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BSD 4_4_Lite1 release
[unix-history] / usr / src / sys / sparc / sparc / trap.c
/*
* Copyright (c) 1992, 1993
* The Regents of the University of California. All rights reserved.
*
* This software was developed by the Computer Systems Engineering group
* at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
* contributed to Berkeley.
*
* All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Lawrence Berkeley Laboratory.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)trap.c 8.4 (Berkeley) 9/23/93
*
* from: $Header: trap.c,v 1.34 93/05/28 04:34:50 torek Exp $
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/user.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/resource.h>
#include <sys/signal.h>
#include <sys/wait.h>
#include <sys/syscall.h>
#include <sys/syslog.h>
#ifdef KTRACE
#include <sys/ktrace.h>
#endif
#include <vm/vm_kern.h>
#include <machine/cpu.h>
#include <machine/ctlreg.h>
#include <machine/frame.h>
#include <machine/trap.h>
#define offsetof(s, f) ((int)&((s *)0)->f)
extern int cold;
int rwindow_debug = 0;
/*
* Initial FPU state is all registers == all 1s, everything else == all 0s.
* This makes every floating point register a signalling NaN, with sign bit
* set, no matter how it is interpreted. Appendix N of the Sparc V8 document
* seems to imply that we should do this, and it does make sense.
*/
struct fpstate initfpstate = {
{ ~0, ~0, ~0, ~0, ~0, ~0, ~0, ~0, ~0, ~0, ~0, ~0, ~0, ~0, ~0, ~0,
~0, ~0, ~0, ~0, ~0, ~0, ~0, ~0, ~0, ~0, ~0, ~0, ~0, ~0, ~0, ~0 }
};
/*
* There are more than 100 trap types, but most are unused.
*
* Trap type 0 is taken over as an `Asynchronous System Trap'.
* This is left-over Vax emulation crap that should be fixed.
*/
static const char T[] = "trap";
const char *trap_type[] = {
/* non-user vectors */
"ast", /* 0 */
"text fault", /* 1 */
"illegal instruction", /* 2 */
"privileged instruction",/*3 */
"fp disabled", /* 4 */
"window overflow", /* 5 */
"window underflow", /* 6 */
"alignment fault", /* 7 */
"fp exception", /* 8 */
"data fault", /* 9 */
"tag overflow", /* 0a */
T, T, T, T, T, T, /* 0b..10 */
"level 1 int", /* 11 */
"level 2 int", /* 12 */
"level 3 int", /* 13 */
"level 4 int", /* 14 */
"level 5 int", /* 15 */
"level 6 int", /* 16 */
"level 7 int", /* 17 */
"level 8 int", /* 18 */
"level 9 int", /* 19 */
"level 10 int", /* 1a */
"level 11 int", /* 1b */
"level 12 int", /* 1c */
"level 13 int", /* 1d */
"level 14 int", /* 1e */
"level 15 int", /* 1f */
T, T, T, T, T, T, T, T, /* 20..27 */
T, T, T, T, T, T, T, T, /* 28..2f */
T, T, T, T, T, T, /* 30..35 */
"cp disabled", /* 36 */
T, /* 37 */
T, T, T, T, T, T, T, T, /* 38..3f */
"cp exception", /* 40 */
T, T, T, T, T, T, T, /* 41..47 */
T, T, T, T, T, T, T, T, /* 48..4f */
T, T, T, T, T, T, T, T, /* 50..57 */
T, T, T, T, T, T, T, T, /* 58..5f */
T, T, T, T, T, T, T, T, /* 60..67 */
T, T, T, T, T, T, T, T, /* 68..6f */
T, T, T, T, T, T, T, T, /* 70..77 */
T, T, T, T, T, T, T, T, /* 78..7f */
/* user (software trap) vectors */
"sun syscall", /* 80 */
"breakpoint", /* 81 */
"zero divide", /* 82 */
"flush windows", /* 83 */
"clean windows", /* 84 */
"range check", /* 85 */
"fix align", /* 86 */
"integer overflow", /* 87 */
"kgdb exec", /* 88 */
"syscall" /* 89 */
};
#define N_TRAP_TYPES (sizeof trap_type / sizeof *trap_type)
/*
* Define the code needed before returning to user mode, for
* trap, mem_access_fault, and syscall.
