/*
* Architecture-specific unaligned trap handling.
*
* Copyright (C) 1999-2002, 2004 Hewlett-Packard Co
* Stephane Eranian <eranian@hpl.hp.com>
* David Mosberger-Tang <davidm@hpl.hp.com>
*
* 2002/12/09 Fix rotating register handling (off-by-1 error, missing fr-rotation). Fix
* get_rse_reg() to not leak kernel bits to user-level (reading an out-of-frame
* stacked register returns an undefined value; it does NOT trigger a
* "rsvd register fault").
* 2001/10/11 Fix unaligned access to rotating registers in s/w pipelined loops.
* 2001/08/13 Correct size of extended floats (float_fsz) from 16 to 10 bytes.
* 2001/01/17 Add support emulation of unaligned kernel accesses.
*/
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/tty.h>
#include <linux/ratelimit.h>
#include <asm/intrinsics.h>
#include <asm/processor.h>
#include <asm/rse.h>
#include <asm/uaccess.h>
#include <asm/unaligned.h>
extern int die_if_kernel(char *str, struct pt_regs *regs, long err);
#undef DEBUG_UNALIGNED_TRAP
#ifdef DEBUG_UNALIGNED_TRAP
# define DPRINT(a...) do { printk("%s %u: ", __func__, __LINE__); printk (a); } while (0)
# define DDUMP(str,vp,len) dump(str, vp, len)
static void
dump (const char *str, void *vp, size_t len)
{
unsigned char *cp = vp;
int i;
printk("%s", str);
for (i = 0; i < len; ++i)
printk (" %02x", *cp++);
printk("\n");
}
#else
# define DPRINT(a...)
# define DDUMP(str,vp,len)
#endif
#define IA64_FIRST_STACKED_GR 32
#define IA64_FIRST_ROTATING_FR 32
#define SIGN_EXT9 0xffffffffffffff00ul
/*
* sysctl settable hook which tells the kernel whether to honor the
* IA64_THREAD_UAC_NOPRINT prctl. Because this is user settable, we want
* to allow the super user to enable/disable this for security reasons
* (i.e. don't allow attacker to fill up logs with unaligned accesses).
*/
int no_unaligned_warning;
int unaligned_dump_stack;
/*
* For M-unit:
*
* opcode | m | x6 |
* --------|------|---------|
* [40-37] | [36] | [35:30] |
* --------|------|---------|
* 4 | 1 | 6 | = 11 bits
* --------------------------
* However bits [31:30] are not directly useful to distinguish between
* load/store so we can use [35:32] instead, which gives the following
* mask ([40:32]) using 9 bits. The 'e' comes from the fact that we defer
* checking the m-bit until later in the load/store emulation.
*/
#define IA64_OPCODE_MASK 0x1ef
#define IA64_OPCODE_SHIFT 32
/*
* Table C-28 Integer Load/Store
*
* We ignore [35:32]= 0x6, 0x7, 0xE, 0xF
*
* ld8.fill, st8.fill MUST be aligned because the RNATs are based on
* the address (bits [8:3]), so we must failed.
*/
#define LD_OP 0x080
#define LDS_OP 0x081
#define LDA_OP 0x082
#define LDSA_OP 0x083
#define LDBIAS_OP 0x084
#define LDACQ_OP 0x085
/* 0x086, 0x087 are not relevant */
#define LDCCLR_OP 0x088
#define LDCNC_OP 0x089
#define LDCCLRACQ_OP 0x08a
#define ST_OP 0x08c
#define STREL_OP 0x08d
/* 0x08e,0x8f are not relevant */
/*
* Table C-29 Integer Load +Reg
*
* we use the ld->m (bit [36:36]) field to determine whether or not we have
* a load/store of this form.
*/
/*
* Table C-30 Integer Load/Store +Imm
*
* We ignore [35:32]= 0x6, 0x7, 0xE, 0xF
*
* ld8.fill, st8.fill must be aligned because the Nat register are based on
* the address, so we must fail and the program must be fixed.
*/
#define LD_IMM_OP 0x0a0
#define LDS_IMM_OP 0x0a1
#define LDA_IMM_OP 0x0a2
#define LDSA_IMM_OP 0x0a3
#define LDBIAS_IMM_OP 0x0a4
#define LDACQ_IMM_OP 0x0a5
/* 0x0a6, 0xa7 are not relevant */
#define LDCCLR_IMM_OP 0x0a8
#define LDCNC_IMM_OP 0x0a9
#define LDCCLRACQ_IMM_OP 0x0aa
#define ST_IMM_OP 0x0ac
#define STREL_IMM_OP 0x0ad
/* 0x0ae,0xaf are not relevant */
/*
* Table C-32 Floating-point Load/Store
*/
#define LDF_OP 0x0c0
#define LDFS_OP 0x0c1
#define LDFA_OP 0x0c2
#define LDFSA_OP 0x0c3
/* 0x0c6 is irrelevant */
#define LDFCCLR_OP 0x0c8
#define LDFCNC_OP 0x0c9
/* 0x0cb is irrelevant */
#define STF_OP 0x0cc
/*
* Table C-33 Floating-point Load +Reg
*
* we use the ld->m (bit [36:36]) field to determine whether or not we have
* a load/store of this form.
*/
/*
* Table C-34 Floating-point Load/Store +Imm
*/
#define LDF_IMM_OP 0x0e0
#define LDFS_IMM_OP 0x0e1
#define LDFA_IMM_OP 0x0e2
#define LDFSA_IMM_OP 0x0e3
/* 0x0e6 is irrelevant */
#define LDFCCLR_IMM_OP 0x0e8
#define LDFCNC_IMM_OP 0x0e9
#define STF_IMM_OP 0x0ec
typedef struct {
unsigned long qp:6; /* [0:5] */
unsigned long r1:7; /* [6:12] */
unsigned long imm:7; /* [13:19] */
unsigned long r3:7; /* [20:26] */
unsigned long x:1; /* [27:27] */
unsigned long hint:2; /* [28:29] */
unsigned long x6_sz:2; /* [30:31] */
unsigned long x6_op:4; /* [32:35], x6 = x6_sz|x6_op */
unsigned long m:1; /* [36:36] */
unsigned long op:4; /* [37:40] */
unsigned long pad:23; /* [41:63] */
} load_store_t;
typedef enum {
UPD_IMMEDIATE, /* ldXZ r1=[r3],imm(9) */
UPD_REG /* ldXZ r1=[r3],r2 */
} update_t;
/*
* We use tables to keep track of the offsets of registers in the saved state.
