freebsd-dev/sys/i386/svr4/svr4_machdep.c
Bruce Evans 846ac2266b Clear the single-step flag for signal handlers. This fixes bogus trace
traps on the first instruction of signal handlers.

In trap.c:syscall(), fake a trace trap if the single-step flag was set
on entry to the kernel, not if it will be set on exit from the kernel.
This fixes bogus trace traps after the last instruction of signal handlers.

gdb-4.18 (the version in FreeBSD) still has problems with the program in
the PR.  These seem to be due to bugs in gdb and not in FreeBSD, and are
fixed in gdb-5.1 (the distribution version).

PR:		33262
Tested by:	k Macy <kip_macy@yahoo.com>
MFC after:	1 day
2002-01-10 11:49:55 +00:00

600 lines
14 KiB
C

/*
* Copyright (c) 1998 Mark Newton
* Copyright (c) 1994 Christos Zoulas
* All rights reserved.
*
* 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. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*
* $FreeBSD$
*/
#include <sys/types.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/exec.h>
#include <sys/filedesc.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/signal.h>
#include <sys/signalvar.h>
#include <machine/cpu.h>
#include <machine/cpufunc.h>
#include <machine/psl.h>
#include <machine/reg.h>
#include <machine/specialreg.h>
#include <machine/sysarch.h>
#include <machine/vm86.h>
#include <machine/vmparam.h>
#include <vm/vm.h>
#include <vm/pmap.h>
#include <compat/svr4/svr4.h>
#include <compat/svr4/svr4_types.h>
#include <compat/svr4/svr4_signal.h>
#include <i386/svr4/svr4_machdep.h>
#include <compat/svr4/svr4_ucontext.h>
#include <compat/svr4/svr4_proto.h>
#include <compat/svr4/svr4_util.h>
#undef sigcode
#undef szsigcode
extern int svr4_szsigcode;
extern char svr4_sigcode[];
extern int _udatasel, _ucodesel;
static void svr4_getsiginfo __P((union svr4_siginfo *, int, u_long, caddr_t));
#if !defined(__NetBSD__)
/* taken from /sys/arch/i386/include/psl.h on NetBSD-1.3 */
# define PSL_MBZ 0xffc08028
# define PSL_USERSTATIC (PSL_USER | PSL_MBZ | PSL_IOPL | PSL_NT | PSL_VM | PSL_VIF | PSL_VIP)
# define USERMODE(c, f) (ISPL(c) == SEL_UPL)
#endif
#if defined(__NetBSD__)
void
svr4_setregs(td, epp, stack)
struct thread *td;
struct exec_package *epp;
u_long stack;
{
register struct pcb *pcb = td->td_pcb;
pcb->pcb_savefpu.sv_env.en_cw = __SVR4_NPXCW__;
setregs(td, epp, stack, 0UL);
}
#endif /* __NetBSD__ */
void
svr4_getcontext(td, uc, mask, oonstack)
struct thread *td;
struct svr4_ucontext *uc;
sigset_t *mask;
int oonstack;
{
struct proc *p = td->td_proc;
struct trapframe *tf = td->td_frame;
svr4_greg_t *r = uc->uc_mcontext.greg;
struct svr4_sigaltstack *s = &uc->uc_stack;
#if defined(DONE_MORE_SIGALTSTACK_WORK)
struct sigacts *psp;
struct sigaltstack *sf;
#endif
PROC_LOCK(p);
#if defined(DONE_MORE_SIGALTSTACK_WORK)
psp = p->p_sigacts;
sf = &p->p_sigstk;
#endif
memset(uc, 0, sizeof(struct svr4_ucontext));
uc->uc_link = p->p_emuldata;
/*
* Set the general purpose registers