*/
static inline void
userret(struct proc *p, int pc, u_quad_t oticks)
{
int sig;
/* take pending signals */
while ((sig = CURSIG(p)) != 0)
postsig(sig);
p->p_priority = p->p_usrpri;
if (want_ast) {
want_ast = 0;
if (p->p_flag & P_OWEUPC) {
p->p_flag &= ~P_OWEUPC;
ADDUPROF(p);
}
}
if (want_resched) {
/*
* Since we are curproc, clock will normally just change
* our priority without moving us from one queue to another
* (since the running process is not on a queue.)
* If that happened after we put ourselves on the run queue
* but before we switched, we might not be on the queue
* indicated by our priority.
*/
(void) splstatclock();
setrunqueue(p);
p->p_stats->p_ru.ru_nivcsw++;
mi_switch();
(void) spl0();
while ((sig = CURSIG(p)) != 0)
postsig(sig);
}
/*
* If profiling, charge recent system time to the trapped pc.
*/
if (p->p_flag & P_PROFIL)
addupc_task(p, pc, (int)(p->p_sticks - oticks));
curpriority = p->p_priority;
}
/*
* If someone stole the FPU while we were away, do not enable it
* on return. This is not done in userret() above as it must follow
* the ktrsysret() in syscall(). Actually, it is likely that the
* ktrsysret should occur before the call to userret.
*/
static inline void share_fpu(struct proc *p, struct trapframe *tf) {
if ((tf->tf_psr & PSR_EF) != 0 && fpproc != p)
tf->tf_psr &= ~PSR_EF;
}
/*
* Called from locore.s trap handling, for non-MMU-related traps.
* (MMU-related traps go through mem_access_fault, below.)
*/
trap(type, psr, pc, tf)
register unsigned type;
register int psr, pc;
register struct trapframe *tf;
{
register struct proc *p;
register struct pcb *pcb;
register int n;
u_quad_t sticks;
/* This steps the PC over the trap. */
#define ADVANCE (n = tf->tf_npc, tf->tf_pc = n, tf->tf_npc = n + 4)
cnt.v_trap++;
/*
* Generally, kernel traps cause a panic. Any exceptions are
* handled early here.
*/
if (psr & PSR_PS) {
/*
* Storing %fsr in cpu_attach will cause this trap
* even though the fpu has been enabled, if and only
* if there is no FPU.
*/
if (type == T_FPDISABLED && cold) {
ADVANCE;
return;
}
goto dopanic;
}
if ((p = curproc) == NULL)
p = &proc0;
sticks = p->p_sticks;
pcb = &p->p_addr->u_pcb;
p->p_md.md_tf = tf; /* for ptrace/signals */
switch (type) {
default:
if (type < 0x80) {
dopanic:
printf("trap type 0x%x: pc=%x npc=%x psr=%b\n",
type, pc, tf->tf_npc, psr, PSR_BITS);
panic(type < N_TRAP_TYPES ? trap_type[type] : T);
/* NOTREACHED */
}
/* the following message is gratuitous */
/* ... but leave it in until we find anything */
printf("%s[%d]: unimplemented software trap 0x%x\n",
p->p_comm, p->p_pid, type);
trapsignal(p, SIGILL, type);
break;
case T_AST:
break; /* the work is all in userret() */
case T_ILLINST:
trapsignal(p, SIGILL, 0); /* XXX code?? */
break;
case T_PRIVINST:
trapsignal(p, SIGILL, 0); /* XXX code?? */
break;
case T_FPDISABLED: {
register struct fpstate *fs = p->p_md.md_fpstate;
if (fs == NULL) {
fs = malloc(sizeof *fs, M_SUBPROC, M_WAITOK);
*fs = initfpstate;
p->p_md.md_fpstate = fs;
}
/*
* If we have not found an FPU, we have to emulate it.
*/
if (!foundfpu) {
#ifdef notyet
fpu_emulate(p, tf, fs);
break;
#else
trapsignal(p, SIGFPE, 0); /* XXX code?? */
break;
#endif
}
/*
* We may have more FPEs stored up and/or ops queued.
