| Current Path : /sys/ia64/ia64/ |
FreeBSD hs32.drive.ne.jp 9.1-RELEASE FreeBSD 9.1-RELEASE #1: Wed Jan 14 12:18:08 JST 2015 root@hs32.drive.ne.jp:/sys/amd64/compile/hs32 amd64 |
| Current File : //sys/ia64/ia64/trap.c |
/*-
* Copyright (c) 2005 Marcel Moolenaar
* 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.
*
* 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: release/9.1.0/sys/ia64/ia64/trap.c 225474 2011-09-11 16:05:09Z kib $");
#include "opt_ddb.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kdb.h>
#include <sys/ktr.h>
#include <sys/sysproto.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/exec.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/sched.h>
#include <sys/smp.h>
#include <sys/vmmeter.h>
#include <sys/sysent.h>
#include <sys/signalvar.h>
#include <sys/syscall.h>
#include <sys/pioctl.h>
#include <sys/ptrace.h>
#include <sys/sysctl.h>
#include <vm/vm.h>
#include <vm/vm_kern.h>
#include <vm/vm_page.h>
#include <vm/vm_map.h>
#include <vm/vm_extern.h>
#include <vm/vm_param.h>
#include <sys/ptrace.h>
#include <machine/cpu.h>
#include <machine/md_var.h>
#include <machine/reg.h>
#include <machine/pal.h>
#include <machine/fpu.h>
#include <machine/efi.h>
#include <machine/pcb.h>
#ifdef SMP
#include <machine/smp.h>
#endif
#include <security/audit/audit.h>
#include <ia64/disasm/disasm.h>
static int print_usertrap = 0;
SYSCTL_INT(_machdep, OID_AUTO, print_usertrap,
CTLFLAG_RW, &print_usertrap, 0, "");
static void break_syscall(struct trapframe *tf);
/*
* EFI-Provided FPSWA interface (Floating Point SoftWare Assist)
*/
extern struct fpswa_iface *fpswa_iface;
static const char *ia64_vector_names[] = {
"VHPT Translation", /* 0 */
"Instruction TLB", /* 1 */
"Data TLB", /* 2 */
"Alternate Instruction TLB", /* 3 */
"Alternate Data TLB", /* 4 */
"Data Nested TLB", /* 5 */
"Instruction Key Miss", /* 6 */
"Data Key Miss", /* 7 */
"Dirty-Bit", /* 8 */
"Instruction Access-Bit", /* 9 */
"Data Access-Bit", /* 10 */
"Break Instruction", /* 11 */
"External Interrupt", /* 12 */
"Reserved 13", /* 13 */
"Reserved 14", /* 14 */
"Reserved 15", /* 15 */
"Reserved 16", /* 16 */
"Reserved 17", /* 17 */
"Reserved 18", /* 18 */
"Reserved 19", /* 19 */
"Page Not Present", /* 20 */
"Key Permission", /* 21 */
"Instruction Access Rights", /* 22 */
"Data Access Rights", /* 23 */
"General Exception", /* 24 */
"Disabled FP-Register", /* 25 */
"NaT Consumption", /* 26 */
"Speculation", /* 27 */
"Reserved 28", /* 28 */
"Debug", /* 29 */
"Unaligned Reference", /* 30 */
"Unsupported Data Reference", /* 31 */
"Floating-point Fault", /* 32 */
"Floating-point Trap", /* 33 */
"Lower-Privilege Transfer Trap", /* 34 */
"Taken Branch Trap", /* 35 */
"Single Step Trap", /* 36 */
"Reserved 37", /* 37 */
"Reserved 38", /* 38 */
"Reserved 39", /* 39 */
"Reserved 40", /* 40 */
"Reserved 41", /* 41 */
"Reserved 42", /* 42 */
"Reserved 43", /* 43 */
"Reserved 44", /* 44 */
"IA-32 Exception", /* 45 */
"IA-32 Intercept", /* 46 */
"IA-32 Interrupt", /* 47 */
"Reserved 48", /* 48 */
"Reserved 49", /* 49 */
"Reserved 50", /* 50 */
"Reserved 51", /* 51 */
"Reserved 52", /* 52 */
"Reserved 53", /* 53 */
"Reserved 54", /* 54 */
"Reserved 55", /* 55 */
"Reserved 56", /* 56 */
"Reserved 57", /* 57 */
"Reserved 58", /* 58 */
"Reserved 59", /* 59 */
"Reserved 60", /* 60 */
"Reserved 61", /* 61 */
"Reserved 62", /* 62 */
"Reserved 63", /* 63 */
"Reserved 64", /* 64 */
"Reserved 65", /* 65 */
"Reserved 66", /* 66 */
"Reserved 67", /* 67 */
};
struct bitname {
uint64_t mask;
const char* name;
};
static void
printbits(uint64_t mask, struct bitname *bn, int count)
{
int i, first = 1;
uint64_t bit;
for (i = 0; i < count; i++) {
/*
* Handle fields wider than one bit.
