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linux/arch/arm/kernel/kprobes-decode.c
Jon Medhurst cdc2536115 ARM: kprobes: Tidy-up kprobes-decode.c 
- Remove coding standard violations reported by checkpatch.pl
- Delete comment about handling of conditional branches which is no
  longer true.
- Delete comment at end of file which lists all ARM instructions. This
  duplicates data available in the ARM ARM and seems like an
  unnecessary maintenance burden to keep this up to date and accurate.

Signed-off-by: Jon Medhurst <tixy@yxit.co.uk>
Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
2011-04-28 23:41:01 -04:00

1671 lines
51 KiB
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/*
* arch/arm/kernel/kprobes-decode.c
*
* Copyright (C) 2006, 2007 Motorola Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*/
/*
* We do not have hardware single-stepping on ARM, This
* effort is further complicated by the ARM not having a
* "next PC" register. Instructions that change the PC
* can't be safely single-stepped in a MP environment, so
* we have a lot of work to do:
*
* In the prepare phase:
* *) If it is an instruction that does anything
* with the CPU mode, we reject it for a kprobe.
* (This is out of laziness rather than need. The
* instructions could be simulated.)
*
* *) Otherwise, decode the instruction rewriting its
* registers to take fixed, ordered registers and
* setting a handler for it to run the instruction.
*
* In the execution phase by an instruction's handler:
*
* *) If the PC is written to by the instruction, the
* instruction must be fully simulated in software.
*
* *) Otherwise, a modified form of the instruction is
* directly executed. Its handler calls the
* instruction in insn[0]. In insn[1] is a
* "mov pc, lr" to return.
*
* Before calling, load up the reordered registers
* from the original instruction's registers. If one
* of the original input registers is the PC, compute
* and adjust the appropriate input register.
*
* After call completes, copy the output registers to
* the original instruction's original registers.
*
* We don't use a real breakpoint instruction since that
* would have us in the kernel go from SVC mode to SVC
* mode losing the link register. Instead we use an
* undefined instruction. To simplify processing, the
* undefined instruction used for kprobes must be reserved
* exclusively for kprobes use.
*
* TODO: ifdef out some instruction decoding based on architecture.
*/
#include <linux/kernel.h>
#include <linux/kprobes.h>
#define sign_extend(x, signbit) ((x) | (0 - ((x) & (1 << (signbit)))))
#define branch_displacement(insn) sign_extend(((insn) & 0xffffff) << 2, 25)
#define is_r15(insn, bitpos) (((insn) & (0xf << bitpos)) == (0xf << bitpos))
/*
* Test if load/store instructions writeback the address register.
* if P (bit 24) == 0 or W (bit 21) == 1
*/
#define is_writeback(insn) ((insn ^ 0x01000000) & 0x01200000)
#define PSR_fs (PSR_f|PSR_s)
#define KPROBE_RETURN_INSTRUCTION 0xe1a0f00e /* mov pc, lr */
typedef long (insn_0arg_fn_t)(void);
typedef long (insn_1arg_fn_t)(long);
typedef long (insn_2arg_fn_t)(long, long);
typedef long (insn_3arg_fn_t)(long, long, long);
typedef long (insn_4arg_fn_t)(long, long, long, long);
typedef long long (insn_llret_0arg_fn_t)(void);
typedef long long (insn_llret_3arg_fn_t)(long, long, long);
typedef long long (insn_llret_4arg_fn_t)(long, long, long, long);
union reg_pair {
long long dr;
#ifdef __LITTLE_ENDIAN
struct { long r0, r1; };
#else
struct { long r1, r0; };
#endif
};
/*
* For STR and STM instructions, an ARM core may choose to use either
* a +8 or a +12 displacement from the current instruction's address.
* Whichever value is chosen for a given core, it must be the same for
* both instructions and may not change. This function measures it.
*/
static int str_pc_offset;
static void __init find_str_pc_offset(void)
{
int addr, scratch, ret;
__asm__ (
"sub %[ret], pc, #4 \n\t"
"str pc, %[addr] \n\t"
"ldr %[scr], %[addr] \n\t"
"sub %[ret], %[scr], %[ret] \n\t"
: [ret] "=r" (ret), [scr] "=r" (scratch), [addr] "+m" (addr));
str_pc_offset = ret;
}
/*
* The insnslot_?arg_r[w]flags() functions below are to keep the
* msr -> *fn -> mrs instruction sequences indivisible so that
* the state of the CPSR flags aren't inadvertently modified
* just before or just after the call.
*/
static inline long __kprobes
insnslot_0arg_rflags(long cpsr, insn_0arg_fn_t *fn)
{
register long ret asm("r0");
__asm__ __volatile__ (
"msr cpsr_fs, %[cpsr] \n\t"
"mov lr, pc \n\t"
"mov pc, %[fn] \n\t"
: "=r" (ret)
: [cpsr] "r" (cpsr), [fn] "r" (fn)
: "lr", "cc"
);
return ret;
}
static inline long long __kprobes
insnslot_llret_0arg_rflags(long cpsr, insn_llret_0arg_fn_t *fn)
{
register long ret0 asm("r0");
register long ret1 asm("r1");
union reg_pair fnr;
__asm__ __volatile__ (
"msr cpsr_fs, %[cpsr] \n\t"
"mov lr, pc \n\t"
"mov pc, %[fn] \n\t"
: "=r" (ret0), "=r" (ret1)
: [cpsr] "r" (cpsr), [fn] "r" (fn)
: "lr", "cc"
);
fnr.r0 = ret0;
fnr.r1 = ret1;
return fnr.dr;
}
static inline long __kprobes
insnslot_1arg_rflags(long r0, long cpsr, insn_1arg_fn_t *fn)
{
register long rr0 asm("r0") = r0;
register long ret asm("r0");
__asm__ __volatile__ (
"msr cpsr_fs, %[cpsr] \n\t"
"mov lr, pc \n\t"
"mov pc, %[fn] \n\t"
: "=r" (ret)
: "0" (rr0), [cpsr] "r" (cpsr), [fn] "r" (fn)
: "lr", "cc"
);
return ret;
}
static inline long __kprobes
insnslot_2arg_rflags(long r0, long r1, long cpsr, insn_2arg_fn_t *fn)
{
register long rr0 asm("r0") = r0;
register long rr1 asm("r1") = r1;
register long ret asm("r0");
__asm__ __volatile__ (
"msr cpsr_fs, %[cpsr] \n\t"
"mov lr, pc \n\t"
"mov pc, %[fn] \n\t"
: "=r" (ret)
: "0" (rr0), "r" (rr1),
[cpsr] "r" (cpsr), [fn] "r" (fn)
: "lr", "cc"
);
return ret;
}
static inline long __kprobes
insnslot_3arg_rflags(long r0, long r1, long r2, long cpsr, insn_3arg_fn_t *fn)
{
register long rr0 asm("r0") = r0;
register long rr1 asm("r1") = r1;
register long rr2 asm("r2") = r2;
register long ret asm("r0");
__asm__ __volatile__ (
"msr cpsr_fs, %[cpsr] \n\t"
"mov lr, pc \n\t"
"mov pc, %[fn] \n\t"
: "=r" (ret)
: "0" (rr0), "r" (rr1), "r" (rr2),
[cpsr] "r" (cpsr), [fn] "r" (fn)
: "lr", "cc"
);
return ret;
}
static inline long long __kprobes
insnslot_llret_3arg_rflags(long r0, long r1, long r2, long cpsr,
insn_llret_3arg_fn_t *fn)
{
register long rr0 asm("r0") = r0;
register long rr1 asm("r1") = r1;
register long rr2 asm("r2") = r2;
register long ret0 asm("r0");
register long ret1 asm("r1");
union reg_pair fnr;
__asm__ __volatile__ (
"msr cpsr_fs, %[cpsr] \n\t"
"mov lr, pc \n\t"
"mov pc, %[fn] \n\t"
: "=r" (ret0), "=r" (ret1)
: "0" (rr0), "r" (rr1), "r" (rr2),
[cpsr] "r" (cpsr), [fn] "r" (fn)
: "lr", "cc"