* If they exist, handle them and get out. Otherwise,
* resolve the FPU state, turn it on, and try again.
*/
if (fs->fs_qsize) {
fpu_cleanup(p, fs);
break;
}
if (fpproc != p) { /* we do not have it */
if (fpproc != NULL) /* someone else had it */
savefpstate(fpproc->p_md.md_fpstate);
loadfpstate(fs);
fpproc = p; /* now we do have it */
}
tf->tf_psr |= PSR_EF;
break;
}
case T_WINOF:
if (rwindow_save(p))
sigexit(p, SIGILL);
break;
#define read_rw(src, dst) \
copyin((caddr_t)(src), (caddr_t)(dst), sizeof(struct rwindow))
case T_RWRET:
/*
* T_RWRET is a window load needed in order to rett.
* It simply needs the window to which tf->tf_out[6]
* (%sp) points. There are no user or saved windows now.
* Copy the one from %sp into pcb->pcb_rw[0] and set
* nsaved to -1. If we decide to deliver a signal on
* our way out, we will clear nsaved.
*/
if (pcb->pcb_uw || pcb->pcb_nsaved) panic("trap T_RWRET 1");
if (rwindow_debug)
printf("%s[%d]: rwindow: pcb<-stack: %x\n", p->p_comm, p->p_pid, tf->tf_out[6]);
if (read_rw(tf->tf_out[6], &pcb->pcb_rw[0]))
sigexit(p, SIGILL);
if (pcb->pcb_nsaved) panic("trap T_RWRET 2");
pcb->pcb_nsaved = -1; /* mark success */
break;
case T_WINUF:
/*
* T_WINUF is a real window underflow, from a restore
* instruction. It needs to have the contents of two
* windows---the one belonging to the restore instruction
* itself, which is at its %sp, and the one belonging to
* the window above, which is at its %fp or %i6---both
* in the pcb. The restore's window may still be in
* the cpu; we need to force it out to the stack.
*/
if (rwindow_debug)
printf("%s[%d]: rwindow: T_WINUF 0: pcb<-stack: %x\n",
p->p_comm, p->p_pid, tf->tf_out[6]);
write_user_windows();
if (rwindow_save(p) || read_rw(tf->tf_out[6], &pcb->pcb_rw[0]))
sigexit(p, SIGILL);
if (rwindow_debug)
printf("%s[%d]: rwindow: T_WINUF 1: pcb<-stack: %x\n",
p->p_comm, p->p_pid, pcb->pcb_rw[0].rw_in[6]);
if (read_rw(pcb->pcb_rw[0].rw_in[6], &pcb->pcb_rw[1]))
sigexit(p, SIGILL);
if (pcb->pcb_nsaved) panic("trap T_WINUF");
pcb->pcb_nsaved = -1; /* mark success */
break;
case T_ALIGN:
trapsignal(p, SIGBUS, 0); /* XXX code?? */
break;
case T_FPE:
/*
* Clean up after a floating point exception.
* fpu_cleanup can (and usually does) modify the
* state we save here, so we must `give up' the FPU
* chip context. (The software and hardware states
* will not match once fpu_cleanup does its job, so
* we must not save again later.)