* This way we save having big switch/case statements.
*
* We use bit 0 to indicate switch_stack or pt_regs.
* The offset is simply shifted by 1 bit.
* A 2-byte value should be enough to hold any kind of offset
*
* In case the calling convention changes (and thus pt_regs/switch_stack)
* simply use RSW instead of RPT or vice-versa.
*/
#define RPO(x) ((size_t) &((struct pt_regs *)0)->x)
#define RSO(x) ((size_t) &((struct switch_stack *)0)->x)
#define RPT(x) (RPO(x) << 1)
#define RSW(x) (1| RSO(x)<<1)
#define GR_OFFS(x) (gr_info[x]>>1)
#define GR_IN_SW(x) (gr_info[x] & 0x1)
#define FR_OFFS(x) (fr_info[x]>>1)
#define FR_IN_SW(x) (fr_info[x] & 0x1)
static u16 gr_info[32]={
0, /* r0 is read-only : WE SHOULD NEVER GET THIS */
RPT(r1), RPT(r2), RPT(r3),
RSW(r4), RSW(r5), RSW(r6), RSW(r7),
RPT(r8), RPT(r9), RPT(r10), RPT(r11),
RPT(r12), RPT(r13), RPT(r14), RPT(r15),
RPT(r16), RPT(r17), RPT(r18), RPT(r19),
RPT(r20), RPT(r21), RPT(r22), RPT(r23),
RPT(r24), RPT(r25), RPT(r26), RPT(r27),
RPT(r28), RPT(r29), RPT(r30), RPT(r31)
};
static u16 fr_info[32]={
0, /* constant : WE SHOULD NEVER GET THIS */
0, /* constant : WE SHOULD NEVER GET THIS */
RSW(f2), RSW(f3), RSW(f4), RSW(f5),
RPT(f6), RPT(f7), RPT(f8), RPT(f9),
RPT(f10), RPT(f11),
RSW(f12), RSW(f13), RSW(f14),
RSW(f15), RSW(f16), RSW(f17), RSW(f18), RSW(f19),
RSW(f20), RSW(f21), RSW(f22), RSW(f23), RSW(f24),
RSW(f25), RSW(f26), RSW(f27), RSW(f28), RSW(f29),
RSW(f30), RSW(f31)
};
/* Invalidate ALAT entry for integer register REGNO. */
static void
invala_gr (int regno)
{
# define F(reg) case reg: ia64_invala_gr(reg); break
switch (regno) {
F( 0); F( 1); F( 2); F( 3); F( 4); F( 5); F( 6); F( 7);
F( 8); F( 9); F( 10); F( 11); F( 12); F( 13); F( 14); F( 15);
F( 16); F( 17); F( 18); F( 19); F( 20); F( 21); F( 22); F( 23);
F( 24); F( 25); F( 26); F( 27); F( 28); F( 29); F( 30); F( 31);
F( 32); F( 33); F( 34); F( 35); F( 36); F( 37); F( 38); F( 39);
F( 40); F( 41); F( 42); F( 43); F( 44); F( 45); F( 46); F( 47);
F( 48); F( 49); F( 50); F( 51); F( 52); F( 53); F( 54); F( 55);
F( 56); F( 57); F( 58); F( 59); F( 60); F( 61); F( 62); F( 63);
F( 64); F( 65); F( 66); F( 67); F( 68); F( 69); F( 70); F( 71);
F( 72); F( 73); F( 74); F( 75); F( 76); F( 77); F( 78); F( 79);
F( 80); F( 81); F( 82); F( 83); F( 84); F( 85); F( 86); F( 87);
F( 88); F( 89); F( 90); F( 91); F( 92); F( 93); F( 94); F( 95);
F( 96); F( 97); F( 98); F( 99); F(100); F(101); F(102); F(103);
F(104); F(105); F(106); F(107); F(108); F(109); F(110); F(111);
F(112); F(113); F(114); F(115); F(116); F(117); F(118); F(119);
F(120); F(121); F(122); F(123); F(124); F(125); F(126); F(127);
}
# undef F
}
/* Invalidate ALAT entry for floating-point register REGNO. */
static void
invala_fr (int regno)
{
# define F(reg) case reg: ia64_invala_fr(reg); break
switch (regno) {
F( 0); F( 1); F( 2); F( 3); F( 4); F( 5); F( 6); F( 7);
F( 8); F( 9); F( 10); F( 11); F( 12); F( 13); F( 14); F( 15);
F( 16); F( 17); F( 18); F( 19); F( 20); F( 21); F( 22); F( 23);
F( 24); F( 25); F( 26); F( 27); F( 28); F( 29); F( 30); F( 31);
F( 32); F( 33); F( 34); F( 35); F( 36); F( 37); F( 38); F( 39);
F( 40); F( 41); F( 42); F( 43); F( 44); F( 45); F( 46); F( 47);
F( 48); F( 49); F( 50); F( 51); F( 52); F( 53); F( 54); F( 55);
F( 56); F( 57); F( 58); F( 59); F( 60); F( 61); F( 62); F( 63);
F( 64); F( 65); F( 66); F( 67); F( 68); F( 69); F( 70); F( 71);
F( 72); F( 73); F( 74); F( 75); F( 76); F( 77); F( 78); F( 79);
F( 80); F( 81); F( 82); F( 83); F( 84); F( 85); F( 86); F( 87);
F( 88); F( 89); F( 90); F( 91); F( 92); F( 93); F( 94); F( 95);
F( 96); F( 97); F( 98); F( 99); F(100); F(101); F(102); F(103);
F(104); F(105); F(106); F(107); F(108); F(109); F(110); F(111);
F(112); F(113); F(114); F(115); F(116); F(117); F(118); F(119);
F(120); F(121); F(122); F(123); F(124); F(125); F(126); F(127);
}
# undef F
}
static inline unsigned long
rotate_reg (unsigned long sor, unsigned long rrb, unsigned long reg)
{
reg += rrb;
if (reg >= sor)
reg -= sor;
return reg;
}
static void
set_rse_reg (struct pt_regs *regs, unsigned long r1, unsigned long val, int nat)
{
struct switch_stack *sw = (struct switch_stack *) regs - 1;
unsigned long *bsp, *bspstore, *addr, *rnat_addr, *ubs_end;
unsigned long *kbs = (void *) current + IA64_RBS_OFFSET;
unsigned long rnats, nat_mask;
unsigned long on_kbs;
long sof = (regs->cr_ifs) & 0x7f;
long sor = 8 * ((regs->cr_ifs >> 14) & 0xf);
long rrb_gr = (regs->cr_ifs >> 18) & 0x7f;