);
fnr.r0 = ret0;
fnr.r1 = ret1;
return fnr.dr;
}
static inline long __kprobes
insnslot_4arg_rflags(long r0, long r1, long r2, long r3, long cpsr,
insn_4arg_fn_t *fn)
{
register long rr0 asm("r0") = r0;
register long rr1 asm("r1") = r1;
register long rr2 asm("r2") = r2;
register long rr3 asm("r3") = r3;
register long ret asm("r0");
__asm__ __volatile__ (
"msr cpsr_fs, %[cpsr] \n\t"
"mov lr, pc \n\t"
"mov pc, %[fn] \n\t"
: "=r" (ret)
: "0" (rr0), "r" (rr1), "r" (rr2), "r" (rr3),
[cpsr] "r" (cpsr), [fn] "r" (fn)
: "lr", "cc"
);
return ret;
}
static inline long __kprobes
insnslot_1arg_rwflags(long r0, long *cpsr, insn_1arg_fn_t *fn)
{
register long rr0 asm("r0") = r0;
register long ret asm("r0");
long oldcpsr = *cpsr;
long newcpsr;
__asm__ __volatile__ (
"msr cpsr_fs, %[oldcpsr] \n\t"
"mov lr, pc \n\t"
"mov pc, %[fn] \n\t"
"mrs %[newcpsr], cpsr \n\t"
: "=r" (ret), [newcpsr] "=r" (newcpsr)
: "0" (rr0), [oldcpsr] "r" (oldcpsr), [fn] "r" (fn)
: "lr", "cc"
);
*cpsr = (oldcpsr & ~PSR_fs) | (newcpsr & PSR_fs);
return ret;
}
static inline long __kprobes
insnslot_2arg_rwflags(long r0, long r1, long *cpsr, insn_2arg_fn_t *fn)
{
register long rr0 asm("r0") = r0;
register long rr1 asm("r1") = r1;
register long ret asm("r0");
long oldcpsr = *cpsr;
long newcpsr;
__asm__ __volatile__ (
"msr cpsr_fs, %[oldcpsr] \n\t"
"mov lr, pc \n\t"
"mov pc, %[fn] \n\t"
"mrs %[newcpsr], cpsr \n\t"
: "=r" (ret), [newcpsr] "=r" (newcpsr)
: "0" (rr0), "r" (rr1), [oldcpsr] "r" (oldcpsr), [fn] "r" (fn)
: "lr", "cc"
);
*cpsr = (oldcpsr & ~PSR_fs) | (newcpsr & PSR_fs);
return ret;
}
static inline long __kprobes
insnslot_3arg_rwflags(long r0, long r1, long r2, long *cpsr,
insn_3arg_fn_t *fn)
{
register long rr0 asm("r0") = r0;
register long rr1 asm("r1") = r1;
register long rr2 asm("r2") = r2;
register long ret asm("r0");
long oldcpsr = *cpsr;
long newcpsr;
__asm__ __volatile__ (
"msr cpsr_fs, %[oldcpsr] \n\t"
"mov lr, pc \n\t"
"mov pc, %[fn] \n\t"
"mrs %[newcpsr], cpsr \n\t"
: "=r" (ret), [newcpsr] "=r" (newcpsr)
: "0" (rr0), "r" (rr1), "r" (rr2),
[oldcpsr] "r" (oldcpsr), [fn] "r" (fn)
: "lr", "cc"
);
*cpsr = (oldcpsr & ~PSR_fs) | (newcpsr & PSR_fs);
return ret;
}
static inline long __kprobes
insnslot_4arg_rwflags(long r0, long r1, long r2, long r3, long *cpsr,
insn_4arg_fn_t *fn)
{
register long rr0 asm("r0") = r0;
register long rr1 asm("r1") = r1;
register long rr2 asm("r2") = r2;
register long rr3 asm("r3") = r3;
register long ret asm("r0");
long oldcpsr = *cpsr;
long newcpsr;
__asm__ __volatile__ (
"msr cpsr_fs, %[oldcpsr] \n\t"
"mov lr, pc \n\t"
"mov pc, %[fn] \n\t"
"mrs %[newcpsr], cpsr \n\t"
: "=r" (ret), [newcpsr] "=r" (newcpsr)
: "0" (rr0), "r" (rr1), "r" (rr2), "r" (rr3),
[oldcpsr] "r" (oldcpsr), [fn] "r" (fn)
: "lr", "cc"
);
*cpsr = (oldcpsr & ~PSR_fs) | (newcpsr & PSR_fs);
return ret;
}
static inline long long __kprobes
insnslot_llret_4arg_rwflags(long r0, long r1, long r2, long r3, long *cpsr,
insn_llret_4arg_fn_t *fn)
{
register long rr0 asm("r0") = r0;
register long rr1 asm("r1") = r1;
register long rr2 asm("r2") = r2;
register long rr3 asm("r3") = r3;
register long ret0 asm("r0");
register long ret1 asm("r1");
long oldcpsr = *cpsr;
long newcpsr;
union reg_pair fnr;
__asm__ __volatile__ (
"msr cpsr_fs, %[oldcpsr] \n\t"
"mov lr, pc \n\t"
"mov pc, %[fn] \n\t"
"mrs %[newcpsr], cpsr \n\t"
: "=r" (ret0), "=r" (ret1), [newcpsr] "=r" (newcpsr)
: "0" (rr0), "r" (rr1), "r" (rr2), "r" (rr3),
[oldcpsr] "r" (oldcpsr), [fn] "r" (fn)
: "lr", "cc"
);
*cpsr = (oldcpsr & ~PSR_fs) | (newcpsr & PSR_fs);
fnr.r0 = ret0;
fnr.r1 = ret1;
return fnr.dr;
}
/*
* To avoid the complications of mimicing single-stepping on a
* processor without a Next-PC or a single-step mode, and to
* avoid having to deal with the side-effects of boosting, we
* simulate or emulate (almost) all ARM instructions.
*
* "Simulation" is where the instruction's behavior is duplicated in
* C code. "Emulation" is where the original instruction is rewritten
* and executed, often by altering its registers.
*
* By having all behavior of the kprobe'd instruction completed before
* returning from the kprobe_handler(), all locks (scheduler and
* interrupt) can safely be released. There is no need for secondary
* breakpoints, no race with MP or preemptable kernels, nor having to
* clean up resources counts at a later time impacting overall system
* performance. By rewriting the instruction, only the minimum registers
* need to be loaded and saved back optimizing performance.
*
* Calling the insnslot_*_rwflags version of a function doesn't hurt
* anything even when the CPSR flags aren't updated by the
* instruction. It's just a little slower in return for saving
* a little space by not having a duplicate function that doesn't
* update the flags. (The same optimization can be said for
* instructions that do or don't perform register writeback)
* Also, instructions can either read the flags, only write the
* flags, or read and write the flags. To save combinations
* rather than for sheer performance, flag functions just assume
* read and write of flags.
*/
static void __kprobes simulate_bbl(struct kprobe *p, struct pt_regs *regs)
{
kprobe_opcode_t insn = p->opcode;
long iaddr = (long)p->addr;
int disp = branch_displacement(insn);
if (insn & (1 << 24))
regs->ARM_lr = iaddr + 4;
regs->ARM_pc = iaddr + 8 + disp;
}
static void __kprobes simulate_blx1(struct kprobe *p, struct pt_regs *regs)
{
kprobe_opcode_t insn = p->opcode;
long iaddr = (long)p->addr;
int disp = branch_displacement(insn);
regs->ARM_lr = iaddr + 4;
regs->ARM_pc = iaddr + 8 + disp + ((insn >> 23) & 0x2);
regs->ARM_cpsr |= PSR_T_BIT;
}
static void __kprobes simulate_blx2bx(struct kprobe *p, struct pt_regs *regs)
{
kprobe_opcode_t insn = p->opcode;
int rm = insn & 0xf;
long rmv = regs->uregs[rm];
if (insn & (1 << 5))
regs->ARM_lr = (long)p->addr + 4;
regs->ARM_pc = rmv & ~0x1;
regs->ARM_cpsr &= ~PSR_T_BIT;
if (rmv & 0x1)
regs->ARM_cpsr |= PSR_T_BIT;
}
static void __kprobes simulate_mrs(struct kprobe *p, struct pt_regs *regs)
{
kprobe_opcode_t insn = p->opcode;
int rd = (insn >> 12) & 0xf;
unsigned long mask = 0xf8ff03df; /* Mask out execution state */
regs->uregs[rd] = regs->ARM_cpsr & mask;
}
static void __kprobes simulate_ldm1stm1(struct kprobe *p, struct pt_regs *regs)
{
kprobe_opcode_t insn = p->opcode;
int rn = (insn >> 16) & 0xf;
int lbit = insn & (1 << 20);
int wbit = insn & (1 << 21);
int ubit = insn & (1 << 23);
int pbit = insn & (1 << 24);
long *addr = (long *)regs->uregs[rn];
int reg_bit_vector;
int reg_count;
reg_count = 0;
reg_bit_vector = insn & 0xffff;
while (reg_bit_vector) {
reg_bit_vector &= (reg_bit_vector - 1);
++reg_count;
}
if (!ubit)
addr -= reg_count;