*/
#ifdef VM86
if (tf->tf_eflags & PSL_VM) {
r[SVR4_X86_GS] = tf->tf_vm86_gs;
r[SVR4_X86_FS] = tf->tf_vm86_fs;
r[SVR4_X86_ES] = tf->tf_vm86_es;
r[SVR4_X86_DS] = tf->tf_vm86_ds;
r[SVR4_X86_EFL] = get_vflags(td);
} else
#endif
{
#if defined(__NetBSD__)
__asm("movl %%gs,%w0" : "=r" (r[SVR4_X86_GS]));
__asm("movl %%fs,%w0" : "=r" (r[SVR4_X86_FS]));
#else
r[SVR4_X86_GS] = rgs();
r[SVR4_X86_FS] = tf->tf_fs;
#endif
r[SVR4_X86_ES] = tf->tf_es;
r[SVR4_X86_DS] = tf->tf_ds;
r[SVR4_X86_EFL] = tf->tf_eflags;
}
r[SVR4_X86_EDI] = tf->tf_edi;
r[SVR4_X86_ESI] = tf->tf_esi;
r[SVR4_X86_EBP] = tf->tf_ebp;
r[SVR4_X86_ESP] = tf->tf_esp;
r[SVR4_X86_EBX] = tf->tf_ebx;
r[SVR4_X86_EDX] = tf->tf_edx;
r[SVR4_X86_ECX] = tf->tf_ecx;
r[SVR4_X86_EAX] = tf->tf_eax;
r[SVR4_X86_TRAPNO] = tf->tf_trapno;
r[SVR4_X86_ERR] = tf->tf_err;
r[SVR4_X86_EIP] = tf->tf_eip;
r[SVR4_X86_CS] = tf->tf_cs;
r[SVR4_X86_UESP] = 0;
r[SVR4_X86_SS] = tf->tf_ss;
/*
* Set the signal stack
*/
#if defined(DONE_MORE_SIGALTSTACK_WORK)
bsd_to_svr4_sigaltstack(sf, s);
#else
s->ss_sp = (void *)(((u_long) tf->tf_esp) & ~(16384 - 1));
s->ss_size = 16384;
s->ss_flags = 0;
#endif
PROC_UNLOCK(p);
/*
* Set the signal mask
*/
bsd_to_svr4_sigset(mask, &uc->uc_sigmask);
/*
* Set the flags
*/
uc->uc_flags = SVR4_UC_SIGMASK|SVR4_UC_CPU|SVR4_UC_STACK;
}
/*
* Set to ucontext specified. Reset signal mask and
* stack state from context.
* Return to previous pc and psl as specified by
* context left by sendsig. Check carefully to
* make sure that the user has not modified the
* psl to gain improper privileges or to cause
* a machine fault.
*/
int
svr4_setcontext(td, uc)
struct thread *td;
struct svr4_ucontext *uc;
{
#if defined(DONE_MORE_SIGALTSTACK_WORK)
struct sigacts *psp;
#endif
struct proc *p = td->td_proc;
register struct trapframe *tf;
svr4_greg_t *r = uc->uc_mcontext.greg;
struct svr4_sigaltstack *s = &uc->uc_stack;
struct sigaltstack *sf;
sigset_t mask;
PROC_LOCK(p);
#if defined(DONE_MORE_SIGALTSTACK_WORK)
psp = p->p_sigacts;
#endif
sf = &p->p_sigstk;
/*
* XXX:
* Should we check the value of flags to determine what to restore?
* What to do with uc_link?
* What to do with floating point stuff?
* Should we bother with the rest of the registers that we
* set to 0 right now?
*/
if ((uc->uc_flags & SVR4_UC_CPU) == 0)
return 0;
DPRINTF(("svr4_setcontext(%d)\n", p->p_pid));
tf = td->td_frame;
/*
* Restore register context.
*/
#ifdef VM86
#warning "VM86 doesn't work yet, please don't try to use it."
if (r[SVR4_X86_EFL] & PSL_VM) {
tf->tf_vm86_gs = r[SVR4_X86_GS];
tf->tf_vm86_fs = r[SVR4_X86_FS];
tf->tf_vm86_es = r[SVR4_X86_ES];
tf->tf_vm86_ds = r[SVR4_X86_DS];
set_vflags(td, r[SVR4_X86_EFL]);
} else
#endif
{
/*
* Check for security violations. If we're returning to
* protected mode, the CPU will validate the segment registers
* automatically and generate a trap on violations. We handle
* the trap, rather than doing all of the checking here.