long ridx = r1 - 32;
if (ridx >= sof) {
/* this should never happen, as the "rsvd register fault" has higher priority */
DPRINT("ignoring write to r%lu; only %lu registers are allocated!\n", r1, sof);
return;
}
if (ridx < sor)
ridx = rotate_reg(sor, rrb_gr, ridx);
DPRINT("r%lu, sw.bspstore=%lx pt.bspstore=%lx sof=%ld sol=%ld ridx=%ld\n",
r1, sw->ar_bspstore, regs->ar_bspstore, sof, (regs->cr_ifs >> 7) & 0x7f, ridx);
on_kbs = ia64_rse_num_regs(kbs, (unsigned long *) sw->ar_bspstore);
addr = ia64_rse_skip_regs((unsigned long *) sw->ar_bspstore, -sof + ridx);
if (addr >= kbs) {
/* the register is on the kernel backing store: easy... */
rnat_addr = ia64_rse_rnat_addr(addr);
if ((unsigned long) rnat_addr >= sw->ar_bspstore)
rnat_addr = &sw->ar_rnat;
nat_mask = 1UL << ia64_rse_slot_num(addr);
*addr = val;
if (nat)
*rnat_addr |= nat_mask;
else
*rnat_addr &= ~nat_mask;
return;
}
if (!user_stack(current, regs)) {
DPRINT("ignoring kernel write to r%lu; register isn't on the kernel RBS!", r1);
return;
}
bspstore = (unsigned long *)regs->ar_bspstore;
ubs_end = ia64_rse_skip_regs(bspstore, on_kbs);
bsp = ia64_rse_skip_regs(ubs_end, -sof);
addr = ia64_rse_skip_regs(bsp, ridx);
DPRINT("ubs_end=%p bsp=%p addr=%p\n", (void *) ubs_end, (void *) bsp, (void *) addr);
ia64_poke(current, sw, (unsigned long) ubs_end, (unsigned long) addr, val);
rnat_addr = ia64_rse_rnat_addr(addr);
ia64_peek(current, sw, (unsigned long) ubs_end, (unsigned long) rnat_addr, &rnats);
DPRINT("rnat @%p = 0x%lx nat=%d old nat=%ld\n",
(void *) rnat_addr, rnats, nat, (rnats >> ia64_rse_slot_num(addr)) & 1);
nat_mask = 1UL << ia64_rse_slot_num(addr);
if (nat)
rnats |= nat_mask;
else
rnats &= ~nat_mask;
ia64_poke(current, sw, (unsigned long) ubs_end, (unsigned long) rnat_addr, rnats);
DPRINT("rnat changed to @%p = 0x%lx\n", (void *) rnat_addr, rnats);
}
static void
get_rse_reg (struct pt_regs *regs, unsigned long r1, unsigned long *val, int *nat)
{
struct switch_stack *sw = (struct switch_stack *) regs - 1;
unsigned long *bsp, *addr, *rnat_addr, *ubs_end, *bspstore;
unsigned long *kbs = (void *) current + IA64_RBS_OFFSET;
unsigned long rnats, nat_mask;
unsigned long on_kbs;
long sof = (regs->cr_ifs) & 0x7f;
long sor = 8 * ((regs->cr_ifs >> 14) & 0xf);
long rrb_gr = (regs->cr_ifs >> 18) & 0x7f;
long ridx = r1 - 32;
if (ridx >= sof) {
/* read of out-of-frame register returns an undefined value; 0 in our case. */
DPRINT("ignoring read from r%lu; only %lu registers are allocated!\n", r1, sof);
goto fail;
}
if (ridx < sor)
ridx = rotate_reg(sor, rrb_gr, ridx);
DPRINT("r%lu, sw.bspstore=%lx pt.bspstore=%lx sof=%ld sol=%ld ridx=%ld\n",
r1, sw->ar_bspstore, regs->ar_bspstore, sof, (regs->cr_ifs >> 7) & 0x7f, ridx);
on_kbs = ia64_rse_num_regs(kbs, (unsigned long *) sw->ar_bspstore);
addr = ia64_rse_skip_regs((unsigned long *) sw->ar_bspstore, -sof + ridx);
if (addr >= kbs) {
/* the register is on the kernel backing store: easy... */
*val = *addr;
if (nat) {
rnat_addr = ia64_rse_rnat_addr(addr);
if ((unsigned long) rnat_addr >= sw->ar_bspstore)
rnat_addr = &sw->ar_rnat;
nat_mask = 1UL << ia64_rse_slot_num(addr);
*nat = (*rnat_addr & nat_mask) != 0;
}
return;
}
if (!user_stack(current, regs)) {
DPRINT("ignoring kernel read of r%lu; register isn't on the RBS!", r1);
goto fail;
}
bspstore = (unsigned long *)regs->ar_bspstore;
ubs_end = ia64_rse_skip_regs(bspstore, on_kbs);
bsp = ia64_rse_skip_regs(ubs_end, -sof);
addr = ia64_rse_skip_regs(bsp, ridx);
DPRINT("ubs_end=%p bsp=%p addr=%p\n", (void *) ubs_end, (void *) bsp, (void *) addr);
ia64_peek(current, sw, (unsigned long) ubs_end, (unsigned long) addr, val);
if (nat) {
rnat_addr = ia64_rse_rnat_addr(addr);
nat_mask = 1UL << ia64_rse_slot_num(addr);
DPRINT("rnat @%p = 0x%lx\n", (void *) rnat_addr, rnats);
ia64_peek(current, sw, (unsigned long) ubs_end, (unsigned long) rnat_addr, &rnats);
*nat = (rnats & nat_mask) != 0;
}
return;
fail:
*val = 0;
if (nat)
*nat = 0;
return;
}
static void
setreg (unsigned long regnum, unsigned long val, int nat, struct pt_regs *regs)
{
struct switch_stack *sw = (struct switch_stack *) regs - 1;
unsigned long addr;
unsigned long bitmask;
unsigned long *unat;
/*
* First takes care of stacked registers
*/
if (regnum >= IA64_FIRST_STACKED_GR) {
set_rse_reg(regs, regnum, val, nat);
return;
}
/*
* Using r0 as a target raises a General Exception fault which has higher priority
* than the Unaligned Reference fault.
