2 * Copyright (c) 1989, 1990 William F. Jolitz.
3 * Copyright (c) 1990 The Regents of the University of California.
6 * This code is derived from software contributed to Berkeley by
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10 * modification, are permitted provided that the following conditions
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19 * This product includes software developed by the University of
20 * California, Berkeley and its contributors.
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39 * $FreeBSD: src/sys/i386/isa/ipl.s,v 1.32.2.3 2002/05/16 16:03:56 bde Exp $
42 #include <machine/asmacros.h>
43 #include <machine/segments.h>
44 #include <machine/ipl.h>
45 #include <machine/lock.h>
46 #include <machine/psl.h>
47 #include <machine/trap.h>
53 * Vector interrupt control section
55 * fpending - Pending interrupts (set when a masked interrupt occurs)
56 * spending - Pending software interrupts
61 .globl fastunpend_count
62 fastunpend_count: .long 0
70 * - fast interrupts are always called with a critical section
73 * - we release our critical section when scheduling interrupt
74 * or softinterrupt threads in order so they can preempt
75 * (unless we are called manually from a critical section, in
76 * which case there will still be a critical section and
77 * they won't preempt anyway).
79 * - TD_NEST_COUNT prevents splz from nesting too deeply within
80 * itself. It is *not* actually an interrupt nesting count.
81 * PCPU(intr_nesting_level) is an interrupt nesting count.
83 * - We have to be careful in regards to local interrupts
84 * occuring simultaniously with our doreti and splz
91 * Handle return from interrupts, traps and syscalls. This function
92 * checks the cpl for unmasked pending interrupts (fast, normal, or
93 * soft) and schedules them if appropriate, then irets.
95 * If we are in a critical section we cannot run any pending ints
96 * nor can be play with mp_lock.
98 * NOTE: Since SPLs no longer exist, all callers of this function
99 * push $0 for the CPL. HOWEVER, we *STILL* use the cpl mask within
100 * this function to mark fast interrupts which could not be dispatched
101 * do to the unavailability of the BGL.
105 .type doreti,@function
107 FAKE_MCOUNT(bintr) /* init "from" bintr -> doreti */
108 popl %eax /* cpl to restore XXX */
109 movl $0,%eax /* irq mask unavailable due to BGL */
110 movl PCPU(curthread),%ebx
111 cli /* interlock with td_critcount */
112 cmpl $0,PCPU(reqflags) /* short cut if nothing to do */
114 testl $-1,TD_CRITCOUNT(%ebx) /* can't unpend if in critical sec */
116 incl TD_CRITCOUNT(%ebx) /* force all ints to pending */
118 cli /* re-assert cli on loop */
119 movl %eax,%ecx /* irq mask unavailable due to BGL */
122 testl $RQF_IPIQ,PCPU(reqflags)
124 testl $RQF_TIMER,PCPU(reqflags)
127 testl PCPU(fpending),%ecx /* check for an unmasked fast int */
130 movl PCPU(spending),%ecx /* check for a pending software int */
134 testl $RQF_AST_MASK,PCPU(reqflags) /* any pending ASTs? */
136 testl $PSL_VM,TF_EFLAGS(%esp)
138 cmpl $1,in_vm86call /* YYY make per 'cpu'? */
141 /* ASTs are only applicable when returning to userland */
142 testb $SEL_RPL_MASK,TF_CS(%esp)
146 * Nothing left to do, finish up. Interrupts are still disabled.
147 * %eax contains the mask of IRQ's that are not available due to
148 * BGL requirements. We can only clear RQF_INTPEND if *ALL* pending
149 * interrupts have been processed.
151 decl TD_CRITCOUNT(%ebx) /* interlocked with cli */
154 andl $~RQF_INTPEND,PCPU(reqflags)
159 * Restore the segment registers. Since segment register values
160 * can be set from user mode, this can result in a kernel mode
161 * exception. The trap code will revector to the *_fault code
162 * which then sets up a T_PROTFLT signal. If the signal is
163 * sent to userland, sendsig() will automatically clean up all
164 * the segment registers to avoid a loop.
166 .globl doreti_popl_gs
167 .globl doreti_popl_fs
168 .globl doreti_popl_es
169 .globl doreti_popl_ds
171 .globl doreti_syscall_ret
182 addl $3*4,%esp /* xflags, trap, err */
187 * Interrupts are likely disabled due to the above interlock
188 * between cli/iretq. We must enable them before calling any
189 * high level function.
192 .globl doreti_iret_fault
194 subl $3*4,%esp /* xflags, trap, err */
197 .globl doreti_popl_ds_fault
198 doreti_popl_ds_fault:
200 .globl doreti_popl_es_fault
201 doreti_popl_es_fault:
203 .globl doreti_popl_fs_fault
204 doreti_popl_fs_fault:
206 .globl doreti_popl_gs_fault
207 doreti_popl_gs_fault:
209 movl $0,TF_ERR(%esp) /* XXX should be the error code */
210 movl $T_PROTFLT,TF_TRAPNO(%esp)
211 jmp alltraps_with_regs_pushed
214 * FAST interrupt pending. NOTE: stack context holds frame structure
215 * for fast interrupt procedure, do not do random pushes or pops!
219 andl PCPU(fpending),%ecx /* only check fast ints */
221 bsfl %ecx, %ecx /* locate the next dispatchable int */
222 btrl %ecx, PCPU(fpending) /* is it really still pending? */
224 pushl %eax /* save IRQ mask unavailable for BGL */
225 /* NOTE: is also CPL in frame */
226 call dofastunpend /* unpend fast intr %ecx */
231 * SOFT interrupt pending
233 * Temporarily back-out our critical section to allow an interrupt
234 * preempt us when we schedule it. Bump intr_nesting_level to
235 * prevent the switch code from recursing via splz too deeply.