*/
bit = bn[i].mask & ~(bn[i].mask - 1);
if (bn[i].mask > bit) {
if (first)
first = 0;
else
printf(",");
printf("%s=%ld", bn[i].name,
(mask & bn[i].mask) / bit);
} else if (mask & bit) {
if (first)
first = 0;
else
printf(",");
printf("%s", bn[i].name);
}
}
}
struct bitname psr_bits[] = {
{IA64_PSR_BE, "be"},
{IA64_PSR_UP, "up"},
{IA64_PSR_AC, "ac"},
{IA64_PSR_MFL, "mfl"},
{IA64_PSR_MFH, "mfh"},
{IA64_PSR_IC, "ic"},
{IA64_PSR_I, "i"},
{IA64_PSR_PK, "pk"},
{IA64_PSR_DT, "dt"},
{IA64_PSR_DFL, "dfl"},
{IA64_PSR_DFH, "dfh"},
{IA64_PSR_SP, "sp"},
{IA64_PSR_PP, "pp"},
{IA64_PSR_DI, "di"},
{IA64_PSR_SI, "si"},
{IA64_PSR_DB, "db"},
{IA64_PSR_LP, "lp"},
{IA64_PSR_TB, "tb"},
{IA64_PSR_RT, "rt"},
{IA64_PSR_CPL, "cpl"},
{IA64_PSR_IS, "is"},
{IA64_PSR_MC, "mc"},
{IA64_PSR_IT, "it"},
{IA64_PSR_ID, "id"},
{IA64_PSR_DA, "da"},
{IA64_PSR_DD, "dd"},
{IA64_PSR_SS, "ss"},
{IA64_PSR_RI, "ri"},
{IA64_PSR_ED, "ed"},
{IA64_PSR_BN, "bn"},
{IA64_PSR_IA, "ia"},
};
static void
printpsr(uint64_t psr)
{
printbits(psr, psr_bits, sizeof(psr_bits)/sizeof(psr_bits[0]));
}
struct bitname isr_bits[] = {
{IA64_ISR_CODE, "code"},
{IA64_ISR_VECTOR, "vector"},
{IA64_ISR_X, "x"},
{IA64_ISR_W, "w"},
{IA64_ISR_R, "r"},
{IA64_ISR_NA, "na"},
{IA64_ISR_SP, "sp"},
{IA64_ISR_RS, "rs"},
{IA64_ISR_IR, "ir"},
{IA64_ISR_NI, "ni"},
{IA64_ISR_SO, "so"},
{IA64_ISR_EI, "ei"},
{IA64_ISR_ED, "ed"},
};
static void printisr(uint64_t isr)
{
printbits(isr, isr_bits, sizeof(isr_bits)/sizeof(isr_bits[0]));
}
static void
printtrap(int vector, struct trapframe *tf, int isfatal, int user)
{
printf("\n");
printf("%s %s trap (cpu %d):\n", isfatal? "fatal" : "handled",
user ? "user" : "kernel", PCPU_GET(cpuid));
printf("\n");
printf(" trap vector = 0x%x (%s)\n",
vector, ia64_vector_names[vector]);
printf(" cr.iip = 0x%lx\n", tf->tf_special.iip);
printf(" cr.ipsr = 0x%lx (", tf->tf_special.psr);
printpsr(tf->tf_special.psr);
printf(")\n");
printf(" cr.isr = 0x%lx (", tf->tf_special.isr);
printisr(tf->tf_special.isr);
printf(")\n");
printf(" cr.ifa = 0x%lx\n", tf->tf_special.ifa);
if (tf->tf_special.psr & IA64_PSR_IS) {
printf(" ar.cflg = 0x%lx\n", ia64_get_cflg());
printf(" ar.csd = 0x%lx\n", ia64_get_csd());
printf(" ar.ssd = 0x%lx\n", ia64_get_ssd());
}
printf(" curthread = %p\n", curthread);
if (curthread != NULL)
printf(" pid = %d, comm = %s\n",
curthread->td_proc->p_pid, curthread->td_name);
printf("\n");
}
/*
* We got a trap caused by a break instruction and the immediate was 0.
