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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2011-01-05 12:47:19 +0100
committerMartin Schwidefsky <sky@mschwide.boeblingen.de.ibm.com>2011-01-05 12:47:23 +0100
commitba640a591574036ab22cd32b47897340b0605342 (patch)
tree271783643d438caa0c41a5dbc68e712a7a4c5484 /arch/s390/kernel
parent5a8b589f8a35b2c69d1819e3365825e4385a844c (diff)
downloadlinux-linaro-android-ba640a591574036ab22cd32b47897340b0605342.tar.gz
[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 <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/kernel')
-rw-r--r--arch/s390/kernel/kprobes.c130
1 files changed, 57 insertions, 73 deletions
diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c
index 1e75ec52357..fcbc2583687 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);
}