240 bsfl %ecx,%ecx /* locate the next pending softint */
241 btrl %ecx,PCPU(spending) /* make sure its still pending */
243 addl $FIRST_SOFTINT,%ecx /* actual intr number */
246 incl TD_NEST_COUNT(%ebx) /* prevent doreti/splz nesting */
247 decl TD_CRITCOUNT(%ebx) /* so we can preempt */
248 call sched_ithd /* YYY must pull in imasks */
249 incl TD_CRITCOUNT(%ebx)
250 decl TD_NEST_COUNT(%ebx)
256 * AST pending. We clear RQF_AST_SIGNAL automatically, the others
257 * are cleared by the trap as they are processed.
259 * Temporarily back-out our critical section because trap() can be
260 * a long-winded call, and we want to be more syscall-like.
262 * YYY theoretically we can call lwkt_switch directly if all we need
263 * to do is a reschedule.
266 andl $~(RQF_AST_SIGNAL|RQF_AST_UPCALL),PCPU(reqflags)
268 movl %eax,%esi /* save cpl (can't use stack) */
269 movl $T_ASTFLT,TF_TRAPNO(%esp)
270 pushl %esp /* pass frame by reference */
271 decl TD_CRITCOUNT(%ebx)
273 incl TD_CRITCOUNT(%ebx)
275 movl %esi,%eax /* restore cpl for loop */
280 * IPIQ message pending. We clear RQF_IPIQ automatically.
283 movl %eax,%esi /* save cpl (can't use stack) */
284 incl PCPU(intr_nesting_level)
285 andl $~RQF_IPIQ,PCPU(reqflags)
287 subl $8,%esp /* add dummy vec and ppl */
288 pushl %esp /* pass frame by reference */
289 call lwkt_process_ipiq_frame
291 decl PCPU(intr_nesting_level)
292 movl %esi,%eax /* restore cpl for loop */
296 movl %eax,%esi /* save cpl (can't use stack) */
297 incl PCPU(intr_nesting_level)
298 andl $~RQF_TIMER,PCPU(reqflags)
300 subl $8,%esp /* add dummy vec and ppl */
301 pushl %esp /* pass frame by reference */
302 call lapic_timer_process_frame
304 decl PCPU(intr_nesting_level)
305 movl %esi,%eax /* restore cpl for loop */
311 * SPLZ() a C callable procedure to dispatch any unmasked pending
312 * interrupts regardless of critical section nesting. ASTs
313 * are not dispatched.
315 * Use %eax to track those IRQs that could not be processed
316 * due to BGL requirements.
323 movl PCPU(curthread),%ebx
324 incl TD_CRITCOUNT(%ebx)
329 movl %eax,%ecx /* ecx = ~CPL */
332 testl $RQF_IPIQ,PCPU(reqflags)
334 testl $RQF_TIMER,PCPU(reqflags)
337 testl PCPU(fpending),%ecx /* check for an unmasked fast int */
340 movl PCPU(spending),%ecx
344 decl TD_CRITCOUNT(%ebx)
347 * Nothing left to do, finish up. Interrupts are still disabled.
348 * If our mask of IRQs we couldn't process due to BGL requirements
349 * is 0 then there are no pending interrupt sources left and we
350 * can clear RQF_INTPEND.
354 andl $~RQF_INTPEND,PCPU(reqflags)
361 * FAST interrupt pending
365 andl PCPU(fpending),%ecx /* only check fast ints */
367 bsfl %ecx, %ecx /* locate the next dispatchable int */
368 btrl %ecx, PCPU(fpending) /* is it really still pending? */
371 call dofastunpend /* unpend fast intr %ecx */
376 * SOFT interrupt pending
378 * Temporarily back-out our critical section to allow the interrupt
384 bsfl %ecx,%ecx /* locate the next pending softint */
385 btrl %ecx,PCPU(spending) /* make sure its still pending */
387 addl $FIRST_SOFTINT,%ecx /* actual intr number */
390 decl TD_CRITCOUNT(%ebx)
391 incl TD_NEST_COUNT(%ebx) /* prevent doreti/splz nesting */
392 call sched_ithd /* YYY must pull in imasks */
393 incl TD_CRITCOUNT(%ebx)
394 decl TD_NEST_COUNT(%ebx) /* prevent doreti/splz nesting */
401 andl $~RQF_IPIQ,PCPU(reqflags)
404 call lwkt_process_ipiq
409 andl $~RQF_TIMER,PCPU(reqflags)
412 call lapic_timer_process
418 * dofastunpend(%ecx:intr)
420 * A FAST interrupt previously made pending can now be run,
421 * execute it by pushing a dummy interrupt frame and
422 * calling ithread_fast_handler to execute or schedule it.
424 * ithread_fast_handler() returns 0 if it wants us to unmask
425 * further interrupts.
428 pushfl ; /* phys int frame / flags */ \
429 pushl %cs ; /* phys int frame / cs */ \
430 pushl 12(%esp) ; /* original caller eip */ \
431 pushl $0 ; /* dummy error code */ \
432 pushl $0 ; /* dummy trap type */ \
433 pushl $0 ; /* dummy xflags */ \
434 subl $13*4,%esp ; /* pushal + 4 seg regs (dummy) + CPL */ \
440 pushl %ebp /* frame for backtrace */
443 pushl %ecx /* last part of intrframe = intr */
444 incl fastunpend_count
445 pushl %esp /* pass frame by reference */
446 call ithread_fast_handler /* returns 0 to unmask */
447 addl $4,%esp /* remove pointer, now intr on top */
450 movl MachIntrABI + MACHINTR_INTREN, %eax
451 call *%eax /* MachIntrABI.intren(intr) */