*/
/*
* Now look at registers in [0-31] range and init correct UNAT
*/
if (GR_IN_SW(regnum)) {
addr = (unsigned long)sw;
unat = &sw->ar_unat;
} else {
addr = (unsigned long)regs;
unat = &sw->caller_unat;
}
DPRINT("tmp_base=%lx switch_stack=%s offset=%d\n",
addr, unat==&sw->ar_unat ? "yes":"no", GR_OFFS(regnum));
/*
* add offset from base of struct
* and do it !
*/
addr += GR_OFFS(regnum);
*(unsigned long *)addr = val;
/*
* We need to clear the corresponding UNAT bit to fully emulate the load
* UNAT bit_pos = GR[r3]{8:3} form EAS-2.4
*/
bitmask = 1UL << (addr >> 3 & 0x3f);
DPRINT("*0x%lx=0x%lx NaT=%d prev_unat @%p=%lx\n", addr, val, nat, (void *) unat, *unat);
if (nat) {
*unat |= bitmask;
} else {
*unat &= ~bitmask;
}
DPRINT("*0x%lx=0x%lx NaT=%d new unat: %p=%lx\n", addr, val, nat, (void *) unat,*unat);
}
/*
* Return the (rotated) index for floating point register REGNUM (REGNUM must be in the
* range from 32-127, result is in the range from 0-95.
*/
static inline unsigned long
fph_index (struct pt_regs *regs, long regnum)
{
unsigned long rrb_fr = (regs->cr_ifs >> 25) & 0x7f;
return rotate_reg(96, rrb_fr, (regnum - IA64_FIRST_ROTATING_FR));
}
static void
setfpreg (unsigned long regnum, struct ia64_fpreg *fpval, struct pt_regs *regs)
{
struct switch_stack *sw = (struct switch_stack *)regs - 1;
unsigned long addr;
/*
* From EAS-2.5: FPDisableFault has higher priority than Unaligned
* Fault. Thus, when we get here, we know the partition is enabled.
* To update f32-f127, there are three choices:
*
* (1) save f32-f127 to thread.fph and update the values there
* (2) use a gigantic switch statement to directly access the registers
* (3) generate code on the fly to update the desired register
*
* For now, we are using approach (1).
*/
if (regnum >= IA64_FIRST_ROTATING_FR) {
ia64_sync_fph(current);
current->thread.fph[fph_index(regs, regnum)] = *fpval;
} else {
/*
* pt_regs or switch_stack ?
*/
if (FR_IN_SW(regnum)) {
addr = (unsigned long)sw;
} else {
addr = (unsigned long)regs;
}
DPRINT("tmp_base=%lx offset=%d\n", addr, FR_OFFS(regnum));
addr += FR_OFFS(regnum);
*(struct ia64_fpreg *)addr = *fpval;
/*
* mark the low partition as being used now
*
* It is highly unlikely that this bit is not already set, but
* let's do it for safety.
*/
regs->cr_ipsr |= IA64_PSR_MFL;
}
}
/*
* Those 2 inline functions generate the spilled versions of the constant floating point
* registers which can be used with stfX
*/
static inline void
float_spill_f0 (struct ia64_fpreg *final)
{
ia64_stf_spill(final, 0);
}
static inline void
float_spill_f1 (struct ia64_fpreg *final)
{
ia64_stf_spill(final, 1);
}
static void
getfpreg (unsigned long regnum, struct ia64_fpreg *fpval, struct pt_regs *regs)
{
struct switch_stack *sw = (struct switch_stack *) regs - 1;
unsigned long addr;
/*
* From EAS-2.5: FPDisableFault has higher priority than
* Unaligned Fault. Thus, when we get here, we know the partition is
* enabled.
*
* When regnum > 31, the register is still live and we need to force a save
* to current->thread.fph to get access to it. See discussion in setfpreg()
* for reasons and other ways of doing this.
*/
if (regnum >= IA64_FIRST_ROTATING_FR) {
ia64_flush_fph(current);
*fpval = current->thread.fph[fph_index(regs, regnum)];
} else {
/*
* f0 = 0.0, f1= 1.0. Those registers are constant and are thus
* not saved, we must generate their spilled form on the fly
*/
switch(regnum) {
case 0:
float_spill_f0(fpval);
break;
case 1:
float_spill_f1(fpval);
break;
default:
/*
* pt_regs or switch_stack ?
*/
addr = FR_IN_SW(regnum) ? (unsigned long)sw
: (unsigned long)regs;
DPRINT("is_sw=%d tmp_base=%lx offset=0x%x\n",
FR_IN_SW(regnum), addr, FR_OFFS(regnum));
addr += FR_OFFS(regnum);
*fpval = *(struct ia64_fpreg *)addr;
}
}
}
static void
getreg (unsigned long regnum, unsigned long *val, int *nat, struct pt_regs *regs)
{
struct switch_stack *sw = (struct switch_stack *) regs - 1;
unsigned long addr, *unat;
if (regnum >= IA64_FIRST_STACKED_GR) {
get_rse_reg(regs, regnum, val, nat);
return;
}
/*
* take care of r0 (read-only always evaluate to 0)
*/
if (regnum == 0) {
*val = 0;
if (nat)
*nat = 0;
return;
}
/*
* Now look at registers in [0-31] range and init correct UNAT
*/
if (GR_IN_SW(regnum)) {
addr = (unsigned long)sw;
unat = &sw->ar_unat;
} else {
addr = (unsigned long)regs;
unat = &sw->caller_unat;
}
DPRINT("addr_base=%lx offset=0x%x\n", addr, GR_OFFS(regnum));
addr += GR_OFFS(regnum);
*val = *(unsigned long *)addr;
/*
* do it only when requested
*/
if (nat)
*nat = (*unat >> (addr >> 3 & 0x3f)) & 0x1UL;
}
static void
emulate_load_updates (update_t type, load_store_t ld, struct pt_regs *regs, unsigned long ifa)
{
/*
* IMPORTANT:
* Given the way we handle unaligned speculative loads, we should
* not get to this point in the code but we keep this sanity check,
* just in case.