addr += (!pbit == !ubit);
reg_bit_vector = insn & 0xffff;
while (reg_bit_vector) {
int reg = __ffs(reg_bit_vector);
reg_bit_vector &= (reg_bit_vector - 1);
if (lbit)
regs->uregs[reg] = *addr++;
else
*addr++ = regs->uregs[reg];
}
if (wbit) {
if (!ubit)
addr -= reg_count;
addr -= (!pbit == !ubit);
regs->uregs[rn] = (long)addr;
}
}
static void __kprobes simulate_stm1_pc(struct kprobe *p, struct pt_regs *regs)
{
regs->ARM_pc = (long)p->addr + str_pc_offset;
simulate_ldm1stm1(p, regs);
regs->ARM_pc = (long)p->addr + 4;
}
static void __kprobes simulate_mov_ipsp(struct kprobe *p, struct pt_regs *regs)
{
regs->uregs[12] = regs->uregs[13];
}
static void __kprobes emulate_ldrd(struct kprobe *p, struct pt_regs *regs)
{
insn_2arg_fn_t *i_fn = (insn_2arg_fn_t *)&p->ainsn.insn[0];
kprobe_opcode_t insn = p->opcode;
long ppc = (long)p->addr + 8;
int rd = (insn >> 12) & 0xf;
int rn = (insn >> 16) & 0xf;
int rm = insn & 0xf; /* rm may be invalid, don't care. */
long rmv = (rm == 15) ? ppc : regs->uregs[rm];
long rnv = (rn == 15) ? ppc : regs->uregs[rn];
/* Not following the C calling convention here, so need asm(). */
__asm__ __volatile__ (
"ldr r0, %[rn] \n\t"
"ldr r1, %[rm] \n\t"
"msr cpsr_fs, %[cpsr]\n\t"
"mov lr, pc \n\t"
"mov pc, %[i_fn] \n\t"
"str r0, %[rn] \n\t" /* in case of writeback */
"str r2, %[rd0] \n\t"
"str r3, %[rd1] \n\t"
: [rn] "+m" (rnv),
[rd0] "=m" (regs->uregs[rd]),
[rd1] "=m" (regs->uregs[rd+1])
: [rm] "m" (rmv),
[cpsr] "r" (regs->ARM_cpsr),
[i_fn] "r" (i_fn)
: "r0", "r1", "r2", "r3", "lr", "cc"
);
if (is_writeback(insn))
regs->uregs[rn] = rnv;
}
static void __kprobes emulate_strd(struct kprobe *p, struct pt_regs *regs)
{
insn_4arg_fn_t *i_fn = (insn_4arg_fn_t *)&p->ainsn.insn[0];
kprobe_opcode_t insn = p->opcode;
long ppc = (long)p->addr + 8;
int rd = (insn >> 12) & 0xf;
int rn = (insn >> 16) & 0xf;
int rm = insn & 0xf;
long rnv = (rn == 15) ? ppc : regs->uregs[rn];
/* rm/rmv may be invalid, don't care. */
long rmv = (rm == 15) ? ppc : regs->uregs[rm];
long rnv_wb;
rnv_wb = insnslot_4arg_rflags(rnv, rmv, regs->uregs[rd],
regs->uregs[rd+1],
regs->ARM_cpsr, i_fn);
if (is_writeback(insn))
regs->uregs[rn] = rnv_wb;
}
static void __kprobes emulate_ldr(struct kprobe *p, struct pt_regs *regs)
{
insn_llret_3arg_fn_t *i_fn = (insn_llret_3arg_fn_t *)&p->ainsn.insn[0];
kprobe_opcode_t insn = p->opcode;
long ppc = (long)p->addr + 8;
union reg_pair fnr;
int rd = (insn >> 12) & 0xf;
int rn = (insn >> 16) & 0xf;
int rm = insn & 0xf;
long rdv;
long rnv = (rn == 15) ? ppc : regs->uregs[rn];
long rmv = (rm == 15) ? ppc : regs->uregs[rm];
long cpsr = regs->ARM_cpsr;
fnr.dr = insnslot_llret_3arg_rflags(rnv, 0, rmv, cpsr, i_fn);
if (rn != 15)
regs->uregs[rn] = fnr.r0; /* Save Rn in case of writeback. */
rdv = fnr.r1;
if (rd == 15) {
#if __LINUX_ARM_ARCH__ >= 5
cpsr &= ~PSR_T_BIT;
if (rdv & 0x1)
cpsr |= PSR_T_BIT;
regs->ARM_cpsr = cpsr;
rdv &= ~0x1;
#else
rdv &= ~0x2;
#endif
}
regs->uregs[rd] = rdv;
}
static void __kprobes emulate_str(struct kprobe *p, struct pt_regs *regs)
{
insn_3arg_fn_t *i_fn = (insn_3arg_fn_t *)&p->ainsn.insn[0];
kprobe_opcode_t insn = p->opcode;
long iaddr = (long)p->addr;
int rd = (insn >> 12) & 0xf;
int rn = (insn >> 16) & 0xf;
int rm = insn & 0xf;
long rdv = (rd == 15) ? iaddr + str_pc_offset : regs->uregs[rd];
long rnv = (rn == 15) ? iaddr + 8 : regs->uregs[rn];
long rmv = regs->uregs[rm]; /* rm/rmv may be invalid, don't care. */
long rnv_wb;
rnv_wb = insnslot_3arg_rflags(rnv, rdv, rmv, regs->ARM_cpsr, i_fn);
if (rn != 15)
regs->uregs[rn] = rnv_wb; /* Save Rn in case of writeback. */
}
static void __kprobes emulate_sat(struct kprobe *p, struct pt_regs *regs)
{
insn_1arg_fn_t *i_fn = (insn_1arg_fn_t *)&p->ainsn.insn[0];
kprobe_opcode_t insn = p->opcode;
int rd = (insn >> 12) & 0xf;
int rm = insn & 0xf;
long rmv = regs->uregs[rm];
/* Writes Q flag */
regs->uregs[rd] = insnslot_1arg_rwflags(rmv, &regs->ARM_cpsr, i_fn);
}
static void __kprobes emulate_sel(struct kprobe *p, struct pt_regs *regs)
{
insn_2arg_fn_t *i_fn = (insn_2arg_fn_t *)&p->ainsn.insn[0];
kprobe_opcode_t insn = p->opcode;
int rd = (insn >> 12) & 0xf;
int rn = (insn >> 16) & 0xf;
int rm = insn & 0xf;
long rnv = regs->uregs[rn];
long rmv = regs->uregs[rm];
/* Reads GE bits */
regs->uregs[rd] = insnslot_2arg_rflags(rnv, rmv, regs->ARM_cpsr, i_fn);
}
static void __kprobes emulate_none(struct kprobe *p, struct pt_regs *regs)
{
insn_0arg_fn_t *i_fn = (insn_0arg_fn_t *)&p->ainsn.insn[0];
insnslot_0arg_rflags(regs->ARM_cpsr, i_fn);
}
static void __kprobes emulate_nop(struct kprobe *p, struct pt_regs *regs)
{
}
static void __kprobes
emulate_rd12_modify(struct kprobe *p, struct pt_regs *regs)
{
insn_1arg_fn_t *i_fn = (insn_1arg_fn_t *)&p->ainsn.insn[0];
kprobe_opcode_t insn = p->opcode;
int rd = (insn >> 12) & 0xf;
long rdv = regs->uregs[rd];
regs->uregs[rd] = insnslot_1arg_rflags(rdv, regs->ARM_cpsr, i_fn);
}
static void __kprobes
emulate_rd12rn0_modify(struct kprobe *p, struct pt_regs *regs)
{
insn_2arg_fn_t *i_fn = (insn_2arg_fn_t *)&p->ainsn.insn[0];
kprobe_opcode_t insn = p->opcode;
int rd = (insn >> 12) & 0xf;
int rn = insn & 0xf;
long rdv = regs->uregs[rd];
long rnv = regs->uregs[rn];
regs->uregs[rd] = insnslot_2arg_rflags(rdv, rnv, regs->ARM_cpsr, i_fn);
}
static void __kprobes emulate_rd12rm0(struct kprobe *p, struct pt_regs *regs)
{
insn_1arg_fn_t *i_fn = (insn_1arg_fn_t *)&p->ainsn.insn[0];
kprobe_opcode_t insn = p->opcode;
int rd = (insn >> 12) & 0xf;
int rm = insn & 0xf;
long rmv = regs->uregs[rm];
regs->uregs[rd] = insnslot_1arg_rflags(rmv, regs->ARM_cpsr, i_fn);
}
static void __kprobes
emulate_rd12rn16rm0_rwflags(struct kprobe *p, struct pt_regs *regs)
{
insn_2arg_fn_t *i_fn = (insn_2arg_fn_t *)&p->ainsn.insn[0];
kprobe_opcode_t insn = p->opcode;
int rd = (insn >> 12) & 0xf;
int rn = (insn >> 16) & 0xf;
int rm = insn & 0xf;
long rnv = regs->uregs[rn];
long rmv = regs->uregs[rm];
regs->uregs[rd] =
insnslot_2arg_rwflags(rnv, rmv, &regs->ARM_cpsr, i_fn);
}
static void __kprobes
emulate_rd16rn12rs8rm0_rwflags(struct kprobe *p, struct pt_regs *regs)
{
insn_3arg_fn_t *i_fn = (insn_3arg_fn_t *)&p->ainsn.insn[0];
kprobe_opcode_t insn = p->opcode;
int rd = (insn >> 16) & 0xf;
int rn = (insn >> 12) & 0xf;
int rs = (insn >> 8) & 0xf;
int rm = insn & 0xf;
long rnv = regs->uregs[rn];
long rsv = regs->uregs[rs];
long rmv = regs->uregs[rm];
regs->uregs[rd] =
insnslot_3arg_rwflags(rnv, rsv, rmv, &regs->ARM_cpsr, i_fn);
}
static void __kprobes
emulate_rd16rs8rm0_rwflags(struct kprobe *p, struct pt_regs *regs)
{
insn_2arg_fn_t *i_fn = (insn_2arg_fn_t *)&p->ainsn.insn[0];
kprobe_opcode_t insn = p->opcode;
int rd = (insn >> 16) & 0xf;
int rs = (insn >> 8) & 0xf;
int rm = insn & 0xf;
long rsv = regs->uregs[rs];