*/
if (((r[SVR4_X86_EFL] ^ tf->tf_eflags) & PSL_USERSTATIC) != 0 ||
!USERMODE(r[SVR4_X86_CS], r[SVR4_X86_EFL]))
return (EINVAL);
#if defined(__NetBSD__)
/* %fs and %gs were restored by the trampoline. */
#else
/* %gs was restored by the trampoline. */
tf->tf_fs = r[SVR4_X86_FS];
#endif
tf->tf_es = r[SVR4_X86_ES];
tf->tf_ds = r[SVR4_X86_DS];
tf->tf_eflags = r[SVR4_X86_EFL];
}
tf->tf_edi = r[SVR4_X86_EDI];
tf->tf_esi = r[SVR4_X86_ESI];
tf->tf_ebp = r[SVR4_X86_EBP];
tf->tf_ebx = r[SVR4_X86_EBX];
tf->tf_edx = r[SVR4_X86_EDX];
tf->tf_ecx = r[SVR4_X86_ECX];
tf->tf_eax = r[SVR4_X86_EAX];
tf->tf_trapno = r[SVR4_X86_TRAPNO];
tf->tf_err = r[SVR4_X86_ERR];
tf->tf_eip = r[SVR4_X86_EIP];
tf->tf_cs = r[SVR4_X86_CS];
tf->tf_ss = r[SVR4_X86_SS];
tf->tf_esp = r[SVR4_X86_ESP];
p->p_emuldata = uc->uc_link;
/*
* restore signal stack
*/
if (uc->uc_flags & SVR4_UC_STACK) {
svr4_to_bsd_sigaltstack(s, sf);
}
/*
* restore signal mask
*/
if (uc->uc_flags & SVR4_UC_SIGMASK) {
#if defined(DEBUG_SVR4)
{
int i;
for (i = 0; i < 4; i++)
DPRINTF(("\tuc_sigmask[%d] = %lx\n", i,
uc->uc_sigmask.bits[i]));
}
#endif
svr4_to_bsd_sigset(&uc->uc_sigmask, &mask);
SIG_CANTMASK(mask);
p->p_sigmask = mask;
}
PROC_UNLOCK(p);
return 0; /*EJUSTRETURN;*/
}
static void
svr4_getsiginfo(si, sig, code, addr)
union svr4_siginfo *si;
int sig;
u_long code;
caddr_t addr;
{
si->si_signo = bsd_to_svr4_sig[sig];
si->si_errno = 0;
si->si_addr = addr;
switch (code) {
case T_PRIVINFLT:
si->si_code = SVR4_ILL_PRVOPC;
si->si_trap = SVR4_T_PRIVINFLT;
break;
case T_BPTFLT:
si->si_code = SVR4_TRAP_BRKPT;
si->si_trap = SVR4_T_BPTFLT;
break;
case T_ARITHTRAP:
si->si_code = SVR4_FPE_INTOVF;
si->si_trap = SVR4_T_DIVIDE;
break;
case T_PROTFLT:
si->si_code = SVR4_SEGV_ACCERR;
si->si_trap = SVR4_T_PROTFLT;
break;
case T_TRCTRAP:
si->si_code = SVR4_TRAP_TRACE;
si->si_trap = SVR4_T_TRCTRAP;
break;
case T_PAGEFLT:
si->si_code = SVR4_SEGV_ACCERR;
si->si_trap = SVR4_T_PAGEFLT;
break;
case T_ALIGNFLT:
si->si_code = SVR4_BUS_ADRALN;
si->si_trap = SVR4_T_ALIGNFLT;
break;
case T_DIVIDE:
si->si_code = SVR4_FPE_FLTDIV;
si->si_trap = SVR4_T_DIVIDE;
break;
case T_OFLOW:
si->si_code = SVR4_FPE_FLTOVF;
si->si_trap = SVR4_T_DIVIDE;
break;
case T_BOUND:
si->si_code = SVR4_FPE_FLTSUB;
si->si_trap = SVR4_T_BOUND;
break;
case T_DNA:
si->si_code = SVR4_FPE_FLTINV;
si->si_trap = SVR4_T_DNA;
break;
case T_FPOPFLT:
si->si_code = SVR4_FPE_FLTINV;
si->si_trap = SVR4_T_FPOPFLT;
break;
case T_SEGNPFLT:
si->si_code = SVR4_SEGV_MAPERR;
si->si_trap = SVR4_T_SEGNPFLT;
break;
case T_STKFLT:
si->si_code = SVR4_ILL_BADSTK;
si->si_trap = SVR4_T_STKFLT;
break;
default:
si->si_code = 0;
si->si_trap = 0;
#if defined(DEBUG_SVR4)
printf("sig %d code %ld\n", sig, code);
/* panic("svr4_getsiginfo");*/
#endif
break;
}
}
/*
* Send an interrupt to process.