*/
if (ld.x6_op == 1 || ld.x6_op == 3) {
printk(KERN_ERR "%s: register update on speculative load, error\n", __func__);
if (die_if_kernel("unaligned reference on speculative load with register update\n",
regs, 30))
return;
}
/*
* at this point, we know that the base register to update is valid i.e.,
* it's not r0
*/
if (type == UPD_IMMEDIATE) {
unsigned long imm;
/*
* Load +Imm: ldXZ r1=[r3],imm(9)
*
*
* form imm9: [13:19] contain the first 7 bits
*/
imm = ld.x << 7 | ld.imm;
/*
* sign extend (1+8bits) if m set
*/
if (ld.m) imm |= SIGN_EXT9;
/*
* ifa == r3 and we know that the NaT bit on r3 was clear so
* we can directly use ifa.
*/
ifa += imm;
setreg(ld.r3, ifa, 0, regs);
DPRINT("ld.x=%d ld.m=%d imm=%ld r3=0x%lx\n", ld.x, ld.m, imm, ifa);
} else if (ld.m) {
unsigned long r2;
int nat_r2;
/*
* Load +Reg Opcode: ldXZ r1=[r3],r2
*
* Note: that we update r3 even in the case of ldfX.a
* (where the load does not happen)
*
* The way the load algorithm works, we know that r3 does not
* have its NaT bit set (would have gotten NaT consumption
* before getting the unaligned fault). So we can use ifa
* which equals r3 at this point.
*
* IMPORTANT:
* The above statement holds ONLY because we know that we
* never reach this code when trying to do a ldX.s.
* If we ever make it to here on an ldfX.s then
*/
getreg(ld.imm, &r2, &nat_r2, regs);
ifa += r2;
/*
* propagate Nat r2 -> r3
*/
setreg(ld.r3, ifa, nat_r2, regs);
DPRINT("imm=%d r2=%ld r3=0x%lx nat_r2=%d\n",ld.imm, r2, ifa, nat_r2);
}
}
static int
emulate_load_int (unsigned long ifa, load_store_t ld, struct pt_regs *regs)
{
unsigned int len = 1 << ld.x6_sz;
unsigned long val = 0;
/*
* r0, as target, doesn't need to be checked because Illegal Instruction
* faults have higher priority than unaligned faults.
*
* r0 cannot be found as the base as it would never generate an
* unaligned reference.
*/
/*
* ldX.a we will emulate load and also invalidate the ALAT entry.
* See comment below for explanation on how we handle ldX.a
*/
if (len != 2 && len != 4 && len != 8) {
DPRINT("unknown size: x6=%d\n", ld.x6_sz);
return -1;
}
/* this assumes little-endian byte-order: */
if (copy_from_user(&val, (void __user *) ifa, len))
return -1;
setreg(ld.r1, val, 0, regs);
/*
* check for updates on any kind of loads
*/
if (ld.op == 0x5 || ld.m)
emulate_load_updates(ld.op == 0x5 ? UPD_IMMEDIATE: UPD_REG, ld, regs, ifa);
/*
* handling of various loads (based on EAS2.4):
*
* ldX.acq (ordered load):
* - acquire semantics would have been used, so force fence instead.
*
* ldX.c.clr (check load and clear):
* - if we get to this handler, it's because the entry was not in the ALAT.
* Therefore the operation reverts to a normal load
*
* ldX.c.nc (check load no clear):
* - same as previous one
*
* ldX.c.clr.acq (ordered check load and clear):
* - same as above for c.clr part. The load needs to have acquire semantics. So
* we use the fence semantics which is stronger and thus ensures correctness.
*
* ldX.a (advanced load):
* - suppose ldX.a r1=[r3]. If we get to the unaligned trap it's because the
* address doesn't match requested size alignment. This means that we would
* possibly need more than one load to get the result.
*
* The load part can be handled just like a normal load, however the difficult
* part is to get the right thing into the ALAT. The critical piece of information
* in the base address of the load & size. To do that, a ld.a must be executed,
* clearly any address can be pushed into the table by using ld1.a r1=[r3]. Now
* if we use the same target register, we will be okay for the check.a instruction.
* If we look at the store, basically a stX [r3]=r1 checks the ALAT for any entry
* which would overlap within [r3,r3+X] (the size of the load was store in the
* ALAT). If such an entry is found the entry is invalidated. But this is not good
* enough, take the following example:
* r3=3
* ld4.a r1=[r3]
*
* Could be emulated by doing:
* ld1.a r1=[r3],1
* store to temporary;
* ld1.a r1=[r3],1
* store & shift to temporary;
* ld1.a r1=[r3],1
* store & shift to temporary;
* ld1.a r1=[r3]
* store & shift to temporary;
* r1=temporary
*
* So in this case, you would get the right value is r1 but the wrong info in
* the ALAT. Notice that you could do it in reverse to finish with address 3
* but you would still get the size wrong. To get the size right, one needs to
* execute exactly the same kind of load. You could do it from a aligned
* temporary location, but you would get the address wrong.
*
* So no matter what, it is not possible to emulate an advanced load
* correctly. But is that really critical ?
*
* We will always convert ld.a into a normal load with ALAT invalidated. This
* will enable compiler to do optimization where certain code path after ld.a
* is not required to have ld.c/chk.a, e.g., code path with no intervening stores.
*
* If there is a store after the advanced load, one must either do a ld.c.* or
* chk.a.* to reuse the value stored in the ALAT. Both can "fail" (meaning no
* entry found in ALAT), and that's perfectly ok because:
*
* - ld.c.*, if the entry is not present a normal load is executed
* - chk.a.*, if the entry is not present, execution jumps to recovery code
*
* In either case, the load can be potentially retried in another form.
*
* ALAT must be invalidated for the register (so that chk.a or ld.c don't pick
* up a stale entry later). The register base update MUST also be performed.
*/
/*
* when the load has the .acq completer then
* use ordering fence.
*/
if (ld.x6_op == 0x5 || ld.x6_op == 0xa)
mb();
/*
* invalidate ALAT entry in case of advanced load
*/
if (ld.x6_op == 0x2)
invala_gr(ld.r1);
return 0;
}
static int
emulate_store_int (unsigned long ifa, load_store_t ld, struct pt_regs *regs)
{
unsigned long r2;
unsigned int len = 1 << ld.x6_sz;
/*
* if we get to this handler, Nat bits on both r3 and r2 have already
* been checked. so we don't need to do it
*
* extract the value to be stored
*/
getreg(ld.imm, &r2, NULL, regs);
/*
* we rely on the macros in unaligned.h for now i.e.,
* we let the compiler figure out how to read memory gracefully.