* This indicates that we may have a break.b with some non-zero immediate.
* The break.b doesn't cause the immediate to be put in cr.iim. Hence,
* we need to disassemble the bundle and return the immediate found there.
* This may be a 0 value anyway. Return 0 for any error condition. This
* will result in a SIGILL, which is pretty much the best thing to do.
*/
static uint64_t
trap_decode_break(struct trapframe *tf)
{
struct asm_bundle bundle;
struct asm_inst *inst;
int slot;
if (!asm_decode(tf->tf_special.iip, &bundle))
return (0);
slot = ((tf->tf_special.psr & IA64_PSR_RI) == IA64_PSR_RI_0) ? 0 :
((tf->tf_special.psr & IA64_PSR_RI) == IA64_PSR_RI_1) ? 1 : 2;
inst = bundle.b_inst + slot;
/*
* Sanity checking: It must be a break instruction and the operand
* that has the break value must be an immediate.
*/
if (inst->i_op != ASM_OP_BREAK ||
inst->i_oper[1].o_type != ASM_OPER_IMM)
return (0);
return (inst->i_oper[1].o_value);
}
void
trap_panic(int vector, struct trapframe *tf)
{
printtrap(vector, tf, 1, TRAPF_USERMODE(tf));
#ifdef KDB
kdb_trap(vector, 0, tf);
#endif
panic("trap");
}
/*
*
*/
int
do_ast(struct trapframe *tf)
{
ia64_disable_intr();
while (curthread->td_flags & (TDF_ASTPENDING|TDF_NEEDRESCHED)) {
ia64_enable_intr();
ast(tf);
ia64_disable_intr();
}
/*
* Keep interrupts disabled. We return r10 as a favor to the EPC
* syscall code so that it can quicky determine if the syscall
* needs to be restarted or not.
*/
return (tf->tf_scratch.gr10);
}
/*
* Trap is called from exception.s to handle most types of processor traps.
*/
/*ARGSUSED*/
void
trap(int vector, struct trapframe *tf)
{
struct proc *p;
struct thread *td;
uint64_t ucode;
int error, sig, user;
ksiginfo_t ksi;
user = TRAPF_USERMODE(tf) ? 1 : 0;
PCPU_INC(cnt.v_trap);
td = curthread;
p = td->td_proc;
ucode = 0;
if (user) {
ia64_set_fpsr(IA64_FPSR_DEFAULT);
td->td_pticks = 0;
td->td_frame = tf;
if (td->td_ucred != p->p_ucred)
cred_update_thread(td);
} else {
KASSERT(cold || td->td_ucred != NULL,
("kernel trap doesn't have ucred"));
#ifdef KDB
if (kdb_active)
kdb_reenter();
#endif
}
sig = 0;
switch (vector) {
case IA64_VEC_VHPT:
/*
* This one is tricky. We should hardwire the VHPT, but
* don't at this time. I think we're mostly lucky that
* the VHPT is mapped.
