diff options
| author | Jon Medhurst <tixy@yxit.co.uk> | 2011-07-02 15:36:32 +0100 |
|---|---|---|
| committer | Tixy <tixy@medhuaa1.miniserver.com> | 2011-07-13 17:32:43 +0000 |
| commit | 3f92dfed6a9a5f490128c8e7cc6a64dfe412994f (patch) | |
| tree | 1d503b19d01075dfd1db1023b8d0e787f9d58bb6 | |
| parent | 0d1a095aa1e6e2a233bfb1729e15233e77f69d54 (diff) | |
ARM: kprobes: Decode 16-bit Thumb hint instructions
For hints which may have observable effects, like SEV (send event), we
use kprobe_emulate_none which emulates the hint by executing the
original instruction.
For NOP we simulate the instruction using kprobe_simulate_nop, which
does nothing. As probes execute with interrupts disabled this is also
used for hints which may block for an indefinite time, like WFE (wait
for event).
Signed-off-by: Jon Medhurst <tixy@yxit.co.uk>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
| -rw-r--r-- | arch/arm/kernel/kprobes-common.c | 9 | ||||
| -rw-r--r-- | arch/arm/kernel/kprobes-thumb.c | 35 | ||||
| -rw-r--r-- | arch/arm/kernel/kprobes.h | 3 |
3 files changed, 46 insertions, 1 deletions
diff --git a/arch/arm/kernel/kprobes-common.c b/arch/arm/kernel/kprobes-common.c index 1cb6a82a5e24..3a3e765d2090 100644 --- a/arch/arm/kernel/kprobes-common.c +++ b/arch/arm/kernel/kprobes-common.c @@ -142,6 +142,15 @@ kprobe_check_cc * const kprobe_condition_checks[16] = { }; +void __kprobes kprobe_simulate_nop(struct kprobe *p, struct pt_regs *regs) +{ +} + +void __kprobes kprobe_emulate_none(struct kprobe *p, struct pt_regs *regs) +{ + p->ainsn.insn_fn(); +} + /* * Prepare an instruction slot to receive an instruction for emulating. * This is done by placing a subroutine return after the location where the diff --git a/arch/arm/kernel/kprobes-thumb.c b/arch/arm/kernel/kprobes-thumb.c index 973c3eb1243a..7dcf6df4a85c 100644 --- a/arch/arm/kernel/kprobes-thumb.c +++ b/arch/arm/kernel/kprobes-thumb.c @@ -26,6 +26,39 @@ */ #define current_cond(cpsr) ((cpsr >> 12) & 0xf) +static const union decode_item t16_table_1011[] = { + /* Miscellaneous 16-bit instructions */ + + /* + * If-Then, and hints + * 1011 1111 xxxx xxxx + */ + + /* YIELD 1011 1111 0001 0000 */ + DECODE_OR (0xffff, 0xbf10), + /* SEV 1011 1111 0100 0000 */ + DECODE_EMULATE (0xffff, 0xbf40, kprobe_emulate_none), + /* NOP 1011 1111 0000 0000 */ + /* WFE 1011 1111 0010 0000 */ + /* WFI 1011 1111 0011 0000 */ + DECODE_SIMULATE (0xffcf, 0xbf00, kprobe_simulate_nop), + /* Unassigned hints 1011 1111 xxxx 0000 */ + DECODE_REJECT (0xff0f, 0xbf00), + + DECODE_END +}; + +const union decode_item kprobe_decode_thumb16_table[] = { + + /* + * Miscellaneous 16-bit instructions + * 1011 xxxx xxxx xxxx + */ + DECODE_TABLE (0xf000, 0xb000, t16_table_1011), + + DECODE_END +}; + static unsigned long __kprobes thumb_check_cc(unsigned long cpsr) { if (unlikely(in_it_block(cpsr))) @@ -52,7 +85,7 @@ thumb16_kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi) { asi->insn_singlestep = thumb16_singlestep; asi->insn_check_cc = thumb_check_cc; - return INSN_REJECTED; + return kprobe_decode_insn(insn, asi, kprobe_decode_thumb16_table, true); } enum kprobe_insn __kprobes diff --git a/arch/arm/kernel/kprobes.h b/arch/arm/kernel/kprobes.h index c00681ce5cce..36e07684fe08 100644 --- a/arch/arm/kernel/kprobes.h +++ b/arch/arm/kernel/kprobes.h @@ -95,6 +95,9 @@ static inline unsigned long it_advance(unsigned long cpsr) return cpsr; } +void __kprobes kprobe_simulate_nop(struct kprobe *p, struct pt_regs *regs); +void __kprobes kprobe_emulate_none(struct kprobe *p, struct pt_regs *regs); + /* * Test if load/store instructions writeback the address register. * if P (bit 24) == 0 or W (bit 21) == 1 |