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linux/arch/powerpc/lib/sstep.c
Oliver O'Halloran 6670783606 powerpc/sstep: Fix emulation fall-through 
There is a switch fallthough in instr_analyze() which can cause an
invalid instruction to be emulated as a different, valid, instruction.
The rld* (opcode 30) case extracts a sub-opcode from bits 3:1 of the
instruction word. However, the only valid values of this field are 001
and 000. These cases are correctly handled, but the others are not which
causes execution to fall through into case 31.

Breaking out of the switch causes the instruction to be marked as
unknown and allows the caller to deal with the invalid instruction in a
manner consistent with other invalid instructions.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-05-11 21:54:08 +10:00

2021 lines
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/*
* Single-step support.
*
* Copyright (C) 2004 Paul Mackerras <paulus@au.ibm.com>, IBM
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/kernel.h>
#include <linux/kprobes.h>
#include <linux/ptrace.h>
#include <linux/prefetch.h>
#include <asm/sstep.h>
#include <asm/processor.h>
#include <asm/uaccess.h>
#include <asm/cputable.h>
extern char system_call_common[];
#ifdef CONFIG_PPC64
/* Bits in SRR1 that are copied from MSR */
#define MSR_MASK 0xffffffff87c0ffffUL
#else
#define MSR_MASK 0x87c0ffff
#endif
/* Bits in XER */
#define XER_SO 0x80000000U
#define XER_OV 0x40000000U
#define XER_CA 0x20000000U
#ifdef CONFIG_PPC_FPU
/*
* Functions in ldstfp.S
*/
extern int do_lfs(int rn, unsigned long ea);
extern int do_lfd(int rn, unsigned long ea);
extern int do_stfs(int rn, unsigned long ea);
extern int do_stfd(int rn, unsigned long ea);
extern int do_lvx(int rn, unsigned long ea);
extern int do_stvx(int rn, unsigned long ea);
extern int do_lxvd2x(int rn, unsigned long ea);
extern int do_stxvd2x(int rn, unsigned long ea);
#endif
/*
* Emulate the truncation of 64 bit values in 32-bit mode.
*/
static unsigned long truncate_if_32bit(unsigned long msr, unsigned long val)
{
#ifdef __powerpc64__
if ((msr & MSR_64BIT) == 0)
val &= 0xffffffffUL;
#endif
return val;
}
/*
* Determine whether a conditional branch instruction would branch.
*/
static int __kprobes branch_taken(unsigned int instr, struct pt_regs *regs)
{
unsigned int bo = (instr >> 21) & 0x1f;
unsigned int bi;
if ((bo & 4) == 0) {
/* decrement counter */
--regs->ctr;
if (((bo >> 1) & 1) ^ (regs->ctr == 0))
return 0;
}
if ((bo & 0x10) == 0) {
/* check bit from CR */
bi = (instr >> 16) & 0x1f;
if (((regs->ccr >> (31 - bi)) & 1) != ((bo >> 3) & 1))
return 0;
}
return 1;
}
static long __kprobes address_ok(struct pt_regs *regs, unsigned long ea, int nb)
{
if (!user_mode(regs))
return 1;
return __access_ok(ea, nb, USER_DS);
}
/*
* Calculate effective address for a D-form instruction
*/
static unsigned long __kprobes dform_ea(unsigned int instr, struct pt_regs *regs)
{
int ra;
unsigned long ea;
ra = (instr >> 16) & 0x1f;
ea = (signed short) instr; /* sign-extend */
if (ra)
ea += regs->gpr[ra];
return truncate_if_32bit(regs->msr, ea);
}
#ifdef __powerpc64__
/*
* Calculate effective address for a DS-form instruction
*/
static unsigned long __kprobes dsform_ea(unsigned int instr, struct pt_regs *regs)
{
int ra;
unsigned long ea;
ra = (instr >> 16) & 0x1f;
ea = (signed short) (instr & ~3); /* sign-extend */
if (ra)
ea += regs->gpr[ra];
return truncate_if_32bit(regs->msr, ea);
}
#endif /* __powerpc64 */
/*
* Calculate effective address for an X-form instruction
*/
static unsigned long __kprobes xform_ea(unsigned int instr,
struct pt_regs *regs)
{
int ra, rb;
unsigned long ea;
ra = (instr >> 16) & 0x1f;
rb = (instr >> 11) & 0x1f;
ea = regs->gpr[rb];
if (ra)
ea += regs->gpr[ra];
return truncate_if_32bit(regs->msr, ea);
}
/*
* Return the largest power of 2, not greater than sizeof(unsigned long),
* such that x is a multiple of it.
*/
static inline unsigned long max_align(unsigned long x)
{
x |= sizeof(unsigned long);
return x & -x; /* isolates rightmost bit */
}
static inline unsigned long byterev_2(unsigned long x)
{
return ((x >> 8) & 0xff) | ((x & 0xff) << 8);
}
static inline unsigned long byterev_4(unsigned long x)
{
return ((x >> 24) & 0xff) | ((x >> 8) & 0xff00) |
((x & 0xff00) << 8) | ((x & 0xff) << 24);
}
#ifdef __powerpc64__
static inline unsigned long byterev_8(unsigned long x)
{
return (byterev_4(x) << 32) | byterev_4(x >> 32);
}
#endif
static int __kprobes read_mem_aligned(unsigned long *dest, unsigned long ea,
int nb)
{
int err = 0;
unsigned long x = 0;
switch (nb) {
case 1:
err = __get_user(x, (unsigned char __user *) ea);
break;
case 2:
err = __get_user(x, (unsigned short __user *) ea);
break;
case 4:
err = __get_user(x, (unsigned int __user *) ea);
break;
#ifdef __powerpc64__
case 8:
err = __get_user(x, (unsigned long __user *) ea);
break;
#endif
}
if (!err)
*dest = x;
return err;
}
static int __kprobes read_mem_unaligned(unsigned long *dest, unsigned long ea,
int nb, struct pt_regs *regs)
{
int err;
unsigned long x, b, c;
#ifdef __LITTLE_ENDIAN__
int len = nb; /* save a copy of the length for byte reversal */
#endif
/* unaligned, do this in pieces */
x = 0;
for (; nb > 0; nb -= c) {
#ifdef __LITTLE_ENDIAN__
c = 1;
#endif
#ifdef __BIG_ENDIAN__
c = max_align(ea);
#endif
if (c > nb)
c = max_align(nb);
err = read_mem_aligned(&b, ea, c);
if (err)
return err;
x = (x << (8 * c)) + b;
ea += c;
}
#ifdef __LITTLE_ENDIAN__
switch (len) {
case 2:
*dest = byterev_2(x);
break;
case 4:
*dest = byterev_4(x);
break;
#ifdef __powerpc64__
case 8:
*dest = byterev_8(x);
break;
#endif
}
#endif
#ifdef __BIG_ENDIAN__
*dest = x;
#endif
return 0;
}
/*
* Read memory at address ea for nb bytes, return 0 for success
* or -EFAULT if an error occurred.