*/
trap_panic(vector, tf);
break;
case IA64_VEC_ITLB:
case IA64_VEC_DTLB:
case IA64_VEC_EXT_INTR:
/* We never call trap() with these vectors. */
trap_panic(vector, tf);
break;
case IA64_VEC_ALT_ITLB:
case IA64_VEC_ALT_DTLB:
/*
* These should never happen, because regions 0-4 use the
* VHPT. If we get one of these it means we didn't program
* the region registers correctly.
*/
trap_panic(vector, tf);
break;
case IA64_VEC_NESTED_DTLB:
/*
* When the nested TLB handler encounters an unexpected
* condition, it'll switch to the backup stack and transfer
* here. All we need to do is panic.
*/
trap_panic(vector, tf);
break;
case IA64_VEC_IKEY_MISS:
case IA64_VEC_DKEY_MISS:
case IA64_VEC_KEY_PERMISSION:
/*
* We don't use protection keys, so we should never get
* these faults.
*/
trap_panic(vector, tf);
break;
case IA64_VEC_DIRTY_BIT:
case IA64_VEC_INST_ACCESS:
case IA64_VEC_DATA_ACCESS:
/*
* We get here if we read or write to a page of which the
* PTE does not have the access bit or dirty bit set and
* we can not find the PTE in our datastructures. This
* either means we have a stale PTE in the TLB, or we lost
* the PTE in our datastructures.
*/
trap_panic(vector, tf);
break;
case IA64_VEC_BREAK:
if (user) {
ucode = (int)tf->tf_special.ifa & 0x1FFFFF;
if (ucode == 0) {
/*
* A break.b doesn't cause the immediate to be
* stored in cr.iim (and saved in the TF in
* tf_special.ifa). We need to decode the
* instruction to find out what the immediate
* was. Note that if the break instruction
* didn't happen to be a break.b, but any
* other break with an immediate of 0, we
* will do unnecessary work to get the value
* we already had. Not an issue, because a
* break 0 is invalid.
*/
ucode = trap_decode_break(tf);
}
if (ucode < 0x80000) {
/* Software interrupts. */
switch (ucode) {
case 0: /* Unknown error. */
sig = SIGILL;
break;
case 1: /* Integer divide by zero. */
sig = SIGFPE;
ucode = FPE_INTDIV;
break;
case 2: /* Integer overflow. */
sig = SIGFPE;
ucode = FPE_INTOVF;
break;
case 3: /* Range check/bounds check. */
sig = SIGFPE;
ucode = FPE_FLTSUB;
break;
case 6: /* Decimal overflow. */
case 7: /* Decimal divide by zero. */
case 8: /* Packed decimal error. */
case 9: /* Invalid ASCII digit. */
case 10: /* Invalid decimal digit. */
sig = SIGFPE;
ucode = FPE_FLTINV;
break;
case 4: /* Null pointer dereference. */
case 5: /* Misaligned data. */
case 11: /* Paragraph stack overflow. */
sig = SIGSEGV;
break;
default:
sig = SIGILL;
break;
}
} else if (ucode < 0x100000) {
/* Debugger breakpoint. */
tf->tf_special.psr &= ~IA64_PSR_SS;
sig = SIGTRAP;
} else if (ucode == 0x100000) {
break_syscall(tf);
return; /* do_ast() already called. */
} else if (ucode == 0x180000) {
mcontext_t mc;
error = copyin((void*)tf->tf_scratch.gr8,
&mc, sizeof(mc));
if (!error) {
set_mcontext(td, &mc);
return; /* Don't call do_ast()!!! */
}
sig = SIGSEGV;
ucode = tf->tf_scratch.gr8;
} else
sig = SIGILL;
} else {
#ifdef KDB
if (kdb_trap(vector, 0, tf))
return;
panic("trap");
#else
trap_panic(vector, tf);
#endif
}
break;
case IA64_VEC_PAGE_NOT_PRESENT:
case IA64_VEC_INST_ACCESS_RIGHTS:
case IA64_VEC_DATA_ACCESS_RIGHTS: {
vm_offset_t va;
struct vmspace *vm;
vm_map_t map;
vm_prot_t ftype;
int rv;
rv = 0;
va = trunc_page(tf->tf_special.ifa);
if (va >= VM_MAXUSER_ADDRESS) {
/*
* Don't allow user-mode faults for kernel virtual
* addresses, including the gateway page.
