234 lines
6.2 KiB
C
234 lines
6.2 KiB
C
/*
|
|
* Copyright (C) 2012 Rabin Vincent <rabin at rab.in>
|
|
*
|
|
* 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.
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/types.h>
|
|
#include <linux/stddef.h>
|
|
#include <linux/wait.h>
|
|
#include <linux/uprobes.h>
|
|
#include <linux/module.h>
|
|
|
|
#include "probes.h"
|
|
#include "probes-arm.h"
|
|
#include "uprobes.h"
|
|
|
|
static int uprobes_substitute_pc(unsigned long *pinsn, u32 oregs)
|
|
{
|
|
probes_opcode_t insn = __mem_to_opcode_arm(*pinsn);
|
|
probes_opcode_t temp;
|
|
probes_opcode_t mask;
|
|
int freereg;
|
|
u32 free = 0xffff;
|
|
u32 regs;
|
|
|
|
for (regs = oregs; regs; regs >>= 4, insn >>= 4) {
|
|
if ((regs & 0xf) == REG_TYPE_NONE)
|
|
continue;
|
|
|
|
free &= ~(1 << (insn & 0xf));
|
|
}
|
|
|
|
/* No PC, no problem */
|
|
if (free & (1 << 15))
|
|
return 15;
|
|
|
|
if (!free)
|
|
return -1;
|
|
|
|
/*
|
|
* fls instead of ffs ensures that for "ldrd r0, r1, [pc]" we would
|
|
* pick LR instead of R1.
|
|
*/
|
|
freereg = free = fls(free) - 1;
|
|
|
|
temp = __mem_to_opcode_arm(*pinsn);
|
|
insn = temp;
|
|
regs = oregs;
|
|
mask = 0xf;
|
|
|
|
for (; regs; regs >>= 4, mask <<= 4, free <<= 4, temp >>= 4) {
|
|
if ((regs & 0xf) == REG_TYPE_NONE)
|
|
continue;
|
|
|
|
if ((temp & 0xf) != 15)
|
|
continue;
|
|
|
|
insn &= ~mask;
|
|
insn |= free & mask;
|
|
}
|
|
|
|
*pinsn = __opcode_to_mem_arm(insn);
|
|
return freereg;
|
|
}
|
|
|
|
static void uprobe_set_pc(struct arch_uprobe *auprobe,
|
|
struct arch_uprobe_task *autask,
|
|
struct pt_regs *regs)
|
|
{
|
|
u32 pcreg = auprobe->pcreg;
|
|
|
|
autask->backup = regs->uregs[pcreg];
|
|
regs->uregs[pcreg] = regs->ARM_pc + 8;
|
|
}
|
|
|
|
static void uprobe_unset_pc(struct arch_uprobe *auprobe,
|
|
struct arch_uprobe_task *autask,
|
|
struct pt_regs *regs)
|
|
{
|
|
/* PC will be taken care of by common code */
|
|
regs->uregs[auprobe->pcreg] = autask->backup;
|
|
}
|
|
|
|
static void uprobe_aluwrite_pc(struct arch_uprobe *auprobe,
|
|
struct arch_uprobe_task *autask,
|
|
struct pt_regs *regs)
|
|
{
|
|
u32 pcreg = auprobe->pcreg;
|
|
|
|
alu_write_pc(regs->uregs[pcreg], regs);
|
|
regs->uregs[pcreg] = autask->backup;
|
|
}
|
|
|
|
static void uprobe_write_pc(struct arch_uprobe *auprobe,
|
|
struct arch_uprobe_task *autask,
|
|
struct pt_regs *regs)
|
|
{
|
|
u32 pcreg = auprobe->pcreg;
|
|
|
|
load_write_pc(regs->uregs[pcreg], regs);
|
|
regs->uregs[pcreg] = autask->backup;
|
|
}
|
|
|
|
enum probes_insn
|
|
decode_pc_ro(probes_opcode_t insn, struct arch_probes_insn *asi,
|
|
const struct decode_header *d)
|
|
{
|
|
struct arch_uprobe *auprobe = container_of(asi, struct arch_uprobe,
|
|
asi);
|
|
struct decode_emulate *decode = (struct decode_emulate *) d;
|
|
u32 regs = decode->header.type_regs.bits >> DECODE_TYPE_BITS;
|
|
int reg;
|
|
|
|
reg = uprobes_substitute_pc(&auprobe->ixol[0], regs);
|
|
if (reg == 15)
|
|
return INSN_GOOD;
|
|
|
|
if (reg == -1)
|
|
return INSN_REJECTED;
|
|
|
|
auprobe->pcreg = reg;
|
|
auprobe->prehandler = uprobe_set_pc;
|
|
auprobe->posthandler = uprobe_unset_pc;
|
|
|
|
return INSN_GOOD;
|
|
}
|
|
|
|
enum probes_insn
|
|
decode_wb_pc(probes_opcode_t insn, struct arch_probes_insn *asi,
|
|
const struct decode_header *d, bool alu)
|
|
{
|
|
struct arch_uprobe *auprobe = container_of(asi, struct arch_uprobe,
|
|
asi);
|
|
enum probes_insn ret = decode_pc_ro(insn, asi, d);