*/
static int __kprobes read_mem(unsigned long *dest, unsigned long ea, int nb,
struct pt_regs *regs)
{
if (!address_ok(regs, ea, nb))
return -EFAULT;
if ((ea & (nb - 1)) == 0)
return read_mem_aligned(dest, ea, nb);
return read_mem_unaligned(dest, ea, nb, regs);
}
static int __kprobes write_mem_aligned(unsigned long val, unsigned long ea,
int nb)
{
int err = 0;
switch (nb) {
case 1:
err = __put_user(val, (unsigned char __user *) ea);
break;
case 2:
err = __put_user(val, (unsigned short __user *) ea);
break;
case 4:
err = __put_user(val, (unsigned int __user *) ea);
break;
#ifdef __powerpc64__
case 8:
err = __put_user(val, (unsigned long __user *) ea);
break;
#endif
}
return err;
}
static int __kprobes write_mem_unaligned(unsigned long val, unsigned long ea,
int nb, struct pt_regs *regs)
{
int err;
unsigned long c;
#ifdef __LITTLE_ENDIAN__
switch (nb) {
case 2:
val = byterev_2(val);
break;
case 4:
val = byterev_4(val);
break;
#ifdef __powerpc64__
case 8:
val = byterev_8(val);
break;
#endif
}
#endif
/* unaligned or little-endian, do this in pieces */
for (; nb > 0; nb -= c) {
#ifdef __LITTLE_ENDIAN__
c = 1;
#endif
#ifdef __BIG_ENDIAN__
c = max_align(ea);
#endif
if (c > nb)
c = max_align(nb);
err = write_mem_aligned(val >> (nb - c) * 8, ea, c);
if (err)
return err;
ea += c;
}
return 0;
}
/*
* Write memory at address ea for nb bytes, return 0 for success
* or -EFAULT if an error occurred.
*/
static int __kprobes write_mem(unsigned long val, unsigned long ea, int nb,
struct pt_regs *regs)
{
if (!address_ok(regs, ea, nb))
return -EFAULT;
if ((ea & (nb - 1)) == 0)
return write_mem_aligned(val, ea, nb);
return write_mem_unaligned(val, ea, nb, regs);
}
#ifdef CONFIG_PPC_FPU
/*
* Check the address and alignment, and call func to do the actual
* load or store.
*/
static int __kprobes do_fp_load(int rn, int (*func)(int, unsigned long),
unsigned long ea, int nb,
struct pt_regs *regs)
{
int err;
union {
double dbl;
unsigned long ul[2];
struct {
#ifdef __BIG_ENDIAN__
unsigned _pad_;
unsigned word;
#endif
#ifdef __LITTLE_ENDIAN__
unsigned word;
unsigned _pad_;
#endif
} single;
} data;
unsigned long ptr;
if (!address_ok(regs, ea, nb))
return -EFAULT;
if ((ea & 3) == 0)
return (*func)(rn, ea);
ptr = (unsigned long) &data.ul;
if (sizeof(unsigned long) == 8 || nb == 4) {
err = read_mem_unaligned(&data.ul[0], ea, nb, regs);
if (nb == 4)
ptr = (unsigned long)&(data.single.word);
} else {
/* reading a double on 32-bit */
err = read_mem_unaligned(&data.ul[0], ea, 4, regs);
if (!err)
err = read_mem_unaligned(&data.ul[1], ea + 4, 4, regs);
}
if (err)
return err;
return (*func)(rn, ptr);
}
static int __kprobes do_fp_store(int rn, int (*func)(int, unsigned long),
unsigned long ea, int nb,
struct pt_regs *regs)
{
int err;
union {
double dbl;
unsigned long ul[2];
struct {
#ifdef __BIG_ENDIAN__
unsigned _pad_;
unsigned word;
#endif
#ifdef __LITTLE_ENDIAN__
unsigned word;
unsigned _pad_;
#endif
} single;
} data;
unsigned long ptr;
if (!address_ok(regs, ea, nb))
return -EFAULT;
if ((ea & 3) == 0)
return (*func)(rn, ea);
ptr = (unsigned long) &data.ul[0];
if (sizeof(unsigned long) == 8 || nb == 4) {
if (nb == 4)
ptr = (unsigned long)&(data.single.word);
err = (*func)(rn, ptr);
if (err)
return err;
err = write_mem_unaligned(data.ul[0], ea, nb, regs);
} else {
/* writing a double on 32-bit */
err = (*func)(rn, ptr);
if (err)
return err;
err = write_mem_unaligned(data.ul[0], ea, 4, regs);
if (!err)
err = write_mem_unaligned(data.ul[1], ea + 4, 4, regs);
}
return err;
}
#endif
#ifdef CONFIG_ALTIVEC
/* For Altivec/VMX, no need to worry about alignment */
static int __kprobes do_vec_load(int rn, int (*func)(int, unsigned long),
unsigned long ea, struct pt_regs *regs)
{
if (!address_ok(regs, ea & ~0xfUL, 16))
return -EFAULT;
return (*func)(rn, ea);
}
static int __kprobes do_vec_store(int rn, int (*func)(int, unsigned long),
unsigned long ea, struct pt_regs *regs)
{
if (!address_ok(regs, ea & ~0xfUL, 16))
return -EFAULT;
return (*func)(rn, ea);
}
#endif /* CONFIG_ALTIVEC */
#ifdef CONFIG_VSX
static int __kprobes do_vsx_load(int rn, int (*func)(int, unsigned long),
unsigned long ea, struct pt_regs *regs)
{
int err;
unsigned long val[2];
if (!address_ok(regs, ea, 16))
return -EFAULT;
if ((ea & 3) == 0)
return (*func)(rn, ea);
err = read_mem_unaligned(&val[0], ea, 8, regs);
if (!err)
err = read_mem_unaligned(&val[1], ea + 8, 8, regs);
if (!err)
err = (*func)(rn, (unsigned long) &val[0]);
return err;
}
static int __kprobes do_vsx_store(int rn, int (*func)(int, unsigned long),
unsigned long ea, struct pt_regs *regs)
{
int err;
unsigned long val[2];
if (!address_ok(regs, ea, 16))
return -EFAULT;
if ((ea & 3) == 0)
return (*func)(rn, ea);
err = (*func)(rn, (unsigned long) &val[0]);
if (err)
return err;
err = write_mem_unaligned(val[0], ea, 8, regs);
if (!err)
err = write_mem_unaligned(val[1], ea + 8, 8, regs);
return err;
}
#endif /* CONFIG_VSX */
#define __put_user_asmx(x, addr, err, op, cr) \
__asm__ __volatile__( \
"1: " op " %2,0,%3\n" \
" mfcr %1\n" \
"2:\n" \
".section .fixup,\"ax\"\n" \
"3: li %0,%4\n" \
" b 2b\n" \
".previous\n" \
".section __ex_table,\"a\"\n" \
PPC_LONG_ALIGN "\n" \