*/
if (user)
goto no_fault_in;
map = kernel_map;
} else {
vm = (p != NULL) ? p->p_vmspace : NULL;
if (vm == NULL)
goto no_fault_in;
map = &vm->vm_map;
}
if (tf->tf_special.isr & IA64_ISR_X)
ftype = VM_PROT_EXECUTE;
else if (tf->tf_special.isr & IA64_ISR_W)
ftype = VM_PROT_WRITE;
else
ftype = VM_PROT_READ;
if (map != kernel_map) {
/*
* Keep swapout from messing with us during this
* critical time.
*/
PROC_LOCK(p);
++p->p_lock;
PROC_UNLOCK(p);
/* Fault in the user page: */
rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
PROC_LOCK(p);
--p->p_lock;
PROC_UNLOCK(p);
} else {
/*
* Don't have to worry about process locking or
* stacks in the kernel.
*/
rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
}
if (rv == KERN_SUCCESS)
goto out;
no_fault_in:
if (!user) {
/* Check for copyin/copyout fault. */
if (td != NULL && td->td_pcb->pcb_onfault != 0) {
tf->tf_special.iip =
td->td_pcb->pcb_onfault;
tf->tf_special.psr &= ~IA64_PSR_RI;
td->td_pcb->pcb_onfault = 0;
goto out;
}
trap_panic(vector, tf);
}
ucode = va;
sig = (rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV;
break;
}
case IA64_VEC_GENERAL_EXCEPTION: {
int code;
if (!user)
trap_panic(vector, tf);
code = tf->tf_special.isr & (IA64_ISR_CODE & 0xf0ull);
switch (code) {
case 0x0: /* Illegal Operation Fault. */
sig = ia64_emulate(tf, td);
break;
default:
sig = SIGILL;
break;
}
if (sig == 0)
goto out;
ucode = vector;
break;
}
case IA64_VEC_SPECULATION:
/*
* The branching behaviour of the chk instruction is not
* implemented by the processor. All we need to do is
* compute the target address of the branch and make sure
* that control is transfered to that address.
* We should do this in the IVT table and not by entring
* the kernel...
*/
tf->tf_special.iip += tf->tf_special.ifa << 4;
tf->tf_special.psr &= ~IA64_PSR_RI;
goto out;
case IA64_VEC_NAT_CONSUMPTION:
case IA64_VEC_UNSUPP_DATA_REFERENCE:
if (user) {
ucode = vector;
sig = SIGILL;
} else
trap_panic(vector, tf);
break;
case IA64_VEC_DISABLED_FP: {
if (user)
ia64_highfp_enable(td, tf);
else
trap_panic(vector, tf);
goto out;
}
case IA64_VEC_DEBUG:
case IA64_VEC_SINGLE_STEP_TRAP:
tf->tf_special.psr &= ~IA64_PSR_SS;
if (!user) {
#ifdef KDB
if (kdb_trap(vector, 0, tf))
return;
panic("trap");
#else
trap_panic(vector, tf);
#endif
}
sig = SIGTRAP;
break;
case IA64_VEC_UNALIGNED_REFERENCE:
/*
* If user-land, do whatever fixups, printing, and
* signalling is appropriate (based on system-wide
* and per-process unaligned-access-handling flags).