*/
if (p != fpproc)
panic("fpe without being the FP user");
savefpstate(p->p_md.md_fpstate);
fpproc = NULL;
/* tf->tf_psr &= ~PSR_EF; */ /* share_fpu will do this */
fpu_cleanup(p, p->p_md.md_fpstate);
/* fpu_cleanup posts signals if needed */
#if 0 /* ??? really never??? */
ADVANCE;
#endif
break;
case T_TAGOF:
trapsignal(p, SIGEMT, 0); /* XXX code?? */
break;
case T_CPDISABLED:
uprintf("coprocessor instruction\n"); /* XXX */
trapsignal(p, SIGILL, 0); /* XXX code?? */
break;
case T_BREAKPOINT:
trapsignal(p, SIGTRAP, 0);
break;
case T_DIV0:
ADVANCE;
trapsignal(p, SIGFPE, FPE_INTDIV_TRAP);
break;
case T_FLUSHWIN:
write_user_windows();
#ifdef probably_slower_since_this_is_usually_false
if (pcb->pcb_nsaved && rwindow_save(p))
sigexit(p, SIGILL);
#endif
ADVANCE;
break;
case T_CLEANWIN:
uprintf("T_CLEANWIN\n"); /* XXX */
ADVANCE;
break;
case T_RANGECHECK:
uprintf("T_RANGECHECK\n"); /* XXX */
ADVANCE;
trapsignal(p, SIGILL, 0); /* XXX code?? */
break;
case T_FIXALIGN:
uprintf("T_FIXALIGN\n"); /* XXX */
ADVANCE;
break;
case T_INTOF:
uprintf("T_INTOF\n"); /* XXX */
ADVANCE;
trapsignal(p, SIGFPE, FPE_INTOVF_TRAP);
break;
}
userret(p, pc, sticks);
share_fpu(p, tf);
#undef ADVANCE
}
/*
* Save windows from PCB into user stack, and return 0. This is used on
* window overflow pseudo-traps (from locore.s, just before returning to
* user mode) and when ptrace or sendsig needs a consistent state.
* As a side effect, rwindow_save() always sets pcb_nsaved to 0,
* clobbering the `underflow restore' indicator if it was -1.
*
* If the windows cannot be saved, pcb_nsaved is restored and we return -1.
*/
int
rwindow_save(p)
register struct proc *p;
{
register struct pcb *pcb = &p->p_addr->u_pcb;
register struct rwindow *rw = &pcb->pcb_rw[0];
register int i;
i = pcb->pcb_nsaved;
if (i < 0) {
pcb->pcb_nsaved = 0;
return (0);
}
if (i == 0)
return (0);
if(rwindow_debug)
printf("%s[%d]: rwindow: pcb->stack:", p->p_comm, p->p_pid);
do {
if(rwindow_debug)
printf(" %x", rw[1].rw_in[6]);
if (copyout((caddr_t)rw, (caddr_t)rw[1].rw_in[6],
sizeof *rw))
return (-1);
rw++;
} while (--i > 0);
if(rwindow_debug)
printf("\n");
pcb->pcb_nsaved = 0;
return (0);
}
/*
* Kill user windows (before exec) by writing back to stack or pcb
* and then erasing any pcb tracks. Otherwise we might try to write
* the registers into the new process after the exec.
*/
kill_user_windows(p)
struct proc *p;
{
write_user_windows();
p->p_addr->u_pcb.pcb_nsaved = 0;
}
/*
* Called from locore.s trap handling, for synchronous memory faults.
*
* This duplicates a lot of logic in trap() and perhaps should be
* moved there; but the bus-error-register parameters are unique to
* this routine.
*
* Since synchronous errors accumulate during prefetch, we can have
* more than one `cause'. But we do not care what the cause, here;
* we just want to page in the page and try again.
*/
mem_access_fault(type, ser, v, pc, psr, tf)
register unsigned type;
register int ser;
register u_int v;
register int pc, psr;
register struct trapframe *tf;
{
register struct proc *p;
register struct vmspace *vm;
register vm_offset_t va;
register int i, rv, sig = SIGBUS;
vm_prot_t ftype;
int onfault, mmucode;
u_quad_t sticks;
cnt.v_trap++;
if ((p = curproc) == NULL) /* safety check */
p = &proc0;
sticks = p->p_sticks;
/*
* Figure out what to pass the VM code, and ignore the sva register
* value in v on text faults (text faults are always at pc).
* Kernel faults are somewhat different: text faults are always
* illegal, and data faults are extra complex. User faults must
* set p->p_md.md_tf, in case we decide to deliver a signal. Check
* for illegal virtual addresses early since those can induce more
* faults.
