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synced 2026-05-28 04:12:45 -04:00
MFC: r202900
Merge r203608 from amd64/i386: In syscall(), reread syscall number and arguments after ptracestop(), if debugger modified anything in the process environment.
This commit is contained in:
Marius Strobl
parent
c329abd0d3
commit
73769927ae
1 changed files with 104 additions and 69 deletions
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@ -93,9 +93,18 @@ __FBSDID("$FreeBSD$");
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#include <machine/tsb.h>
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#include <machine/watch.h>
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struct syscall_args {
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u_long code;
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struct sysent *callp;
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register_t args[8];
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register_t *argp;
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int narg;
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};
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void trap(struct trapframe *tf);
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void syscall(struct trapframe *tf);
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static int fetch_syscall_args(struct thread *td, struct syscall_args *sa);
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static int trap_pfault(struct thread *td, struct trapframe *tf);
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extern char copy_fault[];
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@ -525,38 +534,93 @@ trap_pfault(struct thread *td, struct trapframe *tf)
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/* Maximum number of arguments that can be passed via the out registers. */
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#define REG_MAXARGS 6
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static int
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fetch_syscall_args(struct thread *td, struct syscall_args *sa)
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{
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struct trapframe *tf;
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struct proc *p;
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int reg;
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int regcnt;
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int error;
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p = td->td_proc;
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tf = td->td_frame;
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reg = 0;
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regcnt = REG_MAXARGS;
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sa->code = tf->tf_global[1];
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if (p->p_sysent->sv_prepsyscall) {
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#if 0
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(*p->p_sysent->sv_prepsyscall)(tf, sa->args, &sa->code,
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¶ms);
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#endif
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} else if (sa->code == SYS_syscall || sa->code == SYS___syscall) {
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sa->code = tf->tf_out[reg++];
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regcnt--;
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}
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if (p->p_sysent->sv_mask)
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sa->code &= p->p_sysent->sv_mask;
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if (sa->code >= p->p_sysent->sv_size)
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sa->callp = &p->p_sysent->sv_table[0];
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else
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sa->callp = &p->p_sysent->sv_table[sa->code];
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sa->narg = sa->callp->sy_narg;
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KASSERT(sa->narg <= sizeof(sa->args) / sizeof(sa->args[0]),
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("Too many syscall arguments!"));
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error = 0;
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sa->argp = sa->args;
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bcopy(&tf->tf_out[reg], sa->args, sizeof(sa->args[0]) * regcnt);
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if (sa->narg > regcnt)
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error = copyin((void *)(tf->tf_out[6] + SPOFF +
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offsetof(struct frame, fr_pad[6])), &sa->args[regcnt],
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(sa->narg - regcnt) * sizeof(sa->args[0]));
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/*
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* This may result in two records if debugger modified
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* registers or memory during sleep at stop/ptrace point.
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*/
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#ifdef KTRACE
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if (KTRPOINT(td, KTR_SYSCALL))
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ktrsyscall(sa->code, sa->narg, sa->argp);
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#endif
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return (error);
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}
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/*
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* Syscall handler. The arguments to the syscall are passed in the o registers
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* by the caller, and are saved in the trap frame. The syscall number is passed
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* in %g1 (and also saved in the trap frame).
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* Syscall handler
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* The arguments to the syscall are passed in the out registers by the caller,
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* and are saved in the trap frame. The syscall number is passed in %g1 (and
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* also saved in the trap frame).
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*/
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void
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syscall(struct trapframe *tf)
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{
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struct sysent *callp;
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struct syscall_args sa;
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struct thread *td;
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register_t args[8];
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register_t *argp;
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struct proc *p;
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u_long code;
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int reg;
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int regcnt;
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int narg;
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int error;
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td = curthread;
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KASSERT(td != NULL, ("trap: curthread NULL"));
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KASSERT(td->td_proc != NULL, ("trap: curproc NULL"));
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p = td->td_proc;
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PCPU_INC(cnt.v_syscall);
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p = td->td_proc;
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td->td_syscalls++;
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td->td_pticks = 0;
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td->td_frame = tf;
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if (td->td_ucred != p->p_ucred)
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cred_update_thread(td);
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code = tf->tf_global[1];
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if ((p->p_flag & P_TRACED) != 0) {
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PROC_LOCK(p);
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td->td_dbgflags &= ~TDB_USERWR;
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PROC_UNLOCK(p);
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}
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/*
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* For syscalls, we don't want to retry the faulting instruction
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@ -565,97 +629,68 @@ syscall(struct trapframe *tf)
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td->td_pcb->pcb_tpc = tf->tf_tpc;
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TF_DONE(tf);
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reg = 0;
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regcnt = REG_MAXARGS;
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if (p->p_sysent->sv_prepsyscall) {
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/*
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* The prep code is MP aware.
