SWI_MASK .globl _tty_imask _tty_imask: .long SWI_TTY_MASK @@ -71,9 +68,9 @@ _softnet_imask: .long SWI_NET_MASK .globl _softtty_imask _softtty_imask: .long SWI_TTY_MASK -/* pending interrupts blocked by splxxx() */ - .globl _ipending -_ipending: .long 0 +/* pending software interrupts */ + .globl _spending +_spending: .long 0 /* set with bits for which queue to service */ .globl _netisr @@ -100,59 +97,30 @@ _netisrs: _doreti: FAKE_MCOUNT(_bintr) /* init "from" _bintr -> _doreti */ addl $4,%esp /* discard unit number */ - popl %eax /* cpl or cml to restore */ doreti_next: - /* - * Check for pending HWIs and SWIs atomically with restoring cpl - * and exiting. The check has to be atomic with exiting to stop - * (ipending & ~cpl) changing from zero to nonzero while we're - * looking at it (this wouldn't be fatal but it would increase - * interrupt latency). Restoring cpl has to be atomic with exiting - * so that the stack cannot pile up (the nesting level of interrupt - * handlers is limited by the number of bits in cpl). - */ -#ifdef SMP - cli /* early to prevent INT deadlock */ -doreti_next2: -#endif - movl %eax,%ecx - notl %ecx /* set bit = unmasked level */ -#ifndef SMP - cli -#endif - andl _ipending,%ecx /* set bit = unmasked pending INT */ - jne doreti_unpend - movl %eax,_cpl decb _intr_nesting_level /* Check for ASTs that can be handled now. */ testl $AST_PENDING,_astpending - je doreti_exit - testb $SEL_RPL_MASK,TF_CS(%esp) - jne doreti_ast - testl $PSL_VM,TF_EFLAGS(%esp) - je doreti_exit - cmpl $1,_in_vm86call - jne doreti_ast + je doreti_exit /* no AST, exit */ + testb $SEL_RPL_MASK,TF_CS(%esp) /* are we in user mode? */ + jne doreti_ast /* yes, do it now. */ + testl $PSL_VM,TF_EFLAGS(%esp) /* kernel mode */ + je doreti_exit /* and not VM86 mode, defer */ + cmpl $1,_in_vm86call /* are we in a VM86 call? */ + jne doreti_ast /* yes, we can do it */ /* - * doreti_exit - release MP lock, pop registers, iret. + * doreti_exit: release MP lock, pop registers, iret. * - * Note that the syscall trap shotcuts to doreti_syscall_ret. + * Note that the syscall trap shortcuts to doreti_syscall_ret. * The segment register pop is a special case, since it may * fault if (for example) a sigreturn specifies bad segment - * registers. The fault is handled in trap.c + * registers. The fault is handled in trap.c. */ - doreti_exit: MEXITCOUNT -#ifdef SMP - /* release the kernel lock */ - movl $_mp_lock, %edx /* GIANT_LOCK */ - call _MPrellock_edx -#endif /* SMP */ - .globl doreti_popl_fs .globl doreti_syscall_ret doreti_syscall_ret: @@ -170,6 +138,13 @@ doreti_popl_ds: doreti_iret: iret + /* + * doreti_iret_fault and friends. Alternative return code for + * the case where we get a fault in the doreti_exit code + * above. trap() (i386/i386/trap.c) catches this specific + * case, sends the process a signal and continues in the + * corresponding place in the code below. + */ ALIGN_TEXT .globl doreti_iret_fault doreti_iret_fault: @@ -189,93 +164,11 @@ doreti_popl_fs_fault: jmp alltraps_with_regs_pushed ALIGN_TEXT -doreti_unpend: - /* - * Enabling interrupts is safe because we haven't restored cpl yet. - * %ecx contains the next probable ready interrupt (~cpl & ipending) - */ -#ifdef SMP - bsfl %ecx, %ecx /* locate the next dispatchable int */ - lock - btrl %ecx, _ipending /* is it really still pending? */ - jnc doreti_next2 /* some intr cleared memory copy */ - sti /* late to prevent INT deadlock */ -#else - sti - bsfl %ecx,%ecx /* slow, but not worth optimizing */ - btrl %ecx,_ipending - jnc doreti_next /* some intr cleared memory copy */ -#endif /* SMP */ - /* - * Execute handleable interrupt - * - * Set up JUMP to _ihandlers[%ecx] for HWIs. - * Set up CALL of _ihandlers[%ecx] for SWIs. - * This is a bit early for the SMP case - we have to push %ecx and - * %edx, but could push only %ecx and load %edx later. - */ - movl _ihandlers(,%ecx,4),%edx - cmpl $NHWI,%ecx - jae doreti_swi /* software interrupt handling */ - cli /* else hardware int handling */ -#ifdef SMP - movl %eax,_cpl /* same as non-smp case right now */ -#else - movl %eax,_cpl -#endif - MEXITCOUNT -#ifdef APIC_INTR_DIAGNOSTIC - lock - incl CNAME(apic_itrace_doreti)(,%ecx,4) -#ifdef APIC_INTR_DIAGNOSTIC_IRQ - cmpl $APIC_INTR_DIAGNOSTIC_IRQ,%ecx - jne 9f - pushl %eax - pushl %ecx - pushl %edx - pushl $APIC_ITRACE_DORETI - call log_intr_event - addl $4,%esp - popl %edx - popl %ecx - popl %eax -9: -#endif -#endif - jmp *%edx - - ALIGN_TEXT -doreti_swi: - pushl %eax - /* - * At least the SWI_CLOCK handler has to run at a possibly strictly - * lower cpl, so we have to restore - * all the h/w bits in cpl now and have to worry about stack growth. - * The worst case is currently (30 Jan 1994) 2 SWI handlers nested - * in dying interrupt frames and about 12 HWIs nested in active - * interrupt frames. There are only 4 different SWIs and the HWI - * and SWI masks limit the nesting further. - * - * The SMP case is currently the same as the non-SMP case. - */ -#ifdef SMP - orl imasks(,%ecx,4), %eax /* or in imasks */ - movl %eax,_cpl /* set cpl for call */ -#else - orl imasks(,%ecx,4),%eax - movl %eax,_cpl -#endif - call *%edx - popl %eax /* cpl to restore */ - jmp doreti_next - - ALIGN_TEXT doreti_ast: andl $~AST_PENDING,_astpending sti movl $T_ASTFLT,TF_TRAPNO(%esp) - call _trap - subl %eax,%eax /* recover cpl|cml */ + call _ast movb $1,_intr_nesting_level /* for doreti_next to decrement */ jmp doreti_next |