PPC_LONG "1b,3b\n" \
".previous" \
: "=r" (err), "=r" (cr) \
: "r" (x), "r" (addr), "i" (-EFAULT), "0" (err))
#define __get_user_asmx(x, addr, err, op) \
__asm__ __volatile__( \
"1: "op" %1,0,%2\n" \
"2:\n" \
".section .fixup,\"ax\"\n" \
"3: li %0,%3\n" \
" b 2b\n" \
".previous\n" \
".section __ex_table,\"a\"\n" \
PPC_LONG_ALIGN "\n" \
PPC_LONG "1b,3b\n" \
".previous" \
: "=r" (err), "=r" (x) \
: "r" (addr), "i" (-EFAULT), "0" (err))
#define __cacheop_user_asmx(addr, err, op) \
__asm__ __volatile__( \
"1: "op" 0,%1\n" \
"2:\n" \
".section .fixup,\"ax\"\n" \
"3: li %0,%3\n" \
" b 2b\n" \
".previous\n" \
".section __ex_table,\"a\"\n" \
PPC_LONG_ALIGN "\n" \
PPC_LONG "1b,3b\n" \
".previous" \
: "=r" (err) \
: "r" (addr), "i" (-EFAULT), "0" (err))
static void __kprobes set_cr0(struct pt_regs *regs, int rd)
{
long val = regs->gpr[rd];
regs->ccr = (regs->ccr & 0x0fffffff) | ((regs->xer >> 3) & 0x10000000);
#ifdef __powerpc64__
if (!(regs->msr & MSR_64BIT))
val = (int) val;
#endif
if (val < 0)
regs->ccr |= 0x80000000;
else if (val > 0)
regs->ccr |= 0x40000000;
else
regs->ccr |= 0x20000000;
}
static void __kprobes add_with_carry(struct pt_regs *regs, int rd,
unsigned long val1, unsigned long val2,
unsigned long carry_in)
{
unsigned long val = val1 + val2;
if (carry_in)
++val;
regs->gpr[rd] = val;
#ifdef __powerpc64__
if (!(regs->msr & MSR_64BIT)) {
val = (unsigned int) val;
val1 = (unsigned int) val1;
}
#endif
if (val < val1 || (carry_in && val == val1))
regs->xer |= XER_CA;
else
regs->xer &= ~XER_CA;
}
static void __kprobes do_cmp_signed(struct pt_regs *regs, long v1, long v2,
int crfld)
{
unsigned int crval, shift;
crval = (regs->xer >> 31) & 1; /* get SO bit */
if (v1 < v2)
crval |= 8;
else if (v1 > v2)
crval |= 4;
else
crval |= 2;
shift = (7 - crfld) * 4;
regs->ccr = (regs->ccr & ~(0xf << shift)) | (crval << shift);
}
static void __kprobes do_cmp_unsigned(struct pt_regs *regs, unsigned long v1,
unsigned long v2, int crfld)
{
unsigned int crval, shift;
crval = (regs->xer >> 31) & 1; /* get SO bit */
if (v1 < v2)
crval |= 8;
else if (v1 > v2)
crval |= 4;
else
crval |= 2;
shift = (7 - crfld) * 4;
regs->ccr = (regs->ccr & ~(0xf << shift)) | (crval << shift);
}
static int __kprobes trap_compare(long v1, long v2)
{
int ret = 0;
if (v1 < v2)
ret |= 0x10;
else if (v1 > v2)
ret |= 0x08;
else
ret |= 0x04;
if ((unsigned long)v1 < (unsigned long)v2)
ret |= 0x02;
else if ((unsigned long)v1 > (unsigned long)v2)
ret |= 0x01;
return ret;
}
/*
* Elements of 32-bit rotate and mask instructions.
*/
#define MASK32(mb, me) ((0xffffffffUL >> (mb)) + \
((signed long)-0x80000000L >> (me)) + ((me) >= (mb)))
#ifdef __powerpc64__
#define MASK64_L(mb) (~0UL >> (mb))
#define MASK64_R(me) ((signed long)-0x8000000000000000L >> (me))
#define MASK64(mb, me) (MASK64_L(mb) + MASK64_R(me) + ((me) >= (mb)))
#define DATA32(x) (((x) & 0xffffffffUL) | (((x) & 0xffffffffUL) << 32))
#else
#define DATA32(x) (x)
#endif
#define ROTATE(x, n) ((n) ? (((x) << (n)) | ((x) >> (8 * sizeof(long) - (n)))) : (x))
/*
* Decode an instruction, and execute it if that can be done just by
* modifying *regs (i.e. integer arithmetic and logical instructions,
* branches, and barrier instructions).
* Returns 1 if the instruction has been executed, or 0 if not.
* Sets *op to indicate what the instruction does.
*/
int __kprobes analyse_instr(struct instruction_op *op, struct pt_regs *regs,
unsigned int instr)
{
unsigned int opcode, ra, rb, rd, spr, u;
unsigned long int imm;
unsigned long int val, val2;
unsigned int mb, me, sh;
long ival;
op->type = COMPUTE;
opcode = instr >> 26;
switch (opcode) {
case 16: /* bc */
op->type = BRANCH;
imm = (signed short)(instr & 0xfffc);
if ((instr & 2) == 0)
imm += regs->nip;
regs->nip += 4;
regs->nip = truncate_if_32bit(regs->msr, regs->nip);
if (instr & 1)
regs->link = regs->nip;
if (branch_taken(instr, regs))
regs->nip = truncate_if_32bit(regs->msr, imm);
return 1;
#ifdef CONFIG_PPC64
case 17: /* sc */
if ((instr & 0xfe2) == 2)
op->type = SYSCALL;
else
op->type = UNKNOWN;
return 0;
#endif
case 18: /* b */
op->type = BRANCH;
imm = instr & 0x03fffffc;
if (imm & 0x02000000)
imm -= 0x04000000;
if ((instr & 2) == 0)
imm += regs->nip;
if (instr & 1)
regs->link = truncate_if_32bit(regs->msr, regs->nip + 4);
imm = truncate_if_32bit(regs->msr, imm);
regs->nip = imm;
return 1;
case 19:
switch ((instr >> 1) & 0x3ff) {
case 0: /* mcrf */
rd = (instr >> 21) & 0x1c;
ra = (instr >> 16) & 0x1c;
val = (regs->ccr >> ra) & 0xf;
regs->ccr = (regs->ccr & ~(0xfUL << rd)) | (val << rd);
goto instr_done;
case 16: /* bclr */
case 528: /* bcctr */
op->type = BRANCH;
imm = (instr & 0x400)? regs->ctr: regs->link;
regs->nip = truncate_if_32bit(regs->msr, regs->nip + 4);
imm = truncate_if_32bit(regs->msr, imm);
if (instr & 1)
regs->link = regs->nip;
if (branch_taken(instr, regs))
regs->nip = imm;
return 1;
case 18: /* rfid, scary */
if (regs->msr & MSR_PR)
goto priv;
op->type = RFI;
return 0;
case 150: /* isync */
op->type = BARRIER;
isync();
goto instr_done;
case 33: /* crnor */
case 129: /* crandc */
case 193: /* crxor */
case 225: /* crnand */
case 257: /* crand */
case 289: /* creqv */
case 417: /* crorc */