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*/
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#if 0
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(*p->p_sysent->sv_prepsyscall)(tf, args, &code, ¶ms);
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#endif
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} else if (code == SYS_syscall || code == SYS___syscall) {
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code = tf->tf_out[reg++];
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regcnt--;
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}
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if (p->p_sysent->sv_mask)
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code &= p->p_sysent->sv_mask;
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if (code >= p->p_sysent->sv_size)
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callp = &p->p_sysent->sv_table[0];
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else
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callp = &p->p_sysent->sv_table[code];
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narg = callp->sy_narg;
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KASSERT(narg <= sizeof(args) / sizeof(args[0]),
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("Too many syscall arguments!"));
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error = 0;
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argp = args;
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bcopy(&tf->tf_out[reg], args, sizeof(args[0]) * regcnt);
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if (narg > regcnt)
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error = copyin((void *)(tf->tf_out[6] + SPOFF +
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offsetof(struct frame, fr_pad[6])),
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&args[regcnt], (narg - regcnt) * sizeof(args[0]));
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error = fetch_syscall_args(td, &sa);
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CTR5(KTR_SYSC, "syscall: td=%p %s(%#lx, %#lx, %#lx)", td,
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syscallnames[code], argp[0], argp[1], argp[2]);
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#ifdef KTRACE
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if (KTRPOINT(td, KTR_SYSCALL))
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ktrsyscall(code, narg, argp);
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#endif
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td->td_syscalls++;
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syscallnames[sa.code], sa.argp[0], sa.argp[1], sa.argp[2]);
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if (error == 0) {
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td->td_retval[0] = 0;
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td->td_retval[1] = 0;
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STOPEVENT(p, S_SCE, narg); /* MP aware */
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STOPEVENT(p, S_SCE, sa.narg);
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PTRACESTOP_SC(p, td, S_PT_SCE);
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if ((td->td_dbgflags & TDB_USERWR) != 0) {
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/*
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* Reread syscall number and arguments if
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* debugger modified registers or memory.
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*/
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error = fetch_syscall_args(td, &sa);
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if (error != 0)
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goto retval;
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td->td_retval[1] = 0;
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}
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AUDIT_SYSCALL_ENTER(code, td);
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error = (*callp->sy_call)(td, argp);
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AUDIT_SYSCALL_ENTER(sa.code, td);
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error = (*sa.callp->sy_call)(td, sa.argp);
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AUDIT_SYSCALL_EXIT(error, td);
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CTR5(KTR_SYSC, "syscall: p=%p error=%d %s return %#lx %#lx ", p,
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error, syscallnames[code], td->td_retval[0],
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CTR5(KTR_SYSC, "syscall: p=%p error=%d %s return %#lx %#lx",
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p, error, syscallnames[sa.code], td->td_retval[0],
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td->td_retval[1]);
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}
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retval:
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cpu_set_syscall_retval(td, error);
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/*
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* Check for misbehavior.
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*/
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WITNESS_WARN(WARN_PANIC, NULL, "System call %s returning",
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(code >= 0 && code < SYS_MAXSYSCALL) ? syscallnames[code] : "???");
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(sa.code >= 0 && sa.code < SYS_MAXSYSCALL) ?
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syscallnames[sa.code] : "???");
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KASSERT(td->td_critnest == 0,
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("System call %s returning in a critical section",
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(code >= 0 && code < SYS_MAXSYSCALL) ? syscallnames[code] : "???"));
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(sa.code >= 0 && sa.code < SYS_MAXSYSCALL) ?
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syscallnames[sa.code] : "???"));
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KASSERT(td->td_locks == 0,
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("System call %s returning with %d locks held",
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(code >= 0 && code < SYS_MAXSYSCALL) ? syscallnames[code] : "???",
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td->td_locks));
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(sa.code >= 0 && sa.code < SYS_MAXSYSCALL) ?
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syscallnames[sa.code] : "???", td->td_locks));
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/*
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* Handle reschedule and other end-of-syscall issues
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* Handle reschedule and other end-of-syscall issues.
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*/
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userret(td, tf);
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#ifdef KTRACE
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if (KTRPOINT(td, KTR_SYSRET))
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ktrsysret(code, error, td->td_retval[0]);
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ktrsysret(sa.code, error, td->td_retval[0]);
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#endif
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/*
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* This works because errno is findable through the
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* register set. If we ever support an emulation where this
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* is not the case, this code will need to be revisited.
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*/
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STOPEVENT(p, S_SCX, code);
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STOPEVENT(p, S_SCX, sa.code);
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PTRACESTOP_SC(p, td, S_PT_SCX);
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}
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