|
|
|
|
if (((insn >> 12) & 0xf) == 15)
|
|
auprobe->posthandler = alu ? uprobe_aluwrite_pc
|
|
: uprobe_write_pc;
|
|
|
|
return ret;
|
|
}
|
|
|
|
enum probes_insn
|
|
decode_rd12rn16rm0rs8_rwflags(probes_opcode_t insn,
|
|
struct arch_probes_insn *asi,
|
|
const struct decode_header *d)
|
|
{
|
|
return decode_wb_pc(insn, asi, d, true);
|
|
}
|
|
|
|
enum probes_insn
|
|
decode_ldr(probes_opcode_t insn, struct arch_probes_insn *asi,
|
|
const struct decode_header *d)
|
|
{
|
|
return decode_wb_pc(insn, asi, d, false);
|
|
}
|
|
|
|
enum probes_insn
|
|
uprobe_decode_ldmstm(probes_opcode_t insn,
|
|
struct arch_probes_insn *asi,
|
|
const struct decode_header *d)
|
|
{
|
|
struct arch_uprobe *auprobe = container_of(asi, struct arch_uprobe,
|
|
asi);
|
|
unsigned reglist = insn & 0xffff;
|
|
int rn = (insn >> 16) & 0xf;
|
|
int lbit = insn & (1 << 20);
|
|
unsigned used = reglist | (1 << rn);
|
|
|
|
if (rn == 15)
|
|
return INSN_REJECTED;
|
|
|
|
if (!(used & (1 << 15)))
|
|
return INSN_GOOD;
|
|
|
|
if (used & (1 << 14))
|
|
return INSN_REJECTED;
|
|
|
|
/* Use LR instead of PC */
|
|
insn ^= 0xc000;
|
|
|
|
auprobe->pcreg = 14;
|
|
auprobe->ixol[0] = __opcode_to_mem_arm(insn);
|
|
|
|
auprobe->prehandler = uprobe_set_pc;
|
|
if (lbit)
|
|
auprobe->posthandler = uprobe_write_pc;
|
|
else
|
|
auprobe->posthandler = uprobe_unset_pc;
|
|
|
|
return INSN_GOOD;
|
|
}
|
|
|
|
const union decode_action uprobes_probes_actions[] = {
|
|
[PROBES_EMULATE_NONE] = {.handler = probes_simulate_nop},
|
|
[PROBES_SIMULATE_NOP] = {.handler = probes_simulate_nop},
|
|
[PROBES_PRELOAD_IMM] = {.handler = probes_simulate_nop},
|
|
[PROBES_PRELOAD_REG] = {.handler = probes_simulate_nop},
|
|
[PROBES_BRANCH_IMM] = {.handler = simulate_blx1},
|
|
[PROBES_MRS] = {.handler = simulate_mrs},
|
|
[PROBES_BRANCH_REG] = {.handler = simulate_blx2bx},
|
|
[PROBES_CLZ] = {.handler = probes_simulate_nop},
|
|
[PROBES_SATURATING_ARITHMETIC] = {.handler = probes_simulate_nop},
|
|
[PROBES_MUL1] = {.handler = probes_simulate_nop},
|
|
[PROBES_MUL2] = {.handler = probes_simulate_nop},
|
|
[PROBES_SWP] = {.handler = probes_simulate_nop},
|
|
[PROBES_LDRSTRD] = {.decoder = decode_pc_ro},
|
|
[PROBES_LOAD_EXTRA] = {.decoder = decode_pc_ro},
|
|
[PROBES_LOAD] = {.decoder = decode_ldr},
|
|
[PROBES_STORE_EXTRA] = {.decoder = decode_pc_ro},
|
|
[PROBES_STORE] = {.decoder = decode_pc_ro},
|
|
[PROBES_MOV_IP_SP] = {.handler = simulate_mov_ipsp},
|
|
[PROBES_DATA_PROCESSING_REG] = {
|
|
.decoder = decode_rd12rn16rm0rs8_rwflags},
|
|
[PROBES_DATA_PROCESSING_IMM] = {
|
|
.decoder = decode_rd12rn16rm0rs8_rwflags},
|
|
[PROBES_MOV_HALFWORD] = {.handler = probes_simulate_nop},
|
|
[PROBES_SEV] = {.handler = probes_simulate_nop},
|
|
[PROBES_WFE] = {.handler = probes_simulate_nop},
|
|
[PROBES_SATURATE] = {.handler = probes_simulate_nop},
|
|
[PROBES_REV] = {.handler = probes_simulate_nop},
|
|
[PROBES_MMI] = {.handler = probes_simulate_nop},
|
|
[PROBES_PACK] = {.handler = probes_simulate_nop},
|
|
[PROBES_EXTEND] = {.handler = probes_simulate_nop},
|
|
[PROBES_EXTEND_ADD] = {.handler = probes_simulate_nop},
|
|
[PROBES_MUL_ADD_LONG] = {.handler = probes_simulate_nop},
|
|
[PROBES_MUL_ADD] = {.handler = probes_simulate_nop},
|
|
[PROBES_BITFIELD] = {.handler = probes_simulate_nop},
|
|
[PROBES_BRANCH] = {.handler = simulate_bbl},
|
|
[PROBES_LDMSTM] = {.decoder = uprobe_decode_ldmstm}
|
|
};
|