From 2437170710c4a3dee137a65623960aa7ac82a32e Mon Sep 17 00:00:00 2001 From: Jon Medhurst Date: Tue, 19 Apr 2011 17:56:58 +0100 Subject: [PATCH] ARM: kprobes: Add Thumb instruction decoding stubs Extend arch_prepare_kprobe to support probing of Thumb code. For the actual decoding of Thumb instructions, stub functions are added which currently just reject the probe. Signed-off-by: Jon Medhurst Acked-by: Nicolas Pitre --- arch/arm/kernel/Makefile | 4 ++++ arch/arm/kernel/kprobes-thumb.c | 26 ++++++++++++++++++++++++++ arch/arm/kernel/kprobes.c | 20 ++++++++++++++++++-- arch/arm/kernel/kprobes.h | 13 +++++++++++++ 4 files changed, 61 insertions(+), 2 deletions(-) create mode 100644 arch/arm/kernel/kprobes-thumb.c diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile index a22b8f1..f7887dc 100644 --- a/arch/arm/kernel/Makefile +++ b/arch/arm/kernel/Makefile @@ -38,7 +38,11 @@ obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o obj-$(CONFIG_KPROBES) += kprobes.o kprobes-common.o +ifdef CONFIG_THUMB2_KERNEL +obj-$(CONFIG_KPROBES) += kprobes-thumb.o +else obj-$(CONFIG_KPROBES) += kprobes-arm.o +endif obj-$(CONFIG_ATAGS_PROC) += atags.o obj-$(CONFIG_OABI_COMPAT) += sys_oabi-compat.o obj-$(CONFIG_ARM_THUMBEE) += thumbee.o diff --git a/arch/arm/kernel/kprobes-thumb.c b/arch/arm/kernel/kprobes-thumb.c new file mode 100644 index 0000000..ac6b2d1 --- /dev/null +++ b/arch/arm/kernel/kprobes-thumb.c @@ -0,0 +1,26 @@ +/* + * arch/arm/kernel/kprobes-thumb.c + * + * Copyright (C) 2011 Jon Medhurst . + * + * 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 +#include + +#include "kprobes.h" + +enum kprobe_insn __kprobes +thumb16_kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi) +{ + return INSN_REJECTED; +} + +enum kprobe_insn __kprobes +thumb32_kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi) +{ + return INSN_REJECTED; +} diff --git a/arch/arm/kernel/kprobes.c b/arch/arm/kernel/kprobes.c index 0e47d3d..0df2d6d 100644 --- a/arch/arm/kernel/kprobes.c +++ b/arch/arm/kernel/kprobes.c @@ -51,16 +51,32 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p) kprobe_opcode_t insn; kprobe_opcode_t tmp_insn[MAX_INSN_SIZE]; unsigned long addr = (unsigned long)p->addr; + kprobe_decode_insn_t *decode_insn; int is; - if (addr & 0x3 || in_exception_text(addr)) + if (in_exception_text(addr)) return -EINVAL; +#ifdef CONFIG_THUMB2_KERNEL + addr &= ~1; /* Bit 0 would normally be set to indicate Thumb code */ + insn = ((u16 *)addr)[0]; + if (is_wide_instruction(insn)) { + insn <<= 16; + insn |= ((u16 *)addr)[1]; + decode_insn = thumb32_kprobe_decode_insn; + } else + decode_insn = thumb16_kprobe_decode_insn; +#else /* !CONFIG_THUMB2_KERNEL */ + if (addr & 0x3) + return -EINVAL; insn = *p->addr; + decode_insn = arm_kprobe_decode_insn; +#endif + p->opcode = insn; p->ainsn.insn = tmp_insn; - switch (arm_kprobe_decode_insn(insn, &p->ainsn)) { + switch ((*decode_insn)(insn, &p->ainsn)) { case INSN_REJECTED: /* not supported */ return -EINVAL; diff --git a/arch/arm/kernel/kprobes.h b/arch/arm/kernel/kprobes.h index 406bb2d..86abfab 100644 --- a/arch/arm/kernel/kprobes.h +++ b/arch/arm/kernel/kprobes.h @@ -29,8 +29,21 @@ enum kprobe_insn { INSN_GOOD_NO_SLOT }; +typedef enum kprobe_insn (kprobe_decode_insn_t)(kprobe_opcode_t, + struct arch_specific_insn *); + +#ifdef CONFIG_THUMB2_KERNEL + +enum kprobe_insn thumb16_kprobe_decode_insn(kprobe_opcode_t, + struct arch_specific_insn *); +enum kprobe_insn thumb32_kprobe_decode_insn(kprobe_opcode_t, + struct arch_specific_insn *); + +#else /* !CONFIG_THUMB2_KERNEL */ + enum kprobe_insn arm_kprobe_decode_insn(kprobe_opcode_t, struct arch_specific_insn *); +#endif void __init arm_kprobe_decode_init(void); -- 2.7.4