long rmv = regs->uregs[rm];
regs->uregs[rd] =
insnslot_2arg_rwflags(rsv, rmv, &regs->ARM_cpsr, i_fn);
}
static void __kprobes
emulate_rdhi16rdlo12rs8rm0_rwflags(struct kprobe *p, struct pt_regs *regs)
{
insn_llret_4arg_fn_t *i_fn = (insn_llret_4arg_fn_t *)&p->ainsn.insn[0];
kprobe_opcode_t insn = p->opcode;
union reg_pair fnr;
int rdhi = (insn >> 16) & 0xf;
int rdlo = (insn >> 12) & 0xf;
int rs = (insn >> 8) & 0xf;
int rm = insn & 0xf;
long rsv = regs->uregs[rs];
long rmv = regs->uregs[rm];
fnr.dr = insnslot_llret_4arg_rwflags(regs->uregs[rdhi],
regs->uregs[rdlo], rsv, rmv,
&regs->ARM_cpsr, i_fn);
regs->uregs[rdhi] = fnr.r0;
regs->uregs[rdlo] = fnr.r1;
}
static void __kprobes
emulate_alu_imm_rflags(struct kprobe *p, struct pt_regs *regs)
{
insn_1arg_fn_t *i_fn = (insn_1arg_fn_t *)&p->ainsn.insn[0];
kprobe_opcode_t insn = p->opcode;
int rd = (insn >> 12) & 0xf;
int rn = (insn >> 16) & 0xf;
long rnv = (rn == 15) ? (long)p->addr + 8 : regs->uregs[rn];
regs->uregs[rd] = insnslot_1arg_rflags(rnv, regs->ARM_cpsr, i_fn);
}
static void __kprobes
emulate_alu_imm_rwflags(struct kprobe *p, struct pt_regs *regs)
{
insn_1arg_fn_t *i_fn = (insn_1arg_fn_t *)&p->ainsn.insn[0];
kprobe_opcode_t insn = p->opcode;
int rd = (insn >> 12) & 0xf;
int rn = (insn >> 16) & 0xf;
long rnv = (rn == 15) ? (long)p->addr + 8 : regs->uregs[rn];
regs->uregs[rd] = insnslot_1arg_rwflags(rnv, &regs->ARM_cpsr, i_fn);
}
static void __kprobes
emulate_alu_tests_imm(struct kprobe *p, struct pt_regs *regs)
{
insn_1arg_fn_t *i_fn = (insn_1arg_fn_t *)&p->ainsn.insn[0];
kprobe_opcode_t insn = p->opcode;
int rn = (insn >> 16) & 0xf;
long rnv = (rn == 15) ? (long)p->addr + 8 : regs->uregs[rn];
insnslot_1arg_rwflags(rnv, &regs->ARM_cpsr, i_fn);
}
static void __kprobes
emulate_alu_rflags(struct kprobe *p, struct pt_regs *regs)
{
insn_3arg_fn_t *i_fn = (insn_3arg_fn_t *)&p->ainsn.insn[0];
kprobe_opcode_t insn = p->opcode;
long ppc = (long)p->addr + 8;
int rd = (insn >> 12) & 0xf;
int rn = (insn >> 16) & 0xf; /* rn/rnv/rs/rsv may be */
int rs = (insn >> 8) & 0xf; /* invalid, don't care. */
int rm = insn & 0xf;
long rnv = (rn == 15) ? ppc : regs->uregs[rn];
long rmv = (rm == 15) ? ppc : regs->uregs[rm];
long rsv = regs->uregs[rs];
regs->uregs[rd] =
insnslot_3arg_rflags(rnv, rmv, rsv, regs->ARM_cpsr, i_fn);
}
static void __kprobes
emulate_alu_rwflags(struct kprobe *p, struct pt_regs *regs)
{
insn_3arg_fn_t *i_fn = (insn_3arg_fn_t *)&p->ainsn.insn[0];
kprobe_opcode_t insn = p->opcode;
long ppc = (long)p->addr + 8;
int rd = (insn >> 12) & 0xf;
int rn = (insn >> 16) & 0xf; /* rn/rnv/rs/rsv may be */
int rs = (insn >> 8) & 0xf; /* invalid, don't care. */
int rm = insn & 0xf;
long rnv = (rn == 15) ? ppc : regs->uregs[rn];
long rmv = (rm == 15) ? ppc : regs->uregs[rm];
long rsv = regs->uregs[rs];
regs->uregs[rd] =
insnslot_3arg_rwflags(rnv, rmv, rsv, &regs->ARM_cpsr, i_fn);
}
static void __kprobes
emulate_alu_tests(struct kprobe *p, struct pt_regs *regs)
{
insn_3arg_fn_t *i_fn = (insn_3arg_fn_t *)&p->ainsn.insn[0];
kprobe_opcode_t insn = p->opcode;
long ppc = (long)p->addr + 8;
int rn = (insn >> 16) & 0xf;
int rs = (insn >> 8) & 0xf; /* rs/rsv may be invalid, don't care. */
int rm = insn & 0xf;
long rnv = (rn == 15) ? ppc : regs->uregs[rn];
long rmv = (rm == 15) ? ppc : regs->uregs[rm];
long rsv = regs->uregs[rs];
insnslot_3arg_rwflags(rnv, rmv, rsv, &regs->ARM_cpsr, i_fn);
}
static enum kprobe_insn __kprobes
prep_emulate_ldr_str(kprobe_opcode_t insn, struct arch_specific_insn *asi)
{
int not_imm = (insn & (1 << 26)) ? (insn & (1 << 25))
: (~insn & (1 << 22));
if (is_writeback(insn) && is_r15(insn, 16))
return INSN_REJECTED; /* Writeback to PC */
insn &= 0xfff00fff;
insn |= 0x00001000; /* Rn = r0, Rd = r1 */
if (not_imm) {
insn &= ~0xf;
insn |= 2; /* Rm = r2 */
}
asi->insn[0] = insn;
asi->insn_handler = (insn & (1 << 20)) ? emulate_ldr : emulate_str;
return INSN_GOOD;
}
static enum kprobe_insn __kprobes
prep_emulate_rd12_modify(kprobe_opcode_t insn, struct arch_specific_insn *asi)
{
if (is_r15(insn, 12))
return INSN_REJECTED; /* Rd is PC */
insn &= 0xffff0fff; /* Rd = r0 */
asi->insn[0] = insn;
asi->insn_handler = emulate_rd12_modify;
return INSN_GOOD;
}
static enum kprobe_insn __kprobes
prep_emulate_rd12rn0_modify(kprobe_opcode_t insn,
struct arch_specific_insn *asi)
{
if (is_r15(insn, 12))
return INSN_REJECTED; /* Rd is PC */
insn &= 0xffff0ff0; /* Rd = r0 */
insn |= 0x00000001; /* Rn = r1 */
asi->insn[0] = insn;
asi->insn_handler = emulate_rd12rn0_modify;
return INSN_GOOD;
}
static enum kprobe_insn __kprobes
prep_emulate_rd12rm0(kprobe_opcode_t insn, struct arch_specific_insn *asi)
{
if (is_r15(insn, 12))
return INSN_REJECTED; /* Rd is PC */
insn &= 0xffff0ff0; /* Rd = r0, Rm = r0 */
asi->insn[0] = insn;
asi->insn_handler = emulate_rd12rm0;
return INSN_GOOD;
}
static enum kprobe_insn __kprobes
prep_emulate_rd12rn16rm0_wflags(kprobe_opcode_t insn,
struct arch_specific_insn *asi)
{
if (is_r15(insn, 12))
return INSN_REJECTED; /* Rd is PC */
insn &= 0xfff00ff0; /* Rd = r0, Rn = r0 */
insn |= 0x00000001; /* Rm = r1 */
asi->insn[0] = insn;
asi->insn_handler = emulate_rd12rn16rm0_rwflags;
return INSN_GOOD;
}
static enum kprobe_insn __kprobes
prep_emulate_rd16rs8rm0_wflags(kprobe_opcode_t insn,
struct arch_specific_insn *asi)
{
if (is_r15(insn, 16))
return INSN_REJECTED; /* Rd is PC */
insn &= 0xfff0f0f0; /* Rd = r0, Rs = r0 */
insn |= 0x00000001; /* Rm = r1 */
asi->insn[0] = insn;
asi->insn_handler = emulate_rd16rs8rm0_rwflags;
return INSN_GOOD;
}
static enum kprobe_insn __kprobes
prep_emulate_rd16rn12rs8rm0_wflags(kprobe_opcode_t insn,
struct arch_specific_insn *asi)
{
if (is_r15(insn, 16))
return INSN_REJECTED; /* Rd is PC */
insn &= 0xfff000f0; /* Rd = r0, Rn = r0 */
insn |= 0x00000102; /* Rs = r1, Rm = r2 */
asi->insn[0] = insn;
asi->insn_handler = emulate_rd16rn12rs8rm0_rwflags;
return INSN_GOOD;
}
static enum kprobe_insn __kprobes
prep_emulate_rdhi16rdlo12rs8rm0_wflags(kprobe_opcode_t insn,
struct arch_specific_insn *asi)
{
if (is_r15(insn, 16) || is_r15(insn, 12))
return INSN_REJECTED; /* RdHi or RdLo is PC */
insn &= 0xfff000f0; /* RdHi = r0, RdLo = r1 */
insn |= 0x00001203; /* Rs = r2, Rm = r3 */
asi->insn[0] = insn;
asi->insn_handler = emulate_rdhi16rdlo12rs8rm0_rwflags;
return INSN_GOOD;
}
/*
* For the instruction masking and comparisons in all the "space_*"
* functions below, Do _not_ rearrange the order of tests unless
* you're very, very sure of what you are doing. For the sake of
* efficiency, the masks for some tests sometimes assume other test
* have been done prior to them so the number of patterns to test
* for an instruction set can be as broad as possible to reduce the
* number of tests needed.