*
* Stack is set up to allow sigcode stored
* in u. to call routine. After the handler is
* done svr4 will call setcontext for us
* with the user context we just set up, and we
* will return to the user pc, psl.
*/
void
svr4_sendsig(catcher, sig, mask, code)
sig_t catcher;
int sig;
sigset_t *mask;
u_long code;
{
register struct thread *td = curthread;
struct proc *p = td->td_proc;
register struct trapframe *tf;
struct svr4_sigframe *fp, frame;
struct sigacts *psp;
int oonstack;
#if defined(DEBUG_SVR4)
printf("svr4_sendsig(%d)\n", sig);
#endif
PROC_LOCK_ASSERT(p, MA_OWNED);
psp = p->p_sigacts;
tf = td->td_frame;
oonstack = sigonstack(tf->tf_esp);
/*
* Allocate space for the signal handler context.
*/
if ((p->p_flag & P_ALTSTACK) && !oonstack &&
SIGISMEMBER(psp->ps_sigonstack, sig)) {
fp = (struct svr4_sigframe *)(p->p_sigstk.ss_sp +
p->p_sigstk.ss_size - sizeof(struct svr4_sigframe));
p->p_sigstk.ss_flags |= SS_ONSTACK;
} else {
fp = (struct svr4_sigframe *)tf->tf_esp - 1;
}
PROC_UNLOCK(p);
/*
* Build the argument list for the signal handler.
* Notes:
* - we always build the whole argument list, even when we
* don't need to [when SA_SIGINFO is not set, we don't need
* to pass all sf_si and sf_uc]
* - we don't pass the correct signal address [we need to
* modify many kernel files to enable that]
*/
svr4_getcontext(td, &frame.sf_uc, mask, oonstack);
#if defined(DEBUG_SVR4)
printf("obtained ucontext\n");
#endif
svr4_getsiginfo(&frame.sf_si, sig, code, (caddr_t) tf->tf_eip);
#if defined(DEBUG_SVR4)
printf("obtained siginfo\n");
#endif
frame.sf_signum = frame.sf_si.si_signo;
frame.sf_sip = &fp->sf_si;
frame.sf_ucp = &fp->sf_uc;
frame.sf_handler = catcher;
#if defined(DEBUG_SVR4)
printf("sig = %d, sip %p, ucp = %p, handler = %p\n",
frame.sf_signum, frame.sf_sip, frame.sf_ucp, frame.sf_handler);
#endif
if (copyout(&frame, fp, sizeof(frame)) != 0) {
/*
* Process has trashed its stack; give it an illegal
* instruction to halt it in its tracks.
*/
PROC_LOCK(p);
sigexit(td, SIGILL);
/* NOTREACHED */
}
#if defined(__NetBSD__)
/*
* Build context to run handler in.
