kprobes-decode.c
/*
* 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, ®s->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, ®s->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, ®s->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, ®s->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,
®s->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, ®s->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, ®s->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, ®s->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, ®s->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();
}