*
* We need this switch/case because the way the inline function
* works. The code is optimized by the compiler and looks like
* a single switch/case.
*/
DPRINT("st%d [%lx]=%lx\n", len, ifa, r2);
if (len != 2 && len != 4 && len != 8) {
DPRINT("unknown size: x6=%d\n", ld.x6_sz);
return -1;
}
/* this assumes little-endian byte-order: */
if (copy_to_user((void __user *) ifa, &r2, len))
return -1;
/*
* stX [r3]=r2,imm(9)
*
* NOTE:
* ld.r3 can never be r0, because r0 would not generate an
* unaligned access.
*/
if (ld.op == 0x5) {
unsigned long imm;
/*
* form imm9: [12:6] contain first 7bits
*/
imm = ld.x << 7 | ld.r1;
/*
* sign extend (8bits) if m set
*/
if (ld.m) imm |= SIGN_EXT9;
/*
* ifa == r3 (NaT is necessarily cleared)
*/
ifa += imm;
DPRINT("imm=%lx r3=%lx\n", imm, ifa);
setreg(ld.r3, ifa, 0, regs);
}
/*
* we don't have alat_invalidate_multiple() so we need
* to do the complete flush :-<<
*/
ia64_invala();
/*
* stX.rel: use fence instead of release
*/
if (ld.x6_op == 0xd)
mb();
return 0;
}
/*
* floating point operations sizes in bytes
*/
static const unsigned char float_fsz[4]={
10, /* extended precision (e) */
8, /* integer (8) */
4, /* single precision (s) */
8 /* double precision (d) */
};
static inline void
mem2float_extended (struct ia64_fpreg *init, struct ia64_fpreg *final)
{
ia64_ldfe(6, init);
ia64_stop();
ia64_stf_spill(final, 6);
}
static inline void
mem2float_integer (struct ia64_fpreg *init, struct ia64_fpreg *final)
{
ia64_ldf8(6, init);
ia64_stop();
ia64_stf_spill(final, 6);
}
static inline void
mem2float_single (struct ia64_fpreg *init, struct ia64_fpreg *final)
{
ia64_ldfs(6, init);
ia64_stop();
ia64_stf_spill(final, 6);
}
static inline void
mem2float_double (struct ia64_fpreg *init, struct ia64_fpreg *final)
{
ia64_ldfd(6, init);
ia64_stop();
ia64_stf_spill(final, 6);
}
static inline void
float2mem_extended (struct ia64_fpreg *init, struct ia64_fpreg *final)
{
ia64_ldf_fill(6, init);
ia64_stop();
ia64_stfe(final, 6);
}
static inline void
float2mem_integer (struct ia64_fpreg *init, struct ia64_fpreg *final)
{
ia64_ldf_fill(6, init);
ia64_stop();
ia64_stf8(final, 6);
}
static inline void
float2mem_single (struct ia64_fpreg *init, struct ia64_fpreg *final)
{
ia64_ldf_fill(6, init);
ia64_stop();
ia64_stfs(final, 6);
}
static inline void
float2mem_double (struct ia64_fpreg *init, struct ia64_fpreg *final)
{
ia64_ldf_fill(6, init);
ia64_stop();
ia64_stfd(final, 6);
}
static int
emulate_load_floatpair (unsigned long ifa, load_store_t ld, struct pt_regs *regs)
{
struct ia64_fpreg fpr_init[2];
struct ia64_fpreg fpr_final[2];
unsigned long len = float_fsz[ld.x6_sz];
/*
* fr0 & fr1 don't need to be checked because Illegal Instruction faults have
* higher priority than unaligned faults.
*
* r0 cannot be found as the base as it would never generate an unaligned
* reference.
*/
/*
* make sure we get clean buffers
*/
memset(&fpr_init, 0, sizeof(fpr_init));
memset(&fpr_final, 0, sizeof(fpr_final));
/*
* ldfpX.a: we don't try to emulate anything but we must
* invalidate the ALAT entry and execute updates, if any.
*/
if (ld.x6_op != 0x2) {
/*
* This assumes little-endian byte-order. Note that there is no "ldfpe"
* instruction:
*/
if (copy_from_user(&fpr_init[0], (void __user *) ifa, len)
|| copy_from_user(&fpr_init[1], (void __user *) (ifa + len), len))
return -1;
DPRINT("ld.r1=%d ld.imm=%d x6_sz=%d\n", ld.r1, ld.imm, ld.x6_sz);
DDUMP("frp_init =", &fpr_init, 2*len);
/*
* XXX fixme
* Could optimize inlines by using ldfpX & 2 spills
*/
switch( ld.x6_sz ) {
case 0:
mem2float_extended(&fpr_init[0], &fpr_final[0]);
mem2float_extended(&fpr_init[1], &fpr_final[1]);
break;
case 1:
mem2float_integer(&fpr_init[0], &fpr_final[0]);
mem2float_integer(&fpr_init[1], &fpr_final[1]);
break;
case 2:
mem2float_single(&fpr_init[0], &fpr_final[0]);
mem2float_single(&fpr_init[1], &fpr_final[1]);
break;
case 3:
mem2float_double(&fpr_init[0], &fpr_final[0]);
mem2float_double(&fpr_init[1], &fpr_final[1]);
break;
}
DDUMP("fpr_final =", &fpr_final, 2*len);
/*
* XXX fixme
*
* A possible optimization would be to drop fpr_final and directly
* use the storage from the saved context i.e., the actual final
* destination (pt_regs, switch_stack or thread structure).
*/
setfpreg(ld.r1, &fpr_final[0], regs);
setfpreg(ld.imm, &fpr_final[1], regs);
}
/*
* Check for updates: only immediate updates are available for this
* instruction.
*/
if (ld.m) {
/*
* the immediate is implicit given the ldsz of the operation:
* single: 8 (2x4) and for all others it's 16 (2x8)
*/
ifa += len<<1;
/*
* IMPORTANT:
* the fact that we force the NaT of r3 to zero is ONLY valid
* as long as we don't come here with a ldfpX.s.
* For this reason we keep this sanity check
*/
if (ld.x6_op == 1 || ld.x6_op == 3)
printk(KERN_ERR "%s: register update on speculative load pair, error\n",
__func__);
setreg(ld.r3, ifa, 0, regs);
}
/*
* Invalidate ALAT entries, if any, for both registers.