case 449: /* cror */
ra = (instr >> 16) & 0x1f;
rb = (instr >> 11) & 0x1f;
rd = (instr >> 21) & 0x1f;
ra = (regs->ccr >> (31 - ra)) & 1;
rb = (regs->ccr >> (31 - rb)) & 1;
val = (instr >> (6 + ra * 2 + rb)) & 1;
regs->ccr = (regs->ccr & ~(1UL << (31 - rd))) |
(val << (31 - rd));
goto instr_done;
}
break;
case 31:
switch ((instr >> 1) & 0x3ff) {
case 598: /* sync */
op->type = BARRIER;
#ifdef __powerpc64__
switch ((instr >> 21) & 3) {
case 1: /* lwsync */
asm volatile("lwsync" : : : "memory");
goto instr_done;
case 2: /* ptesync */
asm volatile("ptesync" : : : "memory");
goto instr_done;
}
#endif
mb();
goto instr_done;
case 854: /* eieio */
op->type = BARRIER;
eieio();
goto instr_done;
}
break;
}
/* Following cases refer to regs->gpr[], so we need all regs */
if (!FULL_REGS(regs))
return 0;
rd = (instr >> 21) & 0x1f;
ra = (instr >> 16) & 0x1f;
rb = (instr >> 11) & 0x1f;
switch (opcode) {
#ifdef __powerpc64__
case 2: /* tdi */
if (rd & trap_compare(regs->gpr[ra], (short) instr))
goto trap;
goto instr_done;
#endif
case 3: /* twi */
if (rd & trap_compare((int)regs->gpr[ra], (short) instr))
goto trap;
goto instr_done;
case 7: /* mulli */
regs->gpr[rd] = regs->gpr[ra] * (short) instr;
goto instr_done;
case 8: /* subfic */
imm = (short) instr;
add_with_carry(regs, rd, ~regs->gpr[ra], imm, 1);
goto instr_done;
case 10: /* cmpli */
imm = (unsigned short) instr;
val = regs->gpr[ra];
#ifdef __powerpc64__
if ((rd & 1) == 0)
val = (unsigned int) val;
#endif
do_cmp_unsigned(regs, val, imm, rd >> 2);
goto instr_done;
case 11: /* cmpi */
imm = (short) instr;
val = regs->gpr[ra];
#ifdef __powerpc64__
if ((rd & 1) == 0)
val = (int) val;
#endif
do_cmp_signed(regs, val, imm, rd >> 2);
goto instr_done;
case 12: /* addic */
imm = (short) instr;
add_with_carry(regs, rd, regs->gpr[ra], imm, 0);
goto instr_done;
case 13: /* addic. */
imm = (short) instr;
add_with_carry(regs, rd, regs->gpr[ra], imm, 0);
set_cr0(regs, rd);
goto instr_done;
case 14: /* addi */
imm = (short) instr;
if (ra)
imm += regs->gpr[ra];
regs->gpr[rd] = imm;
goto instr_done;
case 15: /* addis */
imm = ((short) instr) << 16;
if (ra)
imm += regs->gpr[ra];
regs->gpr[rd] = imm;
goto instr_done;
case 20: /* rlwimi */
mb = (instr >> 6) & 0x1f;
me = (instr >> 1) & 0x1f;
val = DATA32(regs->gpr[rd]);
imm = MASK32(mb, me);
regs->gpr[ra] = (regs->gpr[ra] & ~imm) | (ROTATE(val, rb) & imm);
goto logical_done;
case 21: /* rlwinm */
mb = (instr >> 6) & 0x1f;
me = (instr >> 1) & 0x1f;
val = DATA32(regs->gpr[rd]);
regs->gpr[ra] = ROTATE(val, rb) & MASK32(mb, me);
goto logical_done;
case 23: /* rlwnm */
mb = (instr >> 6) & 0x1f;
me = (instr >> 1) & 0x1f;
rb = regs->gpr[rb] & 0x1f;
val = DATA32(regs->gpr[rd]);
regs->gpr[ra] = ROTATE(val, rb) & MASK32(mb, me);
goto logical_done;
case 24: /* ori */
imm = (unsigned short) instr;
regs->gpr[ra] = regs->gpr[rd] | imm;
goto instr_done;
case 25: /* oris */
imm = (unsigned short) instr;
regs->gpr[ra] = regs->gpr[rd] | (imm << 16);
goto instr_done;
case 26: /* xori */
imm = (unsigned short) instr;
regs->gpr[ra] = regs->gpr[rd] ^ imm;
goto instr_done;
case 27: /* xoris */
imm = (unsigned short) instr;
regs->gpr[ra] = regs->gpr[rd] ^ (imm << 16);
goto instr_done;
case 28: /* andi. */
imm = (unsigned short) instr;
regs->gpr[ra] = regs->gpr[rd] & imm;
set_cr0(regs, ra);
goto instr_done;
case 29: /* andis. */
imm = (unsigned short) instr;
regs->gpr[ra] = regs->gpr[rd] & (imm << 16);
set_cr0(regs, ra);
goto instr_done;
#ifdef __powerpc64__
case 30: /* rld* */
mb = ((instr >> 6) & 0x1f) | (instr & 0x20);
val = regs->gpr[rd];
if ((instr & 0x10) == 0) {
sh = rb | ((instr & 2) << 4);
val = ROTATE(val, sh);
switch ((instr >> 2) & 3) {
case 0: /* rldicl */
regs->gpr[ra] = val & MASK64_L(mb);
goto logical_done;
case 1: /* rldicr */
regs->gpr[ra] = val & MASK64_R(mb);
goto logical_done;
case 2: /* rldic */
regs->gpr[ra] = val & MASK64(mb, 63 - sh);
goto logical_done;
case 3: /* rldimi */
imm = MASK64(mb, 63 - sh);
regs->gpr[ra] = (regs->gpr[ra] & ~imm) |
(val & imm);
goto logical_done;
}
} else {
sh = regs->gpr[rb] & 0x3f;
val = ROTATE(val, sh);
switch ((instr >> 1) & 7) {
case 0: /* rldcl */
regs->gpr[ra] = val & MASK64_L(mb);
goto logical_done;
case 1: /* rldcr */
regs->gpr[ra] = val & MASK64_R(mb);
goto logical_done;
}
}
#endif
break; /* illegal instruction */
case 31:
switch ((instr >> 1) & 0x3ff) {
case 4: /* tw */
if (rd == 0x1f ||
(rd & trap_compare((int)regs->gpr[ra],
(int)regs->gpr[rb])))
goto trap;
goto instr_done;
#ifdef __powerpc64__
case 68: /* td */
if (rd & trap_compare(regs->gpr[ra], regs->gpr[rb]))
goto trap;
goto instr_done;
#endif
case 83: /* mfmsr */
if (regs->msr & MSR_PR)
goto priv;
op->type = MFMSR;
op->reg = rd;
return 0;
case 146: /* mtmsr */
if (regs->msr & MSR_PR)
goto priv;
op->type = MTMSR;
op->reg = rd;
op->val = 0xffffffff & ~(MSR_ME | MSR_LE);
return 0;
#ifdef CONFIG_PPC64
case 178: /* mtmsrd */
if (regs->msr & MSR_PR)
goto priv;
op->type = MTMSR;
op->reg = rd;
/* only MSR_EE and MSR_RI get changed if bit 15 set */
/* mtmsrd doesn't change MSR_HV, MSR_ME or MSR_LE */
imm = (instr & 0x10000)? 0x8002: 0xefffffffffffeffeUL;
op->val = imm;
return 0;
#endif
