From mboxrd@z Thu Jan 1 00:00:00 1970 From: ben.dooks@codethink.co.uk (Ben Dooks) Date: Wed, 31 Jul 2013 20:43:07 +0100 Subject: [PATCH 1/4] ARM: kprobes: fix instruction fetch order with In-Reply-To: <1375084901.3521.3.camel@linaro1.home> References: <1374786537-10726-1-git-send-email-ben.dooks@codethink.co.uk> <1374786537-10726-2-git-send-email-ben.dooks@codethink.co.uk> <1375084901.3521.3.camel@linaro1.home> Message-ID: <51F968CB.8060605@codethink.co.uk> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 29/07/13 09:01, Jon Medhurst (Tixy) wrote: > On Thu, 2013-07-25 at 22:08 +0100, Ben Dooks wrote: >> If we are running BE8, the data and instruction endian-ness do not >> match, so use to correctly translate memory accesses >> into ARM instructions. >> >> Signed-off-by: Ben Dooksy >> --- >> arch/arm/kernel/kprobes-common.c | 14 ++++++++------ >> arch/arm/kernel/kprobes.c | 9 +++++---- >> 2 files changed, 13 insertions(+), 10 deletions(-) >> >> diff --git a/arch/arm/kernel/kprobes-common.c b/arch/arm/kernel/kprobes-common.c >> index 18a7628..c0b202e 100644 >> --- a/arch/arm/kernel/kprobes-common.c >> +++ b/arch/arm/kernel/kprobes-common.c >> @@ -14,6 +14,7 @@ >> #include >> #include >> #include >> +#include >> >> #include "kprobes.h" >> >> @@ -305,7 +306,8 @@ kprobe_decode_ldmstm(kprobe_opcode_t insn, struct arch_specific_insn *asi) >> >> if (handler) { >> /* We can emulate the instruction in (possibly) modified form */ >> - asi->insn[0] = (insn& 0xfff00000) | (rn<< 16) | reglist; >> + asi->insn[0] = __opcode_to_mem_arm((insn& 0xfff00000) | >> + (rn<< 16) | reglist); >> asi->insn_handler = handler; >> return INSN_GOOD; >> } >> @@ -338,9 +340,9 @@ prepare_emulated_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi, >> thumb_insn[2] = 0x4770; /* Thumb bx lr */ > > The line above and the one before it not in this diff also need fixing > by changing to __opcode_to_mem_thumb16(0x4770). IIRC, these are then fixed by the set_emulated instruction, which is also why the insn return is not swapped. >> return insn; >> } >> - asi->insn[1] = 0xe12fff1e; /* ARM bx lr */ >> + asi->insn[1] = __opcode_to_mem_arm(0xe12fff1e); /* ARM bx lr */ >> #else >> - asi->insn[1] = 0xe1a0f00e; /* mov pc, lr */ >> + asi->insn[1] = __opcode_to_mem_arm(0xe1a0f00e); /* mov pc, lr */ >> #endif >> /* Make an ARM instruction unconditional */ >> if (insn< 0xe0000000) >> @@ -360,12 +362,12 @@ set_emulated_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi, >> if (thumb) { >> u16 *ip = (u16 *)asi->insn; >> if (is_wide_instruction(insn)) >> - *ip++ = insn>> 16; >> - *ip++ = insn; >> + *ip++ = ___asm_opcode_to_mem_thumb16(insn>> 16); >> + *ip++ = ___asm_opcode_to_mem_thumb16(insn); > > > Should these two ___asm_opcode_thumb32_compose() not be > __opcode_thumb32_compose() ? I decided to leave this as is. >> return; >> } >> #endif >> - asi->insn[0] = insn; >> + asi->insn[0] = __opcode_to_mem_arm(insn); >> } >> >> /* >> diff --git a/arch/arm/kernel/kprobes.c b/arch/arm/kernel/kprobes.c >> index 170e9f3..3775af1 100644 >> --- a/arch/arm/kernel/kprobes.c >> +++ b/arch/arm/kernel/kprobes.c >> @@ -26,6 +26,7 @@ >> #include >> #include >> #include >> +#include >> #include >> >> #include "kprobes.h" >> @@ -62,10 +63,10 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p) >> #ifdef CONFIG_THUMB2_KERNEL >> thumb = true; >> addr&= ~1; /* Bit 0 would normally be set to indicate Thumb code */ >> - insn = ((u16 *)addr)[0]; >> + insn = __mem_to_opcode_thumb16(((u16 *)addr)[0]); >> if (is_wide_instruction(insn)) { >> - insn<<= 16; >> - insn |= ((u16 *)addr)[1]; >> + u16 inst2 = __mem_to_opcode_thumb16(((u16 *)addr)[1]); >> + insn = ___asm_opcode_thumb32_compose(insn, inst2); > > Again, __opcode_thumb32_compose instead of > ___asm_opcode_thumb32_compose > >> decode_insn = thumb32_kprobe_decode_insn; >> } else >> decode_insn = thumb16_kprobe_decode_insn; >> @@ -73,7 +74,7 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p) >> thumb = false; >> if (addr& 0x3) >> return -EINVAL; >> - insn = *p->addr; >> + insn = __mem_to_opcode_arm(*p->addr); >> decode_insn = arm_kprobe_decode_insn; >> #endif >> > -- Ben Dooks http://www.codethink.co.uk/ Senior Engineer Codethink - Providing Genius