*/
static enum kprobe_insn __kprobes
space_1111(kprobe_opcode_t insn, struct arch_specific_insn *asi)
{
/* memory hint : 1111 0100 x001 xxxx xxxx xxxx xxxx xxxx : */
/* PLDI : 1111 0100 x101 xxxx xxxx xxxx xxxx xxxx : */
/* PLDW : 1111 0101 x001 xxxx xxxx xxxx xxxx xxxx : */
/* PLD : 1111 0101 x101 xxxx xxxx xxxx xxxx xxxx : */
if ((insn & 0xfe300000) == 0xf4100000) {
asi->insn_handler = emulate_nop;
return INSN_GOOD_NO_SLOT;
}
/* BLX(1) : 1111 101x xxxx xxxx xxxx xxxx xxxx xxxx : */
if ((insn & 0xfe000000) == 0xfa000000) {
asi->insn_handler = simulate_blx1;
return INSN_GOOD_NO_SLOT;
}
/* CPS : 1111 0001 0000 xxx0 xxxx xxxx xx0x xxxx */
/* SETEND: 1111 0001 0000 0001 xxxx xxxx 0000 xxxx */
/* SRS : 1111 100x x1x0 xxxx xxxx xxxx xxxx xxxx */
/* RFE : 1111 100x x0x1 xxxx xxxx xxxx xxxx xxxx */
/* Coprocessor instructions... */
/* MCRR2 : 1111 1100 0100 xxxx xxxx xxxx xxxx xxxx : (Rd != Rn) */
/* MRRC2 : 1111 1100 0101 xxxx xxxx xxxx xxxx xxxx : (Rd != Rn) */
/* LDC2 : 1111 110x xxx1 xxxx xxxx xxxx xxxx xxxx */
/* STC2 : 1111 110x xxx0 xxxx xxxx xxxx xxxx xxxx */
/* CDP2 : 1111 1110 xxxx xxxx xxxx xxxx xxx0 xxxx */
/* MCR2 : 1111 1110 xxx0 xxxx xxxx xxxx xxx1 xxxx */
/* MRC2 : 1111 1110 xxx1 xxxx xxxx xxxx xxx1 xxxx */
return INSN_REJECTED;
}
static enum kprobe_insn __kprobes
space_cccc_000x(kprobe_opcode_t insn, struct arch_specific_insn *asi)
{
/* cccc 0001 0xx0 xxxx xxxx xxxx xxxx xxx0 xxxx */
if ((insn & 0x0f900010) == 0x01000000) {
/* MRS cpsr : cccc 0001 0000 xxxx xxxx xxxx 0000 xxxx */
if ((insn & 0x0ff000f0) == 0x01000000) {
if (is_r15(insn, 12))
return INSN_REJECTED; /* Rd is PC */
asi->insn_handler = simulate_mrs;
return INSN_GOOD_NO_SLOT;
}
/* SMLALxy : cccc 0001 0100 xxxx xxxx xxxx 1xx0 xxxx */
if ((insn & 0x0ff00090) == 0x01400080)
return prep_emulate_rdhi16rdlo12rs8rm0_wflags(insn,
asi);
/* SMULWy : cccc 0001 0010 xxxx xxxx xxxx 1x10 xxxx */
/* SMULxy : cccc 0001 0110 xxxx xxxx xxxx 1xx0 xxxx */
if ((insn & 0x0ff000b0) == 0x012000a0 ||
(insn & 0x0ff00090) == 0x01600080)
return prep_emulate_rd16rs8rm0_wflags(insn, asi);
/* SMLAxy : cccc 0001 0000 xxxx xxxx xxxx 1xx0 xxxx : Q */
/* SMLAWy : cccc 0001 0010 xxxx xxxx xxxx 1x00 xxxx : Q */
if ((insn & 0x0ff00090) == 0x01000080 ||
(insn & 0x0ff000b0) == 0x01200080)
return prep_emulate_rd16rn12rs8rm0_wflags(insn, asi);
/* BXJ : cccc 0001 0010 xxxx xxxx xxxx 0010 xxxx */
/* MSR : cccc 0001 0x10 xxxx xxxx xxxx 0000 xxxx */
/* MRS spsr : cccc 0001 0100 xxxx xxxx xxxx 0000 xxxx */
/* Other instruction encodings aren't yet defined */
return INSN_REJECTED;
}
/* cccc 0001 0xx0 xxxx xxxx xxxx xxxx 0xx1 xxxx */
else if ((insn & 0x0f900090) == 0x01000010) {
/* BLX(2) : cccc 0001 0010 xxxx xxxx xxxx 0011 xxxx */
/* BX : cccc 0001 0010 xxxx xxxx xxxx 0001 xxxx */
if ((insn & 0x0ff000d0) == 0x01200010) {
if ((insn & 0x0ff000ff) == 0x0120003f)
return INSN_REJECTED; /* BLX pc */
asi->insn_handler = simulate_blx2bx;
return INSN_GOOD_NO_SLOT;
}
/* CLZ : cccc 0001 0110 xxxx xxxx xxxx 0001 xxxx */
if ((insn & 0x0ff000f0) == 0x01600010)
return prep_emulate_rd12rm0(insn, asi);
/* QADD : cccc 0001 0000 xxxx xxxx xxxx 0101 xxxx :Q */
/* QSUB : cccc 0001 0010 xxxx xxxx xxxx 0101 xxxx :Q */
/* QDADD : cccc 0001 0100 xxxx xxxx xxxx 0101 xxxx :Q */
/* QDSUB : cccc 0001 0110 xxxx xxxx xxxx 0101 xxxx :Q */
if ((insn & 0x0f9000f0) == 0x01000050)
return prep_emulate_rd12rn16rm0_wflags(insn, asi);
/* BKPT : 1110 0001 0010 xxxx xxxx xxxx 0111 xxxx */
/* SMC : cccc 0001 0110 xxxx xxxx xxxx 0111 xxxx */
/* Other instruction encodings aren't yet defined */
return INSN_REJECTED;
}
/* cccc 0000 xxxx xxxx xxxx xxxx xxxx 1001 xxxx */
else if ((insn & 0x0f0000f0) == 0x00000090) {
/* MUL : cccc 0000 0000 xxxx xxxx xxxx 1001 xxxx : */
/* MULS : cccc 0000 0001 xxxx xxxx xxxx 1001 xxxx :cc */
/* MLA : cccc 0000 0010 xxxx xxxx xxxx 1001 xxxx : */
/* MLAS : cccc 0000 0011 xxxx xxxx xxxx 1001 xxxx :cc */
/* UMAAL : cccc 0000 0100 xxxx xxxx xxxx 1001 xxxx : */
/* undef : cccc 0000 0101 xxxx xxxx xxxx 1001 xxxx : */
/* MLS : cccc 0000 0110 xxxx xxxx xxxx 1001 xxxx : */
/* undef : cccc 0000 0111 xxxx xxxx xxxx 1001 xxxx : */
/* UMULL : cccc 0000 1000 xxxx xxxx xxxx 1001 xxxx : */
/* UMULLS : cccc 0000 1001 xxxx xxxx xxxx 1001 xxxx :cc */
/* UMLAL : cccc 0000 1010 xxxx xxxx xxxx 1001 xxxx : */
/* UMLALS : cccc 0000 1011 xxxx xxxx xxxx 1001 xxxx :cc */
/* SMULL : cccc 0000 1100 xxxx xxxx xxxx 1001 xxxx : */
/* SMULLS : cccc 0000 1101 xxxx xxxx xxxx 1001 xxxx :cc */
/* SMLAL : cccc 0000 1110 xxxx xxxx xxxx 1001 xxxx : */
/* SMLALS : cccc 0000 1111 xxxx xxxx xxxx 1001 xxxx :cc */
if ((insn & 0x00d00000) == 0x00500000)
return INSN_REJECTED;
else if ((insn & 0x00e00000) == 0x00000000)
return prep_emulate_rd16rs8rm0_wflags(insn, asi);
else if ((insn & 0x00a00000) == 0x00200000)
return prep_emulate_rd16rn12rs8rm0_wflags(insn, asi);
else
return prep_emulate_rdhi16rdlo12rs8rm0_wflags(insn,
asi);
}
/* cccc 000x xxxx xxxx xxxx xxxx xxxx 1xx1 xxxx */
else if ((insn & 0x0e000090) == 0x00000090) {
/* SWP : cccc 0001 0000 xxxx xxxx xxxx 1001 xxxx */
/* SWPB : cccc 0001 0100 xxxx xxxx xxxx 1001 xxxx */
/* ??? : cccc 0001 0x01 xxxx xxxx xxxx 1001 xxxx */
/* ??? : cccc 0001 0x10 xxxx xxxx xxxx 1001 xxxx */
/* ??? : cccc 0001 0x11 xxxx xxxx xxxx 1001 xxxx */
/* STREX : cccc 0001 1000 xxxx xxxx xxxx 1001 xxxx */
/* LDREX : cccc 0001 1001 xxxx xxxx xxxx 1001 xxxx */
/* STREXD: cccc 0001 1010 xxxx xxxx xxxx 1001 xxxx */
/* LDREXD: cccc 0001 1011 xxxx xxxx xxxx 1001 xxxx */
/* STREXB: cccc 0001 1100 xxxx xxxx xxxx 1001 xxxx */
/* LDREXB: cccc 0001 1101 xxxx xxxx xxxx 1001 xxxx */
/* STREXH: cccc 0001 1110 xxxx xxxx xxxx 1001 xxxx */
/* LDREXH: cccc 0001 1111 xxxx xxxx xxxx 1001 xxxx */
/* LDRD : cccc 000x xxx0 xxxx xxxx xxxx 1101 xxxx */
/* STRD : cccc 000x xxx0 xxxx xxxx xxxx 1111 xxxx */
/* LDRH : cccc 000x xxx1 xxxx xxxx xxxx 1011 xxxx */
/* STRH : cccc 000x xxx0 xxxx xxxx xxxx 1011 xxxx */
/* LDRSB : cccc 000x xxx1 xxxx xxxx xxxx 1101 xxxx */
/* LDRSH : cccc 000x xxx1 xxxx xxxx xxxx 1111 xxxx */
if ((insn & 0x0f0000f0) == 0x01000090) {
if ((insn & 0x0fb000f0) == 0x01000090) {
/* SWP/SWPB */
return prep_emulate_rd12rn16rm0_wflags(insn,
asi);
} else {
/* STREX/LDREX variants and unallocaed space */
return INSN_REJECTED;
}
} else if ((insn & 0x0e1000d0) == 0x00000d0) {
/* STRD/LDRD */
if ((insn & 0x0000e000) == 0x0000e000)
return INSN_REJECTED; /* Rd is LR or PC */
if (is_writeback(insn) && is_r15(insn, 16))
return INSN_REJECTED; /* Writeback to PC */
insn &= 0xfff00fff;
insn |= 0x00002000; /* Rn = r0, Rd = r2 */
if (!(insn & (1 << 22))) {
/* Register index */
insn &= ~0xf;
insn |= 1; /* Rm = r1 */
}
asi->insn[0] = insn;
asi->insn_handler =
(insn & (1 << 5)) ? emulate_strd : emulate_ldrd;
return INSN_GOOD;
}
/* LDRH/STRH/LDRSB/LDRSH */
if (is_r15(insn, 12))
return INSN_REJECTED; /* Rd is PC */
return prep_emulate_ldr_str(insn, asi);
}
/* cccc 000x xxxx xxxx xxxx xxxx xxxx xxxx xxxx */
/*
* ALU op with S bit and Rd == 15 :
* cccc 000x xxx1 xxxx 1111 xxxx xxxx xxxx
*/
if ((insn & 0x0e10f000) == 0x0010f000)
return INSN_REJECTED;
/*
* "mov ip, sp" is the most common kprobe'd instruction by far.