*/
if (type == T_TEXTFAULT)
v = pc;
i = (int)v >> PG_VSHIFT;
if (i != 0 && i != -1)
goto fault;
ftype = ser & SER_WRITE ? VM_PROT_READ|VM_PROT_WRITE : VM_PROT_READ;
va = trunc_page(v);
if (psr & PSR_PS) {
extern char Lfsbail[];
if (type == T_TEXTFAULT) {
(void) splhigh();
printf("text fault: pc=%x ser=%b\n", pc, ser, SER_BITS);
panic("kernel fault");
/* NOTREACHED */
}
/*
* If this was an access that we shouldn't try to page in,
* resume at the fault handler without any action.
*/
if (p->p_addr && p->p_addr->u_pcb.pcb_onfault == Lfsbail)
goto kfault;
/*
* During autoconfiguration, faults are never OK unless
* pcb_onfault is set. Once running normally we must allow
* exec() to cause copy-on-write faults to kernel addresses.
*/
if (cold)
goto kfault;
if (va >= KERNBASE) {
if (vm_fault(kernel_map, va, ftype, 0) == KERN_SUCCESS)
return;
goto kfault;
}
} else
p->p_md.md_tf = tf;
/*
* mmu_pagein returns -1 if the page is already valid, in which
* case we have a hard fault; it returns 1 if it loads a segment
* that got bumped out via LRU replacement.
*/
vm = p->p_vmspace;
rv = mmu_pagein(&vm->vm_pmap, va, ser & SER_WRITE ? PG_V|PG_W : PG_V);
if (rv < 0)
goto fault;
if (rv > 0)
goto out;
/* alas! must call the horrible vm code */
rv = vm_fault(&vm->vm_map, (vm_offset_t)va, ftype, FALSE);
/*
* If this was a stack access we keep track of the maximum
* accessed stack size. Also, if vm_fault gets a protection
* failure it is due to accessing the stack region outside
* the current limit and we need to reflect that as an access
* error.
*/
if ((caddr_t)va >= vm->vm_maxsaddr) {
if (rv == KERN_SUCCESS) {
unsigned nss = clrnd(btoc(USRSTACK - va));
if (nss > vm->vm_ssize)
vm->vm_ssize = nss;
} else if (rv == KERN_PROTECTION_FAILURE)
rv = KERN_INVALID_ADDRESS;
}
if (rv == KERN_SUCCESS) {
/*
* pmap_enter() does not enter all requests made from
* vm_fault into the MMU (as that causes unnecessary
* entries for `wired' pages). Instead, we call
* mmu_pagein here to make sure the new PTE gets installed.
*/
(void) mmu_pagein(&vm->vm_pmap, va, 0);
} else {
/*
* Pagein failed. If doing copyin/out, return to onfault
* address. Any other page fault in kernel, die; if user
* fault, deliver SIGBUS or SIGSEGV.
*/
if (rv != KERN_PROTECTION_FAILURE)
sig = SIGSEGV;
fault:
if (psr & PSR_PS) {
kfault:
onfault = p->p_addr ?
(int)p->p_addr->u_pcb.pcb_onfault : 0;
if (!onfault) {
(void) splhigh();
printf("data fault: pc=%x addr=%x ser=%b\n",
pc, v, ser, SER_BITS);
panic("kernel fault");
/* NOTREACHED */
}
tf->tf_pc = onfault;
tf->tf_npc = onfault + 4;
return;
}
trapsignal(p, sig, (u_int)v);
}
out:
if ((psr & PSR_PS) == 0) {
userret(p, pc, sticks);
share_fpu(p, tf);
}
}
/*
* System calls. `pc' is just a copy of tf->tf_pc.
*
* Note that the things labelled `out' registers in the trapframe were the
* `in' registers within the syscall trap code (because of the automatic
* `save' effect of each trap). They are, however, the %o registers of the
* thing that made the system call, and are named that way here.
*
* The `suncompat' parameter actually only exists if COMPAT_SUNOS is defined.
