From ba640a591574036ab22cd32b47897340b0605342 Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Wed, 5 Jan 2011 12:47:19 +0100 Subject: [PATCH] [S390] kprobes: instruction fixup Determine instruction fixup details in resume_execution, no need to do it beforehand. Remove fixup, ilen and reg from arch_specific_insn. Signed-off-by: Martin Schwidefsky --- arch/s390/include/asm/kprobes.h | 5 -- arch/s390/kernel/kprobes.c | 130 ++++++++++++++++++---------------------- 2 files changed, 57 insertions(+), 78 deletions(-) diff --git a/arch/s390/include/asm/kprobes.h b/arch/s390/include/asm/kprobes.h index e45b3d38d4f8..787c6a870329 100644 --- a/arch/s390/include/asm/kprobes.h +++ b/arch/s390/include/asm/kprobes.h @@ -59,9 +59,6 @@ typedef u16 kprobe_opcode_t; struct arch_specific_insn { /* copy of original instruction */ kprobe_opcode_t *insn; - int fixup; - int ilen; - int reg; }; struct prev_kprobe { @@ -83,8 +80,6 @@ struct kprobe_ctlblk { void arch_remove_kprobe(struct kprobe *p); void kretprobe_trampoline(void); -int is_prohibited_opcode(kprobe_opcode_t *instruction); -void get_instruction_type(struct arch_specific_insn *ainsn); int kprobe_fault_handler(struct pt_regs *regs, int trapnr); int kprobe_exceptions_notify(struct notifier_block *self, diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c index 1e75ec523577..fcbc25836879 100644 --- a/arch/s390/kernel/kprobes.c +++ b/arch/s390/kernel/kprobes.c @@ -37,29 +37,9 @@ DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}}; -int __kprobes arch_prepare_kprobe(struct kprobe *p) +static int __kprobes is_prohibited_opcode(kprobe_opcode_t *insn) { - /* Make sure the probe isn't going on a difficult instruction */ - if (is_prohibited_opcode((kprobe_opcode_t *) p->addr)) - return -EINVAL; - - if ((unsigned long)p->addr & 0x01) - return -EINVAL; - - /* Use the get_insn_slot() facility for correctness */ - if (!(p->ainsn.insn = get_insn_slot())) - return -ENOMEM; - - memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t)); - - get_instruction_type(&p->ainsn); - p->opcode = *p->addr; - return 0; -} - -int __kprobes is_prohibited_opcode(kprobe_opcode_t *instruction) -{ - switch (*(__u8 *) instruction) { + switch (insn[0] >> 8) { case 0x0c: /* bassm */ case 0x0b: /* bsm */ case 0x83: /* diag */ @@ -68,7 +48,7 @@ int __kprobes is_prohibited_opcode(kprobe_opcode_t *instruction) case 0xad: /* stosm */ return -EINVAL; } - switch (*(__u16 *) instruction) { + switch (insn[0]) { case 0x0101: /* pr */ case 0xb25a: /* bsa */ case 0xb240: /* bakr */ @@ -81,80 +61,79 @@ int __kprobes is_prohibited_opcode(kprobe_opcode_t *instruction) return 0; } -void __kprobes get_instruction_type(struct arch_specific_insn *ainsn) +static int __kprobes get_fixup_type(kprobe_opcode_t *insn) { /* default fixup method */ - ainsn->fixup = FIXUP_PSW_NORMAL; - - /* save r1 operand */ - ainsn->reg = (*ainsn->insn & 0xf0) >> 4; - - /* save the instruction length (pop 5-5) in bytes */ - switch (*(__u8 *) (ainsn->insn) >> 6) { - case 0: - ainsn->ilen = 2; - break; - case 1: - case 2: - ainsn->ilen = 4; - break; - case 3: - ainsn->ilen = 6; - break; - } + int fixup = FIXUP_PSW_NORMAL; - switch (*(__u8 *) ainsn->insn) { + switch (insn[0] >> 8) { case 0x05: /* balr */ case 0x0d: /* basr */ - ainsn->fixup = FIXUP_RETURN_REGISTER; + fixup = FIXUP_RETURN_REGISTER; /* if r2 = 0, no branch will be taken */ - if ((*ainsn->insn & 0x0f) == 0) - ainsn->fixup |= FIXUP_BRANCH_NOT_TAKEN; + if ((insn[0] & 0x0f) == 0) + fixup |= FIXUP_BRANCH_NOT_TAKEN; break; case 0x06: /* bctr */ case 0x07: /* bcr */ - ainsn->fixup = FIXUP_BRANCH_NOT_TAKEN; + fixup = FIXUP_BRANCH_NOT_TAKEN; break; case 0x45: /* bal */ case 0x4d: /* bas */ - ainsn->fixup = FIXUP_RETURN_REGISTER; + fixup = FIXUP_RETURN_REGISTER; break; case 0x47: /* bc */ case 0x46: /* bct */ case 0x86: /* bxh */ case 0x87: /* bxle */ - ainsn->fixup = FIXUP_BRANCH_NOT_TAKEN; + fixup = FIXUP_BRANCH_NOT_TAKEN; break; case 0x82: /* lpsw */ - ainsn->fixup = FIXUP_NOT_REQUIRED; + fixup = FIXUP_NOT_REQUIRED; break; case 0xb2: /* lpswe */ - if (*(((__u8 *) ainsn->insn) + 1) == 0xb2) { - ainsn->fixup = FIXUP_NOT_REQUIRED; - } + if ((insn[0] & 0xff) == 0xb2) + fixup = FIXUP_NOT_REQUIRED; break; case 0xa7: /* bras */ - if ((*ainsn->insn & 0x0f) == 0x05) { - ainsn->fixup |= FIXUP_RETURN_REGISTER; - } + if ((insn[0] & 0x0f) == 0x05) + fixup |= FIXUP_RETURN_REGISTER; break; case 0xc0: - if ((*ainsn->insn & 0x0f) == 0x00 /* larl */ - || (*ainsn->insn & 0x0f) == 0x05) /* brasl */ - ainsn->fixup |= FIXUP_RETURN_REGISTER; + if ((insn[0] & 0x0f) == 0x00 || /* larl */ + (insn[0] & 0x0f) == 0x05) /* brasl */ + fixup |= FIXUP_RETURN_REGISTER; break; case 0xeb: - if (*(((__u8 *) ainsn->insn) + 5 ) == 0x44 || /* bxhg */ - *(((__u8 *) ainsn->insn) + 5) == 0x45) {/* bxleg */ - ainsn->fixup = FIXUP_BRANCH_NOT_TAKEN; - } + if ((insn[2] & 0xff) == 0x44 || /* bxhg */ + (insn[2] & 0xff) == 0x45) /* bxleg */ + fixup = FIXUP_BRANCH_NOT_TAKEN; break; case 0xe3: /* bctg */ - if (*(((__u8 *) ainsn->insn) + 5) == 0x46) { - ainsn->fixup = FIXUP_BRANCH_NOT_TAKEN; - } + if ((insn[2] & 0xff) == 0x46) + fixup = FIXUP_BRANCH_NOT_TAKEN; break; } + return fixup; +} + +int __kprobes arch_prepare_kprobe(struct kprobe *p) +{ + if ((unsigned long) p->addr & 0x01) + return -EINVAL; + + /* Make sure the probe isn't going on a difficult instruction */ + if (is_prohibited_opcode((kprobe_opcode_t *) p->addr)) + return -EINVAL; + + /* Use the get_insn_slot() facility for correctness */ + if (!(p->ainsn.insn = get_insn_slot())) + return -ENOMEM; + + p->opcode = *p->addr; + memcpy(p->ainsn.insn, p->addr, ((p->opcode >> 14) + 3) & -2); + + return 0; } struct ins_replace_args { @@ -444,17 +423,22 @@ static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs) { struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); unsigned long ip = regs->psw.addr & PSW_ADDR_INSN; + int fixup = get_fixup_type(p->ainsn.insn); - if (p->ainsn.fixup & FIXUP_PSW_NORMAL) + if (fixup & FIXUP_PSW_NORMAL) ip += (unsigned long) p->addr - (unsigned long) p->ainsn.insn; - if (p->ainsn.fixup & FIXUP_BRANCH_NOT_TAKEN) - if (ip - (unsigned long) p->ainsn.insn == p->ainsn.ilen) - ip = (unsigned long) p->addr + p->ainsn.ilen; + if (fixup & FIXUP_BRANCH_NOT_TAKEN) { + int ilen = ((p->ainsn.insn[0] >> 14) + 3) & -2; + if (ip - (unsigned long) p->ainsn.insn == ilen) + ip = (unsigned long) p->addr + ilen; + } - if (p->ainsn.fixup & FIXUP_RETURN_REGISTER) - regs->gprs[p->ainsn.reg] += (unsigned long) p->addr - - (unsigned long) p->ainsn.insn; + if (fixup & FIXUP_RETURN_REGISTER) { + int reg = (p->ainsn.insn[0] & 0xf0) >> 4; + regs->gprs[reg] += (unsigned long) p->addr - + (unsigned long) p->ainsn.insn; + } disable_singlestep(kcb, regs, ip); } -- 2.11.0