*/
tf->tf_es = GSEL(GUSERLDT_SEL, SEL_UPL);
tf->tf_ds = GSEL(GUSERLDT_SEL, SEL_UPL);
tf->tf_eip = (int)(((char *)PS_STRINGS) -
svr4_szsigcode);
tf->tf_cs = GSEL(GUSERLDT_SEL, SEL_UPL);
tf->tf_eflags &= ~(PSL_T|PSL_VM|PSL_AC);
tf->tf_esp = (int)fp;
tf->tf_ss = GSEL(GUSERLDT_SEL, SEL_UPL);
#else
tf->tf_esp = (int)fp;
tf->tf_eip = (int)(((char *)PS_STRINGS) - *(p->p_sysent->sv_szsigcode));
tf->tf_eflags &= ~PSL_T;
tf->tf_cs = _ucodesel;
tf->tf_ds = _udatasel;
tf->tf_es = _udatasel;
tf->tf_fs = _udatasel;
load_gs(_udatasel);
tf->tf_ss = _udatasel;
PROC_LOCK(p);
#endif
}
int
svr4_sys_sysarch(td, v)
struct thread *td;
struct svr4_sys_sysarch_args *v;
{
struct svr4_sys_sysarch_args *uap = v;
#if 0 /* USER_LDT */
#if defined(__NetBSD__)
caddr_t sg = stackgap_init(p->p_emul);
#else
caddr_t sg = stackgap_init();
#endif
int error;
#endif
switch (uap->op) {
case SVR4_SYSARCH_FPHW:
return 0;
case SVR4_SYSARCH_DSCR:
#if 0 /* USER_LDT */
#warning "USER_LDT doesn't work - are you sure you want this?"
{
struct i386_set_ldt_args sa, *sap;
struct sys_sysarch_args ua;
struct svr4_ssd ssd;
union descriptor bsd;
if ((error = copyin(SCARG(uap, a1), &ssd,
sizeof(ssd))) != 0) {
printf("Cannot copy arg1\n");
return error;
}
printf("s=%x, b=%x, l=%x, a1=%x a2=%x\n",
ssd.selector, ssd.base, ssd.limit,
ssd.access1, ssd.access2);
/* We can only set ldt's for now. */
if (!ISLDT(ssd.selector)) {
printf("Not an ldt\n");
return EPERM;
}
/* Oh, well we don't cleanup either */
if (ssd.access1 == 0)
return 0;
bsd.sd.sd_lobase = ssd.base & 0xffffff;
bsd.sd.sd_hibase = (ssd.base >> 24) & 0xff;
bsd.sd.sd_lolimit = ssd.limit & 0xffff;
bsd.sd.sd_hilimit = (ssd.limit >> 16) & 0xf;
bsd.sd.sd_type = ssd.access1 & 0x1f;
bsd.sd.sd_dpl = (ssd.access1 >> 5) & 0x3;
bsd.sd.sd_p = (ssd.access1 >> 7) & 0x1;
bsd.sd.sd_xx = ssd.access2 & 0x3;
bsd.sd.sd_def32 = (ssd.access2 >> 2) & 0x1;
bsd.sd.sd_gran = (ssd.access2 >> 3)& 0x1;
sa.start = IDXSEL(ssd.selector);
sa.desc = stackgap_alloc(&sg, sizeof(union descriptor));
sa.num = 1;
sap = stackgap_alloc(&sg,
sizeof(struct i386_set_ldt_args));
if ((error = copyout(&sa, sap, sizeof(sa))) != 0) {
printf("Cannot copyout args\n");
return error;
}
SCARG(&ua, op) = I386_SET_LDT;
SCARG(&ua, parms) = (char *) sap;
if ((error = copyout(&bsd, sa.desc, sizeof(bsd))) != 0) {
printf("Cannot copyout desc\n");
return error;
}
return sys_sysarch(td, &ua, retval);
}
#endif
default:
printf("svr4_sysarch(%d), a1 %p\n", uap->op,
uap->a1);
return 0;
}
}