case 19: /* mfcr */
regs->gpr[rd] = regs->ccr;
regs->gpr[rd] &= 0xffffffffUL;
goto instr_done;
case 144: /* mtcrf */
imm = 0xf0000000UL;
val = regs->gpr[rd];
for (sh = 0; sh < 8; ++sh) {
if (instr & (0x80000 >> sh))
regs->ccr = (regs->ccr & ~imm) |
(val & imm);
imm >>= 4;
}
goto instr_done;
case 339: /* mfspr */
spr = ((instr >> 16) & 0x1f) | ((instr >> 6) & 0x3e0);
switch (spr) {
case SPRN_XER: /* mfxer */
regs->gpr[rd] = regs->xer;
regs->gpr[rd] &= 0xffffffffUL;
goto instr_done;
case SPRN_LR: /* mflr */
regs->gpr[rd] = regs->link;
goto instr_done;
case SPRN_CTR: /* mfctr */
regs->gpr[rd] = regs->ctr;
goto instr_done;
default:
op->type = MFSPR;
op->reg = rd;
op->spr = spr;
return 0;
}
break;
case 467: /* mtspr */
spr = ((instr >> 16) & 0x1f) | ((instr >> 6) & 0x3e0);
switch (spr) {
case SPRN_XER: /* mtxer */
regs->xer = (regs->gpr[rd] & 0xffffffffUL);
goto instr_done;
case SPRN_LR: /* mtlr */
regs->link = regs->gpr[rd];
goto instr_done;
case SPRN_CTR: /* mtctr */
regs->ctr = regs->gpr[rd];
goto instr_done;
default:
op->type = MTSPR;
op->val = regs->gpr[rd];
op->spr = spr;
return 0;
}
break;
/*
* Compare instructions
*/
case 0: /* cmp */
val = regs->gpr[ra];
val2 = regs->gpr[rb];
#ifdef __powerpc64__
if ((rd & 1) == 0) {
/* word (32-bit) compare */
val = (int) val;
val2 = (int) val2;
}
#endif
do_cmp_signed(regs, val, val2, rd >> 2);
goto instr_done;
case 32: /* cmpl */
val = regs->gpr[ra];
val2 = regs->gpr[rb];
#ifdef __powerpc64__
if ((rd & 1) == 0) {
/* word (32-bit) compare */
val = (unsigned int) val;
val2 = (unsigned int) val2;
}
#endif
do_cmp_unsigned(regs, val, val2, rd >> 2);
goto instr_done;
/*
* Arithmetic instructions
*/
case 8: /* subfc */
add_with_carry(regs, rd, ~regs->gpr[ra],
regs->gpr[rb], 1);
goto arith_done;
#ifdef __powerpc64__
case 9: /* mulhdu */
asm("mulhdu %0,%1,%2" : "=r" (regs->gpr[rd]) :
"r" (regs->gpr[ra]), "r" (regs->gpr[rb]));
goto arith_done;
#endif
case 10: /* addc */
add_with_carry(regs, rd, regs->gpr[ra],
regs->gpr[rb], 0);
goto arith_done;
case 11: /* mulhwu */
asm("mulhwu %0,%1,%2" : "=r" (regs->gpr[rd]) :
"r" (regs->gpr[ra]), "r" (regs->gpr[rb]));
goto arith_done;
case 40: /* subf */
regs->gpr[rd] = regs->gpr[rb] - regs->gpr[ra];
goto arith_done;
#ifdef __powerpc64__
case 73: /* mulhd */
asm("mulhd %0,%1,%2" : "=r" (regs->gpr[rd]) :
"r" (regs->gpr[ra]), "r" (regs->gpr[rb]));
goto arith_done;
#endif
case 75: /* mulhw */
asm("mulhw %0,%1,%2" : "=r" (regs->gpr[rd]) :
"r" (regs->gpr[ra]), "r" (regs->gpr[rb]));
goto arith_done;
case 104: /* neg */
regs->gpr[rd] = -regs->gpr[ra];
goto arith_done;
case 136: /* subfe */
add_with_carry(regs, rd, ~regs->gpr[ra], regs->gpr[rb],
regs->xer & XER_CA);
goto arith_done;
case 138: /* adde */
add_with_carry(regs, rd, regs->gpr[ra], regs->gpr[rb],
regs->xer & XER_CA);
goto arith_done;
case 200: /* subfze */
add_with_carry(regs, rd, ~regs->gpr[ra], 0L,
regs->xer & XER_CA);
goto arith_done;
case 202: /* addze */
add_with_carry(regs, rd, regs->gpr[ra], 0L,
regs->xer & XER_CA);
goto arith_done;
case 232: /* subfme */
add_with_carry(regs, rd, ~regs->gpr[ra], -1L,
regs->xer & XER_CA);
goto arith_done;
#ifdef __powerpc64__
case 233: /* mulld */
regs->gpr[rd] = regs->gpr[ra] * regs->gpr[rb];
goto arith_done;
#endif
case 234: /* addme */
add_with_carry(regs, rd, regs->gpr[ra], -1L,
regs->xer & XER_CA);
goto arith_done;
case 235: /* mullw */
regs->gpr[rd] = (unsigned int) regs->gpr[ra] *
(unsigned int) regs->gpr[rb];
goto arith_done;
case 266: /* add */
regs->gpr[rd] = regs->gpr[ra] + regs->gpr[rb];
goto arith_done;
#ifdef __powerpc64__
case 457: /* divdu */
regs->gpr[rd] = regs->gpr[ra] / regs->gpr[rb];
goto arith_done;
#endif
case 459: /* divwu */
regs->gpr[rd] = (unsigned int) regs->gpr[ra] /
(unsigned int) regs->gpr[rb];
goto arith_done;
#ifdef __powerpc64__
case 489: /* divd */
regs->gpr[rd] = (long int) regs->gpr[ra] /
(long int) regs->gpr[rb];
goto arith_done;
#endif
case 491: /* divw */
regs->gpr[rd] = (int) regs->gpr[ra] /
(int) regs->gpr[rb];
goto arith_done;
/*
* Logical instructions
*/
case 26: /* cntlzw */
asm("cntlzw %0,%1" : "=r" (regs->gpr[ra]) :
"r" (regs->gpr[rd]));
goto logical_done;
#ifdef __powerpc64__
case 58: /* cntlzd */
asm("cntlzd %0,%1" : "=r" (regs->gpr[ra]) :
"r" (regs->gpr[rd]));
goto logical_done;
#endif
case 28: /* and */
regs->gpr[ra] = regs->gpr[rd] & regs->gpr[rb];
goto logical_done;
case 60: /* andc */
regs->gpr[ra] = regs->gpr[rd] & ~regs->gpr[rb];
goto logical_done;
case 124: /* nor */
regs->gpr[ra] = ~(regs->gpr[rd] | regs->gpr[rb]);
goto logical_done;
case 284: /* xor */
regs->gpr[ra] = ~(regs->gpr[rd] ^ regs->gpr[rb]);
goto logical_done;
case 316: /* xor */
regs->gpr[ra] = regs->gpr[rd] ^ regs->gpr[rb];
goto logical_done;
case 412: /* orc */
regs->gpr[ra] = regs->gpr[rd] | ~regs->gpr[rb];
goto logical_done;
case 444: /* or */
regs->gpr[ra] = regs->gpr[rd] | regs->gpr[rb];
goto logical_done;
case 476: /* nand */
regs->gpr[ra] = ~(regs->gpr[rd] & regs->gpr[rb]);
goto logical_done;
case 922: /* extsh */
regs->gpr[ra] = (signed short) regs->gpr[rd];
goto logical_done;
case 954: /* extsb */
regs->gpr[ra] = (signed char) regs->gpr[rd];
goto logical_done;