*/
if (user) {
sig = unaligned_fixup(tf, td);
if (sig == 0)
goto out;
ucode = tf->tf_special.ifa; /* VA */
} else {
/* Check for copyin/copyout fault. */
if (td != NULL && td->td_pcb->pcb_onfault != 0) {
tf->tf_special.iip =
td->td_pcb->pcb_onfault;
tf->tf_special.psr &= ~IA64_PSR_RI;
td->td_pcb->pcb_onfault = 0;
goto out;
}
trap_panic(vector, tf);
}
break;
case IA64_VEC_FLOATING_POINT_FAULT:
case IA64_VEC_FLOATING_POINT_TRAP: {
struct fpswa_bundle bundle;
struct fpswa_fpctx fpctx;
struct fpswa_ret ret;
char *ip;
u_long fault;
/* Always fatal in kernel. Should never happen. */
if (!user)
trap_panic(vector, tf);
if (fpswa_iface == NULL) {
sig = SIGFPE;
ucode = 0;
break;
}
ip = (char *)tf->tf_special.iip;
if (vector == IA64_VEC_FLOATING_POINT_TRAP &&
(tf->tf_special.psr & IA64_PSR_RI) == 0)
ip -= 16;
error = copyin(ip, &bundle, sizeof(bundle));
if (error) {
sig = SIGBUS; /* EFAULT, basically */
ucode = 0; /* exception summary */
break;
}
/* f6-f15 are saved in exception_save */
fpctx.mask_low = 0xffc0; /* bits 6 - 15 */
fpctx.mask_high = 0;
fpctx.fp_low_preserved = NULL;
fpctx.fp_low_volatile = &tf->tf_scratch_fp.fr6;
fpctx.fp_high_preserved = NULL;
fpctx.fp_high_volatile = NULL;
fault = (vector == IA64_VEC_FLOATING_POINT_FAULT) ? 1 : 0;
/*
* We have the high FP registers disabled while in the
* kernel. Enable them for the FPSWA handler only.
*/
ia64_enable_highfp();
/* The docs are unclear. Is Fpswa reentrant? */
ret = fpswa_iface->if_fpswa(fault, &bundle,
&tf->tf_special.psr, &tf->tf_special.fpsr,
&tf->tf_special.isr, &tf->tf_special.pr,
&tf->tf_special.cfm, &fpctx);
ia64_disable_highfp();
/*
* Update ipsr and iip to next instruction. We only
* have to do that for faults.
*/
if (fault && (ret.status == 0 || (ret.status & 2))) {
int ei;
ei = (tf->tf_special.isr >> 41) & 0x03;
if (ei == 0) { /* no template for this case */
tf->tf_special.psr &= ~IA64_ISR_EI;
tf->tf_special.psr |= IA64_ISR_EI_1;
} else if (ei == 1) { /* MFI or MFB */
tf->tf_special.psr &= ~IA64_ISR_EI;
tf->tf_special.psr |= IA64_ISR_EI_2;
} else if (ei == 2) { /* MMF */
tf->tf_special.psr &= ~IA64_ISR_EI;
tf->tf_special.iip += 0x10;
}
}
if (ret.status == 0) {
goto out;
} else if (ret.status == -1) {
printf("FATAL: FPSWA err1 %lx, err2 %lx, err3 %lx\n",
ret.err1, ret.err2, ret.err3);
panic("fpswa fatal error on fp fault");
} else {
sig = SIGFPE;
ucode = 0; /* XXX exception summary */
break;
}
}
case IA64_VEC_LOWER_PRIVILEGE_TRANSFER:
/*
* The lower-privilege transfer trap is used by the EPC
* syscall code to trigger re-entry into the kernel when the
* process should be single stepped. The problem is that
* there's no way to set single stepping directly without
* using the rfi instruction. So instead we enable the
* lower-privilege transfer trap and when we get here we
* know that the process is about to enter userland (and
* has already lowered its privilege).
* However, there's another gotcha. When the process has
* lowered it's privilege it's still running in the gateway
* page. If we enable single stepping, we'll be stepping
* the code in the gateway page. In and by itself this is
* not a problem, but it's an address debuggers won't know
* anything about. Hence, it can only cause confusion.
* We know that we need to branch to get out of the gateway
* page, so what we do here is enable the taken branch
* trap and just let the process continue. When we branch
* out of the gateway page we'll get back into the kernel
* and then we enable single stepping.
* Since this a rather round-about way of enabling single
* stepping, don't make things even more complicated by
* calling userret() and do_ast(). We do that later...
*/
tf->tf_special.psr &= ~IA64_PSR_LP;
tf->tf_special.psr |= IA64_PSR_TB;
return;
case IA64_VEC_TAKEN_BRANCH_TRAP:
/*
* Don't assume there aren't any branches other than the
* branch that takes us out of the gateway page. Check the
* iip and enable single stepping only when it's an user
* address.