*/
syscall(code, tf, pc, suncompat)
register u_int code;
register struct trapframe *tf;
int pc, suncompat;
{
register int i, nsys, *ap, nap;
register struct sysent *callp;
register struct proc *p;
int error, new;
struct args {
int i[8];
} args;
int rval[2];
u_quad_t sticks;
extern int nsysent;
extern struct pcb *cpcb;
cnt.v_syscall++;
p = curproc;
#ifdef DIAGNOSTIC
if (tf->tf_psr & PSR_PS)
panic("syscall");
if (cpcb != &p->p_addr->u_pcb)
panic("syscall cpcb/ppcb");
if (tf != (struct trapframe *)((caddr_t)cpcb + UPAGES * NBPG) - 1)
panic("syscall trapframe");
#endif
sticks = p->p_sticks;
p->p_md.md_tf = tf;
new = code & (SYSCALL_G7RFLAG | SYSCALL_G2RFLAG);
code &= ~(SYSCALL_G7RFLAG | SYSCALL_G2RFLAG);
#ifdef COMPAT_SUNOS
if (suncompat) {
extern int nsunsys;
extern struct sysent sunsys[];
callp = sunsys, nsys = nsunsys;
} else
#endif
callp = sysent, nsys = nsysent;
/*
* The first six system call arguments are in the six %o registers.
* Any arguments beyond that are in the `argument extension' area
* of the user's stack frame (see <machine/frame.h>).
*
* Check for ``special'' codes that alter this, namely syscall and
* __syscall. The latter takes a quad syscall number, so that other
* arguments are at their natural alignments. Adjust the number
* of ``easy'' arguments as appropriate; we will copy the hard
* ones later as needed.
*/
ap = &tf->tf_out[0];
nap = 6;
switch (code) {
case SYS_syscall:
code = *ap++;
nap--;
break;
case SYS___syscall:
#ifdef COMPAT_SUNOS
if (suncompat)
break;
#endif
code = ap[_QUAD_LOWWORD];
ap += 2;
nap -= 2;
break;
}
/* Callp currently points to syscall, which returns ENOSYS. */
if (code < nsys) {
callp += code;
i = callp->sy_narg;
if (i > nap) { /* usually false */
if (i > 8)
panic("syscall nargs");
error = copyin((caddr_t)tf->tf_out[6] +
offsetof(struct frame, fr_argx),
(caddr_t)&args.i[nap], (i - nap) * sizeof(int));
if (error) {
#ifdef KTRACE
if (KTRPOINT(p, KTR_SYSCALL))
ktrsyscall(p->p_tracep, code,
callp->sy_narg, args.i);
#endif
goto bad;
}
i = nap;
}
copywords(ap, args.i, i * 4);
}
rval[0] = 0;
rval[1] = tf->tf_out[1];
error = (*callp->sy_call)(p, &args, rval);
if (error == 0) {
/*
* If fork succeeded and we are the child, our stack
* has moved and the pointer tf is no longer valid,
* and p is wrong. Compute the new trapframe pointer.
* (The trap frame invariably resides at the
* tippity-top of the u. area.)
*/
p = curproc;
tf = (struct trapframe *)
((caddr_t)p->p_addr + UPAGES * NBPG - sizeof(*tf));
/* this is done earlier: */
/* p->p_md.md_tf = tf; */
tf->tf_out[0] = rval[0];
tf->tf_out[1] = rval[1];
if (new) {
/* jmp %g2 (or %g7, deprecated) on success */
i = tf->tf_global[new & SYSCALL_G2RFLAG ? 2 : 7];
if (i & 3) {
error = EINVAL;
goto bad;
}
} else {
/* old system call convention: clear C on success */
tf->tf_psr &= ~PSR_C; /* success */
i = tf->tf_npc;
}
tf->tf_pc = i;
tf->tf_npc = i + 4;
} else if (error > 0 /*error != ERESTART && error != EJUSTRETURN*/) {
bad:
tf->tf_out[0] = error;
tf->tf_psr |= PSR_C; /* fail */
i = tf->tf_npc;
tf->tf_pc = i;
tf->tf_npc = i + 4;
}
/* else if (error == ERESTART || error == EJUSTRETURN) */
/* nothing to do */
userret(p, pc, sticks);
#ifdef KTRACE
if (KTRPOINT(p, KTR_SYSRET))
ktrsysret(p->p_tracep, code, error, rval[0]);
#endif
share_fpu(p, tf);
}
Continuous source code history from original PDP-7 UNIX to FreeBSD 2, the first fully unencumbered FreeBSD release.