#ifdef __powerpc64__
case 986: /* extsw */
regs->gpr[ra] = (signed int) regs->gpr[rd];
goto logical_done;
#endif
/*
* Shift instructions
*/
case 24: /* slw */
sh = regs->gpr[rb] & 0x3f;
if (sh < 32)
regs->gpr[ra] = (regs->gpr[rd] << sh) & 0xffffffffUL;
else
regs->gpr[ra] = 0;
goto logical_done;
case 536: /* srw */
sh = regs->gpr[rb] & 0x3f;
if (sh < 32)
regs->gpr[ra] = (regs->gpr[rd] & 0xffffffffUL) >> sh;
else
regs->gpr[ra] = 0;
goto logical_done;
case 792: /* sraw */
sh = regs->gpr[rb] & 0x3f;
ival = (signed int) regs->gpr[rd];
regs->gpr[ra] = ival >> (sh < 32 ? sh : 31);
if (ival < 0 && (sh >= 32 || (ival & ((1ul << sh) - 1)) != 0))
regs->xer |= XER_CA;
else
regs->xer &= ~XER_CA;
goto logical_done;
case 824: /* srawi */
sh = rb;
ival = (signed int) regs->gpr[rd];
regs->gpr[ra] = ival >> sh;
if (ival < 0 && (ival & ((1ul << sh) - 1)) != 0)
regs->xer |= XER_CA;
else
regs->xer &= ~XER_CA;
goto logical_done;
#ifdef __powerpc64__
case 27: /* sld */
sh = regs->gpr[rb] & 0x7f;
if (sh < 64)
regs->gpr[ra] = regs->gpr[rd] << sh;
else
regs->gpr[ra] = 0;
goto logical_done;
case 539: /* srd */
sh = regs->gpr[rb] & 0x7f;
if (sh < 64)
regs->gpr[ra] = regs->gpr[rd] >> sh;
else
regs->gpr[ra] = 0;
goto logical_done;
case 794: /* srad */
sh = regs->gpr[rb] & 0x7f;
ival = (signed long int) regs->gpr[rd];
regs->gpr[ra] = ival >> (sh < 64 ? sh : 63);
if (ival < 0 && (sh >= 64 || (ival & ((1ul << sh) - 1)) != 0))
regs->xer |= XER_CA;
else
regs->xer &= ~XER_CA;
goto logical_done;
case 826: /* sradi with sh_5 = 0 */
case 827: /* sradi with sh_5 = 1 */
sh = rb | ((instr & 2) << 4);
ival = (signed long int) regs->gpr[rd];
regs->gpr[ra] = ival >> sh;
if (ival < 0 && (ival & ((1ul << sh) - 1)) != 0)
regs->xer |= XER_CA;
else
regs->xer &= ~XER_CA;
goto logical_done;
#endif /* __powerpc64__ */
/*
* Cache instructions
*/
case 54: /* dcbst */
op->type = MKOP(CACHEOP, DCBST, 0);
op->ea = xform_ea(instr, regs);
return 0;
case 86: /* dcbf */
op->type = MKOP(CACHEOP, DCBF, 0);
op->ea = xform_ea(instr, regs);
return 0;
case 246: /* dcbtst */
op->type = MKOP(CACHEOP, DCBTST, 0);
op->ea = xform_ea(instr, regs);
op->reg = rd;
return 0;
case 278: /* dcbt */
op->type = MKOP(CACHEOP, DCBTST, 0);
op->ea = xform_ea(instr, regs);
op->reg = rd;
return 0;
case 982: /* icbi */
op->type = MKOP(CACHEOP, ICBI, 0);
op->ea = xform_ea(instr, regs);
return 0;
}
break;
}
/*
* Loads and stores.
*/
op->type = UNKNOWN;
op->update_reg = ra;
op->reg = rd;
op->val = regs->gpr[rd];
u = (instr >> 20) & UPDATE;
switch (opcode) {
case 31:
u = instr & UPDATE;
op->ea = xform_ea(instr, regs);
switch ((instr >> 1) & 0x3ff) {
case 20: /* lwarx */
op->type = MKOP(LARX, 0, 4);
break;
case 150: /* stwcx. */
op->type = MKOP(STCX, 0, 4);
break;
#ifdef __powerpc64__
case 84: /* ldarx */
op->type = MKOP(LARX, 0, 8);
break;
case 214: /* stdcx. */
op->type = MKOP(STCX, 0, 8);
break;
case 21: /* ldx */
case 53: /* ldux */
op->type = MKOP(LOAD, u, 8);
break;
#endif
case 23: /* lwzx */
case 55: /* lwzux */
op->type = MKOP(LOAD, u, 4);
break;
case 87: /* lbzx */
case 119: /* lbzux */
op->type = MKOP(LOAD, u, 1);
break;
#ifdef CONFIG_ALTIVEC
case 103: /* lvx */
case 359: /* lvxl */
if (!(regs->msr & MSR_VEC))
goto vecunavail;
op->type = MKOP(LOAD_VMX, 0, 16);
break;
case 231: /* stvx */
case 487: /* stvxl */
if (!(regs->msr & MSR_VEC))
goto vecunavail;
op->type = MKOP(STORE_VMX, 0, 16);
break;
#endif /* CONFIG_ALTIVEC */
#ifdef __powerpc64__
case 149: /* stdx */
case 181: /* stdux */
op->type = MKOP(STORE, u, 8);
break;
#endif
case 151: /* stwx */
case 183: /* stwux */
op->type = MKOP(STORE, u, 4);
break;
case 215: /* stbx */
case 247: /* stbux */
op->type = MKOP(STORE, u, 1);
break;
case 279: /* lhzx */
case 311: /* lhzux */
op->type = MKOP(LOAD, u, 2);
break;
#ifdef __powerpc64__
case 341: /* lwax */
case 373: /* lwaux */
op->type = MKOP(LOAD, SIGNEXT | u, 4);
break;
#endif
case 343: /* lhax */
case 375: /* lhaux */
op->type = MKOP(LOAD, SIGNEXT | u, 2);
break;
case 407: /* sthx */
case 439: /* sthux */
op->type = MKOP(STORE, u, 2);
break;
#ifdef __powerpc64__
case 532: /* ldbrx */
op->type = MKOP(LOAD, BYTEREV, 8);
break;
#endif
case 533: /* lswx */
op->type = MKOP(LOAD_MULTI, 0, regs->xer & 0x7f);
break;
case 534: /* lwbrx */
op->type = MKOP(LOAD, BYTEREV, 4);
break;
case 597: /* lswi */
if (rb == 0)
rb = 32; /* # bytes to load */
op->type = MKOP(LOAD_MULTI, 0, rb);
op->ea = 0;
if (ra)
op->ea = truncate_if_32bit(regs->msr,
regs->gpr[ra]);
break;
#ifdef CONFIG_PPC_FPU
case 535: /* lfsx */
case 567: /* lfsux */
if (!(regs->msr & MSR_FP))
goto fpunavail;
op->type = MKOP(LOAD_FP, u, 4);
break;
case 599: /* lfdx */
case 631: /* lfdux */
if (!(regs->msr & MSR_FP))
goto fpunavail;
op->type = MKOP(LOAD_FP, u, 8);
break;
case 663: /* stfsx */
case 695: /* stfsux */
if (!(regs->msr & MSR_FP))
goto fpunavail;
op->type = MKOP(STORE_FP, u, 4);
break;
case 727: /* stfdx */
case 759: /* stfdux */
if (!(regs->msr & MSR_FP))
goto fpunavail;
op->type = MKOP(STORE_FP, u, 8);
break;
#endif
#ifdef __powerpc64__
case 660: /* stdbrx */
op->type = MKOP(STORE, BYTEREV, 8);
op->val = byterev_8(regs->gpr[rd]);
break;
#endif
case 661: /* stswx */