*/
if (ld.x6_op == 0x2) {
invala_fr(ld.r1);
invala_fr(ld.imm);
}
return 0;
}
static int
emulate_load_float (unsigned long ifa, load_store_t ld, struct pt_regs *regs)
{
struct ia64_fpreg fpr_init;
struct ia64_fpreg fpr_final;
unsigned long len = float_fsz[ld.x6_sz];
/*
* fr0 & fr1 don't need to be checked because Illegal Instruction
* faults have higher priority than unaligned faults.
*
* r0 cannot be found as the base as it would never generate an
* unaligned reference.
*/
/*
* make sure we get clean buffers
*/
memset(&fpr_init,0, sizeof(fpr_init));
memset(&fpr_final,0, sizeof(fpr_final));
/*
* ldfX.a we don't try to emulate anything but we must
* invalidate the ALAT entry.
* See comments in ldX for descriptions on how the various loads are handled.
*/
if (ld.x6_op != 0x2) {
if (copy_from_user(&fpr_init, (void __user *) ifa, len))
return -1;
DPRINT("ld.r1=%d x6_sz=%d\n", ld.r1, ld.x6_sz);
DDUMP("fpr_init =", &fpr_init, len);
/*
* we only do something for x6_op={0,8,9}
*/
switch( ld.x6_sz ) {
case 0:
mem2float_extended(&fpr_init, &fpr_final);
break;
case 1:
mem2float_integer(&fpr_init, &fpr_final);
break;
case 2:
mem2float_single(&fpr_init, &fpr_final);
break;
case 3:
mem2float_double(&fpr_init, &fpr_final);
break;
}
DDUMP("fpr_final =", &fpr_final, len);
/*
* XXX fixme
*
* A possible optimization would be to drop fpr_final and directly
* use the storage from the saved context i.e., the actual final
* destination (pt_regs, switch_stack or thread structure).
*/
setfpreg(ld.r1, &fpr_final, regs);
}
/*
* check for updates on any loads
*/
if (ld.op == 0x7 || ld.m)
emulate_load_updates(ld.op == 0x7 ? UPD_IMMEDIATE: UPD_REG, ld, regs, ifa);
/*
* invalidate ALAT entry in case of advanced floating point loads
*/
if (ld.x6_op == 0x2)
invala_fr(ld.r1);
return 0;
}
static int
emulate_store_float (unsigned long ifa, load_store_t ld, struct pt_regs *regs)
{
struct ia64_fpreg fpr_init;
struct ia64_fpreg fpr_final;
unsigned long len = float_fsz[ld.x6_sz];
/*
* make sure we get clean buffers
*/
memset(&fpr_init,0, sizeof(fpr_init));
memset(&fpr_final,0, sizeof(fpr_final));
/*
* if we get to this handler, Nat bits on both r3 and r2 have already
* been checked. so we don't need to do it
*
* extract the value to be stored
*/
getfpreg(ld.imm, &fpr_init, regs);
/*
* during this step, we extract the spilled registers from the saved
* context i.e., we refill. Then we store (no spill) to temporary
* aligned location
*/
switch( ld.x6_sz ) {
case 0:
float2mem_extended(&fpr_init, &fpr_final);
break;
case 1:
float2mem_integer(&fpr_init, &fpr_final);
break;
case 2:
float2mem_single(&fpr_init, &fpr_final);
break;
case 3:
float2mem_double(&fpr_init, &fpr_final);
break;
}
DPRINT("ld.r1=%d x6_sz=%d\n", ld.r1, ld.x6_sz);
DDUMP("fpr_init =", &fpr_init, len);
DDUMP("fpr_final =", &fpr_final, len);
if (copy_to_user((void __user *) ifa, &fpr_final, len))
return -1;
/*
* stfX [r3]=r2,imm(9)
*
* NOTE:
* ld.r3 can never be r0, because r0 would not generate an
* unaligned access.
*/
if (ld.op == 0x7) {
unsigned long imm;
/*
* form imm9: [12:6] contain first 7bits
*/
imm = ld.x << 7 | ld.r1;
/*
* sign extend (8bits) if m set
*/
if (ld.m)
imm |= SIGN_EXT9;
/*
* ifa == r3 (NaT is necessarily cleared)
*/
ifa += imm;
DPRINT("imm=%lx r3=%lx\n", imm, ifa);
setreg(ld.r3, ifa, 0, regs);
}
/*
* we don't have alat_invalidate_multiple() so we need
* to do the complete flush :-<<
*/
ia64_invala();
return 0;
}
/*
* Make sure we log the unaligned access, so that user/sysadmin can notice it and
* eventually fix the program. However, we don't want to do that for every access so we
* pace it with jiffies.
*/
static DEFINE_RATELIMIT_STATE(logging_rate_limit, 5 * HZ, 5);
void
ia64_handle_unaligned (unsigned long ifa, struct pt_regs *regs)
{
struct ia64_psr *ipsr = ia64_psr(regs);
mm_segment_t old_fs = get_fs();
unsigned long bundle[2];
unsigned long opcode;
struct siginfo si;
const struct exception_table_entry *eh = NULL;
union {
unsigned long l;
load_store_t insn;
} u;
int ret = -1;
if (ia64_psr(regs)->be) {
/* we don't support big-endian accesses */
if (die_if_kernel("big-endian unaligned accesses are not supported", regs, 0))
return;
goto force_sigbus;
}
/*
* Treat kernel accesses for which there is an exception handler entry the same as
* user-level unaligned accesses. Otherwise, a clever program could trick this
* handler into reading an arbitrary kernel addresses...
*/
if (!user_mode(regs))
eh = search_exception_tables(regs->cr_iip + ia64_psr(regs)->ri);
if (user_mode(regs) || eh) {
if ((current->thread.flags & IA64_THREAD_UAC_SIGBUS) != 0)
goto force_sigbus;
if (!no_unaligned_warning &&
!(current->thread.flags & IA64_THREAD_UAC_NOPRINT) &&
__ratelimit(&logging_rate_limit))
{
char buf[200]; /* comm[] is at most 16 bytes... */
size_t len;
len = sprintf(buf, "%s(%d): unaligned access to 0x%016lx, "
"ip=0x%016lx\n\r", current->comm,
task_pid_nr(current),
ifa, regs->cr_iip + ipsr->ri);
/*
* Don't call tty_write_message() if we're in the kernel; we might
* be holding locks...
