iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

ARM: kprobes: check register usage for probed instruction.

Browse Source 
This patch utilizes the previously introduced checker to check
register usage for probed ARM instruction and saves it in a mask.
A further patch will use such information to avoid simulation or
emulation.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Reviewed-by: Jon Medhurst <tixy@linaro.org>
Signed-off-by: Jon Medhurst <tixy@linaro.org>
This commit is contained in:
Wang Nan 2015-01-05 19:29:44 +08:00 committed by Jon Medhurst
parent 4cd872d973
commit 28a1899db3
5 changed files with 103 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/arm/include/asm/probes.h
View File

@ -41,6 +41,7 @@ struct arch_probes_insn {
probes_insn_singlestep_t *insn_singlestep;
probes_insn_fn_t *insn_fn;
int stack_space;
unsigned long register_usage_flags;
};
#endif /* __ASSEMBLY__ */

7
arch/arm/probes/decode.c
View File

@ -435,6 +435,13 @@ probes_decode_insn(probes_opcode_t insn, struct arch_probes_insn *asi,
*/
asi->stack_space = 0;
/*
* Similarly to stack_space, register_usage_flags is filled by
* checkers. Its default value is set to ~0, which is 'all
* registers are used', to prevent any potential optimization.
*/
asi->register_usage_flags = ~0UL;
if (emulate)
insn = prepare_emulated_insn(insn, asi, thumb);

2
arch/arm/probes/kprobes/actions-arm.c
View File

@ -341,4 +341,4 @@ const union decode_action kprobes_arm_actions[NUM_PROBES_ARM_ACTIONS] = {
[PROBES_LDMSTM] = {.decoder = kprobe_decode_ldmstm}
};
const struct decode_checker *kprobes_arm_checkers[] = {arm_stack_checker, NULL};
const struct decode_checker *kprobes_arm_checkers[] = {arm_stack_checker, arm_regs_checker, NULL};

93
arch/arm/probes/kprobes/checkers-arm.c
View File

@ -97,3 +97,96 @@ const struct decode_checker arm_stack_checker[NUM_PROBES_ARM_ACTIONS] = {
[PROBES_STORE] = {.checker = arm_check_stack},
[PROBES_LDMSTM] = {.checker = arm_check_stack},
};
static enum probes_insn __kprobes arm_check_regs_nouse(probes_opcode_t insn,
struct arch_probes_insn *asi,
const struct decode_header *h)
{
asi->register_usage_flags = 0;
return INSN_GOOD;
}
static enum probes_insn arm_check_regs_normal(probes_opcode_t insn,
struct arch_probes_insn *asi,
const struct decode_header *h)
{
u32 regs = h->type_regs.bits >> DECODE_TYPE_BITS;
int i;
asi->register_usage_flags = 0;
for (i = 0; i < 5; regs >>= 4, insn >>= 4, i++)
if (regs & 0xf)
asi->register_usage_flags |= 1 << (insn & 0xf);
return INSN_GOOD;
}
static enum probes_insn arm_check_regs_ldmstm(probes_opcode_t insn,
struct arch_probes_insn *asi,
const struct decode_header *h)
{
unsigned int reglist = insn & 0xffff;
unsigned int rn = (insn >> 16) & 0xf;
asi->register_usage_flags = reglist | (1 << rn);
return INSN_GOOD;
}
static enum probes_insn arm_check_regs_mov_ip_sp(probes_opcode_t insn,
struct arch_probes_insn *asi,
const struct decode_header *h)
{
/* Instruction is 'mov ip, sp' i.e. 'mov r12, r13' */
asi->register_usage_flags = (1 << 12) | (1<< 13);
return INSN_GOOD;
}
/*
* | Rn |Rt/d| | Rm |
* LDRD (register) cccc 000x x0x0 xxxx xxxx xxxx 1101 xxxx
* STRD (register) cccc 000x x0x0 xxxx xxxx xxxx 1111 xxxx
* | Rn |Rt/d| |imm4L|
* LDRD (immediate) cccc 000x x1x0 xxxx xxxx xxxx 1101 xxxx
* STRD (immediate) cccc 000x x1x0 xxxx xxxx xxxx 1111 xxxx
*
* Such instructions access Rt/d and its next register, so different
* from others, a specific checker is required to handle this extra
* implicit register usage.
*/
static enum probes_insn arm_check_regs_ldrdstrd(probes_opcode_t insn,
struct arch_probes_insn *asi,
const struct decode_header *h)
{
int rdt = (insn >> 12) & 0xf;
arm_check_regs_normal(insn, asi, h);
asi->register_usage_flags |= 1 << (rdt + 1);
return INSN_GOOD;
}
const struct decode_checker arm_regs_checker[NUM_PROBES_ARM_ACTIONS] = {
[PROBES_MRS] = {.checker = arm_check_regs_normal},
[PROBES_SATURATING_ARITHMETIC] = {.checker = arm_check_regs_normal},
[PROBES_MUL1] = {.checker = arm_check_regs_normal},
[PROBES_MUL2] = {.checker = arm_check_regs_normal},
[PROBES_MUL_ADD_LONG] = {.checker = arm_check_regs_normal},
[PROBES_MUL_ADD] = {.checker = arm_check_regs_normal},
[PROBES_LOAD] = {.checker = arm_check_regs_normal},
[PROBES_LOAD_EXTRA] = {.checker = arm_check_regs_normal},
[PROBES_STORE] = {.checker = arm_check_regs_normal},
[PROBES_STORE_EXTRA] = {.checker = arm_check_regs_normal},
[PROBES_DATA_PROCESSING_REG] = {.checker = arm_check_regs_normal},
[PROBES_DATA_PROCESSING_IMM] = {.checker = arm_check_regs_normal},
[PROBES_SEV] = {.checker = arm_check_regs_nouse},
[PROBES_WFE] = {.checker = arm_check_regs_nouse},
[PROBES_SATURATE] = {.checker = arm_check_regs_normal},
[PROBES_REV] = {.checker = arm_check_regs_normal},
[PROBES_MMI] = {.checker = arm_check_regs_normal},
[PROBES_PACK] = {.checker = arm_check_regs_normal},
[PROBES_EXTEND] = {.checker = arm_check_regs_normal},
[PROBES_EXTEND_ADD] = {.checker = arm_check_regs_normal},
[PROBES_BITFIELD] = {.checker = arm_check_regs_normal},
[PROBES_LDMSTM] = {.checker = arm_check_regs_ldmstm},
[PROBES_MOV_IP_SP] = {.checker = arm_check_regs_mov_ip_sp},
[PROBES_LDRSTRD] = {.checker = arm_check_regs_ldrdstrd},
};

1
arch/arm/probes/kprobes/checkers.h
View File

@ -47,6 +47,7 @@ extern const union decode_action stack_check_actions[];
#ifndef CONFIG_THUMB2_KERNEL
extern const struct decode_checker arm_stack_checker[];
extern const struct decode_checker arm_regs_checker[];
#else
#endif
extern const struct decode_checker t32_stack_checker[];