op->type = MKOP(STORE_MULTI, 0, regs->xer & 0x7f);
break;
case 662: /* stwbrx */
op->type = MKOP(STORE, BYTEREV, 4);
op->val = byterev_4(regs->gpr[rd]);
break;
case 725:
if (rb == 0)
rb = 32; /* # bytes to store */
op->type = MKOP(STORE_MULTI, 0, rb);
op->ea = 0;
if (ra)
op->ea = truncate_if_32bit(regs->msr,
regs->gpr[ra]);
break;
case 790: /* lhbrx */
op->type = MKOP(LOAD, BYTEREV, 2);
break;
case 918: /* sthbrx */
op->type = MKOP(STORE, BYTEREV, 2);
op->val = byterev_2(regs->gpr[rd]);
break;
#ifdef CONFIG_VSX
case 844: /* lxvd2x */
case 876: /* lxvd2ux */
if (!(regs->msr & MSR_VSX))
goto vsxunavail;
op->reg = rd | ((instr & 1) << 5);
op->type = MKOP(LOAD_VSX, u, 16);
break;
case 972: /* stxvd2x */
case 1004: /* stxvd2ux */
if (!(regs->msr & MSR_VSX))
goto vsxunavail;
op->reg = rd | ((instr & 1) << 5);
op->type = MKOP(STORE_VSX, u, 16);
break;
#endif /* CONFIG_VSX */
}
break;
case 32: /* lwz */
case 33: /* lwzu */
op->type = MKOP(LOAD, u, 4);
op->ea = dform_ea(instr, regs);
break;
case 34: /* lbz */
case 35: /* lbzu */
op->type = MKOP(LOAD, u, 1);
op->ea = dform_ea(instr, regs);
break;
case 36: /* stw */
case 37: /* stwu */
op->type = MKOP(STORE, u, 4);
op->ea = dform_ea(instr, regs);
break;
case 38: /* stb */
case 39: /* stbu */
op->type = MKOP(STORE, u, 1);
op->ea = dform_ea(instr, regs);
break;
case 40: /* lhz */
case 41: /* lhzu */
op->type = MKOP(LOAD, u, 2);
op->ea = dform_ea(instr, regs);
break;
case 42: /* lha */
case 43: /* lhau */
op->type = MKOP(LOAD, SIGNEXT | u, 2);
op->ea = dform_ea(instr, regs);
break;
case 44: /* sth */
case 45: /* sthu */
op->type = MKOP(STORE, u, 2);
op->ea = dform_ea(instr, regs);
break;
case 46: /* lmw */
if (ra >= rd)
break; /* invalid form, ra in range to load */
op->type = MKOP(LOAD_MULTI, 0, 4 * (32 - rd));
op->ea = dform_ea(instr, regs);
break;
case 47: /* stmw */
op->type = MKOP(STORE_MULTI, 0, 4 * (32 - rd));
op->ea = dform_ea(instr, regs);
break;
#ifdef CONFIG_PPC_FPU
case 48: /* lfs */
case 49: /* lfsu */
if (!(regs->msr & MSR_FP))
goto fpunavail;
op->type = MKOP(LOAD_FP, u, 4);
op->ea = dform_ea(instr, regs);
break;
case 50: /* lfd */
case 51: /* lfdu */
if (!(regs->msr & MSR_FP))
goto fpunavail;
op->type = MKOP(LOAD_FP, u, 8);
op->ea = dform_ea(instr, regs);
break;
case 52: /* stfs */
case 53: /* stfsu */
if (!(regs->msr & MSR_FP))
goto fpunavail;
op->type = MKOP(STORE_FP, u, 4);
op->ea = dform_ea(instr, regs);
break;
case 54: /* stfd */
case 55: /* stfdu */
if (!(regs->msr & MSR_FP))
goto fpunavail;
op->type = MKOP(STORE_FP, u, 8);
op->ea = dform_ea(instr, regs);
break;
#endif
#ifdef __powerpc64__
case 58: /* ld[u], lwa */
op->ea = dsform_ea(instr, regs);
switch (instr & 3) {
case 0: /* ld */
op->type = MKOP(LOAD, 0, 8);
break;
case 1: /* ldu */
op->type = MKOP(LOAD, UPDATE, 8);
break;
case 2: /* lwa */
op->type = MKOP(LOAD, SIGNEXT, 4);
break;
}
break;
case 62: /* std[u] */
op->ea = dsform_ea(instr, regs);
switch (instr & 3) {
case 0: /* std */
op->type = MKOP(STORE, 0, 8);
break;
case 1: /* stdu */
op->type = MKOP(STORE, UPDATE, 8);
break;
}
break;
#endif /* __powerpc64__ */
}
return 0;
logical_done:
if (instr & 1)
set_cr0(regs, ra);
goto instr_done;
arith_done:
if (instr & 1)
set_cr0(regs, rd);
instr_done:
regs->nip = truncate_if_32bit(regs->msr, regs->nip + 4);
return 1;
priv:
op->type = INTERRUPT | 0x700;
op->val = SRR1_PROGPRIV;
return 0;
trap:
op->type = INTERRUPT | 0x700;
op->val = SRR1_PROGTRAP;
return 0;
#ifdef CONFIG_PPC_FPU
fpunavail:
op->type = INTERRUPT | 0x800;
return 0;
#endif
#ifdef CONFIG_ALTIVEC
vecunavail:
op->type = INTERRUPT | 0xf20;
return 0;
#endif
#ifdef CONFIG_VSX
vsxunavail:
op->type = INTERRUPT | 0xf40;
return 0;
#endif
}
EXPORT_SYMBOL_GPL(analyse_instr);
/*
* For PPC32 we always use stwu with r1 to change the stack pointer.
* So this emulated store may corrupt the exception frame, now we
* have to provide the exception frame trampoline, which is pushed
* below the kprobed function stack. So we only update gpr[1] but
* don't emulate the real store operation. We will do real store
* operation safely in exception return code by checking this flag.
*/
static __kprobes int handle_stack_update(unsigned long ea, struct pt_regs *regs)
{
#ifdef CONFIG_PPC32
/*
* Check if we will touch kernel stack overflow
*/
if (ea - STACK_INT_FRAME_SIZE <= current->thread.ksp_limit) {
printk(KERN_CRIT "Can't kprobe this since kernel stack would overflow.\n");
return -EINVAL;
}
#endif /* CONFIG_PPC32 */
/*
* Check if we already set since that means we'll
* lose the previous value.
*/
WARN_ON(test_thread_flag(TIF_EMULATE_STACK_STORE));
set_thread_flag(TIF_EMULATE_STACK_STORE);
return 0;
}
static __kprobes void do_signext(unsigned long *valp, int size)
{
switch (size) {
case 2:
*valp = (signed short) *valp;
break;
case 4:
*valp = (signed int) *valp;
break;
}
}
static __kprobes void do_byterev(unsigned long *valp, int size)
{
switch (size) {
case 2:
*valp = byterev_2(*valp);
break;
case 4:
*valp = byterev_4(*valp);
break;
#ifdef __powerpc64__
case 8:
*valp = byterev_8(*valp);
break;
#endif
}
}
/*
* Emulate instructions that cause a transfer of control,
* loads and stores, and a few other instructions.