* Check and optimize for it explicitly.
*/
if (insn == 0xe1a0c00d) {
asi->insn_handler = simulate_mov_ipsp;
return INSN_GOOD_NO_SLOT;
}
/*
* Data processing: Immediate-shift / Register-shift
* ALU op : cccc 000x xxxx xxxx xxxx xxxx xxxx xxxx
* CPY : cccc 0001 1010 xxxx xxxx 0000 0000 xxxx
* MOV : cccc 0001 101x xxxx xxxx xxxx xxxx xxxx
* *S (bit 20) updates condition codes
* ADC/SBC/RSC reads the C flag
*/
insn &= 0xfff00ff0; /* Rn = r0, Rd = r0 */
insn |= 0x00000001; /* Rm = r1 */
if (insn & 0x010) {
insn &= 0xfffff0ff; /* register shift */
insn |= 0x00000200; /* Rs = r2 */
}
asi->insn[0] = insn;
if ((insn & 0x0f900000) == 0x01100000) {
/*
* TST : cccc 0001 0001 xxxx xxxx xxxx xxxx xxxx
* TEQ : cccc 0001 0011 xxxx xxxx xxxx xxxx xxxx
* CMP : cccc 0001 0101 xxxx xxxx xxxx xxxx xxxx
* CMN : cccc 0001 0111 xxxx xxxx xxxx xxxx xxxx
*/
asi->insn_handler = emulate_alu_tests;
} else {
/* ALU ops which write to Rd */
asi->insn_handler = (insn & (1 << 20)) ? /* S-bit */
emulate_alu_rwflags : emulate_alu_rflags;
}
return INSN_GOOD;
}
static enum kprobe_insn __kprobes
space_cccc_001x(kprobe_opcode_t insn, struct arch_specific_insn *asi)
{
/* MOVW : cccc 0011 0000 xxxx xxxx xxxx xxxx xxxx */
/* MOVT : cccc 0011 0100 xxxx xxxx xxxx xxxx xxxx */
if ((insn & 0x0fb00000) == 0x03000000)
return prep_emulate_rd12_modify(insn, asi);
/* hints : cccc 0011 0010 0000 xxxx xxxx xxxx xxxx */
if ((insn & 0x0fff0000) == 0x03200000) {
unsigned op2 = insn & 0x000000ff;
if (op2 == 0x01 || op2 == 0x04) {
/* YIELD : cccc 0011 0010 0000 xxxx xxxx 0000 0001 */
/* SEV : cccc 0011 0010 0000 xxxx xxxx 0000 0100 */
asi->insn[0] = insn;
asi->insn_handler = emulate_none;
return INSN_GOOD;
} else if (op2 <= 0x03) {
/* NOP : cccc 0011 0010 0000 xxxx xxxx 0000 0000 */
/* WFE : cccc 0011 0010 0000 xxxx xxxx 0000 0010 */
/* WFI : cccc 0011 0010 0000 xxxx xxxx 0000 0011 */
/*
* We make WFE and WFI true NOPs to avoid stalls due
* to missing events whilst processing the probe.
*/
asi->insn_handler = emulate_nop;
return INSN_GOOD_NO_SLOT;
}
/* For DBG and unallocated hints it's safest to reject them */
return INSN_REJECTED;
}
/*
* MSR : cccc 0011 0x10 xxxx xxxx xxxx xxxx xxxx
* ALU op with S bit and Rd == 15 :
* cccc 001x xxx1 xxxx 1111 xxxx xxxx xxxx
*/
if ((insn & 0x0fb00000) == 0x03200000 || /* MSR */
(insn & 0x0e10f000) == 0x0210f000) /* ALU s-bit, R15 */
return INSN_REJECTED;
/*
* Data processing: 32-bit Immediate
* ALU op : cccc 001x xxxx xxxx xxxx xxxx xxxx xxxx
* MOV : cccc 0011 101x xxxx xxxx xxxx xxxx xxxx
* *S (bit 20) updates condition codes
* ADC/SBC/RSC reads the C flag
*/
insn &= 0xfff00fff; /* Rn = r0 and Rd = r0 */
asi->insn[0] = insn;
if ((insn & 0x0f900000) == 0x03100000) {
/*
* TST : cccc 0011 0001 xxxx xxxx xxxx xxxx xxxx
* TEQ : cccc 0011 0011 xxxx xxxx xxxx xxxx xxxx
* CMP : cccc 0011 0101 xxxx xxxx xxxx xxxx xxxx
* CMN : cccc 0011 0111 xxxx xxxx xxxx xxxx xxxx
*/
asi->insn_handler = emulate_alu_tests_imm;
} else {
/* ALU ops which write to Rd */
asi->insn_handler = (insn & (1 << 20)) ? /* S-bit */
emulate_alu_imm_rwflags : emulate_alu_imm_rflags;
}
return INSN_GOOD;
}
static enum kprobe_insn __kprobes
space_cccc_0110__1(kprobe_opcode_t insn, struct arch_specific_insn *asi)
{
/* SEL : cccc 0110 1000 xxxx xxxx xxxx 1011 xxxx GE: !!! */
if ((insn & 0x0ff000f0) == 0x068000b0) {
if (is_r15(insn, 12))
return INSN_REJECTED; /* Rd is PC */
insn &= 0xfff00ff0; /* Rd = r0, Rn = r0 */
insn |= 0x00000001; /* Rm = r1 */
asi->insn[0] = insn;
asi->insn_handler = emulate_sel;
return INSN_GOOD;
}
/* SSAT : cccc 0110 101x xxxx xxxx xxxx xx01 xxxx :Q */
/* USAT : cccc 0110 111x xxxx xxxx xxxx xx01 xxxx :Q */
/* SSAT16 : cccc 0110 1010 xxxx xxxx xxxx 0011 xxxx :Q */
/* USAT16 : cccc 0110 1110 xxxx xxxx xxxx 0011 xxxx :Q */
if ((insn & 0x0fa00030) == 0x06a00010 ||
(insn & 0x0fb000f0) == 0x06a00030) {
if (is_r15(insn, 12))
return INSN_REJECTED; /* Rd is PC */
insn &= 0xffff0ff0; /* Rd = r0, Rm = r0 */
asi->insn[0] = insn;
asi->insn_handler = emulate_sat;
return INSN_GOOD;
}
/* REV : cccc 0110 1011 xxxx xxxx xxxx 0011 xxxx */
/* REV16 : cccc 0110 1011 xxxx xxxx xxxx 1011 xxxx */
/* RBIT : cccc 0110 1111 xxxx xxxx xxxx 0011 xxxx */
/* REVSH : cccc 0110 1111 xxxx xxxx xxxx 1011 xxxx */
if ((insn & 0x0ff00070) == 0x06b00030 ||
(insn & 0x0ff00070) == 0x06f00030)
return prep_emulate_rd12rm0(insn, asi);
/* ??? : cccc 0110 0000 xxxx xxxx xxxx xxx1 xxxx : */
/* SADD16 : cccc 0110 0001 xxxx xxxx xxxx 0001 xxxx :GE */
/* SADDSUBX : cccc 0110 0001 xxxx xxxx xxxx 0011 xxxx :GE */
/* SSUBADDX : cccc 0110 0001 xxxx xxxx xxxx 0101 xxxx :GE */
/* SSUB16 : cccc 0110 0001 xxxx xxxx xxxx 0111 xxxx :GE */
/* SADD8 : cccc 0110 0001 xxxx xxxx xxxx 1001 xxxx :GE */
/* ??? : cccc 0110 0001 xxxx xxxx xxxx 1011 xxxx : */
/* ??? : cccc 0110 0001 xxxx xxxx xxxx 1101 xxxx : */
/* SSUB8 : cccc 0110 0001 xxxx xxxx xxxx 1111 xxxx :GE */
/* QADD16 : cccc 0110 0010 xxxx xxxx xxxx 0001 xxxx : */
/* QADDSUBX : cccc 0110 0010 xxxx xxxx xxxx 0011 xxxx : */
/* QSUBADDX : cccc 0110 0010 xxxx xxxx xxxx 0101 xxxx : */
/* QSUB16 : cccc 0110 0010 xxxx xxxx xxxx 0111 xxxx : */
/* QADD8 : cccc 0110 0010 xxxx xxxx xxxx 1001 xxxx : */
/* ??? : cccc 0110 0010 xxxx xxxx xxxx 1011 xxxx : */
/* ??? : cccc 0110 0010 xxxx xxxx xxxx 1101 xxxx : */
/* QSUB8 : cccc 0110 0010 xxxx xxxx xxxx 1111 xxxx : */
/* SHADD16 : cccc 0110 0011 xxxx xxxx xxxx 0001 xxxx : */
/* SHADDSUBX : cccc 0110 0011 xxxx xxxx xxxx 0011 xxxx : */