*/
if (user_mode(regs))
tty_write_message(current->signal->tty, buf);
buf[len-1] = '\0'; /* drop '\r' */
/* watch for command names containing %s */
printk(KERN_WARNING "%s", buf);
} else {
if (no_unaligned_warning) {
printk_once(KERN_WARNING "%s(%d) encountered an "
"unaligned exception which required\n"
"kernel assistance, which degrades "
"the performance of the application.\n"
"Unaligned exception warnings have "
"been disabled by the system "
"administrator\n"
"echo 0 > /proc/sys/kernel/ignore-"
"unaligned-usertrap to re-enable\n",
current->comm, task_pid_nr(current));
}
}
} else {
if (__ratelimit(&logging_rate_limit)) {
printk(KERN_WARNING "kernel unaligned access to 0x%016lx, ip=0x%016lx\n",
ifa, regs->cr_iip + ipsr->ri);
if (unaligned_dump_stack)
dump_stack();
}
set_fs(KERNEL_DS);
}
DPRINT("iip=%lx ifa=%lx isr=%lx (ei=%d, sp=%d)\n",
regs->cr_iip, ifa, regs->cr_ipsr, ipsr->ri, ipsr->it);
if (__copy_from_user(bundle, (void __user *) regs->cr_iip, 16))
goto failure;
/*
* extract the instruction from the bundle given the slot number
*/
switch (ipsr->ri) {
case 0: u.l = (bundle[0] >> 5); break;
case 1: u.l = (bundle[0] >> 46) | (bundle[1] << 18); break;
case 2: u.l = (bundle[1] >> 23); break;
}
opcode = (u.l >> IA64_OPCODE_SHIFT) & IA64_OPCODE_MASK;
DPRINT("opcode=%lx ld.qp=%d ld.r1=%d ld.imm=%d ld.r3=%d ld.x=%d ld.hint=%d "
"ld.x6=0x%x ld.m=%d ld.op=%d\n", opcode, u.insn.qp, u.insn.r1, u.insn.imm,
u.insn.r3, u.insn.x, u.insn.hint, u.insn.x6_sz, u.insn.m, u.insn.op);
/*
* IMPORTANT:
* Notice that the switch statement DOES not cover all possible instructions
* that DO generate unaligned references. This is made on purpose because for some
* instructions it DOES NOT make sense to try and emulate the access. Sometimes it
* is WRONG to try and emulate. Here is a list of instruction we don't emulate i.e.,
* the program will get a signal and die:
*
* load/store:
* - ldX.spill
* - stX.spill
* Reason: RNATs are based on addresses
* - ld16
* - st16
* Reason: ld16 and st16 are supposed to occur in a single
* memory op
*
* synchronization:
* - cmpxchg
* - fetchadd
* - xchg
* Reason: ATOMIC operations cannot be emulated properly using multiple
* instructions.
*
* speculative loads:
* - ldX.sZ
* Reason: side effects, code must be ready to deal with failure so simpler
* to let the load fail.
* ---------------------------------------------------------------------------------
* XXX fixme
*
* I would like to get rid of this switch case and do something
* more elegant.
*/
switch (opcode) {
case LDS_OP:
case LDSA_OP:
if (u.insn.x)
/* oops, really a semaphore op (cmpxchg, etc) */
goto failure;
/* no break */
case LDS_IMM_OP:
case LDSA_IMM_OP:
case LDFS_OP:
case LDFSA_OP:
case LDFS_IMM_OP:
/*
* The instruction will be retried with deferred exceptions turned on, and
* we should get Nat bit installed
*
* IMPORTANT: When PSR_ED is set, the register & immediate update forms
* are actually executed even though the operation failed. So we don't
* need to take care of this.
*/
DPRINT("forcing PSR_ED\n");
regs->cr_ipsr |= IA64_PSR_ED;
goto done;
case LD_OP:
case LDA_OP:
case LDBIAS_OP:
case LDACQ_OP:
case LDCCLR_OP:
case LDCNC_OP:
case LDCCLRACQ_OP:
if (u.insn.x)
/* oops, really a semaphore op (cmpxchg, etc) */
goto failure;
/* no break */
case LD_IMM_OP:
case LDA_IMM_OP:
case LDBIAS_IMM_OP:
case LDACQ_IMM_OP:
case LDCCLR_IMM_OP:
case LDCNC_IMM_OP:
case LDCCLRACQ_IMM_OP:
ret = emulate_load_int(ifa, u.insn, regs);
break;
case ST_OP:
case STREL_OP:
if (u.insn.x)
/* oops, really a semaphore op (cmpxchg, etc) */
goto failure;
/* no break */
case ST_IMM_OP:
case STREL_IMM_OP:
ret = emulate_store_int(ifa, u.insn, regs);
break;
case LDF_OP:
case LDFA_OP:
case LDFCCLR_OP:
case LDFCNC_OP:
if (u.insn.x)
ret = emulate_load_floatpair(ifa, u.insn, regs);
else
ret = emulate_load_float(ifa, u.insn, regs);
break;
case LDF_IMM_OP:
case LDFA_IMM_OP:
case LDFCCLR_IMM_OP:
case LDFCNC_IMM_OP:
ret = emulate_load_float(ifa, u.insn, regs);
break;
case STF_OP:
case STF_IMM_OP:
ret = emulate_store_float(ifa, u.insn, regs);
break;
default:
goto failure;
}
DPRINT("ret=%d\n", ret);
if (ret)
goto failure;
if (ipsr->ri == 2)
/*
* given today's architecture this case is not likely to happen because a
* memory access instruction (M) can never be in the last slot of a
* bundle. But let's keep it for now.
*/
regs->cr_iip += 16;
ipsr->ri = (ipsr->ri + 1) & 0x3;
DPRINT("ipsr->ri=%d iip=%lx\n", ipsr->ri, regs->cr_iip);
done:
set_fs(old_fs); /* restore original address limit */
return;
failure:
/* something went wrong... */
if (!user_mode(regs)) {
if (eh) {
ia64_handle_exception(regs, eh);
goto done;
}
if (die_if_kernel("error during unaligned kernel access\n", regs, ret))
return;
/* NOT_REACHED */
}
force_sigbus:
si.si_signo = SIGBUS;
si.si_errno = 0;
si.si_code = BUS_ADRALN;
si.si_addr = (void __user *) ifa;
si.si_flags = 0;
si.si_isr = 0;
si.si_imm = 0;
force_sig_info(SIGBUS, &si, current);
goto done;
}