* Returns 1 if the step was emulated, 0 if not,
* or -1 if the instruction is one that should not be stepped,
* such as an rfid, or a mtmsrd that would clear MSR_RI.
*/
int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
{
struct instruction_op op;
int r, err, size;
unsigned long val;
unsigned int cr;
int i, rd, nb;
r = analyse_instr(&op, regs, instr);
if (r != 0)
return r;
err = 0;
size = GETSIZE(op.type);
switch (op.type & INSTR_TYPE_MASK) {
case CACHEOP:
if (!address_ok(regs, op.ea, 8))
return 0;
switch (op.type & CACHEOP_MASK) {
case DCBST:
__cacheop_user_asmx(op.ea, err, "dcbst");
break;
case DCBF:
__cacheop_user_asmx(op.ea, err, "dcbf");
break;
case DCBTST:
if (op.reg == 0)
prefetchw((void *) op.ea);
break;
case DCBT:
if (op.reg == 0)
prefetch((void *) op.ea);
break;
case ICBI:
__cacheop_user_asmx(op.ea, err, "icbi");
break;
}
if (err)
return 0;
goto instr_done;
case LARX:
if (regs->msr & MSR_LE)
return 0;
if (op.ea & (size - 1))
break; /* can't handle misaligned */
err = -EFAULT;
if (!address_ok(regs, op.ea, size))
goto ldst_done;
err = 0;
switch (size) {
case 4:
__get_user_asmx(val, op.ea, err, "lwarx");
break;
#ifdef __powerpc64__
case 8:
__get_user_asmx(val, op.ea, err, "ldarx");
break;
#endif
default:
return 0;
}
if (!err)
regs->gpr[op.reg] = val;
goto ldst_done;
case STCX:
if (regs->msr & MSR_LE)
return 0;
if (op.ea & (size - 1))
break; /* can't handle misaligned */
err = -EFAULT;
if (!address_ok(regs, op.ea, size))
goto ldst_done;
err = 0;
switch (size) {
case 4:
__put_user_asmx(op.val, op.ea, err, "stwcx.", cr);
break;
#ifdef __powerpc64__
case 8:
__put_user_asmx(op.val, op.ea, err, "stdcx.", cr);
break;
#endif
default:
return 0;
}
if (!err)
regs->ccr = (regs->ccr & 0x0fffffff) |
(cr & 0xe0000000) |
((regs->xer >> 3) & 0x10000000);
goto ldst_done;
case LOAD:
if (regs->msr & MSR_LE)
return 0;
err = read_mem(&regs->gpr[op.reg], op.ea, size, regs);
if (!err) {
if (op.type & SIGNEXT)
do_signext(&regs->gpr[op.reg], size);
if (op.type & BYTEREV)
do_byterev(&regs->gpr[op.reg], size);
}
goto ldst_done;
#ifdef CONFIG_PPC_FPU
case LOAD_FP:
if (regs->msr & MSR_LE)
return 0;
if (size == 4)
err = do_fp_load(op.reg, do_lfs, op.ea, size, regs);
else
err = do_fp_load(op.reg, do_lfd, op.ea, size, regs);
goto ldst_done;
#endif
#ifdef CONFIG_ALTIVEC
case LOAD_VMX:
if (regs->msr & MSR_LE)
return 0;
err = do_vec_load(op.reg, do_lvx, op.ea & ~0xfUL, regs);
goto ldst_done;
#endif
#ifdef CONFIG_VSX
case LOAD_VSX:
if (regs->msr & MSR_LE)
return 0;
err = do_vsx_load(op.reg, do_lxvd2x, op.ea, regs);
goto ldst_done;
#endif
case LOAD_MULTI:
if (regs->msr & MSR_LE)
return 0;
rd = op.reg;
for (i = 0; i < size; i += 4) {
nb = size - i;
if (nb > 4)
nb = 4;
err = read_mem(&regs->gpr[rd], op.ea, nb, regs);
if (err)
return 0;
if (nb < 4) /* left-justify last bytes */
regs->gpr[rd] <<= 32 - 8 * nb;
op.ea += 4;
++rd;
}
goto instr_done;
case STORE:
if (regs->msr & MSR_LE)
return 0;
if ((op.type & UPDATE) && size == sizeof(long) &&
op.reg == 1 && op.update_reg == 1 &&
!(regs->msr & MSR_PR) &&
op.ea >= regs->gpr[1] - STACK_INT_FRAME_SIZE) {
err = handle_stack_update(op.ea, regs);
goto ldst_done;
}
err = write_mem(op.val, op.ea, size, regs);
goto ldst_done;
#ifdef CONFIG_PPC_FPU
case STORE_FP:
if (regs->msr & MSR_LE)
return 0;
if (size == 4)
err = do_fp_store(op.reg, do_stfs, op.ea, size, regs);
else
err = do_fp_store(op.reg, do_stfd, op.ea, size, regs);
goto ldst_done;
#endif
#ifdef CONFIG_ALTIVEC
case STORE_VMX:
if (regs->msr & MSR_LE)
return 0;
err = do_vec_store(op.reg, do_stvx, op.ea & ~0xfUL, regs);
goto ldst_done;
#endif
#ifdef CONFIG_VSX
case STORE_VSX:
if (regs->msr & MSR_LE)
return 0;
err = do_vsx_store(op.reg, do_stxvd2x, op.ea, regs);
goto ldst_done;
#endif
case STORE_MULTI:
if (regs->msr & MSR_LE)
return 0;
rd = op.reg;
for (i = 0; i < size; i += 4) {
val = regs->gpr[rd];
nb = size - i;
if (nb > 4)
nb = 4;
else
val >>= 32 - 8 * nb;
err = write_mem(val, op.ea, nb, regs);
if (err)
return 0;
op.ea += 4;
++rd;
}
goto instr_done;
case MFMSR:
regs->gpr[op.reg] = regs->msr & MSR_MASK;
goto instr_done;
case MTMSR:
val = regs->gpr[op.reg];
if ((val & MSR_RI) == 0)
/* can't step mtmsr[d] that would clear MSR_RI */
return -1;
/* here op.val is the mask of bits to change */
regs->msr = (regs->msr & ~op.val) | (val & op.val);
goto instr_done;
#ifdef CONFIG_PPC64
case SYSCALL: /* sc */
/*
* N.B. this uses knowledge about how the syscall
* entry code works. If that is changed, this will
* need to be changed also.
*/
if (regs->gpr[0] == 0x1ebe &&
cpu_has_feature(CPU_FTR_REAL_LE)) {
regs->msr ^= MSR_LE;
goto instr_done;
}
regs->gpr[9] = regs->gpr[13];
regs->gpr[10] = MSR_KERNEL;
regs->gpr[11] = regs->nip + 4;
regs->gpr[12] = regs->msr & MSR_MASK;
regs->gpr[13] = (unsigned long) get_paca();
regs->nip = (unsigned long) &system_call_common;
regs->msr = MSR_KERNEL;
return 1;
case RFI:
return -1;
#endif
}
return 0;
ldst_done:
if (err)
return 0;
if (op.type & UPDATE)
regs->gpr[op.update_reg] = op.ea;
instr_done:
regs->nip = truncate_if_32bit(regs->msr, regs->nip + 4);
return 1;
}
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