*/
if (tf->tf_special.iip >= VM_MAXUSER_ADDRESS)
return;
tf->tf_special.psr &= ~IA64_PSR_TB;
tf->tf_special.psr |= IA64_PSR_SS;
return;
case IA64_VEC_IA32_EXCEPTION:
case IA64_VEC_IA32_INTERCEPT:
case IA64_VEC_IA32_INTERRUPT:
sig = SIGEMT;
ucode = tf->tf_special.iip;
break;
default:
/* Reserved vectors get here. Should never happen of course. */
trap_panic(vector, tf);
break;
}
KASSERT(sig != 0, ("foo"));
if (print_usertrap)
printtrap(vector, tf, 1, user);
ksiginfo_init(&ksi);
ksi.ksi_signo = sig;
ksi.ksi_code = ucode;
trapsignal(td, &ksi);
out:
if (user) {
userret(td, tf);
mtx_assert(&Giant, MA_NOTOWNED);
do_ast(tf);
}
return;
}
/*
* Handle break instruction based system calls.
*/
void
break_syscall(struct trapframe *tf)
{
uint64_t *bsp, *tfp;
uint64_t iip, psr;
int error, nargs;
/* Save address of break instruction. */
iip = tf->tf_special.iip;
psr = tf->tf_special.psr;
/* Advance to the next instruction. */
tf->tf_special.psr += IA64_PSR_RI_1;
if ((tf->tf_special.psr & IA64_PSR_RI) > IA64_PSR_RI_2) {
tf->tf_special.iip += 16;
tf->tf_special.psr &= ~IA64_PSR_RI;
}
/*
* Copy the arguments on the register stack into the trapframe
* to avoid having interleaved NaT collections.
*/
tfp = &tf->tf_scratch.gr16;
nargs = tf->tf_special.cfm & 0x7f;
bsp = (uint64_t*)(curthread->td_kstack + tf->tf_special.ndirty +
(tf->tf_special.bspstore & 0x1ffUL));
bsp -= (((uintptr_t)bsp & 0x1ff) < (nargs << 3)) ? (nargs + 1): nargs;
while (nargs--) {
*tfp++ = *bsp++;
if (((uintptr_t)bsp & 0x1ff) == 0x1f8)
bsp++;
}
error = syscall(tf);
if (error == ERESTART) {
tf->tf_special.iip = iip;
tf->tf_special.psr = psr;
}
do_ast(tf);
}
int
cpu_fetch_syscall_args(struct thread *td, struct syscall_args *sa)
{
struct proc *p;
struct trapframe *tf;
p = td->td_proc;
tf = td->td_frame;
sa->code = tf->tf_scratch.gr15;
sa->args = &tf->tf_scratch.gr16;
/*
* syscall() and __syscall() are handled the same on
* the ia64, as everything is 64-bit aligned, anyway.
*/
if (sa->code == SYS_syscall || sa->code == SYS___syscall) {
/*
* Code is first argument, followed by actual args.
*/
sa->code = sa->args[0];
sa->args++;
}
if (p->p_sysent->sv_mask)
sa->code &= p->p_sysent->sv_mask;
if (sa->code >= p->p_sysent->sv_size)
sa->callp = &p->p_sysent->sv_table[0];
else
sa->callp = &p->p_sysent->sv_table[sa->code];
sa->narg = sa->callp->sy_narg;
td->td_retval[0] = 0;
td->td_retval[1] = 0;
return (0);
}
#include "../../kern/subr_syscall.c"
/*
* Process a system call.
*
* See syscall.s for details as to how we get here. In order to support
* the ERESTART case, we return the error to our caller. They deal with
* the hairy details.
*/
int
syscall(struct trapframe *tf)
{
struct syscall_args sa;
struct thread *td;
int error;
td = curthread;
td->td_frame = tf;
ia64_set_fpsr(IA64_FPSR_DEFAULT);
tf->tf_scratch.gr10 = EJUSTRETURN;
error = syscallenter(td, &sa);
syscallret(td, error, &sa);
return (error);
}