/* SHSUBADDX : cccc 0110 0011 xxxx xxxx xxxx 0101 xxxx : */
/* SHSUB16 : cccc 0110 0011 xxxx xxxx xxxx 0111 xxxx : */
/* SHADD8 : cccc 0110 0011 xxxx xxxx xxxx 1001 xxxx : */
/* ??? : cccc 0110 0011 xxxx xxxx xxxx 1011 xxxx : */
/* ??? : cccc 0110 0011 xxxx xxxx xxxx 1101 xxxx : */
/* SHSUB8 : cccc 0110 0011 xxxx xxxx xxxx 1111 xxxx : */
/* ??? : cccc 0110 0100 xxxx xxxx xxxx xxx1 xxxx : */
/* UADD16 : cccc 0110 0101 xxxx xxxx xxxx 0001 xxxx :GE */
/* UADDSUBX : cccc 0110 0101 xxxx xxxx xxxx 0011 xxxx :GE */
/* USUBADDX : cccc 0110 0101 xxxx xxxx xxxx 0101 xxxx :GE */
/* USUB16 : cccc 0110 0101 xxxx xxxx xxxx 0111 xxxx :GE */
/* UADD8 : cccc 0110 0101 xxxx xxxx xxxx 1001 xxxx :GE */
/* ??? : cccc 0110 0101 xxxx xxxx xxxx 1011 xxxx : */
/* ??? : cccc 0110 0101 xxxx xxxx xxxx 1101 xxxx : */
/* USUB8 : cccc 0110 0101 xxxx xxxx xxxx 1111 xxxx :GE */
/* UQADD16 : cccc 0110 0110 xxxx xxxx xxxx 0001 xxxx : */
/* UQADDSUBX : cccc 0110 0110 xxxx xxxx xxxx 0011 xxxx : */
/* UQSUBADDX : cccc 0110 0110 xxxx xxxx xxxx 0101 xxxx : */
/* UQSUB16 : cccc 0110 0110 xxxx xxxx xxxx 0111 xxxx : */
/* UQADD8 : cccc 0110 0110 xxxx xxxx xxxx 1001 xxxx : */
/* ??? : cccc 0110 0110 xxxx xxxx xxxx 1011 xxxx : */
/* ??? : cccc 0110 0110 xxxx xxxx xxxx 1101 xxxx : */
/* UQSUB8 : cccc 0110 0110 xxxx xxxx xxxx 1111 xxxx : */
/* UHADD16 : cccc 0110 0111 xxxx xxxx xxxx 0001 xxxx : */
/* UHADDSUBX : cccc 0110 0111 xxxx xxxx xxxx 0011 xxxx : */
/* UHSUBADDX : cccc 0110 0111 xxxx xxxx xxxx 0101 xxxx : */
/* UHSUB16 : cccc 0110 0111 xxxx xxxx xxxx 0111 xxxx : */
/* UHADD8 : cccc 0110 0111 xxxx xxxx xxxx 1001 xxxx : */
/* ??? : cccc 0110 0111 xxxx xxxx xxxx 1011 xxxx : */
/* ??? : cccc 0110 0111 xxxx xxxx xxxx 1101 xxxx : */
/* UHSUB8 : cccc 0110 0111 xxxx xxxx xxxx 1111 xxxx : */
if ((insn & 0x0f800010) == 0x06000010) {
if ((insn & 0x00300000) == 0x00000000 ||
(insn & 0x000000e0) == 0x000000a0 ||
(insn & 0x000000e0) == 0x000000c0)
return INSN_REJECTED; /* Unallocated space */
return prep_emulate_rd12rn16rm0_wflags(insn, asi);
}
/* PKHBT : cccc 0110 1000 xxxx xxxx xxxx x001 xxxx : */
/* PKHTB : cccc 0110 1000 xxxx xxxx xxxx x101 xxxx : */
if ((insn & 0x0ff00030) == 0x06800010)
return prep_emulate_rd12rn16rm0_wflags(insn, asi);
/* SXTAB16 : cccc 0110 1000 xxxx xxxx xxxx 0111 xxxx : */
/* SXTB16 : cccc 0110 1000 1111 xxxx xxxx 0111 xxxx : */
/* ??? : cccc 0110 1001 xxxx xxxx xxxx 0111 xxxx : */
/* SXTAB : cccc 0110 1010 xxxx xxxx xxxx 0111 xxxx : */
/* SXTB : cccc 0110 1010 1111 xxxx xxxx 0111 xxxx : */
/* SXTAH : cccc 0110 1011 xxxx xxxx xxxx 0111 xxxx : */
/* SXTH : cccc 0110 1011 1111 xxxx xxxx 0111 xxxx : */
/* UXTAB16 : cccc 0110 1100 xxxx xxxx xxxx 0111 xxxx : */
/* UXTB16 : cccc 0110 1100 1111 xxxx xxxx 0111 xxxx : */
/* ??? : cccc 0110 1101 xxxx xxxx xxxx 0111 xxxx : */
/* UXTAB : cccc 0110 1110 xxxx xxxx xxxx 0111 xxxx : */
/* UXTB : cccc 0110 1110 1111 xxxx xxxx 0111 xxxx : */
/* UXTAH : cccc 0110 1111 xxxx xxxx xxxx 0111 xxxx : */
/* UXTH : cccc 0110 1111 1111 xxxx xxxx 0111 xxxx : */
if ((insn & 0x0f8000f0) == 0x06800070) {
if ((insn & 0x00300000) == 0x00100000)
return INSN_REJECTED; /* Unallocated space */
if ((insn & 0x000f0000) == 0x000f0000)
return prep_emulate_rd12rm0(insn, asi);
else
return prep_emulate_rd12rn16rm0_wflags(insn, asi);
}
/* Other instruction encodings aren't yet defined */
return INSN_REJECTED;
}
static enum kprobe_insn __kprobes
space_cccc_0111__1(kprobe_opcode_t insn, struct arch_specific_insn *asi)
{
/* Undef : cccc 0111 1111 xxxx xxxx xxxx 1111 xxxx */
if ((insn & 0x0ff000f0) == 0x03f000f0)
return INSN_REJECTED;
/* SMLALD : cccc 0111 0100 xxxx xxxx xxxx 00x1 xxxx */
/* SMLSLD : cccc 0111 0100 xxxx xxxx xxxx 01x1 xxxx */
if ((insn & 0x0ff00090) == 0x07400010)
return prep_emulate_rdhi16rdlo12rs8rm0_wflags(insn, asi);
/* SMLAD : cccc 0111 0000 xxxx xxxx xxxx 00x1 xxxx :Q */
/* SMUAD : cccc 0111 0000 xxxx 1111 xxxx 00x1 xxxx :Q */
/* SMLSD : cccc 0111 0000 xxxx xxxx xxxx 01x1 xxxx :Q */
/* SMUSD : cccc 0111 0000 xxxx 1111 xxxx 01x1 xxxx : */
/* SMMLA : cccc 0111 0101 xxxx xxxx xxxx 00x1 xxxx : */
/* SMMUL : cccc 0111 0101 xxxx 1111 xxxx 00x1 xxxx : */
/* USADA8 : cccc 0111 1000 xxxx xxxx xxxx 0001 xxxx : */
/* USAD8 : cccc 0111 1000 xxxx 1111 xxxx 0001 xxxx : */
if ((insn & 0x0ff00090) == 0x07000010 ||
(insn & 0x0ff000d0) == 0x07500010 ||
(insn & 0x0ff000f0) == 0x07800010) {
if ((insn & 0x0000f000) == 0x0000f000)
return prep_emulate_rd16rs8rm0_wflags(insn, asi);
else
return prep_emulate_rd16rn12rs8rm0_wflags(insn, asi);
}
/* SMMLS : cccc 0111 0101 xxxx xxxx xxxx 11x1 xxxx : */
if ((insn & 0x0ff000d0) == 0x075000d0)
return prep_emulate_rd16rn12rs8rm0_wflags(insn, asi);
/* SBFX : cccc 0111 101x xxxx xxxx xxxx x101 xxxx : */
/* UBFX : cccc 0111 111x xxxx xxxx xxxx x101 xxxx : */
if ((insn & 0x0fa00070) == 0x07a00050)
return prep_emulate_rd12rm0(insn, asi);
/* BFI : cccc 0111 110x xxxx xxxx xxxx x001 xxxx : */
/* BFC : cccc 0111 110x xxxx xxxx xxxx x001 1111 : */
if ((insn & 0x0fe00070) == 0x07c00010) {
if ((insn & 0x0000000f) == 0x0000000f)
return prep_emulate_rd12_modify(insn, asi);
else
return prep_emulate_rd12rn0_modify(insn, asi);
}
return INSN_REJECTED;
}
static enum kprobe_insn __kprobes
space_cccc_01xx(kprobe_opcode_t insn, struct arch_specific_insn *asi)
{
/* LDR : cccc 01xx x0x1 xxxx xxxx xxxx xxxx xxxx */
/* LDRB : cccc 01xx x1x1 xxxx xxxx xxxx xxxx xxxx */
/* LDRBT : cccc 01x0 x111 xxxx xxxx xxxx xxxx xxxx */
/* LDRT : cccc 01x0 x011 xxxx xxxx xxxx xxxx xxxx */
/* STR : cccc 01xx x0x0 xxxx xxxx xxxx xxxx xxxx */
/* STRB : cccc 01xx x1x0 xxxx xxxx xxxx xxxx xxxx */
/* STRBT : cccc 01x0 x110 xxxx xxxx xxxx xxxx xxxx */
/* STRT : cccc 01x0 x010 xxxx xxxx xxxx xxxx xxxx */
if ((insn & 0x00500000) == 0x00500000 && is_r15(insn, 12))
return INSN_REJECTED; /* LDRB into PC */
return prep_emulate_ldr_str(insn, asi);
}
static enum kprobe_insn __kprobes
space_cccc_100x(kprobe_opcode_t insn, struct arch_specific_insn *asi)
{
/* LDM(2) : cccc 100x x101 xxxx 0xxx xxxx xxxx xxxx */
/* LDM(3) : cccc 100x x1x1 xxxx 1xxx xxxx xxxx xxxx */
if ((insn & 0x0e708000) == 0x85000000 ||
(insn & 0x0e508000) == 0x85010000)
return INSN_REJECTED;
/* LDM(1) : cccc 100x x0x1 xxxx xxxx xxxx xxxx xxxx */
/* STM(1) : cccc 100x x0x0 xxxx xxxx xxxx xxxx xxxx */
asi->insn_handler = ((insn & 0x108000) == 0x008000) ? /* STM & R15 */
simulate_stm1_pc : simulate_ldm1stm1;
return INSN_GOOD_NO_SLOT;
}
static enum kprobe_insn __kprobes
space_cccc_101x(kprobe_opcode_t insn, struct arch_specific_insn *asi)
{
/* B : cccc 1010 xxxx xxxx xxxx xxxx xxxx xxxx */
/* BL : cccc 1011 xxxx xxxx xxxx xxxx xxxx xxxx */
asi->insn_handler = simulate_bbl;
return INSN_GOOD_NO_SLOT;
}
static enum kprobe_insn __kprobes
space_cccc_11xx(kprobe_opcode_t insn, struct arch_specific_insn *asi)
{
/* Coprocessor instructions... */
/* MCRR : cccc 1100 0100 xxxx xxxx xxxx xxxx xxxx : (Rd!=Rn) */
/* MRRC : cccc 1100 0101 xxxx xxxx xxxx xxxx xxxx : (Rd!=Rn) */
/* LDC : cccc 110x xxx1 xxxx xxxx xxxx xxxx xxxx */
/* STC : cccc 110x xxx0 xxxx xxxx xxxx xxxx xxxx */
/* CDP : cccc 1110 xxxx xxxx xxxx xxxx xxx0 xxxx */
/* MCR : cccc 1110 xxx0 xxxx xxxx xxxx xxx1 xxxx */
/* MRC : cccc 1110 xxx1 xxxx xxxx xxxx xxx1 xxxx */
/* SVC : cccc 1111 xxxx xxxx xxxx xxxx xxxx xxxx */
return INSN_REJECTED;
}
static unsigned long __kprobes __check_eq(unsigned long cpsr)
{
return cpsr & PSR_Z_BIT;
}
static unsigned long __kprobes __check_ne(unsigned long cpsr)
{
return (~cpsr) & PSR_Z_BIT;
}
static unsigned long __kprobes __check_cs(unsigned long cpsr)
{
return cpsr & PSR_C_BIT;
}
static unsigned long __kprobes __check_cc(unsigned long cpsr)
{
return (~cpsr) & PSR_C_BIT;
}
static unsigned long __kprobes __check_mi(unsigned long cpsr)
{
return cpsr & PSR_N_BIT;
}
static unsigned long __kprobes __check_pl(unsigned long cpsr)
{
return (~cpsr) & PSR_N_BIT;
}
static unsigned long __kprobes __check_vs(unsigned long cpsr)
{
return cpsr & PSR_V_BIT;
}
static unsigned long __kprobes __check_vc(unsigned long cpsr)
{
return (~cpsr) & PSR_V_BIT;
}
static unsigned long __kprobes __check_hi(unsigned long cpsr)
{
cpsr &= ~(cpsr >> 1); /* PSR_C_BIT &= ~PSR_Z_BIT */
return cpsr & PSR_C_BIT;
}
static unsigned long __kprobes __check_ls(unsigned long cpsr)
{
cpsr &= ~(cpsr >> 1); /* PSR_C_BIT &= ~PSR_Z_BIT */
return (~cpsr) & PSR_C_BIT;
}
static unsigned long __kprobes __check_ge(unsigned long cpsr)
{
cpsr ^= (cpsr << 3); /* PSR_N_BIT ^= PSR_V_BIT */
return (~cpsr) & PSR_N_BIT;
}
static unsigned long __kprobes __check_lt(unsigned long cpsr)
{
cpsr ^= (cpsr << 3); /* PSR_N_BIT ^= PSR_V_BIT */
return cpsr & PSR_N_BIT;
}
static unsigned long __kprobes __check_gt(unsigned long cpsr)
{
unsigned long temp = cpsr ^ (cpsr << 3); /* PSR_N_BIT ^= PSR_V_BIT */
temp |= (cpsr << 1); /* PSR_N_BIT |= PSR_Z_BIT */
return (~temp) & PSR_N_BIT;
}
static unsigned long __kprobes __check_le(unsigned long cpsr)
{
unsigned long temp = cpsr ^ (cpsr << 3); /* PSR_N_BIT ^= PSR_V_BIT */
temp |= (cpsr << 1); /* PSR_N_BIT |= PSR_Z_BIT */
return temp & PSR_N_BIT;
}
static unsigned long __kprobes __check_al(unsigned long cpsr)
{
return true;
}
static kprobe_check_cc * const condition_checks[16] = {
&__check_eq, &__check_ne, &__check_cs, &__check_cc,
&__check_mi, &__check_pl, &__check_vs, &__check_vc,
&__check_hi, &__check_ls, &__check_ge, &__check_lt,
&__check_gt, &__check_le, &__check_al, &__check_al
};
/* Return:
* INSN_REJECTED If instruction is one not allowed to kprobe,
* INSN_GOOD If instruction is supported and uses instruction slot,
* INSN_GOOD_NO_SLOT If instruction is supported but doesn't use its slot.
*
* For instructions we don't want to kprobe (INSN_REJECTED return result):
* These are generally ones that modify the processor state making
* them "hard" to simulate such as switches processor modes or
* make accesses in alternate modes. Any of these could be simulated
* if the work was put into it, but low return considering they
* should also be very rare.
*/
enum kprobe_insn __kprobes
arm_kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi)
{
asi->insn_check_cc = condition_checks[insn>>28];
asi->insn[1] = KPROBE_RETURN_INSTRUCTION;
if ((insn & 0xf0000000) == 0xf0000000)
return space_1111(insn, asi);
else if ((insn & 0x0e000000) == 0x00000000)
return space_cccc_000x(insn, asi);
else if ((insn & 0x0e000000) == 0x02000000)
return space_cccc_001x(insn, asi);
else if ((insn & 0x0f000010) == 0x06000010)
return space_cccc_0110__1(insn, asi);
else if ((insn & 0x0f000010) == 0x07000010)
return space_cccc_0111__1(insn, asi);
else if ((insn & 0x0c000000) == 0x04000000)
return space_cccc_01xx(insn, asi);
else if ((insn & 0x0e000000) == 0x08000000)
return space_cccc_100x(insn, asi);
else if ((insn & 0x0e000000) == 0x0a000000)
return space_cccc_101x(insn, asi);
return space_cccc_11xx(insn, asi);
}
void __init arm_kprobe_decode_init(void)
{
find_str_pc_offset();
}
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